WorldWideScience

Sample records for type-ii active galactic

  1. Contributions of type II and Ib/c supernovae to Galactic chemical evolution

    International Nuclear Information System (INIS)

    Sahijpal Sandeep

    2014-01-01

    Type II and Ib/c supernovae (SNe II and Ib/c) have made major stellar nucleosynthetic contributions to the inventories of stable nuclides during chemical evolution of the Galaxy. A case study is performed here with the help of recently developed numerical simulations of Galactic chemical evolution in the solar neighborhood to understand the contributions of SNe II and Ib/c by comparing the stellar nucleosynthetic yields obtained by two leading groups in this field. These stellar nucleosynthetic yields differ in terms of their treatment of stellar evolution and nucleosynthesis. The formulation describing Galactic chemical evolution is developed with the recently revised solar metallicity of ∼0.014. Furthermore, the recent nucleosynthetic yields of stellar models based on the revised solar metallicity are also used. The analysis suggests that it could be difficult to explain, in a self-consistent manner, the various features associated with the elemental evolutionary trends over Galactic timescales by any single adopted stellar nucleosynthetic model that incorporates SNe II and Ib/c

  2. Active galactic nuclei

    CERN Document Server

    Blandford, RD; Woltjer, L

    1990-01-01

    Starting with this volume, the Lecture Notes of the renowned Advanced Courses of the Swiss Society for Astrophysics and Astronomy will be published annually. In each course, three extensive lectures given by leading experts in their respective fields cover different and essential aspects of the subject. The 20th course, held at Les Diablerets in April 1990, dealt with current research on active galactic nuclei; it represents the most up-to-date views on the subject, presented with particular regard for clarity. The previous courses considered a wide variety of subjects, beginning with ""Theory

  3. Elusive active galactic nuclei

    Science.gov (United States)

    Maiolino, R.; Comastri, A.; Gilli, R.; Nagar, N. M.; Bianchi, S.; Böker, T.; Colbert, E.; Krabbe, A.; Marconi, A.; Matt, G.; Salvati, M.

    2003-10-01

    A fraction of active galactic nuclei do not show the classical Seyfert-type signatures in their optical spectra, i.e. they are optically `elusive'. X-ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X-ray data in order to obtain a first estimate of the fraction of elusive active galactic nuclei (AGN) in local galaxies and to constrain their nature. Our results suggest that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei. Most elusive AGN are heavily absorbed in the X-rays, with gas column densities exceeding 1024 cm-2, suggesting that their peculiar nature is associated with obscuration. It is likely that in elusive AGN the nuclear UV source is completely embedded and the ionizing photons cannot escape, which prevents the formation of a classical narrow-line region. Elusive AGN may contribute significantly to the 30-keV bump of the X-ray background.

  4. 77 FR 60124 - Draft Guidance for Industry on Initial Completeness Assessments for Type II Active Pharmaceutical...

    Science.gov (United States)

    2012-10-02

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2012-D-1010] Draft Guidance for Industry on Initial Completeness Assessments for Type II Active Pharmaceutical... certain drug master files, namely, Type II active pharmaceutical ingredient (API) drug master files (DMFs...

  5. Active locking and entanglement in type II optical parametric oscillators

    Science.gov (United States)

    Ruiz-Rivas, Joaquín; de Valcárcel, Germán J.; Navarrete-Benlloch, Carlos

    2018-02-01

    Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.

  6. Human type II pneumocyte chemotactic responses to CXCR3 activation are mediated by splice variant A.

    Science.gov (United States)

    Ji, Rong; Lee, Clement M; Gonzales, Linda W; Yang, Yi; Aksoy, Mark O; Wang, Ping; Brailoiu, Eugen; Dun, Nae; Hurford, Matthew T; Kelsen, Steven G

    2008-06-01

    Chemokine receptors control several fundamental cellular processes in both hematopoietic and structural cells, including directed cell movement, i.e., chemotaxis, cell differentiation, and proliferation. We have previously demonstrated that CXCR3, the chemokine receptor expressed by Th1/Tc1 inflammatory cells present in the lung, is also expressed by human airway epithelial cells. In airway epithelial cells, activation of CXCR3 induces airway epithelial cell movement and proliferation, processes that underlie lung repair. The present study examined the expression and function of CXCR3 in human alveolar type II pneumocytes, whose destruction causes emphysema. CXCR3 was present in human fetal and adult type II pneumocytes as assessed by immunocytochemistry, immunohistochemistry, and Western blotting. CXCR3-A and -B splice variant mRNA was present constitutively in cultured type II cells, but levels of CXCR3-B greatly exceeded CXCR3-A mRNA. In cultured type II cells, I-TAC, IP-10, and Mig induced chemotaxis. Overexpression of CXCR3-A in the A549 pneumocyte cell line produced robust chemotactic responses to I-TAC and IP-10. In contrast, I-TAC did not induce chemotactic responses in CXCR3-B and mock-transfected cells. Finally, I-TAC increased cytosolic Ca(2+) and activated the extracellular signal-regulated kinase, p38, and phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B kinases only in CXCR3-A-transfected cells. These data indicate that the CXCR3 receptor is expressed by human type II pneumocytes, and the CXCR3-A splice variant mediates chemotactic responses possibly through Ca(2+) activation of both mitogen-activated protein kinase and PI 3-kinase signaling pathways. Expression of CXCR3 in alveolar epithelial cells may be important in pneumocyte repair from injury.

  7. Active galactic nuclei

    CERN Document Server

    Beckmann, Volker

    2012-01-01

    This AGN textbook includes phenomena based on new results in the X-Ray domain from new telescopes such as Chandra and XMM Newton not mentioned in any other book. Furthermore, it considers also the Fermi Gamma Ray Space Telescope with its revolutionary advances of unprecedented sensitivity, field of view and all-sky monitoring. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. The book gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy d

  8. Creatine Kinase Activity in Patients with Diabetes Mellitus Type I and Type II

    Directory of Open Access Journals (Sweden)

    Adlija Jevrić-Čaušević

    2006-08-01

    Full Text Available Diabetes mellitus can be looked upon as an array of diseases, all of which exhibit common symptoms. While pathogenesis of IDDM (insulin dependant diabetes mellitus is well understood, the same is not true for diabetes mellitus type II. In the latter case, relative contribution of the two factors (insulin resistance or decreased insulin secretion varies individually, being highly increased in peripheral tissues and strictly dependant on insulin for glucose uptake. Moreover, in patients with diabetes mellitus type II, disbalance at the level of regulation of glucose metabolism as well as lipid metabolism has been noted in skeletal muscles. It is normal to assume that in this type of diabetes, these changes are reflected at the level of total activity of enzyme creatine kinase. This experimental work was performed on a group of 80 regular patients of Sarajevo General Hospital. Forty of those patients were classified as patients with diabetes type I and forty as patients with diabetes type II. Each group of patients was carefully chosen and constituted of equal number of males and females. The same was applied for adequate controls. Concentration of glucose was determined for each patient with GOD method, while activity of creatine kinase was determined with CK-NAC activated kit. Statistical analysis of the results was performed with SPSS software for Windows. Obtained results point out highly expressed differences in enzyme activity between two populations examined. Changes in enzyme activity are more expressed in patients with diabetes type II. Positive correlation between concentration of glucose and serum activity of the enzyme is seen in both categories of diabetic patients which is not the case for the patients in control group. At the same time, correlation between age and type of diabetes does exist . This is not followed at the level of enzyme activity or concentration of glucose.

  9. Arthrogenicity of type II collagen monoclonal antibodies associated with complement activation and antigen affinity

    OpenAIRE

    Koobkokkruad, Thongchai; Kadotani, Tatsuya; Hutamekalin, Pilaiwanwadee; Mizutani, Nobuaki; Yoshino, Shin

    2011-01-01

    Abstract Background The collagen antibody-induced arthritis (CAIA) model, which employs a cocktail of monoclonal antibodies (mAbs) to type II collagen (CII), has been widely used for studying the pathogenesis of autoimmune arthritis. In this model, not all mAbs to CII are capable of inducing arthritis because one of the initial events is the formation of collagen-antibody immune complexes on the cartilage surface or in the synovium, and subsequent activation of the complement by the complexes...

  10. TESTING TESTS ON ACTIVE GALACTIC NUCLEI MICROVARIABILITY

    International Nuclear Information System (INIS)

    De Diego, Jose A.

    2010-01-01

    Literature on optical and infrared microvariability in active galactic nuclei (AGNs) reflects a diversity of statistical tests and strategies to detect tiny variations in the light curves of these sources. Comparison between the results obtained using different methodologies is difficult, and the pros and cons of each statistical method are often badly understood or even ignored. Even worse, improperly tested methodologies are becoming more and more common, and biased results may be misleading with regard to the origin of the AGN microvariability. This paper intends to point future research on AGN microvariability toward the use of powerful and well-tested statistical methodologies, providing a reference for choosing the best strategy to obtain unbiased results. Light curves monitoring has been simulated for quasars and for reference and comparison stars. Changes for the quasar light curves include both Gaussian fluctuations and linear variations. Simulated light curves have been analyzed using χ 2 tests, F tests for variances, one-way analyses of variance and C-statistics. Statistical Type I and Type II errors, which indicate the robustness and the power of the tests, have been obtained in each case. One-way analyses of variance and χ 2 prove to be powerful and robust estimators for microvariations, while the C-statistic is not a reliable methodology and its use should be avoided.

  11. Dichloroacetate Decreases Cell Health and Activates Oxidative Stress Defense Pathways in Rat Alveolar Type II Pneumocytes

    Directory of Open Access Journals (Sweden)

    Alexis Valauri-Orton

    2015-01-01

    Full Text Available Dichloroacetate (DCA is a water purification byproduct that is known to be hepatotoxic and hepatocarcinogenic and to induce peripheral neuropathy and damage macrophages. This study characterizes the effects of the haloacetate on lung cells by exposing rat alveolar type II (L2 cells to 0–24 mM DCA for 6–24 hours. Increasing DCA concentration and the combination of increasing DCA concentration plus longer exposures decrease measures of cellular health. Length of exposure has no effect on oxidative stress biomarkers, glutathione, SOD, or CAT. Increasing DCA concentration alone does not affect total glutathione or its redox ratio but does increase activity in the SOD/CAT oxidative stress defense pathway. These data suggest that alveolar type II cells rely on SOD and CAT more than glutathione to combat DCA-induced stress.

  12. Physical activity in type II Diabetes Mellitus, an effective therapeutic element: review of the clinical impact

    Directory of Open Access Journals (Sweden)

    Pedro Iván Arias-Vázquez

    2015-07-01

    Full Text Available A review was conducted in databases (PubMed, PEDro of type studies clinical trial, cohort study, systematic reviews, meta-analysis and clinical practice guidelines based on evidence they have studied the benefits of physical activity in the prevention , treatment and decreased risk of complications and death in patients with Type II Diabetes Mellitus. Realization regular physical activity is associated with a decreased risk of developing Diabetes Mellitus; likewise was associated with decrease in glycated hemoglobin percentage A1C values. Diabetic patients undergoing high levels of physical activity had decreased risk of complications and death from cardiovascular disease and all causes. At present the scientific evidence on the impact of physical activity in the prevention and treatment of Diabetes Mellitus is solid, so it must be emphasized promoting physical activity as a fundamental part of the therapeutic regimens for this disease.

  13. Searching for dual active galactic nuclei

    Indian Academy of Sciences (India)

    K. Rubinur

    2018-02-09

    Feb 9, 2018 ... Abstract. Binary or dual active galactic nuclei (DAGN) are expected from galaxy formation theories. How- ... cuss results from the multi-frequency Expanded Very .... mid-IR color using WISE observations where they have.

  14. Antiviral activities of Radix Isatidis polysaccharide against type II herpes simplex virus in vitro

    Directory of Open Access Journals (Sweden)

    Chunmei WANG

    2018-03-01

    Full Text Available Abstract This study investigated the antiviral activities of Radix Isatidis polysaccharide (RIP against type II herpes simplex virus (HSV-2 in vitro. RIP was prepared from the Radix Isatidis root. The toxicity of RIP on Vero cells was detected. The direct killing effect of RIP on HSV-2, inhibitory effect of RIP on HSV-2 replication and inhibitory effect of RIP on HSV-2 adsorption were determined. Results showed that, RIP in concentration range of 25-800 mg/L had no toxic effect on Vero cells. RIP with different concentrations could not directly inactivate the HSV-2. The effective rates on inhibition of HSV-2 replication and adsorption in 800 mg/L RIP group were 71.57% and 48.37%, respectively, which were the highest among different groups. In conclusion, RIP has the antiviral effect against HSV-2 in vitro. This effect mainly occurs in inhibiting the virus duplication and adsorption.

  15. Type II thyroplasty changes cortical activation in patients with spasmodic dysphonia.

    Science.gov (United States)

    Tateya, Ichiro; Omori, Koichi; Kojima, Hisayoshi; Naito, Yasushi; Hirano, Shigeru; Yamashita, Masaru; Ito, Juichi

    2015-04-01

    Spasmodic dysphonia (SD) is a complex neurological communication disorder characterized by a choked, strain-strangled vocal quality with voice stoppages in phonation. Its symptoms are exacerbated by situations where communication failures are anticipated, and reduced when talking with animals or small children. Symptoms are also reduced following selected forms of treatment. It is reasonable to assume that surgical alteration reducing symptoms would also alter brain activity, though demonstration of such a phenomenon has not been documented. The objective of this study is to reveal brain activity of SD patients before and after surgical treatment. We performed lateralization thyroplasties on three adductor SD patients and compared pre- and post-operative positron emission tomography recordings made during vocalization. Pre-operatively, cordal supplementary motor area (SMA), bilateral auditory association areas, and thalamus were activated while reading aloud. Such activity was not observed in normal subjects. Type II thyroplasty was performed according to Isshiki's method and the strained voice was significantly reduced or eliminated in all three patients. Post-operative PET showed normal brain activation pattern with a significant decrease in cordal SMA, bilateral auditory association areas and thalamus, and a significant increase in rostral SMA compared with pre-operative recordings. This is the first report showing that treatment to a peripheral organ, which reverses voice symptoms, also reverses dysfunctional patterns of the central nervous system in patients with SD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. QM/MM simulations identify the determinants of catalytic activity differences between type II dehydroquinase enzymes.

    Science.gov (United States)

    Lence, Emilio; van der Kamp, Marc W; González-Bello, Concepción; Mulholland, Adrian J

    2018-05-16

    Type II dehydroquinase enzymes (DHQ2), recognized targets for antibiotic drug discovery, show significantly different activities dependent on the species: DHQ2 from Mycobacterium tuberculosis (MtDHQ2) and Helicobacter pylori (HpDHQ2) show a 50-fold difference in catalytic efficiency. Revealing the determinants of this activity difference is important for our understanding of biological catalysis and further offers the potential to contribute to tailoring specificity in drug design. Molecular dynamics simulations using a quantum mechanics/molecular mechanics potential, with correlated ab initio single point corrections, identify and quantify the subtle determinants of the experimentally observed difference in efficiency. The rate-determining step involves the formation of an enolate intermediate: more efficient stabilization of the enolate and transition state of the key step in MtDHQ2, mainly by the essential residues Tyr24 and Arg19, makes it more efficient than HpDHQ2. Further, a water molecule, which is absent in MtDHQ2 but involved in generation of the catalytic Tyr22 tyrosinate in HpDHQ2, was found to destabilize both the transition state and the enolate intermediate. The quantification of the contribution of key residues and water molecules in the rate-determining step of the mechanism also leads to improved understanding of higher potencies and specificity of known inhibitors, which should aid ongoing inhibitor design.

  17. Secretory activity and cell cycle alteration of alveolar type II cells in the early and late phase after irradiation

    International Nuclear Information System (INIS)

    Willner, Jochen; Vordermark, Dirk; Schmidt, Michael; Gassel, Andreamaria; Flentje, Michael; Wirtz, Hubert

    2003-01-01

    Purpose: Type II cells and the surfactant system have been proposed to play a central role in pathogenesis of radiation pneumonitis. We analyzed the secretory function and proliferation parameters of alveolar type II cells in the early (until 24 h) and late phase (1-5 weeks) after irradiation (RT) in vitro and in vivo. Methods and Materials: Type II cells were isolated from rats according to the method of Dobbs. Stimulation of secretion was induced with terbutaline, adenosine triphosphate (ATP), and 12-O-tetradecanoylphorbol-13-acetate (TPA) for a 2-h period. Determination of secretion was performed using 3 H-labeled phosphatidylcholine. For the early-phase analysis, freshly isolated and adherent type II cells were irradiated in vitro with 9-21 Gy (stepwise increase of 3 Gy). Secretion stimulation was initiated 1, 6, 24, and 48 h after RT. For late-phase analysis, type II cells were isolated 1-5 weeks after 18 Gy whole lung or sham RT. Each experiment was repeated at least fivefold. Flow cytometry was used to determine cell cycle distribution and proliferating cell nuclear antigen index. Results: During the early-phase (in vitro) analysis, we found a normal stimulation of surfactant secretion in irradiated, as well as unirradiated, cells. No change in basal secretion and no dose effect were seen. During the late phase, 1-5 weeks after whole lung RT, we observed enhanced secretory activity for all secretagogues and a small increase in basal secretion in Weeks 3 and 4 (pneumonitis phase) compared with controls. The total number of isolated type II cells, as well as the rate of viable cells, decreased after the second post-RT week. Cell cycle alterations suggesting an irreversible G 2 /M block occurred in the second post-RT week and did not resolve during the observation period. The proliferating cell nuclear antigen index of type II cells from irradiated rats did not differ from that of controls. Conclusion: In contrast to literature data, we observed no direct

  18. Arthrogenicity of type II collagen monoclonal antibodies associated with complement activation and antigen affinity.

    Science.gov (United States)

    Koobkokkruad, Thongchai; Kadotani, Tatsuya; Hutamekalin, Pilaiwanwadee; Mizutani, Nobuaki; Yoshino, Shin

    2011-11-04

    The collagen antibody-induced arthritis (CAIA) model, which employs a cocktail of monoclonal antibodies (mAbs) to type II collagen (CII), has been widely used for studying the pathogenesis of autoimmune arthritis. In this model, not all mAbs to CII are capable of inducing arthritis because one of the initial events is the formation of collagen-antibody immune complexes on the cartilage surface or in the synovium, and subsequent activation of the complement by the complexes induces arthritis, suggesting that a combination of mAbs showing strong ability to bind mouse CII and activate the complement may effectively induce arthritis in mice. In the present study, we examined the relationship between the induction of arthritis by the combination of IgG2a (CII-6 and C2A-12), IgG2b (CII-3, C2B-14 and C2B-16) and IgM (CM-5) subclones of monoclonal antibodies (mAb) of anti-bovine or chicken CII and the ability of mAbs to activate complement and bind mouse CII. DBA/1J mice were injected with several combinations of mAbs followed by lipopolysaccharide. Furthermore, the ability of mAbs to activate the complement and bind mouse CII was examined by ELISA. First, DBA/1J mice were injected with the combined 4 mAbs (CII-3, CII-6, C2B-14, and CM-5) followed by lipopolysaccharide, resulting in moderate arthritis. Excluding one of the mAbs, i.e., using only CII-3, CII-6, and C2B-14, induced greater inflammation of the joints. Next, adding C2A-12 but not C2B-16 to these 3 mAbs produced more severe arthritis. A combination of five clones, consisting of all 5 mAbs, was less effective. Histologically, mice given the newly developed 4-clone cocktail had marked proliferation of synovial tissues, massive infiltration by inflammatory cells, and severe destruction of cartilage and bone. Furthermore, 4 of the 6 clones (CII-3, CII-6, C2B-14, and C2A-12) showed not only a strong cross-reaction with mouse CII but also marked activation of the complement in vitro. The combination of 4 mAbs showing

  19. Arthrogenicity of type II collagen monoclonal antibodies associated with complement activation and antigen affinity

    Directory of Open Access Journals (Sweden)

    Mizutani Nobuaki

    2011-11-01

    Full Text Available Abstract Background The collagen antibody-induced arthritis (CAIA model, which employs a cocktail of monoclonal antibodies (mAbs to type II collagen (CII, has been widely used for studying the pathogenesis of autoimmune arthritis. In this model, not all mAbs to CII are capable of inducing arthritis because one of the initial events is the formation of collagen-antibody immune complexes on the cartilage surface or in the synovium, and subsequent activation of the complement by the complexes induces arthritis, suggesting that a combination of mAbs showing strong ability to bind mouse CII and activate the complement may effectively induce arthritis in mice. In the present study, we examined the relationship between the induction of arthritis by the combination of IgG2a (CII-6 and C2A-12, IgG2b (CII-3, C2B-14 and C2B-16 and IgM (CM-5 subclones of monoclonal antibodies (mAb of anti-bovine or chicken CII and the ability of mAbs to activate complement and bind mouse CII. Methods DBA/1J mice were injected with several combinations of mAbs followed by lipopolysaccharide. Furthermore, the ability of mAbs to activate the complement and bind mouse CII was examined by ELISA. Results First, DBA/1J mice were injected with the combined 4 mAbs (CII-3, CII-6, C2B-14, and CM-5 followed by lipopolysaccharide, resulting in moderate arthritis. Excluding one of the mAbs, i.e., using only CII-3, CII-6, and C2B-14, induced greater inflammation of the joints. Next, adding C2A-12 but not C2B-16 to these 3 mAbs produced more severe arthritis. A combination of five clones, consisting of all 5 mAbs, was less effective. Histologically, mice given the newly developed 4-clone cocktail had marked proliferation of synovial tissues, massive infiltration by inflammatory cells, and severe destruction of cartilage and bone. Furthermore, 4 of the 6 clones (CII-3, CII-6, C2B-14, and C2A-12 showed not only a strong cross-reaction with mouse CII but also marked activation of the

  20. Achilles tendinopathy in elderly subjects with type II diabetes: the role of sport activities.

    Science.gov (United States)

    Abate, Michele; Salini, Vincenzo; Schiavone, Cosima

    2016-04-01

    Exercise is an important therapeutic tool in the management of diabetes in older people. Aim of this study was to assess the relationship among type II diabetes, sport, overweight, and symptomatic Achilles tendinopathy in elderly subjects. Thirty-eight patients suffering from Achilles tendinopathy and thirty-eight controls were enrolled. The prevalence of diabetes and sport practice as well as BMI and Glycated Hemoglobin (HbA1c) values were registered. An ultrasound evaluation of Achilles tendon was performed. Patients showed an increased prevalence of diabetes (42 vs. 13.1 %, p = 0.004), and practice of sport (60.5 vs. 28.9 %, p = 0.0001), and higher BMI values (26.8 ± 3 vs. 24.8 ± 2.3, p = 0.001). Sonographic abnormalities, being diagnostic criteria, were present in all the patients with Achilles tendinopathy, but signs of degeneration were also found in 36.8 % of asymptomatic controls. Symptomatic subjects with diabetes, compared to those without, showed a higher prevalence of severe degeneration (75 vs. 36.3 %, p = 0.01). HbA1c values were significantly lower in sport practitioners, both diabetics and non-diabetics. Moreover, patients practicing sport showed a trend towards lower BMI values, compared to the sedentary counterpart. Sport practice in elderly diabetics provides relevant metabolic advantages, reducing HbA1c and BMI. However, some sport activities (e.g., speed walking, jogging or tennis) can expose to the risk of Achilles tendinopathy. So, sport practice should be encouraged, but practitioners should follow individual training programs and be submitted to periodic sonographic controls.

  1. Quasars, Seyfert galaxies and active galactic nuclei

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1987-01-01

    This chapter is devoted to the spectroscopic methods for analyzing the observed plasma in the nuclei of quasars, Seyfert galazies, and active galactic nuclei. Both the narrow-line region and the broad-line region are discussed. Physical models are presented

  2. Occurrence and activity of a type II CRISPR-Cas system in Lactobacillus gasseri.

    Science.gov (United States)

    Sanozky-Dawes, Rosemary; Selle, Kurt; O'Flaherty, Sarah; Klaenhammer, Todd; Barrangou, Rodolphe

    2015-09-01

    Bacteria encode clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated genes (cas), which collectively form an RNA-guided adaptive immune system against invasive genetic elements. In silico surveys have revealed that lactic acid bacteria harbour a prolific and diverse set of CRISPR-Cas systems. Thus, the natural evolutionary role of CRISPR-Cas systems may be investigated in these ecologically, industrially, scientifically and medically important microbes. In this study, 17 Lactobacillus gasseri strains were investigated and 6 harboured a type II-A CRISPR-Cas system, with considerable diversity in array size and spacer content. Several of the spacers showed similarity to phage and plasmid sequences, which are typical targets of CRISPR-Cas immune systems. Aligning the protospacers facilitated inference of the protospacer adjacent motif sequence, determined to be 5'-NTAA-3' flanking the 3' end of the protospacer. The system in L. gasseri JV-V03 and NCK 1342 interfered with transforming plasmids containing sequences matching the most recently acquired CRISPR spacers in each strain. We report the distribution and function of a native type II-A CRISPR-Cas system in the commensal species L. gasseri. Collectively, these results open avenues for applications for bacteriophage protection and genome modification in L. gasseri, and contribute to the fundamental understanding of CRISPR-Cas systems in bacteria.

  3. Accretion disks in active galactic nuclei

    International Nuclear Information System (INIS)

    Shields, G.A.

    1989-01-01

    Active galactic nuclei (AGN) have taunted astrophysicists for a quarter century. How do these objects produce huge luminosities---in some cases, far outshining our galaxy---from a region perhaps no larger than the solar system? Accretion onto supermassive black holes has been widely considered the best buy in theories of AGN. Much work has gone into accretion disk theory, searches for black holes in galactic nuclei, and observational tests. These efforts have not proved the disk model, but there is progress. Evidence for black holes in the nuclei of nearby galaxies is provided by observations of stellar velocities, and radiation from the disk's hot surface may be observed in the ultraviolet (UV) and neighboring spectral bands. In the review, the author describe some of the recent work on accretion disks in AGN, with an emphasis on points of contact between theory and observation

  4. Active galactic nucleus outflows in galaxy discs

    Science.gov (United States)

    Hartwig, Tilman; Volonteri, Marta; Dashyan, Gohar

    2018-05-01

    Galactic outflows, driven by active galactic nuclei (AGNs), play a crucial role in galaxy formation and in the self-regulated growth of supermassive black holes (BHs). AGN feedback couples to and affects gas, rather than stars, and in many, if not most, gas-rich galaxies cold gas is rotationally supported and settles in a disc. We present a 2D analytical model for AGN-driven outflows in a gaseous disc and demonstrate the main improvements, compared to existing 1D solutions. We find significant differences for the outflow dynamics and wind efficiency. The outflow is energy-driven due to inefficient cooling up to a certain AGN luminosity (˜1043 erg s-1 in our fiducial model), above which the outflow remains momentum-driven in the disc up to galactic scales. We reproduce results of 3D simulations that gas is preferentially ejected perpendicular to the disc and find that the fraction of ejected interstellar medium is lower than in 1D models. The recovery time of gas in the disc, defined as the free-fall time from the radius to which the AGN pushes the ISM at most, is remarkably short, of the order 1 Myr. This indicates that AGN-driven winds cannot suppress BH growth for long. Without the inclusion of supernova feedback, we find a scaling of the BH mass with the halo velocity dispersion of MBH ∝ σ4.8.

  5. Sulfatide-activated type II NKT cells prevent allergic airway inflammation by inhibiting type I NKT cell function in a mouse model of asthma.

    Science.gov (United States)

    Zhang, Guqin; Nie, Hanxiang; Yang, Jiong; Ding, Xuhong; Huang, Yi; Yu, Hongying; Li, Ruyou; Yuan, Zhuqing; Hu, Suping

    2011-12-01

    Asthma is a common chronic inflammatory disease involving many different cell types. Recently, type I natural killer T (NKT) cells have been demonstrated to play a crucial role in the development of asthma. However, the roles of type II NKT cells in asthma have not been investigated before. Interestingly, type I and type II NKT cells have been shown to have opposing roles in antitumor immunity, antiparasite immunity, and autoimmunity. We hypothesized that sulfatide-activated type II NKT cells could prevent allergic airway inflammation by inhibiting type I NKT cell function in asthma. Strikingly, in our mouse model, activation of type II NKT cells by sulfatide administration and adoptive transfer of sulfatide-activated type II NKT cells result in reduced-inflammation cell infiltration in the lung and bronchoalveolar lavage fluid, decreased levels of IL-4 and IL-5 in the BALF; and decreased serum levels of ovalbumin-specific IgE and IgG1. Furthermore, it is found that the activation of sulfatide-reactive type II NKT cells leads to the functional inactivation of type I NKT cells, including the proliferation and cytokine secretion. Our data reveal that type II NKT cells activated by glycolipids, such as sulfatide, may serve as a novel approach to treat allergic diseases and other disorders characterized by inappropriate type I NKT cell activation.

  6. Solar Type II Radio Bursts and IP Type II Events

    Science.gov (United States)

    Cane, H. V.; Erickson, W. C.

    2005-01-01

    We have examined radio data from the WAVES experiment on the Wind spacecraft in conjunction with ground-based data in order to investigate the relationship between the shocks responsible for metric type II radio bursts and the shocks in front of coronal mass ejections (CMEs). The bow shocks of fast, large CMEs are strong interplanetary (IP) shocks, and the associated radio emissions often consist of single broad bands starting below approx. 4 MHz; such emissions were previously called IP type II events. In contrast, metric type II bursts are usually narrowbanded and display two harmonically related bands. In addition to displaying complete dynamic spectra for a number of events, we also analyze the 135 WAVES 1 - 14 MHz slow-drift time periods in 2001-2003. We find that most of the periods contain multiple phenomena, which we divide into three groups: metric type II extensions, IP type II events, and blobs and bands. About half of the WAVES listings include probable extensions of metric type II radio bursts, but in more than half of these events, there were also other slow-drift features. In the 3 yr study period, there were 31 IP type II events; these were associated with the very fastest CMEs. The most common form of activity in the WAVES events, blobs and bands in the frequency range between 1 and 8 MHz, fall below an envelope consistent with the early signatures of an IP type II event. However, most of this activity lasts only a few tens of minutes, whereas IP type II events last for many hours. In this study we find many examples in the radio data of two shock-like phenomena with different characteristics that occur simultaneously in the metric and decametric/hectometric bands, and no clear example of a metric type II burst that extends continuously down in frequency to become an IP type II event. The simplest interpretation is that metric type II bursts, unlike IP type II events, are not caused by shocks driven in front of CMEs.

  7. STELLAR TRANSITS IN ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Béky, Bence; Kocsis, Bence

    2013-01-01

    Supermassive black holes (SMBHs) are typically surrounded by a dense stellar population in galactic nuclei. Stars crossing the line of site in active galactic nuclei (AGNs) produce a characteristic transit light curve, just like extrasolar planets do when they transit their host star. We examine the possibility of finding such AGN transits in deep optical, UV, and X-ray surveys. We calculate transit light curves using the Novikov-Thorne thin accretion disk model, including general relativistic effects. Based on the expected properties of stellar cusps, we find that around 10 6 solar mass SMBHs, transits of red giants are most common for stars on close orbits with transit durations of a few weeks and orbital periods of a few years. We find that detecting AGN transits requires repeated observations of thousands of low-mass AGNs to 1% photometric accuracy in optical, or ∼10% in UV bands or soft X-ray. It may be possible to identify stellar transits in the Pan-STARRS and LSST optical and the eROSITA X-ray surveys. Such observations could be used to constrain black hole mass, spin, inclination, and accretion rate. Transit rates and durations could give valuable information on the circumnuclear stellar clusters as well. Transit light curves could be used to image accretion disks with unprecedented resolution, allowing us to resolve the SMBH silhouette in distant AGNs.

  8. Mutation analysis of peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) and relationships of identified amino acid polymorphisms to Type II diabetes mellitus

    DEFF Research Database (Denmark)

    Ek, J; Andersen, G; Urhammer, S A

    2001-01-01

    This study aimed to investigate if variability in the peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) gene is associated with Type II (non-insulin-dependent) diabetes mellitus.......This study aimed to investigate if variability in the peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) gene is associated with Type II (non-insulin-dependent) diabetes mellitus....

  9. Accretion disks in active galactic nuclei

    International Nuclear Information System (INIS)

    Begelman, M.C.

    1985-01-01

    The innermost regions of the central engines in active galactic nuclei are examined, and it is shown how different modes of accretion with angular momentum may account for the diverse manifestations of activity in the nuclei of galaxies. These modes are subsequently compared with the observed properties of quasars, Type I Seyferts, and radio galaxies. It was found that the qualitative features of an accretion flow orbiting a massive black hole depend principally on the ratio of the actual accretion rate to the Eddington accretion rate. For a value of this ratio much less than one, the flow may become an ion torus supported by gas pressure; for a value much greater than one, the flow traps its radiative output and becomes an inefficient radiation torus. At intermediate values, the flow may settle into a thin accretion disk. 62 references

  10. Optical Variability of Active Galactic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kozłowski, Szymon, E-mail: simkoz@astrouw.edu.pl [Astronomical Observatory, University of Warsaw, Warsaw (Poland)

    2017-09-21

    Variability studies of active galactic nuclei (AGNs) typically use either power spectral density (PSD) and structure function (SF) analyses or direct modeling of light curves with the damped random walk (DRW) and the continuous autoregressive moving average (CARMA) models. A fair fraction of research publications on the subject are flawed, and simply report incorrect results, because they lack a deep understanding of where these methods originate from and what their limitations are. For example, SF analyses typically lack or use a wrong noise subtraction procedure, leading to flat SFs. DRW, on the other hand, can only be used if the experiment length is sufficient, at least ten times the signal decorrelation time scale τ, and if the data show the power-law SF slope of γ ≡ 0.5.

  11. Mood instability in bipolar disorder type I versus type II-continuous daily electronic self-monitoring of illness activity using smartphones

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Ritz, Christian; Frost, Mads

    2015-01-01

    BACKGROUND: A substantial proportion of patients with bipolar disorder remain symptomatic during inter-episode periods, and mood instability is associated with high risk of relapse and hospitalization. Few studies have investigated long-term daily illness activity and none has compared bipolar ty...... with bipolar disorder type I, but despite on-going treatment only for half of the time for patients with bipolar disorder type II. This emphasizes the need for improving treatment strategies for bipolar disorder type II....

  12. Gas Flows in Dual Active Galactic Nuclei

    Science.gov (United States)

    Mueller Sanchez, Francisco; Comerford, Julia M.; Davies, Richard; Treister, Ezequiel; Privon, George C.; Nevin, Becky

    2018-06-01

    Dual Active Galactic Nuclei (AGN) are the Rosetta stone to understand the role of galaxy mergers in triggering nuclear activity and regulating black hole (BH) and galaxy growth. But very little is known about the physical processes required to effectively trigger AGN activity and regulate the growth of the two BHs. The work I will present here characterizes for the first time the properties of the stars, gas (molecular, ionized, and highly-ionized) and dust in all the confirmed dual AGN at z prototypical merger system NGC 6240: vigorous star formation, two AGNs, outflowing winds of ionized gas, rippling dust and gas lanes, and tidal tails. In this galaxy, we observe for the first time a dual outflow of different species of gas: an AGN-driven outflow of highly-ionized gas to the northeast and a starburst-driven outflow of ionized hydrogen to the northwest. This shows that stellar feedback and supermassive black hole feedback can work in tandem to regulate the stellar growth of a galaxy after a merger event. These results open a new door to studies of dual AGN and AGN pairs in general, and enable dual AGN to be used, for the first time, for studies of galaxy evolution.

  13. Environmental properties related to active galactic nuclei

    Science.gov (United States)

    Manzer, Lianne H.

    There continues to be significant controversy regarding the mechanisms responsible for the initiation of activity in galactic nuclei. It is well understood that the non-thermal energy produced by an AGN is due to accretion onto a supermassive black hole. It has not yet been determined, however, what leads particular galaxies to become active. An accurate exploration into what triggers an AGN demands an analysis of a large sample of galaxies across a diverse set of environments. In this work, we investigate possible environmental influences by carrying out a statistical investigation of galaxy groups. Using the catalogue of Yang et al. (2007), in which groups of galaxies containing between 2 and 20 members with redshifts between 0.01 -- 0.20 were taken from the Sloan Digital Sky Survey, we investigate the fraction of active galactic nuclei (AGN) within these groups and compare it to the sample of isolated galaxies also obtained from Yang et al. (2007). After correcting our spectroscopic data for extinction and underlying stellar absorption, we classify the galaxy sample using relevant emission-line ratios. We propose an alternate method for classifying emission-line galaxies, including AGN, which builds upon standard diagnostic utilities used for optical classification and includes uncertainties. Such classification probabilities offer a more robust and consistent method of investigating the effect of group environments with galaxy type. We find our sample to be a fair representation of the local universe by comparing the luminosity function of our entire data set to that of Blanton et al. (2001), Blanton et al. (2003b), and Montero-Dorta & Prada (2009). The evidence also suggests that the luminosity function of galaxies differs between isolated galaxies and galaxies in groups. We find a significant increase in the fraction of AGNs identified in grouped environments. On the other hand, we find a higher fraction of starforming galaxies within isolated systems. We

  14. Dual Active Galactic Nuclei in Nearby Galaxies

    Science.gov (United States)

    Das, Mousumi; Rubinur, Khatun; Karb, Preeti; Varghese, Ashlin; Novakkuni, Navyasree; James, Atul

    2018-04-01

    Galaxy mergers play a crucial role in the formation of massive galaxies and the buildup of their bulges. An important aspect of the merging process is the in-spiral of the supermassive black-holes (SMBHs) to the centre of the merger remnant and the eventual formation of a SMBH binary. If both the SMBHs are accreting they will form a dual or binary active galactic nucleus (DAGN). The final merger remnant is usually very bright and shows enhanced star formation. In this paper we summarise the current sample of DAGN from previous studies and describe methods that can be used to identify strong DAGN candidates from optical and spectroscopic surveys. These methods depend on the Doppler separation of the double peaked AGN emission lines, the nuclear velocity dispersion of the galaxies and their optical/UV colours. We describe two high resolution, radio observations of DAGN candidates that have been selected based on their double peaked optical emission lines (DPAGN). We also examine whether DAGN host galaxies have higher star formation rates (SFRs) compared to merging galaxies that do not appear to have DAGN. We find that the SFR is not higher for DAGN host galaxies. This suggests that the SFRs in DAGN host galaxies is due to the merging process itself and not related to the presence of two AGN in the system.

  15. A climatological study of the relations among solar activity, galactic ...

    Indian Academy of Sciences (India)

    activity, galactic cosmic ray and precipitation on various regions .... mate variations to cosmic rays and the physical- chemical .... For the wavelet spectrum, significance level for each ..... monthly climate for Europe and the globe: The observed.

  16. UNOBSCURED TYPE 2 ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Shi, Yong; Rieke, George H.; Smith, Paul; Donley, Jennifer; Schmidt, Gary; Diamond-Stanic, Aleksandar M.; Rigby, Jane; Hines, Dean

    2010-01-01

    Type 2 active galactic nuclei (AGNs) with intrinsically weak broad emission lines (BELs) would be exceptions to the unified model. After examining a number of proposed candidates critically, we find that the sample is contaminated significantly by objects with BELs of strengths indicating that they actually contain intermediate-type AGNs, plus a few Compton-thick sources as revealed by extremely low ratios of X-ray to nuclear IR luminosities. We develop quantitative metrics that show two (NGC 3147 and NGC 4594) of the remaining candidates to have BELs 2-3 orders of magnitude weaker than those of typical type 1 AGNs. Several more galaxies remain as candidates to have anomalously weak BELs, but this status cannot be confirmed with the existing information. Although the parent sample is poorly defined, the two confirmed objects are well under 1% of its total number of members, showing that the absence of a BEL is possible, but very uncommon in AGN. We evaluate these two objects in detail using multi-wavelength measurements including new IR data obtained with Spitzer and ground-based optical spectropolarimeteric observations. They have little X-ray extinction with N H 21 cm -2 . Their IR spectra show strong silicate emission (NGC 4594) or weak aromatic features on a generally power-law continuum with a suggestion of silicates in emission (NGC 3147). No polarized BEL is detected in NGC 3147. These results indicate that the two unobscured type 2 objects have circumnuclear tori that are approximately face-on. Combined with their X-ray and optical/UV properties, this behavior implies that we have an unobscured view of the nuclei and thus that they have intrinsically weak BELs. We compare their properties with those of the other less-extreme candidates. We then compare the distributions of bolometric luminosities and accretion rates of these objects with theoretical models that predict weak BELs.

  17. Stimulation effects of low dose-rate irradiation on pancreatic antioxidant activity in type II diabetes model mice

    International Nuclear Information System (INIS)

    Nomura, Takaharu; Sakai, Kazuo

    2005-01-01

    The effects of low dose-rate gamma irradiation on the type II diabetes mellitus were investigated in BKS.Cg-+Lepr db /+Lepr db /Jcl (DB mice). Ten-week-old female DB mice (5 mice in each group) were irradiated with gamma ray at 0.35, 0.70, or 1.2 mGy/hr. During the course of the 12 weeks the glucose level slightly increased with little difference between the irradiated and the non-irradiated groups. The plasma insulin concentration decreased within the first 4 weeks in all groups. The level was kept low in the non-irradiated mice; while the insulin level in the irradiated groups showed a tendency to increase. In the 0.70 mGy/hr group the increase was statistically significant after 12 weeks of irradiation. Total activity of SOD, one of antioxidative enzymes, decreased both in non-irradiated and irradiated groups; however the decrease was less in the irradiated groups, especially 0.70 mGy/hr group. In the 0.70 mGy/hr group Mn-SOD activity, one of the components of total SOD activity, increased after 12-week irradiation. A pathological examination of the pancreas revealed that damage to β cells responsible for the secretion of insulin was much less in the 0.70 mGy/hr group compared to that in the non-irradiated group. These results indicated that the low dose-rate irradiation increase the antioxidative capacity in the pancreas to protect β cells from oxidative damage, and the to increase the insulin level. This mechanism would lead the mice to the recovery from the disease and the prolongation of the life span as is demonstrated in our previous report. (author)

  18. Astrophysics of gaseous nebulae and active galactic nuclei

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1989-01-01

    A graduate-level text and reference book on gaseous nebulae and the emission regions in Seyfert galaxies, quasars, and other types of active galactic nuclei (AGN) is presented. The topics discussed include: photoionization equilibrium, thermal equilibrium, calculation of emitted spectrum, comparison of theory with observations, internal dynamics of gaseous nebulae, interstellar dust, regions in the galactic context, planetary nebulae, nova and supernova remnants, diagnostics and physics of AGN, observational results on AGN

  19. Black hole masses in active galactic nuclei

    Science.gov (United States)

    Denney, Kelly D.

    2010-11-01

    We present the complete results from two, high sampling-rate, multi-month, spectrophotometric reverberation mapping campaigns undertaken to obtain either new or improved Hbeta reverberation lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and Hbeta emission line in seven local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) RBLR-L relationship, where our results remove many outliers and significantly reduce the scatter at the low-luminosity end of this relationship. A detailed analysis of the data from our high sampling rate, multi-month reverberation mapping campaign in 2007 reveals that the Hbeta emission region within the BLRs of several nearby AGNs exhibit a variety of kinematic behaviors. Through a velocity-resolved reverberation analysis of the broad Hbeta emission-line flux variations in our sample, we reconstruct velocity-resolved kinematic signals for our entire sample and clearly see evidence for outflowing, infalling, and virialized BLR gas motions in NGC 3227, NGC 3516, and NGC 5548, respectively. Finally, we explore the nature of systematic errors that can arise in measurements of black hole masses from single-epoch spectra of AGNs by utilizing the many epochs available for NGC 5548 and PG1229+204 from reverberation mapping databases. In particular, we examine systematics due to AGN variability, contamination due to constant spectral components (i.e., narrow lines and host galaxy flux), data quality (i.e., signal-to-noise ratio, S/N), and blending of spectral features. We investigate the effect that each of these systematics has on the precision and accuracy of single-epoch masses calculated from two commonly-used line-width measures by comparing these

  20. Inhibition of type I NKT cells by retinoids or following sulfatide-mediated activation of type II NKT cells attenuates alcoholic liver disease

    Science.gov (United States)

    Maricic, Igor; Sheng, Huiming; Marrero, Idania; Seki, Ehikiro; Kisseleva, Tatiana; Chaturvedi, Som; Molle, Natasha; Mathews, K. Stephanie; Gao, Bin; Kumar, Vipin

    2015-01-01

    Innate immune mechanisms leading to liver injury following chronic alcohol ingestion are poorly understood. Natural killer T (NKT) cells, enriched in the liver and comprised of at least two distinct subsets, type I and type II, recognize different lipid antigens presented by CD1d molecules. We have investigated whether differential activation of NKT cell subsets orchestrates inflammatory events leading to alcoholic liver disease (ALD). We found that following chronic plus binge feeding of Lieber-DeCarli liquid diet in male C57BL/6 mice, type I but not type II NKT cells are activated leading to recruitment of inflammatory Gr-1highCD11b+ cells into liver. A central finding is that liver injury following alcohol feeding is dependent upon type I NKT cells. Thus liver injury is significantly inhibited in Jα18−/− mice deficient in type I NKT cells as well as following their inactivation by sulfatide-mediated activation of type II NKT cells. Furthermore we have identified a novel pathway involving all-trans retinoic acid (ATRA) and its receptor RARγ signaling that inhibits type I NKT cells and consequently ALD. A semi-quantitative PCR analysis of hepatic gene expression of some of the key proinflammatory molecules shared in human disease indicated that their upregulation in ALD is dependent upon type I NKT cells. Conclusion Type I but not type II NKT cells become activated following alcohol feeding. Type I NKT cells-induced inflammation and neutrophil recruitment results in liver tissue damage while type II NKT cells protect from injury in ALD. Inhibition of type I NKT cells by retinoids or by sulfatide prevents ALD. Since the CD1d pathway is highly conserved between mice and humans, NKT cell subsets might be targeted for potential therapeutic intervention in ALD. PMID:25477000

  1. The Radius-Luminosity Relationship for Active Galactic Nuclei

    DEFF Research Database (Denmark)

    Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.

    2006-01-01

    We have obtained high resolution images of the central regions of 14 reverberation-mapped active galactic nuclei (AGN) using the Hubble Space Telescope Advanced Camera for Surveys High Resolution Camera to account for host-galaxy starlight contamination of measured AGN luminosities. We measure th...

  2. Studies of relativistic jets in active galactic nuclei with SKA

    NARCIS (Netherlands)

    Agudo, I.; Bottcher, M.; Falcke, H.; Georganopoulos, M.; Ghisellini, G.; Giovannini, G.; Giroletti, M.; Gomez, J.L.; Gurvits, L.; Laing, R.; Lister, M.; Marti, J.M.; Meyer, E.T.; Mizuno, Y.; O'Sullivan, S.; Padovani, P.; Paragi, Z.; Perucho, M.; Schleicher, D.; Stawarz, L.; Vlahakis, N.; Wardle, J.

    2014-01-01

    Relativistic jets in active galactic nuclei (AGN) are among the most powerful astrophysical objects discovered to date. Indeed, jetted AGN studies have been considered a prominent science case for SKA, and were included in several different chapters of the previous SKA Science Book (Carilli &

  3. Calcitonin directly attenuates collagen type II degradation by inhibition of matrix metalloproteinase expression and activity in articular chondrocytes

    DEFF Research Database (Denmark)

    Sondergaard, B C; Wulf, H; Henriksen, K

    2006-01-01

    OBJECTIVE: Calcitonin was recently reported to counter progression of cartilage degradation in an experimental model of osteoarthritis, and the effects were primarily suggested to be mediated by inhibition of subchondral bone resorption. We investigated direct effects of calcitonin on chondrocytes...... by assessing expression of the receptor and pharmacological effects on collagen type II degradation under ex vivo and in vivo conditions. METHODS: Localization of the calcitonin receptor on articular chondrocytes was investigated by immunohistochemistry, and the expression by reverse transcriptase polymerase.......0001-1 microM]. In vivo, cartilage degradation was investigated in ovariectomized (OVX) rats administered with oral calcitonin [2 mg/kg calcitonin] for 9 weeks. RESULTS: The calcitonin receptor was identified in articular chondrocytes by immunohistochemistry and RT-PCR. Calcitonin concentration...

  4. Variability-based active galactic nucleus selection using image subtraction in the SDSS and LSST era

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yumi; Gibson, Robert R.; Becker, Andrew C.; Ivezić, Željko; Connolly, Andrew J.; Ruan, John J.; Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); MacLeod, Chelsea L., E-mail: ymchoi@astro.washington.edu [Physics Department, U.S. Naval Academy, 572 Holloway Road, Annapolis, MD 21402 (United States)

    2014-02-10

    With upcoming all-sky surveys such as LSST poised to generate a deep digital movie of the optical sky, variability-based active galactic nucleus (AGN) selection will enable the construction of highly complete catalogs with minimum contamination. In this study, we generate g-band difference images and construct light curves (LCs) for QSO/AGN candidates listed in Sloan Digital Sky Survey Stripe 82 public catalogs compiled from different methods, including spectroscopy, optical colors, variability, and X-ray detection. Image differencing excels at identifying variable sources embedded in complex or blended emission regions such as Type II AGNs and other low-luminosity AGNs that may be omitted from traditional photometric or spectroscopic catalogs. To separate QSOs/AGNs from other sources using our difference image LCs, we explore several LC statistics and parameterize optical variability by the characteristic damping timescale (τ) and variability amplitude. By virtue of distinguishable variability parameters of AGNs, we are able to select them with high completeness of 93.4% and efficiency (i.e., purity) of 71.3%. Based on optical variability, we also select highly variable blazar candidates, whose infrared colors are consistent with known blazars. One-third of them are also radio detected. With the X-ray selected AGN candidates, we probe the optical variability of X-ray detected optically extended sources using their difference image LCs for the first time. A combination of optical variability and X-ray detection enables us to select various types of host-dominated AGNs. Contrary to the AGN unification model prediction, two Type II AGN candidates (out of six) show detectable variability on long-term timescales like typical Type I AGNs. This study will provide a baseline for future optical variability studies of extended sources.

  5. Fusion-activated Ca(2+ entry: an "active zone" of elevated Ca(2+ during the postfusion stage of lamellar body exocytosis in rat type II pneumocytes.

    Directory of Open Access Journals (Sweden)

    Pika Miklavc

    2010-06-01

    Full Text Available Ca(2+ is essential for vesicle fusion with the plasma membrane in virtually all types of regulated exocytoses. However, in contrast to the well-known effects of a high cytoplasmic Ca(2+ concentration ([Ca(2+](c in the prefusion phase, the occurrence and significance of Ca(2+ signals in the postfusion phase have not been described before.We studied isolated rat alveolar type II cells using previously developed imaging techniques. These cells release pulmonary surfactant, a complex of lipids and proteins, from secretory vesicles (lamellar bodies in an exceptionally slow, Ca(2+- and actin-dependent process. Measurements of fusion pore formation by darkfield scattered light intensity decrease or FM 1-43 fluorescence intensity increase were combined with analysis of [Ca(2+](c by ratiometric Fura-2 or Fluo-4 fluorescence measurements. We found that the majority of single lamellar body fusion events were followed by a transient (t(1/2 of decay = 3.2 s rise of localized [Ca(2+](c originating at the site of lamellar body fusion. [Ca(2+](c increase followed with a delay of approximately 0.2-0.5 s (method-dependent and in the majority of cases this signal propagated throughout the cell (at approximately 10 microm/s. Removal of Ca(2+ from, or addition of Ni(2+ to the extracellular solution, strongly inhibited these [Ca(2+](c transients, whereas Ca(2+ store depletion with thapsigargin had no effect. Actin-GFP fluorescence around fused LBs increased several seconds after the rise of [Ca(2+](c. Both effects were reduced by the non-specific Ca(2+ channel blocker SKF96365.Fusion-activated Ca(2+entry (FACE is a new mechanism that leads to [Ca(2+](c transients at the site of vesicle fusion. Substantial evidence from this and previous studies indicates that fusion-activated Ca(2+ entry enhances localized surfactant release from type II cells, but it may also play a role for compensatory endocytosis and other cellular functions.

  6. The Effects of the Local Environment on Active Galactic Nuclei

    Science.gov (United States)

    Manzer, L. H.; De Robertis, M. M.

    2014-06-01

    There continues to be significant controversy regarding the mechanism(s) responsible for the initiation and maintenance of activity in galactic nuclei. In this paper we will investigate possible environmental triggers of nuclear activity through a statistical analysis of a large sample of galaxy groups. The focus of this paper is to identify active galactic nuclei (AGNs) and other emission-line galaxies in these groups and to compare their frequency with a sample of over 260,000 isolated galaxies from the same catalog. The galaxy groups are taken from the catalog of Yang et al., in which over 20,000 virialized groups of galaxies (2 universe. After correcting emission-line equivalent widths for extinction and underlying Balmer stellar absorption, we classify galaxies in the sample using traditional emission-line ratios, while incorporating measurement uncertainties. We find a significantly higher fraction of AGNs in groups compared with the isolated sample. Likewise, a significantly higher fraction of absorption-line galaxies are found in groups, while a higher fraction of star-forming galaxies prefer isolated environments. Within grouped environments, AGNs and star-forming galaxies are found more frequently in small- to medium-richness groups, while absorption-line galaxies prefer groups with larger richnesses. Groups containing only emission-line galaxies have smaller virial radii, velocity dispersions, and masses compared with those containing only absorption-line galaxies. Furthermore, the AGN fraction increases with decreasing distance to the group centroid, independent of galaxy morphology. Using properties obtained from Galaxy Zoo, there is an increased fraction of AGNs within merging systems, unlike star-forming galaxies. These results provide some indication that the local environment does play a role in initiating activity in galactic nuclei, but it is by no means simple or straightforward.

  7. Similar PDK1-AKT-mTOR pathway activation in balloon cells and dysmorphic neurons of type II focal cortical dysplasia with refractory epilepsy.

    Science.gov (United States)

    Lin, Yuan-xiang; Lin, Kun; Kang, De-zhi; Liu, Xin-xiu; Wang, Xing-fu; Zheng, Shu-fa; Yu, Liang-hong; Lin, Zhang-ya

    2015-05-01

    Dysmorphic neurons and balloon cells constitute the neuropathological hallmarks of type II focal cortical dysplasias (FCDs) with refractory epilepsy. The genesis of these cells may be critical to the histological findings in type II FCD. Recent work has shown enhanced activation of the mTOR cascade in both balloon cells and dysmorphic neurons, suggesting a common pathogenesis for these two neuropathological hallmarks. A direct comparative analysis of balloon cells and dysmorphic neurons might identify a molecular link between balloon cells and dysmorphic neurons. Here, we addressed whether PDK1-AKT-mTOR activation differentiates balloon cells from dysmorphic neurons. We used immunohistochemistry with antibodies against phosphorylated (p)-PDK1 (Ser241), p-AKT (Thr308), p-AKT (Ser473), p-mTOR (Ser2448), p-P70S6K (Thr229), and p-p70S6 kinase (Thr389) in balloon cells compared with dysmorphic neurons. Strong or moderate staining for components of the PDK1-AKT-mTOR signaling pathway was observed in both balloon cells and dysmorphic neurons. However, only a few pyramidal neurons displayed weak staining in control group (perilesional neocortex and histologically normal neocortex). Additionally, p-PDK1 (Ser241) and p-AKT (Thr308) staining in balloon cells were stronger than in dysmorphic neurons, whereas p-P70S6K (Thr229) and p-p70S6 kinase (Thr389) staining in balloon cells was weaker than in dysmorphic neurons. In balloon cells, p-AKT (Ser473) and p-mTOR (Ser2448) staining was comparable with the staining in dysmorphic neurons. Our data support the previously suggested pathogenic relationship between balloon cells and dysmorphic neurons concerning activation of the PDK1-AKT-mTOR, which may play important roles in the pathogenesis of type II FCD. Differential expression of some components of the PDK1-AKT-mTOR pathway between balloon cells and dysmorphic neurons may result from cell-specific gene expression. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Thermal-nonthermal relationships in active galactic nuclei

    International Nuclear Information System (INIS)

    Waard, G.J. de.

    1986-01-01

    This dissertation reports on optical and radio observations of active galactic nuclei, selected on the basis of the presence of dominant narrow (narrow line radio galaxies, Seyfert II galaxies, QSOs) and/or broad (broad line radio galaxies, Seyfert I galaxies, QSOs) optical emission lines in their spectra. Special attention is drawn to possible relationships and physical links between the two regimes responsible for the optical (thermal) and radio (non-thermal) emission. Several projects, each studying such relationships on different angular (and thus linear) scales and at different observational frequencies were conceived with a variety of detection devices. (Auth.)

  9. Preclinical activity of the type II CD20 antibody GA101 (obinutuzumab) compared with rituximab and ofatumumab in vitro and in xenograft models.

    Science.gov (United States)

    Herter, Sylvia; Herting, Frank; Mundigl, Olaf; Waldhauer, Inja; Weinzierl, Tina; Fauti, Tanja; Muth, Gunter; Ziegler-Landesberger, Doris; Van Puijenbroek, Erwin; Lang, Sabine; Duong, Minh Ngoc; Reslan, Lina; Gerdes, Christian A; Friess, Thomas; Baer, Ute; Burtscher, Helmut; Weidner, Michael; Dumontet, Charles; Umana, Pablo; Niederfellner, Gerhard; Bacac, Marina; Klein, Christian

    2013-10-01

    We report the first preclinical in vitro and in vivo comparison of GA101 (obinutuzumab), a novel glycoengineered type II CD20 monoclonal antibody, with rituximab and ofatumumab, the two currently approved type I CD20 antibodies. The three antibodies were compared in assays measuring direct cell death (AnnexinV/PI staining and time-lapse microscopy), complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cell-mediated phagocytosis (ADCP), and internalization. The models used for the comparison of their activity in vivo were SU-DHL4 and RL xenografts. GA101 was found to be superior to rituximab and ofatumumab in the induction of direct cell death (independent of mechanical manipulation required for cell aggregate disruption formed by antibody treatment), whereas it was 10 to 1,000 times less potent in mediating CDC. GA101 showed superior activity to rituximab and ofatumumab in ADCC and whole-blood B-cell depletion assays, and was comparable with these two in ADCP. GA101 also showed slower internalization rate upon binding to CD20 than rituximab and ofatumumab. In vivo, GA101 induced a strong antitumor effect, including complete tumor remission in the SU-DHL4 model and overall superior efficacy compared with both rituximab and ofatumumab. When rituximab-pretreated animals were used, second-line treatment with GA101 was still able to control tumor progression, whereas tumors escaped rituximab treatment. Taken together, the preclinical data show that the glyoengineered type II CD20 antibody GA101 is differentiated from the two approved type I CD20 antibodies rituximab and ofatumumab by its overall preclinical activity, further supporting its clinical investigation. ©2013 AACR.

  10. Electrical tuning of the oscillator strength in type II InAs/GaInSb quantum wells for active region of passively mode-locked interband cascade lasers

    Science.gov (United States)

    Dyksik, Mateusz; Motyka, Marcin; Kurka, Marcin; Ryczko, Krzysztof; Misiewicz, Jan; Schade, Anne; Kamp, Martin; Höfling, Sven; Sęk, Grzegorz

    2017-11-01

    Two designs of active region for an interband cascade laser, based on double or triple GaInSb/InAs type II quantum wells (QWs), were compared with respect to passive mode-locked operation in the mid-infrared range around 4 µm. The layer structure and electron and hole wavefunctions under external electric field were engineered to allow controlling the optical transition oscillator strength and the resulting lifetimes. As a result, the investigated structures can mimic absorber-like and gain-like sections of a mode-locked device when properly polarized with opposite bias. A significantly larger oscillator strength tuning range for triple QWs was experimentally verified by Fourier-transform photoreflectance.

  11. Visibility of Active Galactic Nuclei in the Illustris Simulation

    Science.gov (United States)

    Hutchinson-Smith, Tenley; Kelley, Luke; Moreno, Jorge; Hernquist, Lars; Illustris Collaboration

    2018-01-01

    Active galactic nuclei (AGN) are the very bright, luminous regions surrounding supermassive black holes (SMBH) located at the centers of galaxies. Supermassive black holes are the source of AGN feedback, which occurs once the SMBH reaches a certain critical mass. Almost all large galaxies contain a SMBH, but SMBH binaries are extremely rare. Finding these binary systems are important because it can be a source of gravitational waves if the two SMBH collide. In order to study supermassive black holes, astronomers will often rely on the AGN’s light in order to locate them, but this can be difficult due to the extinction of light caused by the dust and gas surrounding the AGN. My research project focuses on determining the fraction of light we can observe from galactic centers using the Illustris simulation, one of the most advanced cosmological simulations of the universe which was created using a hydrodynamic code and consists of a moving mesh. Measuring the fraction of light observable from galactic centers will help us know what fraction of the time we can observe dual and binary AGN in different galaxies, which would also imply a binary SMBH system. In order to find how much light is being blocked or scattered by the gas and dust surrounding the AGN, we calculated the density of the gas and dust along the lines of sight. I present results including the density of gas along different lines of sight and how it correlates with the image of the galaxy. Future steps include taking an average of the column densities for all the galaxies in Illustris and studying them as a function of galaxy type (before merger, during merger, and post-merger), which will give us information on how this can also affect the AGN luminosity.

  12. Sulfoxide stimulation of chondrogenesis in limb mesenchyme is accompanied by an increase in type II collagen enhancer activity

    International Nuclear Information System (INIS)

    Horton, W.E. Jr.; Higginbotham, J.D.

    1991-01-01

    We have utilized a modification of the limb bud mesenchyme micromass culture system to screen compounds that might stimulate chondrogenesis. Two compounds in the sulfoxide family (methylphenylsulfoxide and p-chlorophenyl methyl sulfoxide) were stimulatory at 10(-2) M and 10(-3) M, respectively; whereas other sulfoxides and organic solvents were not active at these concentrations. In addition, specific growth factors (basic FGF, IGF-I, IGF-II) were not chondroinductive at concentrations that are active in other cell systems. Both sulfoxide compounds stimulated cartilage nodule formation, [ 35 S]sulfate incorporation, and activity of the regulatory sequences of the collagen II gene. In contrast, transforming growth factor beta-1 (10 ng/ml) stimulated sulfate incorporation but produced only a diffuse deposition of cartilage matrix and reduced the ability of the cells to utilize the regulatory sequences of the collagen II gene. The sulfoxides appear to promote the differentiation of limb bud cells to chondrocytes and thus exhibit chondroinductive activity

  13. THE OPTX PROJECT. V. IDENTIFYING DISTANT ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Trouille, L.; Barger, A. J.; Tremonti, C.

    2011-01-01

    The Baldwin, Phillips, and Terlevich emission-line ratio diagnostic ([O III]/Hβ versus [N II]/Hα, hereafter BPT diagram) efficiently separates galaxies whose signal is dominated by star formation (BPT-SF) from those dominated by active galactic nucleus (AGN) activity (BPT-AGN). Yet this BPT diagram is limited to z eff ) = 1.0 +0.4 –0.4 ) and has a high X-ray luminosity to total infrared luminosity ratio. This suggests that, on average, the X-ray signal in BPT-comp is dominated by obscured or low accretion rate AGN activity rather than by star formation, supporting their inclusion in the TBT-AGN regime.

  14. Chlorogenic Acid and Rutin Play a Major Role in the In Vivo Anti-Diabetic Activity of Morus alba Leaf Extract on Type II Diabetic Rats

    Science.gov (United States)

    Hunyadi, Attila; Martins, Ana; Hsieh, Tusty-Jiuan; Seres, Adrienn; Zupkó, István

    2012-01-01

    The leaves of the white mulberry tree (Morus alba L.) are used worldwide in traditional medicine as anti-diabetics. Various constituents of mulberry leaves, such as iminosugars (i.e. 1-deoxynojirimicin), flavonoids and related compounds, polysaccharides, glycopeptides and ecdysteroids, have been reported to exert anti-diabetic activity, but knowledge about their contribution to the overall activity is limited. The objective of the present work was to determine the in vivo anti-diabetic activity of an extract of mulberry leaves (MA), and to examine to what extent three major constituents, chlorogenic acid, rutin and isoquercitrin, might contribute to the observed activity. Quantities of the three constituents of interest in the extract were determined by using HPLC-DAD. Activity was determined by using a type II diabetic rat model. After 11 days of per os administration of 250 or 750 mg/kg of MA or the corresponding amounts of each individual compound, a dose dependent decrease of non-fasting blood glucose levels were found for MA, chlorogenic acid and rutin, but not for isoquercitrin. Based on our results, chlorogenic acid and rutin might account for as much as half the observed anti-diabetic activity of MA, hence they can be considered as excellent markers for the quality control of mulberry products. PMID:23185641

  15. Soluble TGF-β type II receptor gene therapy reduces TGF-β activity in irradiated lung tissue and protects lungs from radiation-induced injury

    International Nuclear Information System (INIS)

    Vujaskovic, Z.; Rabbani, Z.; Zhang, X.; Samulski, T.V.; Li, C.-Y.; Anscher, M.S.

    2003-01-01

    Full text: The objective was to determine whether administration of recombinant human adenoviral vector carrying soluble TGF-β1 type II receptor (TβR-II) gene reduces availability of active TGFβ1 and protects lung from radiation-induced injury. Female Fisher-344 rats were randomized into four groups to receive: 1) Control 2) Adenoviral green fluorescent protein vector (AdGFP) alone 3) Radiation (RT) + Adenoviral vector with TGF-β1 type II receptor gene (AdexTβR-II-Fc) 4) RT alone. Animals were irradiated to right hemithorax using a single dose of 30 Gy. The packaging and production of a recombinant adenovirus carrying the fused human TβR-II-IgG1 Fc gene was achieved by use of the AdEasy system. The treatment vector AdexTbR-II-Fc (1.5*1010 PFU) and control vector AdGFP (1*109 PFU) were injected i.v. 24 hrs after RT. Respiratory rate was measured as an index of pulmonary function weekly for 5 weeks post RT. Structural damage was scored histologically. Immunohistochemistry was performed to identify activated macrophages. ELISA was used to quantify active TGF-β1 in tissue homogenate. Western blot was used to determine TβR-II expression in plasma and lung tissue. Animals receiving treatment vector AdexTbR-II-Fc have elevated plasma levels of soluble TβR-II at 24 and 48 hours after injection. In the RT+AdexTbR-II-Fc group, there was a significant reduction in respiratory rate (p = 0.002) at four weeks after treatment compared to RT alone group. Histology revealed a significant reduction in lung structural damage in animals receiving gene therapy after RT vs RT alone (p=0.0013). There was also a decrease in the number of activated macrophage (p= 0.02) in RT+AdexTbR-II-Fc group vs RT alone. The tissue protein expression of active TGF-β1 was significantly reduced in rats receiving RT+AdexTbR-II-Fc treatment (p<0.05). This study shows the ability of adenovirus mediated soluble TβR-II gene therapy to reduce tissue levels of active TGF-β1 and ameliorate radiation

  16. The effects of the local environment on active galactic nuclei

    International Nuclear Information System (INIS)

    Manzer, L. H.; De Robertis, M. M.

    2014-01-01

    There continues to be significant controversy regarding the mechanism(s) responsible for the initiation and maintenance of activity in galactic nuclei. In this paper we will investigate possible environmental triggers of nuclear activity through a statistical analysis of a large sample of galaxy groups. The focus of this paper is to identify active galactic nuclei (AGNs) and other emission-line galaxies in these groups and to compare their frequency with a sample of over 260,000 isolated galaxies from the same catalog. The galaxy groups are taken from the catalog of Yang et al., in which over 20,000 virialized groups of galaxies (2 ≤ N ≤ 20) with redshifts between 0.01 and 0.20 are from the Sloan Digital Sky Survey. We first investigate the completeness of our data set and find, though biases are a concern particularly at higher redshift, that our data provide a fair representation of the local universe. After correcting emission-line equivalent widths for extinction and underlying Balmer stellar absorption, we classify galaxies in the sample using traditional emission-line ratios, while incorporating measurement uncertainties. We find a significantly higher fraction of AGNs in groups compared with the isolated sample. Likewise, a significantly higher fraction of absorption-line galaxies are found in groups, while a higher fraction of star-forming galaxies prefer isolated environments. Within grouped environments, AGNs and star-forming galaxies are found more frequently in small- to medium-richness groups, while absorption-line galaxies prefer groups with larger richnesses. Groups containing only emission-line galaxies have smaller virial radii, velocity dispersions, and masses compared with those containing only absorption-line galaxies. Furthermore, the AGN fraction increases with decreasing distance to the group centroid, independent of galaxy morphology. Using properties obtained from Galaxy Zoo, there is an increased fraction of AGNs within merging systems

  17. The effects of the local environment on active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Manzer, L. H.; De Robertis, M. M., E-mail: liannemanzer@gmail.com, E-mail: mmdr@yorku.ca [Department of Physics and Astronomy, York University, Toronto, ON M3J 1P3 (Canada)

    2014-06-20

    There continues to be significant controversy regarding the mechanism(s) responsible for the initiation and maintenance of activity in galactic nuclei. In this paper we will investigate possible environmental triggers of nuclear activity through a statistical analysis of a large sample of galaxy groups. The focus of this paper is to identify active galactic nuclei (AGNs) and other emission-line galaxies in these groups and to compare their frequency with a sample of over 260,000 isolated galaxies from the same catalog. The galaxy groups are taken from the catalog of Yang et al., in which over 20,000 virialized groups of galaxies (2 ≤ N ≤ 20) with redshifts between 0.01 and 0.20 are from the Sloan Digital Sky Survey. We first investigate the completeness of our data set and find, though biases are a concern particularly at higher redshift, that our data provide a fair representation of the local universe. After correcting emission-line equivalent widths for extinction and underlying Balmer stellar absorption, we classify galaxies in the sample using traditional emission-line ratios, while incorporating measurement uncertainties. We find a significantly higher fraction of AGNs in groups compared with the isolated sample. Likewise, a significantly higher fraction of absorption-line galaxies are found in groups, while a higher fraction of star-forming galaxies prefer isolated environments. Within grouped environments, AGNs and star-forming galaxies are found more frequently in small- to medium-richness groups, while absorption-line galaxies prefer groups with larger richnesses. Groups containing only emission-line galaxies have smaller virial radii, velocity dispersions, and masses compared with those containing only absorption-line galaxies. Furthermore, the AGN fraction increases with decreasing distance to the group centroid, independent of galaxy morphology. Using properties obtained from Galaxy Zoo, there is an increased fraction of AGNs within merging systems

  18. Space Density Of Optically-Selected Type II Quasars From The SDSS

    Science.gov (United States)

    Reyes, Reinabelle; Zakamska, N. L.; Strauss, M. A.; Green, J.; Krolik, J. H.; Shen, Y.; Richards, G. T.

    2007-12-01

    Type II quasars are luminous Active Galactic Nuclei (AGN) whose central regions are obscured by large amounts of gas and dust. In this poster, we present a catalog of 887 type II quasars with redshifts z<0.83 from the Sloan Digital Sky Survey (SDSS), selected based on their emission lines, and derive the 1/Vmax [OIII] 5007 luminosity function from this sample. Since some objects may not be included in the sample because they lack strong emission lines, the derived luminosity function is only a lower limit. We also derive the [OIII] 5007 luminosity function for a sample of type I (broad-line) quasars in the same redshift range. Taking [OIII] 5007 luminosity as a tracer of intrinsic luminosity in both type I and type II quasars, we obtain lower limits to the type II quasar fraction as a function of [OIII] 5007 luminosity, from L[OIII] = 108.3 to 1010 Lsun, which roughly correspond to bolometric luminosities of 1044 to 1046 erg/s.

  19. Cooling Timescale of Dust Tori in Dying Active Galactic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, Kohei [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Tazaki, Ryo, E-mail: k.ichikawa@astro.columbia.edu [Astronomical Institute, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai 980-8578 (Japan)

    2017-07-20

    We estimate the dust torus cooling timescale once the active galactic nucleus (AGN) is quenched. In a clumpy torus system, once the incoming photons are suppressed, the cooling timescale of one clump from T {sub dust} = 1000 K to several 10 K is less than 10 years, indicating that the dust torus cooling time is mainly governed by the light crossing time of the torus from the central engine. After considering the light crossing time of the torus, the AGN torus emission at 12 μ m becomes over two orders of magnitude fainter within 100 years after the quenching. We also propose that those “dying” AGNs could be found using the AGN indicators with a different physical scale R such as 12 μ m band luminosity tracing AGN torus ( R ∼ 10 pc) and the optical [O iii] λ 5007 emission line tracing narrow line regions ( R = 10{sup 2–4} pc).

  20. Photon losses in cosmic ray acceleration in active galactic nuclei

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1984-01-01

    The usual assumption of the acceleration of ultrahigh energy cosmic rays, greater than or equal to 10 18 eV in quasars, Seyfert galaxies, and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10 20 eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10 13 . Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultrahigh energy cosmic ray 10 20 eV by greater than 10 4 times its energy. Hence, it is unlikely that any reasonable configuration of acceleration can avoid disastrous photon energy loss. A different site for ultrahigh energy cosmic ray acceleration must be found

  1. Molecular Abundances in the Disk of AN Active Galactic Nucleus

    Science.gov (United States)

    Harada, N.; Thompson, T. A.; Herbst, E.

    2011-06-01

    There are galactic nuclei that emit high luminosities L˜1044-46 erg S-1 including luminosity produced by X-rays from high mass accretion onto the central black holes. These nuclei are called active galactic nuclei (AGNs), and they are accompanied by molecular disks. Observations show high abundances of CN and HCN in the disks; the molecules are proposed to be probes of X-ray dominated regions (XDRs) created by the X-rays from AGNs. We have constructed a spatially-dependent chemical-abundance model of the molecular disk in NGC 1068, a typical AGN-dominated galaxy. Recently, new observations of CN and HCN have been made at much higher spatial resolution, and there are also detections of polyatomic molecules such as HC3N, c-C3H2, and C2H. We discuss how these observations and our simulations can help us to better understand the physical conditions, the disk structure, and conditions for star formation within molecular disks, which are still uncertain. We also include a comparison with other types of galaxies such as (ultra-) luminous infrared galaxies. Usero et al.Astronomy and Astrophysics. 419 (897), 2004. Initial results were presented at the International Symposium on Molecular Spectroscopy 2010, RF05 Garcia-Burillo et al. Astronomy and Astrophysics. 519 (2), 2010. Garcia-Burillo et al. Journal of Physics Conference Series, 131 (12031), 2008. Costagliola et al. ArXiv e-print arXiv:1101.2122, 2011. Nakajima et al. Astrophysical Journal Letters 728 (L38), 2008.

  2. Activity of the supermassive black hole at the Galactic center

    International Nuclear Information System (INIS)

    Clavel, Maica

    2014-01-01

    Sagittarius A* is the supermassive black hole at the Galactic center. Due to its proximity, this specimen is an excellent laboratory to study the accretion processes occurring around black holes and to constrain the duty cycle of these objects. Sgr A* is currently extremely faint and despite the detection of daily flares, its luminosity remains at least eight orders of magnitude below its Eddington luminosity, making this specimen one of the least luminous known supermassive black holes. The radiative processes responsible for the daily variations of its luminosity have not been clearly identified yet. We present the results of a multi-wavelength campaign observing Sgr A* simultaneously in X-rays and in the near-infrared, using the XMM-Newton observatory and the VLT/NACO instrument. We studied the spectral variability of Sgr A* using the infrared data we obtained through a spectro-imaging technique. Uncertainties linked to the systematic errors are still large but the first tests applied seem to show that the spectral index of Sgr A* could depend on the black hole luminosity. On longer timescales, we demonstrate that Sgr A* experienced a higher level of activity in the recent past. Indeed, echoes of its past activity can be detected in the molecular material surrounding the black hole. They are traced by a strong signal in the iron fluorescence line at 6.4 keV. We achieved a complete and systematic study of this variable emission detected from the central molecular zone, using Chandra and XMM-Newton observatories. Our results confirm that Sgr A* experienced intense flares in the past few centuries, with a luminosity at least six orders of magnitude higher than its current one. In particular, we highlight for the first time the existence of two distinct transient events of relatively short duration, which are probably due to catastrophic events. These results are the first step needed to include Sgr A*'s activity into a broader understanding of the galactic nuclei

  3. ENSEMBLE VARIABILITY OF NEAR-INFRARED-SELECTED ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Kouzuma, S.; Yamaoka, H.

    2012-01-01

    We present the properties of the ensemble variability V for nearly 5000 near-infrared active galactic nuclei (AGNs) selected from the catalog of Quasars and Active Galactic Nuclei (13th Edition) and the SDSS-DR7 quasar catalog. From three near-infrared point source catalogs, namely, Two Micron All Sky Survey (2MASS), Deep Near Infrared Survey (DENIS), and UKIDSS/LAS catalogs, we extract 2MASS-DENIS and 2MASS-UKIDSS counterparts for cataloged AGNs by cross-identification between catalogs. We further select variable AGNs based on an optimal criterion for selecting the variable sources. The sample objects are divided into subsets according to whether near-infrared light originates by optical emission or by near-infrared emission in the rest frame; and we examine the correlations of the ensemble variability with the rest-frame wavelength, redshift, luminosity, and rest-frame time lag. In addition, we also examine the correlations of variability amplitude with optical variability, radio intensity, and radio-to-optical flux ratio. The rest-frame optical variability of our samples shows negative correlations with luminosity and positive correlations with rest-frame time lag (i.e., the structure function, SF), and this result is consistent with previous analyses. However, no well-known negative correlation exists between the rest-frame wavelength and optical variability. This inconsistency might be due to a biased sampling of high-redshift AGNs. Near-infrared variability in the rest frame is anticorrelated with the rest-frame wavelength, which is consistent with previous suggestions. However, correlations of near-infrared variability with luminosity and rest-frame time lag are the opposite of these correlations of the optical variability; that is, the near-infrared variability is positively correlated with luminosity but negatively correlated with the rest-frame time lag. Because these trends are qualitatively consistent with the properties of radio-loud quasars reported

  4. Case 22:Type II diabetes

    Science.gov (United States)

    Diabetes mellitus is characterized by elevated blood glucose levels. It is composed of two types depending on the pathogenesis. Type I diabetes is characterized by insulin deficiency and usually has its onset during childhood or teenage years. This is also called ketosis-prone diabetes. Type II diab...

  5. Type-II Weyl semimetals.

    Science.gov (United States)

    Soluyanov, Alexey A; Gresch, Dominik; Wang, Zhijun; Wu, QuanSheng; Troyer, Matthias; Dai, Xi; Bernevig, B Andrei

    2015-11-26

    Fermions--elementary particles such as electrons--are classified as Dirac, Majorana or Weyl. Majorana and Weyl fermions had not been observed experimentally until the recent discovery of condensed matter systems such as topological superconductors and semimetals, in which they arise as low-energy excitations. Here we propose the existence of a previously overlooked type of Weyl fermion that emerges at the boundary between electron and hole pockets in a new phase of matter. This particle was missed by Weyl because it breaks the stringent Lorentz symmetry in high-energy physics. Lorentz invariance, however, is not present in condensed matter physics, and by generalizing the Dirac equation, we find the new type of Weyl fermion. In particular, whereas Weyl semimetals--materials hosting Weyl fermions--were previously thought to have standard Weyl points with a point-like Fermi surface (which we refer to as type-I), we discover a type-II Weyl point, which is still a protected crossing, but appears at the contact of electron and hole pockets in type-II Weyl semimetals. We predict that WTe2 is an example of a topological semimetal hosting the new particle as a low-energy excitation around such a type-II Weyl point. The existence of type-II Weyl points in WTe2 means that many of its physical properties are very different to those of standard Weyl semimetals with point-like Fermi surfaces.

  6. THE NATURE OF OPTICALLY DULL ACTIVE GALACTIC NUCLEI IN COSMOS

    International Nuclear Information System (INIS)

    Trump, Jonathan R.; Impey, Chris D.; Gabor, Jared M.; Taniguchi, Yoshi; Nagao, Tohru; Shioya, Yasuhiro; Brusa, Marcella; Civano, Francesca; Elvis, Martin; Kelly, Brandon C.; Huchra, John P.; Jahnke, Knud; Koekemoer, Anton M.; Salvato, Mara; Capak, Peter; Scoville, Nick Z.; Kartaltepe, Jeyhan S.; Lanzuisi, Giorgio; McCarthy, Patrick J.; Maineri, Vincenzo

    2009-01-01

    We present infrared, optical, and X-ray data of 48 X-ray bright, optically dull active galactic nuclei (AGNs) in the COSMOS field. These objects exhibit the X-ray luminosity of an AGN but lack broad and narrow emission lines in their optical spectrum. We show that despite the lack of optical emission lines, most of these optically dull AGNs are not well described by a typical passive red galaxy spectrum: instead they exhibit weak but significant blue emission like an unobscured AGN. Photometric observations over several years additionally show significant variability in the blue emission of four optically dull AGNs. The nature of the blue and infrared emission suggest that the optically inactive appearance of these AGNs cannot be caused by obscuration intrinsic to the AGNs. Instead, up to ∼70% of optically dull AGNs are diluted by their hosts, with bright or simply edge-on hosts lying preferentially within the spectroscopic aperture. The remaining ∼30% of optically dull AGNs have anomalously high f X /f O ratios and are intrinsically weak, not obscured, in the optical. These optically dull AGNs are best described as a weakly accreting AGN with a truncated accretion disk from a radiatively inefficient accretion flow.

  7. Probing dark matter with active galactic nuclei jets

    International Nuclear Information System (INIS)

    Gorchtein, Mikhail; Profumo, Stefano; Ubaldi, Lorenzo

    2010-01-01

    We study the possibility of detecting a signature of particle dark matter in the spectrum of gamma-ray photons from active galactic nuclei (AGNs) resulting from the scattering of high-energy particles in the AGN jet off of dark matter particles. We consider particle dark matter models in the context of both supersymmetry and universal extra dimensions , and we present the complete lowest-order calculation for processes where a photon is emitted in dark matter-electron and/or dark matter-proton scattering, where electrons and protons belong to the AGN jet. We find that the process is dominated by a resonance whose energy is dictated by the particle spectrum in the dark matter sector (neutralino and selectron for the case of supersymmetry, Kaluza-Klein photon and electron for universal extra dimensions ). The resulting gamma-ray spectrum exhibits a very characteristic spectral feature, consisting of a sharp break to a hard power-law behavior. Although the normalization of the gamma-ray flux depends strongly on assumptions on both the AGN jet geometry, composition and particle spectrum as well as on the particle dark matter model and density distribution, we show that for realistic parameters choices, and for two prominent nearby AGNs (Centaurus A and M87), the detection of this effect is in principle possible. Finally, we compare our predictions and results with recent gamma-ray observations from the Fermi, H.E.S.S., and VERITAS telescopes.

  8. Diffuse γ-ray emission from misaligned active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Di Mauro, M.; Donato, F. [Physics Department, Torino University, and Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via Giuria 1, I-10125 Torino (Italy); Calore, F. [II. Institute for Theoretical Physics, University of Hamburg, Luruper Chaussee 149, D-22761 Hamburg (Germany); Ajello, M. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Latronico, L., E-mail: donato@to.infn.it [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, via Giuria 1, I-10125 Torino (Italy)

    2014-01-10

    Active galactic nuclei (AGNs) with jets seen at small viewing angles are the most luminous and abundant objects in the γ-ray sky. AGNs with jets misaligned along the line of sight appear fainter in the sky but are more numerous than the brighter blazars. We calculate the diffuse γ-ray emission due to the population of misaligned AGNs (MAGNs) unresolved by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi). A correlation between the γ-ray luminosity and the radio-core luminosity is established and demonstrated to be physical by statistical tests, as well as compatible with upper limits based on Fermi-LAT data for a large sample of radio-loud MAGNs. We constrain the derived γ-ray luminosity function by means of the source-count distribution of the radio galaxies detected by the Fermi-LAT. We finally calculate the diffuse γ-ray flux due to the whole MAGN population. Our results demonstrate that MAGNs can contribute from 10% up to nearly the entire measured isotropic gamma-ray background. We evaluate a theoretical uncertainty on the flux of almost an order of magnitude.

  9. VARIABILITY IN ACTIVE GALACTIC NUCLEI FROM PROPAGATING TURBULENT RELATIVISTIC JETS

    Energy Technology Data Exchange (ETDEWEB)

    Pollack, Maxwell; Pauls, David; Wiita, Paul J., E-mail: wiitap@tcnj.edu [Department of Physics, The College of New Jersey P.O. Box 7718, Ewing, NJ 08628-0718 (United States)

    2016-03-20

    We use the Athena hydrodynamics code to model propagating two-dimensional relativistic jets as approximations to the growth of radio-loud active galactic nuclei for various input jet velocities and jet-to-ambient matter density ratios. Using results from these simulations we estimate the changing synchrotron emission by summing the fluxes from a vertical strip of zones behind the reconfinement shock, which is nearly stationary, and from which a substantial portion of the flux variability should arise. We explore a wide range of timescales by considering two light curves from each simulation; one uses a relativistic turbulence code with bulk velocities taken from our simulations as input, while the other uses the bulk velocity data to compute fluctuations caused by variations in the Doppler boosting due to changes in the direction and the speed of the flow through all zones in the strip. We then calculate power spectral densities (PSDs) from the light curves for both turbulent and bulk velocity origins for variability. The range of the power-law slopes of the PSDs for the turbulence induced variations is −1.8 to −2.3, while for the bulk velocity produced variations this range is −2.1 to −2.9; these are in agreement with most observations. When superimposed, these power spectra span a very large range in frequency (about five decades), with the turbulent fluctuations yielding most of the shorter timescale variations and the bulk flow changes dominating the longer periods.

  10. MERGERS IN DOUBLE-PEAKED [O III] ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Fu Hai; Djorgovski, S. G.; Myers, Adam D.; Yan Lin

    2011-01-01

    As a natural consequence of galaxy mergers, binary active galactic nuclei (AGNs) should be commonplace. Nevertheless, observational confirmations are rare, especially for binaries with separations less than 10 kpc. Such a system may show two sets of narrow emission lines in a single spectrum owing to the orbital motion of the binary. We have obtained high-resolution near-infrared images of 50 double-peaked [O III]λ5007 AGNs with the Keck II laser guide star adaptive optics system. The Sloan Digital Sky Survey sample is compiled from the literature and consists of 17 type-1 AGNs between 0.18 BH -σ * relation because of overestimated stellar velocity dispersions, illustrating the importance of removing mergers from the samples defining the M BH -σ * relations. Finally, we find that the emission-line properties are indistinguishable for spatially resolved and unresolved sources, emphasizing that scenarios involving a single AGN can produce the same double-peaked line profiles and they account for at least 70% of the double-peaked [O III] AGNs.

  11. Ultrafast Outflows: Galaxy-scale Active Galactic Nucleus Feedback

    Science.gov (United States)

    Wagner, A. Y.; Umemura, M.; Bicknell, G. V.

    2013-01-01

    We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two-phase ISM consisting of dense clouds embedded in a tenuous, hot, hydrostatic medium. The outflow floods through the intercloud channels, sweeps up the hot ISM, and ablates and disperses the dense clouds. The momentum of the UFO is primarily transferred to the dense clouds via the ram pressure in the channel flow, and the wind-blown bubble evolves in the energy-driven regime. Any dependence on UFO opening angle disappears after the first interaction with obstructing clouds. On kpc scales, therefore, feedback by UFOs operates similarly to feedback by relativistic AGN jets. Negative feedback is significantly stronger if clouds are distributed spherically rather than in a disk. In the latter case, the turbulent backflow of the wind drives mass inflow toward the central black hole. Considering the common occurrence of UFOs in AGNs, they are likely to be important in the cosmological feedback cycles of galaxy formation.

  12. VARIABILITY IN ACTIVE GALACTIC NUCLEI FROM PROPAGATING TURBULENT RELATIVISTIC JETS

    International Nuclear Information System (INIS)

    Pollack, Maxwell; Pauls, David; Wiita, Paul J.

    2016-01-01

    We use the Athena hydrodynamics code to model propagating two-dimensional relativistic jets as approximations to the growth of radio-loud active galactic nuclei for various input jet velocities and jet-to-ambient matter density ratios. Using results from these simulations we estimate the changing synchrotron emission by summing the fluxes from a vertical strip of zones behind the reconfinement shock, which is nearly stationary, and from which a substantial portion of the flux variability should arise. We explore a wide range of timescales by considering two light curves from each simulation; one uses a relativistic turbulence code with bulk velocities taken from our simulations as input, while the other uses the bulk velocity data to compute fluctuations caused by variations in the Doppler boosting due to changes in the direction and the speed of the flow through all zones in the strip. We then calculate power spectral densities (PSDs) from the light curves for both turbulent and bulk velocity origins for variability. The range of the power-law slopes of the PSDs for the turbulence induced variations is −1.8 to −2.3, while for the bulk velocity produced variations this range is −2.1 to −2.9; these are in agreement with most observations. When superimposed, these power spectra span a very large range in frequency (about five decades), with the turbulent fluctuations yielding most of the shorter timescale variations and the bulk flow changes dominating the longer periods

  13. Bubbles, jets, and clouds in active galactic nuclei

    International Nuclear Information System (INIS)

    Smith, M.D.; Smarr, L.; Norman, M.L.; Wilson, J.R.

    1983-01-01

    The Blandford and Reese 1974 fluid twin-exhaust model for jet formation is thoroughly investigated. We perform detailed analytic calculations of all aspects of the cavity-nozzle structures for the nonrelativistic case: the preshock flow, the central shock, cavity flow, and the nozzle. Our analytic results are in excellent agreement with recent sophisticated numerical calculations. We find that for a given central confining gas cloud, only a finite range of jet powers is possible. The sound speed ratio between cavity and cloud must be less than 30. Central masses of approx.10 9 M/sub sun/ within 1 pc are necessary for high-powered (10 46 ergs s -1 ) extragalactic jets. For a fixed confining cloud sound speed C 0 , there are three regimes determined by the central engine's luminosity. For low luminosity, a stream of bubbles emerges; for a middle range of luminosities, a jet forms; for too high a luminosity, large clouds are emitted. In the jet regime we find that L/sub j/approx.C 0 5 . The critical dependence of jet power on confining cloud sound speed enables a schematic picture for active galactic nuclei to be proposed. Seyfert galaxies and quasars are placed in the bubble regime. Variable compact radio sources reach the cloud regime. Evolutionary paths are suggested and may provide an indirect test for this picture

  14. Optical monitoring of Active Galactic Nuclei from ARIES

    Science.gov (United States)

    Gopal-Krishna; Wiita, Paul Joseph

    2018-04-01

    This overview provides a historical perspective highlighting the pioneering role which the fairly modest observational facilities of ARIES have played since the 1990s in systematically characterizing the optical variability on hour-like time scale (intra-night optical variability, or INOV) of several major types of high-luminosity Active Galactic Nuclei (AGN). Such information was previously available only for blazars. Similar studies have since been initiated in at least a dozen countries, giving a boost to AGN variability research. Our work has, in particular, provided strong indication that mild INOV occurs in radio-quiet QSOs (amplitude up to 3 – 5 % and duty cycle 10%) and, moreover, has demonstrated that similarly mild INOV is exhibited even by the vast majority of radio-loud quasars which possess powerful relativistic jets (even including many that are beamed towards us). The solitary outliers are blazars, the tiny strongly polarized subset of powerful AGN, which frequently exhibit a pronounced INOV. Among the blazars, BL Lac objects often show a bluer-when-brighter chromatic behavior, while the flat spectrum radio quasars seem not to. Quantifying any differences of INOV among the major subclasses of non-blazar type AGNs will require dedicated monitoring programs using 2 - 3 metre class telescopes.

  15. ULTRAFAST OUTFLOWS: GALAXY-SCALE ACTIVE GALACTIC NUCLEUS FEEDBACK

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, A. Y.; Umemura, M. [Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 (Japan); Bicknell, G. V., E-mail: ayw@ccs.tsukuba.ac.jp [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia)

    2013-01-20

    We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two-phase ISM consisting of dense clouds embedded in a tenuous, hot, hydrostatic medium. The outflow floods through the intercloud channels, sweeps up the hot ISM, and ablates and disperses the dense clouds. The momentum of the UFO is primarily transferred to the dense clouds via the ram pressure in the channel flow, and the wind-blown bubble evolves in the energy-driven regime. Any dependence on UFO opening angle disappears after the first interaction with obstructing clouds. On kpc scales, therefore, feedback by UFOs operates similarly to feedback by relativistic AGN jets. Negative feedback is significantly stronger if clouds are distributed spherically rather than in a disk. In the latter case, the turbulent backflow of the wind drives mass inflow toward the central black hole. Considering the common occurrence of UFOs in AGNs, they are likely to be important in the cosmological feedback cycles of galaxy formation.

  16. ULTRAFAST OUTFLOWS: GALAXY-SCALE ACTIVE GALACTIC NUCLEUS FEEDBACK

    International Nuclear Information System (INIS)

    Wagner, A. Y.; Umemura, M.; Bicknell, G. V.

    2013-01-01

    We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two-phase ISM consisting of dense clouds embedded in a tenuous, hot, hydrostatic medium. The outflow floods through the intercloud channels, sweeps up the hot ISM, and ablates and disperses the dense clouds. The momentum of the UFO is primarily transferred to the dense clouds via the ram pressure in the channel flow, and the wind-blown bubble evolves in the energy-driven regime. Any dependence on UFO opening angle disappears after the first interaction with obstructing clouds. On kpc scales, therefore, feedback by UFOs operates similarly to feedback by relativistic AGN jets. Negative feedback is significantly stronger if clouds are distributed spherically rather than in a disk. In the latter case, the turbulent backflow of the wind drives mass inflow toward the central black hole. Considering the common occurrence of UFOs in AGNs, they are likely to be important in the cosmological feedback cycles of galaxy formation.

  17. Optical spectral properties of active galactic nuclei and quasars

    International Nuclear Information System (INIS)

    Yee, H.K.C.

    1981-01-01

    Four separate investigations dealing with the properties of optical continuum and emission-lines of active galactic nuclei (AGN) and quasars are presented. Multichannel scans of 3CR radio galaxies are decomposed by using a two-component model-an elliptical galaxy and a power-law nonthermal component. It is found that there is a strong correlation between the luminosity of the power-law component and the strength of the Balmer emission-lines. In most cases, by extrapolating to the Lyman continuum, the power-law models derived provide enough ionizing radiation to account for the Balmer line strengths. Extending the study of radio galaxies to include Seyfert galaxies and quasars, it is found that there is a strong continuity between broad-line AGN's and quasars in terms of similarities in the correlations between line luminosities and nonthermal continuum luminosity. Next, a study of the variability of absolute optical energy distribution and emission-lines of the N-galaxies 3C382 and 3C390.3 is made. Lastly, a preliminary study of surface photometry of Markarian Seyfert galaxies are presented. It is found that the properties of the underlying galaxies such as scale-length and surface brightness of the disk, color, and total brightness, do not depart systematically from those of luminous normal spiral galaxies

  18. Hydrogen protects against hyperoxia-induced apoptosis in type II alveolar epithelial cells via activation of PI3K/Akt/Foxo3a signaling pathway.

    Science.gov (United States)

    Wu, Dan; Liang, Mulin; Dang, Hongxing; Fang, Fang; Xu, Feng; Liu, Chengjun

    2018-01-08

    Oxidative stress is regarded as a key regulator in the pathogenesis of prolonged hyperoxia-induced lung injury, which causes injury to alveolar epithelial cells and eventually leads to development of bronchopulmonary dysplasia (BPD). Many studies have shown that hydrogen has a protective effect in a variety of cells. However, the mechanisms by which hydrogen rescues cells from damage due to oxidative stress in BPD remains to be fully elucidated. This study sought to evaluate the effects of hydrogen on hyperoxia-induced lung injury and to investigate the underlying mechanism. Primary type II alveolar epithelial cells (AECIIs) were divided into four groups: control (21% oxygen), hyperoxia (95% oxygen), hyperoxia + hydrogen, and hyperoxia + hydrogen + LY294002 (a PI3K/Akt inhibitor). Proliferation and apoptosis of AECIIs were assessed using MTS assay and flow cytometry (FCM), respectively. Gene and protein expression were detected by quantitative polymerase chain reaction (q-PCR) and western blot analysis. Stimulation with hyperoxia decreased the expression of P-Akt, P- FoxO3a, cyclinD1 and Bcl-2. Hyperoxic conditions increased levels of Bim, Bax, and Foxo3a, which induced proliferation restriction and apoptosis of AECIIs. These effects of hyperoxia were reversed with hydrogen pretreatment. Furthermore, the protective effects of hydrogen were abrogated by PI3K/Akt inhibitor LY294002. The results indicate that hydrogen protects AECIIs from hyperoxia-induced apoptosis by inhibiting apoptosis factors and promoting the expression of anti-apoptosis factors. These effects were associated with activation of the PI3K/Akt/FoxO3a pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Type I and type II crustins from Penaeus monodon, genetic variation and antimicrobial activity of the most abundant crustinPm4.

    Science.gov (United States)

    Donpudsa, Suchao; Visetnan, Suwattana; Supungul, Premruethai; Tang, Sureerat; Tassanakajon, Anchalee; Rimphanitchayakit, Vichien

    2014-11-01

    An antimicrobial protein, crustin, is involved in the innate immunity of crustacean by defending the host directly against the microbial pathogens. By data mining the Penaeus monodon EST database, two type I crustins, carcininPm1 and 2, and ten type II crustins, crustinPm1-10, were identified. The abundant crustins were crustinPm1, 4 and 7, each with variation in the length of Gly-rich repeat among its members. A few crustinPm1, 4 and 7 with deletion in the Cys-rich region were also observed. Furthermore, the crustinPm4 with the longest N-terminal Gly-rich region was characterized. The crustinPm4 allelic genes were expressed mainly from the hemocytes. Its expression was up-regulated readily by WSSV infection and gradually decreased to normal level afterwards. The recombinant crustinPm4-1 (rcrustinPm4-1) isoform was produced using the Escherichia coli expression system and tested for its antimicrobial activity. The rcrustinPm4-1 was able to inhibit the growth of a Gram-positive bacterium, Bacillus megaterium but not Bacillus subtilis, Micrococcus luteus and Staphylococcus aureus. It also inhibited the growth of two Gram-negative bacteria, E. coli 363 and Vibrio harveyi 639 at lower potency. The rcrustinPm4-1 affected the WSSV infection because the expression of an intermediate early gene ie1 in WSSV-infected hemocyte cell culture was reduced. It was shown further that the rcrustinPm4-1 could delay by about one and a half days the manifestation of disease by WSSV. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Superb hydroxyl radical-mediated biocidal effect induced antibacterial activity of tuned ZnO/chitosan type II heterostructure under dark

    International Nuclear Information System (INIS)

    Podder, Soumik; Halder, Suman; Roychowdhury, Anirban; Das, Dipankar; Ghosh, Chandan Kr.

    2016-01-01

    generation in ZnO NP and hole transfer from CS for the first time, and a heterostructure of type II was proposed.

  1. Superb hydroxyl radical-mediated biocidal effect induced antibacterial activity of tuned ZnO/chitosan type II heterostructure under dark

    Science.gov (United States)

    Podder, Soumik; Halder, Suman; Roychowdhury, Anirban; Das, Dipankar; Ghosh, Chandan Kr.

    2016-10-01

    hole transfer from CS for the first time, and a heterostructure of type II was proposed.

  2. Superb hydroxyl radical-mediated biocidal effect induced antibacterial activity of tuned ZnO/chitosan type II heterostructure under dark

    Energy Technology Data Exchange (ETDEWEB)

    Podder, Soumik [Jadavpur University, School of Materials Science and Nanotechnology (India); Halder, Suman [Jadavpur University, Department of Pharmaceutical Technology (India); Roychowdhury, Anirban; Das, Dipankar [Kolkata Centre, UGC-DAE Consortium for Scientific Research (India); Ghosh, Chandan Kr., E-mail: chandu-ju@yahoo.co.in [Jadavpur University, School of Materials Science and Nanotechnology (India)

    2016-10-15

    plausible mechanism was hypothesized focusing on hole generation in ZnO NP and hole transfer from CS for the first time, and a heterostructure of type II was proposed.

  3. Light echoes - Type II supernovae

    International Nuclear Information System (INIS)

    Schaefer, B.E.

    1987-01-01

    Type II supernovae (SNs) light curves show a remarkable range of shapes. Data have been collected for the 12 Type II SNs that have light curve information for more than four months past maximum. Contrary to previous reports, it is found that (1) the decay rate after 100 days past maximum varies by almost an order of magnitude and (2) the light curve shapes are not bimodally distributed, but actually form a continuum. In addition, it is found that the extinctions to the SNs are related to the light curve shapes. This implies that the absorbing dust is local to the SNs. The dust is likely to be part of a circumstellar shell emitted by the SN progenitor that Dwek (1983) has used to explain infrared echoes. The optical depth of the shell can get quite large. In such cases, it is found that the photons scattered and delayed by reflection off dust grains will dominate the light curve several months after peak brightness. This light echo offers a straightforward explanation of the diversity of Type II SN light curves. 22 references

  4. Emission line galaxies and active galactic nuclei in WINGS clusters

    Science.gov (United States)

    Marziani, P.; D'Onofrio, M.; Bettoni, D.; Poggianti, B. M.; Moretti, A.; Fasano, G.; Fritz, J.; Cava, A.; Varela, J.; Omizzolo, A.

    2017-03-01

    We present the analysis of the emission line galaxies members of 46 low-redshift (0.04 employing diagnostic diagrams. We examined the emission line properties and frequencies of star-forming galaxies, transition objects, and active galactic nuclei (AGNs: LINERs and Seyferts), unclassified galaxies with emission lines, and quiescent galaxies with no detectable line emission. A deficit of emission line galaxies in the cluster environment is indicated by both a lower frequency, and a systematically lower Balmer emission line equivalent width and luminosity with respect to control samples; this implies a lower amount of ionized gas per unit mass and a lower star formation rate if the source is classified as Hii region. A sizable population of transition objects and of low-luminosity LINERs (≈ 10-20% of all emission line galaxies) are detected among WINGS cluster galaxies. These sources are a factor of ≈1.5 more frequent, or at least as frequent, as in control samples with respect to Hii sources. Transition objects and LINERs in clusters are most affected in terms ofline equivalent width by the environment and appear predominantly consistent with so-called retired galaxies. Shock heating can be a possible gas excitation mechanism that is able to account for observed line ratios. Specific to the cluster environment, we suggest interaction between atomic and molecular gas and the intracluster medium as a possible physical cause of line-emitting shocks. The data whose description is provided in Table B.1, and emission line catalog of the WINGS database are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A83

  5. Spatially Offset Active Galactic Nuclei. II. Triggering in Galaxy Mergers

    Energy Technology Data Exchange (ETDEWEB)

    Barrows, R. Scott; Comerford, Julia M. [Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, Boulder, CO 80309 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Pooley, David, E-mail: Robert.Barrows@Colorado.edu [Department of Physics and Astronomy, Trinity University, San Antonio, TX 78212 (United States)

    2017-04-01

    Galaxy mergers are likely to play a role in triggering active galactic nuclei (AGNs), but the conditions under which this process occurs are poorly understood. In Paper I, we constructed a sample of spatially offset X-ray AGNs that represent galaxy mergers hosting a single AGN. In this paper, we use our offset AGN sample to constrain the parameters that affect AGN observability in galaxy mergers. We also construct dual-AGN samples with similar selection properties for comparison. We find that the offset AGN fraction shows no evidence for a dependence on AGN luminosity, while the dual-AGN fractions show stronger evidence for a positive dependence, suggesting that the merger events forming dual AGNs are more efficient at instigating accretion onto supermassive black holes than those forming offset AGNs. We also find that the offset and dual-AGN fractions both have a negative dependence on nuclear separation and are similar in value at small physical scales. This dependence may become stronger when restricted to high AGN luminosities, although a larger sample is needed for confirmation. These results indicate that the probability of AGN triggering increases at later merger stages. This study is the first to systematically probe down to nuclear separations of <1 kpc (∼0.8 kpc) and is consistent with predictions from simulations that AGN observability peaks in this regime. We also find that the offset AGNs are not preferentially obscured compared to the parent AGN sample, suggesting that our selection may be targeting galaxy mergers with relatively dust-free nuclear regions.

  6. Constraining the contribution of active galactic nuclei to reionization

    Science.gov (United States)

    Hassan, Sultan; Davé, Romeel; Mitra, Sourav; Finlator, Kristian; Ciardi, Benedetta; Santos, Mario G.

    2018-01-01

    Recent results have suggested that active galactic nuclei (AGN) could provide enough photons to reionize the Universe. We assess the viability of this scenario using a semi-numerical framework for modelling reionization, to which we add a quasar contribution by constructing a Quasar Halo Occupancy Distribution (QHOD) based on Giallongo et al. observations. Assuming a constant QHOD, we find that an AGN-only model cannot simultaneously match observations of the optical depth τe, neutral fraction and ionizing emissivity. Such a model predicts τe too low by ∼2σ relative to Planck constraints, and reionizes the Universe at z ≲ 5. Arbitrarily increasing the AGN emissivity to match these results yields a strong mismatch with the observed ionizing emissivity at z ∼ 5. If we instead assume a redshift-independent AGN luminosity function yielding an emissivity evolution like that assumed in Madau & Haardt model, then we can match τe albeit with late reionization; however, such evolution is inconsistent with observations at z ∼ 4-6 and poorly motivated physically. These results arise because AGN are more biased towards massive haloes than typical reionizing galaxies, resulting in stronger clustering and later formation times. AGN-dominated models produce larger ionizing bubbles that are reflected in ∼×2 more 21 cm power on all scales. A model with equal part galaxies and AGN contribution is still (barely) consistent with observations, but could be distinguished using next-generation 21 cm experiments such as Hydrogen Epoch of Reionization Array and SKA-low. We conclude that, even with recent claims of more faint AGN than previously thought, AGN are highly unlikely to dominate the ionizing photon budget for reionization.

  7. Formation of Offset and Dual Active Galactic Nuclei

    Science.gov (United States)

    Barrows, Scott; Comerford, Julia M.; Greene, Jenny E.

    2018-06-01

    Galaxy mergers are effective mechanisms for triggering accretion onto supermassive black holes (SMBHs) and thereby powering active galactic nuclei (AGN). In the merger scenario, when the SMBH from only one galaxy is accreting we observe a spatially offset AGN, and when the SMBHs from both galaxies are accreting we observe a dual AGN. Understanding the merger conditions that lead to the formation of offset AGN versus dual AGN is fundamental to informing models of hierarchical SMBH growth and the physics leading to the accretion of matter onto SMBHs. However, while the role of galaxy mergers for AGN triggering has been well-studied, the efficiency with which these events trigger offset AGN versus dual AGN is currently unclear. One reason for this gap in knowledge can be attributed to the observational difficulties in distinguishing between offset and dual AGN since doing so requires high spatial resolution, especially in the small separation regime where merger-driven AGN triggering is most likely to occur. To overcome this hurdle, we have utilized the spatial resolution of the Chandra X-ray Observatory to develop a unique sample of AGN hosted by late-stage galaxy mergers. Moreover, we have recently acquired Hubble Space Telescope imaging for a subset of these systems to examine the role that their merger morphologies play in SMBH growth and the formation of offset and dual AGN. We find that offset AGN are predominately found in minor mergers, whereas dual AGN are usually hosted by major mergers and galaxies with large morphological asymmetries. Furthermore, in both offset and dual AGN, the rate of SMBH growth increases toward more major mergers and larger morphological asymmetries. These results are in agreement with numerical simulations predicting that merger morphology is a relevant parameter governing SMBH merger-driven growth, and these results are the first to observationally confirm these trends at small pair separations.

  8. Spatially Offset Active Galactic Nuclei. II. Triggering in Galaxy Mergers

    Science.gov (United States)

    Barrows, R. Scott; Comerford, Julia M.; Greene, Jenny E.; Pooley, David

    2017-04-01

    Galaxy mergers are likely to play a role in triggering active galactic nuclei (AGNs), but the conditions under which this process occurs are poorly understood. In Paper I, we constructed a sample of spatially offset X-ray AGNs that represent galaxy mergers hosting a single AGN. In this paper, we use our offset AGN sample to constrain the parameters that affect AGN observability in galaxy mergers. We also construct dual-AGN samples with similar selection properties for comparison. We find that the offset AGN fraction shows no evidence for a dependence on AGN luminosity, while the dual-AGN fractions show stronger evidence for a positive dependence, suggesting that the merger events forming dual AGNs are more efficient at instigating accretion onto supermassive black holes than those forming offset AGNs. We also find that the offset and dual-AGN fractions both have a negative dependence on nuclear separation and are similar in value at small physical scales. This dependence may become stronger when restricted to high AGN luminosities, although a larger sample is needed for confirmation. These results indicate that the probability of AGN triggering increases at later merger stages. This study is the first to systematically probe down to nuclear separations of <1 kpc (˜0.8 kpc) and is consistent with predictions from simulations that AGN observability peaks in this regime. We also find that the offset AGNs are not preferentially obscured compared to the parent AGN sample, suggesting that our selection may be targeting galaxy mergers with relatively dust-free nuclear regions.

  9. Spectropolarimetry, variability, and the taxonomy of active galactic nuclei

    International Nuclear Information System (INIS)

    Goodrich, R.W.

    1988-01-01

    Two subclasses of active galactic nuclei (AGN) are studied using spectropolarimetry, with the intent of defining the relationships of the subclasses to other classes of AGNs, and to study the physics of the objects themselves. In the Seyfert 1.8/1.9 class there is good evidence for dust just outside of the broad-line regions in two objects, IRAS 1958-183 and NGC 2622. Spectropolarimetry of the latter object reveals the presence of dust moving at ∼ -800 s -1 along the our line-of-sight, and causing much of the polarization in the object. In addition, three of these objects have undergone extreme variability. Combining IDS data from Osterbrock and collaborators with the more recent CCD data it is shown that in all three cases the changes in both broad emission line fluxes and featureless continuum are consistent with changes in the line-of-sight reddening to the broad-line region. Together with the polarimetric evidence for dust and IRAS photometry this strongly suggests that the Seyfert 1.8/1.9 character is caused by dust and the consequent reddening and extinction. Variability occurs when dust clouds evaporate or move out of line-of-sight, and the extinction then changes. In the so-called narrow line Seyfert 1s spectropolarimetry reveals seven highly-polarized objects. In Mrk 1239 there is evidence for at least two components of polarization, one probably due to dust reflection. In two other objects, Mrk 766 and IRAS 1509-211, the polarization also appears to indicate dust reflection as the polarigenic mechanism. There is a weak circumstantial evidence for an association of the low-density region and the polarizing source, provided by comparison of the radio axes and polarization position angles in Mrk 766 and Mrk 1126

  10. TGF-β1 stimulates migration of type II endometrial cancer cells by down-regulating PTEN via activation of SMAD and ERK1/2 signaling pathways.

    Science.gov (United States)

    Xiong, Siyuan; Cheng, Jung-Chien; Klausen, Christian; Zhao, Jianfang; Leung, Peter C K

    2016-09-20

    PTEN acts as a tumor suppressor primarily by antagonizing the PI3K/AKT signaling pathway. PTEN is frequently mutated in human cancers; however, in type II endometrial cancers its mutation rate is very low. Overexpression of TGF-β1 and its receptors has been reported to correlate with metastasis of human cancers and reduced survival rates. Although TGF-β1 has been shown to regulate PTEN expression through various mechanisms, it is not yet known if the same is true in type II endometrial cancer. In the present study, we show that treatment with TGF-β1 stimulates the migration of two type II endometrial cancer cell lines, KLE and HEC-50. In addition, TGF-β1 treatment down-regulates both mRNA and protein levels of PTEN. Overexpression of PTEN or inhibition of PI3K abolishes TGF-β1-stimulated cell migration. TGF-β1 induces SMAD2/3 phosphorylation and knockdown of common SMAD4 inhibits the suppressive effects of TGF-β1 on PTEN mRNA and protein. Interestingly, TGF-β1 induces ERK1/2 phosphorylation and pre-treatment with a MEK inhibitor attenuates the suppression of PTEN protein, but not mRNA, by TGF-β1. This study provides important insights into the molecular mechanisms mediating TGF-β1-induced down-regulation of PTEN and demonstrates an important role of PTEN in the regulation of type II endometrial cancer cell migration.

  11. Insulin-induced activation of glycerol-3-phosphate acyltransferase by a chiro-inositol-containing insulin mediator is defective in adipocytes of insulin-resistant, type II diabetic, Goto-Kakizaki rats.

    OpenAIRE

    Farese, R V; Standaert, M L; Yamada, K; Huang, L C; Zhang, C; Cooper, D R; Wang, Z; Yang, Y; Suzuki, S; Toyota, T

    1994-01-01

    Type II diabetic Goto-Kakizaki (GK) rats were insulin-resistant in euglycemic-hyperinsulinemic clamp studies. We therefore examined insulin signaling systems in control Wistar and diabetic GK rats. Glycerol-3-phosphate acyltransferase (G3PAT), which is activated by headgroup mediators released from glycosyl-phosphatidylinositol (GPI), was activated by insulin in intact and cell-free adipocyte preparations of control, but not diabetic, rats. A specific chiro-inositol-containing inositol phosph...

  12. Study and modeling of the most energetic Active Galactic Nuclei with the Fermi satellite

    International Nuclear Information System (INIS)

    Sanchez, D.

    2010-06-01

    The Fermi satellite was launched in June 2008. The onboard LAT detector is dedicated to the study of galactic and extra-galactic gamma sources with an energy comprised between 200 MeV and 300 GeV. 1451 sources have been detected in less than 11 months. This document is divided into 6 chapters: 1) gamma astronomy, 2) the Fermi satellite, 3) the active galactic nuclei (NAG), 4) the observation of several blazars (PKS-2155-304 and PG-1553+113) and its simulation, 5) the observation of PKS-2155-304 with both RXTE and Fermi, and 6) conclusion

  13. The angular clustering of WISE-selected active galactic nuclei: Different halos for obscured and unobscured active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, E. [Instituto de Ciencias Astronómicas, de la Tierra, y del Espacio (ICATE), 5400 San Juan (Argentina); Yan, Lin [Infrared Processing and Analysis Center, Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Stern, D.; Assef, R. J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2014-07-01

    We calculate the angular correlation function for a sample of ∼170,000 active galactic nuclei (AGNs) extracted from the Wide-field Infrared Survey Explorer (WISE) catalog, selected to have red mid-IR colors (W1 – W2 > 0.8) and 4.6 μm flux densities brighter than 0.14 mJy). The sample is expected to be >90% reliable at identifying AGNs and to have a mean redshift of (z) = 1.1. In total, the angular clustering of WISE AGNs is roughly similar to that of optical AGNs. We cross-match these objects with the photometric Sloan Digital Sky Survey catalog and distinguish obscured sources with r – W2 > 6 from bluer, unobscured AGNs. Obscured sources present a higher clustering signal than unobscured sources. Since the host galaxy morphologies of obscured AGNs are not typical red sequence elliptical galaxies and show disks in many cases, it is unlikely that the increased clustering strength of the obscured population is driven by a host galaxy segregation bias. By using relatively complete redshift distributions from the COSMOS survey, we find that obscured sources at (z) ∼ 0.9 have a bias of b = 2.9 ± 0.6 and are hosted in dark matter halos with a typical mass of log (M/M {sub ☉} h {sup –1}) ∼ 13.5. In contrast, unobscured AGNs at (z) ∼ 1.1 have a bias of b = 1.6 ± 0.6 and inhabit halos of log (M/M {sub ☉} h {sup –1}) ∼ 12.4. These findings suggest that obscured AGNs inhabit denser environments than unobscured AGNs, and they are difficult to reconcile with the simplest AGN unification models, where obscuration is driven solely by orientation.

  14. PAH features within few hundred parsecs of active galactic nuclei

    Science.gov (United States)

    Jensen, J. J.; Hönig, S. F.; Rakshit, S.; Alonso-Herrero, A.; Asmus, D.; Gandhi, P.; Kishimoto, M.; Smette, A.; Tristram, K. R. W.

    2017-09-01

    Spectral features from polycyclic aromatic hydrocarbon (PAH) molecules observed in the mid-infrared (mid-IR) range are typically used to infer the amount of recent and ongoing star formation on kiloparsec scales around active galactic nuclei (AGN) where more traditional methods fail. This method assumes that the observed PAH features are excited predominantly by star formation. With current ground-based telescopes and the upcoming James Webb Space Telescope, much smaller spatial scales can be probed and we aim at testing if this assumption still holds in the range of few tens to few hundreds of parsecs. For that, we spatially map the emitted 11.3 μm PAH surface flux as a function of distance from 0.4-4 arcsec from the centre in 28 nearby AGN using ground-based high-angular-resolution mid-IR spectroscopy. We detect and extract the 11.3 μm PAH feature in 13 AGN. The fluxes within each aperture are scaled to a luminosity-normalized distance from the nucleus to be able to compare intrinsic spatial scales of AGN radiation spanning about two orders of magnitude in luminosity. For this, we establish an empirical relation between the absorption-corrected X-ray luminosity and the sublimation radius in these sources. Once normalized, the radial profiles of the emitted PAH surface flux show similar radial slopes, with a power-law index of approximately -1.1, and similar absolute values, consistent within a factor of a few of each other as expected from the uncertainty in the intrinsic scale estimate. We interpret this as evidence that the profiles are caused by a common compact central physical process, either the AGN itself or circumnuclear star formation linked in strength to the AGN power. A photoionization-based model of an AGN exciting dense clouds in its environment can reproduce the observed radial slope and confirms that the AGN radiation field is strong enough to explain the observed PAH surface fluxes within ∼10-500 pc of the nucleus. Our results advice caution

  15. Active galactic nuclei. From the central engine to the host galaxy

    International Nuclear Information System (INIS)

    Gilbert, Didier

    2008-01-01

    After some recalls on galaxies, on their classification, on the Universe expansion and on the Hubble law, this academic report addresses active galactic nuclei (AGN) by describing their anatomy (central black hole, accretion disk, jets and winds, Broad Line Region, Narrow Line Region, molecular torus and dusts, radio lobes). The author also presents the unified model. In the next part, he proposes an overview of active galaxies and active galactic nuclei by distinguishing galaxies with a strong stellar activity, radio-quiet and radio-loud active galactic nuclei. Examples are presented for each of these types. In the last part, the author draws perspectives for research in cosmology, and outlines questions which are still to be answered

  16. Outflow and Accretion Physics in Active Galactic Nuclei

    Science.gov (United States)

    McGraw, Sean Michael

    2016-09-01

    This dissertation focuses on placing observational constraints on outflows and accretion disks in active galactic nuclei (AGN) for the purpose of better understanding the physics of super-massive black holes (SMBHs) and their evolution with the host galaxy over cosmic time. Quasar outflows and their importance in SMBH-host galaxy co-evolution can be further understood by analyzing broad absorption lines (BALs) in rest-frame UV spectra that trace a range of wind conditions. We quantify the properties of the flows by conducting BAL variability studies using multiple-epoch spectra acquired primarily from MDM Observatory and from the Sloan Digital Sky Survey. Iron low-ionization BALs (FeLoBALs) are a rare type of outflow that may represent a transient phase in galaxy evolution, and we analyze the variations in 12 FeLoBAL quasars with redshifts between 0.7 ≤ z ≤ 1.9 and rest frame timescales between ˜10 d to 7.6 yr. We investigate BAL variability in 71 quasar outflows that exhibit P V absorption, a tracer of high column density gas (i.e. NH ≥ 1022 cm -2), in order to quantify the energies and momenta of the flows. We also characterize the variability patterns of 26 quasars with mini-BALs, an interesting class of absorbers that may represent a distinct phase in the evolution of outflows. Low-luminosity AGN (LLAGN) are important objects to study since their prominence in the local Universe suggest a possible evolution from the quasar era, and their low radiative outputs likely indicate a distinct mode of accretion onto the SMBH. We probe the accretion conditions in the LLAGN NGC 4203 by estimating the SMBH mass, which is obtained by modeling the 2-dimensional velocity field of the nebular gas using spectra from the Hubble Space Telescope. We detect significant BAL and mini-BAL variability in a subset of quasars from each of our samples, with measured rest-frame variability time-scales from days to years and over multiple years on average. Variable wavelength

  17. Reverberation Mapping of the Continuum Source in Active Galactic Nuclei

    Science.gov (United States)

    Fausnaugh, Michael Martin

    I present results from a monitoring campaign of 11 active galactic nuclei (AGN) conducted in Spring of 2014. I use the reverberation mapping method to probe the interior structures of the AGN, specifically the broad line regions (BLRs) and accretion disks. One of these AGN, NGC 5548, was also subject to multi-wavelength (X-ray, UV, optical, and near-IR) monitoring using 25 ground-based telescopes and four space-based facilities. For NGC 5548, I detect lags between the continuum emission at different wavelengths that follow a trend consistent with the prediction for continuum reprocessing by an accretion disk with temperature profile T ∝ R -3/4. However, the lags imply a disk radius that is 3 times larger than the prediction from standard thin-disk models. The lags at wavelengths longer than the Vband are also equal to or greater than the lags of high-ionization-state emission lines (such as HeII lambda1640 and lambda4686), suggesting that the continuum-emitting source is of a physical size comparable to the inner broad-line region. Using optical spectra from the Large Binocular Telescope, I estimate the bias of the interband continuum lags due to BLR emission observed in the filters, and I find that the bias for filters with high levels of BLR contamination (˜20%) can be important for the shortest continuum lags. This likely has a significant impact on the u and U bands owing to Balmer continuum emission. I then develop a new procedure for the internal (night-to-night) calibration of time series spectra that can reach precisions of ˜1 millimagnitude and improves traditional techniques by up to a factor of 5. At this level, other systematic issues (e.g., the nightly sensitivity functions and Fe II contamination) limit the final precision of the observed light curves. Using the new calibration method, I next present the data and first results from the optical spectroscopic monitoring component of the reverberation mapping campaign. Five AGN were sufficiently

  18. Active Galactic Nuclei: Sources for ultra high energy cosmic rays?

    International Nuclear Information System (INIS)

    Biermann, Peter L.; Becker, Julia K.; Caramete, Laurentiu; Curutiu, Alex; Engel, Ralph; Falcke, Heino; Gergely, Laszlo A.; Isar, P. Gina; Maris, Ioana C.; Meli, Athina; Kampert, Karl-Heinz; Stanev, Todor; Tascau, Oana; Zier, Christian

    2009-01-01

    The origin of ultra high energy cosmic rays promises to lead us to a deeper understanding of the structure of matter. This is possible through the study of particle collisions at center-of-mass energies in interactions far larger than anything possible with the Large Hadron Collider, albeit at the substantial cost of no control over the sources and interaction sites. For the extreme energies we have to identify and understand the sources first, before trying to use them as physics laboratories. Here we describe the current stage of this exploration. The most promising contenders as sources are radio galaxies and gamma ray bursts. The sky distribution of observed events yields a hint favoring radio galaxies. Key in this quest are the intergalactic and galactic magnetic fields, whose strength and structure are not yet fully understood. Current data and statistics do not yet allow a final judgement. We outline how we may progress in the near future.

  19. Active Galactic Nuclei: Sources for ultra high energy cosmic rays?

    Energy Technology Data Exchange (ETDEWEB)

    Biermann, Peter L. [MPI for Radioastronomy, Bonn (Germany); Dept. of Phys. and Astron., Univ. of Bonn (Germany); Dept. of Phys. and Astr., Univ. of Alabama, Tuscaloosa, AL (United States); Dept. of Phys., Univ. of Alabama at Huntsville, AL (United States); Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Becker, Julia K. [Institution foer Fysik, Goeteborgs Univ. (Sweden); Dept. of Phys., Univ. Dortmund, Dortmund (Germany); Caramete, Laurentiu [MPI for Radioastronomy, Bonn (Germany); Institute for Space Studies, Bucharest (Romania); Curutiu, Alex [MPI for Radioastronomy, Bonn (Germany); Engel, Ralph [Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Falcke, Heino [Dept. of Astrophys., IMAP, Radboud Univ., Nijmegen (Netherlands); ASTRON, Dwingeloo (Netherlands); Gergely, Laszlo A. [Dept. Appl. Sci., London South Bank University (United Kingdom); Dept. of Theoret. and Exp. Phys., Univ. of Szeged, Szeged (Hungary); Isar, P. Gina [Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Institute for Space Studies, Bucharest (Romania); Maris, Ioana C. [Inst. Nucl. Phys. FZ, Karlsruhe Inst. of Techn. (KIT) (Germany); Meli, Athina [Physik. Inst. Univ. Erlangen-Nuernberg (Germany); Kampert, Karl-Heinz [Phys. Dept., Univ. Wuppertal (Germany); Stanev, Todor [Bartol Research Inst., Univ. of Delaware, Newark, DE (United States); Tascau, Oana [Phys. Dept., Univ. Wuppertal (Germany); Zier, Christian [MPI for Radioastronomy, Bonn (Germany); Raman Res. Inst., Bangalore (India)

    2009-05-15

    The origin of ultra high energy cosmic rays promises to lead us to a deeper understanding of the structure of matter. This is possible through the study of particle collisions at center-of-mass energies in interactions far larger than anything possible with the Large Hadron Collider, albeit at the substantial cost of no control over the sources and interaction sites. For the extreme energies we have to identify and understand the sources first, before trying to use them as physics laboratories. Here we describe the current stage of this exploration. The most promising contenders as sources are radio galaxies and gamma ray bursts. The sky distribution of observed events yields a hint favoring radio galaxies. Key in this quest are the intergalactic and galactic magnetic fields, whose strength and structure are not yet fully understood. Current data and statistics do not yet allow a final judgement. We outline how we may progress in the near future.

  20. The COS-AGN survey: Revealing the nature of circum-galactic gas around hosts of active galactic nuclei

    Science.gov (United States)

    Berg, Trystyn A. M.; Ellison, Sara L.; Tumlinson, Jason; Oppenheimer, Benjamin D.; Horton, Ryan; Bordoloi, Rongmon; Schaye, Joop

    2018-04-01

    Active galactic nuclei (AGN) are thought to play a critical role in shaping galaxies, but their effect on the circumgalactic medium (CGM) is not well studied. We present results from the COS-AGN survey: 19 quasar sightlines that probe the CGM of 20 optically-selected AGN host galaxies with impact parameters 80 frame equivalent widths EW≥124 mÅ) whilst many of the metal ions are not detected in individual sightlines. A sightline-by-sightline comparison between COS-AGN and the control sample yields no significant difference in EW distribution. However, stacked spectra of the COS-AGN and control samples show significant (>3σ) enhancements in the EW of both Siiii And Lyα at impact parameters >164 kpc by a factor of +0.45 ± 0.05 dex and >+0.75 dex respectively. The lack of detections of both high-ionization species near the AGN and strong kinematic offsets between the absorption systemic galaxy redshifts indicates that neither the AGN's ionization nor its outflows are the origin of these differences. Instead, we suggest the observed differences could result from either AGN hosts residing in haloes with intrinsically distinct gas properties, or that their CGM has been affected by a previous event, such as a starburst, which may also have fuelled the nuclear activity.

  1. Active galactic nuclei and their role in galaxy evolution : The infrared perspective

    NARCIS (Netherlands)

    Caputi, K. I.

    The remarkable progress made in infrared (IR) astronomical instruments over the last 10-15 years has radically changed our vision of the extragalactic IR sky, and overall understanding of galaxy evolution. In particular, this has been the case for the study of active galactic nuclei (AGN), for which

  2. Simulating Galaxies and Active Galactic Nuclei in the LSST Image Simulation Effort

    NARCIS (Netherlands)

    Pizagno II, Jim; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Chang, C.; Gibson, R. R.; Gilmore, K.; Grace, E.; Hannel, M.; Jernigan, J. G.; Jones, L.; Kahn, S. M.; Krughoff, S. K.; Lorenz, S.; Marshall, S.; Shmakova, S. M.; Sylvestri, N.; Todd, N.; Young, M.

    We present an extragalactic source catalog, which includes galaxies and Active Galactic Nuclei, that is used for the Large Survey Synoptic Telescope Imaging Simulation effort. The galaxies are taken from the De Lucia et. al. (2006) semi-analytic modeling (SAM) of the Millennium Simulation. The LSST

  3. Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

    NARCIS (Netherlands)

    Abraham, J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Anzalone, A.; Aramo, C.; Argiro, S.; Arisaka, K.; Armengaud, E.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Atulugama, B. S.; Aublin, J.; Ave, M.; Avila, G.; Baecker, T.; Badagnani, D.; Barbosa, A. F.; Barnhill, D.; Barroso, S. L. C.; Bauleo, P.; Beatty, J. J.; Beau, T.; Becker, B. R.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bergmann, T.; Bernardini, P.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Blasi, P.; Bleve, C.; Bluemer, H.; Bohacova, M.; Bonifazi, C.; Bonino, R.; Brack, J.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Burton, R. E.; Busca, N. G.; Caballero-Mora, K. S.; Cai, B.; Camin, D. V.; Caramete, L.; Caruso, R.; Carvalho, W.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chye, J.; Clay, R. W.; Colombo, E.; Conceicao, R.; Connolly, B.; Contreras, F.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Donato, C.; Bg, S. J. de Jong; De La Vega, G.; de Mello, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; Di Giulio, C.; Diaz, J. C.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dornic, D.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; DuVernois, M. A.; Engel, R.; Epele, L.; Escobar, C. O.; Etchegoyen, A.; Luis, P. Facal San; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferrer, F.; Ferry, S.; Fick, B.; Filevich, A.; Filipcic, A.; Fleck, I.; Fracchiolla, C. E.; Fulgione, W.; Garcia, B.; Gaimez, D. Garcia; Garcia-Pinto, D.; Garrido, X.; Geenen, H.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Albarracin, F. Gomez; Berisso, M. Gomez; Herrero, R. Gomez; Goncalves, P.; do Amaral, M. Goncalves; Gonzalez, D.; Gonzalezc, J. G.; Gonzalez, M.; Gora, D.; Gorgi, A.; Gouffon, P.; Grassi, V.; Grillo, A. F.; Grunfeld, C.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Gutierrez, J.; Hague, J. D.; Hamilton, J. C.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hauschildt, T.; Healy, M. D.; Hebbeker, T.; Hebrero, G.; Heck, D.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hoerandel, J.; Horneffer, A.; Horvat, M.; Hrabovsky, M.; Huege, T.; Hussain, M.; Larlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Kaducak, M.; Kampert, K. H.; Karova, T.; Kegl, B.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koanga, V. -H.; Krieger, A.; Kroemer, O.; Kuempel, D.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Lebrun, D.; LeBrun, P.; Lee, J.; de Oliveira, M. A. Leigui; Lopez, R.; Letessier-Selvon, A.; Leuthold, M.; Lhenry-Yvon, I.; Aguera, A. Lopez; Bahilo, J. Lozano; Garcia, R. Luna; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mancarella, G.; Mancenido, M. E.; Mandatat, D.; Mantsch, P.; Mariazzi, A. G.; Maris, I. C.; Falcon, H. R. Marquez; Martello, D.; Martinez, J.; Bravo, O. Martinez; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McCauley, T.; McEwen, M.; McNeil, R. R.; Medina, M. C.; Medina-Tanco, G.; Meli, A.; Melo, D.; Menichetti, E.; Menschikov, A.; Meurer, Chr.; Meyhandan, R.; Micheletti, M. I.; Miele, G.; Miller, W.; Mollerach, S.; Monasor, M.; Ragaigne, D. Monnier; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Morris, C.; Mostafa, M.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Newman-Holmes, C.; Newton, D.; Nhung, P. T.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nozka, L.; Oehlschlaeger, J.; Ohnuki, T.; Olinto, A.; Olmos-Gilbaja, V. M.; Ortiz, M.; Ortolani, F.; Ostapchenko, S.; Otero, L.; Pacheco, N.; Selmi-Dei, D. Pakk; Palatka, M.; Pallotta, J.; Parente, G.; Parizot, E.; Parlati, S.; Pastor, S.; Patel, M.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petrera, S.; Petrinca, P.; Petrov, Y.; Pichel, A.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pinto, T.; Pirronello, V.; Pisanti, O.; Platino, M.; Pochon, J.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Redondo, A.; Reucroft, S.; Revenu, B.; Rezende, F. A. S.; Ridky, J.; Riggi, S.; Risse, M.; Riviere, C.; Rizi, V.; Roberts, M.; Robledo, C.; Rodriguez, G.; Martino, J. Rodriguez; Rojo, J. Rodriguez; Rodriguez-Cabo, I.; Rodriguez-Frias, M. D.; Ros, G.; Rosado, J.; Roth, M.; Rouille-d'Orfeuil, B.; Roulet, E.; Roverok, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sanchez, F.; Santander, M.; Santo, C. E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scherini, V.; Schieler, H.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schovanek, P.; Schuessler, F.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Semikoz, D.; Settimo, M.; Shellard, R. C.; Sidelnik, I.; Siffert, B. B.; Sigl, G.; De Grande, N. Smetniansky; Smialkowski, A.; Smida, R.; Smith, A. G. K.; Smith, B. E.; Snow, G. R.; Sokolsky, P.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijarvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Takahashi, J.; Tamashiro, A.; Tamburro, A.; Tascau, O.; Tcaciuc, R.; Thao, N. T.; Thomas, D.; Ticona, R.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Peixoto, C. J. Todero; Tome, B.; Tonachini, A.; Torres, I.; Travnicek, P.; Tripathi, A.; Tristram, G.; Tscherniakhovski, D.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Galicia, J. F. Valdes; Valino, I.; Valore, L.; van den Berg, A. M.; van Elewyck, V.; Vazquez, R. A.; Veberic, D.; Veiga, A.; Velarde, A.; Venters, T.; Verzi, V.; Videla, M.; Villasenor, L.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wainberg, O.; Warner, D.; Watson, A. A.; Westerhoff, S.; Wieczorek, G.; Wiencke, L.; Wilczynska, B.; Wilczynski, H.; Wileman, C.; Winnick, M. G.; Wu, H.; Wundheiler, B.; Yamamoto, T.; Younk, P.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zech, A.; Zepeda, A.; Ziolkowski, M.

    Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest-energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [Pierre Auger Collaboration, Science 318 (2007) 938]. The

  4. EVN observations of low-luminosity flat-spectrum active galactic nuclei

    NARCIS (Netherlands)

    Caccianiga, A; Marcha, MJM; Thean, A; Dennett-Thorpe, J

    2001-01-01

    We present and discuss the results of very-long baseline interferometry (VLBI, EVN) observations of three low-luminosity (P-5GHz <10(25) W Hz(-1)) broad emission line active galactic nuclei (AGNs) carefully selected from a sample of flat-spectrum radio sources (CLASS). Based on the total and the

  5. Obscured flat spectrum radio active galactic nuclei as sources of high-energy neutrinos

    NARCIS (Netherlands)

    Maggi, G.; Buitink, S.; Correa, P.; de Vries, K. D.; Gentile, G.; Tavares, J. León; Scholten, O.; van Eijndhoven, N.; Vereecken, M.; Winchen, T.

    2016-01-01

    Active galactic nuclei (AGN) are believed to be one of the main source candidates for the high-energy (TeV-PeV) cosmic neutrino flux recently discovered by the IceCube neutrino observatory. Nevertheless, several correlation studies between AGN and the cosmic neutrinos detected by IceCube show no

  6. General relativistic model for the gravitational field of active galactic nuclei surrounded by a disk

    NARCIS (Netherlands)

    Vogt, D.; Letelier, P.S.

    2005-01-01

    An exact but simple general relativistic model for the gravitational field of active galactic nuclei is constructed, based on the superposition in Weyl coordinates of a black hole, a Chazy-Curzon disk and two rods, which represent matter jets. The influence of the rods on the matter properties of

  7. Alveolar epithelial type II cells induce T cell tolerance to specific antigen

    DEFF Research Database (Denmark)

    Lo, Bernice; Hansen, Søren; Evans, Kathy

    2008-01-01

    The lungs face the immunologic challenge of rapidly eliminating inhaled pathogens while maintaining tolerance to innocuous Ags. A break in this immune homeostasis may result in pulmonary inflammatory diseases, such as allergies or asthma. The observation that alveolar epithelial type II cells (Type...... II) constitutively express the class II MHC led us to hypothesize that Type II cells play a role in the adaptive immune response. Because Type II cells do not express detectable levels of the costimulatory molecules CD80 and CD86, we propose that Type II cells suppress activation of naive T cells...

  8. Towards a physical model of dust tori in Active Galactic Nuclei. Radiative transfer calculations for a hydrostatic torus model

    Science.gov (United States)

    Schartmann, M.; Meisenheimer, K.; Camenzind, M.; Wolf, S.; Henning, Th.

    2005-07-01

    We explore physically self-consistent models of dusty molecular tori in Active Galactic Nuclei (AGN) with the goal of interpreting VLTI observations and fitting high resolution mid-IR spectral energy distributions (SEDs). The input dust distribution is analytically calculated by assuming hydrostatic equilibrium between pressure forces - due to the turbulent motion of the gas clouds - and gravitational and centrifugal forces as a result of the contribution of the nuclear stellar distribution and the central black hole. For a fully three-dimensional treatment of the radiative transfer problem through the tori we employ the Monte Carlo code MC3D. We find that in homogeneous dust distributions the observed mid-infrared emission is dominated by the inner funnel of the torus, even when observing along the equatorial plane. Therefore, the stratification of the distribution of dust grains - both in terms of size and composition - cannot be neglected. In the current study we only include the effect of different sublimation radii which significantly alters the SED in comparison to models that assume an average dust grain property with a common sublimation radius, and suppresses the silicate emission feature at 9.7~μm. In this way we are able to fit the mean SED of both type I and type II AGN very well. Our fit of special objects for which high angular resolution observations (≤0.3´´) are available indicates that the hottest dust in NGC 1068 reaches the sublimation temperature while the maximum dust temperature in the low-luminosity AGN Circinus falls short of 1000 K.

  9. Supermassive Black Holes in Active Galactic Nuclei. II. Calibration of the Black Hole Mass-Velocity Dispersion Relationship for Active Galactic Nuclei

    DEFF Research Database (Denmark)

    Onken, Christopher A.; Ferrarese, Laura; Merritt, David

    2004-01-01

    We calibrate reverberation-based black hole masses in active galactic nuclei (AGNs) by using the correlation between black hole mass, M, and bulge/spheroid stellar velocity dispersion, sigma. We use new measurements of sigma for 6 AGNs and published velocity dispersions for 10 others......, in conjunction with improved reverberation mapping results, to determine the scaling factor required to bring reverberation-based black hole masses into agreement with the quiescent galaxy M-sigma relationship. The scatter in the AGN black hole masses is found to be less than a factor of 3. The current...

  10. MAJOR GALAXY MERGERS ONLY TRIGGER THE MOST LUMINOUS ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Treister, E.; Schawinski, K.; Urry, C. M.; Simmons, B. D.

    2012-01-01

    Using multiwavelength surveys of active galactic nuclei (AGNs) across a wide range of bolometric luminosities (10 43 bol (erg s –1 ) 46 ) and redshifts (0 bol -f merger relation suggests that downsizing, i.e., the general decline in AGN and star formation activity with decreasing redshift, is driven by a decline in the frequency of major mergers combined with a decrease in the availability of gas at lower redshifts.

  11. Glutathione synthesis and homeostasis in isolated type II alveolar cells

    International Nuclear Information System (INIS)

    Saito, K.; Warshaw, J.B.; Prough, R.A.

    1986-01-01

    After isolation of Type II cells from neonatal rat lung, the glutathione (GSH) levels in these cells were greatly depressed. The total glutathione content could be increased 5-fold within 12-24 h by incubating the cells in media containing sulfur amino acids. Similarly, the activity of γ-glutamyltranspeptidase was low immediately after isolation, but was increased 2-fold during the first 24 h culture. Addition of either GSH or GSSG to the culture media increased the GSH content of Type II cells 2-2.5-fold. Buthionine sulfoximine and NaF prevented this replenishment of GSH during 24 h culture. When the rates of de novo synthesis of GSH and GSSG from 35 S-cysteine were measured, the amounts of newly formed GSH decreased to 80% in the presence of GSH or GSSG. This suggests that exogenous GSH/GSSG can be taken up by the Type II cells to replenish the intracellular pool of GSH. Methionine was not as effective as cysteine in the synthesis of GSH. These results suggest that GSH levels in the isolated Type II cell can be maintained by de novo synthesis or uptake of exogenous GSH. Most of the GSH synthesized from cysteine, however, was excreted into the media of the cultured cells indicative of a potential role for the type II cell in export of the non-protein thiol

  12. A MID-INFRARED CENSUS OF STAR FORMATION ACTIVITY IN BOLOCAM GALACTIC PLANE SURVEY SOURCES

    International Nuclear Information System (INIS)

    Dunham, Miranda K.; Robitaille, Thomas P.; Evans, Neal J. II; Schlingman, Wayne M.; Cyganowski, Claudia J.; Urquhart, James

    2011-01-01

    We present the results of a search for mid-infrared signs of star formation activity in the 1.1 mm sources in the Bolocam Galactic Plane Survey (BGPS). We have correlated the BGPS catalog with available mid-IR Galactic plane catalogs based on the Spitzer Space Telescope GLIMPSE legacy survey and the Midcourse Space Experiment (MSX) Galactic plane survey. We find that 44% (3712 of 8358) of the BGPS sources contain at least one mid-IR source, including 2457 of 5067 (49%) within the area where all surveys overlap (10 deg. s tarlessBGPS sources which were not matched to any mid-IR sources. The mean 1.1 mm flux of each group increases with increasing probability of active star formation. We also find that the 'starless' BGPS sources are the most compact, while the sources with the highest probability of star formation activity are on average more extended with large skirts of emission. A subsample of 280 BGPS sources with known distances demonstrates that mass and mean H 2 column density also increase with probability of star formation activity.

  13. Searching for axion-like particles with active-galactic nuclei

    International Nuclear Information System (INIS)

    Burrage, Clare; Davis, Anne-Christine; Shaw, Douglas J.

    2009-12-01

    Strong mixing between photons and axion-like particles in the magnetic fields of clusters of galaxies induces a scatter in the observed luminosities of compact sources in the cluster. This is used to construct a new test for axion-like particles; applied to observations of active galactic nuclei it is strongly suggestive of the existence of a light axion-like particle. (orig.)

  14. Searching for axion-like particles with active-galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Davis, Anne-Christine [Centre for Mathematical Sciences, Cambridge (United Kingdom). Dept. of Applied Mathematics and Theoretical Physics; Shaw, Douglas J. [Queen Mary Univ. of London (United Kingdom). Astronomy Unit, School of Mathematical Sciences

    2009-12-15

    Strong mixing between photons and axion-like particles in the magnetic fields of clusters of galaxies induces a scatter in the observed luminosities of compact sources in the cluster. This is used to construct a new test for axion-like particles; applied to observations of active galactic nuclei it is strongly suggestive of the existence of a light axion-like particle. (orig.)

  15. Spectral-luminosity evolution of active galactic nuclei (AGN)

    Science.gov (United States)

    Leiter, Darryl; Boldt, Elihu

    1992-01-01

    The origin of the cosmic X-ray and gamma-ray backgrounds is explained via the mechanism of AGN spectral-luminosity evolution. The spectral evolution of precursor active galaxies into AGN, and Newton-Raphson input and output parameters are discussed.

  16. Knowledge Is Power: Teaching Children about Type II Diabetes

    Science.gov (United States)

    Feild-Berner, Natalie; Balgopal, Meena

    2011-01-01

    World Diabetes Day (November 14) offers a wonderful opportunity to educate elementary children about the power they have to control their health. First lady Michelle Obama has urged Americans to educate themselves about childhood obesity, which is often associated with the onset of type II diabetes (Rabin 2010). The authors developed activities to…

  17. Plasma phospholipid transfer protein activity is related to insulin resistance : impaired acute lowering by insulin in obese Type II diabetic patients

    NARCIS (Netherlands)

    Riemens, SC; van Tol, A; Sluiter, WJ; Dullaart, RPF

    Cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP) have important functions in high density lipoprotein (HDL) metabolism. We determined the association of plasma CETP and PLTP activities (measured with exogenous' substrate assays) with insulin resistance, plasma

  18. Insulin-induced activation of glycerol-3-phosphate acyltransferase by a chiro-inositol-containing insulin mediator is defective in adipocytes of insulin-resistant, type II diabetic, Goto-Kakizaki rats.

    Science.gov (United States)

    Farese, R V; Standaert, M L; Yamada, K; Huang, L C; Zhang, C; Cooper, D R; Wang, Z; Yang, Y; Suzuki, S; Toyota, T

    1994-11-08

    Type II diabetic Goto-Kakizaki (GK) rats were insulin-resistant in euglycemic-hyperinsulinemic clamp studies. We therefore examined insulin signaling systems in control Wistar and diabetic GK rats. Glycerol-3-phosphate acyltransferase (G3PAT), which is activated by headgroup mediators released from glycosyl-phosphatidylinositol (GPI), was activated by insulin in intact and cell-free adipocyte preparations of control, but not diabetic, rats. A specific chiro-inositol-containing inositol phosphoglycan (IPG) mediator, prepared from beef liver, bypassed this defect and comparably activated G3PAT in cell-free adipocyte preparations of both diabetic GK and control rats. A myo-inositol-containing IPG mediator did not activate G3PAT. Relative to control adipocytes, labeling of GPI by [3H]glucosamine was diminished by 50% and insulin failed to stimulate GPI hydrolysis in GK adipocytes. In contrast to GPI-dependent G3PAT activation, insulin-stimulated hexose transport was intact in adipocytes and soleus and gastrocnemius muscles of the GK rat, as was insulin-induced activation of mitogen-activated protein kinase and protein kinase C. We conclude that (i) chiro-inositol-containing IPG mediator activates G3PAT during insulin action, (ii) diabetic GK rats have a defect in synthesizing or releasing functional chiro-inositol-containing IPG, and (iii) defective IPG-regulated intracellular glucose metabolism contributes importantly to insulin resistance in diabetic GK rats.

  19. CO LINE EMISSION FROM COMPACT NUCLEAR STARBURST DISKS AROUND ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Armour, J. N.; Ballantyne, D. R., E-mail: jarmour3@gatech.edu [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332-0430 (United States)

    2012-06-20

    There is substantial evidence for a connection between star formation in the nuclear region of a galaxy and growth of the central supermassive black hole. Furthermore, starburst activity in the region around an active galactic nucleus (AGN) may provide the obscuration required by the unified model of AGNs. Molecular line emission is one of the best observational avenues to detect and characterize dense, star-forming gas in galactic nuclei over a range of redshift. This paper presents predictions for the carbon monoxide (CO) line features from models of nuclear starburst disks around AGNs. These small-scale ({approx}< 100 pc), dense and hot starbursts have CO luminosities similar to scaled-down ultra-luminous infrared galaxies and quasar host galaxies. Nuclear starburst disks that exhibit a pc-scale starburst and could potentially act as the obscuring torus show more efficient CO excitation and higher brightness temperature ratios than those without such a compact starburst. In addition, the compact starburst models predict strong absorption when J{sub Upper} {approx}> 10, a unique observational signature of these objects. These findings allow for the possibility that CO spectral line energy distributions (SLEDs) could be used to determine if starburst disks are responsible for the obscuration in z {approx}< 1 AGNs. Directly isolating the nuclear CO line emission of such compact regions around AGNs from galactic-scale emission will require high-resolution imaging or selecting AGN host galaxies with weak galactic-scale star formation. Stacking individual CO SLEDs will also be useful in detecting the predicted high-J features.

  20. In vitro inhibitory activities of selected Australian medicinal plant extracts against protein glycation, angiotensin converting enzyme (ACE) and digestive enzymes linked to type II diabetes.

    Science.gov (United States)

    Deo, Permal; Hewawasam, Erandi; Karakoulakis, Aris; Claudie, David J; Nelson, Robert; Simpson, Bradley S; Smith, Nicholas M; Semple, Susan J

    2016-11-04

    There is a need to develop potential new therapies for the management of diabetes and hypertension. Australian medicinal plants collected from the Kuuku I'yu (Northern Kaanju) homelands, Cape York Peninsula, Queensland, Australia were investigated to determine their therapeutic potential. Extracts were tested for inhibition of protein glycation and key enzymes relevant to the management of hyperglycaemia and hypertension. The inhibitory activities were further correlated with the antioxidant activities. Extracts of five selected plant species were investigated: Petalostigma pubescens, Petalostigma banksii, Memecylon pauciflorum, Millettia pinnata and Grewia mesomischa. Enzyme inhibitory activity of the plant extracts was assessed against α-amylase, α-glucosidase and angiotensin converting enzyme (ACE). Antiglycation activity was determined using glucose-induced protein glycation models and formation of protein-bound fluorescent advanced glycation endproducts (AGEs). Antioxidant activity was determined by measuring the scavenging effect of plant extracts against 1, 1-diphenyl-2-picryl hydrazyl (DPPH) and using the ferric reducing anti-oxidant potential assay (FRAP). Total phenolic and flavonoid contents were also determined. Extracts of the leaves of Petalostigma banksii and P. pubescens showed the strongest inhibition of α-amylase with IC 50 values of 166.50 ± 5.50 μg/mL and 160.20 ± 27.92 μg/mL, respectively. The P. pubescens leaf extract was also the strongest inhibitor of α-glucosidase with an IC 50 of 167.83 ± 23.82 μg/mL. Testing for the antiglycation potential of the extracts, measured as inhibition of formation of protein-bound fluorescent AGEs, showed that P. banksii root and fruit extracts had IC 50 values of 34.49 ± 4.31 μg/mL and 47.72 ± 1.65 μg/mL, respectively, which were significantly lower (p < 0.05) than other extracts. The inhibitory effect on α-amylase, α-glucosidase and the antiglycation potential of

  1. Unification of Active Galactic Nuclei at X-rays and soft gamma-rays

    International Nuclear Information System (INIS)

    Beckmann, Volker

    2010-01-01

    This HDR (accreditation to supervise research) report contains presentations of teaching activities in stellar astrophysics and extragalactic astronomy and cosmology, of student supervision activities in different academic places, and of various publications and participations to conferences and meetings. After a brief text highlighting the relevance and originality of his research works, the author proposes a large overview of his research works which dealt with different aspects of active galactic nuclei and related issues. Future projects are evoked. The report also contains numerous publications (press articles, conference proceedings, and so on)

  2. Edaravone suppresses degradation of type II collagen.

    Science.gov (United States)

    Huang, Chen; Liao, Guangjun; Han, Jian; Zhang, Guofeng; Zou, Benguo

    2016-05-13

    Osteoarthritis (OA) is a degenerative joint disease affecting millions of people. The degradation and loss of type II collagen induced by proinflammatory cytokines secreted by chondrocytes, such as factor-α (TNF-α) is an important pathological mechanism to the progression of OA. Edaravone is a potent free radical scavenger, which has been clinically used to treat the neuronal damage following acute ischemic stroke. However, whether Edaravone has a protective effect in articular cartilage hasn't been reported before. In this study, we investigated the chondrocyte protective effects of Edaravone on TNF-α induced degradation of type Ⅱ collagen. And our results indicated that TNF-α treatment resulted in degradation of type Ⅱ collagen, which can be ameliorated by treatment with Edaravone in a dose dependent manner. Notably, it was found that the inhibitory effects of Edaravone on TNF-α-induced reduction of type Ⅱ collagen were mediated by MMP-3 and MMP-13. Mechanistically, we found that Edaravone alleviated TNF-α induced activation of STAT1 and expression of IRF-1. These findings suggest a potential protective effect of Edaravone in OA. Copyright © 2016. Published by Elsevier Inc.

  3. Current Understanding of Usher Syndrome Type II

    Science.gov (United States)

    Yang, Jun; Wang, Le; Song, Hongman; Sokolov, Maxim

    2012-01-01

    Usher syndrome is the most common deafness-blindness caused by genetic mutations. To date, three genes have been identified underlying the most prevalent form of Usher syndrome, the type II form (USH2). The proteins encoded by these genes are demonstrated to form a complex in vivo. This complex is localized mainly at the periciliary membrane complex in photoreceptors and the ankle-link of the stereocilia in hair cells. Many proteins have been found to interact with USH2 proteins in vitro, suggesting that they are potential additional components of this USH2 complex and that the genes encoding these proteins may be the candidate USH2 genes. However, further investigations are critical to establish their existence in the USH2 complex in vivo. Based on the predicted functional domains in USH2 proteins, their cellular localizations in photoreceptors and hair cells, the observed phenotypes in USH2 mutant mice, and the known knowledge about diseases similar to USH2, putative biological functions of the USH2 complex have been proposed. Finally, therapeutic approaches for this group of diseases are now being actively explored. PMID:22201796

  4. DUST IN ACTIVE GALACTIC NUCLEI: ANOMALOUS SILICATE TO OPTICAL EXTINCTION RATIOS?

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Jianwei; Hao, Lei [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Li, Aigen, E-mail: haol@shao.ac.cn [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States)

    2014-09-01

    Dust plays a central role in the unification theory of active galactic nuclei (AGNs). However, little is known about the nature (e.g., size, composition) of the dust that forms a torus around the AGN. In this Letter, we report a systematic exploration of the optical extinction (A{sub V} ) and the silicate absorption optical depth (Δτ{sub 9.7}) of 110 type 2 AGNs. We derive A{sub V} from the Balmer decrement based on the Sloan Digital Sky Survey data, and Δτ{sub 9.7} from the Spitzer/InfraRed Spectrograph data. We find that with a mean ratio of (A{sub V} /Δτ{sub 9.7}) ≲ 5.5, the optical-to-silicate extinction ratios of these AGNs are substantially lower than that of the Galactic diffuse interstellar medium (ISM) for which A{sub V} /Δτ{sub 9.7} ≈ 18.5. We argue that the anomalously low A{sub V} /Δτ{sub 9.7} ratio could be due to the predominance of larger grains in the AGN torus compared to that in the Galactic diffuse ISM.

  5. A ∼ 3.8 hr PERIODICITY FROM AN ULTRASOFT ACTIVE GALACTIC NUCLEUS CANDIDATE

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Dacheng; Irwin, Jimmy A. [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States); Godet, Olivier; Webb, Natalie A.; Barret, Didier, E-mail: dlin@ua.edu [CNRS, IRAP, 9 avenue du Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France)

    2013-10-10

    Very few galactic nuclei are found to show significant X-ray quasi-periodic oscillations (QPOs). After carefully modeling the noise continuum, we find that the ∼3.8 hr QPO in the ultrasoft active galactic nucleus candidate 2XMM J123103.2+110648 was significantly detected (∼5σ) in two XMM-Newton observations in 2005, but not in the one in 2003. The QPO root mean square (rms) is very high and increases from ∼25% in 0.2-0.5 keV to ∼50% in 1-2 keV. The QPO probably corresponds to the low-frequency type in Galactic black hole X-ray binaries, considering its large rms and the probably low mass (∼10{sup 5} M {sub ☉}) of the black hole in the nucleus. We also fit the soft X-ray spectra from the three XMM-Newton observations and find that they can be described with either pure thermal disk emission or optically thick low-temperature Comptonization. We see no clear X-ray emission from the two Swift observations in 2013, indicating lower source fluxes than those in XMM-Newton observations.

  6. DO GIANT PLANETS SURVIVE TYPE II MIGRATION?

    International Nuclear Information System (INIS)

    Hasegawa, Yasuhiro; Ida, Shigeru

    2013-01-01

    Planetary migration is one of the most serious problems to systematically understand the observations of exoplanets. We clarify that the theoretically predicted type II, migration (like type I migration) is too fast, by developing detailed analytical arguments in which the timescale of type II migration is compared with the disk lifetime. In the disk-dominated regime, the type II migration timescale is characterized by a local viscous diffusion timescale, while the disk lifetime is characterized by a global diffusion timescale that is much longer than the local one. Even in the planet-dominated regime where the inertia of the planet mass reduces the migration speed, the timescale is still shorter than the disk lifetime except in the final disk evolution stage where the total disk mass decays below the planet mass. This suggests that most giant planets plunge into the central stars within the disk lifetime, and it contradicts the exoplanet observations that gas giants are piled up at r ∼> 1 AU. We examine additional processes that may arise in protoplanetary disks: dead zones, photoevaporation of gas, and gas flow across a gap formed by a type II migrator. Although they make the type II migration timescale closer to the disk lifetime, we show that none of them can act as an effective barrier for rapid type II migration with the current knowledge of these processes. We point out that gas flow across a gap and the fraction of the flow accreted onto the planets are uncertain and they may have the potential to solve the problem. Much more detailed investigation for each process may be needed to explain the observed distribution of gas giants in extrasolar planetary systems

  7. Genetic heterogeneity of Usher syndrome type II.

    OpenAIRE

    Pieke Dahl, S; Kimberling, WJ; Gorin, MB; Weston, MD; Furman, JM; Pikus, A; Moller, C

    1993-01-01

    Usher syndrome is an autosomal recessive disorder characterised by retinitis pigmentosa and congenital sensorineural hearing loss. A gene for Usher syndrome type II (USH2) has been localised to chromosome 1q32-q41. DNA from a family with four of seven sibs affected with clinical characteristics of Usher syndrome type II was genotyped using markers spanning the 1q32-1q41 region. These included D1S70 and D1S81, which are believed to flank USH2. Genotypic results and subsequent linkage analysis ...

  8. Metallicity Variations in the Type II Globular Cluster NGC 6934

    Science.gov (United States)

    Marino, A. F.; Yong, D.; Milone, A. P.; Piotto, G.; Lundquist, M.; Bedin, L. R.; Chené, A.-N.; Da Costa, G.; Asplund, M.; Jerjen, H.

    2018-06-01

    The Hubble Space Telescope photometric survey of Galactic globular clusters (GCs) has revealed a peculiar “chromosome map” for NGC 6934. In addition to a typical sequence, similar to that observed in Type I GCs, NGC 6934 displays additional stars on the red side, analogous to the anomalous Type II GCs, as defined in our previous work. We present a chemical abundance analysis of four red giants in this GC. Two stars are located on the chromosome map sequence common to all GCs, and another two lie on the additional sequence. We find (i) star-to-star Fe variations, with the two anomalous stars being enriched by ∼0.2 dex. Because of our small-size sample, this difference is at the ∼2.5σ level. (ii) There is no evidence for variations in the slow neutron-capture abundances over Fe, at odds with what is often observed in anomalous Type II GCs, e.g., M 22 and ω Centauri (iii) no large variations in light elements C, O, and Na, compatible with locations of the targets on the lower part of the chromosome map where such variations are not expected. Since the analyzed stars are homogeneous in light elements, the only way to reproduce the photometric splits on the sub-giant (SGB) and the red giant (RGB) branches is to assume that red RGB/faint SGB stars are enhanced in [Fe/H] by ∼0.2. This fact corroborates the spectroscopic evidence of a metallicity variation in NGC 6934. The observed chemical pattern resembles only partially the other Type II GCs, suggesting that NGC 6934 might belong either to a third class of GCs, or be a link between normal Type I and anomalous Type II GCs. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile, and Gemini Telescope at Canada–France–Hawaii Telescope.

  9. Synthesis, α-glucosidase inhibitory activity and in silico study of tris-indole hybrid scaffold with oxadiazole ring: As potential leads for the management of type-II diabetes mellitus.

    Science.gov (United States)

    Taha, Muhammad; Rahim, Fazal; Imran, Syahrul; Ismail, Nor Hadiani; Ullah, Hayat; Selvaraj, Manikandan; Javid, Muhammad Tariq; Salar, Uzma; Ali, Muhammad; Khan, Khalid Mohammed

    2017-10-01

    Discovery of α-glucosidase inhibitors has been actively pursued with the aim to develop therapeutics for the treatment of type-II diabetes mellitus and the other carbohydrate mediated disease. In continuation of our drug discovery research on potential antidiabetic agents, we synthesized novel tris-indole-oxadiazole hybrid analogs (1-21), structurally characterized by various spectroscopic techniques such as 1 H NMR, EI-MS, and 13 C NMR. Elemental analysis was found in agreement with the calculated values. All compounds were evaluated for α-glucosidase inhibiting potential and showed potent inhibitory activity in the range of IC 50 =2.00±0.01-292.40±3.16μM as compared to standard acarbose (IC 50 =895.09±2.04µM). The pharmacokinetic predictions of tris-indole series using descriptor properties showed that almost all compounds in this series indicate the drug aptness. Detailed binding mode analyses with docking simulation was also carried out which showed that the inhibitors can be stabilized by the formation of hydrogen bonds with catalytic residues and the establishment of hydrophobic contacts at the opposite side of the active site. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Type II supernovae: How do they explode?

    International Nuclear Information System (INIS)

    Baron, E.

    1988-01-01

    I discuss what has been learned from the neutrino observations of Supernova 1987A. The neutrino detections confirmed our basic theoretical scenario that Type II supernovae involve the gravitational collapse of a massive star. The small number of events makes it difficult to infer details about the actual mechanism of collapse. I discuss the current theoretical situation on the mechanism of explosion

  11. Positron Survival in Type II Supernovae

    Science.gov (United States)

    1989-05-01

    B: Computer Program and Flow Diagram 53 References 59 I. Introduction Since the discovery of Supernova 1987A (a Type II supernova) in February of 1987...the fewer number of decays depositing energy within the supernova. The rate of this cooling is unknown because it is uncertain whether a pulsar was

  12. COMBINING SEMIANALYTIC MODELS WITH SIMULATIONS OF GALAXY CLUSTERS: THE NEED FOR HEATING FROM ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Short, C. J.; Thomas, P. A.

    2009-01-01

    We present hydrodynamical N-body simulations of clusters of galaxies with feedback taken from semianalytic models of galaxy formation. The advantage of this technique is that the source of feedback in our simulations is a population of galaxies that closely resembles that found in the real universe. We demonstrate that, to achieve the high entropy levels found in clusters, active galactic nuclei must inject a large fraction of their energy into the intergalactic/intracluster media throughout the growth period of the central black hole. These simulations reinforce the argument of Bower et al., who arrived at the same conclusion on the basis of purely semianalytic reasoning.

  13. On the contribution of active galactic nuclei to the diffuse X-ray background

    International Nuclear Information System (INIS)

    Avni, Y.

    1977-01-01

    It is shown that cosmological evolution has a pronounced effect on the contributions of active galactic nuclei to the diffuse x-ray background. The dependence of such contributions on the form and amount of density evolution, on the deceleration parameter, and on the formation epoch is found. It is established, in particular, that x-ray Seyferts can account for all of the observed 2-10 keV background when the effects of evolution are considered; the required amount of evolution is intermediate between the evolution of quasars and no evolution. (author)

  14. Exploring Black Hole Accretion in Active Galactic Nuclei with Simbol-X

    Science.gov (United States)

    Goosmann, R. W.; Dovčiak, M.; Mouchet, M.; Czerny, B.; Karas, V.; Gonçalves, A.

    2009-05-01

    A major goal of the Simbol-X mission is to improve our knowledge about black hole accretion. By opening up the X-ray window above 10 keV with unprecedented sensitivity and resolution we obtain new constraints on the X-ray spectral and variability properties of active galactic nuclei. To interpret the future data, detailed X-ray modeling of the dynamics and radiation processes in the black hole vicinity is required. Relativistic effects must be taken into account, which then allow to constrain the fundamental black hole parameters and the emission pattern of the accretion disk from the spectra that will be obtained with Simbol-X.

  15. A new approach for measuring power spectra and reconstructing time series in active galactic nuclei

    Science.gov (United States)

    Li, Yan-Rong; Wang, Jian-Min

    2018-05-01

    We provide a new approach to measure power spectra and reconstruct time series in active galactic nuclei (AGNs) based on the fact that the Fourier transform of AGN stochastic variations is a series of complex Gaussian random variables. The approach parametrizes a stochastic series in frequency domain and transforms it back to time domain to fit the observed data. The parameters and their uncertainties are derived in a Bayesian framework, which also allows us to compare the relative merits of different power spectral density models. The well-developed fast Fourier transform algorithm together with parallel computation enables an acceptable time complexity for the approach.

  16. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    Science.gov (United States)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 μm) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z >~ 1) active galactic nuclei.

  17. On the contribution of active galactic nuclei to the diffuse X-ray background

    International Nuclear Information System (INIS)

    Avni, Y.

    1978-01-01

    We show that cosmological evolution has a pronounced effect on the contributions of active galactic nuclei to the diffuse x-ray background. We find the dependence of such contributions on the form and amount of density evolution, on the deceleration parameter, and on the formation epoch. We find in particular that x-ray Seyferts can account for all of the observed 2-10 keV background when the effects of evolution are considered; the required amount of evolution is intermediate between the evolution of quasars and no evolution. (orig.) [de

  18. On the High-Energy Neutrino Emission from Active Galactic Nuclei

    Directory of Open Access Journals (Sweden)

    Emma Kun

    2018-02-01

    Full Text Available We review observational aspects of the active galactic nuclei and their jets in connection with the detection of high-energy neutrinos by the Antarctic IceCube Neutrino Observatory. We propose that a reoriented jet generated by the spin-flipping supermassive black hole in a binary merger is likely the source of such high-energy neutrinos. Hence they encode important information on the afterlife of coalescing supermassive black hole binaries. As the gravitational radiation emanating from them will be monitored by the future LISA space mission, high-energy neutrino detections could be considered a contributor to multi-messenger astronomy.

  19. Hard X-ray emission mechanism of active galactic nuclei sources

    International Nuclear Information System (INIS)

    Liang, E.P.T.

    1979-01-01

    Within the framework of unsaturated Compton disk accretion onto a supermassive black hole as model for power-law active galactic nuclei X-ray sources (as opposed to the synchro-Compton model), we compare the hot inner disk model of Shapiro, Lightman, and Eardley and the disk corona model with balanced conduction and Compton losses. Both can generate electron temperatures > or approx. =10 9 K in the supermassive case but promise other observable distinctions. The sandwich configuration of the disk corona provides a natural explanation of why Comptonization is unsaturated

  20. A Heuristic Model for the Active Galactic Nucleus Based on the Planck Vacuum Theory

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-07-01

    Full Text Available The standard explanation for an active galactic nucleus (AGN is a "central engine" consisting of a hot accretion disk surrounding a supermassive black hole. Energy is generated by the gravitational infall of material which is heated to high temperatures in this dissipative accretion disk. What follows is an alternative model for the AGN based on the Planck vacuum (PV theory, where both the energy of the AGN and its variable luminosity are explained in terms of a variable photon flux emanating from the PV.

  1. Search for emission of ultra high energy radiation from active galactic nuclei

    International Nuclear Information System (INIS)

    1993-01-01

    A search for emission of ultra-high energy gamma radiation from 13 active galactic nuclei that were detected by EGRET, using the CYGNUS extensive air-shower array, is described. The data set has been searched for continuous emission, emission on the time scale of one week, and for on the time scale of out day. No evidence for emission from any of the AGN on any of the time scales examined was found. The 90% C.L. upper limit to the continuous flux from Mrk 421 above 50 TeV is 7.5 x 10 -14 cm -2 s -1

  2. EVIDENCE FOR WIDESPREAD ACTIVE GALACTIC NUCLEUS ACTIVITY AMONG MASSIVE QUIESCENT GALAXIES AT z ∼ 2

    International Nuclear Information System (INIS)

    Olsen, Karen P.; Rasmussen, Jesper; Toft, Sune; Zirm, Andrew W.

    2013-01-01

    We quantify the presence of active galactic nuclei (AGNs) in a mass-complete (M * > 5 × 10 10 M ☉ ) sample of 123 star-forming and quiescent galaxies at 1.5 ≤ z ≤ 2.5, using X-ray data from the 4 Ms Chandra Deep Field-South (CDF-S) survey. 41% ± 7% of the galaxies are detected directly in X-rays, 22% ± 5% with rest-frame 0.5-8 keV luminosities consistent with hosting luminous AGNs (L 0.5-8keV > 3 × 10 42 erg s –1 ). The latter fraction is similar for star-forming and quiescent galaxies, and does not depend on galaxy stellar mass, suggesting that perhaps luminous AGNs are triggered by external effects such as mergers. We detect significant mean X-ray signals in stacked images for both the individually non-detected star-forming and quiescent galaxies, with spectra consistent with star formation only and/or a low-luminosity AGN in both cases. Comparing star formation rates inferred from the 2-10 keV luminosities to those from rest-frame IR+UV emission, we find evidence for an X-ray excess indicative of low-luminosity AGNs. Among the quiescent galaxies, the excess suggests that as many as 70%-100% of these contain low- or high-luminosity AGNs, while the corresponding fraction is lower among star-forming galaxies (43%-65%). Our discovery of the ubiquity of AGNs in massive, quiescent z ∼ 2 galaxies provides observational support for the importance of AGNs in impeding star formation during galaxy evolution.

  3. New structures of power density spectra for four Kepler active galactic nuclei

    Science.gov (United States)

    Dobrotka, A.; Antonuccio-Delogu, V.; Bajčičáková, I.

    2017-09-01

    Many nearby active galactic nuclei display a significant short-term variability. In this work, we reanalyse photometric data of four active galactic nuclei observed by Kepler in order to study the flickering activity, with our main goal to search for multiple components in the power density spectra. We find that all four objects have similar characteristics, with two break frequencies at approximately log( f /Hz) = -5.2 and -4.7. We consider some physical phenomena whose characteristic time-scales are consistent with those observed, in particular mass accretion fluctuations in the inner geometrically thick disc (hot X-ray corona) and unstable relativistic Rayleigh-Taylor modes. The former is supported by detection of the same break frequencies in the Swift X-ray data of ZW229-15. We also discuss rms-flux relations, and we detect a possible typical linear trend at lower flux levels. Our findings support the hypothesis of a multiplicative character of variability, in agreement with the propagating accretion fluctuation model.

  4. Characterization of cloned cells from an immortalized fetal pulmonary type II cell line

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, R.F.; Waide, J.J.; Lechner, J.F.

    1995-12-01

    A cultured cell line that maintained expression of pulmonary type II cell markers of differentiation would be advantageous to generate a large number of homogenous cells in which to study the biochemical functions of type II cells. Type II epithelial cells are the source of pulmonary surfactant and a cell of origin for pulmonary adenomas. Last year our laboratory reported the induction of expression of two phenotypic markers of pulmonary type II cells (alkaline phosphatase activity and surfactant lipid synthesis) in cultured fetal rat lung epithelial (FRLE) cells, a spontaneously immortalized cell line of fetal rat lung type II cell origin. Subsequently, the induction of the ability to synthesize surfactant lipid became difficult to repeat. We hypothesized that the cell line was heterogenuous and some cells were more like type II cells than others. The purpose of this study was to test this hypothesis and to obtain a cultured cell line with type II cell phenotypic markers by cloning several FRLE cells and characterizing them for phenotypic markers of type II cells (alkaline phosphatase activity and presence of surfactant lipids). Thirty cloned cell lines were analyzed for induced alkaline phosphatase activity (on x-axis) and for percent of phospholipids that were disaturated (i.e., surfactant).

  5. Analysis of nearly simultaneous x-ray and optical observations of active galactic nuclei

    International Nuclear Information System (INIS)

    Webb, J.R.

    1988-01-01

    Rosemary Hill optical and EINSTEIN X-ray observations of a sample of 36 galactic nuclei (AGN) were reduced and analyzed. Seventy-two x-ray observations of these sources were reduced, nineteen of which yielded spectral information. Of these spectra observations, significant hydrogen column densities above the galactic value were required for nine of the active galactic nuclei. X-ray variability was detected in eight of the eleven sources which were observed more than once by EINSTEIN. Correlations between the x-ray and optical luminosities were investigated using the Jefferys method of least squares. This method allows for errors in both variables. The results indicate a strong correlation between the x-ray and optical luminosities for the entire sample. Division of the sample into groups with similar optical variability characteristics show that the less violently violent variable AGN are more highly correlated than the violently variable blazars. Infrared and radio observations were combined with the x-ray and optical observations of six AGN. These sources were modelled in terms of the synchrotron-self-Compton model. The turnover frequency falls between the infrared and radio data and reliable estimates of this parameter are difficult to estimate. Therefore the results were found as a function of the turnover frequency. Four sources required relativistic bulk motion or beaming. Multifrequency spectra made at different times for one individual source, 0235+164, required different amounts of beaming to satisfy the x-ray observations. Sizes of the emitting regions for the sources modelled ranged from 0.5 parsec to 1.0 parsec

  6. Neutrino-heated stars and broad-line emission from active galactic nuclei

    Science.gov (United States)

    Macdonald, James; Stanev, Todor; Biermann, Peter L.

    1991-01-01

    Nonthermal radiation from active galactic nuclei indicates the presence of highly relativistic particles. The interaction of these high-energy particles with matter and photons gives rise to a flux of high-energy neutrinos. In this paper, the influence of the expected high neutrino fluxes on the structure and evolution of single, main-sequence stars is investigated. Sequences of models of neutrino-heated stars in thermal equilibrium are presented for masses 0.25, 0.5, 0.8, and 1.0 solar mass. In addition, a set of evolutionary sequences for mass 0.5 solar mass have been computed for different assumed values for the incident neutrino energy flux. It is found that winds driven by the heating due to high-energy particles and hard electromagnetic radiation of the outer layers of neutrino-bloated stars may satisfy the requirements of the model of Kazanas (1989) for the broad-line emission clouds in active galactic nuclei.

  7. LOCAL LUMINOUS INFRARED GALAXIES. II. ACTIVE GALACTIC NUCLEUS ACTIVITY FROM SPITZER/INFRARED SPECTROGRAPH SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Herrero, Almudena; Pereira-Santaella, Miguel [Centro de Astrobiologia, INTA-CSIC, E-28850 Torrejon de Ardoz, Madrid (Spain); Rieke, George H. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Rigopoulou, Dimitra [Astrophysics Department, University of Oxford, Oxford OX1 3RH (United Kingdom)

    2012-01-01

    We quantify the active galactic nucleus (AGN) contribution to the mid-infrared (mid-IR) and the total infrared (IR, 8-1000 {mu}m) emission in a complete volume-limited sample of 53 local luminous infrared galaxies (LIRGs, L{sub IR} = 10{sup 11}-10{sup 12} L{sub Sun }). We decompose the Spitzer Infrared Spectrograph low-resolution 5-38 {mu}m spectra of the LIRGs into AGN and starburst components using clumpy torus models and star-forming galaxy templates, respectively. We find that 50% (25/50) of local LIRGs have an AGN component detected with this method. There is good agreement between these AGN detections through mid-IR spectral decomposition and other AGN indicators, such as the optical spectral class, mid-IR spectral features, and X-ray properties. Taking all the AGN indicators together, the AGN detection rate in the individual nuclei of LIRGs is {approx}62%. The derived AGN bolometric luminosities are in the range L{sub bol}(AGN) = (0.4-50) Multiplication-Sign 10{sup 43} erg s{sup -1}. The AGN bolometric contribution to the IR luminosities of the galaxies is generally small, with 70% of LIRGs having L{sub bol}[AGN]/L{sub IR} {<=} 0.05. Only {approx_equal} 8% of local LIRGs have a significant AGN bolometric contribution L{sub bol}[AGN]/L{sub IR} > 0.25. From the comparison of our results with literature results of ultraluminous infrared galaxies (L{sub IR} = 10{sup 12}-10{sup 13} L{sub Sun }), we confirm that in the local universe the AGN bolometric contribution to the IR luminosity increases with the IR luminosity of the galaxy/system. If we add up the AGN bolometric luminosities we find that AGNs only account for 5%{sub -3%}{sup +8%} of the total IR luminosity produced by local LIRGs (with and without AGN detections). This proves that the bulk of the IR luminosity of local LIRGs is due to star formation activity. Taking the newly determined IR luminosity density of LIRGs in the local universe, we then estimate an AGN IR luminosity density of {Omega}{sup AGN

  8. MID-INFRARED SELECTION OF ACTIVE GALACTIC NUCLEI WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER. I. CHARACTERIZING WISE-SELECTED ACTIVE GALACTIC NUCLEI IN COSMOS

    International Nuclear Information System (INIS)

    Stern, Daniel; Assef, Roberto J.; Eisenhardt, Peter; Benford, Dominic J.; Blain, Andrew; Cutri, Roc; Griffith, Roger L.; Jarrett, T. H.; Masci, Frank; Tsai, Chao-Wei; Yan, Lin; Dey, Arjun; Lake, Sean; Petty, Sara; Wright, E. L.; Stanford, S. A.; Harrison, Fiona; Madsen, Kristin

    2012-01-01

    The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 – W2 ≥ 0.8 (i.e., [3.4]–[4.6] ≥0.8, Vega), which identifies 61.9 ± 5.4 active galactic nucleus (AGN) candidates per deg 2 to a depth of W2 ∼ 15.0. This implies a much larger census of luminous AGNs than found by typical wide-area surveys, attributable to the fact that mid-infrared selection identifies both unobscured (type 1) and obscured (type 2) AGNs. Optical and soft X-ray surveys alone are highly biased toward only unobscured AGNs, while this simple WISE selection likely identifies even heavily obscured, Compton-thick AGNs. Using deep, public data in the COSMOS field, we explore the properties of WISE-selected AGN candidates. At the mid-infrared depth considered, 160 μJy at 4.6 μm, this simple criterion identifies 78% of Spitzer mid-infrared AGN candidates according to the criteria of Stern et al. and the reliability is 95%. We explore the demographics, multiwavelength properties and redshift distribution of WISE-selected AGN candidates in the COSMOS field.

  9. Scalar dark matter with type II seesaw

    Directory of Open Access Journals (Sweden)

    Arnab Dasgupta

    2014-12-01

    Full Text Available We study the possibility of generating tiny neutrino mass through a combination of type I and type II seesaw mechanism within the framework of an abelian extension of standard model. The model also provides a naturally stable dark matter candidate in terms of the lightest neutral component of a scalar doublet. We compute the relic abundance of such a dark matter candidate and also point out how the strength of type II seesaw term can affect the relic abundance of dark matter. Such a model which connects neutrino mass and dark matter abundance has the potential of being verified or ruled out in the ongoing neutrino, dark matter, as well as accelerator experiments.

  10. Type II first branchial cleft anomaly.

    Science.gov (United States)

    Al-Mahdi, Akmam H; Al-Khurri, Luay E; Atto, Ghada Z; Dhaher, Ameer

    2013-01-01

    First branchial cleft anomaly is a rare disease of the head and neck. It accounts for less than 8% of all branchial abnormalities. It is classified into type I, which is thought to arise from the duplication of the membranous external ear canal and are composed of ectoderm only, and type II that have ectoderm and mesoderm. Because of its rarity, first branchial cleft anomaly is often misdiagnosed and results in inappropriate management. A 9-year-old girl presented to us with fistula in the submandibular region and discharge in the external ear. Under general anesthesia, complete surgical excision of the fistula tract was done through step-ladder approach, and the histopathologic examination confirmed the diagnosis of type II first branchial cleft anomaly.

  11. Photometric properties of type II supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Barbon, R [Osservatorio Astrofisico, Asiago (Italy); Trieste Univ. (Italy). Instituto di Matematica); Ciatti, F; Rosino, L [Osservatorio Astrofisico, Asiago (Italy); Pavia Univ. (Italy))

    1979-02-01

    An analysis of the available photometric observations for type II supernovae is presented. The possibility of drawing average curves by the fitting method, as previously done for type I supernovae, is indicated. Two basic shapes have been put into evidence, the first one (2/3 of the objects) is characterized by the presence of a plateau at intermediate phase, the second one by an almost linear decline. Average curves have been also built for the intrinsic color indices. Peculiar cases are discussed, including the unusual objects of types III-IV. The mean absolute magnitude at maximum for type II supernovae has been determined about Msub(B) = -16.45 (sigma=0.78), as a calibration for their use as distance indicators. The distribution in different morphological types and luminosity classes of the parent galaxies is briefly discussed.

  12. [Mania associated with Usher syndrome type II].

    Science.gov (United States)

    Praharaj, Samir Kumar; Acharya, Mahima; Sarvanan, Arul; Kongasseri, Sreejayan; Behere, Rishikesh V; Sharma, P S V N

    2012-01-01

    Usher syndrome (or Hallgren syndrome) is an autosomal recessive genetic disorder characterized by sensorineural deafness, retinitis pigmentosa, and variable vestibular deficit; Usher syndrome type II is the most common form. Various neuropsychiatric disorders have been reported to occur in those with Usher syndrome, including schizophrenia-like disorder, atypical psychosis, recurrent depressive illness, neurotic disorder, and mental retardation; however, bipolar disorder is not common in those with Usher syndrome. Herein we describe a 30-year-old male with Usher syndrome type II that developed features indicative of a probable manic episode. The patient had complete remission of symptoms in response to treatment with olanzapine 20 mg d-1. In persons with dual sensory impairment there are inherent problems with assessment and diagnosis is difficult due to their limited communication abilities. The diagnosis of Usher syndrome depends heavily on behavioral observation and disturbances in vegetative functions.

  13. Chiari Type II malformation: Prenatal sonographic findings

    Directory of Open Access Journals (Sweden)

    Sadhanandham Shrinuvasan

    2015-01-01

    Full Text Available Chiari malformations (CM are a group of defects associated with the congenital caudal displacement of the cerebellum and brainstem. A thorough understanding of the sonographic findings is necessary for the diagnosis of CM in the developing fetus. Here, we present the classical imaging findings of CM Type II detected in a 25-year-old primigravida at 26 weeks of gestation by routine sonographic screening.

  14. Aase-Smith Syndrome type II

    International Nuclear Information System (INIS)

    Soker, Murat; Ayyildiz, Orhan; Isikdogan, Abdurrahman

    2004-01-01

    Aase-Smith syndrome type II is a rare in childhood and there a few reported cases. Here, we report an 8-months-old boy with congenital red cell aplasia and triphalangeal thumbs. In addition to thumb anomalies. He presented with growth failure, hypertelorism and novel osseous radiologic abnormalities, large fontanelles and micrognathia as extraordinary. Some clinical symptoms had complete clinical remission with deflazacort treatment. (author)

  15. Exciton in type-II quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Sierra-Ortega, J; Escorcia, R A [Universidad del Magdalena, A. A. 731, Santa Marta (Colombia); Mikhailov, I D, E-mail: jsierraortega@gmail.co [Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia)

    2009-05-01

    We study the quantum-size effect and the influence of the external magnetic field on the exciton ground state energy in the type-II InP quantum disk, lens and pyramid deposited on a wetting layer and embedded in a GaInP matrix. We show that the charge distribution over and below quantum dot and wetting layer induced by trapped exciton strongly depends on the quantum dot morphology and the strength of the magnetic field.

  16. Autosomal Dominant Growth Hormone Deficiency (Type II).

    Science.gov (United States)

    Alatzoglou, Kyriaki S; Kular, Dalvir; Dattani, Mehul T

    2015-06-01

    Isolated growth hormone deficiency (IGHD) is the commonest pituitary hormone deficiency resulting from congenital or acquired causes, although for most patients its etiology remains unknown. Among the known factors, heterozygous mutations in the growth hormone gene (GH1) lead to the autosomal dominant form of GHD, also known as type II GHD. In many cohorts this is the commonest form of congenital isolated GHD and is mainly caused by mutations that affect the correct splicing of GH-1. These mutations cause skipping of the third exon and lead to the production of a 17.5-kDa GH isoform that exerts a dominant negative effect on the secretion of the wild type GH. The identification of these mutations has clinical implications for the management of patients, as there is a well-documented correlation between the severity of the phenotype and the increased expression of the 17.5-kDa isoform. Patients with type II GHD have a variable height deficit and severity of GHD and may develop additional pituitary hormone defiencies over time, including ACTH, TSH and gonadotropin deficiencies. Therefore, their lifelong follow-up is recommended. Detailed studies on the effect of heterozygous GH1 mutations on the trafficking, secretion and action of growth hormone can elucidate their mechanism on a cellular level and may influence future treatment options for GHD type II.

  17. Black hole variability and the star formation-active galactic nucleus connection: Do all star-forming galaxies host an active galactic nucleus?

    International Nuclear Information System (INIS)

    Hickox, Ryan C.; Chen, Chien-Ting J.; Civano, Francesca M.; Hainline, Kevin N.; Mullaney, James R.; Alexander, David M.; Goulding, Andy D.

    2014-01-01

    We investigate the effect of active galactic nucleus (AGN) variability on the observed connection between star formation and black hole accretion in extragalactic surveys. Recent studies have reported relatively weak correlations between observed AGN luminosities and the properties of AGN hosts, which has been interpreted to imply that there is no direct connection between AGN activity and star formation. However, AGNs may be expected to vary significantly on a wide range of timescales (from hours to Myr) that are far shorter than the typical timescale for star formation (≳100 Myr). This variability can have important consequences for observed correlations. We present a simple model in which all star-forming galaxies host an AGN when averaged over ∼100 Myr timescales, with long-term average AGN accretion rates that are perfectly correlated with the star formation rate (SFR). We show that reasonable prescriptions for AGN variability reproduce the observed weak correlations between SFR and L AGN in typical AGN host galaxies, as well as the general trends in the observed AGN luminosity functions, merger fractions, and measurements of the average AGN luminosity as a function of SFR. These results imply that there may be a tight connection between AGN activity and SFR over galaxy evolution timescales, and that the apparent similarities in rest-frame colors, merger rates, and clustering of AGNs compared to 'inactive' galaxies may be due primarily to AGN variability. The results provide motivation for future deep, wide extragalactic surveys that can measure the distribution of AGN accretion rates as a function of SFR.

  18. Magnetic activity in the Galactic Centre region - fast downflows along rising magnetic loops

    Science.gov (United States)

    Kakiuchi, Kensuke; Suzuki, Takeru K.; Fukui, Yasuo; Torii, Kazufumi; Enokiya, Rei; Machida, Mami; Matsumoto, Ryoji

    2018-06-01

    We studied roles of the magnetic field on the gas dynamics in the Galactic bulge by a three-dimensional global magnetohydrodynamical simulation data, particularly focusing on vertical flows that are ubiquitously excited by magnetic activity. In local regions where the magnetic field is stronger, it is frequently seen that fast downflows slide along inclined magnetic field lines that are associated with buoyantly rising magnetic loops. The vertical velocity of these downflows reaches ˜100 km s-1 near the footpoint of the loops by the gravitational acceleration towards the Galactic plane. The two footpoints of rising magnetic loops are generally located at different radial locations and the field lines are deformed by the differential rotation. The angular momentum is transported along the field lines, and the radial force balance breaks down. As a result, a fast downflow is often observed only at the one footpoint located at the inner radial position. The fast downflow compresses the gas to form a dense region near the footpoint, which will be important in star formation afterwards. Furthermore, the horizontal components of the velocity are also fast near the footpoint because the downflow is accelerated along the magnetic sliding slope. As a result, the high-velocity flow creates various characteristic features in a simulated position-velocity diagram, depending on the viewing angle.

  19. A SCALING RELATION BETWEEN MEGAMASER DISK RADIUS AND BLACK HOLE MASS IN ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Wardle, Mark; Yusef-Zadeh, Farhad

    2012-01-01

    Several thin, Keplerian, sub-parsec megamaser disks have been discovered in the nuclei of active galaxies and used to precisely determine the mass of their host black holes. We show that there is an empirical linear correlation between the disk radius and the black hole mass. We demonstrate that such disks are naturally formed by the partial capture of molecular clouds passing through the galactic nucleus and temporarily engulfing the central supermassive black hole. Imperfect cancellation of the angular momenta of the cloud material colliding after passing on opposite sides of the hole leads to the formation of a compact disk. The radial extent of the disk is determined by the efficiency of this process and the Bondi-Hoyle capture radius of the black hole, and naturally produces the empirical linear correlation of the radial extent of the maser distribution with black hole mass. The disk has sufficient column density to allow X-ray irradiation from the central source to generate physical and chemical conditions conducive to the formation of 22 GHz H 2 O masers. For initial cloud column densities ∼ 23.5 cm –2 the disk is non-self-gravitating, consistent with the ordered kinematics of the edge-on megamaser disks; for higher cloud columns the disk would fragment and produce a compact stellar disk similar to that observed around Sgr A* at the galactic center.

  20. Dynamic radio bursts associated with important flare activity in Hale region 16923 and the problem of the relative locations of type II 'slow drift' bursts and coronal transients

    Energy Technology Data Exchange (ETDEWEB)

    Mckenna-Lawlor, S.M.P.

    1983-03-01

    Seven type-II radio bursts associated with solar flares in the Hale region 16923 on June 27-29, 1980, are characterized on the basis of data from dynamic radio spectra, white-light observations, radioheliograms, SMM-C/P observations, and Helios I magnetic-field and solar-wind measurements. The data are summarized in tables and graphs and discussed in terms of transient events occurring in the same region. The magnetic shock waves recorded during the period by Helios are described, and channeling effects which may have prevented the detection of type-II burst shocks are examined.

  1. An updated Type II supernova Hubble diagram

    Science.gov (United States)

    Gall, E. E. E.; Kotak, R.; Leibundgut, B.; Taubenberger, S.; Hillebrandt, W.; Kromer, M.; Burgett, W. S.; Chambers, K.; Flewelling, H.; Huber, M. E.; Kaiser, N.; Kudritzki, R. P.; Magnier, E. A.; Metcalfe, N.; Smith, K.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

    2018-03-01

    We present photometry and spectroscopy of nine Type II-P/L supernovae (SNe) with redshifts in the 0.045 ≲ z ≲ 0.335 range, with a view to re-examining their utility as distance indicators. Specifically, we apply the expanding photosphere method (EPM) and the standardized candle method (SCM) to each target, and find that both methods yield distances that are in reasonable agreement with each other. The current record-holder for the highest-redshift spectroscopically confirmed supernova (SN) II-P is PS1-13bni (z = 0.335-0.012+0.009), and illustrates the promise of Type II SNe as cosmological tools. We updated existing EPM and SCM Hubble diagrams by adding our sample to those previously published. Within the context of Type II SN distance measuring techniques, we investigated two related questions. First, we explored the possibility of utilising spectral lines other than the traditionally used Fe IIλ5169 to infer the photospheric velocity of SN ejecta. Using local well-observed objects, we derive an epoch-dependent relation between the strong Balmer line and Fe IIλ5169 velocities that is applicable 30 to 40 days post-explosion. Motivated in part by the continuum of key observables such as rise time and decline rates exhibited from II-P to II-L SNe, we assessed the possibility of using Hubble-flow Type II-L SNe as distance indicators. These yield similar distances as the Type II-P SNe. Although these initial results are encouraging, a significantly larger sample of SNe II-L would be required to draw definitive conclusions. Tables A.1, A.3, A.5, A.7, A.9, A.11, A.13, A.15 and A.17 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A25

  2. The Fermi LAT Very Important Project (VIP) List of Active Galactic Nuclei

    Science.gov (United States)

    Thompson, David J.; Fermi Large Area Telescope Collaboration

    2018-01-01

    Using nine years of Fermi Gamma-ray Space Telescope Large Area Telescope (LAT) observations, we have identified 30 projects for Active Galactic Nuclei (AGN) that appear to provide strong prospects for significant scientific advances. This Very Important Project (VIP) AGN list includes AGNs that have good multiwavelength coverage, are regularly detected by the Fermi LAT, and offer scientifically interesting timing or spectral properties. Each project has one or more LAT scientists identified who are actively monitoring the source. They will be regularly updating the LAT results for these VIP AGNs, working together with multiwavelength observers and theorists to maximize the scientific return during the coming years of the Fermi mission. See https://confluence.slac.stanford.edu/display/GLAMCOG/VIP+List+of+AGNs+for+Continued+Study

  3. Photon damping in cosmic-ray acceleration in active galactic nuclei

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1983-01-01

    The usual assumption of the acceleration of ultra high energy cosmic rays, greater than or equal to 10 18 eV in quasars, Seyfert galaxies and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10 20 eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10 15 . Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultra high energy. Hence, it is unlikely that any reasonable configuration of acceleration can void disastrous photon energy loss. A different site for ultra high energy cosmic ray acceleration must be found

  4. Extragalactic Background Light expected from photon-photon absorption on spectra of distant Active Galactic Nuclei

    International Nuclear Information System (INIS)

    Sinitsyna, V. G.; Sinitsyna, V. Y.

    2013-01-01

    Extragalactic background radiation blocks the propagation of TeV gamma-ray over large distances by producing e + e - pairs. As a result, primary spectrum of gamma-source is changed, depending on spectrum of background light. So, hard spectra of Active Galactic Nuclei with high red shifts allow the determination of a EBL spectrum. The redshifts of SHALON TeV gamma-ray sources range from 0.018 to 1.375 those spectra are resolved at the energies from 800 GeV to 30 TeV. Spectral energy distribution of EBL constrained from observations of Mkn421 (z=0.031), Mkn501 (z=0.034), Mkn180 (z=0.046), OJ287 (z=0.306), 3c454.3 (z=0.859) and 1739+5220(z=1.375) together with models and measurements are presented. (authors)

  5. Nonthermal electron-positron pairs and cold matter in the central engines of active galactic nuclei

    Science.gov (United States)

    Zdziarski, Andrzej A.

    1992-01-01

    The nonthermal e(+/-) pair model of the central engine of active galactic nuclei (AGNs) is discussed. The model assumes that nonthermal e(+/-) pairs are accelerated to highly relativistic energies in a compact region close to the central black hole and in the vicinity of some cold matter. The model has a small number of free parameters and explains a large body of AGN observations from EUV to soft gamma-rays. In particular, the model explains the existence of the UV bump, the soft X-rays excess, the canonical hard X-ray power law, the spectral hardening above about 10 keV, and some of the variability patterns in the soft and hard X-rays. In addition, the model explains the spectral steepening above about 50 keV seen in NGC 4151.

  6. THE EFFECTS OF X-RAY FEEDBACK FROM ACTIVE GALACTIC NUCLEI ON HOST GALAXY EVOLUTION

    International Nuclear Information System (INIS)

    Hambrick, D. Clay; Ostriker, Jeremiah P.; Naab, Thorsten; Johansson, Peter H.

    2011-01-01

    Hydrodynamic simulations of galaxies with active galactic nuclei (AGNs) have typically employed feedback that is purely local, i.e., an injection of energy to the immediate neighborhood of the black hole (BH). We perform GADGET-2 simulations of massive elliptical galaxies with an additional feedback component: an observationally calibrated X-ray radiation field which emanates from the BH and heats gas out to large radii from the galaxy center. We find that including the heating and radiation pressure associated with this X-ray flux in our simulations enhances the effects which are commonly reported from AGN feedback. This new feedback model is twice as effective as traditional feedback at suppressing star formation, produces three times less star formation in the last 6 Gyr, and modestly lowers the final BH mass (30%). It is also significantly more effective than an X-ray background in reducing the number of satellite galaxies.

  7. Measuring type II stresses using 3DXRD

    DEFF Research Database (Denmark)

    Oddershede, Jette; Schmidt, Søren; Poulsen, Henning Friis

    2010-01-01

    An algorithm is presented for characterization of the grain resolved (type II) stress states in a polycrystalline sample based on monochromatic X-ray diffraction data. The algorithm is a robust 12-parameter-per-grain fit of the centre-of-mass grain positions, orientations and stress tensors...... including error estimation and outlier rejection. As examples of use results from two experiments – one on interstitial free (IF) steel and one on copper – will be presented. In the first experiment 96 grains in one layer of IF steel were monitored during elastic loading and unloading. Very consistent...

  8. SDSS-IV MaNGA: Galaxy Pair Fraction and Correlated Active Galactic Nuclei

    Science.gov (United States)

    Fu, Hai; Steffen, Joshua L.; Gross, Arran C.; Dai, Y. Sophia; Isbell, Jacob W.; Lin, Lihwai; Wake, David; Xue, Rui; Bizyaev, Dmitry; Pan, Kaike

    2018-04-01

    We have identified 105 galaxy pairs at z ∼ 0.04 with the MaNGA integral-field spectroscopic data. The pairs have projected separations between 1 and 30 kpc, and are selected to have radial velocity offsets less than 600 km s‑1 and stellar mass ratio between 0.1 and 1. The pair fraction increases with both the physical size of the integral-field unit and the stellar mass, consistent with theoretical expectations. We provide the best-fit analytical function of the pair fraction and find that ∼3% of M* galaxies are in close pairs. For both isolated galaxies and paired galaxies, active galactic nuclei (AGNs) are selected using emission-line ratios and Hα equivalent widths measured inside apertures at a fixed physical size. We find AGNs in ∼24% of the paired galaxies and binary AGNs in ∼13% of the pairs. To account for the selection biases in both the pair sample and the MaNGA sample, we compare the AGN comoving volume densities with those expected from the mass- and redshift-dependent AGN fractions. We find a strong (∼5×) excess of binary AGNs over random pairing and a mild (∼20%) deficit of single AGNs. The binary AGN excess increases from ∼2× to ∼6× as the projected separation decreases from 10–30 to 1–10 kpc. Our results indicate that the pairing of galaxies preserves the AGN duty cycle in individual galaxies but increases the population of binary AGNs through correlated activities. We suggest tidally induced galactic-scale shocks and AGN cross-ionization as two plausible channels to produce low-luminosity narrow-line-selected binary AGNs.

  9. Active Galactic Videos: A YouTube Channel for Astronomy Education and Outreach

    Science.gov (United States)

    Calahan, Jenny; Gibbs, Aidan; Hardegree-Ullman, Melody; Hardegree-Ullman, Michael; Impey, Chris David; Kevis, Charlotte; Lewter, Austin; Mauldin, Emmalee; McKee, Carolyn; Olmedo, Alejandro; Pereira, Victoria; Thomas, Melissa; Wenger, Matthew

    2018-01-01

    Active Galactic Videos is an astronomy-focused YouTube channel run by a team at the University of Arizona. The channel both produces astronomy-focused educational content for public audiences and opens a window into the world of professional astronomy by showcasing the work done at Steward Observatory and in Southern Arizona. The channel is mainly run by undergraduate students from a variety of backgrounds including: astronomy, education, film, music, english, and writing. In addition to providing educational content for public audiences, this project provides opportunities for undergraduate students to learn about astronomy content, general astronomy pedagogy, as well as science communication. This is done through developing the practical skills needed to take on the challenge of creating effective and engaging videos. Students write, film, score, direct, and edit each video while conscious of how each piece can affect the teaching/storytelling of the concept at hand. The team has produced various styles of video: presentational, interviews, musical/poetic, tours, and documentaries. In addition to YouTube, the Active Galactic Videos team maintains a social media presence on Facebook, Twitter, and Instagram. These help to widely distribute the content as well as to publicize the main Youtube channel. In addition to providing an overview of our educational work, we present 51 videos, or two year's, worth of online analytics that we are using to better understand our audience, to examine what videos have been popular and successful, and how people are accessing our content. We will present our experience in order to help others learn about improving astronomy education online, as well as astronomy communication and outreach in general.We acknowledge the Howard Hughes Medical Institute for grant support of this and related education initiatives

  10. ON THE SCATTER IN THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Kilerci Eser, E.; Vestergaard, M. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Peterson, B. M.; Denney, K. D. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bentz, M. C., E-mail: ecekilerci@dark-cosmology.dk, E-mail: vester@dark-cosmology.dk, E-mail: kelly@astronomy.ohio-state.edu, E-mail: peterson@astronomy.ohio-state.edu, E-mail: bentz@chara.gsu.edu [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States)

    2015-03-01

    We investigate and quantify the observed scatter in the empirical relationship between the broad line region size R and the luminosity of the active galactic nucleus, in order to better understand its origin. This study is motivated by the indispensable role of this relationship in the mass estimation of cosmologically distant black holes, but may also be relevant to the recently proposed application of this relationship for measuring cosmic distances. We study six nearby reverberation-mapped active galactic nuclei (AGNs) for which simultaneous UV and optical monitoring data exist. We also examine the long-term optical luminosity variations of the Seyfert 1 galaxy NGC 5548 and employ Monte Carlo simulations to study the effects of the intrinsic variability of individual objects on the scatter in the global relationship for a sample of ∼40 AGNs. We find the scatter in this relationship has a correctable dependence on color. For individual AGNs, the size of the Hβ emitting region has a steeper dependence on the nuclear optical luminosity than on the UV luminosity, which can introduce a scatter of ∼0.08 dex into the global relationship, due the nonlinear relationship between the variations in the ionizing continuum and those in the optical continuum. Also, our analysis highlights the importance of understanding and minimizing the scatter in the relationship traced by the intrinsic variability of individual AGNs since it propagates directly into the global relationship. We find that using the UV luminosity as a substitute for the ionizing luminosity can reduce a sizable fraction of the current observed scatter of ∼0.13 dex.

  11. ON THE SCATTER IN THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Kilerci Eser, E.; Vestergaard, M.; Peterson, B. M.; Denney, K. D.; Bentz, M. C.

    2015-01-01

    We investigate and quantify the observed scatter in the empirical relationship between the broad line region size R and the luminosity of the active galactic nucleus, in order to better understand its origin. This study is motivated by the indispensable role of this relationship in the mass estimation of cosmologically distant black holes, but may also be relevant to the recently proposed application of this relationship for measuring cosmic distances. We study six nearby reverberation-mapped active galactic nuclei (AGNs) for which simultaneous UV and optical monitoring data exist. We also examine the long-term optical luminosity variations of the Seyfert 1 galaxy NGC 5548 and employ Monte Carlo simulations to study the effects of the intrinsic variability of individual objects on the scatter in the global relationship for a sample of ∼40 AGNs. We find the scatter in this relationship has a correctable dependence on color. For individual AGNs, the size of the Hβ emitting region has a steeper dependence on the nuclear optical luminosity than on the UV luminosity, which can introduce a scatter of ∼0.08 dex into the global relationship, due the nonlinear relationship between the variations in the ionizing continuum and those in the optical continuum. Also, our analysis highlights the importance of understanding and minimizing the scatter in the relationship traced by the intrinsic variability of individual AGNs since it propagates directly into the global relationship. We find that using the UV luminosity as a substitute for the ionizing luminosity can reduce a sizable fraction of the current observed scatter of ∼0.13 dex

  12. Bronchoalveolar lavage fluid from normal rats stimulates DNA synthesis in rat alveolar type II cells

    International Nuclear Information System (INIS)

    Leslie, C.C.; McCormick-Shannon, K.; Mason, R.J.

    1989-01-01

    Proliferation of alveolar type II cells after lung injury is important for the restoration of the alveolar epithelium. Bronchoalveolar lavage fluid (BALF) may represent an important source of growth factors for alveolar type II cells. To test this possibility, BALF fluid was collected from normal rats, concentrated 10-fold by Amicon filtration, and tested for its ability to stimulate DNA synthesis in rat alveolar type II cells in primary culture. BALF induced a dose-dependent increase in type II cell DNA synthesis resulting in a 6-fold increase in [3H]thymidine incorporation. Similar doses also stimulated [3H]thymidine incorporation into rat lung fibroblasts by 6- to 8-fold. Removal of pulmonary surface active material by centrifugation did not significantly reduce the stimulatory activity of BALF for type II cells. The stimulation of type II cell DNA synthesis by BALF was reduced by 100% after heating at 100 degrees C for 10 min, and by approximately 80% after reduction with dithiothreitol, and after trypsin treatment. Dialysis of BALF against 1 N acetic acid resulted in a 27% reduction in stimulatory activity. The effect of BALF in promoting type II cell DNA synthesis was more pronounced when tested in the presence of serum, although serum itself has very little effect on type II cell DNA synthesis. When BALF was tested in combination with other substances that stimulate type II cell DNA synthesis (cholera toxin, insulin, epidermal growth factor, and acidic fibroblast growth factor), additive effects or greater were observed. When BALF was chromatographed over Sephadex G150, the activity eluted with an apparent molecular weight of 100 kDa

  13. The structure of the broad-line region in active galactic nuclei. I. Reconstructed velocity-delay maps

    DEFF Research Database (Denmark)

    Grier, C.J.; Peterson, B.M.; Pogge, R.W.

    2013-01-01

    We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velo...

  14. NUCLEAR RADIO JET FROM A LOW-LUMINOSITY ACTIVE GALACTIC NUCLEUS IN NGC 4258

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Kohno, Kotaro [Institute of Astronomy, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Nakanishi, Kouichiro [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kameno, Seiji [Department of Physics, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan); Inoue, Makoto [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Hada, Kazuhiro [INAF, Istituto di Radioastronomia, via Gobetti 101, Bologna I-40129 (Italy); Sorai, Kazuo [Department of Physics, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Sapporo 060-0810 (Japan)

    2013-03-01

    The nearby low-luminosity active galactic nucleus (LLAGN) NGC 4258 has a weak radio continuum component at the galactic center. We investigate its radio spectral properties on the basis of our new observations using the Nobeyama Millimeter Array at 100 GHz and archival data from the Very Large Array at 1.7-43 GHz and the James Clerk Maxwell telescope at 347 GHz. The NGC 4258 nuclear component exhibits (1) an intra-month variable and complicated spectral feature at 5-22 GHz and (2) a slightly inverted spectrum at 5-100 GHz ({alpha} {approx} 0.3; F {sub {nu}}{proportional_to}{nu}{sup {alpha}}) in time-averaged flux densities, which are also apparent in the closest LLAGN M81. These similarities between NGC 4258 and M81 in radio spectral natures in addition to previously known core shift in their AU-scale jet structures produce evidence that the same mechanism drives their nuclei. We interpret the observed spectral property as the superposition of emission spectra originating at different locations with frequency-dependent opacity along the nuclear jet. Quantitative differences between NGC 4258 and M81 in terms of jet/counter jet ratio, radio loudness, and degree of core shift can be consistently understood by fairly relativistic speeds ({Gamma} {approx}> 3) of jets and their quite different inclinations. The picture established from the two closest LLAGNs is useful for understanding the physical origin of unresolved and flat/inverted spectrum radio cores that are prevalently found in LLAGNs, including Sgr A*, with starved supermassive black holes in the present-day universe.

  15. THE SECOND CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE

    International Nuclear Information System (INIS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bottacini, E.; Antolini, E.; Bonamente, E.; Atwood, W. B.; Bouvier, A.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Barbiellini, G.; Bastieri, D.

    2011-01-01

    The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The second LAT AGN catalog (2LAC) includes 1017 γ-ray sources located at high Galactic latitudes (|b| > 10°) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs. However, some of these are affected by analysis issues and some are associated with multiple AGNs. Consequently, we define a Clean Sample which includes 886 AGNs, comprising 395 BL Lacertae objects (BL Lac objects), 310 flat-spectrum radio quasars (FSRQs), 157 candidate blazars of unknown type (i.e., with broadband blazar characteristics but with no optical spectral measurement yet), 8 misaligned AGNs, 4 narrow-line Seyfert 1 (NLS1s), 10 AGNs of other types, and 2 starburst galaxies. Where possible, the blazars have been further classified based on their spectral energy distributions (SEDs) as archival radio, optical, and X-ray data permit. While almost all FSRQs have a synchrotron-peak frequency 14 Hz, about half of the BL Lac objects have a synchrotron-peak frequency >10 15 Hz. The 2LAC represents a significant improvement relative to the first LAT AGN catalog (1LAC), with 52% more associated sources. The full characterization of the newly detected sources will require more broadband data. Various properties, such as γ-ray fluxes and photon power-law spectral indices, redshifts, γ-ray luminosities, variability, and archival radio luminosities and their correlations are presented and discussed for the different blazar classes. The general trends observed in 1LAC are confirmed.

  16. STAR FORMATION IN SELF-GRAVITATING DISKS IN ACTIVE GALACTIC NUCLEI. II. EPISODIC FORMATION OF BROAD-LINE REGIONS

    International Nuclear Information System (INIS)

    WangJianmin; Du Pu; Ge Junqiang; Hu Chen; Baldwin, Jack A.; Ferland, Gary J.

    2012-01-01

    This is the second in a series of papers discussing the process and effects of star formation in the self-gravitating disk around the supermassive black holes in active galactic nuclei (AGNs). We have previously suggested that warm skins are formed above the star-forming (SF) disk through the diffusion of warm gas driven by supernova explosions. Here we study the evolution of the warm skins when they are exposed to the powerful radiation from the inner part of the accretion disk. The skins initially are heated to the Compton temperature, forming a Compton atmosphere (CAS) whose subsequent evolution is divided into four phases. Phase I is the duration of pure accumulation supplied by the SF disk. During phase II clouds begin to form due to line cooling and sink to the SF disk. Phase III is a period of preventing clouds from sinking to the SF disk through dynamic interaction between clouds and the CAS because of the CAS overdensity driven by continuous injection of warm gas from the SF disk. Finally, phase IV is an inevitable collapse of the entire CAS through line cooling. This CAS evolution drives the episodic appearance of broad-line regions (BLRs). We follow the formation of cold clouds through the thermal instability of the CAS during phases II and III, using linear analysis. Since the clouds are produced inside the CAS, the initial spatial distribution of newly formed clouds and angular momentum naturally follow the CAS dynamics, producing a flattened disk of clouds. The number of clouds in phases II and III can be estimated, as well as the filling factor of clouds in the BLR. Since the cooling function depends on the metallicity, the metallicity gradients that originate in the SF disk give rise to different properties of clouds in different radial regions. We find from the instability analysis that clouds have column density N H ∼ 22 cm –2 in the metal-rich regions whereas they have N H ∼> 10 22 cm –2 in the metal-poor regions. The metal-rich clouds

  17. Accentuated hyperparathyroidism in type II Bartter syndrome.

    Science.gov (United States)

    Landau, Daniel; Gurevich, Evgenia; Sinai-Treiman, Levana; Shalev, Hannah

    2016-07-01

    Bartter syndrome (BS) may be associated with different degrees of hypercalciuria, but marked parathyroid hormone (PTH) abnormalities have not been described. We compared clinical and laboratory data of patients with either ROMK-deficient type II BS (n = 14) or Barttin-deficient type IV BS (n = 20). Only BS-IV patients remained mildly hypokalemic in spite of a higher need for potassium supplementation. Estimated glomerular filtration rate (eGFR) was mildly decreased in only four BS-IV patients. Average PTH values were significantly higher in BS-II (160.6 ± 85.8 vs. 92.5 ± 48 pg/ml in BS-IV, p = 0.006). In both groups, there was a positive correlation between age and log(PTH). Levels of 25(OH) vitamin D were not different. Total serum calcium was lower (within normal limits) and age-related serum phosphate (Pi)-SDS was increased in BS-II (1.19 ± 0.71 vs. 0.01 ± 1.04 in BS-IV, p < 0.001). The GFR threshold for Pi reabsorption was higher in BS-II (5.63 ± 1.25 vs. 4.36 ± 0.98, p = 0.002). Spot urine calcium/creatinine ratio and nephrocalcinosis rate (100 vs. 16 %) were higher in the BS-II group. PTH, serum Pi levels, and urinary threshold for Pi reabsorption are significantly elevated in type II vs. type IV BS, suggesting a PTH resistance state. This may be a response to more severe long-standing hypercalciuria, leading to a higher rate of nephrocalcinosis in BS-II.

  18. Infrared Selection of Obscured Active Galactic Nuclei in the COSMOS Field

    Science.gov (United States)

    Chang, Yu-Yen; Le Floc'h, Emeric; Juneau, Stéphanie; da Cunha, Elisabete; Salvato, Mara; Civano, Francesca; Marchesi, Stefano; Ilbert, Olivier; Toba, Yoshiki; Lim, Chen-Fatt; Tang, Ji-Jia; Wang, Wei-Hao; Ferraro, Nicholas; Urry, Megan C.; Griffiths, Richard E.; Kartaltepe, Jeyhan S.

    2017-12-01

    We present a study of the connection among black hole accretion, star formation, and galaxy morphology at z≤slant 2.5. We focus on active galactic nuclei (AGNs) selected by their mid-IR power-law emission. By fitting optical to far-IR photometry with state-of-the-art spectral energy distribution (SED) techniques, we derive stellar masses, star formation rates, dust properties, and AGN contributions in galaxies over the whole COSMOS field. We find that obscured AGNs lie within or slightly above the star-forming sequence. We confirm our previous finding about compact host galaxies of obscured AGNs at z˜ 1, and find that galaxies with 20%-50% AGN contributions tend to have smaller sizes, by ˜25%-50%, compared to galaxies without AGNs. Furthermore, we find that a high merger fraction of up to 0.5 is appropriate for the most luminous ({log}({L}{IR}/{L}⊙ )˜ 12.5) AGN hosts and non-AGN galaxies, but not for the whole obscured AGN sample. Moreover, the merger fraction depends on the total and star-forming IR luminosity, rather than on the decomposed AGN infrared luminosity. Our results suggest that major mergers are not the main driver of AGN activity, and therefore obscured AGNs might be triggered by internal mechanisms, such as secular processes, disk instabilities, and compaction in a particular evolutionary stage. We make the SED modeling results publicly available.

  19. ON THE HOST GALAXY OF GRB 150101B AND THE ASSOCIATED ACTIVE GALACTIC NUCLEUS

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Chen [Department of Physics, Xiamen University, Xiamen (China); Fang, Taotao; Wang, Junfeng; Liu, Tong; Jiang, Xiaochuan, E-mail: fangt@xmu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen (China)

    2016-06-20

    We present a multi-wavelength analysis of the host galaxy of short-duration gamma-ray burst (GRB) 150101B. Follow-up optical and X-ray observations suggested that the host galaxy, 2MASX J12320498-1056010, likely harbors low-luminosity active galactic nuclei (AGNs). Our modeling of the spectral energy distribution has confirmed the nature of the AGN, making it the first reported GRB host that contains an AGN. We have also found the host galaxy is a massive elliptical galaxy with stellar population of ∼5.7 Gyr, one of the oldest among the short-duration GRB hosts. Our analysis suggests that the host galaxy can be classified as an X-ray bright, optically normal galaxy, and the central AGN is likely dominated by a radiatively inefficient accretion flow. Our work explores an interesting connection that may exist between GRB and AGN activities of the host galaxy, which can help in understanding the host environment of the GRB events and the roles of AGN feedback.

  20. Galaxy And Mass Assembly (GAMA): the effect of galaxy group environment on active galactic nuclei

    Science.gov (United States)

    Gordon, Yjan A.; Pimbblet, Kevin A.; Owers, Matt S.; Bland-Hawthorn, Joss; Brough, Sarah; Brown, Michael J. I.; Cluver, Michelle E.; Croom, Scott M.; Holwerda, Benne W.; Loveday, Jonathan; Mahajan, Smriti; Wang, Lingyu

    2018-04-01

    In galaxy clusters, efficiently accreting active galactic nuclei (AGNs) are preferentially located in the infall regions of the cluster projected phase-space, and are rarely found in the cluster core. This has been attributed to both an increase in triggering opportunities for infalling galaxies, and a reduction of those mechanisms in the hot, virialized, cluster core. Exploiting the depth and completeness (98 per cent at r 9.9 in 695 groups with 11.53 ≤ log10(M200/M⊙) ≤ 14.56 at z 13.5, AGNs are preferentially found in the infalling galaxy population with 3.6σ confidence. At lower halo masses, we observe no difference in AGN fraction between core and infalling galaxies. These observations support a model where a reduced number of low-speed interactions, ram pressure stripping and intra-group/cluster medium temperature, the dominance of which increase with halo mass, work to inhibit AGN in the cores of groups and clusters with log10(M200/M⊙) > 13.5, but do not significantly affect nuclear activity in cores of less massive structures.

  1. ON THE HOST GALAXY OF GRB 150101B AND THE ASSOCIATED ACTIVE GALACTIC NUCLEUS

    International Nuclear Information System (INIS)

    Xie, Chen; Fang, Taotao; Wang, Junfeng; Liu, Tong; Jiang, Xiaochuan

    2016-01-01

    We present a multi-wavelength analysis of the host galaxy of short-duration gamma-ray burst (GRB) 150101B. Follow-up optical and X-ray observations suggested that the host galaxy, 2MASX J12320498-1056010, likely harbors low-luminosity active galactic nuclei (AGNs). Our modeling of the spectral energy distribution has confirmed the nature of the AGN, making it the first reported GRB host that contains an AGN. We have also found the host galaxy is a massive elliptical galaxy with stellar population of ∼5.7 Gyr, one of the oldest among the short-duration GRB hosts. Our analysis suggests that the host galaxy can be classified as an X-ray bright, optically normal galaxy, and the central AGN is likely dominated by a radiatively inefficient accretion flow. Our work explores an interesting connection that may exist between GRB and AGN activities of the host galaxy, which can help in understanding the host environment of the GRB events and the roles of AGN feedback.

  2. HOST GALAXY PROPERTIES OF THE SWIFT BAT ULTRA HARD X-RAY SELECTED ACTIVE GALACTIC NUCLEUS

    International Nuclear Information System (INIS)

    Koss, Michael; Mushotzky, Richard; Veilleux, Sylvain; Winter, Lisa M.; Baumgartner, Wayne; Tueller, Jack; Gehrels, Neil; Valencic, Lynne

    2011-01-01

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) active galactic nucleus (AGN) with host galaxy optical data to date, with 185 nearby (z * >10.5) have a 5-10 times higher rate of spiral morphologies than in SDSS AGNs or inactive galaxies. We also see enhanced far-infrared emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGNs are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line (NL) BAT AGNs have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III] λ5007. There is also a correlation between the stellar mass and X-ray emission. The BAT AGNs in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as a whole. In agreement with the unified model of AGNs, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of obscuration such as X-ray column density or Seyfert type. The high fraction of massive spiral galaxies and galaxy mergers in BAT AGNs suggest that host galaxy morphology is related to the activation and fueling of local AGN.

  3. MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Ichikawa, Kohei; Ueda, Yoshihiro; Terashima, Yuichi; Oyabu, Shinki; Gandhi, Poshak; Nakagawa, Takao; Matsuta, Keiko

    2012-01-01

    We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with Infrared Astronomical Satellite and Wide-field Infrared Survey Explorer. Out of 135 non-blazer AGNs in the Swift/BAT nine-month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 μm band. We find good correlation between their hard X-ray and MIR luminosities over three orders of magnitude (42 λ (9, 18 μm) < 45), which is tighter than that with the FIR luminosities at 90 μm. This suggests that thermal emission from hot dusts irradiated by the AGN emission dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the same correlation, implying isotropic infrared emission, as expected in clumpy dust tori rather than homogeneous ones. We find excess signals around 9 μm in the averaged infrared spectral energy distribution from heavy obscured 'new type' AGNs with small scattering fractions in the X-ray spectra. This could be attributed to the polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.

  4. Impact of red giant/AGB winds on active galactic nucleus jet propagation

    Science.gov (United States)

    Perucho, M.; Bosch-Ramon, V.; Barkov, M. V.

    2017-10-01

    Context. Dense stellar winds may mass-load the jets of active galactic nuclei, although it is unclear on what time and spatial scales the mixing takes place. Aims: Our aim is to study the first steps of the interaction between jets and stellar winds, and also the scales on which the stellar wind mixes with the jet and mass-loads it. Methods: We present a detailed 2D simulation - including thermal cooling - of a bubble formed by the wind of a star designed to study the initial stages of jet-star interaction. We also study the first interaction of the wind bubble with the jet using a 3D simulation in which the star enters the jet. Stability analysis is carried out for the shocked wind structure to evaluate the distances over which the jet-dragged wind, which forms a tail, can propagate without mixing with the jet flow. Results.The 2D simulations point to quick wind bubble expansion and fragmentation after about one bubble shock crossing time. Three-dimensional simulations and stability analysis point to local mixing in the case of strong perturbations and relatively low density ratios between the jet and the jet dragged-wind, and to a possibly more stable shocked wind structure at the phase of maximum tail mass flux. Analytical estimates also indicate that very early stages of the star jet-penetration time may be also relevant for mass-loading. The combination of these and previous results from the literature suggests highly unstable interaction structures and efficient wind-jet flow mixing on the scale of the jet interaction height. Conclusions: The winds of stars with strong mass loss can efficiently mix with jets from active galactic nuclei. In addition, the initial wind bubble shocked by the jet leads to a transient, large interaction surface. The interaction between jets and stars can produce strong inhomogeneities within the jet. As mixing is expected to be effective on large scales, even individual asymptotic giant branch stars can significantly contribute to

  5. Recognition of lysophosphatidylcholine by type II NKT cells and protection from an inflammatory liver disease.

    Science.gov (United States)

    Maricic, Igor; Girardi, Enrico; Zajonc, Dirk M; Kumar, Vipin

    2014-11-01

    Lipids presented by the MHC class I-like molecule, CD1d, are recognized by NK T (NKT) cells, which can be broadly categorized into two subsets. The well-characterized type I NKT cells express a semi-invariant TCR and can recognize both α- and β-linked glycolipids, whereas type II NKT cells are less well studied, express a relatively diverse TCR repertoire, and recognize β-linked lipids. Recent structural studies have shown a distinct mode of recognition of a self-glycolipid sulfatide bound to CD1d by a type II NKT TCR. To further characterize Ag recognition by these cells, we have used the structural data and screened other small molecules able to bind to CD1d and activate type II NKT cells. Using plate-bound CD1d and APC-based Ag presentation assay, we found that phospholipids such as lysophosphatidylcholine (LPC) can stimulate the sulfatide-reactive type II NKT hybridoma Hy19.3 in a CD1d-dependent manner. Using plasmon resonance studies, we found that this type II NKT TCR binds with CD1d-bound LPC with micromolar affinities similar to that for sulfatide. Furthermore, LPC-mediated activation of type II NKT cells leads to anergy induction in type I NKT cells and affords protection from Con A-induced hepatitis. These data indicate that, in addition to self-glycolipids, self-lysophospholipids are also recognized by type II NKT cells. Because lysophospholipids are involved during inflammation, our findings have implications for not only understanding activation of type II NKT cells in physiological settings, but also for the development of immune intervention in inflammatory diseases. Copyright © 2014 by The American Association of Immunologists, Inc.

  6. ON THE 10 μm SILICATE FEATURE IN ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Nikutta, Robert; Elitzur, Moshe; Lacy, Mark

    2009-01-01

    The 10 μm silicate feature observed with Spitzer in active galactic nuclei (AGNs) reveals some puzzling behavior. It (1) has been detected in emission in type 2 sources, (2) shows broad, flat-topped emission peaks shifted toward long wavelengths in several type 1 sources, and (3) is not seen in deep absorption in any source observed so far. We solve all three puzzles with our clumpy dust radiative transfer formalism. Addressing (1), we present the spectral energy distribution (SED) of SST1721+6012, the first type 2 quasar observed to show a clear 10 μm silicate feature in emission. Such emission arises in models of the AGN torus easily when its clumpy nature is taken into account. We constructed a large database of clumpy torus models and performed extensive fitting of the observed SED. We find that the cloud radial distribution varies as r -1.5 and the torus contains 2-4 clouds along radial equatorial rays, each with optical depth at visual ∼60-80. The source bolometric luminosity is ∼3 x 10 12 L sun . Our modeling suggests that ∼<35% of objects with tori sharing these characteristics and geometry would have their central engines obscured. This relatively low obscuration probability can explain the clear appearance of the 10 μm emission feature in SST1721+6012 together with its rarity among other QSO2. Investigating (2), we also fitted the SED of PG1211+143, one of the first type 1 QSOs with a 10 μm silicate feature detected in emission. Together with other similar sources, this QSO appears to display an unusually broadened feature whose peak is shifted toward longer wavelengths. Although this led to suggestions of non-standard dust chemistry in these sources, our analysis fits such SEDs with standard galactic dust; the apparent peak shifts arise from simple radiative transfer effects. Regarding (3), we find additionally that the distribution of silicate feature strengths among clumpy torus models closely resembles the observed distribution, and the

  7. On the 10 μm Silicate Feature in Active Galactic Nuclei

    Science.gov (United States)

    Nikutta, Robert; Elitzur, Moshe; Lacy, Mark

    2009-12-01

    The 10 μm silicate feature observed with Spitzer in active galactic nuclei (AGNs) reveals some puzzling behavior. It (1) has been detected in emission in type 2 sources, (2) shows broad, flat-topped emission peaks shifted toward long wavelengths in several type 1 sources, and (3) is not seen in deep absorption in any source observed so far. We solve all three puzzles with our clumpy dust radiative transfer formalism. Addressing (1), we present the spectral energy distribution (SED) of SST1721+6012, the first type 2 quasar observed to show a clear 10 μm silicate feature in emission. Such emission arises in models of the AGN torus easily when its clumpy nature is taken into account. We constructed a large database of clumpy torus models and performed extensive fitting of the observed SED. We find that the cloud radial distribution varies as r -1.5 and the torus contains 2-4 clouds along radial equatorial rays, each with optical depth at visual ~60-80. The source bolometric luminosity is ~3 × 1012 Lsun. Our modeling suggests that lsim35% of objects with tori sharing these characteristics and geometry would have their central engines obscured. This relatively low obscuration probability can explain the clear appearance of the 10 μm emission feature in SST1721+6012 together with its rarity among other QSO2. Investigating (2), we also fitted the SED of PG1211+143, one of the first type 1 QSOs with a 10 μm silicate feature detected in emission. Together with other similar sources, this QSO appears to display an unusually broadened feature whose peak is shifted toward longer wavelengths. Although this led to suggestions of non-standard dust chemistry in these sources, our analysis fits such SEDs with standard galactic dust; the apparent peak shifts arise from simple radiative transfer effects. Regarding (3), we find additionally that the distribution of silicate feature strengths among clumpy torus models closely resembles the observed distribution, and the feature

  8. Active galactic nucleus black hole mass estimates in the era of time domain astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Brandon C.; Treu, Tommaso; Pancoast, Anna [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106-9530 (United States); Malkan, Matthew [Department of Astronomy, 430 Portola Plaza, Box 951547, University of California, Los Angeles, CA 90095-1547 (United States); Woo, Jong-Hak [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2013-12-20

    We investigate the dependence of the normalization of the high-frequency part of the X-ray and optical power spectral densities (PSDs) on black hole mass for a sample of 39 active galactic nuclei (AGNs) with black hole masses estimated from reverberation mapping or dynamical modeling. We obtained new Swift observations of PG 1426+015, which has the largest estimated black hole mass of the AGNs in our sample. We develop a novel statistical method to estimate the PSD from a light curve of photon counts with arbitrary sampling, eliminating the need to bin a light curve to achieve Gaussian statistics, and we use this technique to estimate the X-ray variability parameters for the faint AGNs in our sample. We find that the normalization of the high-frequency X-ray PSD is inversely proportional to black hole mass. We discuss how to use this scaling relationship to obtain black hole mass estimates from the short timescale X-ray variability amplitude with precision ∼0.38 dex. The amplitude of optical variability on timescales of days is also anticorrelated with black hole mass, but with larger scatter. Instead, the optical variability amplitude exhibits the strongest anticorrelation with luminosity. We conclude with a discussion of the implications of our results for estimating black hole mass from the amplitude of AGN variability.

  9. THE SUBARCSECOND MID-INFRARED VIEW OF LOCAL ACTIVE GALACTIC NUCLEI. III. POLAR DUST EMISSION

    International Nuclear Information System (INIS)

    Asmus, D.; Hönig, S. F.; Gandhi, P.

    2016-01-01

    Recent mid-infrared (MIR) interferometric observations have shown that in a few active galactic nuclei (AGNs) the bulk of the infrared emission originates from the polar region above the putative torus, where only a little dust should be present. Here, we investigate whether such strong polar dust emission is common in AGNs. Out of 149 Seyferts in the MIR atlas of local AGNs, 21 show extended MIR emission on single-dish images. In 18 objects, the extended MIR emission aligns with the position angle (PA) of the system axis, established by [O iii], radio, polarization, and maser-based PA measurements. The relative amount of resolved MIR emission is at least 40% and scales with the [O iv] fluxes, implying a strong connection between the extended continuum and [O iv] emitters. These results together with the radio-quiet nature of the Seyferts support the scenario that the bulk of MIR emission is emitted by dust in the polar region and not by the torus, which would demand a new paradigm for the infrared emission structure in AGNs. The current low detection rate of polar dust in the AGNs of the MIR atlas is explained by the lack of sufficient high-quality MIR data and the requirements on the orientation, strength of narrow-line region, and distance of the AGNs. The James Webb Space Telescope will enable much deeper nuclear MIR studies with comparable angular resolution, allowing us to resolve the polar emission and surroundings in most of the nearby AGNs.

  10. X-ray spectra and time variability of active galactic nuclei

    International Nuclear Information System (INIS)

    Mushotzky, R.F.

    1984-02-01

    The X-ray spectra of broad line active galactic nuclei (AGN) of all types (Seyfert I's, NELG's, broadline radio galaxies) are well fit by a power law in the .5 to 100 keV band of man energy slope alpha .68 + or - .15. There is, as yet, no strong evidence for time variability of this slope in a given object. The constraints that this places on simple models of the central energy source are discussed. BL Lac objects have quite different X-ray spectral properties and show pronounced X-ray spectral variability. On time scales longer than 12 hours most radio quiet AGN do not show strong, delta I/I .5, variability. The probability of variability of these AGN seems to be inversely related to their luminosity. However characteristics timescales for variability have not been measured for many objects. This general lack of variability may imply that most AGN are well below the Eddington limit. Radio bright AGN tend to be more variable than radio quiet AGN on long, tau approx 6 month, timescales

  11. THE EVOLUTION OF ACTIVE GALACTIC NUCLEI IN CLUSTERS OF GALAXIES TO REDSHIFT 1.3

    International Nuclear Information System (INIS)

    Martini, Paul; Sivakoff, Gregory R.; Mulchaey, John S.

    2009-01-01

    We have measured the luminous active galactic nucleus (AGN) population in a large sample of clusters of galaxies and find evidence for a substantial increase in the cluster AGN population from z ∼ 0.05 to z ∼ 1.3. The present sample now includes 32 clusters of galaxies, including 15 clusters above z = 0.4, which corresponds to a three-fold increase compared to our previous work at high redshift. At z R R (z) + 1 that host AGNs with rest-frame, hard X-ray [2-10 keV] luminosities L X,H ≥ 10 43 erg s -1 . The AGN fraction increases from f A = 0.134 +0.18 -0.087 % at a median z = 0.19 to f A = 1.00 +0.29 -0.23 % at a median z = 0.72. Our best estimate of the evolution is a factor of 8 increase to z = 1 and the statistical significance of the increase is 3.8σ. This dramatic evolution is qualitatively similar to the evolution of the star-forming galaxy population in clusters known as the Butcher-Oemler effect. We discuss the implications of this result for the coevolution of black holes and galaxies in clusters, the evolution of AGN feedback, searches for clusters with the Sunyaev-Zel'dovich effect, and the possible detection of environment-dependent downsizing.

  12. RESOLVING THE GEOMETRY OF THE INNERMOST RELATIVISTIC JETS IN ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Algaba, J. C.; Lee, S. S. [Korea Astronomy and Space Science Institute, 776, Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of); Nakamura, M.; Asada, K., E-mail: algaba@kasi.re.kr [Academia Sinica, Institute of Astronomy and Astrophysics, 11F of Astronomy-Mathematics Building, AS/NTU. No.1, Section 4, Roosevelt Road, Taipei 10617, Taiwan, R.O.C (China)

    2017-01-01

    In the current paradigm, it is believed that the compact VLBI radio core of radio-loud active galactic nuclei (AGNs) represents the innermost upstream regions of relativistic outflows. These regions of AGN jets have generally been modeled by a conical outflow with a roughly constant opening angle and flow speed. Nonetheless, some works suggest that a parabolic geometry would be more appropriate to fit the high energy spectral distribution properties and it has been recently found that, at least in some nearby radio galaxies, the geometry of the innermost regions of the jet is parabolic. We compile here multi-frequency core sizes of archival data to investigate the typically unresolved upstream regions of the jet geometry of a sample of 56 radio-loud AGNs. Data combined from the sources considered here are not consistent with the classic picture of a conical jet starting in the vicinity of the super-massive black hole (SMBH), and may exclude a pure parabolic outflow solution, but rather suggest an intermediate solution with quasi-parabolic streams, which are frequently seen in numerical simulations. Inspection of the large opening angles near the SMBH and the range of the Lorentz factors derived from our results support our analyses. Our result suggests that the conical jet paradigm in AGNs needs to be re-examined by millimeter/sub-millimeter VLBI observations.

  13. Investigating the variability of active galactic nuclei using combined multi-quarter Kepler data

    Energy Technology Data Exchange (ETDEWEB)

    Revalski, Mitchell; Nowak, Dawid; Wiita, Paul J. [Department of Physics, The College of New Jersey, P.O. Box 7718, Ewing, NJ 08628 (United States); Wehrle, Ann E. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Unwin, Stephen C., E-mail: revalsm1@tcnj.edu [Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 321-100, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2014-04-10

    We used photometry from the Kepler satellite to characterize the variability of four radio-loud active galactic nuclei (AGNs) on timescales from years to minutes. The Kepler satellite produced nearly continuous high precision data sets which provided better temporal coverage than possible with ground based observations. We have now accumulated 11 quarters of data, eight of which were reported in our previous paper. In addition to constructing power spectral densities (PSDs) and characterizing the variability of the last three quarters, we have linked together the individual quarters using a multiplicative scaling process, providing data sets spanning ∼2.8 yr with >98% coverage at a 30 minute sampling rate. We compute PSDs on these connected data sets that yield power law slopes at low frequencies in the approximate range of –1.5 to –2.0, with white noise seen at higher frequencies. These PSDs are similar to those of both the individual quarters and to those of ground-based optical observations of other AGNs. We also have explored a PSD binning method intended to reduce a bias toward shallow slope fits by evenly distributing the points within the PSDs. This tends to steepen the computed PSD slopes, especially when the low frequencies are relatively poorly fit. We detected flares lasting several days in which the brightness increased by ∼15%-20% in one object, as well a smaller flare in another. Two AGNs showed only small, ∼1%-2%, fluctuations in brightness.

  14. An Iwasawa-Taniguchi Effect for Compton-thick Active Galactic Nuclei

    Science.gov (United States)

    Boorman, Peter G.; Gandhi, Poshak; Baloković, Mislav; Brightman, Murray; Harrison, Fiona; Ricci, Claudio; Stern, Daniel

    2018-04-01

    We present the first study of an Iwasawa-Taniguchi/`X-ray Baldwin' effect for Compton-thick active galactic nuclei (AGN). We report a statistically significant anti-correlation between the rest-frame equivalent width (EW) of the narrow core of the neutral Fe Kα fluorescence emission line, ubiquitously observed in the reflection spectra of obscured AGN, and the mid-infrared 12 μ m continuum luminosity (taken as a proxy for the bolometric AGN luminosity). Our sample consists of 72 Compton-thick AGN selected from pointed and deep-field observations covering a redshift range of z ˜ 0.0014 - 3.7. We employ a Monte Carlo-based fitting method, which returns a Spearman's Rank correlation coefficient of ρ = - 0.28 ± 0.12, significant to 98.7% confidence. The best fit found is log(EW_{Fe Kα }) ∝ -0.08± 0.04 log(L_{12 {μ } m}), which is consistent with multiple studies of the X-ray Baldwin effect for unobscured and mildly obscured AGN. This is an unexpected result, as the Fe Kα line is conventionally thought to originate from the same region as the underlying reflection continuum, which together constitute the reflection spectrum. We discuss the implications this could have if confirmed on larger samples, including a systematic underestimation of the line of sight X-ray obscuring column density and hence the intrinsic luminosities and growth rates for the most luminous AGN.

  15. A Catalog of Active Galactic Nuclei from the First 1.5 Gyr of the Universe

    Energy Technology Data Exchange (ETDEWEB)

    Perger, Krisztina [Department of Astronomy, Eötvös Loránd University, Budapest (Hungary); Frey, Sándor; Gabányi, Krisztina É. [Konkoly Observatory, MTA Research Centre for Astronomy and Earth Sciences, Budapest (Hungary); Tóth, L. Viktor, E-mail: k.perger@astro.elte.hu [Department of Astronomy, Eötvös Loránd University, Budapest (Hungary)

    2017-08-08

    Active galactic nuclei (AGN) are prominent astrophysical objects that can be observed throughout the whole Universe. To understand the underlying physical processes and the different appearance of AGN types, extensive samples are needed. Nowadays, various AGN catalogs are available at different wavebands. However, at the highest redshifts data are still relatively sparse. These data are required for examining AGN properties in the early Universe. This way we can compare the earliest AGN with those seen at lower redshifts, and can study their cosmological evolution. Additionally, because of their high luminosity, AGN may also be used as probes to test cosmological models. With the aim of constructing a complete sample of all known AGN at z ≥ 4, we are currently compiling a photometric catalog from literature sources. We cross-match catalogs particularly at optical and radio wavebands, to build up a sample for detailed high-resolution radio interferometric studies. The continuously updated list now contains nearly 2,600 objects with known spectroscopic redshifts, optical magnitudes, and auxiliary information about observations at other wavebands. About 170 of them are known radio sources for which we collect existing radio interferometric data from the literature.

  16. THE MERGER-TRIGGERED ACTIVE GALACTIC NUCLEUS CONTRIBUTION TO THE ULTRALUMINOUS INFRARED GALAXY POPULATION

    International Nuclear Information System (INIS)

    Draper, A. R.; Ballantyne, D. R.

    2012-01-01

    It has long been thought that there is a connection between ultraluminous infrared galaxies (ULIRGs), quasars, and major mergers. Indeed, simulations show that major mergers are capable of triggering massive starbursts and quasars. However, observations by the Herschel Space Observatory suggest that, at least at high redshift, there may not always be a simple causal connection between ULIRGs and mergers. Here, we combine an evolving merger-triggered active galactic nucleus (AGN) luminosity function with a merger-triggered starburst model to calculate the maximum contribution of major mergers to the ULIRG population. We find that major mergers can account for the entire local population of ULIRGs hosting AGNs and ∼25% of the total local ULIRG luminosity density. By z ∼ 1, major mergers can no longer account for the luminosity density of ULIRGs hosting AGNs and contribute ∼<12% of the total ULIRG luminosity density. This drop is likely due to high-redshift galaxies being more gas rich and therefore able to achieve high star formation rates through secular evolution. Additionally, we find that major mergers can account for the local population of warm ULIRGs. This suggests that selecting high-redshift warm ULIRGs will allow for the identification of high-redshift merger-triggered ULIRGs. As major mergers are likely to trigger very highly obscured AGNs, a significant fraction of the high-redshift warm ULIRG population may host Compton thick AGNs.

  17. The origin of the mid-infrared nuclear polarization of active galactic nuclei

    Science.gov (United States)

    Lopez-Rodriguez, E.; Alonso-Herrero, A.; Diaz-Santos, T.; Gonzalez-Martin, O.; Ichikawa, K.; Levenson, N. A.; Martinez-Paredes, M.; Nikutta, R.; Packham, C.; Perlman, E.; Almeida, C. Ramos; Rodriguez-Espinosa, J. M.; Telesco, C. M.

    2018-05-01

    We combine new (NGC 1275, NGC 4151, and NGC 5506) and previously published (Cygnus A, Mrk 231, and NGC 1068) sub-arcsecond resolution mid-infrared (MIR; 8-13 μm) imaging- and spectro-polarimetric observations of six Seyfert galaxies using CanariCam on the 10.4-m Gran Telescopio CANARIAS. These observations reveal a diverse set of physical processes responsible for the nuclear polarization, and permit characterization of the origin of the MIR nuclear polarimetric signature of active galactic nuclei (AGN). For all radio quiet objects, we found that the nuclear polarization is low (sensitivity to detect such extended emission (i.e., NGC 1068 and NGC 4151). We suggest that the higher degree of polarization previously found in lower resolution data arises only on the larger-than-nuclear scales. Only the radio-loud Cygnus A exhibits significant nuclear polarization (˜11 per cent), attributable to synchrotron emission from the pc-scale jet close to the core. We present polarization models that suggest that the MIR nuclear polarization for highly obscured objects arises from a self-absorbed MIR polarized clumpy torus and/or dichroism from the host galaxy, while for unabsorbed cores, MIR polarization arises from dust scattering in the torus and/or surrounding nuclear dust.

  18. From molecular clouds to active galactic nuclei - The universality of the jet phenomenon

    International Nuclear Information System (INIS)

    Konigl, A.

    1986-01-01

    Jets are among the most remarkable astrophysical phenomena explored in recent years. The term ''jets'' was originally coined to describe the narrow, elongated features that had been discovered in radio maps (and, in some cases, also by X-ray and optical observations) of extragalactic sources. Similar features have subsequently been found, however, also in our own galaxy, with the relativistic beams of SS433 being probably the most celebrated example. While the SS433 beams are still unique, there is now mounting evidence that oppositely directed jets are very frequently associated with nascent stars embedded in dense molecular clouds. The purpose of this article is, in essence, to ''bridge the gap'' between these smallest-scale jets and their enormously larger extragalactic counterparts. By concentrating on the similarities between molecular-cloud and extragalactic jets, the author shall try to extract some of the basic dynamical principles that could account for the apparent universality of this phenomenon. Following an observational overview, he considers the general hydrodynamic and magnetohydrodynamic (MHD) aspects of the production, the collimation, and the propagation of jets in protostellar and in active-galactic-nuclei (AGN) environments

  19. A MULTI-WAVELENGTH ANALYSIS OF NGC 4178: A BULGELESS GALAXY WITH AN ACTIVE GALACTIC NUCLEUS

    International Nuclear Information System (INIS)

    Secrest, N. J.; Satyapal, S.; Gliozzi, M.; Moran, S. M.; Cheung, C. C.; Giroletti, M.; Bergmann, M. P.; Seth, A. C.

    2013-01-01

    We present Gemini longslit optical spectroscopy and Very Large Array radio observations of the nuclear region of NGC 4178, a late-type bulgeless disk galaxy recently confirmed to host an active galactic nucleus (AGN) through infrared and X-ray observations. Our observations reveal that the dynamical center of the galaxy is coincident with the location of the Chandra X-ray point source discovered in a previous work, providing further support for the presence of an AGN. While the X-ray and IR observations provide robust evidence for an AGN, the optical spectrum shows no evidence for the AGN, underscoring the need for the penetrative power of mid-IR and X-ray observations in finding buried or weak AGNs in this class of galaxy. Finally, the upper limit to the radio flux, together with our previous X-ray and IR results, is consistent with the scenario in which NGC 4178 harbors a deeply buried AGN accreting at a high rate

  20. A Catalog of Active Galactic Nuclei from the First 1.5 Gyr of the Universe

    Directory of Open Access Journals (Sweden)

    Krisztina Perger

    2017-08-01

    Full Text Available Active galactic nuclei (AGN are prominent astrophysical objects that can be observed throughout the whole Universe. To understand the underlying physical processes and the different appearance of AGN types, extensive samples are needed. Nowadays, various AGN catalogs are available at different wavebands. However, at the highest redshifts data are still relatively sparse. These data are required for examining AGN properties in the early Universe. This way we can compare the earliest AGN with those seen at lower redshifts, and can study their cosmological evolution. Additionally, because of their high luminosity, AGN may also be used as probes to test cosmological models. With the aim of constructing a complete sample of all known AGN at z ≥ 4, we are currently compiling a photometric catalog from literature sources. We cross-match catalogs particularly at optical and radio wavebands, to build up a sample for detailed high-resolution radio interferometric studies. The continuously updated list now contains nearly 2,600 objects with known spectroscopic redshifts, optical magnitudes, and auxiliary information about observations at other wavebands. About 170 of them are known radio sources for which we collect existing radio interferometric data from the literature.

  1. TRACING MULTIPLE GENERATIONS OF ACTIVE GALACTIC NUCLEUS FEEDBACK IN THE CORE OF ABELL 262

    International Nuclear Information System (INIS)

    Clarke, T. E.; Kassim, N. E.; Blanton, E. L.; Anderson, L. D.; Douglass, E. M.; Sarazin, C. L.; Gopal-Krishna

    2009-01-01

    We present new radio and X-ray observations of Abell 262. The X-ray residual image provides the first evidence of an X-ray tunnel in this system while the radio data reveal that the central radio source is more than three times larger than previously known. We find that the well-known cluster-center S-shaped radio source B2 0149+35 is surrounded by extended emission to the east and southwest. The south-western extension is cospatial with the X-ray tunnel seen in our new Chandra images while the eastern extension shows three clumps of emission with the innermost coincident with a faint X-ray cavity. The outer two eastern radio extensions are coincident with a newly detected X-ray depression. We use the projected separation of the emission regions to estimate a lower limit of τ rep = 28 Myr to the outburst repetition timescale of the central active galactic nucleus (AGN). The total energy input into the cluster over multiple outburst episodes is estimated to be 2.2 x 10 58 erg, more than an order of magnitude larger than previously thought. The total AGN energy output determined from our new observations shows that the source should be capable of offsetting radiative cooling over several outburst episodes.

  2. Geometrically Thick Obscuration by Radiation-driven Outflow from Magnetized Tori of Active Galactic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Chi-Ho [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Krolik, Julian H. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2017-07-01

    Near-Eddington radiation from active galactic nuclei (AGNs) has significant dynamical influence on the surrounding dusty gas, plausibly furnishing AGNs with geometrically thick obscuration. We investigate this paradigm with radiative magnetohydrodynamics simulations. The simulations solve the magnetohydrodynamics equations simultaneously with the infrared (IR) and ultraviolet (UV) radiative transfer (RT) equations; no approximate closure is used for RT. We find that our torus, when given a suitable sub-Keplerian angular momentum profile, spontaneously evolves toward a state in which its opening angle, density distribution, and flow pattern change only slowly. This “steady” state lasts for as long as there is gas resupply toward the inner edge. The torus is best described as a midplane inflow and a high-latitude outflow. The outflow is launched from the torus inner edge by UV radiation and expands in solid angle as it ascends; IR radiation continues to drive the wide-angle outflow outside the central hole. The dusty outflow obscures the central source in soft X-rays, the IR, and the UV over three-quarters of solid angle, and each decade in column density covers roughly equal solid angle around the central source; these obscuration properties are similar to what observations imply.

  3. A near-infrared relationship for estimating black hole masses in active galactic nuclei

    Science.gov (United States)

    Landt, Hermine; Ward, Martin J.; Peterson, Bradley M.; Bentz, Misty C.; Elvis, Martin; Korista, Kirk T.; Karovska, Margarita

    2013-06-01

    Black hole masses for samples of active galactic nuclei (AGN) are currently estimated from single-epoch optical spectra using scaling relations anchored in reverberation mapping results. In particular, the two quantities needed for calculating black hole masses, namely the velocity and the radial distance of the orbiting gas are derived from the widths of the Balmer hydrogen broad emission lines and the optical continuum luminosity, respectively. We have recently presented a near-infrared (near-IR) relationship for estimating AGN black hole masses based on the widths of the Paschen hydrogen broad emission lines and the total 1 μm continuum luminosity. The near-IR offers several advantages over the optical: it suffers less from dust extinction, the AGN continuum is observed only weakly contaminated by the host galaxy and the strongest Paschen broad emission lines Paα and Paβ are unblended. Here, we improve the calibration of the near-IR black hole mass relationship by increasing the sample from 14 to 23 reverberation-mapped AGN using additional spectroscopy obtained with the Gemini Near-Infrared Spectrograph. The additional sample improves the number statistics in particular at the high-luminosity end.

  4. The near-infrared radius-luminosity relationship for active galactic nuclei

    Science.gov (United States)

    Landt, Hermine; Bentz, Misty C.; Peterson, Bradley M.; Elvis, Martin; Ward, Martin J.; Korista, Kirk T.; Karovska, Margarita

    2011-05-01

    Black hole masses for samples of active galactic nuclei (AGNs) are currently estimated from single-epoch optical spectra. In particular, the size of the broad-line emitting region needed to compute the black hole mass is derived from the optical or ultraviolet continuum luminosity. Here we consider the relationship between the broad-line region size, R, and the near-infrared (near-IR) AGN continuum luminosity, L, as the near-IR continuum suffers less dust extinction than at shorter wavelengths and the prospects for separating the AGN continuum from host-galaxy starlight are better in the near-IR than in the optical. For a relationship of the form R∝Lα, we obtain for a sample of 14 reverberation-mapped AGN a best-fitting slope of α= 0.5 ± 0.1, which is consistent with the slope of the relationship in the optical band and with the value of 0.5 naïvely expected from photoionization theory. Black hole masses can then be estimated from the near-IR virial product, which is calculated using the strong and unblended Paschen broad emission lines (Paα or Paβ).

  5. Constraints on the outer radius of the broad emission line region of active galactic nuclei

    Science.gov (United States)

    Landt, Hermine; Ward, Martin J.; Elvis, Martin; Karovska, Margarita

    2014-03-01

    Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Paα and Paβ, and find that it scales with the ionizing continuum luminosity roughly as expected from photoionization theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution in orbital motion and an accretion disc wind if the ratio between the BELR outer and inner radius is assumed to be less than ˜100-200. On the other hand, a pure Keplerian disc can be largely excluded, since for most orientations and radial extents of the disc the emission line profile is double-horned.

  6. Probing the Large Faraday Rotation Measure Environment of Compact Active Galactic Nuclei

    Directory of Open Access Journals (Sweden)

    Alice Pasetto

    2018-03-01

    Full Text Available Knowing how the ambient medium in the vicinity of active galactic nuclei (AGNs is shaped is crucial to understanding generally the evolution of such cosmic giants as well as AGN jet formation and launching. Thanks to the new broadband capability now available at the Jansky Very Large Array (JVLA, we can study changes in polarization properties, fractional polarization, and polarization angles, together with the total intensity spectra of a sample of 14 AGNs, within a frequency range from 1 to 12 GHz. Depolarization modeling has been performed by means of so-called “qu-fitting” to the polarized data, and a synchrotron self absorption model has been used for fitting to the total intensity data. We found complex behavior both in the polarization spectra and in the total intensity spectra, and several Faraday components with a large rotation measure (RM and several synchrotron components were needed to represent these spectra. Here, results for three targets are shown. This new method of analyzing broadband polarization data through qu-fitting successfully maps the complex surroundings of unresolved objects.

  7. Effects of thermal plasma on self-absorbed synchrotron sources in active galactic nuclei

    International Nuclear Information System (INIS)

    De Kool, M.; Begelman, M.C.

    1989-01-01

    The observable effects of a thermal background plasma in a self-absorbed synchrotron source are reviewed, in the context of a model for the central engine of an active galactic nucleus (AGN). Considering the effects of free-free absorption and emission, Thomson and Compton scattering, and spatial stratification, it is found that the observations set an upper limit on the thermal electron scattering optical depth in the central synchrotron-emitting region of an AGN. The upper limit, tau(max) about 1, results mainly from the apparent absence of induced Compton scattering and inverse thermal Comptonization effects. The low value of tau(max) poses some problems for nonthermal models of the AGN continuum that can be partly resolved by assuming a thin disk or layer-like geometry for the source, with (h/R) less than about 0.01. A likely site for the synchrotron-producing region seems to be the surface of an accretion disk or torus. 20 refs

  8. THREE-YEAR SWIFT-BAT SURVEY OF ACTIVE GALACTIC NUCLEI: RECONCILING THEORY AND OBSERVATIONS?

    International Nuclear Information System (INIS)

    Burlon, D.; Greiner, J.; Merloni, A.; Ajello, M.; Comastri, A.; Gehrels, N.

    2011-01-01

    It is well accepted that unabsorbed as well as absorbed active galactic nuclei (AGNs) are needed to explain the nature and shape of the Cosmic X-ray background (CXB), even if the fraction of highly absorbed objects (dubbed Compton-thick sources) still substantially escapes detection. We derive and analyze the absorption distribution using a complete sample of AGNs detected by Swift-BAT in the first three years of the survey. The fraction of Compton-thick AGNs represents only 4.6% of the total AGN population detected by Swift-BAT. However, we show that once corrected for the bias against the detection of very absorbed sources the real intrinsic fraction of Compton-thick AGNs is 20 -6 +9 %. We proved for the first time (also in the Burst Alert Telescope (BAT) band) that the anti-correlation of the fraction of absorbed AGNs and luminosity is tightly connected to the different behavior of the X-ray luminosity functions (XLFs) of absorbed and unabsorbed AGNs. This points toward a difference between the two subsamples of objects with absorbed AGNs being, on average, intrinsically less luminous than unobscured ones. Moreover, the XLFs show that the fraction of obscured AGNs might also decrease at very low luminosity. This can be successfully interpreted in the framework of a disk cloud outflow scenario as the disappearance of the obscuring region below a critical luminosity. Our results are discussed in the framework of population synthesis models and the origin of the CXB.

  9. Type II NKT cells: a distinct CD1d-restricted immune regulatory NKT cell subset.

    Science.gov (United States)

    Dasgupta, Suryasarathi; Kumar, Vipin

    2016-08-01

    Type II natural killer T cells (NKT) are a subset of the innate-like CD1d-restricted lymphocytes that are reactive to lipid antigens. Unlike the type I NKT cells, which express a semi-invariant TCR, type II NKT cells express a broader TCR repertoire. Additionally, other features, such as their predominance over type I cells in humans versus mice, the nature of their ligands, CD1d/lipid/TCR binding, and modulation of immune responses, distinguish type II NKT cells from type I NKT cells. Interestingly, it is the self-lipid-reactivity of type II NKT cells that has helped define their physiological role in health and in disease. The discovery of sulfatide as one of the major antigens for CD1d-restricted type II NKT cells in mice has been instrumental in the characterization of these cells, including the TCR repertoire, the crystal structure of the CD1d/lipid/TCR complex, and their function. Subsequently, several other glycolipids and phospholipids from both endogenous and microbial sources have been shown to activate type II NKT cells. The activation of a specific subset of type II NKT cells following administration with sulfatide or lysophosphatidylcholine (LPC) leads to engagement of a dominant immunoregulatory pathway associated with the inactivation of type I NKT cells, conventional dendritic cells, and inhibition of the proinflammatory Th1/Th17 cells. Thus, type II NKT cells have been shown to be immunosuppressive in autoimmune diseases, inflammatory liver diseases, and in cancer. Knowing their relatively higher prevalence in human than type I NKT cells, understanding their biology is imperative for health and disease.

  10. Membrane potential and ion transport in lung epithelial type II cells

    International Nuclear Information System (INIS)

    Gallo, R.L.

    1986-01-01

    The alveolar type II pneumocyte is critically important to the function and maintenance of pulmonary epithelium. To investigate the nature of the response of type II cells to membrane injury, and describe a possible mechanism by which these cells regulate surfactant secretion, the membrane potential of isolated rabbit type II cells was characterized. This evaluation was accomplished by measurements of the accumulation of the membrane potential probes: [ 3 H]triphenylmethylphosphonium ([ 3 H]TPMP + ), rubidium 86, and the fluorescent dye DiOC 5 . A compartmental analysis of probe uptake into mitochondrial, cytoplasmic, and non-membrane potential dependent stores was made through the use of selective membrane depolarizations with carbonycyanide M-chlorophenylhydrazone (CCCP), and lysophosphatidylcholine (LPC). These techniques and population analysis with flow cytometry, permitted the accurate evaluation of type II cell membrane potential under control conditions and under conditions which stimulated cell activity. Further analysis of ion transport by cells exposed to radiation or adrenergic stimulation revealed a common increase in Na + /K + ATPase activity, and an increase in sodium influx across the plasma membrane. This sodium influx was found to be a critical step in the initiation of surfactant secretion. It is concluded that radiation exposure as well as other pulmonary toxicants can directly affect the membrane potential and ionic regulation of type II cells. Ion transport, particularly of sodium, plays an important role in the regulation of type II cell function

  11. Type II supernovae modelisation: neutrinos transport simulation

    International Nuclear Information System (INIS)

    Mellor, P.

    1988-10-01

    A modelisation of neutrino transport in type II supernovae is presented. The first part is a description of hydrodynamics and radiative processes responsible of supernovae explosions. Macroscopic aspects of these are displayed in part two. Neutrino transport theory and usual numerical methods are also developed. A new technic of coherent scattering of neutrinos on nuclei or free nucleons is proposed in the frame work of the Lorentz bifluid approximation. This method deals with all numerical artifices (flux limiting schemes, closure relationship of Eddington moments) and allows a complete and consistent determination of the time-dependent neutrino distribution function for any value of the opacity, gradient of opacity and for all (relativistic) velocity fields of the diffusive medium. Part three is dedicated to microscopic phenomena (electronic capture, chimical composition, etc) which rule neutrinos emission-absorption mechanisms. The numerical treatments of those are presented, and some applications are useful for their parametrization. Finally, an extension of the method to inelastic scattering on light particules (electrons) is described in view to study neutrinos thermalization mechanism [fr

  12. Prompt mechanism of type II supernovae

    International Nuclear Information System (INIS)

    Burrows, A.; Lattimer, J.M.

    1985-01-01

    We report in this Letter on an extensive set of hydrodynamical simulations of the stellar collapse of the cores of massive stars. A new hydro technique and a series of state-of-the art equations of state were employed. The purpose of this project was to understand in detail core implosion and immediate postbounce behavior (first 25 ms) and to investigate the viability of the hydrodynamic mechanism for Type II supernovae. We find that the bounce-shock always stalls upon encountering the massive infalling outer core for the calculated cores of stars between 8 and 25 M/sub sun/ and the standard input physics. In particular, it is found that Nomoto's 8l8 m/sub sun/ star and Woosley, Weaver, and Taam's 10 M/sub sun/ star do not explode via the prompt mechanism. Our conclusions appear to depend not on the details of the progenitor structure calculated by others but rather on the generic nature of these structures

  13. Peripheral artery disease in type II diabetes

    International Nuclear Information System (INIS)

    Ali, Z.; Ahmed, S.M.; Bhutto, A.R.; Chaudhry, A.; Munir, S.M.

    2012-01-01

    Objective: To determine the frequency of peripheral arterial disease (PAD) in type 2 diabetic patients. Study Design: Cross-sectional observational study. Place and Duration of Study: Diabetes Clinic, Medical Unit III, Jinnah Postgraduate Medical Centre, Karachi, from January to June 2010. Methodology:Three hundred and eighty seven (387) type II diabetic patients of either gender and any age were included. Patients with a previous history of trauma to the arterial vasculature, pregnancy and those who underwent in the study arterial graft procedures were excluded. Non-purposive convenient sampling technique was used to enroll patients in the study. PAD was diagnosed when ankle-brachial index (ABI) was less than 0.9. Ap-value of less than 0.05 was considered statistically significant. Results: Out of 387 studied patients, 128 were males (33.1%) and 259 were females (66.9%). Mean age was 52.22 +- 6.39 years. PAD was detected in 152 9.671 (22 - 76) years in the entire cohort. Mean duration of diabetes was 9.38 +- (39.28%) of the total study subjects. Thirty-one of 128 male patients (24.22%) had PAD disease while 121 out of 259 female patients (46.71%) had evidence of PAD (p = 0.001). Hypertension was a significantly associated factor (p = 0.002). Conclusion: A high frequency of PAD was observed in the diabetic population particularly with hypertension and more prevalent in females. (author)

  14. The hydrodynamics of Type II supernove

    International Nuclear Information System (INIS)

    Chevalier, R.A.

    1976-01-01

    Observations of Type II supernovae indicate the presence of a moderately cool expanding photosphere. This situation can result from an explosion in a star with an extended envelope. The evolutionary phases of an explosion are described. Information on the propagation of the shock wave through the star can be obtained from γ=4/3 blast wave solutions. If the photon mean free path becomes large compared to the length scales of the flow, a thermal wave moves out from the shock wave and a dense shell is formed behind the shock. The arrival of the shock wave at the photosphere is accompanied by ultraviolet and X-ray burst. As the star expands, a rarefaction wave converts internal energy into kinetic energy. Detailed hydrodynamic models have been calculated, assuming an initial radius compatible with stellar evolution and an energy compatible with the observed velocities. The observed values of photospheric radius and temperature near maximum light are reproduced. Features of the models which are consistent with observation are: the ejection of a detached shell; the cooling of the photosphere from 10,000 K to 6000 K in tens of days after maximum visual light; the shape of the light curve around maximum; the decrease in the velocity of the gas at the photosphere in tens of days after maximum; and a photospheric radius of about 10/sup 14/ cm after several hundred days

  15. Late-onset Bartter syndrome type II.

    Science.gov (United States)

    Gollasch, Benjamin; Anistan, Yoland-Marie; Canaan-Kühl, Sima; Gollasch, Maik

    2017-10-01

    Mutations in the ROMK1 potassium channel gene ( KCNJ1 ) cause antenatal/neonatal Bartter syndrome type II (aBS II), a renal disorder that begins in utero , accounting for the polyhydramnios and premature delivery that is typical in affected infants, who develop massive renal salt wasting, hypokalaemic metabolic alkalosis, secondary hyperreninaemic hyperaldosteronism, hypercalciuria and nephrocalcinosis. This BS type is believed to represent a disorder of the infancy, but not in adulthood. We herein describe a female patient with a remarkably late-onset and mild clinical manifestation of BS II with compound heterozygous KCNJ1 missense mutations, consisting of a novel c.197T > A (p.I66N) and a previously reported c.875G > A (p.R292Q) KCNJ1 mutation. We implemented and evaluated the performance of two different bioinformatics-based approaches of targeted massively parallel sequencing [next generation sequencing (NGS)] in defining the molecular diagnosis. Our results demonstrate that aBS II may be suspected in patients with a late-onset phenotype. Our experimental approach of NGS-based mutation screening combined with Sanger sequencing proved to be a reliable molecular approach for defining the clinical diagnosis in our patient, and results in important differential diagnostic and therapeutic implications for patients with BS. Our results could have a significant impact on the diagnosis and methodological approaches of genetic testing in other patients with clinical unclassified phenotypes of nephrocalcinosis and congenital renal electrolyte abnormalities.

  16. A survey of dual active galactic nuclei in simulations of galaxy mergers: frequency and properties

    Science.gov (United States)

    Capelo, Pedro R.; Dotti, Massimo; Volonteri, Marta; Mayer, Lucio; Bellovary, Jillian M.; Shen, Sijing

    2017-08-01

    We investigate the simultaneous triggering of active galactic nuclei (AGN) in merging galaxies, using a large suite of high-resolution hydrodynamical simulations. We compute dual-AGN observability time-scales using bolometric, X-ray and Eddington-ratio thresholds, confirming that dual activity from supermassive black holes (BHs) is generally higher at late pericentric passages, before a merger remnant has formed, especially at high luminosities. For typical minor and major mergers, dual activity lasts ˜20-70 and ˜100-160 Myr, respectively. We also explore the effects of X-ray obscuration from gas, finding that the dual-AGN time decreases at most by a factor of ˜2, and of contamination from star formation. Using projected separations and velocity differences rather than three-dimensional quantities can decrease the dual-AGN time-scales by up to ˜4, and we apply filters that mimic current observational-resolution limitations. In agreement with observations, we find that for a sample of major and minor mergers hosting at least one AGN, the fraction harbouring dual AGN is ˜20-30 and ˜1-10 per cent, respectively. We quantify the effects of merger mass ratio (0.1 to 1), geometry (coplanar, prograde and retrograde, and inclined), disc gas fraction and BH properties, finding that the mass ratio is the most important factor, with the difference between minor and major mergers varying between factors of a few to orders of magnitude, depending on the luminosity and filter used. We also find that a shallow imaging survey will require very high angular resolution whereas a deep imaging survey will be less resolution-dependent.

  17. Science of active galactic nuclei with the GTC and CanariCam

    Science.gov (United States)

    Levenson, Nancy A.; Packham, Christopher C.; Alonso-Herrero, Almudena; Aretxaga, Itziar; Colina, Luis; Díaz-Santos, Tanio; Elitzur, Moshe; Mason, Rachel E.; Perlman, Eric S.; Radomski, James T.; Roche, Patrick F.; Rodríguez Espinosa, José Miguel; Young, Stuart; Telesco, Charles M.

    2008-07-01

    CanariCam is the facility mid-infrared (MIR) instrument for the Gran Telescopio Canarias (GTC), a 10.4m telescope at the Observatorio del Roque de los Muchachos on La Palma. One of the science drivers for CanariCam is the study of active galactic nuclei (AGN). We will exploit the instrument's high sensitivity in imaging, spectroscopy, and polarimetry modes to answer fundamental questions of AGN and their host galaxies. Dust in the nucleus of an active galaxy reprocesses the intrinsic radiation of the central engine to emerge in the MIR. Current work demonstrates that the hot dust immediately associated with the AGN, which blocks direct views of the AGN from some lines of sight, is confined to small (parsec) scales. Thus, high spatial resolution is essential to probe the "torus" of unified AGN models separate from the host galaxy. CanariCam provides a 0.08" pixel scale for Nyquist sampling the diffraction-limited point spread function at 8μm, and narrow (0.2") spectroscopy slits (with R=120-1300). New observations with the GTC/CanariCam will provide key constraints on the physical conditions in the clumpy torus, and we will sensitively determine AGN obscuration as a function of nuclear activity. We will therefore address the fueling process and its relationship to the torus, the interaction with the host galaxy, and dust chemistry. These data will be essential preparation for the next generation of telescopes that will observe the distant universe directly to explore galaxy and black hole formation and evolution, and the GTC/CanariCam system uniquely provides multiple modes to probe AGN.

  18. Galactic structure

    International Nuclear Information System (INIS)

    1989-01-01

    The occurrence of hot, apparently normal, massive stars far from the galactic plane has been a major puzzle in an understanding of galactic structure and evolution. Such stars have been discovered and studied at the South African Astronomical Observatory (SAAO) over a number of years. During 1989 further evidence has been obtained indicating that these stars are normal, massive objects. Other studies of galactic structure conducted by the SAAO have included research on: the central bulge region of our galaxy; populations of M giants in the galaxy; a faint blue object survey; a survey of the galactic plane for distant Cepheid variables; interstellar reddening, and K-type dwarfs as tracers for the gravitational force perpendicular to the galactic plane. 1 fig

  19. Unveiling the nature of the γ-ray emitting active galactic nucleus PKS 0521-36

    International Nuclear Information System (INIS)

    D'Ammando, F.; Istituto Nazionale di Astrofisica; Orienti, M.; Tavecchio, F.; Ghisellini, G.

    2015-01-01

    PKS 0521-36 is an active galactic nucleus (AGN) with uncertain classification. Here, we investigate the properties of this source from radio to γ-rays. The broad emission lines in the optical and ultraviolet bands and steep radio spectrum indicate a possible classification as an intermediate object between broad-line radio galaxies (BLRG) and steep spectrum radio quasars (SSRQ). On pc-scales PKS 0521-36 shows a knotty structure similar to misaligned AGN. The core dominance and the γ-ray properties are similar to those estimated for other SSRQ and BLRG detected in γ-rays, suggesting an intermediate viewing angle with respect to the observer. In this context the flaring activity detected from this source by Fermi-Large Area Telescope between 2010 June and 2012 February is very intriguing. We discuss the γ-ray emission of this source in the framework of the structured jet scenario, comparing the spectral energy distribution (SED) of the flaring state in 2010 June with that of a low state. We present three alternative models corresponding to three different choices of the viewing angles θv = 6°, 15°, and 20°. We obtain a good fit for the first two cases, but the SED obtained with θv = 15° if observed at a small angle does not resemble that of a typical blazar since the synchrotron emission should dominate by a large factor (~100) the inverse Compton component. This suggests that a viewing angle between 6° and 15° is preferred, with the rapid variability observed during γ-ray flares favouring a smaller angle. However, we cannot rule out that PKS 0521-36 is the misaligned counterpart of a synchrotron-dominated blazar.

  20. Multiwavelength observations of Active Galactic Nuclei from the radio to the hard X-rays

    Science.gov (United States)

    Beuchert, Tobias

    2017-07-01

    Active Galaxies form a peculiar type of galaxies. Their cores, the so-called "Active Galactic Nuclei" (AGN), are the most persistent luminous objects in the universe. Accretion of several solar masses per year onto black holes of Millions to Billions of solar masses drive the immense energy output of these systems, which can exceed that of the entire galaxy. The compact energy source, however, only measures about one over a Billion times that of the entire galaxy. Subject of my thesis are observations of the two main channels of energy release of selected AGN systems, both of which are encompassed by profound and yet unanswered questions. These channels are on the one hand the pronounced X-ray emission of the hot and compact accreting environment in close vicinity of the black hole, and on the other hand the radio synchrotron emission of magnetically collimated jets that are fed by portions of the accreted matter. These jets also function as effective accelerators and drive the injected matter deep into the intergalactic medium. As the circumnuclear environment of AGN is too compact to be spatially resolved in the X-rays, I show how X-ray spectroscopy can be used to: (1) understand the effects of strong gravity to trace the geometry and physics of the X-ray source and (2) more consistently quantify matter that surrounds and dynamically absorbs our direct line of sight towards the X-ray source. Second, I unveil the valuable information contained in the polarized radio light being emitted from magnetized jet outflows. In contrast to the X-ray emitting region, I am able to spatially resolve the inner parts of the jet of a prominent galaxy with help of the Very Long Baseline Array, a large network of radio telescopes. The resulting polarization maps turn out to be exceptionally promising in answering fundamental questions related to jet physics.

  1. The typecasting of active galactic nuclei: Mrk 590 no longer fits the role

    Energy Technology Data Exchange (ETDEWEB)

    Denney, K. D.; De Rosa, G.; Croxall, K.; Gupta, A.; Fausnaugh, M. M.; Grier, C. J.; Martini, P.; Mathur, S.; Peterson, B. M.; Pogge, R. W.; Shappee, B. J. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Bentz, M. C., E-mail: denney@astronomy.ohio-state.edu [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States)

    2014-12-01

    We present multiwavelength observations that trace more than 40 yr in the life of the active galactic nucleus (AGN) in Mrk 590, traditionally known as a classic Seyfert 1 galaxy. From spectra recently obtained from Hubble Space Telescope, Chandra, and the Large Binocular Telescope, we find that the activity in the nucleus of Mrk 590 has diminished so significantly that the continuum luminosity is a factor of 100 lower than the peak luminosity probed by our long-baseline observations. Furthermore, the broad emission lines, once prominent in the UV/optical spectrum, have all but disappeared. Since AGN type is defined by the presence of broad emission lines in the optical spectrum, our observations demonstrate that Mrk 590 has now become a 'changing-look' AGN. If classified by recent optical spectra, Mrk 590 would be a Seyfert ∼1.9–2, where the only broad emission line still visible in the optical spectrum is a weak component of Hα. As an additional consequence of this change, we have definitively detected UV narrow-line components in a Type 1 AGN, allowing an analysis of these emission-line components with high-resolution COS spectra. These observations challenge the historical paradigm that AGN type is only a consequence of the line-of-sight viewing angle toward the nucleus in the presence of a geometrically flattened, obscuring medium (i.e., the torus). Our data instead suggest that the current state of Mrk 590 is a consequence of the change in luminosity, which implies the black hole accretion rate has significantly decreased.

  2. The typecasting of active galactic nuclei: Mrk 590 no longer fits the role

    International Nuclear Information System (INIS)

    Denney, K. D.; De Rosa, G.; Croxall, K.; Gupta, A.; Fausnaugh, M. M.; Grier, C. J.; Martini, P.; Mathur, S.; Peterson, B. M.; Pogge, R. W.; Shappee, B. J.; Bentz, M. C.

    2014-01-01

    We present multiwavelength observations that trace more than 40 yr in the life of the active galactic nucleus (AGN) in Mrk 590, traditionally known as a classic Seyfert 1 galaxy. From spectra recently obtained from Hubble Space Telescope, Chandra, and the Large Binocular Telescope, we find that the activity in the nucleus of Mrk 590 has diminished so significantly that the continuum luminosity is a factor of 100 lower than the peak luminosity probed by our long-baseline observations. Furthermore, the broad emission lines, once prominent in the UV/optical spectrum, have all but disappeared. Since AGN type is defined by the presence of broad emission lines in the optical spectrum, our observations demonstrate that Mrk 590 has now become a 'changing-look' AGN. If classified by recent optical spectra, Mrk 590 would be a Seyfert ∼1.9–2, where the only broad emission line still visible in the optical spectrum is a weak component of Hα. As an additional consequence of this change, we have definitively detected UV narrow-line components in a Type 1 AGN, allowing an analysis of these emission-line components with high-resolution COS spectra. These observations challenge the historical paradigm that AGN type is only a consequence of the line-of-sight viewing angle toward the nucleus in the presence of a geometrically flattened, obscuring medium (i.e., the torus). Our data instead suggest that the current state of Mrk 590 is a consequence of the change in luminosity, which implies the black hole accretion rate has significantly decreased.

  3. Anti-hierarchical evolution of the active galactic nucleus space density in a hierarchical universe

    International Nuclear Information System (INIS)

    Enoki, Motohiro; Ishiyama, Tomoaki; Kobayashi, Masakazu A. R.; Nagashima, Masahiro

    2014-01-01

    Recent observations show that the space density of luminous active galactic nuclei (AGNs) peaks at higher redshifts than that of faint AGNs. This downsizing trend in the AGN evolution seems to be contradictory to the hierarchical structure formation scenario. In this study, we present the AGN space density evolution predicted by a semi-analytic model of galaxy and AGN formation based on the hierarchical structure formation scenario. We demonstrate that our model can reproduce the downsizing trend of the AGN space density evolution. The reason for the downsizing trend in our model is a combination of the cold gas depletion as a consequence of star formation, the gas cooling suppression in massive halos, and the AGN lifetime scaling with the dynamical timescale. We assume that a major merger of galaxies causes a starburst, spheroid formation, and cold gas accretion onto a supermassive black hole (SMBH). We also assume that this cold gas accretion triggers AGN activity. Since the cold gas is mainly depleted by star formation and gas cooling is suppressed in massive dark halos, the amount of cold gas accreted onto SMBHs decreases with cosmic time. Moreover, AGN lifetime increases with cosmic time. Thus, at low redshifts, major mergers do not always lead to luminous AGNs. Because the luminosity of AGNs is correlated with the mass of accreted gas onto SMBHs, the space density of luminous AGNs decreases more quickly than that of faint AGNs. We conclude that the anti-hierarchical evolution of the AGN space density is not contradictory to the hierarchical structure formation scenario.

  4. Anti-hierarchical evolution of the active galactic nucleus space density in a hierarchical universe

    Energy Technology Data Exchange (ETDEWEB)

    Enoki, Motohiro [Faculty of Business Administration, Tokyo Keizai University, Kokubunji, Tokyo 185-8502 (Japan); Ishiyama, Tomoaki [Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Kobayashi, Masakazu A. R. [Research Center for Space and Cosmic Evolution, Ehime University, Matsuyama, Ehime 790-8577 (Japan); Nagashima, Masahiro, E-mail: enokimt@tku.ac.jp [Faculty of Education, Nagasaki University, Nagasaki, Nagasaki 852-8521 (Japan)

    2014-10-10

    Recent observations show that the space density of luminous active galactic nuclei (AGNs) peaks at higher redshifts than that of faint AGNs. This downsizing trend in the AGN evolution seems to be contradictory to the hierarchical structure formation scenario. In this study, we present the AGN space density evolution predicted by a semi-analytic model of galaxy and AGN formation based on the hierarchical structure formation scenario. We demonstrate that our model can reproduce the downsizing trend of the AGN space density evolution. The reason for the downsizing trend in our model is a combination of the cold gas depletion as a consequence of star formation, the gas cooling suppression in massive halos, and the AGN lifetime scaling with the dynamical timescale. We assume that a major merger of galaxies causes a starburst, spheroid formation, and cold gas accretion onto a supermassive black hole (SMBH). We also assume that this cold gas accretion triggers AGN activity. Since the cold gas is mainly depleted by star formation and gas cooling is suppressed in massive dark halos, the amount of cold gas accreted onto SMBHs decreases with cosmic time. Moreover, AGN lifetime increases with cosmic time. Thus, at low redshifts, major mergers do not always lead to luminous AGNs. Because the luminosity of AGNs is correlated with the mass of accreted gas onto SMBHs, the space density of luminous AGNs decreases more quickly than that of faint AGNs. We conclude that the anti-hierarchical evolution of the AGN space density is not contradictory to the hierarchical structure formation scenario.

  5. NEAR-INFRARED REVERBERATION BY DUSTY CLUMPY TORI IN ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Kawaguchi, Toshihiro; Mori, Masao

    2011-01-01

    According to recent models, the accretion disk and black hole in active galactic nuclei (AGNs) are surrounded by a clumpy torus. We investigate the NIR flux variation of the torus in response to a UV flash for various geometries. Anisotropic illumination by the disk and the torus self-occultation contrast our study with earlier works. Both the waning effect of each clump and the torus self-occultation selectively reduce the emission from the region with a short delay. Therefore, the NIR delay depends on the viewing angle (where a more inclined angle leads to a longer delay), and the time response shows an asymmetric profile with negative skewness, opposing the results for optically thin tori. The range of the computed delay coincides with the observed one, suggesting that the viewing angle is primarily responsible for the scatter of the observed delay. We also propose that the red NIR-to-optical color of type 1.8/1.9 objects is caused not only by the dust extinction but also the intrinsically red color. Compared with the modest torus thickness, both a thick and a thin tori display weaker NIR emission. A selection bias is thus expected such that NIR-selected AGNs tend to possess moderately thick tori. A thicker torus shows a narrower and more heavily skewed time profile, while a thin torus produces a rapid response. A super-Eddington accretion rate leads to much weaker NIR emission due to the disk self-occultation and the disk truncation by self-gravity. A long delay is expected from an optically thin and/or a largely misaligned torus. Very weak NIR emission, such as in hot-dust-poor active nuclei, can arise from a geometrically thin torus, a super-Eddington accretion rate, or a slightly misaligned torus.

  6. The velocities of type II solar radio bursts

    International Nuclear Information System (INIS)

    Tlamicha, A.; Karlicky, M.

    1976-01-01

    A list is presented of type II radio bursts identified at Ondrejov between January 1973 and December 1974 in the frequency range of the dynamic spectrum 70 to 810 MHz. The velocities of shock waves in the individual cases of type II bursts are given using the fourfold Newkirk model. Some problems associated with type II radio bursts and with the propagation of the shock wave into the interplanetary space and into the region of the Earth are also discussed. (author)

  7. Nonlocal conductivity in type-II superconductors

    International Nuclear Information System (INIS)

    Mou, C.; Wortis, R.; Dorsey, A.T.; Huse, D.A.

    1995-01-01

    Multiterminal transport measurements on YBa 2 Cu 2 O 7 crystals in the vortex liquid regime have shown nonlocal conductivity on length scales up to 50 microns. Motivated by these results we explore the wave vector (k) dependence of the dc conductivity tensor, σ μν (k), in the Meissner, vortex lattice, and disordered phases of a type-II superconductor. Our results are based on time-dependent Ginzburg-Landau (TDGL) theory and on phenomenological arguments. We find four qualitatively different types of behavior. First, in the Meissner phase, the conductivity is infinite at k=0 and is a continuous function of k, monotonically decreasing with increasing k. Second, in the vortex-lattice phase, in the absence of pinning, the conductivity is finite (due to flux flow) at k=0; it is discontinuous there and remains qualitatively like the Meissner phase for k>0. Third, in the vortex liquid regime in a magnetic field and at low temperature, the conductivity is finite, smooth and nonmonotonic, first increasing with k at small k and then decreasing at larger k. This third behavior is expected to apply at temperatures just above the melting transition of the vortex lattice, where the vortex liquid shows strong short-range order and a large viscosity. Finally, at higher temperatures in the disordered phase, the conductivity is finite, smooth and again monotonically decreasing with k. This last, monotonic behavior applies in zero magnetic field for the entire disordered phase, i.e., at all temperatures above T c , while in a field the nonmonotonic behavior may occur in a low-temperature portion of the disordered phase

  8. Type II superlattice technology for LWIR detectors

    Science.gov (United States)

    Klipstein, P. C.; Avnon, E.; Azulai, D.; Benny, Y.; Fraenkel, R.; Glozman, A.; Hojman, E.; Klin, O.; Krasovitsky, L.; Langof, L.; Lukomsky, I.; Nitzani, M.; Shtrichman, I.; Rappaport, N.; Snapi, N.; Weiss, E.; Tuito, A.

    2016-05-01

    SCD has developed a range of advanced infrared detectors based on III-V semiconductor heterostructures grown on GaSb. The XBn/XBp family of barrier detectors enables diffusion limited dark currents, comparable with MCT Rule-07, and high quantum efficiencies. This work describes some of the technical challenges that were overcome, and the ultimate performance that was finally achieved, for SCD's new 15 μm pitch "Pelican-D LW" type II superlattice (T2SL) XBp array detector. This detector is the first of SCD's line of high performance two dimensional arrays working in the LWIR spectral range, and was designed with a ~9.3 micron cut-off wavelength and a format of 640 x 512 pixels. It contains InAs/GaSb and InAs/AlSb T2SLs, engineered using k • p modeling of the energy bands and photo-response. The wafers are grown by molecular beam epitaxy and are fabricated into Focal Plane Array (FPA) detectors using standard FPA processes, including wet and dry etching, indium bump hybridization, under-fill, and back-side polishing. The FPA has a quantum efficiency of nearly 50%, and operates at 77 K and F/2.7 with background limited performance. The pixel operability of the FPA is above 99% and it exhibits a stable residual non uniformity (RNU) of better than 0.04% of the dynamic range. The FPA uses a new digital read-out integrated circuit (ROIC), and the complete detector closely follows the interfaces of SCD's MWIR Pelican-D detector. The Pelican- D LW detector is now in the final stages of qualification and transfer to production, with first prototypes already integrated into new electro-optical systems.

  9. Policing starter unit selection of the enterocin type II polyketide synthase by the type II thioesterase EncL.

    Science.gov (United States)

    Kalaitzis, John A; Cheng, Qian; Meluzzi, Dario; Xiang, Longkuan; Izumikawa, Miho; Dorrestein, Pieter C; Moore, Bradley S

    2011-11-15

    Enterocin is an atypical type II polyketide synthase (PKS) product from the marine actinomycete 'Streptomyces maritimus'. The enterocin biosynthesis gene cluster (enc) codes for proteins involved in the assembly and attachment of the rare benzoate primer that initiates polyketide assembly with the addition of seven malonate molecules and culminates in a Favorskii-like rearrangement of the linear poly-β-ketone to give its distinctive non-aromatic, caged core structure. Fundamental to enterocin biosynthesis, which utilizes a single acyl carrier protein (ACP), EncC, for both priming with benzoate and elongating with malonate, involves maintaining the correct balance of acyl-EncC substrates for efficient polyketide assembly. Here, we report the characterization of EncL as a type II thioesterase that functions to edit starter unit (mis)priming of EncC. We performed a series of in vivo mutational studies, heterologous expression experiments, in vitro reconstitution studies, and Fourier-transform mass spectrometry-monitored competitive enzyme assays that together support the proposed selective hydrolase activity of EncL toward misprimed acetyl-ACP over benzoyl-ACP to facilitate benzoyl priming of the enterocin PKS complex. While this system resembles the R1128 PKS that also utilizes an editing thioesterase (ZhuC) to purge acetate molecules from its initiation module ACP in favor of alkylacyl groups, the enterocin system is distinct in its usage of a single ACP for both priming and elongating reactions with different substrates. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Self-dual nonsupersymmetric Type II String Compactifications

    International Nuclear Information System (INIS)

    Kachru, Shamit; Silverstein, Eva

    1998-01-01

    It has recently been proposed that certain nonsupersymmetric type II orbifolds have vanishing perturbative contributions to the cosmological constant. We show that techniques of Sen and Vafa allow one to construct dual type II descriptions of these models (some of which have no weakly coupled heterotic dual). The dual type II models are given by the same orbifolds with the string coupling S and a T 2 volume T exchanged. This allows us to argue that in various strongly coupled limits of the original type II models, there are weakly coupled duals which exhibit the same perturbative cancellations as the original models

  11. ACh-induced hyperpolarization and decreased resistance in mammalian type II vestibular hair cells.

    Science.gov (United States)

    Poppi, Lauren A; Tabatabaee, Hessam; Drury, Hannah R; Jobling, Phillip; Callister, Robert J; Migliaccio, Americo A; Jordan, Paivi M; Holt, Joseph C; Rabbitt, Richard D; Lim, Rebecca; Brichta, Alan M

    2018-01-01

    In the mammalian vestibular periphery, electrical activation of the efferent vestibular system (EVS) has two effects on afferent activity: 1) it increases background afferent discharge and 2) decreases afferent sensitivity to rotational stimuli. Although the cellular mechanisms underlying these two contrasting afferent responses remain obscure, we postulated that the reduction in afferent sensitivity was attributed, in part, to the activation of α9- containing nicotinic acetylcholine (ACh) receptors (α9*nAChRs) and small-conductance potassium channels (SK) in vestibular type II hair cells, as demonstrated in the peripheral vestibular system of other vertebrates. To test this hypothesis, we examined the effects of the predominant EVS neurotransmitter ACh on vestibular type II hair cells from wild-type (wt) and α9-subunit nAChR knockout (α9 -/- ) mice. Immunostaining for choline acetyltransferase revealed there were no obvious gross morphological differences in the peripheral EVS innervation among any of these strains. ACh application onto wt type II hair cells, at resting potentials, produced a fast inward current followed by a slower outward current, resulting in membrane hyperpolarization and decreased membrane resistance. Hyperpolarization and decreased resistance were due to gating of SK channels. Consistent with activation of α9*nAChRs and SK channels, these ACh-sensitive currents were antagonized by the α9*nAChR blocker strychnine and SK blockers apamin and tamapin. Type II hair cells from α9 -/- mice, however, failed to respond to ACh at all. These results confirm the critical importance of α9nAChRs in efferent modulation of mammalian type II vestibular hair cells. Application of exogenous ACh reduces electrical impedance, thereby decreasing type II hair cell sensitivity. NEW & NOTEWORTHY Expression of α9 nicotinic subunit was crucial for fast cholinergic modulation of mammalian vestibular type II hair cells. These findings show a multifaceted

  12. Galactic dynamics

    CERN Document Server

    Binney, James

    2008-01-01

    Since it was first published in 1987, Galactic Dynamics has become the most widely used advanced textbook on the structure and dynamics of galaxies and one of the most cited references in astrophysics. Now, in this extensively revised and updated edition, James Binney and Scott Tremaine describe the dramatic recent advances in this subject, making Galactic Dynamics the most authoritative introduction to galactic astrophysics available to advanced undergraduate students, graduate students, and researchers. Every part of the book has been thoroughly overhauled, and many section

  13. Examining the High-energy Radiation Mechanisms of Knots and Hotspots in Active Galactic Nucleus Jets

    Science.gov (United States)

    Zhang, Jin; Du, Shen-shi; Guo, Sheng-Chu; Zhang, Hai-Ming; Chen, Liang; Liang, En-Wei; Zhang, Shuang-Nan

    2018-05-01

    We compile the radio–optical–X-ray spectral energy distributions (SEDs) of 65 knots and 29 hotspots in 41 active galactic nucleus jets to examine their high-energy radiation mechanisms. Their SEDs can be fitted with the single-zone leptonic models, except for the hotspot of Pictor A and six knots of 3C 273. The X-ray emission of 1 hotspot and 22 knots is well explained as synchrotron radiation under the equipartition condition; they usually have lower X-ray and radio luminosities than the others, which may be due to a lower beaming factor. An inverse Compton (IC) process is involved for explaining the X-ray emission of the other SEDs. Without considering the equipartition condition, their X-ray emission can be attributed to the synchrotron-self-Compton process, but the derived jet powers (P jet) are not correlated with L k and most of them are larger than L k, with more than three orders of magnitude, where L k is the jet kinetic power estimated with their radio emission. Under the equipartition condition, the X-ray emission is well interpreted with the IC process for the cosmic microwave background photons (IC/CMB). In this scenario, the derived P jet of knots and hotspots are correlated with and comparable to L k. These results suggest that the IC/CMB model may be a promising interpretation of the X-ray emission. In addition, a tentative knot–hotspot sequence in the synchrotron peak-energy–peak-luminosity plane is observed, similar to the blazar sequence, which may be attributed to the different cooling mechanisms of electrons.

  14. WHAT GOVERNS THE BULK VELOCITY OF THE JET COMPONENTS IN ACTIVE GALACTIC NUCLEI?

    International Nuclear Information System (INIS)

    Chai Bo; Cao Xinwu; Gu Minfeng

    2012-01-01

    We use a sample of radio-loud active galactic nuclei (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. Based on Königl's inhomogeneous jet model, the jet parameters, such as the bulk motion Lorentz factor, magnetic field strength, and electron density in the jet, can be estimated with the very long baseline interferometry and X-ray data.. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is present between the bulk Lorentz factor and the Eddington ratio. The massive black holes will be spun up through accretion, as the black holes acquire mass and angular momentum simultaneously through accretion. Recent investigation indeed suggested that most supermassive black holes in elliptical galaxies have on average higher spins than the black holes in spiral galaxies, where random, small accretion episodes (e.g., tidally disrupted stars, accretion of molecular clouds) might have played a more important role. If this is true, then the correlation between black hole mass and the bulk Lorentz factor of the jet components found in this work implies that the motion velocity of the jet components is probably governed by the black hole spin. No correlation is found between the magnetic field strength at 10R S (R S = 2GM/c 2 is the Schwarzschild radius) in the jets and the bulk Lorentz factor of the jet components for this sample. This is consistent with the black hole spin scenario, i.e., the faster moving jets are magnetically accelerated by the magnetic fields threading the horizon of more rapidly rotating black holes. The results imply that the Blandford-Znajek mechanism may dominate over the Blandford-Payne mechanism for the jet acceleration, at least in these radio-loud AGNs.

  15. Q2122-444: A NAKED ACTIVE GALACTIC NUCLEUS FULLY DRESSED

    International Nuclear Information System (INIS)

    Gliozzi, M.; Satyapal, S.; Panessa, F.; Franca, F. La; Saviane, I.; Monaco, L.; Foschini, L.; Kedziora-Chudczer, L.; Sambruna, R. M.

    2010-01-01

    Based on previous spectral and temporal optical studies, Q2122-444 has been classified as a naked active galactic nucleus (AGN) or true type 2 AGN, that is, an AGN that genuinely lacks a broad-line region (BLR). Its optical spectrum seemed to possess only narrow forbidden emission lines that are typical of type 2 (obscured) AGNs, but the long-term optical light curve, obtained from a monitoring campaign over more than two decades, showed strong variability, apparently ruling out the presence of heavy obscuration. Here we present the results from a ∼40 ks XMM-Newton observation of Q2122-444 carried out to shed light on the energetics of this enigmatic AGN. The X-ray analysis was complemented with Australia Telescope Compact Array radio data to assess the possible presence of a jet, and with new NTT/EFOSC2 optical spectroscopic data to verify the actual absence of a BLR. The higher-quality optical data revealed the presence of strong and broad Balmer lines that are at odds with the previous spectral classification of this AGN. The lack of detection of radio emission rules out the presence of a jet. The X-ray data combined with simultaneous UV observations carried out by the Optical Monitor (OM) aboard XMM-Newton confirm that Q2122-444 is a typical type 1 AGN without any significant intrinsic absorption. New estimates of the black hole mass independently obtained from the broad Balmer lines and from a new scaling technique based on X-ray spectral data suggest that Q2122-444 is accreting at a relatively high rate in Eddington units.

  16. CHARACTERIZING THE OPTICAL VARIABILITY OF BRIGHT BLAZARS: VARIABILITY-BASED SELECTION OF FERMI ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Ruan, John J.; Anderson, Scott F.; MacLeod, Chelsea L.; Becker, Andrew C.; Davenport, James R. A.; Ivezić, Željko; Burnett, T. H.; Kochanek, Christopher S.; Plotkin, Richard M.; Sesar, Branimir; Stuart, J. Scott

    2012-01-01

    We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the ∼30% of γ-ray sources in the Fermi 2FGL catalog still lacking reliable associations. Using data from the optical LINEAR asteroid survey, we characterize the optical variability of blazars by fitting a damped random walk model to individual light curves with two main model parameters, the characteristic timescales of variability τ, and driving amplitudes on short timescales σ-circumflex. Imposing cuts on minimum τ and σ-circumflex allows for blazar selection with high efficiency E and completeness C. To test the efficacy of this approach, we apply this method to optically variable LINEAR objects that fall within the several-arcminute error ellipses of γ-ray sources in the Fermi 2FGL catalog. Despite the extreme stellar contamination at the shallow depth of the LINEAR survey, we are able to recover previously associated optical counterparts to Fermi active galactic nuclei with E ≥ 88% and C = 88% in Fermi 95% confidence error ellipses having semimajor axis r < 8'. We find that the suggested radio counterpart to Fermi source 2FGL J1649.6+5238 has optical variability consistent with other γ-ray blazars and is likely to be the γ-ray source. Our results suggest that the variability of the non-thermal jet emission in blazars is stochastic in nature, with unique variability properties due to the effects of relativistic beaming. After correcting for beaming, we estimate that the characteristic timescale of blazar variability is ∼3 years in the rest frame of the jet, in contrast with the ∼320 day disk flux timescale observed in quasars. The variability-based selection method presented will be useful for blazar identification in time-domain optical surveys and is also a probe of jet physics.

  17. Characterizing the Optical Variability of Bright Blazars: Variability-based Selection of Fermi Active Galactic Nuclei

    Science.gov (United States)

    Ruan, John J.; Anderson, Scott F.; MacLeod, Chelsea L.; Becker, Andrew C.; Burnett, T. H.; Davenport, James R. A.; Ivezić, Željko; Kochanek, Christopher S.; Plotkin, Richard M.; Sesar, Branimir; Stuart, J. Scott

    2012-11-01

    We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the ~30% of γ-ray sources in the Fermi 2FGL catalog still lacking reliable associations. Using data from the optical LINEAR asteroid survey, we characterize the optical variability of blazars by fitting a damped random walk model to individual light curves with two main model parameters, the characteristic timescales of variability τ, and driving amplitudes on short timescales \\hat{\\sigma }. Imposing cuts on minimum τ and \\hat{\\sigma } allows for blazar selection with high efficiency E and completeness C. To test the efficacy of this approach, we apply this method to optically variable LINEAR objects that fall within the several-arcminute error ellipses of γ-ray sources in the Fermi 2FGL catalog. Despite the extreme stellar contamination at the shallow depth of the LINEAR survey, we are able to recover previously associated optical counterparts to Fermi active galactic nuclei with E >= 88% and C = 88% in Fermi 95% confidence error ellipses having semimajor axis r beaming. After correcting for beaming, we estimate that the characteristic timescale of blazar variability is ~3 years in the rest frame of the jet, in contrast with the ~320 day disk flux timescale observed in quasars. The variability-based selection method presented will be useful for blazar identification in time-domain optical surveys and is also a probe of jet physics.

  18. Stellar Photometric Structures of the Host Galaxies of Nearby Type 1 Active Galactic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Minjin [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Peng, Chien Y. [Giant Magellan Telescope Corporation, 251 S. Lake Ave., Suite 300, Pasadena, CA 91101 (United States); Barth, Aaron J. [Department of Physics and Astronomy, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697-4575 (United States); Im, Myungshin, E-mail: mkim@kasi.re.kr, E-mail: lho.pku@gmail.com, E-mail: peng@gmto.org, E-mail: barth@uci.edu, E-mail: mim@astro.snu.ac.kr [Department of Physics and Astronomy, Frontier Physics Research Division (FPRD), Seoul National University, Seoul (Korea, Republic of)

    2017-10-01

    We present detailed image analysis of rest-frame optical images of 235 low-redshift ( z ≲ 0.35) Type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope . The high-resolution images enable us to perform rigorous two-dimensional image modeling to decouple the luminous central point source from the host galaxy, which, when warranted, is further decomposed into its principal structural components (bulge, bar, and disk). In many cases, care must be taken to account for structural complexities such as spiral arms, tidal features, and overlapping or interacting companion galaxies. We employ Fourier modes to characterize the degree of asymmetry of the light distribution of the stars as a quantitative measure of morphological distortion due to interactions or mergers. We examine the dependence of the physical parameters of the host galaxies on the properties of the AGNs, namely, radio-loudness and the width of the broad emission lines. In accordance with previous studies, narrow-line (H β FWHM ≤ 2000 km s{sup −1}) Type 1 AGNs, in contrast to their broad-line (H β FWHM > 2000 km s{sup −1}) counterparts, are preferentially hosted in later-type, lower-luminosity galaxies, which have a higher incidence of pseudo-bulges, are more frequently barred, and are less morphologically disturbed. This suggests that narrow-line Type 1 AGNs experienced a more quiescent evolutionary history driven primarily by internal secular evolution instead of external dynamical perturbations. The fraction of AGN hosts showing merger signatures is larger for more luminous sources. Radio-loud AGNs generally preferentially live in earlier-type (bulge-dominated), more massive hosts, although a minority of them appear to contain a significant disk component. We do not find convincing evidence for enhanced merger signatures in the radio-loud population.

  19. ISOTROPIC HEATING OF GALAXY CLUSTER CORES VIA RAPIDLY REORIENTING ACTIVE GALACTIC NUCLEUS JETS

    International Nuclear Information System (INIS)

    Babul, Arif; Sharma, Prateek; Reynolds, Christopher S.

    2013-01-01

    Active galactic nucleus (AGN) jets carry more than sufficient energy to stave off catastrophic cooling of the intracluster medium (ICM) in the cores of cool-core clusters. However, in order to prevent catastrophic cooling, the ICM must be heated in a near-isotropic fashion and narrow bipolar jets with P jet = 10 44–45 erg s –1 , typical of radio AGNs at cluster centers, are inefficient in heating the gas in the transverse direction to the jets. We argue that due to existent conditions in cluster cores, the supermassive black holes (SMBHs) will, in addition to accreting gas via radiatively inefficient flows, experience short stochastic episodes of enhanced accretion via thin disks. In general, the orientation of these accretion disks will be misaligned with the spin axis of the black holes (BHs) and the ensuing torques will cause the BH's spin axis (and therefore the jet axis) to slew and rapidly change direction. This model not only explains recent observations showing successive generations of jet-lobes-bubbles in individual cool-core clusters that are offset from each other in the angular direction with respect to the cluster center, but also shows that AGN jets can heat the cluster core nearly isotropically on the gas cooling timescale. Our model does require that the SMBHs at the centers of cool-core clusters be spinning relatively slowly. Torques from individual misaligned disks are ineffective at tilting rapidly spinning BHs by more than a few degrees. Additionally, since SMBHs that host thin accretion disks will manifest as quasars, we predict that roughly 1-2 rich clusters within z < 0.5 should have quasars at their centers.

  20. PARSEC-SCALE FARADAY ROTATION MEASURES FROM GENERAL RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS OF ACTIVE GALACTIC NUCLEUS JETS

    International Nuclear Information System (INIS)

    Broderick, Avery E.; McKinney, Jonathan C.

    2010-01-01

    It is now possible to compare global three-dimensional general relativistic magnetohydrodynamic (GRMHD) jet formation simulations directly to multi-wavelength polarized VLBI observations of the pc-scale structure of active galactic nucleus (AGN) jets. Unlike the jet emission, which requires post hoc modeling of the nonthermal electrons, the Faraday rotation measures (RMs) depend primarily upon simulated quantities and thus provide a direct way to confront simulations with observations. We compute RM distributions of a three-dimensional global GRMHD jet formation simulation, extrapolated in a self-consistent manner to ∼10 pc scales, and explore the dependence upon model and observational parameters, emphasizing the signatures of structures generic to the theory of MHD jets. With typical parameters, we find that it is possible to reproduce the observed magnitudes and many of the structures found in AGN jet RMs, including the presence of transverse RM gradients. In our simulations, the RMs are generated in the circum-jet material, hydrodynamically a smooth extension of the jet itself, containing ordered toroidally dominated magnetic fields. This results in a particular bilateral morphology that is unlikely to arise due to Faraday rotation in distant foreground clouds. However, critical to efforts to probe the Faraday screen will be resolving the transverse jet structure. Therefore, the RMs of radio cores may not be reliable indicators of the properties of the rotating medium. Finally, we are able to constrain the particle content of the jet, finding that at pc scales AGN jets are electromagnetically dominated, with roughly 2% of the comoving energy in nonthermal leptons and much less in baryons.

  1. PARSEC-SCALE FARADAY ROTATION MEASURES FROM GENERAL RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS OF ACTIVE GALACTIC NUCLEUS JETS

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Avery E [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada); McKinney, Jonathan C., E-mail: aeb@cita.utoronto.c, E-mail: jmckinne@stanford.ed [Department of Physics and Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305-4060 (United States)

    2010-12-10

    It is now possible to compare global three-dimensional general relativistic magnetohydrodynamic (GRMHD) jet formation simulations directly to multi-wavelength polarized VLBI observations of the pc-scale structure of active galactic nucleus (AGN) jets. Unlike the jet emission, which requires post hoc modeling of the nonthermal electrons, the Faraday rotation measures (RMs) depend primarily upon simulated quantities and thus provide a direct way to confront simulations with observations. We compute RM distributions of a three-dimensional global GRMHD jet formation simulation, extrapolated in a self-consistent manner to {approx}10 pc scales, and explore the dependence upon model and observational parameters, emphasizing the signatures of structures generic to the theory of MHD jets. With typical parameters, we find that it is possible to reproduce the observed magnitudes and many of the structures found in AGN jet RMs, including the presence of transverse RM gradients. In our simulations, the RMs are generated in the circum-jet material, hydrodynamically a smooth extension of the jet itself, containing ordered toroidally dominated magnetic fields. This results in a particular bilateral morphology that is unlikely to arise due to Faraday rotation in distant foreground clouds. However, critical to efforts to probe the Faraday screen will be resolving the transverse jet structure. Therefore, the RMs of radio cores may not be reliable indicators of the properties of the rotating medium. Finally, we are able to constrain the particle content of the jet, finding that at pc scales AGN jets are electromagnetically dominated, with roughly 2% of the comoving energy in nonthermal leptons and much less in baryons.

  2. DISSECTING PHOTOMETRIC REDSHIFT FOR ACTIVE GALACTIC NUCLEUS USING XMM- AND CHANDRA-COSMOS SAMPLES

    International Nuclear Information System (INIS)

    Salvato, M.; Hasinger, G.; Ilbert, O.; Rau, A.; Brusa, M.; Bongiorno, A.; Civano, F.; Elvis, M.; Zamorani, G.; Vignali, C.; Comastri, A.; Bardelli, S.; Bolzonella, M.; Cappelluti, N.; Aussel, H.; Le Floc'h, E.; Fiore, F.; Mainieri, V.; Capak, P.; Caputi, K.

    2011-01-01

    In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of the Cosmic Evolution Survey (COSMOS) field. The availability of a large training set of spectroscopic redshifts that extends to faint magnitudes enabled photometric redshifts comparable to the highest quality results presently available for normal galaxies. We demonstrate that morphologically extended, faint X-ray sources without optical variability are more accurately described by a library of normal galaxies (corrected for emission lines) than by active galactic nucleus (AGN) dominated templates, even if these sources have AGN-like X-ray luminosities. Preselecting the library on the bases of the source properties allowed us to reach an accuracy σ Δz/(1+z spec ) ∼0.015 with a fraction of outliers of 5.8% for the entire Chandra-COSMOS sample. In addition, we release revised photometric redshifts for the 1735 optical counterparts of the XMM-detected sources over the entire 2 deg 2 of COSMOS. For 248 sources, our updated photometric redshift differs from the previous release by Δz > 0.2. These changes are predominantly due to the inclusion of newly available deep H-band photometry (H AB = 24 mag). We illustrate once again the importance of a spectroscopic training sample and how an assumption about the nature of a source together, with the number and the depth of the available bands, influences the accuracy of the photometric redshifts determined for AGN. These considerations should be kept in mind when defining the observational strategies of upcoming large surveys targeting AGNs, such as eROSITA at X-ray energies and the Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe in the radio band.

  3. COLLIMATION AND SCATTERING OF THE ACTIVE GALACTIC NUCLEUS EMISSION IN THE SOMBRERO GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, R. B.; Steiner, J. E.; Ricci, T. V., E-mail: robertobm@astro.iag.usp.br [Instituto de Astronomia Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, Sao Paulo, SP CEP 05508-090 (Brazil)

    2013-03-10

    We present an analysis of a data cube of the central region of M104, the Sombrero galaxy, obtained with the GMOS-IFU of the Gemini-South telescope, and report the discovery of collimation and scattering of the active galactic nucleus (AGN) emission in the circumnuclear region of this galaxy. Analysis with PCA Tomography and spectral synthesis revealed the existence of collimation and scattering of the AGN featureless continuum and also of a broad component of the H{alpha} emission line. The collimation and scattering of this broad H{alpha} component was also revealed by fitting the [N II] {lambda}{lambda}6548, 6583 and H{alpha} emission lines as a sum of Gaussian functions. The spectral synthesis, together with a V-I image obtained with the Hubble Space Telescope, showed the existence of circumnuclear dust, which may cause the light scattering. We also identify a dusty feature that may be interpreted as a torus/disk structure. The existence of two opposite regions with featureless continuum (P.A. = -18 Degree-Sign {+-} 13 Degree-Sign and P.A. = 162 Degree-Sign {+-} 13 Degree-Sign ) along a direction perpendicular to the torus/disk (P.A. = 72 Degree-Sign {+-} 14 Degree-Sign ) suggests that this structure is approximately edge-on and collimates the AGN emission. The edge-on torus/disk also hides the broad-line region. The proposed scenario is compatible with the unified model and explains why only a weak broad component of the H{alpha} emission line is visible and also why many previous studies detected no broad H{alpha}. The technique used here proved to be an efficient method not only for detecting scattered light, but also for testing the unified model in low-luminosity AGNs.

  4. THE Fe II EMISSION IN ACTIVE GALACTIC NUCLEI: EXCITATION MECHANISMS AND LOCATION OF THE EMITTING REGION

    International Nuclear Information System (INIS)

    Marinello, M.; Rodríguez-Ardila, A.; Garcia-Rissmann, A.; Sigut, T. A. A.; Pradhan, A. K.

    2016-01-01

    We present a study of Fe ii emission in the near-infrared region (NIR) for 25 active galactic nuclei (AGNs) to obtain information about the excitation mechanisms that power it and the location where it is formed. We employ an NIR Fe ii template derived in the literature and find that it successfully reproduces the observed Fe ii spectrum. The Fe ii bump at 9200 Å detected in all objects studied confirms that Lyα fluorescence is always present in AGNs. The correlation found between the flux of the 9200 Å bump, the 1 μm lines, and the optical Fe ii implies that Lyα fluorescence plays an important role in Fe ii production. We determined that at least 18% of the optical Fe ii is due to this process, while collisional excitation dominates the production of the observed Fe ii. The line profiles of Fe ii λ10502, O i λ11287, Ca ii λ8664, and Paβ were compared to gather information about the most likely location where they are emitted. We found that Fe ii, O i and Ca ii have similar widths and are, on average, 30% narrower than Paβ. Assuming that the clouds emitting the lines are virialized, we show that the Fe ii is emitted in a region twice as far from the central source than Paβ. The distance, though, strongly varies: from 8.5 light-days for NGC 4051 to 198.2 light-days for Mrk 509. Our results reinforce the importance of the Fe ii in the NIR to constrain critical parameters that drive its physics and the underlying AGN kinematics, as well as more accurate models aimed at reproducing this complex emission

  5. IRON OPACITY BUMP CHANGES THE STABILITY AND STRUCTURE OF ACCRETION DISKS IN ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yan-Fei [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Davis, Shane W. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Stone, James M. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2016-08-10

    Accretion disks around supermassive black holes have regions where the Rosseland mean opacity can be larger than the electron scattering opacity due to the large number of bound–bound transitions in iron. We study the effects of this iron opacity “bump” on the thermal stability and vertical structure of radiation-pressure-dominated accretion disks, utilizing three-dimensional radiation magnetohydrodynamic (MHD) simulations in the local shearing box approximation. The simulations self-consistently calculate the heating due to MHD turbulence caused by magneto-rotational instability and radiative cooling by using the radiative transfer module based on a variable Eddington tensor in Athena. For a 5 × 10{sup 8} solar mass black hole with ∼3% of the Eddington luminosity, a model including the iron opacity bump maintains its structure for more than 10 thermal times without showing significant signs of thermal runaway. In contrast, if only electron scattering and free–free opacity are included as in the standard thin disk model, the disk collapses on the thermal timescale. The difference is caused by a combination of (1) an anti-correlation between the total optical depth and the midplane pressure, and (2) enhanced vertical advective energy transport. These results suggest that the iron opacity bump may have a strong impact on the stability and structure of active galactic nucleus (AGN) accretion disks, and may contribute to a dependence of AGN properties on metallicity. Since this opacity is relevant primarily in UV emitting regions of the flow, it may help to explain discrepancies between observation and theory that are unique to AGNs.

  6. X-Ray Emission from Active Galactic Nuclei with Intermediate-Mass Black Holes

    Science.gov (United States)

    Dewangan, G. C.; Mathur, S.; Griffiths, R. E.; Rao, A. R.

    2008-12-01

    We present a systematic X-ray study of eight active galactic nuclei (AGNs) with intermediate-mass black holes (MBH ~ 8-95 × 104 M⊙) based on 12 XMM-Newton observations. The sample includes the two prototype AGNs in this class—NGC 4395 and POX 52 and six other AGNs discovered with the Sloan Digitized Sky Survey. These AGNs show some of the strongest X-ray variability, with the normalized excess variances being the largest and the power density break timescales being the shortest observed among radio-quiet AGNs. The excess-variance-luminosity correlation appears to depend on both the BH mass and the Eddington luminosity ratio. The break timescale-black hole mass relations for AGN with IMBHs are consistent with that observed for massive AGNs. We find that the FWHM of the Hβ/Hα line is uncorrelated with the BH mass, but shows strong anticorrelation with the Eddington luminosity ratio. Four AGNs show clear evidence for soft X-ray excess emission (kTin ~ 150-200 eV). X-ray spectra of three other AGNs are consistent with the presence of the soft excess emission. NGC 4395 with lowest L/LEdd lacks the soft excess emission. Evidently small black mass is not the primary driver of strong soft X-ray excess emission from AGNs. The X-ray spectral properties and optical-to-X-ray spectral energy distributions of these AGNs are similar to those of Seyfert 1 galaxies. The observed X-ray/UV properties of AGNs with IMBHs are consistent with these AGNs being low-mass extensions of more massive AGNs, those with high Eddington luminosity ratio looking more like narrow-line Seyfert 1 s and those with low L/LEdd looking more like broad-line Seyfert 1 galaxies.

  7. THE LOW-LUMINOSITY END OF THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Bentz, Misty C.; Denney, Kelly D.; Vestergaard, Marianne; Grier, Catherine J.; Peterson, Bradley M.; De Rosa, Gisella; Pogge, Richard W.; Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Li Weidong; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Stern, Daniel; Treu, Tommaso; Woo, Jong-Hak

    2013-01-01

    We present an updated and revised analysis of the relationship between the Hβ broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the Hβ time lag, which is assumed to yield the average Hβ BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R BLR -L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of α= 0.533 +0.035 -0.033 , consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19 ± 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R BLR -L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.

  8. THE LOW-LUMINOSITY END OF THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Bentz, Misty C. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Denney, Kelly D.; Vestergaard, Marianne [Dark Cosmology Center, Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Grier, Catherine J.; Peterson, Bradley M.; De Rosa, Gisella; Pogge, Richard W. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Bennert, Vardha N. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States); Canalizo, Gabriela [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Filippenko, Alexei V.; Li Weidong [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Gates, Elinor L. [University of California Observatories/Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Peyton Hall - Ivy Lane, Princeton, NJ 08544 (United States); Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Treu, Tommaso [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Woo, Jong-Hak, E-mail: bentz@chara.gsu.edu [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of)

    2013-04-20

    We present an updated and revised analysis of the relationship between the H{beta} broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the H{beta} time lag, which is assumed to yield the average H{beta} BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R{sub BLR}-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of {alpha}= 0.533{sup +0.035}{sub -0.033}, consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19 {+-} 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R{sub BLR}-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.

  9. NO CLEAR SUBMILLIMETER SIGNATURE OF SUPPRESSED STAR FORMATION AMONG X-RAY LUMINOUS ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, C. M.; Alexander, D. M.; Mullaney, J. R.; Del Moro, A.; Rovilos, E. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Altieri, B.; Coia, D. [Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Canada, E-28691 Madrid (Spain); Charmandaris, V. [Department of Physics and Institute of Theoretical and Computation Physics, University of Crete, 71003 Heraklion (Greece); Daddi, E.; Le Floc' h, E.; Leiton, R. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d Astrophysique, CEA-Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France); Dannerbauer, H. [Insitut fuer Astrophysik, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180 Wien (Austria); Dasyra, K. [Observatoire de Paris, LERMA (CNRS:UMR8112), 61 Av. de l' Observatoire, F-75014 Paris (France); Dickinson, M.; Kartaltepe, J. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Hickox, R. C. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Ivison, R. J. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Magnelli, B.; Popesso, P.; Rosario, D. [Max-Planck-Institut fuer Extraterrestrische Physik (MPE), Postfach 1312, D-85741 Garching (Germany); and others

    2012-11-20

    Many theoretical models require powerful active galactic nuclei (AGNs) to suppress star formation in distant galaxies and reproduce the observed properties of today's massive galaxies. A recent study based on Herschel-SPIRE submillimeter observations claimed to provide direct support for this picture, reporting a significant decrease in the mean star formation rates (SFRs) of the most luminous AGNs (L{sub X} >10{sup 44} erg s{sup -1}) at z Almost-Equal-To 1-3 in the Chandra Deep Field-North (CDF-N). In this Letter, we extend these results using Herschel-SPIRE 250 {mu}m data in the COSMOS and Chandra Deep Field-South fields to achieve an order-of-magnitude improvement in the number of sources at L{sub X} >10{sup 44} erg s{sup -1}. On the basis of our analysis, we find no strong evidence for suppressed star formation in L{sub X} >10{sup 44} erg s{sup -1} AGNs at z Almost-Equal-To 1-3. The mean SFRs of the AGNs are constant over the broad X-ray luminosity range of L{sub X} Almost-Equal-To 10{sup 43}-10{sup 45} erg s{sup -1} (with mean SFRs consistent with typical star-forming galaxies at z Almost-Equal-To 2; (SFRs) Almost-Equal-To 100-200 M{sub Sun} yr{sup -1}). We suggest that the previous CDF-N results were likely due to low number statistics. We discuss our results in the context of current theoretical models.

  10. On the contribution of active galactic nuclei to the high-redshift metagalactic ionizing background

    Science.gov (United States)

    D'Aloisio, Anson; Upton Sanderbeck, Phoebe R.; McQuinn, Matthew; Trac, Hy; Shapiro, Paul R.

    2017-07-01

    Motivated by the claimed detection of a large population of faint active galactic nuclei (AGNs) at high redshift, recent studies have proposed models in which AGNs contribute significantly to the z > 4 H I ionizing background. In some models, AGNs are even the chief sources of reionization. If proved true, these models would make necessary a complete revision to the standard view that galaxies dominated the high-redshift ionizing background. It has been suggested that AGN-dominated models can better account for two recent observations that appear to be in conflict with the standard view: (1) large opacity variations in the z ˜ 5.5 H I Ly α forest, and (2) slow evolution in the mean opacity of the He II Ly α forest. Large spatial fluctuations in the ionizing background from the brightness and rarity of AGNs may account for the former, while the earlier onset of He II reionization in these models may account for the latter. Here we show that models in which AGN emissions source ≳50 per cent of the ionizing background generally provide a better fit to the observed H I Ly α forest opacity variations compared to standard galaxy-dominated models. However, we argue that these AGN-dominated models are in tension with constraints on the thermal history of the intergalactic medium (IGM). Under standard assumptions about the spectra of AGNs, we show that the earlier onset of He II reionization heats up the IGM well above recent temperature measurements. We further argue that the slower evolution of the mean opacity of the He II Ly α forest relative to simulations may reflect deficiencies in current simulations rather than favour AGN-dominated models as has been suggested.

  11. MEASURING X-RAY VARIABILITY IN FAINT/SPARSELY SAMPLED ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Allevato, V. [Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland); Paolillo, M. [Department of Physical Sciences, University Federico II, via Cinthia 6, I-80126 Naples (Italy); Papadakis, I. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, 71003 Heraklion (Greece); Pinto, C. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584-CA Utrecht (Netherlands)

    2013-07-01

    We study the statistical properties of the normalized excess variance of variability process characterized by a ''red-noise'' power spectral density (PSD), as in the case of active galactic nuclei (AGNs). We perform Monte Carlo simulations of light curves, assuming both a continuous and a sparse sampling pattern and various signal-to-noise ratios (S/Ns). We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled light curves. The bias depends on the PSD slope and on the sampling pattern, but not on the S/N. We provide a simple formula to account for the bias, which yields unbiased estimates with an accuracy better than 15%. We show that the normalized excess variance estimates based on single light curves (especially for sparse sampling and S/N < 3) are highly uncertain (even if corrected for bias) and we propose instead the use of an ''ensemble estimate'', based on multiple light curves of the same object, or on the use of light curves of many objects. These estimates have symmetric distributions, known errors, and can also be corrected for biases. We use our results to estimate the ability to measure the intrinsic source variability in current data, and show that they could also be useful in the planning of the observing strategy of future surveys such as those provided by X-ray missions studying distant and/or faint AGN populations and, more in general, in the estimation of the variability amplitude of sources that will result from future surveys such as Pan-STARRS and LSST.

  12. GPU-BASED MONTE CARLO DUST RADIATIVE TRANSFER SCHEME APPLIED TO ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Heymann, Frank; Siebenmorgen, Ralf

    2012-01-01

    A three-dimensional parallel Monte Carlo (MC) dust radiative transfer code is presented. To overcome the huge computing-time requirements of MC treatments, the computational power of vectorized hardware is used, utilizing either multi-core computer power or graphics processing units. The approach is a self-consistent way to solve the radiative transfer equation in arbitrary dust configurations. The code calculates the equilibrium temperatures of two populations of large grains and stochastic heated polycyclic aromatic hydrocarbons. Anisotropic scattering is treated applying the Heney-Greenstein phase function. The spectral energy distribution (SED) of the object is derived at low spatial resolution by a photon counting procedure and at high spatial resolution by a vectorized ray tracer. The latter allows computation of high signal-to-noise images of the objects at any frequencies and arbitrary viewing angles. We test the robustness of our approach against other radiative transfer codes. The SED and dust temperatures of one- and two-dimensional benchmarks are reproduced at high precision. The parallelization capability of various MC algorithms is analyzed and included in our treatment. We utilize the Lucy algorithm for the optical thin case where the Poisson noise is high, the iteration-free Bjorkman and Wood method to reduce the calculation time, and the Fleck and Canfield diffusion approximation for extreme optical thick cells. The code is applied to model the appearance of active galactic nuclei (AGNs) at optical and infrared wavelengths. The AGN torus is clumpy and includes fluffy composite grains of various sizes made up of silicates and carbon. The dependence of the SED on the number of clumps in the torus and the viewing angle is studied. The appearance of the 10 μm silicate features in absorption or emission is discussed. The SED of the radio-loud quasar 3C 249.1 is fit by the AGN model and a cirrus component to account for the far-infrared emission.

  13. Spatially Resolved Imaging and Spectroscopy of Candidate Dual Active Galactic Nuclei

    Science.gov (United States)

    McGurk, R. C.; Max, C. E.; Medling, A. M.; Shields, G. A.; Comerford, J. M.

    2015-09-01

    When galaxies merge, both central supermassive black holes are immersed in a dense and chaotic environment. If there is sufficient gas in the nuclear regions, one expects to see close pairs of active galactic nuclei (AGNs), or dual AGNs, in a fraction of galaxy mergers. However, finding them remains a challenge. The presence of double-peaked [O iii] emission lines has been proposed as a technique to select dual AGNs efficiently. We studied a sample of double-peaked narrow [O iii] emitting AGNs from Sloan Digital Sky Survey (SDSS) DR7. By obtaining new and archival high spatial resolution images taken with the Keck II Laser Guide Star Adaptive Optics system and the near-infrared camera NIRC2, we show that 30% of 140 double-peaked [O iii] emission line SDSS AGNs have two spatial components within a 3″ radius. However, spatially resolved spectroscopy or X-ray observations are needed to confirm these galaxy pairs as systems containing two AGNs. We followed up three spatially double candidate dual AGNs with integral field spectroscopy from Keck OSIRIS and 10 candidates with long-slit spectroscopy from the Shane Kast Double Spectrograph at Lick Observatory. We find that the double-peaked emission lines in our sample of 12 candidates are caused by: one dual AGN (SDSS J114642.47+511029.6), one confirmed outflow and four likely outflows, two pairs of star-forming galaxies, one candidate indeterminate due to sky line interference, and three AGNs with spatially coincident double [O iii] peaks, likely due to unresolved complex narrow line kinematics, outflows, binary AGN, or small-scale jets.

  14. SPATIALLY RESOLVED IMAGING AND SPECTROSCOPY OF CANDIDATE DUAL ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    McGurk, R. C.; Max, C. E. [Astronomy Department and UCO-Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Medling, A. M. [Research School of Astronomy and Astrophysics, Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Shields, G. A. [Laguna Falls Institute for Astrophysics, Austin, TX 78746 (United States); Comerford, J. M., E-mail: rosalie.mcgurk@gmail.com, E-mail: max@ucolick.org, E-mail: anne.medling@anu.edu.au, E-mail: shields@lfastro.org, E-mail: julie.comerford@colorado.edu [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2015-09-20

    When galaxies merge, both central supermassive black holes are immersed in a dense and chaotic environment. If there is sufficient gas in the nuclear regions, one expects to see close pairs of active galactic nuclei (AGNs), or dual AGNs, in a fraction of galaxy mergers. However, finding them remains a challenge. The presence of double-peaked [O iii] emission lines has been proposed as a technique to select dual AGNs efficiently. We studied a sample of double-peaked narrow [O iii] emitting AGNs from Sloan Digital Sky Survey (SDSS) DR7. By obtaining new and archival high spatial resolution images taken with the Keck II Laser Guide Star Adaptive Optics system and the near-infrared camera NIRC2, we show that 30% of 140 double-peaked [O iii] emission line SDSS AGNs have two spatial components within a 3″ radius. However, spatially resolved spectroscopy or X-ray observations are needed to confirm these galaxy pairs as systems containing two AGNs. We followed up three spatially double candidate dual AGNs with integral field spectroscopy from Keck OSIRIS and 10 candidates with long-slit spectroscopy from the Shane Kast Double Spectrograph at Lick Observatory. We find that the double-peaked emission lines in our sample of 12 candidates are caused by: one dual AGN (SDSS J114642.47+511029.6), one confirmed outflow and four likely outflows, two pairs of star-forming galaxies, one candidate indeterminate due to sky line interference, and three AGNs with spatially coincident double [O iii] peaks, likely due to unresolved complex narrow line kinematics, outflows, binary AGN, or small-scale jets.

  15. SPATIALLY RESOLVED IMAGING AND SPECTROSCOPY OF CANDIDATE DUAL ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    McGurk, R. C.; Max, C. E.; Medling, A. M.; Shields, G. A.; Comerford, J. M.

    2015-01-01

    When galaxies merge, both central supermassive black holes are immersed in a dense and chaotic environment. If there is sufficient gas in the nuclear regions, one expects to see close pairs of active galactic nuclei (AGNs), or dual AGNs, in a fraction of galaxy mergers. However, finding them remains a challenge. The presence of double-peaked [O iii] emission lines has been proposed as a technique to select dual AGNs efficiently. We studied a sample of double-peaked narrow [O iii] emitting AGNs from Sloan Digital Sky Survey (SDSS) DR7. By obtaining new and archival high spatial resolution images taken with the Keck II Laser Guide Star Adaptive Optics system and the near-infrared camera NIRC2, we show that 30% of 140 double-peaked [O iii] emission line SDSS AGNs have two spatial components within a 3″ radius. However, spatially resolved spectroscopy or X-ray observations are needed to confirm these galaxy pairs as systems containing two AGNs. We followed up three spatially double candidate dual AGNs with integral field spectroscopy from Keck OSIRIS and 10 candidates with long-slit spectroscopy from the Shane Kast Double Spectrograph at Lick Observatory. We find that the double-peaked emission lines in our sample of 12 candidates are caused by: one dual AGN (SDSS J114642.47+511029.6), one confirmed outflow and four likely outflows, two pairs of star-forming galaxies, one candidate indeterminate due to sky line interference, and three AGNs with spatially coincident double [O iii] peaks, likely due to unresolved complex narrow line kinematics, outflows, binary AGN, or small-scale jets

  16. COLLIMATION AND SCATTERING OF THE ACTIVE GALACTIC NUCLEUS EMISSION IN THE SOMBRERO GALAXY

    International Nuclear Information System (INIS)

    Menezes, R. B.; Steiner, J. E.; Ricci, T. V.

    2013-01-01

    We present an analysis of a data cube of the central region of M104, the Sombrero galaxy, obtained with the GMOS-IFU of the Gemini-South telescope, and report the discovery of collimation and scattering of the active galactic nucleus (AGN) emission in the circumnuclear region of this galaxy. Analysis with PCA Tomography and spectral synthesis revealed the existence of collimation and scattering of the AGN featureless continuum and also of a broad component of the Hα emission line. The collimation and scattering of this broad Hα component was also revealed by fitting the [N II] λλ6548, 6583 and Hα emission lines as a sum of Gaussian functions. The spectral synthesis, together with a V-I image obtained with the Hubble Space Telescope, showed the existence of circumnuclear dust, which may cause the light scattering. We also identify a dusty feature that may be interpreted as a torus/disk structure. The existence of two opposite regions with featureless continuum (P.A. = –18° ± 13° and P.A. = 162° ± 13°) along a direction perpendicular to the torus/disk (P.A. = 72° ± 14°) suggests that this structure is approximately edge-on and collimates the AGN emission. The edge-on torus/disk also hides the broad-line region. The proposed scenario is compatible with the unified model and explains why only a weak broad component of the Hα emission line is visible and also why many previous studies detected no broad Hα. The technique used here proved to be an efficient method not only for detecting scattered light, but also for testing the unified model in low-luminosity AGNs.

  17. Local Swift-BAT active galactic nuclei prefer circumnuclear star formation

    Science.gov (United States)

    Lutz, D.; Shimizu, T.; Davies, R. I.; Herrera-Camus, R.; Sturm, E.; Tacconi, L. J.; Veilleux, S.

    2018-01-01

    We use Herschel data to analyze the size of the far-infrared 70 μm emission for z BAT selected active galactic nuclei (AGN), and 515 comparison galaxies that are not detected by BAT. For modest far-infrared luminosities 8.5 BAT hosts that is only half that of comparison galaxies of same far-infrared luminosity. The result mostly reflects a more compact distribution of star formation (and hence gas) in the AGN hosts, but compact AGN heated dust may contribute in some extremely AGN dominated systems. Our findings are in support of an AGN-host coevolution where accretion onto the central black hole and star formation are fed from the same gas reservoir, with more efficient black hole feeding if that reservoir is more concentrated. The significant scatter in the far-infrared sizes emphasizes that we are mostly probing spatial scales much larger than those of actual accretion, and that rapid accretion variations can smear the distinction between the AGN and comparison categories. Large samples are hence needed to detect structural differences that favor feeding of the black hole. No size difference between AGN host and comparison galaxies is observed at higher far-infrared luminosities log(LFIR [L⊙]) > 10.5 (star formation rates ≳6 M⊙ yr-1), possibly because these are typically reached in more compact regions. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A9

  18. The case for inflow of the broad-line region of active galactic nuclei

    Science.gov (United States)

    Gaskell, C. Martin; Goosmann, René W.

    2016-02-01

    The high-ionization lines of the broad-line region (BLR) of thermal active galactic nuclei (AGNs) show blueshifts of a few hundred km/s to several thousand km/sec with respect to the low-ionization lines. This has long been thought to be due to the high-ionization lines of the BLR arising in a wind of which the far side of the outflow is blocked from our view by the accretion disc. Evidence for and against the disc-wind model is discussed. The biggest problem for the model is that velocity-resolved reverberation mapping repeatedly fails to show the expected kinematic signature of outflow of the BLR. The disc-wind model also cannot readily reproduce the red side of the line profiles of high-ionization lines. The rapidly falling density in an outflow makes it difficult to obtain high equivalent widths. We point out a number of major problems with associating the BLR with the outflows producing broad absorption lines. An explanation which avoids all these problems and satisfies the constraints of both the line profiles and velocity-resolved reverberation-mapping is a model in which the blueshifting is due to scattering off material spiraling inwards with an inflow velocity of half the velocity of the blueshifting. We discuss how recent reverberation mapping results are consistent with the scattering-plus-inflow model but do not support a disc-wind model. We propose that the anti-correlation of the apparent redshifting of Hβ with the blueshifting of C iv is a consequence of contamination of the red wings of Hβ by the broad wings of [O iii].

  19. The energetics of relativistic jets in active galactic nuclei with various kinetic powers

    Science.gov (United States)

    Musoke, Gibwa Rebecca; Young, Andrew; Molnar, Sandor; Birkinshaw, Mark

    2018-01-01

    Numerical simulations are an important tool in understanding the physical processes behind relativistic jets in active galactic nuclei. In such simulations different combinations of intrinsic jet parameters can be used to obtain the same jet kinetic powers. We present a numerical investigation of the effects of varying the jet power on the dynamic and energetic characteristics of the jets for two kinetic power regimes; in the first regime we change the jet density whilst maintaining a fixed velocity, in the second the jet density is held constant while the velocity is varied. We conduct 2D axisymmetric hydrodynamic simulations of bipolar jets propagating through an isothermal cluster atmosphere using the FLASH MHD code in pure hydrodynamics mode. The jets are simulated with kinetic powers ranging between 1045 and 1046 erg/s and internal Mach numbers ranging from 5.6 to 21.5.As the jets begin to propagate into the intracluster medium (ICM), the injected jet energy is converted into the thermal, kinetic and gravitational potential energy components of the jet cocoon and ICM. We explore the temporal evolution of the partitioning of the injected jet energy into the cocoon and the ICM and quantify the importance of entrainment process on the energy partitioning. We investigate the fraction of injected energy transferred to the thermal energy component of the jet-ICM system in the context of heating the cluster environments, noting that the jets simulated display peak thermalisation efficiencies of least 65% and a marked dependence on the jet density. We compare the efficiencies of the energy partitioning between the cocoon and ICM for the two kinetic power regimes and discuss the resulting efficiency-power scaling relations of each regime.

  20. ACTIVE GALACTIC NUCLEI IN GROUPS AND CLUSTERS OF GALAXIES: DETECTION AND HOST MORPHOLOGY

    International Nuclear Information System (INIS)

    Arnold, Timothy J.; Martini, Paul; Mulchaey, John S.; Berti, Angela; Jeltema, Tesla E.

    2009-01-01

    The incidence and properties of active galactic nuclei (AGNs) in the field, groups, and clusters can provide new information about how these objects are triggered and fueled, similar to how these environments have been employed to study galaxy evolution. We have obtained new XMM-Newton observations of seven X-ray selected groups and poor clusters with 0.02 -1 ). We find that the X-ray selected AGN fraction increases from f A (L X ≥ 10 41 ; M R ≤ M* R + 1) = 0.047 +0.023 -0.016 in clusters to 0.091 +0.049 -0.034 for the groups (85% significance), or a factor of 2, for AGN above an 0.3-8 keV X-ray luminosity of 10 41 ergs -1 hosted by galaxies more luminous than M* R + 1. The trend is similar, although less significant, for a lower-luminosity host threshold of M R = -20 mag. For many of the groups in the sample, we have also identified AGN via standard emission-line diagnostics and find that these AGNs are nearly disjoint from the X-ray selected AGN. Because there are substantial differences in the morphological mix of galaxies between groups and clusters, we have also measured the AGN fraction for early-type galaxies alone to determine if the differences are directly due to environment, or indirectly due to the change in the morphological mix. We find that the AGN fraction in early-type galaxies is also lower in clusters f A,n≥2.5 (L X ≥ 10 41 ; M R ≤ M* R + 1) = 0.048 +0.028 -0.019 compared to 0.119 +0.064 -0.044 for the groups (92% significance), a result consistent with the hypothesis that the change in AGN fraction is directly connected to environment.

  1. ACTIVE GALACTIC NUCLEUS FEEDBACK AND ENTROPY INJECTION IN GALAXY CLUSTER CORES

    International Nuclear Information System (INIS)

    Chaudhuri, Anya; Majumdar, Subhabrata; Nath, Biman B.

    2013-01-01

    We make the first estimate of non-gravitational energy profiles in galaxy cluster cores (and beyond) based on observational data. Comparing the observed entropy profiles within r 500 , from the Representative XMM-Newton Cluster Structure Survey to simulated base entropy profiles without feedback from both adaptive mesh refinement (AMR) and smoothed particle hydrodynamic (SPH) non-radiative simulations, we estimate the amount of additional non-gravitational energy, E ICM , contained in the intracluster medium (ICM), as well as the total energy feedback, E Feedback , from active galactic nuclei (AGNs; the central AGNs in most cases) into the clusters. The total feedback energy scales with the mean spectroscopic temperature as E Feedback ∝T sp 2.52±0.08 and E Feedback ∝T sp 2.17±0.11 for the SPH and AMR baseline profiles. The mean non-gravitational energy per particle within r 500 remaining in the ICM after energy lost during cooling is ε ICM = 2.8 ± 0.8 keV for the SPH theoretical relation and ε ICM = 1.7 ± 0.9 keV for the AMR theoretical relation. We use the NRAO/VLA Sky Survey source catalog to determine the radio luminosity, L R , at 1.4 GHz of the central source(s) of our sample. For T sp > 3 keV, the E Feedback correlates with L R , although with different normalization for cool-core and non-cool-core clusters. We show that AGNs could provide a significant portion of the feedback

  2. THE Fe II EMISSION IN ACTIVE GALACTIC NUCLEI: EXCITATION MECHANISMS AND LOCATION OF THE EMITTING REGION

    Energy Technology Data Exchange (ETDEWEB)

    Marinello, M. [Universidade Federal de Itajubá, Rua Doutor Pereira Cabral 1303, 37500-903, Itajubá, MG (Brazil); Rodríguez-Ardila, A.; Garcia-Rissmann, A. [Laboratório Nacional de Astrofísica, Rua Estados Unidos 154, Itajubá, MG, 37504-364 (Brazil); Sigut, T. A. A. [The University of Western Ontario, London, ON N6A 3K7 (Canada); Pradhan, A. K., E-mail: murilo.marinello@gmail.com [McPherson Laboratory, The Ohio State University, 140 W. 18th Ave., Columbus, OH 43210-1173 (United States)

    2016-04-01

    We present a study of Fe ii emission in the near-infrared region (NIR) for 25 active galactic nuclei (AGNs) to obtain information about the excitation mechanisms that power it and the location where it is formed. We employ an NIR Fe ii template derived in the literature and find that it successfully reproduces the observed Fe ii spectrum. The Fe ii bump at 9200 Å detected in all objects studied confirms that Lyα fluorescence is always present in AGNs. The correlation found between the flux of the 9200 Å bump, the 1 μm lines, and the optical Fe ii implies that Lyα fluorescence plays an important role in Fe ii production. We determined that at least 18% of the optical Fe ii is due to this process, while collisional excitation dominates the production of the observed Fe ii. The line profiles of Fe ii λ10502, O i λ11287, Ca ii λ8664, and Paβ were compared to gather information about the most likely location where they are emitted. We found that Fe ii, O i and Ca ii have similar widths and are, on average, 30% narrower than Paβ. Assuming that the clouds emitting the lines are virialized, we show that the Fe ii is emitted in a region twice as far from the central source than Paβ. The distance, though, strongly varies: from 8.5 light-days for NGC 4051 to 198.2 light-days for Mrk 509. Our results reinforce the importance of the Fe ii in the NIR to constrain critical parameters that drive its physics and the underlying AGN kinematics, as well as more accurate models aimed at reproducing this complex emission.

  3. RefleX: X-ray absorption and reflection in active galactic nuclei for arbitrary geometries

    Science.gov (United States)

    Paltani, S.; Ricci, C.

    2017-11-01

    Reprocessed X-ray radiation carries important information about the structure and physical characteristics of the material surrounding the supermassive black hole (SMBH) in active galactic nuclei (AGN). We report here on a newly developed simulation platform, RefleX, which allows to reproduce absorption and reflection by quasi-arbitrary geometries. We show here the reliability of our approach by comparing the results of our simulations with existing spectral models such as pexrav, MYTorus and BNTorus. RefleX implements both Compton scattering on free electrons and Rayleigh scattering and Compton scattering on bound electrons. We show the effect of bound-electron corrections on a torus geometry simulated like in MYTorus. We release with this paper the RefleX executable, as well as RXTorus, a model that assumes absorption and reflection from a torus with a varying ratio of the minor to major axis of the torus. To allow major flexibility RXTorus is also distributed in three components: absorbed primary emission, scattered radiation and fluorescent lines. RXTorus is provided for different values of the abundance, and with (atomic configuration) or without (free-electron configuration) taking into account Rayleigh scattering and bound electrons. We apply the RXTorus model in both configurations on the XMM-Newton and NuSTAR spectrum of the Compton-thick AGN NGC 424 and find that the models are able to reproduce very well the observations, but that the assumption on the bound or free state of the electrons has significant consequences on the fit parameters. RefleX executable, user manual and example models are available at http://www.astro.unige.ch/reflex. A copy of the RefleX executable is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/607/A31

  4. Dust inflated accretion disc as the origin of the broad line region in active galactic nuclei

    Science.gov (United States)

    Baskin, Alexei; Laor, Ari

    2018-02-01

    The broad line region (BLR) in active galactic nuclei (AGNs) is composed of dense gas (˜1011 cm-3) on sub-pc scale, which absorbs about 30 per cent of the ionizing continuum. The outer size of the BLR is likely set by dust sublimation, and its density by the incident radiation pressure compression (RPC). But, what is the origin of this gas, and what sets its covering factor (CF)? Czerny & Hryniewicz (2011) suggested that the BLR is a failed dusty wind from the outer accretion disc. We explore the expected dust properties, and the implied BLR structure. We find that graphite grains sublimate only at T ≃ 2000 K at the predicted density of ˜1011 cm-3, and therefore large graphite grains (≥0.3 μm) survive down to the observed size of the BLR, RBLR. The dust opacity in the accretion disc atmosphere is ˜50 times larger than previously assumed, and leads to an inflated torus-like structure, with a predicted peak height at RBLR. The illuminated surface of this torus-like structure is a natural place for the BLR. The BLR CF is mostly set by the gas metallicity, the radiative accretion efficiency, a dynamic configuration and ablation by the incident optical-UV continuum. This model predicts that the BLR should extend inwards of RBLR to the disc radius where the surface temperature is ≃2000 K, which occurs at Rin ≃ 0.18RBLR. The value of Rin can be tested by reverberation mapping of the higher ionization lines, predicted by RPC to peak well inside RBLR. The dust inflated disc scenario can also be tested based on the predicted response of RBLR and the CF to changes in the AGN luminosity and accretion rate.

  5. Parsec-scale Faraday rotation and polarization of 20 active galactic nuclei jets

    Science.gov (United States)

    Kravchenko, E. V.; Kovalev, Y. Y.; Sokolovsky, K. V.

    2017-05-01

    We perform polarimetry analysis of 20 active galactic nuclei jets using the very long baseline array at 1.4, 1.6, 2.2, 2.4, 4.6, 5.0, 8.1, 8.4 and 15.4 GHz. The study allowed us to investigate linearly polarized properties of the jets at parsec scales: distribution of the Faraday rotation measure (RM) and fractional polarization along the jets, Faraday effects and structure of Faraday-corrected polarization images. Wavelength dependence of the fractional polarization and polarization angle is consistent with external Faraday rotation, while some sources show internal rotation. The RM changes along the jets, systematically increasing its value towards synchrotron self-absorbed cores at shorter wavelengths. The highest core RM reaches 16 900 rad m-2 in the source rest frame for the quasar 0952+179, suggesting the presence of highly magnetized, dense media in these regions. The typical RM of transparent jet regions has values of an order of a hundred rad m-2. Significant transverse RM gradients are observed in seven sources. The magnetic field in the Faraday screen has no preferred orientation, and is observed to be random or regular from source to source. Half of the sources show evidence for the helical magnetic fields in their rotating magneto-ionic media. At the same time jets themselves contain large-scale, ordered magnetic fields and tend to align its direction with the jet flow. The observed variety of polarized signatures can be explained by a model of spine-sheath jet structure.

  6. From starburst to quiescence: testing active galactic nucleus feedback in rapidly quenching post-starburst galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Yesuf, Hassen M.; Faber, S. M.; Trump, Jonathan R.; Koo, David C.; Fang, Jerome J.; Liu, F. S. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Wild, Vivienne [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, KY16 9SS (United Kingdom); Hayward, Christopher C. [Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany)

    2014-09-10

    Post-starbursts are galaxies in transition from the blue cloud to the red sequence. Although they are rare today, integrated over time they may be an important pathway to the red sequence. This work uses Sloan Digital Sky Survey, the Galaxy Evolution Explorer, and Wide-field Infrared Survey Explorer observations to identify the evolutionary sequence from starbursts to fully quenched post-starbursts (QPSBs) in the narrow mass range log M(M {sub ☉}) = 10.3-10.7, and identifies 'transiting' post-starbursts (TPSBs) which are intermediate between these two populations. In this mass range, ∼0.3% of galaxies are starbursts, ∼0.1% are QPSBs, and ∼0.5% are the transiting types in between. The TPSBs have stellar properties that are predicted for fast-quenching starbursts and morphological characteristics that are already typical of early-type galaxies. The active galactic nucleus (AGN) fraction, as estimated from optical line ratios, of these post-starbursts is about three times higher (≳ 36% ± 8%) than that of normal star forming galaxies of the same mass, but there is a significant delay between the starburst phase and the peak of nuclear optical AGN activity (median age difference of ≳ 200 ± 100 Myr), in agreement with previous studies. The time delay is inferred by comparing the broadband near-NUV-to-optical photometry with stellar population synthesis models. We also find that starbursts and post-starbursts are significantly more dust obscured than normal star forming galaxies in the same mass range. About 20% of the starbursts and 15% of the TPSBs can be classified as 'dust-obscured galaxies' (DOGs), with a near-UV-to-mid-IR flux ratio of ≳ 900, while only 0.8% of normal galaxies are DOGs. The time delay between the starburst phase and AGN activity suggests that AGNs do not play a primary role in the original quenching of starbursts but may be responsible for quenching later low-level star formation by removing gas and dust during

  7. POLYCYCLIC AROMATIC HYDROCARBON AND EMISSION LINE RATIOS IN ACTIVE GALACTIC NUCLEI AND STARBURST GALAXIES

    International Nuclear Information System (INIS)

    Sales, Dinalva A.; Pastoriza, M. G.; Riffel, R.

    2010-01-01

    We study the polycyclic aromatic hydrocarbon (PAH) bands, ionic emission lines, and mid-infrared continuum properties in a sample of 171 emission line galaxies taken from the literature plus 15 new active galactic nucleus (AGN) Spitzer spectra. We normalize the spectra at λ = 23 μm and grouped them according to the type of nuclear activity. The continuum shape steeply rises for longer wavelengths and can be fitted with a warm blackbody distribution of T ∼ 150-300 K. The brightest PAH spectral bands (6.2, 7.7, 8.6, 11.3, and 12.7 μm) and the forbidden emission lines of [Si II] 34.8 μm, [Ar II] 6.9 μm, [S III] 18.7 and 33.4 μm were detected in all the starbursts and in ∼80% of the Seyfert 2. Taking under consideration only the PAH bands at 7.7 μm, 11.3 μm, and 12.7 μm, we find that they are present in ∼80% of the Seyfert 1, while only half of this type of activity show the 6.2 μm and 8.6 μm PAH bands. The observed intensity ratios for neutral and ionized PAHs (6.2 μm/7.7 μm x 11.3 μm/7.7 μm) were compared to theoretical intensity ratios, showing that AGNs have higher ionization fraction and larger PAH molecules (≥180 carbon atoms) than SB galaxies. The ratio between the ionized (7.7 μm) and the neutral PAH bands (8.6 μm and 11.3 μm) are distributed over different ranges for AGNs and SB galaxies, suggesting that these ratios could depend on the ionization fraction, as well as on the hardness of the radiation field. The ratio between the 7.7 μm and 11.3 μm bands is nearly constant with the increase of [Ne III]15.5 μm/[Ne II] 12.8 μm, indicating that the fraction of ionized to neutral PAH bands does not depend on the hardness of the radiation field. The equivalent width of both PAH features show the same dependence (strongly decreasing) with [Ne III]/[Ne II], suggesting that the PAH molecules, emitting either ionized (7.7 μm) or neutral (11.3 μm) bands, may be destroyed with the increase of the hardness of the radiation field.

  8. Synthesis and thermal conductivity of type II silicon clathrates

    Science.gov (United States)

    Beekman, M.; Nolas, G. S.

    2006-08-01

    We have synthesized and characterized polycrystalline Na 1Si 136 and Na 8Si 136, compounds possessing the type II clathrate hydrate crystal structure. Resistivity measurements from 10 to 300 K indicate very large resistivities in this temperature range, with activated temperature dependences indicative of relatively large band gap semiconductors. The thermal conductivity is very low; two orders-of-magnitude lower than that of diamond-structure silicon at room temperature. The thermal conductivity of Na 8Si 136 displays a temperature dependence that is atypical of crystalline solids and more indicative of amorphous materials. This work is part of a continuing effort to explore the many different compositions and structure types of clathrates, a class of materials that continues to be of interest for scientific and technological applications.

  9. Evidence for topological type-II Weyl semimetal WTe2

    KAUST Repository

    Li, Peng; Wen, Yan; He, Xin; Zhang, Qiang; Xia, Chuan; Yu, Zhi-Ming; Yang, Shengyuan A.; Zhu, Zhiyong; Alshareef, Husam N.; Zhang, Xixiang

    2017-01-01

    -called Fermi arcs. Although WTe2 was the first material suggested as a type-II Weyl semimetal, the direct observation of its tilting Weyl cone and Fermi arc has not yet been successful. Here, we show strong evidence that WTe2 is a type-II Weyl semimetal

  10. Evaluation of Type II Fast Packs for Electrostatic Discharge Properties.

    Science.gov (United States)

    1983-08-01

    34 x 8" x 1 3/4") consisting of a reclosable cushioned carrier which mates into an outer fiberboard sleeve. A cushioning insert is used consisting of a... RECLOSABLE CUSHIONED CARRIER TEST LOAD FIGURE 1: Cancel Caddy Pack * CONVOLUTED 4* CUSHIONED I FIGURE 2: Type II Fast Pack (PPP-B-1672) TYPE II FAST PACK

  11. The prevalence of microalbuminuria among patients with type II ...

    African Journals Online (AJOL)

    This cross-sectional community-based study was carried out to determine the prevalence of microalbuminuria among patients with type II diabetes mellitus in a primary care setting, and to study the association between various risk factors and the presence of microalbuminuria. All patients with type II diabetes mellitus who ...

  12. Cartilage turnover reflected by metabolic processing of type II collagen

    DEFF Research Database (Denmark)

    Gudmann, Karoline Natasja Stæhr; Wang, Jianxia; Hoielt, Sabine

    2014-01-01

    The aim of this study was to enable measurement of cartilage formation by a novel biomarker of type II collagen formation. The competitive enzyme-linked immunosorbent assay (ELISA) Pro-C2 was developed and characterized for assessment of the beta splice variant of type II procollagen (PIIBNP). Th...

  13. Preferential type II muscle fiber damage from plyometric exercise.

    Science.gov (United States)

    Macaluso, Filippo; Isaacs, Ashwin W; Myburgh, Kathryn H

    2012-01-01

    Plyometric training has been successfully used in different sporting contexts. Studies that investigated the effect of plyometric training on muscle morphology are limited, and results are controversial with regard to which muscle fiber type is mainly affected. To analyze the skeletal muscle structural and ultrastructural change induced by an acute bout of plyometric exercise to determine which type of muscle fibers is predominantly damaged. Descriptive laboratory study. Research laboratory. Eight healthy, untrained individuals (age = 22 ± 1 years, height = 179.2 ± 6.4 cm, weight = 78.9 ± 5.9 kg). Participants completed an acute bout of plyometric exercise (10 sets of 10 squat-jumps with a 1-minute rest between sets). Blood samples were collected 9 days and immediately before and 6 hours and 1, 2, and 3 days after the acute intervention. Muscle samples were collected 9 days before and 3 days after the exercise intervention. Blood samples were analyzed for creatine kinase activity. Muscle biopsies were analyzed for damage using fluorescent and electron transmission microscopy. Creatine kinase activity peaked 1 day after the exercise bout (529.0 ± 317.8 U/L). Immunofluorescence revealed sarcolemmal damage in 155 of 1616 fibers analyzed. Mainly fast-twitch fibers were damaged. Within subgroups, 7.6% of type I fibers, 10.3% of type IIa fibers, and 14.3% of type IIx fibers were damaged as assessed by losses in dystrophin staining. Similar damage was prevalent in IIx and IIa fibers. Electron microscopy revealed clearly distinguishable moderate and severe sarcomere damage, with damage quantifiably predominant in type II muscle fibers of both the glycolytic and oxidative subtypes (86% and 84%, respectively, versus only 27% of slow-twitch fibers). We provide direct evidence that a single bout of plyometric exercise affected mainly type II muscle fibers.

  14. In vivo metabolism of pulmonary alveolar epithelial type II pneumonocytes and macrophages from Syrian hamsters

    International Nuclear Information System (INIS)

    Pfleger, R.C.; Waide, J.J.

    1976-01-01

    Young adult Syrian hamsters were injected intraperitoneally with 14 C-glycerol and 3 H-palmitate 17 hr before they were sacrificed and pulmonary alveolar epithelial type II cells and pulmonary alveolar macrophages (PAM) were isolated. Incorporation of the two labeled components into the cellular lipids showed that the 3 H-specific activity of the phospholipids from the type II cells was three times that of the PAM and the utilization of 14 C-glycerol into phosphatidyl choline (PC) was 50% greater than incorporation into the PC from PAMs. The PC from type II cells showed that 30% was disaturated and from PAMs 21% was disaturated. Another phosphatide, phosphatidyl glycerol contained about one-third of the molecules in disaturated form. These data are consistent with the view that both type II cells and PAMs can synthesize surface-active phospholipids but it is generally accepted that only the pulmonary alveolar epithelial type II cells excrete the disaturated phospholipids which comprise the surface-active components of pulmonary surfactant

  15. The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, P.; /Lisbon, LIFEP /Lisbon, IST; Aglietta, M.; /Turin Observ. /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab; Allard, D.; /APC, Paris; Allekotte, I.; /Centro Atomico Bariloche /Balseiro Inst., San Carlos de Bariloche; Allen, J.; /New York U.; Alvarez Castillo, J.; /Mexico U.; Alvarez-Muniz, J.; /Santiago de Compostela U.; Ambrosio, M.; /Naples U. /INFN, Naples; Aminaei, A.; /Nijmegen U., IMAPP; Anchordoqui, L.; /Wisconsin U., Milwaukee /Lisbon, LIFEP /Lisbon, IST

    2011-01-01

    Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.

  16. XMM FOLLOW-UP OBSERVATIONS OF THREE SWIFT BAT-SELECTED ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Trippe, M. L.; Reynolds, C. S.; Koss, M.; Mushotzky, R. F.; Winter, L. M.

    2011-01-01

    We present XMM-Newton observations of three active galactic nuclei (AGNs) taken as part of a hunt to find very heavily obscured Compton-thick AGNs. For obscuring columns greater than 10 25 cm -2 , AGNs are only visible at energies below 10 keV via reflected/scattered radiation, characterized by a flat power law. We therefore selected three objects (ESO 417-G006, IRAS 05218-1212, and MCG -01-05-047) from the Swift Burst Alert Telescope (BAT) hard X-ray survey catalog with Swift X-ray Telescope (XRT) 0.5-10 keV spectra with flat power-law indices as candidate Compton-thick sources for follow-up observations with the more sensitive instruments on XMM-Newton. The XMM spectra, however, rule out reflection-dominated models based on the weakness of the observed Fe Kα lines. Instead, the spectra are well fit by a model of a power-law continuum obscured by a Compton-thin absorber plus a soft excess. This result is consistent with previous follow-up observations of two other flat-spectrum BAT-detected AGNs. Thus, out of the six AGNs in the 22 month BAT catalog with apparently flat Swift XRT spectra, all five that have had follow-up observations are not likely Compton thick. We also present new optical spectra of two of these objects, IRAS 05218-1212 and MCG -01-05-047. Interestingly, though both the AGNs have similar X-ray spectra, their optical spectra are completely different, adding evidence against the simplest form of the geometric unified model of AGNs. IRAS 05218-1212 appears in the optical as a Seyfert 1, despite the ∼8.5 x 10 22 cm -2 line-of-sight absorbing column indicated by its X-ray spectrum. MCG -01-05-047's optical spectrum shows no sign of AGN activity; it appears as a normal galaxy.

  17. ENVIRONMENTAL EFFECTS ON THE GROWTH OF SUPERMASSIVE BLACK HOLES AND ACTIVE GALACTIC NUCLEUS FEEDBACK

    International Nuclear Information System (INIS)

    Shin, Min-Su; Ostriker, Jeremiah P.; Ciotti, Luca

    2012-01-01

    We investigate how environmental effects by gas stripping alter the growth of a supermassive black hole (SMBH) and its host galaxy evolution, by means of one-dimensional hydrodynamical simulations that include both mechanical and radiative active galactic nucleus (AGN) feedback effects. By changing the truncation radius of the gas distribution (R t ), beyond which gas stripping is assumed to be effective, we simulate possible environments for satellite and central galaxies in galaxy clusters and groups. The continuous escape of gas outside the truncation radius strongly suppresses star formation, while the growth of the SMBH is less affected by gas stripping because the SMBH accretion is primarily ruled by the density of the central region. As we allow for increasing environmental effects—the truncation radius decreasing from about 410 to 50 kpc—we find that the final SMBH mass declines from about 10 9 to 8 × 10 8 M ☉ , but the outflowing mass is roughly constant at about 2 × 10 10 M ☉ . There are larger changes in the mass of stars formed, which declines from about 2 × 10 10 to 2 × 10 9 M ☉ , and the final thermal X-ray gas, which declines from about 10 9 to 5 × 10 8 M ☉ , with increasing environmental stripping. Most dramatic is the decline in the total time that the objects would be seen as quasars, which declines from 52 Myr (for R t = 377 kpc) to 7.9 Myr (for R t = 51 kpc). The typical case might be interpreted as a red and dead galaxy having episodic cooling flows followed by AGN feedback effects resulting in temporary transitions of the overall galaxy color from red to green or to blue, with (cluster) central galaxies spending a much larger fraction of their time in the elevated state than do satellite galaxies. Our results imply that various scaling relations for elliptical galaxies, in particular, the mass ratio between the SMBH and its host galaxy, can have dispersions due to environmental effects such as gas stripping. In addition, the

  18. THE NUCLEAR INFRARED EMISSION OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R. E. [Gemini Observatory, Northern Operations Center, 670 N. A' ohoku Place, Hilo, HI 96720 (United States); Lopez-Rodriguez, E.; Packham, C. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611 (United States); Alonso-Herrero, A. [Instituto de Fisica de Cantabria, CSIC-UC, Avenida de los Castros s/n, 39005 Santander (Spain); Levenson, N. A.; Radomski, J. [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Ramos Almeida, C. [Instituto de Astrofisica de Canarias, C/Via Lactea, s/n, E-38205, La Laguna, Tenerife (Spain); Colina, L. [Departamento de Astrofisica, Centro de Astrobiologia (CSIC/INTA), Instituto Nacional de Tecnica Aeroespacial, Crta de Torrejon a Ajalvir, km 4, 28850 Torrejon de Ardoz, Madrid (Spain); Elitzur, M. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Aretxaga, I. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla (Mexico); Roche, P. F. [Astrophysics, Department of Physics, University of Oxford, DWB, Keble Road, Oxford OX1 3RH (United Kingdom); Oi, N. [Department of Astronomy, School of Science, Graduate University for Advanced Studies (SOKENDAI), Mitaka, Tokyo 181-8588 (Japan)

    2012-07-15

    We present high-resolution mid-infrared (MIR) imaging, nuclear spectral energy distributions (SEDs), and archival Spitzer spectra for 22 low-luminosity active galactic nuclei (LLAGNs; L{sub bol} {approx}< 10{sup 42} erg s{sup -1}). Infrared (IR) observations may advance our understanding of the accretion flows in LLAGNs, the fate of the obscuring torus at low accretion rates, and, perhaps, the star formation histories of these objects. However, while comprehensively studied in higher-luminosity Seyferts and quasars, the nuclear IR properties of LLAGNs have not yet been well determined. We separate the present LLAGN sample into three categories depending on their Eddington ratio and radio emission, finding different IR characteristics for each class. (1) At the low-luminosity, low-Eddington-ratio (log L{sub bol}/L{sub Edd} < -4.6) end of the sample, we identify 'host-dominated' galaxies with strong polycyclic aromatic hydrocarbon bands that may indicate active (circum-)nuclear star formation. (2) Some very radio-loud objects are also present at these low Eddington ratios. The IR emission in these nuclei is dominated by synchrotron radiation, and some are likely to be unobscured type 2 AGNs that genuinely lack a broad-line region. (3) At higher Eddington ratios, strong, compact nuclear sources are visible in the MIR images. The nuclear SEDs of these galaxies are diverse; some resemble typical Seyfert nuclei, while others lack a well-defined MIR 'dust bump'. Strong silicate emission is present in many of these objects. We speculate that this, together with high ratios of silicate strength to hydrogen column density, could suggest optically thin dust and low dust-to-gas ratios, in accordance with model predictions that LLAGNs do not host a Seyfert-like obscuring torus. We anticipate that detailed modeling of the new data and SEDs in terms of accretion disk, jet, radiatively inefficient accretion flow, and torus components will provide further

  19. CD1d-Restricted Type II NKT Cells Reactive With Endogenous Hydrophobic Peptides.

    Science.gov (United States)

    Nishioka, Yusuke; Masuda, Sakiko; Tomaru, Utano; Ishizu, Akihiro

    2018-01-01

    NKT cells belong to a distinct subset of T cells that recognize hydrophobic antigens presented by major histocompatibility complex class I-like molecules, such as CD1d. Because NKT cells stimulated by antigens can activate or suppress other immunocompetent cells through an immediate production of a large amount of cytokines, they are regarded as immunological modulators. CD1d-restricted NKT cells are classified into two subsets, namely, type I and type II. CD1d-restricted type I NKT cells express invariant T cell receptors (TCRs) and react with lipid antigens, including the marine sponge-derived glycolipid α-galactosylceramide. On the contrary, CD1d-restricted type II NKT cells recognize a wide variety of antigens, including glycolipids, phospholipids, and hydrophobic peptides, by their diverse TCRs. In this review, we focus particularly on CD1d-restricted type II NKT cells that recognize endogenous hydrophobic peptides presented by CD1d. Previous studies have demonstrated that CD1d-restricted type I NKT cells usually act as pro-inflammatory cells but sometimes behave as anti-inflammatory cells. It has been also demonstrated that CD1d-restricted type II NKT cells play opposite roles to CD1d-restricted type I NKT cells; thus, they function as anti-inflammatory or pro-inflammatory cells depending on the situation. In line with this, CD1d-restricted type II NKT cells that recognize type II collagen peptide have been demonstrated to act as anti-inflammatory cells in diverse inflammation-induction models in mice, whereas pro-inflammatory CD1d-restricted type II NKT cells reactive with sterol carrier protein 2 peptide have been demonstrated to be involved in the development of small vessel vasculitis in rats.

  20. Induction of expression of two phenotypic markers of pulmonary type II cells in a cultured cell line

    International Nuclear Information System (INIS)

    Henderson, R.F.; Waide, J.J.; Scott, G.G.

    1994-01-01

    The functions of pulmonary type II cells, such as synthesis of pulmonary surfactant and metabolism of inhaled xenobiotics, can be studied in primary isolates of lung cells. However, isolated type II cells, when cultured, quickly lose the phenotypic expressions characteristics of type II cells, including surfactant lipid and protein synthesis and alkaline phosphatase (AP) activity. A cultured cell line that maintained expression of type II cell markers of differentiation would be advantageous for the study of such functions as surfactant synthesis and secretion. Such a cell line would allow generation of a large number of homogeneous cells for study. The purpose of the current study was to induce markers of differentiated type II cells in a cultured cell line to facilitate studies of factors that control surfactant synthesis and secretion

  1. Glycogen storage disease type II (Pompe disease in children

    Directory of Open Access Journals (Sweden)

    A. N. Semyachkina

    2014-01-01

    Full Text Available The paper gives the data available in the literature, which reflect the manifestations, diagnosis, and current treatments of the rare (orphan inherited disease glycogen storage disease type II or Pomp disease in children, as well as its classification. The infant form is shown to be most severe, resulting in death from cardiovascular or pulmonary failure generally within the first year of a child’s life. Emphasis is laid on major difficulties in the differential and true diagnosis of this severe disease. Much attention is given to the new pathogenetic treatment — genetically engineered enzyme replacement drug Myozyme®. The authors describe their clinical case of a child with the juvenile form of glycogen storage disease type II (late-onset Pompe disease. Particular emphasis is laid on the clinical symptoms of the disease and its diagnostic methods, among which the morphological analysis of a muscle biopsy specimen by light and electron microscopies, and enzyme and DNA diagnoses are of most importance. The proband was found to have significant lysosomal glycogen accumulation in the muscle biopsy specimen, reduced lymphocyte acid α-1,4-glucosidase activity to 4,2 nM/mg/h (normal value, 13,0—53,6 nM/mg/h, described in the HGMD missense mutation database from 1000 G>A p.Gly334er of the GAA in homozygous state, which verified the diagnosis of Pompe disease. 

  2. Active galactic nucleus and quasar science with aperture masking interferometry on the James Webb Space Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ford, K. E. Saavik; McKernan, Barry [Department of Science, Borough of Manhattan Community College, City University of New York, New York, NY 10007 (United States); Sivaramakrishnan, Anand; Martel, André R.; Koekemoer, Anton [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lafrenière, David [Département de Physique, Université de Montréal, C.P. 6128 Succ. Centre-ville, QC H3C 3J7 (Canada); Parmentier, Sébastien [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

    2014-03-10

    Due to feedback from accretion onto supermassive black holes (SMBHs), active galactic nuclei (AGNs) are believed to play a key role in ΛCDM cosmology and galaxy formation. However, AGNs extreme luminosities and the small angular size of their accretion flows create a challenging imaging problem. We show that the James Webb Space Telescope's Near Infrared Imager and Slitless Spectrograph (JWST-NIRISS) Aperture Masking Interferometry (AMI) mode will enable true imaging (i.e., without any requirement of prior assumptions on source geometry) at ∼65 mas angular resolution at the centers of AGNs. This is advantageous for studying complex extended accretion flows around SMBHs and in other areas of angular-resolution-limited astrophysics. By simulating data sequences incorporating expected sources of noise, we demonstrate that JWST-NIRISS AMI mode can map extended structure at a pixel-to-pixel contrast of ∼10{sup –2} around an L = 7.5 point source, using short exposure times (minutes). Such images will test models of AGN feedback, fueling, and structure (complementary with ALMA observations), and are not currently supported by any ground-based IR interferometer or telescope. Binary point source contrast with NIRISS is ∼10{sup –4} (for observing binary nuclei in merging galaxies), significantly better than current ground-based optical or IR interferometry. JWST-NIRISS's seven-hole non-redundant mask has a throughput of 15%, and utilizes NIRISS's F277W (2.77 μm), F380M (3.8 μm), F430M (4.3 μm), and F480M (4.8 μm) filters. NIRISS's square pixels are 65 mas per side, with a field of view ∼2' × 2'. We also extrapolate our results to AGN science enabled by non-redundant masking on future 2.4 m and 16 m space telescopes working at long-UV to near-IR wavelengths.

  3. Fe-K LINE PROBING OF MATERIAL AROUND THE ACTIVE GALACTIC NUCLEUS CENTRAL ENGINE WITH SUZAKU

    International Nuclear Information System (INIS)

    Fukazawa, Yasushi; Hiragi, Kazuyoshi; Mizuno, Motohiro; Nishino, Sho; Hayashi, Katsuhiro; Yamasaki, Tomonori; Shirai, Hirohisa; Takahashi, Hiromitsu; Ohno, Masanori

    2011-01-01

    We systematically analyzed the high-quality Suzaku data of 88 Seyfert galaxies, about 31% of which are Compton-thick active galactic nuclei (AGNs). We obtained a clear relation between the absorption column density and the equivalent width (EW) of the 6.4 keV line above 10 23 cm -2 , suggesting a wide-ranging column density of 10 23 -10 24.5 cm -2 with a similar solid and an Fe abundance of 0.7-1.3 solar for Seyfert 2 galaxies. The EWs of the 6.4 keV line for Seyfert 1 galaxies are typically 40-120 eV, suggesting the existence of Compton-thick matter like the torus with a column density of >10 23 cm -2 and a solid angle of (0.15-0.4) x 4π, and no difference of neutral matter is visible between Seyfert 1 and 2 galaxies. An absorber with a lower column density of 10 21 -10 23 cm -2 for Compton-thin Seyfert 2 galaxies is suggested to be not a torus but an interstellar medium. These constraints can be understood by the fact that the 6.4 keV line intensity ratio against the 10-50 keV flux is almost identical within a range of 2-3 in many Seyfert galaxies. Interestingly, objects exist with a low EW, 10-30 eV, of the 6.4 keV line, suggesting that those torus subtends only a small solid angle of H >10 23 cm -2 indicates that the column density of the ionized material also increases together with that of the cold material. It is found that these features seem to change for brighter objects with more than several 10 44 erg s -1 such that the Fe-K line features become weak. This extends the previously known X-ray Baldwin effect on the neutral Fe-Kα line to ionized emission or absorption lines. The luminosity dependence of these properties, regardless of the scatter of black hole mass by two orders of magnitudes, indicates that the ionized material is associated with the structure of the parent galaxy rather than the outflow from the nucleus.

  4. Stellar Photometric Structures of the Host Galaxies of Nearby Type 1 Active Galactic Nuclei

    Science.gov (United States)

    Kim, Minjin; Ho, Luis C.; Peng, Chien Y.; Barth, Aaron J.; Im, Myungshin

    2017-10-01

    We present detailed image analysis of rest-frame optical images of 235 low-redshift (z ≲ 0.35) Type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope. The high-resolution images enable us to perform rigorous two-dimensional image modeling to decouple the luminous central point source from the host galaxy, which, when warranted, is further decomposed into its principal structural components (bulge, bar, and disk). In many cases, care must be taken to account for structural complexities such as spiral arms, tidal features, and overlapping or interacting companion galaxies. We employ Fourier modes to characterize the degree of asymmetry of the light distribution of the stars as a quantitative measure of morphological distortion due to interactions or mergers. We examine the dependence of the physical parameters of the host galaxies on the properties of the AGNs, namely, radio-loudness and the width of the broad emission lines. In accordance with previous studies, narrow-line (Hβ FWHM ≤ 2000 km s-1) Type 1 AGNs, in contrast to their broad-line (Hβ FWHM > 2000 km s-1) counterparts, are preferentially hosted in later-type, lower-luminosity galaxies, which have a higher incidence of pseudo-bulges, are more frequently barred, and are less morphologically disturbed. This suggests that narrow-line Type 1 AGNs experienced a more quiescent evolutionary history driven primarily by internal secular evolution instead of external dynamical perturbations. The fraction of AGN hosts showing merger signatures is larger for more luminous sources. Radio-loud AGNs generally preferentially live in earlier-type (bulge-dominated), more massive hosts, although a minority of them appear to contain a significant disk component. We do not find convincing evidence for enhanced merger signatures in the radio-loud population. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute

  5. THE NATURE OF ACTIVE GALACTIC NUCLEI WITH VELOCITY OFFSET EMISSION LINES

    Energy Technology Data Exchange (ETDEWEB)

    Müller-Sánchez, F.; Comerford, J. [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Harrison, F. A. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2016-10-10

    We obtained Keck/OSIRIS near-IR adaptive optics-assisted integral-field spectroscopy to probe the morphology and kinematics of the ionized gas in four velocity-offset active galactic nuclei (AGNs) from the Sloan Digital Sky Survey. These objects possess optical emission lines that are offset in velocity from systemic as measured from stellar absorption features. At a resolution of ∼0.″18, OSIRIS allows us to distinguish which velocity offset emission lines are produced by the motion of an AGN in a dual supermassive black hole system, and which are produced by outflows or other kinematic structures. In three galaxies, J1018+2941, J1055+1520, and J1346+5228, the spectral offset of the emission lines is caused by AGN-driven outflows. In the remaining galaxy, J1117+6140, a counterrotating nuclear disk is observed that contains the peak of Pa α emission 0.″2 from the center of the galaxy. The most plausible explanation for the origin of this spatially and kinematically offset peak is that it is a region of enhanced Pa α emission located at the intersection zone between the nuclear disk and the bar of the galaxy. In all four objects, the peak of ionized gas emission is not spatially coincident with the center of the galaxy as traced by the peak of the near-IR continuum emission. The peaks of ionized gas emission are spatially offset from the galaxy centers by 0.″1–0.″4 (0.1–0.7 kpc). We find that the velocity offset originates at the location of this peak of emission, and the value of the offset can be directly measured in the velocity maps. The emission-line ratios of these four velocity-offset AGNs can be reproduced only with a mixture of shocks and AGN photoionization. Shocks provide a natural explanation for the origin of the spatially and spectrally offset peaks of ionized gas emission in these galaxies.

  6. MAGNETOHYDRODYNAMIC ACCRETION DISK WINDS AS X-RAY ABSORBERS IN ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Fukumura, Keigo; Kazanas, Demosthenes; Behar, Ehud; Contopoulos, Ioannis

    2010-01-01

    We present the two-dimensional ionization structure of self-similar magnetohydrodynamic winds off accretion disks around and irradiated by a central X-ray point source. On the basis of earlier observational clues and theoretical arguments, we focus our attention on a subset of these winds, namely those with radial density dependence n(r) ∝ 1/r (r is the spherical radial coordinate). We employ the photoionization code XSTAR to compute the ionic abundances of a large number of ions of different elements and then compile their line-of-sight (LOS) absorption columns. We focus our attention on the distribution of the column density of the various ions as a function of the ionization parameter ξ (or equivalently r) and the angle θ. Particular attention is paid to the absorption measure distribution (AMD), namely their hydrogen-equivalent column per logarithmic ξ interval, dN H /dlog ξ, which provides a measure of the winds' radial density profiles. For the chosen density profile n(r) ∝ 1/r, the AMD is found to be independent of ξ, in good agreement with its behavior inferred from the X-ray spectra of several active galactic nuclei (AGNs). For the specific wind structure and X-ray spectrum, we also compute detailed absorption line profiles for a number of ions to obtain their LOS velocities, v ∼ 100-300 km s -1 (at log ξ ∼ 2-3) for Fe XVII and v ∼ 1000-4000 km s -1 (at log ξ ∼ 4-5) for Fe XXV, in good agreement with the observation. Our models describe the X-ray absorption properties of these winds with only two parameters, namely the mass-accretion rate m-dot and the LOS angle θ. The probability of obscuration of the X-ray ionizing source in these winds decreases with increasing m-dot and increases steeply with the LOS inclination angle θ. As such, we concur with previous authors that these wind configurations, viewed globally, incorporate all the requisite properties of the parsec scale 'torii' invoked in AGN unification schemes. We indicate that a

  7. CO Spectral Line Energy Distributions of Infrared-Luminous Galaxies and Active Galactic Nuclei

    Science.gov (United States)

    Papadopoulos, Padeli P.; van der Werf, Paul; Isaak, Kate; Xilouris, Emmanuel M.

    2010-06-01

    We report on new sensitive CO J = 6-5 line observations of several luminous infrared galaxies (LIRGs; L IR(8-1000 μm) >~ 1011 L sun), 36% (8/22) of them ultraluminous infrared galaxies (ULIRGs) (L IR>1012 L sun), and two powerful local active galactic nuclei (AGNs)—the optically luminous QSO PG 1119+120 and the powerful radio galaxy 3C 293—using the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. We combine these observations with existing low-J CO data and dust emission spectral energy distributions in the far-infrared-submillimeter from the literature to constrain the properties of the star-forming interstellar medium (ISM) in these systems. We then build the first local CO spectral line energy distributions (SLEDs) for the global molecular gas reservoirs that reach up to high J-levels. These CO SLEDs are neither biased by strong lensing (which affects many of those constructed for high-redshift galaxies), nor suffer from undersampling of CO-bright regions (as most current high-J CO observations of nearby extended systems do). We find: (1) a significant influence of dust optical depths on the high-J CO lines, suppressing the J = 6-5 line emission in some of the most IR-luminous LIRGs, (2) low global CO line excitation possible even in vigorously star-forming systems, (3) the first case of a shock-powered high-excitation CO SLED in the radio galaxy 3C 293 where a powerful jet-ISM interaction occurs, and (4) unusually highly excitated gas in the optically powerful QSO PG 1119+120. In Arp 220 and possibly other (U)LIRGs very faint CO J = 6-5 lines can be attributed to significant dust optical depths at short submillimeter wavelengths immersing those lines in a strong dust continuum, and also causing the C+ line luminosity deficit often observed in such extreme starbursts. Re-analysis of the CO line ratios available for submillimeter galaxies suggests that similar dust opacities also may be present in these high-redshift starbursts, with genuinely low

  8. CO SPECTRAL LINE ENERGY DISTRIBUTIONS OF INFRARED-LUMINOUS GALAXIES AND ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Papadopoulos, Padeli P.; Van der Werf, Paul; Isaak, Kate; Xilouris, Emmanuel M.

    2010-01-01

    We report on new sensitive CO J = 6-5 line observations of several luminous infrared galaxies (LIRGs; L IR (8-1000 μm) ∼> 10 11 L sun ), 36% (8/22) of them ultraluminous infrared galaxies (ULIRGs) (L IR >10 12 L sun ), and two powerful local active galactic nuclei (AGNs)-the optically luminous QSO PG 1119+120 and the powerful radio galaxy 3C 293-using the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. We combine these observations with existing low-J CO data and dust emission spectral energy distributions in the far-infrared-submillimeter from the literature to constrain the properties of the star-forming interstellar medium (ISM) in these systems. We then build the first local CO spectral line energy distributions (SLEDs) for the global molecular gas reservoirs that reach up to high J-levels. These CO SLEDs are neither biased by strong lensing (which affects many of those constructed for high-redshift galaxies), nor suffer from undersampling of CO-bright regions (as most current high-J CO observations of nearby extended systems do). We find: (1) a significant influence of dust optical depths on the high-J CO lines, suppressing the J = 6-5 line emission in some of the most IR-luminous LIRGs, (2) low global CO line excitation possible even in vigorously star-forming systems, (3) the first case of a shock-powered high-excitation CO SLED in the radio galaxy 3C 293 where a powerful jet-ISM interaction occurs, and (4) unusually highly excitated gas in the optically powerful QSO PG 1119+120. In Arp 220 and possibly other (U)LIRGs very faint CO J = 6-5 lines can be attributed to significant dust optical depths at short submillimeter wavelengths immersing those lines in a strong dust continuum, and also causing the C + line luminosity deficit often observed in such extreme starbursts. Re-analysis of the CO line ratios available for submillimeter galaxies suggests that similar dust opacities also may be present in these high-redshift starbursts, with genuinely low

  9. Determining the Covering Factor of Compton-Thick Active Galactic Nuclei with NuSTAR

    Science.gov (United States)

    Brightman, M.; Balokovic, M.; Stern, D.; Arevalo, P.; Ballantyne, D. R.; Bauer, F. E.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Zhang, W. W.

    2015-01-01

    The covering factor of Compton-thick (CT) obscuring material associated with the torus in active galactic nuclei (AGNs) is at present best understood through the fraction of sources exhibiting CT absorption along the line of sight (N(sub H) greater than 1.5 x 10(exp 24) cm(exp -2)) in the X-ray band, which reveals the average covering factor. Determining this CT fraction is difficult, however, due to the extreme obscuration. With its spectral coverage at hard X-rays (greater than 10 keV), Nuclear Spectroscopic Telescope Array (NuSTAR) is sensitive to the AGNs covering factor since Compton scattering of X-rays off optically thick material dominates at these energies. We present a spectral analysis of 10 AGNs observed with NuSTAR where the obscuring medium is optically thick to Compton scattering, so-called CT AGNs. We use the torus models of Brightman and Nandra that predict the X-ray spectrum from reprocessing in a torus and include the torus opening angle as a free parameter and aim to determine the covering factor of the CT gas in these sources individually. Across the sample we find mild to heavy CT columns, with N(sub H) measured from 10(exp 24) to 10(exp 26) cm(exp -2), and a wide range of covering factors, where individual measurements range from 0.2 to 0.9. We find that the covering factor, f(sub c), is a strongly decreasing function of the intrinsic 2-10 keV luminosity, L(sub X), where f(sub c) = (-0.41 +/- 0.13)log(sub 10)(L(sub X)/erg s(exp -1))+18.31 +/- 5.33, across more than two orders of magnitude in L(sub X) (10(exp 41.5) - 10(exp 44) erg s(exp -1)). The covering factors measured here agree well with the obscured fraction as a function of LX as determined by studies of local AGNs with L(sub X) greater than 10(exp 42.5) erg s(exp -1).

  10. Active galactic nucleus X-ray variability in the XMM-COSMOS survey

    Energy Technology Data Exchange (ETDEWEB)

    Lanzuisi, G.; Ponti, G.; Salvato, M.; Brusa, M.; Nandra, P. K.; Merloni, A.; Rosario, D. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Hasinger, G.; Sanders, D. [Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822-1839 (United States); Cappelluti, N.; Comastri, A.; Gilli, R. [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Bongiorno, A. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Roma Via Frascati 33, I-00040, Monte Porzio Catone (Italy); Lusso, E.; Steinhardt, C. [Max Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Silverman, J.; Schramm, M. [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) 5-1-5 Kashiwanoha Kashiwa, Chiba 277-8583 (Japan); Trump, J. [University of California Observatories/Lick Observatory and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Vignali, C. [Dipartimento di Fisica e Astronomia, Universitá di Bologna, viale Berti Pichat 6/2, I-40127 Bologna (Italy); Kartaltepe, J., E-mail: lanzuisi@noa.gr [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); and others

    2014-02-01

    We used the observations carried out by XMM in the COSMOS field over 3.5 yr to study the long term variability of a large sample of active galactic nuclei (AGNs) (638 sources) in a wide range of redshifts (0.1 < z < 3.5) and X-ray luminosities (10{sup 41} < L {sub 0.5-10} <10{sup 45.5}). Both a simple statistical method to assess the significance of variability and the Normalized Excess Variance (σ{sub rms}{sup 2}) parameter were used to obtain a quantitative measurement of the variability. Variability is found to be prevalent in most AGNs, whenever we have good statistics to measure it, and no significant differences between type 1 and type 2 AGNs were found. A flat (slope –0.23 ± 0.03) anti-correlation between σ{sub rms}{sup 2} and X-ray luminosity is found when all significantly variable sources are considered together. When divided into three redshift bins, the anti-correlation becomes stronger and evolving with z, with higher redshift AGNs being more variable. We prove, however, that this effect is due to the pre-selection of variable sources: when considering all of the sources with an available σ{sub rms}{sup 2} measurement, the evolution in redshift disappears. For the first time, we were also able to study long term X-ray variability as a function of M {sub BH} and Eddington ratio for a large sample of AGNs spanning a wide range of redshifts. An anti-correlation between σ{sub rms}{sup 2} and M {sub BH} is found, with the same slope of anti-correlation between σ{sub rms}{sup 2} and X-ray luminosity, suggesting that the latter may be a by-product of the former. No clear correlation is found between σ{sub rms}{sup 2} and the Eddington ratio in our sample. Finally, no correlation is found between the X-ray σ{sub rms}{sup 2} and optical variability.

  11. The Nature of Double-peaked [O III] Active Galactic Nuclei

    Science.gov (United States)

    Fu, Hai; Yan, Lin; Myers, Adam D.; Stockton, Alan; Djorgovski, S. G.; Aldering, G.; Rich, Jeffrey A.

    2012-01-01

    Active galactic nuclei (AGNs) with double-peaked [O III] lines are suspected to be sub-kpc or kpc-scale binary AGNs. However, pure gas kinematics can produce the same double-peaked line profile in spatially integrated spectra. Here we combine integral-field spectroscopy and high-resolution imaging of 42 double-peaked [O III] AGNs from the Sloan Digital Sky Survey to investigate the constituents of the population. We find two binary AGNs where the line splitting is driven by the orbital motion of the merging nuclei. Such objects account for only ~2% of the double-peaked AGNs. Almost all (~98%) of the double-peaked AGNs were selected because of gas kinematics; and half of those show spatially resolved narrow-line regions that extend 4-20 kpc from the nuclei. Serendipitously, we find two spectrally unresolved binary AGNs where gas kinematics produced the double-peaked [O III] lines. The relatively frequent serendipitous discoveries indicate that only ~1% of binary AGNs would appear double-peaked in Sloan spectra and 2.2+2.5 -0.8% of all Sloan AGNs are binary AGNs. Therefore, the double-peaked sample does not offer much advantage over any other AGN samples in finding binary AGNs. The binary AGN fraction implies an elevated AGN duty cycle (8+8 -3%), suggesting galaxy interactions enhance nuclear accretion. We illustrate that integral-field spectroscopy is crucial for identifying binary AGNs: several objects previously classified as "binary AGNs" with long-slit spectra are most likely single AGNs with extended narrow-line regions (ENLRs). The formation of ENLRs driven by radiation pressure is also discussed. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  12. INFRARED CLASSIFICATION AND LUMINOSITIES FOR DUSTY ACTIVE GALACTIC NUCLEI AND THE MOST LUMINOUS QUASARS

    International Nuclear Information System (INIS)

    Weedman, Daniel; Sargsyan, Lusine; Houck, James; Barry, Donald; Lebouteiller, Vianney

    2012-01-01

    Mid-infrared spectroscopic measurements from the Infrared Spectrometer (IRS) on Spitzer are given for 125 hard X-ray active galactic nuclei (AGNs; 14-195 keV) from the Swift Burst Alert Telescope (BAT) sample and for 32 AGNs with black hole masses (BHMs) from reverberation mapping. The 9.7 μm silicate feature in emission or absorption defines an infrared AGN classification describing whether AGNs are observed through dust clouds, indicating that 55% of the BAT AGNs are observed through dust. The mid-infrared dust continuum luminosity is shown to be an excellent indicator of intrinsic AGN luminosity, scaling closely with the hard X-ray luminosity, log νL ν (7.8 μm)/L(X) = –0.31 ± 0.35, and independent of classification determined from silicate emission or absorption. Dust luminosity scales closely with BHM, log νL ν (7.8 μm) = (37.2 ± 0.5) + 0.87 log BHM for luminosity in erg s –1 and BHM in M ☉ . The 100 most luminous type 1 quasars as measured in νL ν (7.8 μm) are found by comparing Sloan Digital Sky Survey (SDSS) optically discovered quasars with photometry at 22 μm from the Wide-Field Infrared Survey Explorer (WISE), scaled to rest frame 7.8 μm using an empirical template determined from IRS spectra. The most luminous SDSS/WISE quasars have the same maximum infrared luminosities for all 1.5 IR = 10 14.4 L ☉ . Comparing with dust-obscured galaxies from Spitzer and WISE surveys, we find no evidence of hyperluminous obscured quasars whose maximum infrared luminosities exceed the maximum infrared luminosities of optically discovered quasars. Bolometric luminosities L bol estimated from rest-frame optical or ultraviolet luminosities are compared to L IR . For the local AGN, the median log L IR /L bol = –0.35, consistent with a covering factor of 45% for the absorbing dust clouds. For the SDSS/WISE quasars, the median log L IR /L bol = 0.1, with extremes indicating that ultraviolet-derived L bol can be seriously underestimated even for type 1

  13. MOJAVE: Monitoring of jets in active galactic nuclei with VLBA experiments. XI. Spectral distributions

    Energy Technology Data Exchange (ETDEWEB)

    Hovatta, Talvikki [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Aller, Margo F.; Aller, Hugh D. [Department of Astronomy, University of Michigan, 830 Dennison Building, Ann Arbor, MI 48109-1042 (United States); Clausen-Brown, Eric; Kovalev, Yuri Y.; Pushkarev, Alexander B.; Savolainen, Tuomas [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Homan, Daniel C. [Department of Physics and Astronomy, Denison University, Granville, OH 43023 (United States); Lister, Matthew L., E-mail: thovatta@caltech.edu [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

    2014-06-01

    We have obtained milliarcsecond-scale spectral index distributions for a sample of 190 extragalactic radio jets through the Monitoring of Jets in Active Galactic Nuclei with the VLBA Experiments (MOJAVE) project. The sources were observed in 2006 at 8.1, 8.4, 12.1, and 15.4 GHz, and we have determined spectral index maps between 8.1 and 15.4 GHz to study the four-frequency spectrum in individual jet features. We have performed detailed simulations to study the effects of image alignment and (u, v)-plane coverage on the spectral index maps to verify our results. We use the spectral index maps to study the spectral index evolution along the jet and determine the spectral distributions in different locations of the jets. The core spectral indices are on average flat with a mean value of +0.22 ± 0.03 for the sample, while the jet spectrum is in general steep with a mean index of –1.04 ± 0.03. A simple power-law fit is often inadequate for the core regions, as expected if the cores are partially self-absorbed. The overall jet spectrum steepens at a rate of about –0.001 to –0.004 per deprojected parsec when moving further out from the core with flat spectrum radio quasars having significantly steeper spectra (mean –1.09 ± 0.04) than the BL Lac objects (mean –0.80 ± 0.05). However, the spectrum in both types of objects flattens on average by ∼0.2 at the locations of the jet components indicating particle acceleration or density enhancements along the jet. The mean spectral index at the component locations of –0.81 ± 0.02 corresponds to a power-law index of ∼2.6 for the electron energy distribution. We find a significant trend that jet components with linear polarization parallel to the jet (magnetic field perpendicular to the jet) have flatter spectra, as expected for transverse shocks. Compared to quasars, BL Lacs have more jet components with perpendicular magnetic field alignment, which may explain their generally flatter spectra. The overall

  14. TANAMI: Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry. II. Additional sources

    Science.gov (United States)

    Müller, C.; Kadler, M.; Ojha, R.; Schulz, R.; Trüstedt, J.; Edwards, P. G.; Ros, E.; Carpenter, B.; Angioni, R.; Blanchard, J.; Böck, M.; Burd, P. R.; Dörr, M.; Dutka, M. S.; Eberl, T.; Gulyaev, S.; Hase, H.; Horiuchi, S.; Katz, U.; Krauß, F.; Lovell, J. E. J.; Natusch, T.; Nesci, R.; Phillips, C.; Plötz, C.; Pursimo, T.; Quick, J. F. H.; Stevens, J.; Thompson, D. J.; Tingay, S. J.; Tzioumis, A. K.; Weston, S.; Wilms, J.; Zensus, J. A.

    2018-02-01

    Context. TANAMI is a multiwavelength program monitoring active galactic nuclei (AGN) south of - 30° declination including high-resolution very long baseline interferometry (VLBI) imaging, radio, optical/UV, X-ray, and γ-ray studies. We have previously published first-epoch8.4 GHz VLBI images of the parsec-scale structure of the initial sample. In this paper, we present images of 39 additional sources. The full sample comprises most of the radio- and γ-ray brightest AGN in the southern quarter of the sky, overlapping with the region from which high-energy (> 100 TeV) neutrino events have been found. Aims: We characterize the parsec-scale radio properties of the jets and compare them with the quasi-simultaneous Fermi/LAT γ-ray data. Furthermore, we study the jet properties of sources which are in positional coincidence with high-energy neutrino events compared to the full sample. We test the positional agreement of high-energy neutrino events with various AGN samples. Methods: TANAMI VLBI observations at 8.4 GHz are made with southern hemisphere radio telescopes located in Australia, Antarctica, Chile, New Zealand, and South Africa. Results: Our observations yield the first images of many jets below - 30° declination at milliarcsecond resolution. We find that γ-ray loud TANAMI sources tend to be more compact on parsec-scales and have higher core brightness temperatures than γ-ray faint jets, indicating higher Doppler factors. No significant structural difference is found between sources in positional coincidence with high-energy neutrino events and other TANAMI jets. The 22 γ-ray brightest AGN in the TANAMI sky show only a weak positional agreement with high-energy neutrinos demonstrating that the > 100 TeV IceCube signal is not simply dominated by a small number of the γ-ray brightest blazars. Instead, a larger number of sources have to contribute to the signal with each individual source having only a small Poisson probability for producing an event in

  15. ACTIVE GALACTIC NUCLEUS FEEDBACK AT z ∼ 2 AND THE MUTUAL EVOLUTION OF ACTIVE AND INACTIVE GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Cimatti, A.; Brusa, M.; Talia, M. [Dipartimento di Fisica e Astronomia, Università di Bologna, Viale Berti Pichat 6/2, I-30127 Bologna (Italy); Mignoli, M. [INAF, Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Rodighiero, G. [Dipartimento di Fisica e Astronomia, Università di Padova, Vicolo dell' Osservatorio 3, I-35122 Padova (Italy); Kurk, J. [Max-Planck-Institut für Extraterrestrial Physik, Giessenbachstrasse, D-85748 Garching bei München (Germany); Cassata, P. [Aix Marseille Universite, CNRS, Laboratoire d' Astrophysique de Marseille, UMR 7326, F-13388 Marseille (France); Halliday, C. [23 rue d' Yerres, F-91230 Montgeron (France); Renzini, A. [INAF, Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Daddi, E., E-mail: a.cimatti@unibo.it [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d' Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette Cedex (France)

    2013-12-10

    The relationship between galaxies of intermediate stellar mass and moderate luminosity active galactic nuclei (AGNs) at 1 < z < 3 is investigated with a Galaxy Mass Assembly ultra-deep Spectroscopic Survey (GMASS) sample complemented with public data in the GOODS-South field. Using X-ray data, hidden AGNs are identified in unsuspected star-forming galaxies with no apparent signs of non-stellar activity. In the color-mass plane, two parallel trends emerge during the ∼2 Gyr between the average redshifts z ∼ 2.2 and z ∼ 1.3: while the red sequence becomes significantly more populated by ellipticals, the majority of AGNs with L(2-10 keV) > 10{sup 42.3} erg s{sup –1} disappear from the blue cloud/green valley where they were hosted predominantly by star-forming systems with disk and irregular morphologies. These results are even clearer when the rest-frame colors are corrected for dust reddening. At z ∼ 2.2, the ultraviolet spectra of active galaxies (including two Type 1 AGNs) show possible gas outflows with velocities up to about –500 km s{sup –1}, which are observed neither in inactive systems at the same redshift, nor at lower redshifts. Such outflows indicate the presence of gas that can move faster than the escape velocities of active galaxies. These results suggest that feedback from moderately luminous AGNs (log L{sub X} < 44.5 erg s{sup –1}) played a key role at z ≳ 2 by contributing to outflows capable of ejecting part of the interstellar medium and leading to a rapid decrease in star formation in host galaxies with stellar masses 10 < log(M/M{sub ⊙})< 11.

  16. Observations of active galactic nuclei from radio to gamma-rays

    International Nuclear Information System (INIS)

    Boeck, Moritz

    2013-01-01

    In this work, Active Galactic Nuclei (AGN) - the brightest persistent objects in the universe - are discussed. According to current knowledge they consist out of several components. The central object of such systems is a supermassive black hole located in the center of a galaxy. Estimated masses of such black holes range from millions to billions of solar masses. The enormous gravitational field of the black hole affects material in its surrounding. Matter, such as gas, dust particles or stellar wind virtually provides the fuel for the AGN. The accretion process is highly efficient and partly explains the extreme luminosities of Active Galactic Nuclei. The thermal emission of the accretion disk is, however, insufficient for explaining the total emission of AGN. Observations show that some of these objects are visible throughout the complete electromagnetic spectrum. The emission in the radio regime as well as, most likely, high-energy emission seem to originate from jets. Unlike material accreted by the black hole, jets are collimated outflows with velocities near the speed of light. AGN are not completely understood. There are numerous open questions remaining, such as the exact accretion geometry, the formation and composition of the relativistic jets, the interaction between different components of these systems, as well as the place of origin and the underlying physical processes of the emission in different energy ranges. In order to address these questions a multiwavelength analysis of AGN has been performed in this work. The different energy regimes and observational techniques allow for insights into different processes and properties of such objects. A study of the connection between the accretion disk and properties of the jet has been done based on the object NGC 1052 using radio and X-ray observations. This object is a galaxy with an active nucleus. In the radio regime a double-sided jet with a projected length of several kpc is visible. In addition

  17. Galactic sprinklers

    International Nuclear Information System (INIS)

    Vandeusen, W.

    1984-01-01

    It is believed by many astronomers that gravitation is responsible for holding a strong whirlpool of hot, dense material together at the center of the Milky Way galaxy. However, the galactic-sprinkler model suggests that the whirlpool is not being held together, and that the stars, gas and dust within the spirals are being thrown outward. It is also suggested that much of the ejected material eventually returns to the galactic center, as do stars within our stellar neighborhood. The material is believed to be subjected to extreme changes in the gravitational time rate which may cause it to follow an inbound spiral that is basically similar to the outbound spiral. Radio studies also indicate that the galactic arms on either side of the galactic center move at different velocities and in different directions with respect to our location and that the whole group of stars in the vicinity of the solar system may be moving outward from the galactic center at a velocity of about 40 kps. Through the use of velocity data in kps, and distance data in light years, the radial component of the sun's trajectory can be estimated with respect to time by a parabola. The spiral trajectory of the sun can be calculated and plotted on polar coordinates by combining both the radial component and tangential component (230 kps)

  18. GOODS-HERSCHEL: SEPARATING HIGH-REDSHIFT ACTIVE GALACTIC NUCLEI AND STAR-FORMING GALAXIES USING INFRARED COLOR DIAGNOSTICS

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, Allison; Pope, Alexandra [Department of Astronomy, University of Massachusetts, Amherst, MA 01002 (United States); Charmandaris, Vassilis [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003, Heraklion (Greece); Daddi, Emmanuele; Elbaz, David; Pannella, Maurilio; Aussel, Herve; Dasyra, Kalliopi; Leiton, Roger [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Hwang, Ho Seong [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Scott, Douglas; Magnelli, Benjamin; Popesso, Paola [Max-Planck-Institut fuer Extraterrestrische Physik (MPE), Postfach 1312, D-85741, Garching (Germany); Altieri, Bruno; Coia, Daniela; Valtchanov, Ivan [Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Canada, E-28691 Madrid (Spain); Dannerbauer, Helmut [Universitaet Wien, Institut fuer Astrophysik, Tuerkenschanzstrasse 17, A-1180 Wien (Austria); Dickinson, Mark; Kartaltepe, Jeyhan [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Magdis, Georgios [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)

    2013-02-15

    We have compiled a large sample of 151 high-redshift (z = 0.5-4) galaxies selected at 24 {mu}m (S {sub 24} > 100 {mu}Jy) in the GOODS-N and ECDFS fields for which we have deep Spitzer IRS spectroscopy, allowing us to decompose the mid-infrared spectrum into contributions from star formation and activity in the galactic nuclei. In addition, we have a wealth of photometric data from Spitzer IRAC/MIPS and Herschel PACS/SPIRE. We explore how effective different infrared color combinations are at separating our mid-IR spectroscopically determined active galactic nuclei from our star-forming galaxies. We look in depth at existing IRAC color diagnostics, and we explore new color-color diagnostics combining mid-IR, far-IR, and near-IR photometry, since these combinations provide the most detail about the shape of a source's IR spectrum. An added benefit of using a color that combines far-IR and mid-IR photometry is that it is indicative of the power source driving the IR luminosity. For our data set, the optimal color selections are S {sub 250}/S {sub 24} versus S {sub 8}/S {sub 3.6} and S {sub 100}/S {sub 24} versus S {sub 8}/S {sub 3.6}; both diagnostics have {approx}10% contamination rate in the regions occupied primarily by star-forming galaxies and active galactic nuclei, respectively. Based on the low contamination rate, these two new IR color-color diagnostics are ideal for estimating both the mid-IR power source of a galaxy when spectroscopy is unavailable and the dominant power source contributing to the IR luminosity. In the absence of far-IR data, we present color diagnostics using the Wide-field Infrared Survey Explorer mid-IR bands which can efficiently select out high-z (z {approx} 2) star-forming galaxies.

  19. Virtual screening and optimization of Type II inhibitors of JAK2 from a natural product library.

    Science.gov (United States)

    Ma, Dik-Lung; Chan, Daniel Shiu-Hin; Wei, Guo; Zhong, Hai-Jing; Yang, Hui; Leung, Lai To; Gullen, Elizabeth A; Chiu, Pauline; Cheng, Yung-Chi; Leung, Chung-Hang

    2014-11-21

    Amentoflavone has been identified as a JAK2 inhibitor by structure-based virtual screening of a natural product library. In silico optimization using the DOLPHIN model yielded analogues with enhanced potency against JAK2 activity and HCV activity in cellulo. Molecular modeling and kinetic experiments suggested that the analogues may function as Type II inhibitors of JAK2.

  20. The Black Hole Mass-Bulge Luminosity Relationship for Active Galactic Nuclei From Reverberation Mapping and Hubble Space Telescope Imaging

    DEFF Research Database (Denmark)

    Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.

    2009-01-01

    We investigate the relationship between black hole mass and bulge luminosity for active galactic nuclei (AGNs) with reverberation-based black hole mass measurements and bulge luminosities from two-dimensional decompositions of Hubble Space Telescope host galaxy images. We find that the slope...... of the relationship for AGNs is 0.76-0.85 with an uncertainty of ~0.1, somewhat shallower than the M BH vprop L 1.0±0.1 relationship that has been fit to nearby quiescent galaxies with dynamical black hole mass measurements. This difference is somewhat perplexing, as the AGN black hole masses include an overall...

  1. RADIO-LOUD NARROW-LINE SEYFERT 1 AS A NEW CLASS OF GAMMA-RAY ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Cameron, R. A.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bonamente, E.; Brigida, M.; Bruel, P.; Burnett, T. H.; Caliandro, G. A.

    2009-01-01

    We report the discovery with Fermi/LAT of γ-ray emission from three radio-loud narrow-line Seyfert 1 galaxies: PKS 1502+036 (z = 0.409), 1H 0323+342 (z = 0.061), and PKS 2004 - 447 (z = 0.24). In addition to PMN J0948+0022 (z = 0.585), the first source of this type to be detected in γ rays, they may form an emerging new class of γ-ray active galactic nuclei (AGNs). These findings can have strong implications on our knowledge about relativistic jets and the unified model of the AGN.

  2. Galactic models

    International Nuclear Information System (INIS)

    Buchler, J.R.; Gottesman, S.T.; Hunter, J.H. Jr.

    1990-01-01

    Various papers on galactic models are presented. Individual topics addressed include: observations relating to galactic mass distributions; the structure of the Galaxy; mass distribution in spiral galaxies; rotation curves of spiral galaxies in clusters; grand design, multiple arm, and flocculent spiral galaxies; observations of barred spirals; ringed galaxies; elliptical galaxies; the modal approach to models of galaxies; self-consistent models of spiral galaxies; dynamical models of spiral galaxies; N-body models. Also discussed are: two-component models of galaxies; simulations of cloudy, gaseous galactic disks; numerical experiments on the stability of hot stellar systems; instabilities of slowly rotating galaxies; spiral structure as a recurrent instability; model gas flows in selected barred spiral galaxies; bar shapes and orbital stochasticity; three-dimensional models; polar ring galaxies; dynamical models of polar rings

  3. Gonadotropin-releasing hormone type II (GnRH-II) agonist regulates the invasiveness of endometrial cancer cells through the GnRH-I receptor and mitogen-activated protein kinase (MAPK)-dependent activation of matrix metalloproteinase (MMP)-2

    International Nuclear Information System (INIS)

    Wu, Hsien-Ming; Wang, Hsin-Shih; Huang, Hong-Yuan; Lai, Chyong-Huey; Lee, Chyi-Long; Soong, Yung-Kuei; Leung, Peter CK

    2013-01-01

    More than 25% of patients diagnosed with endometrial carcinoma have an invasive primary cancer accompanied by metastases. Gonadotropin-releasing hormone (GnRH) plays an important role in reproduction. In mammals, expression of GnRH-II is higher than GnRH-I in reproductive tissues. Here, we examined the effect of a GnRH-II agonist on the motility of endometrial cancer cells and its mechanism of action in endometrial cancer therapy. Immunoblotting and immunohistochemistry (IHC) were used to determine the expression of the GnRH-I receptor protein in human endometrial cancer. The activity of MMP-2 in the conditioned medium was determined by gelatin zymography. Cell motility was assessed by invasion and migration assay. GnRH-I receptor si-RNA was applied to knockdown GnRH-I receptor. The GnRH-I receptor was expressed in the endometrial cancer cells. The GnRH-II agonist promoted cell motility in a dose-dependent manner. The GnRH-II agonist induced the phosphorylation of ERK1/2 and JNK, and the phosphorylation was abolished by ERK1/2 inhibitor (U0126) and the JNK inhibitor (SP600125). Cell motility promoted by GnRH-II agonist was suppressed in cells that were pretreated with U0126 and SP600125. Moreover, U0126 and SP600125 abolished the GnRH-II agonist-induced activation of MMP-2. The inhibition of MMP-2 with MMP-2 inhibitor (OA-Hy) suppressed the increase in cell motility in response to the GnRH-II agonist. Enhanced cell motility mediated by GnRH-II agonist was also suppressed by the knockdown of the endogenous GnRH-I receptor using siRNA. Our study indicates that GnRH-II agonist promoted cell motility of endometrial cancer cells through the GnRH-I receptor via the phosphorylation of ERK1/2 and JNK, and the subsequent, MAPK-dependent activation of MMP-2. Our findings represent a new concept regarding the mechanism of GnRH-II-induced cell motility in endometrial cancer cells and suggest the possibility of exploring GnRH-II as a potential therapeutic target for the

  4. Changing ionization conditions in SDSS galaxies with active galactic nuclei as a function of environment from pairs to clusters

    International Nuclear Information System (INIS)

    Khabiboulline, Emil T.; Steinhardt, Charles L.; Silverman, John D.; Ellison, Sara L.; Mendel, J. Trevor; Patton, David R.

    2014-01-01

    We study how active galactic nucleus (AGN) activity changes across environments from galaxy pairs to clusters using 143,843 galaxies with z < 0.2 from the Sloan Digital Sky Survey. Using a refined technique, we apply a continuous measure of AGN activity, characteristic of the ionization state of the narrow-line emitting gas. Changes in key emission-line ratios ([N II] λ6548/Hα, [O III] λ5007/Hβ) between different samples allow us to disentangle different environmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole.

  5. Changing ionization conditions in SDSS galaxies with active galactic nuclei as a function of environment from pairs to clusters

    Energy Technology Data Exchange (ETDEWEB)

    Khabiboulline, Emil T.; Steinhardt, Charles L. [California Institute of Technology, 1200 East-California Boulevard, Pasadena, CA 91125 (United States); Silverman, John D. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa-Shi, Chiba 277-8583 (Japan); Ellison, Sara L. [Department of Physics and Astronomy, University of Victoria, Finnerty Road, Victoria, British Columbia, V8P 1A1 (Canada); Mendel, J. Trevor [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching (Germany); Patton, David R., E-mail: ekhabibo@caltech.edu [Department of Physics and Astronomy, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9J 7B8 (Canada)

    2014-11-01

    We study how active galactic nucleus (AGN) activity changes across environments from galaxy pairs to clusters using 143,843 galaxies with z < 0.2 from the Sloan Digital Sky Survey. Using a refined technique, we apply a continuous measure of AGN activity, characteristic of the ionization state of the narrow-line emitting gas. Changes in key emission-line ratios ([N II] λ6548/Hα, [O III] λ5007/Hβ) between different samples allow us to disentangle different environmental effects while removing contamination. We confirm that galaxy interactions enhance AGN activity. However, conditions in the central regions of clusters are inhospitable for AGN activity even if galaxies are in pairs. These results can be explained through models of gas dynamics in which pair interactions stimulate the transfer of gas to the nucleus and clusters suppress gas availability for accretion onto the central black hole.

  6. Chains of N=2, D=4 heterotic type II duals

    CERN Document Server

    Aldazabal, G; Font, A; Quevedo, Fernando

    1996-01-01

    We report on a search for N=2 heterotic strings that are dual candidates of type II compactifications on Calabi-Yau threefolds described as K3 fibrations. We find many new heterotic duals by using standard orbifold techniques. The associated type II compactifications fall into chains in which the proposed duals are heterotic compactifications related one another by a sequential Higgs mechanism. This breaking in the heterotic side typically involves the sequence SU(4)\\rightarrow SU(3)\\rightarrow SU(2)\\rightarrow 0, while in the type II side the weights of the complex hypersurfaces and the structure of the K3 quotient singularities also follow specific patterns.

  7. DISCOVERY OF CANDIDATE H2O DISK MASERS IN ACTIVE GALACTIC NUCLEI AND ESTIMATIONS OF CENTRIPETAL ACCELERATIONS

    International Nuclear Information System (INIS)

    Greenhill, Lincoln J.; Moran, James M.; Tilak, Avanti; Kondratko, Paul T.

    2009-01-01

    Based on spectroscopic signatures, about one-third of known H 2 O maser sources in active galactic nuclei (AGNs) are believed to arise in highly inclined accretion disks around central engines. These 'disk maser candidates' are of interest primarily because angular structure and rotation curves can be resolved with interferometers, enabling dynamical study. We identify five new disk maser candidates in studies with the Green Bank Telescope, bringing the total number published to 30. We discovered two (NGC 1320, NGC 17) in a survey of 40 inclined active galaxies (v sys -1 ). The remaining three disk maser candidates were identified in monitoring of known sources: NGC 449, NGC 2979, and NGC 3735. We also confirm a previously marginal case in UGC 4203. For the disk maser candidates reported here, inferred rotation speeds are 130-500 km s -1 . Monitoring of three more rapidly rotating candidate disks (CG 211, NGC 6264, VV 340A) has enabled measurement of likely orbital centripetal acceleration, and estimation of central masses ((2-7) x10 7 M sun ) and mean disk radii (0.2-0.4 pc). Accelerations may ultimately permit estimation of distances when combined with interferometer data. This is notable because the three AGNs are relatively distant (10,000 km s -1 sys -1 ), and fractional error in a derived Hubble constant, due to peculiar motion of the galaxies, would be small. As signposts of highly inclined geometries at galactocentric radii of ∼0.1-1 pc, disk masers also provide robust orientation references that allow analysis of (mis)alignment between AGNs and surrounding galactic stellar disks, even without extensive interferometric mapping. We find no preference among published disk maser candidates to lie in high-inclination galaxies. This provides independent support for conclusions that in late-type galaxies, central engine accretion disks and galactic plane orientations are not correlated.

  8. EXTENDED X-RAY EMISSION IN THE H I CAVITY OF NGC 4151: GALAXY-SCALE ACTIVE GALACTIC NUCLEUS FEEDBACK?

    International Nuclear Information System (INIS)

    Wang Junfeng; Fabbiano, Giuseppina; Risaliti, Guido; Elvis, Martin; Zezas, Andreas; Mundell, Carole G.; Dumas, Gaelle; Schinnerer, Eva

    2010-01-01

    We present the Chandra discovery of soft diffuse X-ray emission in NGC 4151 (L 0.5-2 k eV ∼ 10 39 erg s -1 ), extending ∼2 kpc from the active nucleus and filling in the cavity of the H I material. The best fit to the X-ray spectrum requires either a kT ∼ 0.25 keV thermal plasma or a photoionized component. In the thermal scenario, hot gas heated by the nuclear outflow would be confined by the thermal pressure of the H I gas and the dynamic pressure of inflowing neutral material in the galactic disk. In the case of photoionization, the nucleus must have experienced an Eddington limit outburst. For both scenarios, the active galactic nucleus (AGN)-host interaction in NGC 4151 must have occurred relatively recently (some 10 4 yr ago). This very short timescale to the last episode of high activity phase may imply such outbursts occupy ∼>1% of AGN lifetime.

  9. THE NEAR-INFRARED CORONAL LINE SPECTRUM OF 54 NEARBY ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Rodríguez-Ardila, A.; Prieto, M. A.; Portilla, J. G.; Tejeiro, J. M.

    2011-01-01

    The relationship between the emission of coronal lines (CLs) and nuclear activity in 36 Type 1 and 18 Type 2 active galactic nuclei (AGNs) is analyzed, for the first time, based on near-infrared (0.8-2.4 μm) spectra. The eight CLs studied, of Si, S, Fe, Al, and Ca elements and corresponding to ionization potentials (IPs) in the range 125-450 eV, are detected (3σ) in 67% (36 AGNs) of the sample. Our analysis shows that the four most frequent CLs [Si VI] 1.963 μm, [S VIII] 0.9913 μm, [S IX] 1.252 μm, and [Si X] 1.430 μm display a narrow range in luminosity, with most lines located in the interval log L 39-40 erg s –1 . We found that the non-detection is largely associated with either loss of spatial resolution or increasing object distance: CLs are essentially nuclear and easily lose contrast in the continuum stellar light for nearby sources or get diluted by the strong AGN continuum as the redshift increases. Yet, there are AGNs where the lack of coronal emission, i.e., lines with IP ≥ 100 eV, may be genuine. The absence of these lines reflects a non-standard AGN ionizing continuum, namely, a very hard spectrum lacking photons below a few Kev. The analysis of the line profiles points out a trend of increasing FWHM with increasing IPs up to energies around 300 eV, where a maximum in the FWHM is reached. For higher IP lines, the FWHM remains nearly constant or decreases with increasing IPs. We ascribe this effect to an increasing density environment as we approach the innermost regions of these AGNs, where densities above the critical density of the CLs with IPs larger than 300 eV are reached. This sets a strict range limit for the density in the boundary region between the narrow and the broad region of 10 8 -10 9 cm –3 . A relationship between the luminosity of the CLs and that of the soft and hard X-ray emission and the soft X-ray photon index is observed: the coronal emission becomes stronger with both increasing X-ray emission (soft and hard) and

  10. Cosmological Studies with Galaxy Clusters, Active Galactic Nuclei, and Strongly Lensed Quasars

    Science.gov (United States)

    Rumbaugh, Nicholas Andrew

    The large-scale structure (LSS) of the universe provides scientists with one of the best laboratories for studying Lambda Cold Dark Matter (LambdaCDM) cosmology. Especially at high redshift, we see increased rates of galaxy cluster and galaxy merging in LSS relative to the field, which is useful for studying the hierarchical merging predicted by LambdaCDM. The largest identified bound structures, superclusters, have not yet virialized. Despite the wide range of dynamical states of their constituent galaxies, groups, and clusters, they are all still actively evolving, providing an ideal laboratory in which to study cluster and galaxy evolution. In this dissertation, I present original research on several aspects of LSS and LambdaCDM cosmology. Three separate studies are included, each one focusing on a different aspect. In the first study, we use X-ray and optical observations from nine galaxy clusters at high redshift, some embedded in larger structures and some isolated, to study their evolutionary states. We extract X-ray gas temperatures and luminosities as well as optical velocity dispersions. These cluster properties are compared using low-redshift scaling relations. In addition, we employ several tests of substructure, using velocity histograms, Dressler-Shectman tests, and centroiding offsets. We conclude that two clusters out of our sample are most likely unrelaxed, and find support for deviations from self-similarity in the redshift evolution of the Lx-T relation. Our numerous complementary tests of the evolutionary state of clusters suggest potential under-estimations of systematic error in studies employing only a single such test. In the second study, we use multi-band imaging and spectroscopy to study active galactic nuclei (AGN) in high-redshift LSS. The AGN were identified using X-ray imaging and matched to optical catalogs that contained spectroscopic redshifts to identify members of the structures. AGN host galaxies tended to be associated with the

  11. Synthesis of 3-alkyl enol mimics inhibitors of type II dehydroquinase: factors influencing their inhibition potency.

    Science.gov (United States)

    Blanco, Beatriz; Sedes, Antía; Peón, Antonio; Lamb, Heather; Hawkins, Alastair R; Castedo, Luis; González-Bello, Concepción

    2012-05-14

    Several 3-alkylaryl mimics of the enol intermediate in the reaction catalyzed by type II dehydroquinase were synthesized to investigate the effect on the inhibition potency of replacing the oxygen atom in the side chain by a carbon atom. The length and the rigidity of the spacer was also studied. The inhibitory properties of the reported compounds against type II dehydroquinase from Mycobacterium tuberculosis and Helicobacter pylori are also reported. The binding modes of these analogs in the active site of both enzymes were studied by molecular docking using GOLD 5.0 and dynamic simulations studies.

  12. Crosstalk between type II NKT cells and T cells leads to spontaneous chronic inflammatory liver disease.

    Science.gov (United States)

    Weng, Xiufang; He, Ying; Visvabharathy, Lavanya; Liao, Chia-Min; Tan, Xiaosheng; Balakumar, Arjun; Wang, Chyung-Ru

    2017-10-01

    Natural killer T (NKT) cells are CD1d-restricted innate-like T cells that modulate innate and adaptive immune responses. Unlike the well-characterized invariant/type I NKT cells, type II NKT cells with a diverse T cell receptor repertoire are poorly understood. This study defines the pathogenic role of type II NKT cells in the etiology of chronic liver inflammation. Transgenic mice with the Lck promoter directing CD1d overexpression on T cells in Jα18 wild-type (Lck-CD1dTgJα18 + ; type I NKT cell sufficient) and Jα18-deficient (Lck-CD1dTgJα18 o , type I NKT cell deficient) mice were analyzed for liver pathology and crosstalk between type II NKT cells and conventional T cells. CD1d expression on T cells in peripheral blood samples and liver sections from autoimmune hepatitis patients and healthy individuals were also examined. Lck-CD1dTgJα18 o and Lck-CD1dTgJα18 + mice developed similar degrees of liver pathology resembling chronic autoimmune hepatitis in humans. Increased CD1d expression on T cells promoted the activation of type II NKT cells and other T cells. This resulted in T h 1-skewing and impaired T h 2 cytokine production in type II NKT cells. Dysfunction of type II NKT cells was accompanied by conventional T cell activation and pro-inflammatory cytokine production, leading to a hepatic T/B lymphocyte infiltration, elevated autoantibodies and hepatic injury in Lck-CD1dTg mice. A similar mechanism could be extended to humans as CD1d expression is upregulated on activated human T cells and increased presence of CD1d-expressing T cells was observed in autoimmune hepatitis patients. Our data reveals enhanced crosstalk between type II NKT cells and conventional T cells, leading to a T h 1-skewed inflammatory milieu, and consequently, to the development of chronic autoimmune liver disease. Lay summary: CD1d overexpression on T cells enhances crosstalk between type II NKT cells and T cells, resulting in their aberrant activation and leading to the

  13. Electrodiagnostic evaluation of median nerve conduction in Type II ...

    African Journals Online (AJOL)

    MJP

    2015-12-29

    Dec 29, 2015 ... Type II diabetes mellitus patients that were asymptomatic for peripheral neuropathy: a case control study. Owolabi LF 1*, Adebisi S2, ... degree of abnormality and monitoring the clinical course of the disease. Symptoms of DN ...

  14. Cardiovascular risk markers in type II diabetes and hypertension at ...

    African Journals Online (AJOL)

    Cardiovascular risk markers in type II diabetes and hypertension at the Battor Catholic ... either precedes or is a consequence of the development of these diseases. ... The control group consisted of 62 age-matched healthy individuals.

  15. The decline and fall of Type II error rates

    Science.gov (United States)

    Steve Verrill; Mark Durst

    2005-01-01

    For general linear models with normally distributed random errors, the probability of a Type II error decreases exponentially as a function of sample size. This potentially rapid decline reemphasizes the importance of performing power calculations.

  16. CT appearance of liver and gallbladder in type II diabetics

    International Nuclear Information System (INIS)

    Li Jingshan; Li Wei; Zhang Yuzhong; Zhao Xiuyi; Zhang Xuelin

    2005-01-01

    Objective: To evaluate CT findings of liver and gallbladder in type II diabetics and to discuss diabetic, and investigate the correlation between type II diabetics, and investigate the correlation between the diabetes and the lesions found in the liver or gallbladder. Methods: Retrospective analysis was made on the CT findings of hepatic and gallbladder lesions in 586 cases of II diabetes. Results: In total 586 type II diabetics, cholecystitis and/or gallstone were revealed in 33.45% patients; and hepatic alteration was noted in 20.48% cases. Hepatic abnormalities were found in 58.67% cases in the cholecystitis/gallstone group, significantly different from the group with unremarkable gallbladder, in which hepatic lesions were found only in 1.28% cases. Conclusion: The hepatic alteration is secondary to the gallbladder lesions in type II diabetics. (authors)

  17. MOJAVE. X. PARSEC-SCALE JET ORIENTATION VARIATIONS AND SUPERLUMINAL MOTION IN ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Lister, M. L.; Richards, J. L. [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Aller, M. F.; Aller, H. D. [Department of Astronomy, University of Michigan, 817 Dennison Building, Ann Arbor, MI 48109 (United States); Homan, D. C. [Department of Physics, Denison University, Granville, OH 43023 (United States); Kellermann, K. I. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Kovalev, Y. Y. [Astro Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, 117997 Moscow (Russian Federation); Pushkarev, A. B.; Ros, E.; Savolainen, T., E-mail: mlister@purdue.edu [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2013-11-01

    We describe the parsec-scale kinematics of 200 active galactic nucleus (AGN) jets based on 15 GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2011 May 1. We present new VLBA 15 GHz images of these and 59 additional AGNs from the MOJAVE and 2 cm Survey programs. Nearly all of the 60 most heavily observed jets show significant changes in their innermost position angle over a 12-16 yr interval, ranging from 10° to 150° on the sky, corresponding to intrinsic variations of ∼0.°5 to ∼2°. The BL Lac jets show smaller variations than quasars. Roughly half of the heavily observed jets show systematic position angle trends with time, and 20 show indications of oscillatory behavior. The time spans of the data sets are too short compared to the fitted periods (5-12 yr), however, to reliably establish periodicity. The rapid changes and large jumps in position angle seen in many cases suggest that the superluminal AGN jet features occupy only a portion of the entire jet cross section and may be energized portions of thin instability structures within the jet. We have derived vector proper motions for 887 moving features in 200 jets having at least five VLBA epochs. For 557 well-sampled features, there are sufficient data to additionally study possible accelerations. We find that the moving features are generally non-ballistic, with 70% of the well-sampled features showing either significant accelerations or non-radial motions. Inward motions are rare (2% of all features), are slow (<0.1 mas yr{sup –1}), are more prevalent in BL Lac jets, and are typically found within 1 mas of the unresolved core feature. There is a general trend of increasing apparent speed with distance down the jet for both radio galaxies and BL Lac objects. In most jets, the speeds of the features cluster around a characteristic value, yet there is a considerable dispersion in the distribution. Orientation variations within the jet cannot fully account for the

  18. Duality symmetries and the Type II string effective action

    International Nuclear Information System (INIS)

    Bergshoeff, E.

    1996-01-01

    We discuss the duality symmetries of Type II string effective actions in nine, ten and eleven dimensions. As a by-product we give a covariant action underlying the ten-dimensional Type IIB supergravity theory. We apply duality symmetries to construct dyonic Type II string solutions in six dimensions and their reformulation as solutions of the ten-dimensional Type IIB theory in ten dimensions. (orig.)

  19. Mutation and biochemical analysis in carnitine palmitoyltransferase type II (CPT II) deficiency

    DEFF Research Database (Denmark)

    Olpin, S E; Afifi, A; Clark, S

    2003-01-01

    Carnitine palmitoyltransferase type II (CPT II) deficiency has three basic phenotypes, late-onset muscular (mild), infantile/juvenile hepatic (intermediate) and severe neonatal. We have measured fatty acid oxidation and CPT II activity and performed mutation studies in 24 symptomatic patients...

  20. Comparison of Diabetes Type II Patients Life Style Effective Factors With That of Healthy People.

    Directory of Open Access Journals (Sweden)

    D Mostafaei

    2008-07-01

    Full Text Available Introduction:Diabetes is a significant and expensive health problem which had influenced all the ages in almost all the countries. Increasing prevalence of this disease has been caused by continued changes in lifestyle such as unsuitable nutrition, lack of physical activities and fatness which is often related to modern city life, mechanization and industrialization. It is an expensive disease, both for patients and the health and hygienic care systems. This research tried to examine the relationship between lifestyle risk factors and type II diabetes. Methods: This research was a case-control type by random sampling and studying140 diabetes type II patients as case group and 140 healthy people accompanying some other patients as the control group at Tonekabon Shahid Rajaei hospital. People were of both sexes, between 30 and 64 years of age and Tonekabon residents. The questionnaire used included demographic, nutritional, physical activities, stress tolerance and smoking status information. The SPSS 11.5 and excel software were used for statistic calculation and for analysis of data, T and Chi-Square tests were applied. Results: By analyzing the data collected, there was a meaningful statistical relationship between physical activities, stress residence, nutrition, smoking and the diabetes type II disease (P-value0.05. Conclusion: Results imply that some risk factors important in diabetes type II include unsuitable nutrition such as having too much of sweets and sugar,lack of fruits, vegetables, fish, proteins and also lack of physical activities, stress tolerance and control.

  1. Unification of Active Galactic Nuclei at X-rays and soft gamma-rays

    International Nuclear Information System (INIS)

    Beckmann, Volker

    2010-01-01

    Through the work on X-ray and gamma-ray data of AGN I contributed significantly to the progress in the unification of AGN since I finished my PhD in 2000. The study of the evolutionary behaviour of X-ray selected N blazars (Beckmann and Wolter 2001; Beckmann et al. 2002, 2003b; Beckmann 2003) shows that their evolution is not as strongly negative as indicated by previous studies. The overall luminosity function is consistent with no evolution in the 0.1-2.4 keV band as seen by ROSAT/PSPC. There is still a difference compared to the luminosity function of FSRQ and LBL, which seem to show a positive evolution, indicating that they have been more luminous and/or numerous at cosmological distances. We indicated a scenario in order to explain this discrepancy, in which the high luminous FSRQ develop into the fainter LBL and finally into the BL Lac objects with high frequency peaks in their spectral energy distribution but overall low bolometric luminosity. Studying the variability pattern of hard X-ray selected Seyfert galaxies, we actually found differences between type 1 and type 2 objects, in the sense that type 2 seemed to be more variable (Beckmann et al. 2007a). This breaking of the unified model is caused by the different average luminosity of the absorbed and unabsorbed sources, as discussed in Sect. 4.7.3. This can be explained by a larger inner disk radius when the AGN core is most active (the so-called receding disc model). The work on the sample characteristics of hard X-ray detected AGN also led to the proof that the average intrinsic spectra of type 1 and type 2 objects are the same when reflection processes are taken into account (Beckmann et al. 2009d). This also explains why in the past Seyfert 2 objects were seen to have harder X-ray spectra than Seyfert 1, as the stronger reflection hump in the type 2 objects makes the spectra appear to be flatter, although the underlying continuum is the same. Further strong evidence for the unification scheme comes

  2. Balneotherapy and platelet glutathione metabolism in type II diabetic patients

    Science.gov (United States)

    Ohtsuka, Yoshinori; Yabunaka, Noriyuki; Watanabe, Ichiro; Noro, Hiroshi; Agishi, Yuko

    1996-09-01

    Effects of balneotherapy on platelet glutathione metabolism were investigated in 12 type II (non-insulin-dependent) diabetic patients. Levels of the reduced form of glutathione (GSH) on admission were well correlated with those of fasting plasma glucose (FPG; r=0.692, Pbalneotherapy, the mean level of GSH showed no changes; however, in well-controlled patients (FPG 150 mg/dl), the value decreased ( Pbalneotherapy, the activity increased in 5 patients, decreased in 3 patients and showed no changes (alteration within ±3%) in all the other patients. From these findings in diabetic patients we concluded: (1) platelet GSH synthesis appeared to be induced in response to oxidative stress; (2) lowered GPX activities indicated that the antioxidative defense system was impaired; and (3) platelet glutathione metabolism was partially improved by 4 weeks balneotherapy, an effect thought to be dependent on the control status of plasma glucose levels. It is suggested that balneotherapy is beneficial for patients whose platelet antioxidative defense system is damaged, such as those with diabetes mellitus and coronary heart disease.

  3. Psycho-neuro-endocrine-immune mechanisms of action of yoga in type II diabetes.

    Science.gov (United States)

    Singh, Vijay Pratap; Khandelwal, Bidita; Sherpa, Namgyal T

    2015-01-01

    Yoga has been found to benefit all the components of health viz. physical, mental, social and spiritual well being by incorporating a wide variety of practices. Pathophysiology of Type II DM and co-morbidities in Type II DM has been correlated with stress mechanisms. Stress suppresses body's immune system and neuro-humoral actions thereby aff ecting normal psychological state. It would not be wrong to state that correlation of diabetes with stress, anxiety and other psychological factors are bidirectional and lead to difficulty in understanding the interrelated mechanisms. Type II DM cannot be understood in isolation with psychological factors such as stress, anxiety and depression, neuro-endocrine and immunological factors. There is no review which tries to understand these mechanisms exclusively. The present literature review aims to understand interrelated Psycho-Neuro-Endocrine and Immunological mechanisms of action of Yoga in Type II Diabetes Mellitus. Published literature concerning mechanisms of action of Yoga in Type II DM emphasizing psycho-neuro-endocrine or immunological relations was retrieved from Pubmed using key words yoga, Type II diabetes mellitus, psychological, neural, endocrine, immune and mechanism of action. Those studies which explained the psycho-neuroendocrine and immune mechanisms of action of yoga were included and rest were excluded. Although primary aim of this study is to explain these mechanisms in Type II DM, some studies in non-diabetic population which had a similar pathway of stress mechanism was included because many insightful studies were available in that area. Search was conducted using terms yoga OR yogic AND diabetes OR diabetic IN title OR abstract for English articles. Of the 89 articles, we excluded non-English articles (22), editorials (20) and letters to editor (10). 37 studies were considered for this review. The postulated mechanism of action of yoga is through parasympathetic activation and the associated anti

  4. Methodological studies on the search for Gravitational Waves and Neutrinos from Type II Supernovae

    International Nuclear Information System (INIS)

    Casentini, Claudio

    2016-01-01

    Type II SNe, also called Core-collapse SuperNovae have a neutrino (v) emission, as confirmed by SN 1987A, and are also potential sources of gravitational waves. Neutrinos and gravitational waves from these sources reach Earth almost contemporaneously and without relevant interaction with stellar matter and interstellar medium. The upcoming advanced gravitational interferometers would be sensitive enough to detect gravitational waves signals from close galactic Core-collapse SuperNovae events. Nevertheless, significant uncertainties on theoretical models of emission remain. A joint search of coincident low energy neutrinos and gravitational waves events from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent SuperNovae. Recently a project for a joint search involving gravitational wave interferometers and neutrino detectors has started. We discuss the benefits of a joint search and the status of the search project. (paper)

  5. GOODS-HERSCHEL: IMPACT OF ACTIVE GALACTIC NUCLEI AND STAR FORMATION ACTIVITY ON INFRARED SPECTRAL ENERGY DISTRIBUTIONS AT HIGH REDSHIFT

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, Allison; Pope, Alexandra [Department of Astronomy, University of Massachusetts, Amherst, MA 01002 (United States); Alexander, David M. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Charmandaris, Vassilis [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003, Heraklion (Greece); Daddi, Emmanuele; Elbaz, David; Gabor, Jared; Mullaney, James; Pannella, Maurilio; Aussel, Herve; Bournaud, Frederic; Dasyra, Kalliopi [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Dickinson, Mark [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Hwang, Ho Seong [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Ivison, Rob [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Altieri, Bruno; Coia, Daniela [Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Canada, E-28691 Madrid (Spain); Buat, Veronique [Laboratoire d' Astrophysique de Marseille (LAM), Universite d' Aix-Marseille, CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Dannerbauer, Helmut, E-mail: kirkpatr@astro.umass.edu [Institut fuer Astrophysik, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180 Wien (Austria); and others

    2012-11-10

    We explore the effects of active galactic nuclei (AGNs) and star formation activity on the infrared (0.3-1000 {mu}m) spectral energy distributions (SEDs) of luminous infrared galaxies from z = 0.5 to 4.0. We have compiled a large sample of 151 galaxies selected at 24 {mu}m (S {sub 24} {approx}> 100 {mu}Jy) in the GOODS-N and ECDFS fields for which we have deep Spitzer IRS spectroscopy, allowing us to decompose the mid-IR spectrum into contributions from star formation and AGN activity. A significant portion ({approx}25%) of our sample is dominated by an AGN (>50% of the mid-IR luminosity) in the mid-IR. Based on the mid-IR classification, we divide our full sample into four sub-samples: z {approx} 1 star-forming (SF) sources, z {approx} 2 SF sources, AGNs with clear 9.7 {mu}m silicate absorption, and AGNs with featureless mid-IR spectra. From our large spectroscopic sample and wealth of multi-wavelength data, including deep Herschel imaging at 100, 160, 250, 350, and 500 {mu}m, we use 95 galaxies with complete spectral coverage to create a composite SED for each sub-sample. We then fit a two-temperature component modified blackbody to the SEDs. We find that the IR SEDs have similar cold dust temperatures, regardless of the mid-IR power source, but display a marked difference in the warmer dust temperatures. We calculate the average effective temperature of the dust in each sub-sample and find a significant ({approx}20 K) difference between the SF and AGN systems. We compare our composite SEDs to local templates and find that local templates do not accurately reproduce the mid-IR features and dust temperatures of our high-redshift systems. High-redshift IR luminous galaxies contain significantly more cool dust than their local counterparts. We find that a full suite of photometry spanning the IR peak is necessary to accurately account for the dominant dust temperature components in high-redshift IR luminous galaxies.

  6. The Adaptor Protein SAP Regulates Type II NKT Cell Development, Cytokine Production and Cytotoxicity Against Lymphoma1

    Science.gov (United States)

    Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya; Cardell, Susanna L.; Stein, Paul L.; Wang, Chyung-Ru

    2014-01-01

    CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule-associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT cell TCR transgenic mouse model (24αβTg), we demonstrated that CD1d-expressing hematopoietic cells but not thymic epithelial cells meditate efficient selection of type II NKT cells. Further, we showed that SAP regulates type II NKT cell development by controlling Egr2 and PLZF expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IRF4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP. PMID:25236978

  7. Ca(2+) currents and voltage responses in Type I and Type II hair cells of the chick embryo semicircular canal.

    Science.gov (United States)

    Masetto, Sergio; Zampini, Valeria; Zucca, Giampiero; Valli, Paolo

    2005-11-01

    Type I and Type II hair cells, and Type II hair cells located in different zones of the semicircular canal crista, express different patterns of voltage-dependent K channels, each one specifically shaping the hair cell receptor potential. We report here that, close to hatching, chicken embryo semicircular canal Type I and Type II hair cells express a similar voltage-dependent L-type calcium current (I(Ca)), whose main features are: activation above -60 mV, fast activation kinetics, and scarce inactivation. I(Ca) should be already active at rest in Zone 1 Type II hair cells, whose resting membrane potential was on average slightly less negative than -60 mV. Conversely, I(Ca) would not be active at rest in Type II hair cells from Zone 2 and 3, nor in Type I hair cells, since their resting membrane potential was significantly more negative than -60 mV. However, even small depolarising currents would activate I(Ca) steadily in Zone 2 and 3 Type II hair cells, but not in Type I hair cells because of the robust repolarising action of their specific array of K(+) currents. The implications of the present findings in the afferent discharge are discussed.

  8. A CLOSER VIEW OF THE RADIO-FIR CORRELATION: DISENTANGLING THE CONTRIBUTIONS OF STAR FORMATION AND ACTIVE GALACTIC NUCLEUS ACTIVITY

    International Nuclear Information System (INIS)

    Moric, I.; Smolcic, V.; Riechers, D. A.; Scoville, N.; Kimball, A.; Ivezic, Z.

    2010-01-01

    We extend the Unified Radio Catalog, a catalog of sources detected by various (NVSS, FIRST, WENSS, GB6) radio surveys, and SDSS, to IR wavelengths by matching it to the IRAS Point and Faint Source catalogs. By fitting each NVSS-selected galaxy's NUV-NIR spectral energy distribution (SED) with stellar population synthesis models we add to the catalog star formation rates (SFRs), stellar masses, and attenuations. We further add information about optical emission-line properties for NVSS-selected galaxies with available SDSS spectroscopy. Using an NVSS 20 cm (F 1.4 G Hz ∼> 2.5 mJy) selected sample, matched to the SDSS spectroscopic ('main' galaxy and quasar) catalogs and IRAS data (0.04 < z ∼< 0.2) we perform an in-depth analysis of the radio-FIR correlation for various types of galaxies, separated into (1) quasars, (2) star-forming, (3) composite, (4) Seyfert, (5) LINER, and (6) absorption line galaxies using the standard optical spectroscopic diagnostic tools. We utilize SED-based SFRs to independently quantify the source of radio and FIR emission in our galaxies. Our results show that Seyfert galaxies have FIR/radio ratios lower than, but still within the scatter of, the canonical value due to an additional (likely active galactic nucleus (AGN)) contribution to their radio continuum emission. Furthermore, IR-detected absorption and LINER galaxies are on average strongly dominated by AGN activity in both their FIR and radio emission; however their average FIR/radio ratio is consistent with that expected for star-forming galaxies. In summary, we find that most AGN-containing galaxies in our NVSS-IRAS-SDSS sample have FIR/radio flux ratios indistinguishable from those of the star-forming galaxies that define the radio-FIR correlation. Thus, attempts to separate AGNs from star-forming galaxies by their FIR/radio flux ratios alone can separate only a small fraction of the AGNs, such as the radio-loud quasars.

  9. Endoribonuclease type II toxin-antitoxin systems: functional or selfish?

    Science.gov (United States)

    Ramisetty, Bhaskar Chandra Mohan; Santhosh, Ramachandran Sarojini

    2017-07-01

    Most bacterial genomes have multiple type II toxin-antitoxin systems (TAs) that encode two proteins which are referred to as a toxin and an antitoxin. Toxins inhibit a cellular process, while the interaction of the antitoxin with the toxin attenuates the toxin's activity. Endoribonuclease-encoding TAs cleave RNA in a sequence-dependent fashion, resulting in translational inhibition. To account for their prevalence and retention by bacterial genomes, TAs are credited with clinically significant phenomena, such as bacterial programmed cell death, persistence, biofilms and anti-addiction to plasmids. However, the programmed cell death and persistence hypotheses have been challenged because of conceptual, methodological and/or strain issues. In an alternative view, chromosomal TAs seem to be retained by virtue of addiction at two levels: via a poison-antidote combination (TA proteins) and via transcriptional reprogramming of the downstream core gene (due to integration). Any perturbation in the chromosomal TA operons could cause fitness loss due to polar effects on the downstream genes and hence be detrimental under natural conditions. The endoribonucleases encoding chromosomal TAs are most likely selfish DNA as they are retained by bacterial genomes, even though TAs do not confer a direct advantage via the TA proteins. TAs are likely used by various replicons as 'genetic arms' that allow the maintenance of themselves and associated genetic elements. TAs seem to be the 'selfish arms' that make the best use of the 'arms race' between bacterial genomes and plasmids.

  10. Simvastatin enhances bone morphogenetic protein receptor type II expression

    International Nuclear Information System (INIS)

    Hu Hong; Sung, Arthur; Zhao, Guohua; Shi, Lingfang; Qiu Daoming; Nishimura, Toshihiko; Kao, Peter N.

    2006-01-01

    Statins confer therapeutic benefits in systemic and pulmonary vascular diseases. Bone morphogenetic protein (BMP) receptors serve essential signaling functions in cardiovascular development and skeletal morphogenesis. Mutations in BMP receptor type II (BMPR2) are associated with human familial and idiopathic pulmonary arterial hypertension, and pathologic neointimal proliferation of vascular endothelial and smooth muscle cells within small pulmonary arteries. In severe experimental pulmonary hypertension, simvastatin reversed disease and conferred a 100% survival advantage. Here, modulation of BMPR2 gene expression by simvastatin is characterized in human embryonic kidney (HEK) 293T, pulmonary artery smooth muscle, and lung microvascular endothelial cells (HLMVECs). A 1.4 kb BMPR2 promoter containing Egr-1 binding sites confers reporter gene activation in 293T cells which is partially inhibited by simvastatin. Simvastatin enhances steady-state BMPR2 mRNA and protein expression in HLMVEC, through posttranscriptional mRNA stabilization. Simvastatin induction of BMPR2 expression may improve BMP-BMPR2 signaling thereby enhancing endothelial differentiation and function

  11. Enhanced Materials Based on Submonolayer Type-II Quantum Dots

    Energy Technology Data Exchange (ETDEWEB)

    Tamargo, Maria C [City College of New York, NY (United States); Kuskovsky, Igor L. [City Univ. (CUNY), NY (United States) Queens College; Meriles, Carlos [City College of New York, NY (United States); Noyan, Ismail C. [Columbia Univ., New York, NY (United States)

    2017-04-15

    We have investigated a nanostructured material known as sub-monolayer type-II QDs, made from wide bandgap II-VI semiconductors. Our goal is to understand and exploit their tunable optical and electrical properties by taking advantage of the type-II band alignment and quantum confinement effects. Type-II ZnTe quantum dots (QDs) in a ZnSe host are particularly interesting because of their relatively large valence band and conduction band offsets. In the current award we have developed new materials based on sub-monolayer type-II QDs that may be advantageous for photovoltaic and spintronics applications. We have also expanded the structural characterization of these materials by refining the X-ray diffraction methodologies needed to investigate them. In particular, we have 1) demonstrated ZnCdTe/ZnCdSe type-II QDs materials that have ideal properties for the development of novel high efficiency “intermediate band solar cells”, 2) we developed a comprehensive approach to describe and model the growth of these ultra-small type-II QDs, 3) analysis of the evolution of the photoluminescence (PL) emission, combined with other characterization probes allowed us to predict the size and density of the QDs as a function of the growth conditions, 4) we developed and implemented novel sophisticated X-ray diffraction techniques from which accurate size and shape of the buried type-II QDs could be extracted, 5) a correlation of the shape anisotropy with polarization dependent PL was observed, confirming the QDs detailed shape and providing insight about the effects of this shape anisotropy on the physical properties of the type-II QD systems, and 6) a detailed “time-resolved Kerr rotation” investigation has led to the demonstration of enhanced electron spin lifetimes for the samples with large densities of type-II QDs and an understanding of the interplay between the QDs and Te-isoelectroic centers, a defect that forms in the spacer layers that separate the QDs.

  12. Anomalous Nernst effect in type-II Weyl semimetals

    Science.gov (United States)

    Saha, Subhodip; Tewari, Sumanta

    2018-01-01

    Topological Weyl semimetals (WSM), a new state of quantum matter with gapless nodal bulk spectrum and open Fermi arc surface states, have recently sparked enormous interest in condensed matter physics. Based on the symmetry and fermiology, it has been proposed that WSMs can be broadly classified into two types, type-I and type-II Weyl semimetals. While the undoped, conventional, type-I WSMs have point like Fermi surface and vanishing density of states (DOS) at the Fermi energy, the type-II Weyl semimetals break Lorentz symmetry explicitly and have tilted conical spectra with electron and hole pockets producing finite DOS at the Fermi level. The tilted conical spectrum and finite DOS at Fermi level in type-II WSMs have recently been shown to produce interesting effects such as a chiral anomaly induced longitudinal magnetoresistance that is strongly anisotropic in direction and a novel anomalous Hall effect. In this work, we consider the anomalous Nernst effect in type-II WSMs in the absence of an external magnetic field using the framework of semi-classical Boltzmann theory. Based on both a linearized model of time-reversal breaking WSM with a higher energy cut-off and a more realistic lattice model, we show that the anomalous Nernst response in these systems is strongly anisotropic in space, and can serve as a reliable signature of type-II Weyl semimetals in a host of magnetic systems with spontaneously broken time reversal symmetry.

  13. Prevalence of Gastroesophageal Reflux Disease in Type II Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Huihui Sun

    2014-01-01

    Full Text Available Background/Aims. Patients with type II diabetes mellitus (DM were known to have higher prevalence of gastroesophageal reflux disease (GERD in the Western countries, but data on the impact of GERD on DM patients in our country are scarce. The aim of this study was to evaluate the prevalence of GERD in type II DM patients in Shanghai, China, and to explore its possible risk factors. Methods. 775 type II DM cases were randomly collected. Reflux Disease Questionnaire (RDQ was used to check the presence of GERD. Patients’ characteristics, laboratory data, face-to-face interview, nerve conduction study, and needle electromyogram (EMG test were analyzed. Results. 16% patients were found with typical GERD symptoms. Pathophysiological factors such as peripheral neuropathy, metabolism syndrome, and obesity were found to have no significant differences between GERD and non-GERD type II DM patients in the present study. Conclusion. The prevalence of GERD in type II DM patients is higher than that in adult inhabitants in Shanghai, China. No difference in pathophysiological factors, such as peripheral neuropathy, and metabolism syndrome was found in DM-GERD patients, suggesting that further study and efforts are needed to explore deeper the potential risk factors for the high prevalence rate of GERD in DM patients.

  14. A Statistical Study of Interplanetary Type II Bursts: STEREO Observations

    Science.gov (United States)

    Krupar, V.; Eastwood, J. P.; Magdalenic, J.; Gopalswamy, N.; Kruparova, O.; Szabo, A.

    2017-12-01

    Coronal mass ejections (CMEs) are the primary cause of the most severe and disruptive space weather events such as solar energetic particle (SEP) events and geomagnetic storms at Earth. Interplanetary type II bursts are generated via the plasma emission mechanism by energetic electrons accelerated at CME-driven shock waves and hence identify CMEs that potentially cause space weather impact. As CMEs propagate outward from the Sun, radio emissions are generated at progressively at lower frequencies corresponding to a decreasing ambient solar wind plasma density. We have performed a statistical study of 153 interplanetary type II bursts observed by the two STEREO spacecraft between March 2008 and August 2014. These events have been correlated with manually-identified CMEs contained in the Heliospheric Cataloguing, Analysis and Techniques Service (HELCATS) catalogue. Our results confirm that faster CMEs are more likely to produce interplanetary type II radio bursts. We have compared observed frequency drifts with white-light observations to estimate angular deviations of type II burst propagation directions from radial. We have found that interplanetary type II bursts preferably arise from CME flanks. Finally, we discuss a visibility of radio emissions in relation to the CME propagation direction.

  15. Plasma leptin concentrations are greater in type II diabetic patients and stimulate monocyte chemotactic peptide-1 synthesis via the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway

    Directory of Open Access Journals (Sweden)

    Jin Joo Cha

    2012-09-01

    Conclusions: Overall, these findings suggest that activation of leptin synthesis may promote MCP-1 activation in a diabetic environment via the MAPK pathway in VSMCs and that it possibly contributes to the acceleration of atherosclerosis.

  16. The first IRAM/PdBI polarimetric millimeter survey of active galactic nuclei. II. Activity and properties of individual sources

    Science.gov (United States)

    Trippe, S.; Neri, R.; Krips, M.; Castro-Carrizo, A.; Bremer, M.; Piétu, V.; Winters, J. M.

    2012-04-01

    We present an analysis of the linear polarization of six active galactic nuclei - 0415+379 (3C 111), 0507+179, 0528+134 (OG+134), 0954+658, 1418+546 (OQ+530), and 1637+574 (OS+562). Our targets were monitored from 2007 to 2011 in the observatory-frame frequency range 80-253 GHz, corresponding to a rest-frame frequency range 88-705 GHz. We find average degrees of polarization mL ≈ 2 - 7%; this indicates that the polarization signals are effectively averaged out by the emitter geometries. From a comparison of the fluctuation rates in flux and degree of polarization we conclude that the spatial scales relevant for polarized emission are of the same order of, but probably not smaller than, the spatial scales relevant for the emission of the total flux. We see indication for fairly strong shocks and/or complex, variable emission region geometries in our sources, with compression factors ≲ 0.9 and/or changes in viewing angles by ≳ 10°. An analysis of correlations between source fluxes and polarization parameter points out special cases: the presence of (at least) two distinct emission regions with different levels of polarization (for 0415+379) as well as emission from a single, predominant component (for 0507+179 and 1418+546). Regarding the evolution of flux and polarization, we find good agreement between observations and the signal predicted by "oblique shock in jet" scenarios in one source (1418+546). We attempt to derive rotation measures for all sources, leading to actual measurements for two AGN and upper limits for three sources. We derive values of RM = (-39 ± 1stat ± 13sys) × 103 rad m-2 and RM = (42 ± 1stat ± 11sys) × 104 rad m-2 for 1418+546 and 1637+574, respectively; these are the highest values reported to date for AGN. These values indicate magnetic field strengths of the order ~10-4 G. For 0415+379, 0507+179, and 0954+658 we derive upper limits |RM| < 1.7 × 104 rad m-2. From the relation |RM| ∝ νa we find a = 1.9 ± 0.3 for 1418+546, in

  17. Structural and Molecular Properties of Insect Type II Motor Axon Terminals

    Directory of Open Access Journals (Sweden)

    Bettina Stocker

    2018-03-01

    Full Text Available A comparison between the axon terminals of octopaminergic efferent dorsal or ventral unpaired median neurons in either desert locusts (Schistocerca gregaria or fruit flies (Drosophila melanogaster across skeletal muscles reveals many similarities. In both species the octopaminergic axon forms beaded fibers where the boutons or varicosities form type II terminals in contrast to the neuromuscular junction (NMJ or type I terminals. These type II terminals are immunopositive for both tyramine and octopamine and, in contrast to the type I terminals, which possess clear synaptic vesicles, only contain dense core vesicles. These dense core vesicles contain octopamine as shown by immunogold methods. With respect to the cytomatrix and active zone peptides the type II terminals exhibit active zone-like accumulations of the scaffold protein Bruchpilot (BRP only sparsely in contrast to the many accumulations of BRP identifying active zones of NMJ type I terminals. In the fruit fly larva marked dynamic changes of octopaminergic fibers have been reported after short starvation which not only affects the formation of new branches (“synaptopods” but also affects the type I terminals or NMJs via octopamine-signaling (Koon et al., 2011. Our starvation experiments of Drosophila-larvae revealed a time-dependency of the formation of additional branches. Whereas after 2 h of starvation we find a decrease in “synaptopods”, the increase is significant after 6 h of starvation. In addition, we provide evidence that the release of octopamine from dendritic and/or axonal type II terminals uses a similar synaptic machinery to glutamate release from type I terminals of excitatory motor neurons. Indeed, blocking this canonical synaptic release machinery via RNAi induced downregulation of BRP in neurons with type II terminals leads to flight performance deficits similar to those observed for octopamine mutants or flies lacking this class of neurons (Brembs et al., 2007.

  18. Amplification of marine methanotrophic enrichment DNA with 16S rDNA PCR primers for type II alpha proteobacteria methanotrophs.

    Science.gov (United States)

    Rockne, Karl J; Strand, Stuart E

    2003-09-01

    Type II alpha proteobacteria methanotrophs are capable of a wide range of cometabolic transformations of chlorinated solvents and polycyclic aromatic hydrocarbons (PAHs), and this activity has been exploited in many terrestrial bioremediation systems. However, at present, all known obligately marine methanotrophic isolates are Type I gamma proteobacteria which do not have this activity to the extent of Type II methanotrophs. In previous work in our laboratory, determining the presence of Type II alpha proteobacteria methanotrophs in marine enrichment cultures that co-metabolized PAHs required a more sensitive assay. 16S rDNA PCR primers were designed based on oligonucleotide probes for serine pathway methanotrophs and serine pathway methylotrophs with an approximate amplification fragment size of 870 base pairs. Comparison of the primers using double primer BLAST searches in established nucleotide databases showed potential amplification with all Methylocystis and Methylosinus spp., as well as potential amplification with Methylocella palustrus. DNA from Methylosinus trichosporium OB3b, a Type II methanotroph, amplified with the primers with a fragment size of approximately 850 base pairs, whereas DNA extracted from Methylomonas methanica, a Type I methanotroph, did not. The primers were used to amplify DNA extracted from two marine methanotrophic enrichment cultures: a low nitrogen/low copper enrichment to select for Type II methanotrophs and a high nitrogen/high copper enrichment to select for Type I methanotrophs. Although DNA from both cultures amplified with the PCR primers, amplification was stronger in cultures that were specifically enriched for Type II methanotrophs, suggesting the presence of higher numbers of Type II methanotrophs. These results provide further evidence for the existence of Type II marine methanotrophs, suggesting the possibility of exploiting cometabolic activity in marine systems.

  19. Heterotic/Type-II duality and its field theory avatars

    International Nuclear Information System (INIS)

    Kiritsis, Elias

    1999-01-01

    In these lecture notes, I will describe heterotic/type-II duality in six and four dimensions. When supersymmetry is the maximal N=4 it will be shown that the duality reduces in the field theory limit to the Montonen-Olive duality of N=4 Super Yang-Mills theory. We will consider further compactifications of type II theory on Calabi-Yau manifolds. We will understand the physical meaning of geometric conifold singularities and the dynamics of conifold transitions. When the CY manifold is a K3 fibration we will argue that the type-II ground-state is dual to the heterotic theory compactified on K3xT 2 . This allows an exact computation of the low effective action. Taking the field theory limit, α ' →0, we will recover the Seiberg-Witten non-perturbative solution of N=2 gauge theory

  20. Evolution of the central black hole in an active galactic nucleus. I. Evolution with a constant mass influx

    International Nuclear Information System (INIS)

    Park, S.J.; Vishniac, E.T.

    1988-01-01

    The long-term evolution of the central black hole in an active galactic nucleus (AGN), whose rotational energy is being extracted by the Blandford-Znajek process, was analyzed. The model is based on previous axisymmetric, stationary descriptions of the black hole and its magnetosphere, but includes the secular effects of the mass accretion rate. The properties of the black hole and the nonthermal radiation from its environment are calculated under the assumption that the mass influx is constant. It is noted that this model fails to explain the correlation of evolutionary time scale with luminosity or the extremely rapid evolution required for the most luminous sources. It is concluded that the evolution of AGNs is driven by a rapid decrease in mass accretion rate. Since the nature of an AGN is dependent on the ratio mass accretion/total mass, this leads to a conclusion that AGNs evolve from QSOs into the nuclei of Seyfert or radio galaxies. 20 references

  1. RELIABLE IDENTIFICATIONS OF ACTIVE GALACTIC NUCLEI FROM THE WISE, 2MASS, AND ROSAT ALL-SKY SURVEYS

    International Nuclear Information System (INIS)

    Edelson, R.; Malkan, M.

    2012-01-01

    We have developed the ''S IX '' statistic to identify bright, highly likely active galactic nucleus (AGN) candidates solely on the basis of Wide-field Infrared Survey Explorer (WISE), Two Micron All-Sky Survey (2MASS), and ROSAT all-sky survey (RASS) data. This statistic was optimized with data from the preliminary WISE survey and the Sloan Digital Sky Survey, and tested with Lick 3 m Kast spectroscopy. We find that sources with S IX 95% likelihood of being an AGN (defined in this paper as a Seyfert 1, quasar, or blazar). This statistic was then applied to the full WISE/2MASS/RASS dataset, including the final WISE data release, to yield the ''W2R'' sample of 4316 sources with S IX 2 , permitting construction of AGN samples in any sufficiently large region of sky.

  2. On the cosmic ray spectrum from type II Supernovae expanding in their red giant presupernova wind

    Science.gov (United States)

    Cardillo, Martina

    2015-12-01

    While from the energetic point of view SNRs are viable sources of Galactic CRs, the issue of whether they can accelerate protons up to PeV remains unsolved. Here we discuss particle acceleration at the forward shock of SN and discuss the possibility that the escaping particle current may excite a non-resonant instability that in turn leads to the formation of resonant modes confining particles close to the shock and increasing the maximum energy. This mechanism works throughout the expansion of the SN explosion, from the ejecta dominated (ED) to the Sedov-Taylor (ST) phase. Because of their higher explosion rate,we focus on type II SNae expanding in the slow, dense red supergiant wind. When the explosion occurs in such winds, the transition between the ED and the ST phase is likely to take place within a few tens of years. As a result, the spectrum of accelerated particles shows a break in the slope, at the maximum energy (EM) achieved at the beginning of the ST phase. Above this energy, the spectrum becomes steeper but remains a power law than developing an exponential cutoff. We show that for type II SNae typical parameters, proton EM can easily reach PeV energies, confirming that type II SNRs are the best candidate sources for CRs at the knee. We have tried to fit KASCADE-Grande, ARGO -YBJ and YAC1-Tibet Array data with our model but we could not find any parameter combination that could explain all data sets. Indeed the recent measurement of the proton and helium spectra in the knee region, with the ARGO-YBJ and YAC1-Tibet Array, has made the situation very confused. These measurements suggest that the knee in the light component is at 650 TeV, appreciably below the overall spectrum knee. This finding would resolve the problem of reaching very high energies in SNae, but, on the other hand, it would open a critical issue in the transition region between Galactic and extragalactic CRs.

  3. [Sulfatide-loaded CD1d tetramer to detect typeII NKT cells in mice].

    Science.gov (United States)

    Zhang, Gu-qin; Nie, Han-xiang; Yang, Jiong; Yu, Hong-ying

    2012-07-01

    To create a method of detecting typeII natural killer T (NKT) cells of mice. Biotinylated mouse CD1d monomers were mixed with sulfatide at a molar ratio of 1:3 (protein:lipid) and incubated at room temperature overnight, and then 80 μg of streptavidin-PE was added into 200 μg of the CD1d-sulfatide mixture and incubated at room temperature for 4 h to get sulfatide/CD1d tetramer. Flow cytometry was used to detect the percentage of typeII NKT cells in mononuclear cells (MNCs) of lung and spleen of normal mice, as well as the percentage of typeII NKT cells in spleen MNCs of mice after stimulated with sulfatide. In normal mice, the percentage of typeII NKT cells accounted for (0.875±0.096)% and (1.175±0.263)% in MNCs of spleen and lung; the percentage in spleen MNCs after activated with sulfatide was (2.75±0.603)%, which significantly increased as compared with that in normal mice (PNKT cells in mice.

  4. Nonrandom association of a type II procollagen genotype with achondroplasia

    OpenAIRE

    1986-01-01

    Achondroplasia is an autosomal dominant disorder that involves defective endochondral bone formation. Type II collagen is the predominant collagen of cartilage. We found a HindIII polymorphic site in the normal Caucasian population by using the type II procollagen gene probe pgHCol(II)A. The presence of this site yields a 7.0-kilobase (kb) band; its absence yields a 14.0-kb band. We found a significant deviation in genotype distribution and allele frequencies in a population of unrelated indi...

  5. Autosomic dominant type II Osteopetrosis (Albers-Schonberg disease)

    International Nuclear Information System (INIS)

    Zambrano, Angela R; Salamanca, Juan C; Ospino, Benjamin

    2003-01-01

    The osteopetrosis type II or albers-schonberg disease is an infrequent disease secondary to the decrease in the bone resorption. The osteoclast is the principal cell involved in the disease. The osteopetrosis is characterized by few symptoms and it also has a benign course, but may further develop medullar insufficiency. We report a case of a young patient that initially shows, thrombocytopenia and bone pain with increase in the bone density, suggestive of osteopetrosis type II. The x ray exam was conclusive of osteopetrosis

  6. Stability conditions for the Bianchi type II anisotropically inflating universes

    International Nuclear Information System (INIS)

    Kao, W.F.; Lin, Ing-Chen

    2009-01-01

    Stability conditions for a class of anisotropically inflating solutions in the Bianchi type II background space are shown explicitly in this paper. These inflating solutions were known to break the cosmic no-hair theorem such that they do not approach the de Sitter universe at large times. It can be shown that unstable modes of the anisotropic perturbations always exist for this class of expanding solutions. As a result, we show that these set of anisotropically expanding solutions are unstable against anisotropic perturbations in the Bianchi type II space

  7. THE X-RAY POWER SPECTRAL DENSITY FUNCTION OF THE SEYFERT ACTIVE GALACTIC NUCLEUS NGC 7469

    International Nuclear Information System (INIS)

    Markowitz, A.

    2010-01-01

    We present the broadband X-ray power spectral density (PSD) function of the X-ray-luminous Seyfert 1.2 NGC 7469, measured from Rossi X-ray Timing Explorer monitoring data and two XMM-Newton observations. We find significant evidence for a turnover in the 2-10 keV PSD at a temporal frequency of 2.0 +3.0 -0.8 x 10 -6 Hz or 1.0 +3.0 -0.6 x 10 -6 Hz, depending on the exact form of the break (sharply broken or slowly bending power law, respectively). The 'surrogate' Monte Carlo method of Press et al. was used to map out the probability distributions of PSD model parameters and obtain reliable uncertainties (68% confidence limits quoted here). The corresponding break timescale of 5.8 ± 3.5 days or 11.6 +17.5 -8.7 days, respectively, is consistent with the empirical relation between PSD break timescale, black hole mass, and bolometric luminosity of McHardy et al. Compared to the 2-10 keV PSD, the 10-20 keV PSD has a much flatter shape at high temporal frequencies, and no PSD break is significantly detected, suggesting an energy-dependent evolution not unlike that exhibited by several Galactic black hole systems.

  8. The Structure and Dynamics of An Active Galactic Nucleus Torus : CO Line Predictions for ALMA from Three-dimensional Hydrodynamical Simulations with X-ray-driven Chemistry

    NARCIS (Netherlands)

    Perez Beaupuits, J.P.; Wada, K.; Spaans, M.

    2011-01-01

    Several attempts have been made to model the mass distribution and dynamical evolution of the circumnuclear gas in active galactic nuclei (AGNs). However, chemical evolution is not included in detail in three-dimensional (3D) hydrodynamic simulations. The X-ray radiation from the AGN can drive the

  9. NuSTAR Observations of the Compton-Thick Active Galactic Nucleus and Ultraluminous X-Ray Source Candidate in NGC 5643

    DEFF Research Database (Denmark)

    Annuar, A.; Gandhi, P.; Alexander, D. M.

    2015-01-01

    We present two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the local Seyfert 2 active galactic nucleus (AGN) and an ultraluminous X-ray source (ULX) candidate in NGC 5643. Together with archival data from Chandra, XMM-Newton, and Swift-BAT, we perform a high-quality broadband s...

  10. Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database

    DEFF Research Database (Denmark)

    Peterson, B. M.; Ferrarese, L.; Gilbert, K. M.

    2004-01-01

    We present improved black hole masses for 35 active galactic nuclei (AGNs) based on a complete and consistent reanalysis of broad emission-line reverberation-mapping data. From objects with multiple line measurements, we find that the highest precision measure of the virial product is obtained...

  11. The Radius-Luminosity Relationship for Active Galactic Nuclei: The Effect of Host-Galaxy Starlight on Luminosity Measurements. II. The Full Sample of Reverberation-Mapped AGNs

    DEFF Research Database (Denmark)

    Bentz, Misty C.; Peterson, Bradley M.; Netzer, Hagai

    2009-01-01

    We present high-resolution Hubble Space Telescope images of all 35 active galactic nuclei (AGNs) with optical reverberation-mapping results, which we have modeled to create a nucleus-free image of each AGN host galaxy. From the nucleus-free images, we determine the host-galaxy contribution to gro...

  12. THE LONGEST TIMESCALE X-RAY VARIABILITY REVEALS EVIDENCE FOR ACTIVE GALACTIC NUCLEI IN THE HIGH ACCRETION STATE

    International Nuclear Information System (INIS)

    Zhang Youhong

    2011-01-01

    The All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer has continuously monitored a number of active galactic nuclei (AGNs) with similar sampling rates for 14 years, from 1996 January to 2009 December. Utilizing the archival ASM data of 27 AGNs, we calculate the normalized excess variances of the 300-day binned X-ray light curves on the longest timescale (between 300 days and 14 years) explored so far. The observed variance appears to be independent of AGN black-hole mass and bolometric luminosity. According to the scaling relation of black-hole mass (and bolometric luminosity) from galactic black hole X-ray binaries (GBHs) to AGNs, the break timescales that correspond to the break frequencies detected in the power spectral density (PSD) of our AGNs are larger than the binsize (300 days) of the ASM light curves. As a result, the singly broken power-law (soft-state) PSD predicts the variance to be independent of mass and luminosity. Nevertheless, the doubly broken power-law (hard-state) PSD predicts, with the widely accepted ratio of the two break frequencies, that the variance increases with increasing mass and decreases with increasing luminosity. Therefore, the independence of the observed variance on mass and luminosity suggests that AGNs should have soft-state PSDs. Taking into account the scaling of the break timescale with mass and luminosity synchronously, the observed variances are also more consistent with the soft-state than the hard-state PSD predictions. With the averaged variance of AGNs and the soft-state PSD assumption, we obtain a universal PSD amplitude of 0.030 ± 0.022. By analogy with the GBH PSDs in the high/soft state, the longest timescale variability supports the standpoint that AGNs are scaled-up GBHs in the high accretion state, as already implied by the direct PSD analysis.

  13. RELIABLE IDENTIFICATIONS OF ACTIVE GALACTIC NUCLEI FROM THE WISE, 2MASS, AND ROSAT ALL-SKY SURVEYS

    Energy Technology Data Exchange (ETDEWEB)

    Edelson, R. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Malkan, M., E-mail: rickedelson@gmail.com [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095-1547 (United States)

    2012-05-20

    We have developed the ''S{sub IX}'' statistic to identify bright, highly likely active galactic nucleus (AGN) candidates solely on the basis of Wide-field Infrared Survey Explorer (WISE), Two Micron All-Sky Survey (2MASS), and ROSAT all-sky survey (RASS) data. This statistic was optimized with data from the preliminary WISE survey and the Sloan Digital Sky Survey, and tested with Lick 3 m Kast spectroscopy. We find that sources with S{sub IX} < 0 have a {approx}>95% likelihood of being an AGN (defined in this paper as a Seyfert 1, quasar, or blazar). This statistic was then applied to the full WISE/2MASS/RASS dataset, including the final WISE data release, to yield the ''W2R'' sample of 4316 sources with S{sub IX} < 0. Only 2209 of these sources are currently in the Veron-Cetty and Veron (VCV) catalog of spectroscopically confirmed AGNs, indicating that the W2R sample contains nearly 2000 new, relatively bright (J {approx}< 16) AGNs. We utilize the W2R sample to quantify biases and incompleteness in the VCV catalog. We find that it is highly complete for bright (J < 14), northern AGNs, but the completeness drops below 50% for fainter, southern samples and for sources near the Galactic plane. This approach also led to the spectroscopic identification of 10 new AGNs in the Kepler field, more than doubling the number of AGNs being monitored by Kepler. The W2R sample contains better than 1 bright AGN every 10 deg{sup 2}, permitting construction of AGN samples in any sufficiently large region of sky.

  14. A NEW PERSPECTIVE OF THE RADIO BRIGHT ZONE AT THE GALACTIC CENTER: FEEDBACK FROM NUCLEAR ACTIVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Morris, Mark R. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Goss, W. M., E-mail: jzhao@cfa.harvard.edu [NRAO, P.O. Box O, Socorro, NM 87801 (United States)

    2016-02-01

    New observations of Sgr A have been carried out with the Jansky VLA in the B and C arrays using the broadband (2 GHz) continuum mode at 5.5 GHz. The field of view covers the central 13′ (30 pc) region of the radio-bright zone at the Galactic center. Using the multi-scale and multi-frequency-synthesis (MS-MFS) algorithms in CASA, we have imaged Sgr A with a resolution of 1″, achieving an rms noise of 8 μJy beam{sup −1}, and a dynamic range of 100,000:1. Both previously known and newly identified radio features in this region are revealed, including numerous filamentary sources. The radio continuum image is compared with Chandra X-ray images, with a CN emission-line image obtained with the Submillimeter Array and with detailed Paschen-α images obtained with Hubble Space Telescope/NICMOS. We discuss several prominent features in the radio image. The “Sgr A west Wings” extend 2′ (5 pc) from the NW and SE tips of the Sgr A west H ii region (the “Mini-spiral”) to positions located 2.9 and 2.4 arcmin to the northwest and southeast of Sgr A*, respectively. The NW wing, along with several other prominent features, including the previously identified “NW Streamers,” form an elongated radio lobe (NW lobe), oriented nearly perpendicular to the Galactic plane. This radio lobe, with a size of 6.′3 × 3.′2 (14.4 pc × 7.3 pc), has a known X-ray counterpart. In the outer region of the NW lobe, a row of three thermally emitting rings is observed. A field containing numerous amorphous radio blobs extends for a distance of ∼2 arcmin beyond the tip of the SE wing; these newly recognized features coincide with the SE X-ray lobe. Most of the amorphous radio blobs in the NW and SE lobes have Paschen-α counterparts. We propose that they have been produced by shock interaction of ambient gas concentrations with a collimated nuclear wind or an outflow that originated from within the circumnuclear disk (CND). We also discuss the possibility that the ionized

  15. Star Formation Activity in the Galactic H II Region Sh2-297

    Science.gov (United States)

    Mallick, K. K.; Ojha, D. K.; Samal, M. R.; Pandey, A. K.; Bhatt, B. C.; Ghosh, S. K.; Dewangan, L. K.; Tamura, M.

    2012-11-01

    We present a multiwavelength study of the Galactic H II region Sh2-297, located in the Canis Major OB1 complex. Optical spectroscopic observations are used to constrain the spectral type of ionizing star HD 53623 as B0V. The classical nature of this H II region is affirmed by the low values of electron density and emission measure, which are calculated to be 756 cm-3 and 9.15 × 105 cm-6 pc using the radio continuum observations at 610 and 1280 MHz, and Very Large Array archival data at 1420 MHz. To understand local star formation, we identified the young stellar object (YSO) candidates in a region of area ~7farcm5 × 7farcm5 centered on Sh2-297 using grism slitless spectroscopy (to identify the Hα emission line stars), and near infrared (NIR) observations. NIR YSO candidates are further classified into various evolutionary stages using color-color and color-magnitude (CM) diagrams, giving 50 red sources (H - K > 0.6) and 26 Class II-like sources. The mass and age range of the YSOs are estimated to be ~0.1-2 M ⊙ and 0.5-2 Myr using optical (V/V-I) and NIR (J/J-H) CM diagrams. The mean age of the YSOs is found to be ~1 Myr, which is of the order of dynamical age of 1.07 Myr of the H II region. Using the estimated range of visual extinction (1.1-25 mag) from literature and NIR data for the region, spectral energy distribution models have been implemented for selected YSOs which show masses and ages to be consistent with estimated values. The spatial distribution of YSOs shows an evolutionary sequence, suggesting triggered star formation in the region. The star formation seems to have propagated from the ionizing star toward the cold dark cloud LDN1657A located west of Sh2-297.

  16. Dynamo dominated accretion and energy flow: The mechanism of active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Colgate, S.A.; Li, H.

    1998-12-31

    An explanation of the magnetic fields of the universe, the central mass concentration of galaxies, the massive black hole of every galaxy, and the AGN phenomena has been an elusive goal. The authors suggest here the outlines of such a theoretical understanding and point out where the physical understanding is missing. They believe there is an imperative to the sequence of mass flow and hence energy flow in the collapse of a galactic mass starting from the first non-linearity appearing in structure formation following decoupling. This first non-linearity of a two to one density fluctuation, the Lyman-{alpha} clouds, ultimately leads to the emission spectra of the phenomenon of AGN, quasars, blazars, etc. The over-arching physical principle is the various mechanisms for the transport of angular momentum. They believe they have now understood the new physics of two of these mechanisms that have previously been illusive and as a consequence they impose strong constraints on the initial conditions of the mechanisms for the subsequent emission of the gravitational binding energy. The new phenomena described are: (1) the Rossby vortex mechanism of the accretion disk {alpha}-viscosity, and (2) the mechanism of the {alpha}-{Omega} dynamo in the accretion disk. The Rossby vortex mechanism leads to a prediction of the black hole mass and rate of energy release and the {alpha}-{Omega} dynamo leads to the generation of the magnetic flux of the galaxy (and the far greater magnetic flux of clusters) and separately explains the primary flux of energy emission as force-free magnetic energy density. This magnetic flux and magnetic energy density separately are the necessary consequence of the saturation of a dynamo created by the accretion disk with a gain greater than unity.

  17. 33 CFR 159.126 - Coliform test: Type II devices.

    Science.gov (United States)

    2010-07-01

    ... follows: During each of the 10 test days, one sample must be taken at the beginning, middle and end of an 8-consecutive hour period with one additional sample taken immediately following the peak capacity...: Type II devices. (a) The arithmetic mean of the fecal coliform bacteria in 38 of 40 samples of effluent...

  18. Evidence for topological type-II Weyl semimetal WTe2

    KAUST Repository

    Li, Peng

    2017-12-11

    Recently, a type-II Weyl fermion was theoretically predicted to appear at the contact of electron and hole Fermi surface pockets. A distinguishing feature of the surfaces of type-II Weyl semimetals is the existence of topological surface states, so-called Fermi arcs. Although WTe2 was the first material suggested as a type-II Weyl semimetal, the direct observation of its tilting Weyl cone and Fermi arc has not yet been successful. Here, we show strong evidence that WTe2 is a type-II Weyl semimetal by observing two unique transport properties simultaneously in one WTe2 nanoribbon. The negative magnetoresistance induced by a chiral anomaly is quite anisotropic in WTe2 nanoribbons, which is present in b-axis ribbon, but is absent in a-axis ribbon. An extra-quantum oscillation, arising from a Weyl orbit formed by the Fermi arc and bulk Landau levels, displays a two dimensional feature and decays as the thickness increases in WTe2 nanoribbon.

  19. Acute type II cryoglobulinaemic vasculitis mimicking atherosclerotic peripheral vascular disease.

    LENUS (Irish Health Repository)

    Saeed, A

    2012-01-31

    Atherosclerotic peripheral vascular disease is a common presenting cause for digital ischaemia in life long smokers. Acute severe Type II Cryoglobulinaemic vasculitis is a rare yet important cause, which may present with similar clinical features and which if undiagnosed may be rapidly fatal. Following the instigation of therapy with intravenous methylprednisolone and cyclophosphamide this patient made an excellent recovery.

  20. Hypertension In Type II Diabetes Mellitus In Jos University Teaching ...

    African Journals Online (AJOL)

    Methods: A cross-sectional study of hypertension in type II diabetic patients in Jos University Teaching Hospital, Jos, Nigeria Results: Forty-two of the patients were hypertensive with only 28 (32.9%) previously diagnosed and were on treatment. Age of patient, duration of diabetes and diabetic retinopathy were significantly ...

  1. Ambitwistor pure spinor string in a type II supergravity background

    Energy Technology Data Exchange (ETDEWEB)

    Chandia, Osvaldo [Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez,Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Diagonal Las Torres 2640, Peñalolén, Santiago (Chile); Vallilo, Brenno Carlini [Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andres Bello,República 220, Santiago (Chile)

    2015-06-30

    We construct the ambitwistor pure spinor string in a general type II supergravity background in the semi-classical regime. Almost all supergravity constraints are obtained from nilpotency of the BRST charge and further consistency conditions from additional world-sheet the case of AdS{sub 5}×S{sup 5} background.

  2. Towards Optimal Diagnosis of Type II Germ Cell Tumors

    NARCIS (Netherlands)

    J.A. Stoop (Hans)

    2011-01-01

    textabstractThe aim of the work described in this thesis is to improve the understanding of the pathobiology of testicular cancer (type II Germ Cell Tumors) to create possibilities for optimalization of diagnosis for this type of malignancy in routine pathology laboratories. The different studies

  3. Type II restriction endonucleases--a historical perspective and more.

    Science.gov (United States)

    Pingoud, Alfred; Wilson, Geoffrey G; Wende, Wolfgang

    2014-07-01

    This article continues the series of Surveys and Summaries on restriction endonucleases (REases) begun this year in Nucleic Acids Research. Here we discuss 'Type II' REases, the kind used for DNA analysis and cloning. We focus on their biochemistry: what they are, what they do, and how they do it. Type II REases are produced by prokaryotes to combat bacteriophages. With extreme accuracy, each recognizes a particular sequence in double-stranded DNA and cleaves at a fixed position within or nearby. The discoveries of these enzymes in the 1970s, and of the uses to which they could be put, have since impacted every corner of the life sciences. They became the enabling tools of molecular biology, genetics and biotechnology, and made analysis at the most fundamental levels routine. Hundreds of different REases have been discovered and are available commercially. Their genes have been cloned, sequenced and overexpressed. Most have been characterized to some extent, but few have been studied in depth. Here, we describe the original discoveries in this field, and the properties of the first Type II REases investigated. We discuss the mechanisms of sequence recognition and catalysis, and the varied oligomeric modes in which Type II REases act. We describe the surprising heterogeneity revealed by comparisons of their sequences and structures. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  4. Left Ventricular Geometry In Nigerians With Type II Diabetes Mellitus ...

    African Journals Online (AJOL)

    Background: Left ventricular hypertrophy is independently associated with increased incidence of cardiovascular disease, cardiovascular and all cause mortality. In a relatively healthy hypertensive adult population, type II diabetes is associated with higher left ventricular mass, concentric left ventricular geometry and lower ...

  5. Localization of Usher syndrome type II to chromosome 1q.

    Science.gov (United States)

    Kimberling, W J; Weston, M D; Möller, C; Davenport, S L; Shugart, Y Y; Priluck, I A; Martini, A; Milani, M; Smith, R J

    1990-06-01

    Usher syndrome is characterized by congenital hearing loss, progressive visual impairment due to retinitis pigmentosa, and variable vestibular problems. The two subtypes of Usher syndrome, types I and II, can be distinguished by the degree of hearing loss and by the presence or absence of vestibular dysfunction. Type I is characterized by a profound hearing loss and totally absent vestibular responses, while type II has a milder hearing loss and normal vestibular function. Fifty-five members of eight type II Usher syndrome families were typed for three DNA markers in the distal region of chromosome 1q: D1S65 (pEKH7.4), REN (pHRnES1.9), and D1S81 (pTHH33). Statistically significant linkage was observed for Usher syndrome type II with a maximum multipoint lod score of 6.37 at the position of the marker THH33, thus localizing the Usher type II (USH2) gene to 1q. Nine families with type I Usher syndrome failed to show linkage to the same three markers. The statistical test for heterogeneity of linkage between Usher syndrome types I and II was highly significant, thus demonstrating that they are due to mutations at different genetic loci.

  6. Aspartame: should individuals with Type II Diabetes be taking it?

    Science.gov (United States)

    Choudhary, Arbind Kumar

    2017-05-31

    Individuals with type II diabetes (T2D) have to manage blood glucose levels to sustain health and longevity. Artificial sweeteners (including aspartame) are suggested sugar alternatives for these individuals. The safety of aspartame in particular, has long been the centre of debate. Although it is such a controversial product, many clinicians recommend its use to T2D patients, during a controlled diet and as part of an intervention strategy. Aspartame is 200 times sweeter than sugar and has a negligible effect on blood glucose levels, and it is suggested for use so that T2D can control carbohydrate intake and blood glucose levels. However, research suggests that aspartame intake may lead to an increased risk of weight gain rather than weight loss, and cause impaired blood glucose tolerance in T2D. This review consolidates knowledge gained from studies that link aspartame consumption to the various mechanisms associated with T2D. We review literature that provides evidence that raise concerns that aspartame may exacerbate T2D and add to the global burden of disease. Aspartame may act as a chemical stressor by increasing cortisol levels, and may induce systemic oxidative stress by producing excess free radicals, and it may also alter gut microbial activity and interfere with the N-methyl D-aspartate (NMDA) receptor, resulting in insulin deficiency or resistance. Aspartame and its metabolites are safe for T2D is still debatable due to a lack of consistent data. More research is required that provides evidence and raise concerns that aspartame may exacerbate prevalence of pathological physiology in the already stressed physiology of T2D. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. Behavioral effects of type II pyrethroid cyhalothrin in rats

    International Nuclear Information System (INIS)

    Righi, D. Abbud; Palermo-Neto, J.

    2003-01-01

    Synthetic pyrethroids such as cyhalothrin are extensively used in agriculture for the control of a broad range of ectoparasites in farm animals. It has been suggested that type II pyrethroids might induce anxiogenic-like effects in laboratory animals. The present study was undertaken to investigate a possible anxiogenic-like outcome of cyhalothrin in rats. Adult male rats were orally dosed for 7 days with 1.0, 3.0, or 7.0 mg/kg/day of cyhalothrin, present in a commercial formulation (Grenade Coopers do Brazil S.A.). The neurobehavioral changes induced by cyhalothrin as well as those produced on corticosterone serum levels were measured 24 h after the last treatment. Picrotoxin (1.0 mg/kg) was also acutely used as a positive control for anxiety. Results showed that cyhalothrin: (1) induced some signs and symptoms of intoxication that included salivation, tremors, and liquid feces; (2) reduced total locomotor activity in the open-field; (3) reduced the percentage of time spent in open-field central zones; (4) increased immobility time in the open-field; (5) reduced the percentage of time spent in plus-maze open arms exploration; (6) reduced the time spent in social interactions, and (7) increased the levels of serum corticosterone. The behavioral changes reported for cyhalothrin (3.0 mg/kg/day) were similar of those induced by picrotoxin. The no effect level dose obtained for cyhalothrin in this study was 1.0 mg/kg/day. These results provide experimental evidence that cyhalothrin induces anxiety-like symptoms, with this effect being dose-related. Thus, anxiety must be included among the several signs and symptoms of pesticide intoxication

  8. Coordinate expression of activating Fc gamma receptors I and III and inhibiting Fc gamma receptor type II in the determination of joint inflammation and cartilage destruction during immune complex-mediated arthritis.

    NARCIS (Netherlands)

    Nabbe, K.C.A.M.; Blom, A.B.; Holthuysen, A.E.M.; Boross, P.; Roth, J.; Verbeek, S.; Lent, P.L.E.M. van; Berg, W.B. van den

    2003-01-01

    OBJECTIVE: To study the role of the activating Fc gamma receptor types I and III (Fc gamma RI and Fc gamma RIII, respectively) and the inhibiting Fc gamma receptor II (Fc gamma RII) in inflammation and in various aspects of cartilage destruction during arthritis that is solely induced by immune

  9. Effects of type II thyroplasty on adductor spasmodic dysphonia.

    Science.gov (United States)

    Sanuki, Tetsuji; Yumoto, Eiji; Minoda, Ryosei; Kodama, Narihiro

    2010-04-01

    Type II thyroplasty, or laryngeal framework surgery, is based on the hypothesis that the effect of adductor spasmodic dysphonia (AdSD) on the voice is due to excessively tight closure of the glottis, hampering phonation. Most of the previous, partially effective treatments have aimed to relieve this tight closure, including recurrent laryngeal nerve section or avulsion, extirpation of the adductor muscle, and botulinum toxin injection, which is currently the most popular. The aim of this study was to assess the effects of type II thyroplasty on aerodynamic and acoustic findings in patients with AdSD. Case series. University hospital. Ten patients with AdSD underwent type II thyroplasty between August 2006 and December 2008. Aerodynamic and acoustic analyses were performed prior to and six months after surgery. Mean flow rates (MFRs) and voice efficiency were evaluated with a phonation analyzer. Jitter, shimmer, the harmonics-to-noise ratio (HNR), standard deviation of the fundamental frequency (SDF0), and degree of voice breaks (DVB) were measured from each subject's longest sustained phonation sample of the vowel /a/. Voice efficiency improved significantly after surgery. No significant difference was found in the MFRs between before and after surgery. Jitter, shimmer, HNR, SDF0, and DVB improved significantly after surgery. Treatment of AdSD with type II thyroplasty significantly improved aerodynamic and acoustic findings. The results of this study suggest that type II thyroplasty provides relief from voice strangulation in patients with AdSD. Copyright 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.

  10. STAR FORMATION ACTIVITY IN THE GALACTIC H II REGION Sh2-297

    International Nuclear Information System (INIS)

    Mallick, K. K.; Ojha, D. K.; Dewangan, L. K.; Samal, M. R.; Pandey, A. K.; Bhatt, B. C.; Ghosh, S. K.; Tamura, M.

    2012-01-01

    We present a multiwavelength study of the Galactic H II region Sh2-297, located in the Canis Major OB1 complex. Optical spectroscopic observations are used to constrain the spectral type of ionizing star HD 53623 as B0V. The classical nature of this H II region is affirmed by the low values of electron density and emission measure, which are calculated to be 756 cm –3 and 9.15 × 10 5 cm –6 pc using the radio continuum observations at 610 and 1280 MHz, and Very Large Array archival data at 1420 MHz. To understand local star formation, we identified the young stellar object (YSO) candidates in a region of area ∼7.'5 × 7.'5 centered on Sh2-297 using grism slitless spectroscopy (to identify the Hα emission line stars), and near infrared (NIR) observations. NIR YSO candidates are further classified into various evolutionary stages using color-color and color-magnitude (CM) diagrams, giving 50 red sources (H – K > 0.6) and 26 Class II-like sources. The mass and age range of the YSOs are estimated to be ∼0.1-2 M ☉ and 0.5-2 Myr using optical (V/V–I) and NIR (J/J–H) CM diagrams. The mean age of the YSOs is found to be ∼1 Myr, which is of the order of dynamical age of 1.07 Myr of the H II region. Using the estimated range of visual extinction (1.1-25 mag) from literature and NIR data for the region, spectral energy distribution models have been implemented for selected YSOs which show masses and ages to be consistent with estimated values. The spatial distribution of YSOs shows an evolutionary sequence, suggesting triggered star formation in the region. The star formation seems to have propagated from the ionizing star toward the cold dark cloud LDN1657A located west of Sh2-297.

  11. THE LOW FREQUENCY OF DUAL ACTIVE GALACTIC NUCLEI VERSUS THE HIGH MERGER RATE OF GALAXIES: A PHENOMENOLOGICAL MODEL

    International Nuclear Information System (INIS)

    Yu Qingjuan; Lu Youjun; Mohayaee, Roya; Colin, Jacques

    2011-01-01

    Dual active galactic nuclei (AGNs) are natural byproducts of hierarchical mergers of galaxies in the ΛCDM cosmogony. Recent observations have shown that only a small fraction (∼0.1%-2.5%) of AGNs at redshift z ∼< 0.3 are dual with kpc-scale separations, which is rather low compared to the high merger rate of galaxies. Here we construct a phenomenological model to estimate the number density of dual AGNs and its evolution according to the observationally estimated major merger rates of galaxies and various scaling relations on the properties of galaxies and their central massive black holes. We show that our model reproduces the observed frequency and separation distribution of dual AGNs provided that significant nuclear activities are triggered only in gas-rich progenitor galaxies with central massive black holes and only when the nuclei of these galaxies are roughly within the half-light radii of their companion galaxies. Under these constraints, the observed low dual AGN frequency is consistent with the relatively high merger rate of galaxies and supports the hypothesis that major mergers lead to AGN/QSO activities. We also predict that the number of kpc-scale dual AGNs decreases with increasing redshift and only about 0.02%-0.06% of AGNs are dual AGNs with double-peaked narrow line features at redshifts of z ∼ 0.5-1.2. Future observations of high-redshift dual AGNs would provide a solid test for this prediction.

  12. Flux expulsion and trapping in rotating discs of type II superconductors

    International Nuclear Information System (INIS)

    Boyer, R.; Leblanc, M.A.R.

    1977-01-01

    The magnetic flux rotating in step with a type II superconducting disc is measured with orthogonal pick up coils for various previous magnetic histories vs H 0 applied at right angles to the axis of rotation. For some initial magnetic states, flux expulsion, independent of the rate of rotation, occurs during the initial rotation. A simple model where flux lines leave the specimen against the magnetic pressure in the active region accounts for the observations. (author)

  13. Luminescence dynamics in type-II GaAs/AlAs superlattices near the type-I to type-II crossover

    DEFF Research Database (Denmark)

    Langbein, Wolfgang Werner; Kalt, H.; Hvam, Jørn Märcher

    1996-01-01

    We report on a study of the time-resolved luminescence of type-II GaAs/AlAs superlattices near the type-I to type-II crossover. In spite of the slight type-II band alignment, the luminescence is dominated by the type-I transition. This is due to the inhomogeneous broadening of the type-I transiti...

  14. cAMP response element binding protein1 is essential for activation of steroyl co-enzyme a desaturase 1 (Scd1 in mouse lung type II epithelial cells.

    Directory of Open Access Journals (Sweden)

    Nisha Antony

    Full Text Available Cyclic AMP Response Element-Binding Protein 1 (Creb1 is a transcription factor that mediates cyclic adenosine 3', 5'-monophosphate (cAMP signalling in many tissues. Creb1(-/- mice die at birth due to respiratory failure and previous genome-wide microarray analysis of E17.5 Creb1(-/- fetal mouse lung identified important Creb1-regulated gene targets during lung development. The lipogenic enzymes stearoyl-CoA desaturase 1 (Scd1 and fatty acid synthase (Fasn showed highly reduced gene expression in Creb1(-/- lungs. We therefore hypothesized that Creb1 plays a crucial role in the transcriptional regulation of genes involved in pulmonary lipid biosynthetic pathways during lung development. In this study we confirmed that Scd1 and Fasn mRNA levels were down regulated in the E17.5 Creb1(-/- mouse lung while the lipogenic-associated transcription factors SrebpF1, C/ebpα and Pparγ were increased. In vivo studies using germline (Creb1(-/- and lung epithelial-specific (Creb1(EpiΔ/Δ Creb1 knockout mice showed strongly reduced Scd1, but not Fasn gene expression and protein levels in lung epithelial cells. In vitro studies using mouse MLE-15 epithelial cells showed that forskolin-mediated activation of Creb1 increased both Scd1 gene expression and protein synthesis. Additionally, MLE15 cells transfected with a dominant-negative ACreb vector blocked forskolin-mediated stimulation of Scd1 gene expression. Lipid profiling in MLE15 cells showed that dominant-negative ACreb suppressed forskolin-induced desaturation of ether linked lipids to produce plasmalogens, as well as levels of phosphatidylethanolamine, ceramide and lysophosphatidylcholine. Taken together these results demonstrate that Creb1 is essential for the induction and maintenance of Scd1 in developing fetal mouse lung epithelial cells.

  15. LUMINOUS BURIED ACTIVE GALACTIC NUCLEI AS A FUNCTION OF GALAXY INFRARED LUMINOSITY REVEALED THROUGH SPITZER LOW-RESOLUTION INFRARED SPECTROSCOPY

    International Nuclear Information System (INIS)

    Imanishi, Masatoshi

    2009-01-01

    We present the results of Spitzer Infrared Spectrograph 5-35 μm low-resolution spectroscopic energy diagnostics of ultraluminous infrared galaxies (ULIRGs) at z> 0.15, classified optically as non-Seyferts. Based on the equivalent widths of polycyclic aromatic hydrocarbon emission and the optical depths of silicate dust absorption features, we searched for signatures of intrinsically luminous, but optically elusive, buried active galactic nuclei (AGNs) in these optically non-Seyfert ULIRGs. We then combined the results with those of non-Seyfert ULIRGs at z IR 12 L sun . We found that the energetic importance of buried AGNs clearly increases with galaxy infrared luminosity, becoming suddenly discernible in ULIRGs with L IR > 10 12 L sun . For ULIRGs with buried AGN signatures, a significant fraction of infrared luminosities can be accounted for by the detected buried AGN and modestly obscured (A V < 20 mag) starburst activity. The implied masses of spheroidal stellar components in galaxies for which buried AGNs become important roughly correspond to the value separating red massive and blue less-massive galaxies in the local universe. Our results may support the widely proposed AGN-feedback scenario as the origin of galaxy downsizing phenomena, where galaxies with currently larger stellar masses previously had higher AGN energetic contributions and star formation originating infrared luminosities, and have finished their major star formation more quickly, due to stronger AGN feedback.

  16. Active Galactic Nucleus Obscuration from Winds: From Dusty Infrared-Driven to Warm and X-Ray Photoionized

    Science.gov (United States)

    Dorodnitsyn, Anton V.; Kallman, Timothy R.

    2012-01-01

    We present calculations of active galactic nucleus winds at approx.parsec scales along with the associated obscuration. We take into account the pressure of infrared radiation on dust grains and the interaction of X-rays from a central black hole with hot and cold plasma. Infrared radiation (IR) is incorporated in radiation-hydrodynamic simulations adopting the flux-limited diffusion approximation. We find that in the range of X-ray luminosities L = 0.05-0.6 L(sub Edd), the Compton-thick part of the flow (aka torus) has an opening angle of approximately 72deg - 75deg regardless of the luminosity. At L > or approx. 0.1, the outflowing dusty wind provides the obscuration with IR pressure playing a major role. The global flow consists of two phases: the cold flow at inclinations (theta) > or approx.70deg and a hot, ionized wind of lower density at lower inclinations. The dynamical pressure of the hot wind is important in shaping the denser IR-supported flow. At luminosities < or = 0.1 L(sub Edd) episodes of outflow are followed by extended periods when the wind switches to slow accretion. Key words: acceleration of particles . galaxies: active . hydrodynamics . methods: numerical Online-only material: color figures

  17. Galaxy Evolution in the Radio Band: The Role of Star-forming Galaxies and Active Galactic Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Mancuso, C.; Prandoni, I. [INAF-IRA, Via P. Gobetti 101, I-40129 Bologna (Italy); Lapi, A.; Obi, I.; Perrotta, F.; Bressan, A.; Celotti, A.; Danese, L. [SISSA, Via Bonomea 265, I-34136 Trieste (Italy); Gonzalez-Nuevo, J. [Departamento de Fisica, Universidad de Oviedo, C. Calvo Sotelo s/n, E-33007 Oviedo (Spain)

    2017-06-20

    We investigate the astrophysics of radio-emitting star-forming galaxies and active galactic nuclei (AGNs) and elucidate their statistical properties in the radio band, including luminosity functions, redshift distributions, and number counts at sub-mJy flux levels, which will be crucially probed by next-generation radio continuum surveys. Specifically, we exploit the model-independent approach by Mancuso et al. to compute the star formation rate functions, the AGN duty cycles, and the conditional probability of a star-forming galaxy to host an AGN with given bolometric luminosity. Coupling these ingredients with the radio emission properties associated with star formation and nuclear activity, we compute relevant statistics at different radio frequencies and disentangle the relative contribution of star-forming galaxies and AGNs in different radio luminosity, radio flux, and redshift ranges. Finally, we highlight that radio-emitting star-forming galaxies and AGNs are expected to host supermassive black holes accreting with different Eddington ratio distributions and to occupy different loci in the galaxy main-sequence diagrams. These specific predictions are consistent with current data sets but need to be tested with larger statistics via future radio data with multiband coverage on wide areas, as will become routinely achievable with the advent of the Square Kilometre Array and its precursors.

  18. SDSS-IV MaNGA: identification of active galactic nuclei in optical integral field unit surveys

    Science.gov (United States)

    Wylezalek, Dominika; Zakamska, Nadia L.; Greene, Jenny E.; Riffel, Rogemar A.; Drory, Niv; Andrews, Brett H.; Merloni, Andrea; Thomas, Daniel

    2018-02-01

    In this paper, we investigate 2727 galaxies observed by MaNGA as of 2016 June to develop spatially resolved techniques for identifying signatures of active galactic nuclei (AGNs). We identify 303 AGN candidates. The additional spatial dimension imposes challenges in identifying AGNs due to contamination from diffuse ionized gas, extraplanar gas and photoionization by hot stars. We show that the combination of spatially resolved line diagnostic diagrams and additional cuts on H α surface brightness and H α equivalent width can distinguish between AGN-like signatures and high-metallicity galaxies with low-ionization nuclear emission-line regions-like spectra. Low-mass galaxies with high specific star formation rates are particularly difficult to diagnose and routinely show diagnostic line ratios outside of the standard star formation locus. We develop a new diagnostic - the distance from the standard diagnostic line in the line-ratio space - to evaluate the significance of the deviation from the star formation locus. We find 173 galaxies that would not have been selected as AGN candidates based on single-fibre spectral measurements but exhibit photoionization signatures suggestive of AGN activity in the Mapping Nearby Galaxies at APO resolved observations, underscoring the power of large integral field unit surveys. A complete census of these new AGN candidates is necessary to understand their nature and probe the complex co-evolution of supermassive black holes and their hosts.

  19. Atomic hydrogen properties of active galactic nuclei host galaxies: H I in 16 nuclei of galaxies (NUGA) sources

    International Nuclear Information System (INIS)

    Haan, Sebastian; Schinnerer, Eva; Mundell, Carole G.; García-Burillo, Santiago; Combes, Francoise

    2008-01-01

    We present a comprehensive spectroscopic imaging survey of the distribution and kinematics of atomic hydrogen (H I) in 16 nearby spiral galaxies hosting low luminosity active galactic nuclei (AGN), observed with high spectral and spatial resolution (resolution: ∼20'', ∼5 km s –1 ) using the NRAO Very Large Array (VLA). The sample contains a range of nuclear types ranging from Seyfert to star-forming nuclei, and was originally selected for the NUclei of GAlaxies project (NUGA)—a spectrally and spatially resolved interferometric survey of gas dynamics in nearby galaxies designed to identify the fueling mechanisms of AGN and the relation to host galaxy evolution. Here we investigate the relationship between the H I properties of these galaxies, their environment, their stellar distribution, and their AGN type. The large-scale H I morphology of each galaxy is classified as ringed, spiral, or centrally concentrated; comparison of the resulting morphological classification with the AGN type reveals that ring structures are significantly more common in low-ionization narrow emission-line regions (LINER) than in Seyfert host galaxies, suggesting a time evolution of the AGN activity together with the redistribution of the neutral gas. Dynamically disturbed H I disks are also more prevalent in LINER host galaxies than in Seyfert host galaxies. While several galaxies are surrounded by companions (some with associated H I emission), there is no correlation between the presence of companions and the AGN type (Seyfert/LINER).

  20. MID-INFRARED SELECTION OF ACTIVE GALACTIC NUCLEI WITH THE WIDE-FIELD INFRARED SURVEY EXPLORER. II. PROPERTIES OF WISE-SELECTED ACTIVE GALACTIC NUCLEI IN THE NDWFS BOÖTES FIELD

    International Nuclear Information System (INIS)

    Assef, R. J.; Stern, D.; Eisenhardt, P. R. M.; Tsai, C.-W.; Kochanek, C. S.; Blain, A. W.; Brodwin, M.; Brown, M. J. I.; Donoso, E.; Jarrett, T. H.; Yan, L.; Jannuzi, B. T.; Stanford, S. A.; Wu, J.

    2013-01-01

    Stern et al. presented a study of Wide-field Infrared Survey Explorer (WISE) selection of active galactic nuclei (AGNs) in the 2 deg 2 COSMOS field, finding that a simple criterion W1-W2 ≥ 0.8 provides a highly reliable and complete AGN sample for W2 2 NOAO Deep Wide-Field Survey Boötes field which also has considerably deeper WISE observations than the COSMOS field, and find that this simple color cut significantly loses reliability at fainter fluxes. We define a modified selection criterion combining the W1–W2 color and the W2 magnitude to provide highly reliable or highly complete AGN samples for fainter WISE sources. In particular, we define a color-magnitude cut that finds 130 ± 4 deg –2 AGN candidates for W2 AGN ∼ 3 × 10 44 erg s –1 , 29% ± 7% of AGNs are observed as Type 1, while at ∼4 × 10 45 erg s –1 the fraction is 64% ± 13%. The distribution of obscuration values suggests that dust in the torus is present as both a diffuse medium and in optically thick clouds

  1. The Galactic magnetic fields

    International Nuclear Information System (INIS)

    Han Jinlin

    2006-01-01

    A good progress has been made on studies of Galactic magnetic fields in last 10 years. I describe what we want to know about the Galactic magnetic fields, and then review we current knowledge about magnetic fields in the Galactic disk, the Galactic halo and the field strengths. I also listed many unsolved problems on this area

  2. Unification of type-II strings and T duality.

    Science.gov (United States)

    Hohm, Olaf; Kwak, Seung Ki; Zwiebach, Barton

    2011-10-21

    We present a unified description of the low-energy limits of type-II string theories. This is achieved by a formulation that doubles the space-time coordinates in order to realize the T-duality group O(10,10) geometrically. The Ramond-Ramond fields are described by a spinor of O(10,10), which couples to the gravitational fields via the Spin(10,10) representative of the so-called generalized metric. This theory, which is supplemented by a T-duality covariant self-duality constraint, unifies the type-II theories in that each of them is obtained for a particular subspace of the doubled space. © 2011 American Physical Society

  3. Hearing loss in Usher syndrome type II is nonprogressive.

    Science.gov (United States)

    Reisser, Christoph F V; Kimberling, William J; Otterstedde, Christian R

    2002-12-01

    Usher syndrome is an autosomal recessive disorder characterized by sensorineural hearing loss and progressive visual loss secondary to retinitis pigmentosa. In the literature, a possible progression of the moderate to severe hearing loss in Usher syndrome type II (Usher II) is controversial. We studied the development of the hearing loss of 125 patients with a clinical diagnosis of Usher syndrome type II intraindividually and interindividually by repeatedly performing complete audiological and neuro-otologic examinations. Our data show a very characteristic slope of the hearing curve in all Usher II patients and no clinically relevant progression of the hearing loss over up to 17 years. The subjective impression of a deterioration of the communicative abilities of Usher II patients must therefore be attributed to the progressive visual loss. The patients should be reassured that changes in their hearing abilities are unlikely and should be provided with optimally fitted modern hearing aids.

  4. Theoretical models for Type I and Type II supernova

    International Nuclear Information System (INIS)

    Woosley, S.E.; Weaver, T.A.

    1985-01-01

    Recent theoretical progress in understanding the origin and nature of Type I and Type II supernovae is discussed. New Type II presupernova models characterized by a variety of iron core masses at the time of collapse are presented and the sensitivity to the reaction rate 12 C(α,γ) 16 O explained. Stars heavier than about 20 M/sub solar/ must explode by a ''delayed'' mechanism not directly related to the hydrodynamical core bounce and a subset is likely to leave black hole remnants. The isotopic nucleosynthesis expected from these massive stellar explosions is in striking agreement with the sun. Type I supernovae result when an accreting white dwarf undergoes a thermonuclear explosion. The critical role of the velocity of the deflagration front in determining the light curve, spectrum, and, especially, isotopic nucleosynthesis in these models is explored. 76 refs., 8 figs

  5. UBVRIz LIGHT CURVES OF 51 TYPE II SUPERNOVAE

    International Nuclear Information System (INIS)

    Galbany, Lluis; Hamuy, Mario; Jaeger, Thomas de; Moraga, Tania; González-Gaitán, Santiago; Gutiérrez, Claudia P.; Phillips, Mark M.; Morrell, Nidia I.; Thomas-Osip, Joanna; Suntzeff, Nicholas B.; Maza, José; González, Luis; Antezana, Roberto; Wishnjewski, Marina; Krisciunas, Kevin; Krzeminski, Wojtek; McCarthy, Patrick; Anderson, Joseph P.; Stritzinger, Maximilian; Folatelli, Gastón

    2016-01-01

    We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986–2003: the Cerro Tololo Supernova Survey, the Calán/Tololo Supernova Program (C and T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values

  6. Instability in the magnetic field penetration in type II superconductors

    International Nuclear Information System (INIS)

    Oliveira, Isaías G. de

    2015-01-01

    Under the view of the time-dependent Ginzburg–Landau theory we have investigated the penetration of the magnetic field in the type II superconductors. We show that the single vortices, situated along the borderline, between the normal region channel and the superconducting region, can escape to regions still empty of vortices. We show that the origin of this process is the repulsive nature of vortex–vortex interaction, in addition to the non-homogeneous distribution of the vortices along the normal region channel. Using London theory we explain the extra gain of kinetic energy by the vortices situated along this borderline. - Highlights: • TDGL is used to study the magnetic field penetration in type II superconductors. • Instability process is found during the magnetic field penetration. • Vortices along the front of the normal region escape to superconducting region. • We explain the extra-gain of kinetic energy by vortices along the borderline

  7. UBVRIz LIGHT CURVES OF 51 TYPE II SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Galbany, Lluis; Hamuy, Mario; Jaeger, Thomas de; Moraga, Tania; González-Gaitán, Santiago; Gutiérrez, Claudia P. [Millennium Institute of Astrophysics, Universidad de Chile (Chile); Phillips, Mark M.; Morrell, Nidia I.; Thomas-Osip, Joanna [Carnegie Observatories, Las Campanas Observatory, Casilla 60, La Serena (Chile); Suntzeff, Nicholas B. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Maza, José; González, Luis; Antezana, Roberto; Wishnjewski, Marina [Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago (Chile); Krisciunas, Kevin [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A. and M. University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States); Krzeminski, Wojtek [N. Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa (Poland); McCarthy, Patrick [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Anderson, Joseph P. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago (Chile); Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University (Denmark); Folatelli, Gastón, E-mail: lgalbany@das.uchile.cl [Instituto de Astrofísica de La Plata (IALP, CONICET) (Argentina); and others

    2016-02-15

    We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986–2003: the Cerro Tololo Supernova Survey, the Calán/Tololo Supernova Program (C and T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values.

  8. Type II intrapancreatic choledochal malignant cyst in adults: duodenopancreatectomy

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Jiménez-Ballester

    2014-03-01

    Full Text Available A 62-year-old female patient was admitted for abdominal pain and vomiting. Imaging tests revealed a solid-cystic lesion at the head of the pancreas communicating with the distal bile duct. A Todani type II choledochal cyst was diagnosed with neoplastic degeneration after cytological diagnosis with endoscopic ultrasound-guided puncture. The patient was treated with a cephalic duodenopancreatectomy with curative intention.

  9. Progenitors of low-luminosity Type II-Plateau supernovae

    Science.gov (United States)

    Lisakov, Sergey M.; Dessart, Luc; Hillier, D. John; Waldman, Roni; Livne, Eli

    2018-01-01

    The progenitors of low-luminosity Type II-Plateau supernovae (SNe II-P) are believed to be red supergiant (RSG) stars, but there is much disparity in the literature concerning their mass at core collapse and therefore on the main sequence. Here, we model the SN radiation arising from the low-energy explosion of RSG stars of 12, 25 and 27 M⊙ on the main sequence and formed through single star evolution. Despite the narrow range in ejecta kinetic energy (2.5-4.2 × 1050 erg) in our model set, the SN observables from our three models are significantly distinct, reflecting the differences in progenitor structure (e.g. surface radius, H-rich envelope mass and He-core mass). Our higher mass RSG stars give rise to Type II SNe that tend to have bluer colours at early times, a shorter photospheric phase, and a faster declining V-band light curve (LC) more typical of Type II-linear SNe, in conflict with the LC plateau observed for low-luminosity SNe II. The complete fallback of the CO core in the low-energy explosions of our high-mass RSG stars prevents the ejection of any 56Ni (nor any core O or Si), in contrast to low-luminosity SNe II-P, which eject at least 0.001 M⊙ of 56Ni. In contrast to observations, Type II SN models from higher mass RSGs tend to show an H α absorption that remains broad at late times (due to a larger velocity at the base of the H-rich envelope). In agreement with the analyses of pre-explosion photometry, we conclude that low-luminosity SNe II-P likely arise from low-mass rather than high-mass RSG stars.

  10. Tractional retinal detachment in Usher syndrome type II.

    Science.gov (United States)

    Rani, Alka; Pal, Nikhil; Azad, Raj Vardhan; Sharma, Yog Raj; Chandra, Parijat; Vikram Singh, Deependra

    2005-08-01

    Retinal detachment is a rare complication in patients with retinitis pigmentosa. A case is reported of tractional retinal detachment in a patient with retinitis pigmentosa and sensorineural hearing loss, which was diagnosed as Usher syndrome type II. Because of the poor visual prognosis, the patient refused surgery in that eye. Tractional retinal detachment should be added to the differential diagnoses of visual loss in patients with retinitis pigmentosa.

  11. Closed Timelike Curves in Type II Non-Vacuum Spacetime

    International Nuclear Information System (INIS)

    Ahmed, Faizuddin

    2017-01-01

    Here we present a cyclicly symmetric non-vacuum spacetime, admitting closed timelike curves (CTCs) which appear after a certain instant of time, i.e., a time-machine spacetime. The spacetime is asymptotically flat, free-from curvature singularities and a four-dimensional extension of the Misner space in curved spacetime. The spacetime is of type II in the Petrov classification scheme and the matter field pure radiation satisfy the energy condition. (paper)

  12. Nephrocalcinosis as adult presentation of Bartter syndrome type II.

    Science.gov (United States)

    Huang, L; Luiken, G P M; van Riemsdijk, I C; Petrij, F; Zandbergen, A A M; Dees, A

    2014-02-01

    Bartter syndrome consists a group of rare autosomal-recessive renal tubulopathies characterised by renal salt wasting, hypokalaemic metabolic alkalosis, hypercalciuria and hyperreninaemic hyperaldosteronism. It is classified into five types. Mutations in the KCNJ1 gene (classified as type II) usually cause the neonatal form of Bartter syndrome. We describe an adult patient with a homozygous KCNJ1 mutation resulting in a remarkably mild phenotype of neonatal type Bartter syndrome.

  13. Effects of Oral Administration of Type II Collagen on Rheumatoid Arthritis

    Science.gov (United States)

    Trentham, David E.; Dynesius-Trentham, Roselynn A.; Orav, E. John; Combitchi, Daniel; Lorenzo, Carlos; Sewell, Kathryn Lea; Hafler, David A.; Weiner, Howard L.

    1993-09-01

    Rheumatoid arthritis is an inflammatory synovial disease thought to involve T cells reacting to an antigen within the joint. Type II collagen is the major protein in articular cartilage and is a potential autoantigen in this disease. Oral tolerization to autoantigens suppresses animal models of T cell-mediated autoimmune disease, including two models of rheumatoid arthritis. In this randomized, double-blind trial involving 60 patients with severe, active rheumatoid arthritis, a decrease in the number of swollen joints and tender joints occurred in subjects fed chicken type II collagen for 3 months but not in those that received a placebo. Four patients in the collagen group had complete remission of the disease. No side effects were evident. These data demonstrate clinical efficacy of an oral tolerization approach for rheumatoid arthritis.

  14. THE SPITZER MID-INFRARED ACTIVE GALACTIC NUCLEUS SURVEY. I. OPTICAL AND NEAR-INFRARED SPECTROSCOPY OF OBSCURED CANDIDATES AND NORMAL ACTIVE GALACTIC NUCLEI SELECTED IN THE MID-INFRARED

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Ridgway, S. E. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Gates, E. L. [UCO/Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Nielsen, D. M. [Department of Astronomy, University of Wisconsin, 475 N. Charter Street, Madison, WI 53706 (United States); Petric, A. O. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Sajina, A. [Department of Physics and Astronomy, Tuffs University, 212 College Avenue, Medford, MA 02155 (United States); Urrutia, T. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Cox Drews, S. [946 Mangrove Avenue 102, Sunnyvale, CA 94086 (United States); Harrison, C. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Seymour, N. [CSIRO, P.O. Box 76, Epping, NSW 1710 (Australia); Storrie-Lombardi, L. J. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2013-10-01

    We present the results of a program of optical and near-infrared spectroscopic follow-up of candidate active galactic nuclei (AGNs) selected in the mid-infrared. This survey selects both normal and obscured AGNs closely matched in luminosity across a wide range, from Seyfert galaxies with bolometric luminosities L {sub bol} ∼ 10{sup 10} L {sub ☉} to highly luminous quasars (L {sub bol} ∼ 10{sup 14} L {sub ☉}), all with redshifts ranging from 0 to 4.3. Samples of candidate AGNs were selected with mid-infrared color cuts at several different 24 μm flux density limits to ensure a range of luminosities at a given redshift. The survey consists of 786 candidate AGNs and quasars, of which 672 have spectroscopic redshifts and classifications. Of these, 137 (20%) are type 1 AGNs with blue continua, 294 (44%) are type 2 objects with extinctions A{sub V} ∼> 5 toward their AGNs, 96 (14%) are AGNs with lower extinctions (A{sub V} ∼ 1), and 145 (22%) have redshifts, but no clear signs of AGN activity in their spectra. Of the survey objects 50% have L {sub bol} > 10{sup 12} L {sub ☉}, in the quasar regime. We present composite spectra for type 2 quasars and objects with no signs of AGN activity in their spectra. We also discuss the mid-infrared—emission-line luminosity correlation and present the results of cross correlations with serendipitous X-ray and radio sources. The results show that: (1) obscured objects dominate the overall AGN population, (2) mid-infrared selected AGN candidates exist which lack AGN signatures in their optical spectra but have AGN-like X-ray or radio counterparts, and (3) X-ray and optical classifications of obscured and unobscured AGNs often differ.

  15. Type II superconductivity in SrPd2Ge2

    International Nuclear Information System (INIS)

    Samuely, T; Szabó, P; Pribulová, Z; Samuely, P; Sung, N H; Cho, B K; Klein, T; Cambel, V; Rodrigo, J G

    2013-01-01

    Previous investigations have shown that SrPd 2 Ge 2 , a compound isostructural with ‘122’ iron pnictides but iron and pnictogen free, is a conventional superconductor with a single s-wave energy gap and a strongly three-dimensional electronic structure. In this work we reveal the Abrikosov vortex lattice formed in SrPd 2 Ge 2 when exposed to magnetic field by means of scanning tunneling microscopy and spectroscopy. Moreover, by examining the differential conductance spectra across a vortex and estimating the upper and lower critical magnetic fields by tunneling spectroscopy and local magnetization measurements, we show that SrPd 2 Ge 2 is a strong type II superconductor with κ ≫ 2 −1/2 . Also, we compare the differential conductance spectra in various magnetic fields to the pair-breaking model of Maki and de Gennes for a dirty limit type II superconductor in the gapless region. This way we demonstrate that the type II superconductivity is induced by the sample being in the dirty limit, while in the clean limit it would be a type I superconductor with κ ≪ 2 −1/2 , in concordance with our previous study (Kim et al (2012) Phys. Rev. B 85 014520). (paper)

  16. Type II restriction endonucleases—a historical perspective and more

    Science.gov (United States)

    Pingoud, Alfred; Wilson, Geoffrey G.; Wende, Wolfgang

    2014-01-01

    This article continues the series of Surveys and Summaries on restriction endonucleases (REases) begun this year in Nucleic Acids Research. Here we discuss ‘Type II’ REases, the kind used for DNA analysis and cloning. We focus on their biochemistry: what they are, what they do, and how they do it. Type II REases are produced by prokaryotes to combat bacteriophages. With extreme accuracy, each recognizes a particular sequence in double-stranded DNA and cleaves at a fixed position within or nearby. The discoveries of these enzymes in the 1970s, and of the uses to which they could be put, have since impacted every corner of the life sciences. They became the enabling tools of molecular biology, genetics and biotechnology, and made analysis at the most fundamental levels routine. Hundreds of different REases have been discovered and are available commercially. Their genes have been cloned, sequenced and overexpressed. Most have been characterized to some extent, but few have been studied in depth. Here, we describe the original discoveries in this field, and the properties of the first Type II REases investigated. We discuss the mechanisms of sequence recognition and catalysis, and the varied oligomeric modes in which Type II REases act. We describe the surprising heterogeneity revealed by comparisons of their sequences and structures. PMID:24878924

  17. Expression and purification of sea raven type II antifreeze protein from Drosophila melanogaster S2 cells.

    Science.gov (United States)

    Scotter, Andrew J; Kuntz, Douglas A; Saul, Michelle; Graham, Laurie A; Davies, Peter L; Rose, David R

    2006-06-01

    We present a system for the expression and purification of recombinant sea raven type II antifreeze protein, a cysteine-rich, C-type lectin-like globular protein that has proved to be a difficult target for recombinant expression and purification. The cDNAs encoding the pro- and mature forms of the sea raven protein were cloned into a modified pMT Drosophila expression vector. These constructs produced N-terminally His(6)-tagged pro- and mature forms of the type II antifreeze protein under the control of a metallothionein promoter when transfected into Drosophila melanogaster S2 cells. Upon induction of stable cell lines the two proteins were expressed at high levels and secreted into the medium. The proteins were then purified from the cell medium in a simple and rapid protocol using immobilized metal affinity chromatography and specific protease cleavage by tobacco etch virus protease. The proteins demonstrated antifreeze activity indistinguishable from that of wild-type sea raven antifreeze protein purified from serum as illustrated by ice affinity purification, ice crystal morphology, and their ability to inhibit ice crystal growth. This expression and purification system gave yields of 95 mg/L of fully active mature sea raven type II AFP and 9.6 mg/L of the proprotein. This surpasses all previous attempts to express this protein in Escherichia coli, baculovirus-infected fall armyworm cells and Pichia pastoris and will provide sufficient protein for structural analysis.

  18. Automatic recognition of coronal type II radio bursts: The ARBIS 2 method and first observations

    Science.gov (United States)

    Lobzin, Vasili; Cairns, Iver; Robinson, Peter; Steward, Graham; Patterson, Garth

    Major space weather events such as solar flares and coronal mass ejections are usually accompa-nied by solar radio bursts, which can potentially be used for real-time space weather forecasts. Type II radio bursts are produced near the local plasma frequency and its harmonic by fast electrons accelerated by a shock wave moving through the corona and solar wind with a typi-cal speed of 1000 km s-1 . The coronal bursts have dynamic spectra with frequency gradually falling with time and durations of several minutes. We present a new method developed to de-tect type II coronal radio bursts automatically and describe its implementation in an extended Automated Radio Burst Identification System (ARBIS 2). Preliminary tests of the method with spectra obtained in 2002 show that the performance of the current implementation is quite high, ˜ 80%, while the probability of false positives is reasonably low, with one false positive per 100-200 hr for high solar activity and less than one false event per 10000 hr for low solar activity periods. The first automatically detected coronal type II radio bursts are also presented. ARBIS 2 is now operational with IPS Radio and Space Services, providing email alerts and event lists internationally.

  19. THERMAL AND DYNAMICAL PROPERTIES OF GAS ACCRETING ONTO A SUPERMASSIVE BLACK HOLE IN AN ACTIVE GALACTIC NUCLEUS

    International Nuclear Information System (INIS)

    Mościbrodzka, M.; Proga, D.

    2013-01-01

    We study stability of gas accretion in active galactic nuclei (AGNs). Our grid-based simulations cover a radial range from 0.1 to 200 pc, which may enable linking the galactic/cosmological simulations with small-scale black hole (BH) accretion models within a few hundreds of Schwarzschild radii. Here, as in previous studies by our group, we include gas radiative cooling as well as heating by a sub-Eddington X-ray source near the central supermassive BH of 10 8 M ☉ . Our theoretical estimates and simulations show that for the X-ray luminosity, L X ∼ 0.008 L Edd , the gas is thermally and convectively unstable within the computational domain. In the simulations, we observe that very tiny fluctuations in an initially smooth, spherically symmetric, accretion flow, grow first linearly and then nonlinearly. Consequently, an initially one-phase flow relatively quickly transitions into a two-phase/cold-hot accretion flow. For L X = 0.015 L Edd or higher, the cold clouds continue to accrete but in some regions of the hot phase, the gas starts to move outward. For L X Edd , the cold phase contribution to the total mass accretion rate only moderately dominates over the hot phase contribution. This result might have some consequences for cosmological simulations of the so-called AGN feedback problem. Our simulations confirm the previous results of Barai et al. who used smoothed particle hydrodynamic (SPH) simulations to tackle the same problem. Here, however, because we use a grid-based code to solve equations in one dimension and two dimensions, we are able to follow the gas dynamics at much higher spacial resolution and for longer time compared with the three-dimensional SPH simulations. One of the new features revealed by our simulations is that the cold condensations in the accretion flow initially form long filaments, but at the later times, those filaments may break into smaller clouds advected outward within the hot outflow. Therefore, these simulations may serve as

  20. Failed Radiatively Accelerated Dusty Outflow Model of the Broad Line Region in Active Galactic Nuclei. I. Analytical Solution

    Energy Technology Data Exchange (ETDEWEB)

    Czerny, B.; Panda, S.; Wildy, C.; Sniegowska, M. [Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Li, Yan-Rong; Wang, J.-M. [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China); Hryniewicz, K.; Sredzinska, J. [Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716 Warsaw (Poland); Karas, V., E-mail: bcz@cft.edu.pl [Astronomical Institute, Academy of Sciences, Bocni II 1401, CZ-141 00 Prague (Czech Republic)

    2017-09-10

    The physical origin of the broad line region in active galactic nuclei is still unclear despite many years of observational studies. The reason is that the region is unresolved, and the reverberation mapping results imply a complex velocity field. We adopt a theory-motivated approach to identify the principal mechanism responsible for this complex phenomenon. We consider the possibility that the role of dust is essential. We assume that the local radiation pressure acting on the dust in the accretion disk atmosphere launches the outflow of material, but higher above the disk the irradiation from the central parts causes dust evaporation and a subsequent fallback. This failed radiatively accelerated dusty outflow is expected to represent the material forming low ionization lines. In this paper we formulate simple analytical equations to describe the cloud motion, including the evaporation phase. The model is fully described just by the basic parameters of black hole mass, accretion rate, black hole spin, and viewing angle. We study how the spectral line generic profiles correspond to this dynamic. We show that the virial factor calculated from our model strongly depends on the black hole mass in the case of enhanced dust opacity, and thus it then correlates with the line width. This could explain why the virial factor measured in galaxies with pseudobulges differs from that obtained from objects with classical bulges, although the trend predicted by the current version of the model is opposite to the observed trend.

  1. Fermi-LAT γ-ray anisotropy and intensity explained by unresolved radio-loud active galactic nuclei

    International Nuclear Information System (INIS)

    Mauro, Mattia Di; Cuoco, Alessandro; Donato, Fiorenza; Siegal-Gaskins, Jennifer M.

    2014-01-01

    Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic γ-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the γ-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations

  2. THE ROLE OF THE ACCRETION DISK, DUST, AND JETS IN THE IR EMISSION OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R. E. [Gemini Observatory, Northern Operations Center, 670 N. A' ohoku Place, Hilo, HI 96720 (United States); Ramos Almeida, C. [Instituto de Astrofísica de Canarias, C/Vía Láctea, s/n, E-38205 La Laguna, Tenerife (Spain); Levenson, N. A. [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Nemmen, R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Alonso-Herrero, A., E-mail: rmason@gemini.edu [Instituto de Física de Cantabria, CSIC-UC, Avenida de los Castros s/n, E-39005 Santander (Spain)

    2013-11-10

    We use recent high-resolution infrared (IR; 1-20 μm) photometry to examine the origin of the IR emission in low-luminosity active galactic nuclei (LLAGN). The data are compared with published model fits that describe the spectral energy distribution (SED) of LLAGN in terms of an advection-dominated accretion flow, truncated thin accretion disk, and jet. The truncated disk in these models is usually not luminous enough to explain the observed IR emission, and in all cases its spectral shape is much narrower than the broad IR peaks in the data. Synchrotron radiation from the jet appears to be important in very radio-loud nuclei, but the detection of strong silicate emission features in many objects indicates that dust must also contribute. We investigate this point by fitting the IR SED of NGC 3998 using dusty torus and optically thin (τ{sub mid-IR} ∼ 1) dust shell models. While more detailed modeling is necessary, these initial results suggest that dust may account for the nuclear mid-IR emission of many LLAGN.

  3. THE INTRINSIC EDDINGTON RATIO DISTRIBUTION OF ACTIVE GALACTIC NUCLEI IN STAR-FORMING GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Mackenzie L.; Hickox, Ryan C.; Black, Christine S.; Hainline, Kevin N.; DiPompeo, Michael A. [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Goulding, Andy D. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2016-07-20

    An important question in extragalactic astronomy concerns the distribution of black hole accretion rates of active galactic nuclei (AGNs). Based on observations at X-ray wavelengths, the observed Eddington ratio distribution appears as a power law, while optical studies have often yielded a lognormal distribution. There is increasing evidence that these observed discrepancies may be due to contamination by star formation and other selection effects. Using a sample of galaxies from the Sloan Digital Sky Survey Data Release 7, we test whether or not an intrinsic Eddington ratio distribution that takes the form of a Schechter function is consistent with previous work suggesting that young galaxies in optical surveys have an observed lognormal Eddington ratio distribution. We simulate the optical emission line properties of a population of galaxies and AGNs using a broad, instantaneous luminosity distribution described by a Schechter function near the Eddington limit. This simulated AGN population is then compared to observed galaxies via their positions on an emission line excitation diagram and Eddington ratio distributions. We present an improved method for extracting the AGN distribution using BPT diagnostics that allows us to probe over one order of magnitude lower in Eddington ratio, counteracting the effects of dilution by star formation. We conclude that for optically selected AGNs in young galaxies, the intrinsic Eddington ratio distribution is consistent with a possibly universal, broad power law with an exponential cutoff, as this distribution is observed in old, optically selected galaxies and X-rays.

  4. Fermi-LAT γ-ray anisotropy and intensity explained by unresolved radio-loud active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, Mattia Di; Cuoco, Alessandro; Donato, Fiorenza [Dipartimento di Fisica, Università di Torino, via P. Giuria 1, Torino, 10125 Italy (Italy); Siegal-Gaskins, Jennifer M., E-mail: mattia.dimauro@to.infn.it, E-mail: alessandro.cuoco@to.infn.it, E-mail: donato@to.infn.it, E-mail: jsg@tapir.caltech.edu [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, 91125 (United States)

    2014-11-01

    Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic γ-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the γ-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations.

  5. The Atacama Cosmology Telescope: Dusty Star-Forming Galaxies and Active Galactic Nuclei in the Southern Survey

    Science.gov (United States)

    Marsden, Danica; Gralla, Megan; Marriage, Tobias A.; Switzer, Eric R.; Partridge, Bruce; Massardi, Marcella; Morales, Gustavo; Addison, Graeme; Bond, J. Richard; Crighton, Devin; hide

    2014-01-01

    We present a catalogue of 191 extragalactic sources detected by the Atacama Cosmology Telescope (ACT) at 148 and/or 218 GHz in the 2008 Southern survey. Flux densities span 14 -1700 mJy, and we use source spectral indices derived using ACT-only data to divide our sources into two subpopulations: 167 radio galaxies powered by central active galactic nuclei (AGN) and 24 dusty star-forming galaxies (DSFGs). We cross-identify 97 per cent of our sources (166 of the AGN and 19 of the DSFGs) with those in currently available catalogues. When combined with flux densities from the Australia Telescope 20 GHz survey and follow-up observations with the Australia Telescope Compact Array, the synchrotron-dominated population is seen to exhibit a steepening of the slope of the spectral energy distribution from 20 to 148 GHz, with the trend continuing to 218 GHz. The ACT dust-dominated source population has a median spectral index, A(sub 148-218), of 3.7 (+0.62 or -0.86), and includes both local galaxies and sources with redshift around 6. Dusty sources with no counterpart in existing catalogues likely belong to a recently discovered subpopulation of DSFGs lensed by foreground galaxies or galaxy groups.

  6. EVOLUTION OF WARPED ACCRETION DISKS IN ACTIVE GALACTIC NUCLEI. I. ROLES OF FEEDING AT THE OUTER BOUNDARIES

    International Nuclear Information System (INIS)

    Li, Yan-Rong; Wang, Jian-Min; Cheng, Cheng; Qiu, Jie

    2013-01-01

    We investigate the alignment processes of spinning black holes and their surrounding warped accretion disks in a frame of two different types of feeding at the outer boundaries. We consider (1) fixed flows in which gas is continually fed with a preferred angular momentum, and (2) free flows in which there is no gas supply and the disks diffuse freely at their outer edges. As expected, we find that for the cases of fixed flows the black hole disk systems always align on timescales of several 10 6 yr, irrespective of the initial inclinations. If the initial inclination angles are larger than π/2, the black hole accretion transits from retrograde to prograde fashion, and the accreted mass onto the black holes during these two phases is comparable. On the other hand, for the cases of free flows, both alignments and anti-alignments can occur, depending on the initial inclinations and the ratios of the angular momentum of the disks to that of the black holes. In such cases, the disks will be consumed within timescales of 10 6 yr by black holes accreting at the Eddington limit. We propose that there is a close connection between the black hole spin and the lifetime for which the feeding persists, which determines the observable episodic lifetimes of active galactic nuclei. We conclude that careful inclusion of the disk feeding at the outer boundaries is crucial for modeling the evolution of the black hole spin.

  7. Oscillatory patterns in the light curves of five long-term monitored type 1 active galactic nuclei

    Science.gov (United States)

    Kovačević, Andjelka B.; Pérez-Hernández, Ernesto; Popović, Luka Č.; Shapovalova, Alla I.; Kollatschny, Wolfram; Ilić, Dragana

    2018-04-01

    New combined data of five well-known type 1 active galactic nuclei (AGNs) are probed with a novel hybrid method in a search for oscillatory behaviour. Additional analysis of artificial light curves obtained from the coupled oscillatory models gives confirmation for detected periods that could have a physical background. We find periodic variations in the long-term light curves of 3C 390.3, NGC 4151 and NGC 5548, and E1821 + 643, with correlation coefficients larger than 0.6. We show that the oscillatory patterns of two binary black hole candidates, NGC 5548 and E1821 + 643, correspond to qualitatively different dynamical regimes of chaos and stability, respectively. We demonstrate that the absence of oscillatory patterns in Arp 102B could be the result of a weak coupling between oscillatory mechanisms. This is the first good evidence that 3C 390.3 and Arp 102B, categorized as double-peaked Balmer line objects, have qualitative different dynamics. Our analysis shows a novelty in the oscillatory dynamical patterns of the light curves of these type 1 AGNs.

  8. Bulgeless galaxies at intermediate redshift: Sample selection, color properties, and the existence of powerful active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Bizzocchi, Luca; Leonardo, Elvira; Grossi, Marco; Afonso, José; Fernandes, Cristina; Retrê, João [Centro de Astronomia e Astrofísica da Universidade de Lisboa, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisbon (Portugal); Filho, Mercedes E.; Lobo, Catarina [Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Griffith, Roger L. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Anton, Sonia [Centro de Investigação em Ciências Geo-Espaciais, Faculdade de Ciências da Universidade do Porto, Porto (Portugal); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Brinchmann, Jarle [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Henriques, Bruno [Max-Planck-Institut für Astrophysik, Karl Schwarzschild Straße 1, D-85748 Garching bei München (Germany); Messias, Hugo [Departamento de astronomía, Av. Esteban Iturra 6to piso, Facultad de Ciencias Físicas y Matemáticas, Universidad de Concepción (Chile)

    2014-02-10

    We present a catalog of bulgeless galaxies, which includes 19,225 objects selected in four of the deepest, largest multi-wavelength data sets available—COSMOS, AEGIS, GEMS, and GOODS—at intermediate redshift (0.4 ≤ z ≤ 1.0). The morphological classification was provided by the Advanced Camera for Surveys General Catalog (ACS-GC), which used publicly available data obtained with the ACS instrument on the Hubble Space Telescope. Rest-frame photometric quantities were derived using kcorrect. We analyze the properties of the sample and the evolution of pure-disk systems with redshift. Very massive [log (M {sub *}/M {sub ☉}) > 10.5] bulgeless galaxies contribute to ∼30% of the total galaxy population number density at z ≥ 0.7, but their number density drops substantially with decreasing redshift. We show that only a negligible fraction of pure disks appear to be quiescent systems, and red sequence bulgeless galaxies show indications of dust-obscured star formation. X-ray catalogs were used to search for X-ray emission within our sample. After visual inspection and detailed parametric morphological fitting we identify 30 active galactic nuclei (AGNs) that reside in galaxies without a classical bulge. The finding of such peculiar objects at intermediate redshift shows that while AGN growth in merger-free systems is a rare event (0.2% AGN hosts in this sample of bulgeless galaxies), it can indeed happen relatively early in the history of the universe.

  9. THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS

    International Nuclear Information System (INIS)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C.; Horne, Keith; Bentz, M. C.; Denney, K. D.; Siverd, R.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Bord, D. J.; Che, X.

    2013-01-01

    We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the Hβ emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II λ4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

  10. THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS

    Energy Technology Data Exchange (ETDEWEB)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Ave, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Denney, K. D. [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Siverd, R. [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); and others

    2013-02-10

    We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H{beta} emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II {lambda}4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

  11. Enhancement of Feedback Efficiency by Active Galactic Nucleus Outflows via the Magnetic Tension Force in the Inhomogeneous Interstellar Medium

    Energy Technology Data Exchange (ETDEWEB)

    Asahina, Yuta; Ohsuga, Ken [National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Nomura, Mariko, E-mail: asahina@cfca.jp [Keio University, Hiyoshi, Kohoku, Yokohama, Kanagawa 223-8522 (Japan)

    2017-05-01

    By performing three-dimensional magnetohydrodynamics simulations of subrelativistic jets and disk winds propagating into the magnetized inhomogeneous interstellar medium (ISM), we investigate the magnetic effects on the active galactic nucleus feedback. Our simulations reveal that the magnetic tension force promotes the acceleration of the dense gas clouds, since the magnetic field lines, which are initially straight, bend around the gas clouds. In the jet models, the velocity dispersion of the clouds increases with an increase in the initial magnetic fields. The increment of the kinetic energy of the clouds is proportional to the initial magnetic fields, implying that the magnetic tension force increases the energy conversion efficiency from the jet to the gas clouds. Through simulations of the mildly collimated disk wind and the funnel-shaped disk wind, we confirm that such an enhancement of the energy conversion efficiency via the magnetic fields appears even if the energy is injected via the disk winds. The enhancement of the acceleration of the dense part of the magnetized ISM via the magnetic tension force will occur wherever the magnetized inhomogeneous matter is blown away.

  12. THE RELATION OF OPTICAL/ULTRAVIOLET AND X-RAY EMISSION IN LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Xu Yadi

    2011-01-01

    We study the relation of optical/UV and X-ray emission in the low luminosity active galactic nuclei (LLAGNs), using a sample of 49 sources including 28 local Seyfert galaxies and 21 low-ionization nuclear emission-line regions with optical/UV spectral luminosity at wavelength λ = 2500 A, 23.0 ≤ log L ν(2500A) (erg s -1 Hz -1 ) ≤ 27.7, and X-ray spectral luminosity at 2 keV, 20.5 ≤ log L ν(2keV) ≤ 25.3. Strong correlations are found between the X-ray luminosity and the optical/UV-to-X-ray index, α ox , with the optical/UV luminosity, with slopes very similar to the findings for the luminous AGNs in previous works. The correlation between α ox and L ν(2keV) is very weak, as is that found for the luminous AGNs in the majority of previous similar works. We also study the relation between α ox and the Eddington ratio L bol /L Edd for our sample and find a significant anti-correlation for the sources with L bol /L Edd ∼ -3 , which is opposite to the correlation between the two variables for the luminous AGNs. Using the advection-dominated accretion flow (ADAF) model, we roughly reproduce this anti-correlationship for the two variables for the LLAGNs. This result strongly supports the ADAF as a candidate for the accretion mode in LLAGNs.

  13. The near-infrared broad emission line region of active galactic nuclei - II. The 1-μm continuum

    Science.gov (United States)

    Landt, Hermine; Elvis, Martin; Ward, Martin J.; Bentz, Misty C.; Korista, Kirk T.; Karovska, Margarita

    2011-06-01

    We use quasi-simultaneous near-infrared (near-IR) and optical spectroscopy from four observing runs to study the continuum around 1 μm in 23 well-known broad emission line active galactic nuclei (AGN). We show that, after correcting the optical spectra for host galaxy light, the AGN continuum around this wavelength can be approximated by the sum of mainly two emission components, a hot dust blackbody and an accretion disc. The accretion disc spectrum appears to dominate the flux at ˜ 1 μm, which allows us to derive a relation for estimating AGN black hole masses based on the near-IR virial product. This result also means that a near-IR reverberation programme can determine the AGN state independent of simultaneous optical spectroscopy. On average we derive hot dust blackbody temperatures of ˜1400 K, a value close to the sublimation temperature of silicate dust grains, and relatively low hot dust covering factors of ˜7 per cent. Our preliminary variability studies indicate that in most sources, the hot dust emission responds to changes in the accretion disc flux with the expected time lag; however, a few sources show a behaviour that can be attributed to dust destruction.

  14. Enhancement of Feedback Efficiency by Active Galactic Nucleus Outflows via the Magnetic Tension Force in the Inhomogeneous Interstellar Medium

    International Nuclear Information System (INIS)

    Asahina, Yuta; Ohsuga, Ken; Nomura, Mariko

    2017-01-01

    By performing three-dimensional magnetohydrodynamics simulations of subrelativistic jets and disk winds propagating into the magnetized inhomogeneous interstellar medium (ISM), we investigate the magnetic effects on the active galactic nucleus feedback. Our simulations reveal that the magnetic tension force promotes the acceleration of the dense gas clouds, since the magnetic field lines, which are initially straight, bend around the gas clouds. In the jet models, the velocity dispersion of the clouds increases with an increase in the initial magnetic fields. The increment of the kinetic energy of the clouds is proportional to the initial magnetic fields, implying that the magnetic tension force increases the energy conversion efficiency from the jet to the gas clouds. Through simulations of the mildly collimated disk wind and the funnel-shaped disk wind, we confirm that such an enhancement of the energy conversion efficiency via the magnetic fields appears even if the energy is injected via the disk winds. The enhancement of the acceleration of the dense part of the magnetized ISM via the magnetic tension force will occur wherever the magnetized inhomogeneous matter is blown away.

  15. Spectral evolution of active galactic nuclei: A unified description of the X-ray and gamma-ray backgrounds

    International Nuclear Information System (INIS)

    Letter, D.; Boldt, E.

    1982-01-01

    A model for spectral evolution is presented whereby active galactic nuclei (AGN) of the type observed individually have emerged from an earlier stage at zroughly-equal4 in which they are the thermal X-ray sources responsible for most of the comic X-ray background (CXB). We pursue the conjecture that these precursor objects are initially supermassive Schwarzschild black holes with accretion disks radiating near the Eddington luminosity limit. It is noted that after approx.10 8 years these central black holes are spun up to a ''canonical'' Kerr equilibriuim state (a/M = 0.998) and shown how they can lead to spectral evolution involving nonthermal emission extending to gamma-rays, at the expense of reduced thermal disk radiation. A superposition of sources in the precursor stage can thereby account for that major portion of the CXB remaining after the contributions of usual AGN are considered, while a superposition of AGN sources at z<1 can account for the gamima-ray background. Extensive X-ray measurements carried out with the HEAO 1 and HEAO 2 missions, as well as gamma-ray and optical data, are shown to compare favorably with principal features of this model. Several further observational tests are suggested for establishing the validity of this scenario for AGN spectral evolution

  16. THE DIFFERENCES IN THE TORUS GEOMETRY BETWEEN HIDDEN AND NON-HIDDEN BROAD LINE ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, Kohei; Ueda, Yoshihiro [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Packham, Christopher; Lopez-Rodriguez, Enrique; Alsip, Crystal D. [Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 (United States); Almeida, Cristina Ramos; Ramos, Andrés Asensio; González-Martín, Omaira [Instituto de Astrofísica de Canarias, C/Vía Láctea, s/n, E-38205 La Laguna, Tenerife (Spain); Alonso-Herrero, Almudena [Instituto de Física de Cantabria, CSIC-Universidad de Cantabria, E-39005 Santander (Spain); Díaz-Santos, Tanio [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Elitzur, Moshe [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055 (United States); Hönig, Sebastian F. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Imanishi, Masatoshi [Subaru Telescope, 650 North A’ohoku Place, Hilo, HI 96720 (United States); Levenson, Nancy A. [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Mason, Rachel E. [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, HI 96720 (United States); Perlman, Eric S., E-mail: ichikawa@kusastro.kyoto-u.ac.jp [Department of Physics and Space Sciences, 150 W. University Blvd., Florida Institute of Technology, Melbourne, FL 32901 (United States)

    2015-04-20

    We present results from the fitting of infrared (IR) spectral energy distributions of 21 active galactic nuclei (AGNs) with clumpy torus models. We compiled high spatial resolution (∼0.3–0.7 arcsec) mid-IR (MIR) N-band spectroscopy, Q-band imaging, and nuclear near- and MIR photometry from the literature. Combining these nuclear near- and MIR observations, far-IR photometry, and clumpy torus models enables us to put constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties: type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the torus model parameters gives us the first quantitative torus geometrical view for each subgroup. We find that NHBLR AGNs have smaller torus opening angles and larger covering factors than HBLR AGNs. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume given the small torus opening angle and (b) the increased torus obscuration between the observer and the scattering region. These effects give a reasonable explanation for the lack of observed HBLR in some type-2 AGNs.

  17. THE BLACK HOLE MASS-BULGE LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI FROM REVERBERATION MAPPING AND HUBBLE SPACE TELESCOPE IMAGING

    International Nuclear Information System (INIS)

    Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.; Vestergaard, Marianne

    2009-01-01

    We investigate the relationship between black hole mass and bulge luminosity for active galactic nuclei (AGNs) with reverberation-based black hole mass measurements and bulge luminosities from two-dimensional decompositions of Hubble Space Telescope host galaxy images. We find that the slope of the relationship for AGNs is 0.76-0.85 with an uncertainty of ∼0.1, somewhat shallower than the M BH ∝ L 1.0±0.1 relationship that has been fit to nearby quiescent galaxies with dynamical black hole mass measurements. This difference is somewhat perplexing, as the AGN black hole masses include an overall scaling factor that brings the AGN M BH -σ * relationship into agreement with that of quiescent galaxies. We discuss biases that may be inherent to the AGN and quiescent galaxy samples and could cause the apparent inconsistency in the forms of their M BH -L bulge relationships. Recent work by Graham, however, presents a similar slope of ∼0.8 for the quiescent galaxies and may bring the relationship for AGNs and quiescent galaxies into agreement.

  18. Galactic bulges

    CERN Document Server

    Peletier, Reynier; Gadotti, Dimitri

    2016-01-01

    This book consists of invited reviews on Galactic Bulges written by experts in the field. A central point of the book is that, while in the standard picture of galaxy formation a significant amount of the baryonic mass is expected to reside in classical bulges, the question what is the fraction of galaxies with no classical bulges in the local Universe has remained open. The most spectacular example of a galaxy with no significant classical bulge is the Milky Way. The reviews of this book attempt to clarify the role of the various types of bulges during the mass build-up of galaxies, based on morphology, kinematics, and stellar populations, and connecting their properties at low and high redshifts. The observed properties are compared with the predictions of the theoretical models, accounting for the many physical processes leading to the central mass concentration and their destruction in galaxies. This book serves as an entry point for PhD students and non-specialists and as a reference work for researchers...

  19. Tracking Solar Type II Bursts with Space Based Radio Interferometers

    Science.gov (United States)

    Hegedus, Alexander M.; Kasper, Justin C.; Manchester, Ward B.

    2018-06-01

    The Earth’s Ionosphere limits radio measurements on its surface, blocking out any radiation below 10 MHz. Valuable insight into many astrophysical processes could be gained by having a radio interferometer in space to image the low frequency window for the first time. One application is observing type II bursts tracking solar energetic particle acceleration in Coronal Mass Ejections (CMEs). In this work we create a simulated data processing pipeline for several space based radio interferometer (SBRI) concepts and evaluate their performance in the task of localizing these type II bursts.Traditional radio astronomy software is hard coded to assume an Earth based array. To circumvent this, we manually calculate the antenna separations and insert them along with the simulated visibilities into a CASA MS file for analysis. To create the realest possible virtual input data, we take a 2-temperature MHD simulation of a CME event, superimpose realistic radio emission models from the CME-driven shock front, and propagate the signal through simulated SBRIs. We consider both probabilistic emission models derived from plasma parameters correlated with type II bursts, and analytical emission models using plasma emission wave interaction theory.One proposed SBRI is the pathfinder mission SunRISE, a 6 CubeSat interferometer to circle the Earth in a GEO graveyard orbit. We test simulated trajectories of SunRISE and image what the array recovers, comparing it to the virtual input. An interferometer on the lunar surface would be a stable alternative that avoids noise sources that affect orbiting arrays, namely the phase noise from positional uncertainty and atmospheric 10s-100s kHz noise. Using Digital Elevation Models from laser altimeter data, we test different sets of locations on the lunar surface to find near optimal configurations for tracking type II bursts far from the sun. Custom software is used to model the response of different array configurations over the lunar year

  20. The adaptor protein SAP regulates type II NKT-cell development, cytokine production, and cytotoxicity against lymphoma.

    Science.gov (United States)

    Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya; Cardell, Susanna L; Stein, Paul L; Wang, Chyung-Ru

    2014-12-01

    CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT-cell TCR transgenic mouse model, we demonstrated that CD1d-expressing hematopoietic cells, but not thymic epithelial cells, meditate efficient selection of type II NKT cells. Furthermore, we showed that SAP regulates type II NKT-cell development by controlling early growth response 2 protein and promyelocytic leukemia zinc finger expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IFN regulatory factor 4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Study of starburst galaxies and active galactic nuclei in the mid-infrared with the ISOCAM instrument

    International Nuclear Information System (INIS)

    Laurent, Olivier

    1999-01-01

    This thesis is dedicated to the study of starburst galaxies and active galactic nuclei (AGNs) in the mid-infrared between 3 and 16 μm with the ISOCAM instrument. The study of nearby prototypical galaxies such as NGC 1068 and M 82 lead me to decompose the emission into three components. The star forming regions are characterized by (1) the infrared bands at 6.2, 7.7, 8.6, 11.3 and 12.7 μm originating from the photo-dissociation regions and also by (2) a continuum at 15 μm produced by the very small grains in HII regions. I show that AGNs have (3) strong continuum with an important contribution between 3 and 10 μm arising from hot dust heated to high temperatures of the order of 1000 K. I present two diagnostic diagrams based on the spectral properties of the three components allowing me to distinguish AGNs from starburst regions. In interacting galaxies, I show that some extra-nuclear regions harboring starburst activity can dominate the emission at 15 μm as in the Cartwheel and the Antennae galaxies. Using mid-infrared spectral features, I also define two prototypes of ultra-luminous galaxies dominated either by starburst activity in the case of Arp 220 or by the AGN in the Super-Antennae galaxy (IRAS 19254-7245). I explain how this diagram and the selection criteria evolve according to redshift. Finally, I show how we can develop new diagnostics using filters of the IRAC instrument on board the next infrared space observatory SIRTF. (author) [fr

  2. Active Galactic Nuclei: the Shape of Material Around Black Holes and the Witch of Agnesi Function. Asymmetry of Neutrino Particle Density

    Directory of Open Access Journals (Sweden)

    Vezzoli G. C.

    2009-10-01

    Full Text Available A mathematical representation is given and physically described for the shape of the very hot material that immediately surrounds a black hole and the warm material located at a greater distance from the black hole, as related to active galactic nuclei. The shape of the material surrounding the black hole is interpreted in terms of asymmetry of the neutrino flux. Detailed experimental measurements on radioactive decay influenced by astrophysical events are given to support this interpretation.

  3. A Test of the Formation Mechanism of the Broad Line Region in Active Galactic Nuclei

    Czech Academy of Sciences Publication Activity Database

    Czerny, B.; Du, P.; Wang, J.-M.; Karas, Vladimír

    2016-01-01

    Roč. 832, č. 1 (2016), 15/1-15/11 ISSN 0004-637X Institutional support: RVO:67985815 Keywords : galaxies * emission lines * active galaxies Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.533, year: 2016

  4. Radio Wavelength Studies of the Galactic Center Source N3, Spectroscopic Instrumentation For Robotic Telescope Systems, and Developing Active Learning Activities for Astronomy Laboratory Courses

    Science.gov (United States)

    Ludovici, Dominic Alesio

    2017-08-01

    The mysterious radio source N3 appears to be located within the vicinity of the Radio Arc region of the Galactic Center. To investigate the nature of this source, we have conducted radio observations with the VLA and the VLBA. Continuum observations between 2 and 50 GHz reveal that N3 is an extremely compact and bright source with a non-thermal spectrum. Molecular line observations with the VLA reveal a compact molecular cloud adjacent to N3 in projection. The properties of this cloud are consistent with other galactic center clouds. We are able to rule out several hypotheses for the nature of N3, though a micro-blazar origin cannot be ruled out. Robotic Telescope systems are now seeing widespread deployment as both teaching and research instruments. While these systems have traditionally been able to produce high quality images, these systems have lacked the capability to conduct spectroscopic observations. To enable spectroscopic observations on the Iowa Robotic Observatory, we have developed a low cost (˜ 500), low resolution (R ˜ 300) spectrometer which mounts inside a modified filter wheel and a moderate cost (˜ 5000), medium resolution (R ˜ 8000) fiber-fed spectrometer. Software has been developed to operate both instruments robotically and calibration pipelines are being developed to automate calibration of the data. The University of Iowa offers several introductory astronomy laboratory courses taken by many hundreds of students each semester. To improve student learning in these laboratory courses, we have worked to integrate active learning into laboratory activities. We present the pedagogical approaches used to develop and update the laboratory activities and present an inventory of the current laboratory exercises. Using the inventory, we make observations of the strengths and weaknesses of the current exercises and provide suggestions for future refinement of the astronomy laboratory curriculum.

  5. THE BLUESHIFTING AND BALDWIN EFFECTS FOR THE [O III] λ5007 EMISSION LINE IN TYPE 1 ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Zhang Kai; Dong Xiaobo; Wang Tinggui; Gaskell, C. Martin

    2011-01-01

    We use homogeneous samples of radio-quiet Seyfert 1 galaxies and QSOs selected from the Sloan Digital Sky Survey to investigate the connection between the velocity shift and the equivalent width (EW) of the [O III] λ5007 emission line, and their correlations with physical parameters of active galactic nuclei (AGNs). We find a significant and negative correlation between the EW of the core component, EW(core), and the blueshift of either the core (the peak), the wing, or the total profile of [O III] emission; it is fairly strong for the blueshift of the total profile in particular. However, both quantities (EW and velocity shift) generally have only weak, if any, correlations with fundamental AGN parameters such as the nuclear continuum luminosity at 5100 A ( 5100 ), black hole mass (M BH ), and the Eddington ratio (L/L Edd ); these correlations include the classical Baldwin effect of EW(core), an inverse Baldwin effect of EW(wing), and the relationship between velocity shifts and L/L Edd . Our findings suggest that both the large object-to-object variation in the strength of [O III] emission and the blueshift-EW(core) connection are not governed primarily by fundamental AGN parameters such as L 5100 , M BH , and L/L Edd . We propose that the interstellar medium conditions of the host galaxies play a major role instead in the diversity of the [O III] properties in active galaxies. This suggests that the use of [O III] λ5007 luminosity as a proxy of AGN luminosity does not depend strongly on the above-mentioned fundamental AGN parameters.

  6. The effects of baryon physics, black holes and active galactic nucleus feedback on the mass distribution in clusters of galaxies

    Science.gov (United States)

    Martizzi, Davide; Teyssier, Romain; Moore, Ben; Wentz, Tina

    2012-06-01

    The spatial distribution of matter in clusters of galaxies is mainly determined by the dominant dark matter component; however, physical processes involving baryonic matter are able to modify it significantly. We analyse a set of 500 pc resolution cosmological simulations of a cluster of galaxies with mass comparable to Virgo, performed with the AMR code RAMSES. We compare the mass density profiles of the dark, stellar and gaseous matter components of the cluster that result from different assumptions for the subgrid baryonic physics and galaxy formation processes. First, the prediction of a gravity-only N-body simulation is compared to that of a hydrodynamical simulation with standard galaxy formation recipes, and then all results are compared to a hydrodynamical simulation which includes thermal active galactic nucleus (AGN) feedback from supermassive black holes (SMBHs). We find the usual effects of overcooling and adiabatic contraction in the run with standard galaxy formation physics, but very different results are found when implementing SMBHs and AGN feedback. Star formation is strongly quenched, producing lower stellar densities throughout the cluster, and much less cold gas is available for star formation at low redshifts. At redshift z= 0 we find a flat density core of radius 10 kpc in both the dark and stellar matter density profiles. We speculate on the possible formation mechanisms able to produce such cores and we conclude that they can be produced through the coupling of different processes: (I) dynamical friction from the decay of black hole orbits during galaxy mergers; (II) AGN-driven gas outflows producing fluctuations of the gravitational potential causing the removal of collisionless matter from the central region of the cluster; (III) adiabatic expansion in response to the slow expulsion of gas from the central region of the cluster during the quiescent mode of AGN activity.

  7. A Long Decay of X-Ray Flux and Spectral Evolution in the Supersoft Active Galactic Nucleus GSN 069

    Science.gov (United States)

    Shu, X. W.; Wang, S. S.; Dou, L. M.; Jiang, N.; Wang, J. X.; Wang, T. G.

    2018-04-01

    GSN 069 is an optically identified very low-mass active galactic nuclei (AGN) that shows supersoft X-ray emission. The source is known to exhibit a huge X-ray outburst, with flux increased by more than a factor of ∼240 compared to the quiescence state. We report its long-term evolution in the X-ray flux and spectral variations over a timescale of ∼decade, using both new and archival X-ray observations from the XMM-Newton and Swift. The new Swift observations detected the source in its lowest level of X-ray activity since the outburst, a factor of ∼4 lower in the 0.2–2 keV flux than that obtained with the XMM-Newton observations nearly eight years ago. Combining with the historical X-ray measurements, we find that the X-ray flux is decreasing slowly. There seemed to be spectral softening associated with the drop of X-ray flux. In addition, we find evidence for the presence of a weak, variable, hard X-ray component, in addition to the dominant thermal blackbody emission reported before. The long decay of X-ray flux and spectral evolution, as well as the supersoft X-ray spectra, suggest that the source could be a tidal disruption event (TDE), though a highly variable AGN cannot be fully ruled out. Further continued X-ray monitoring would be required to test the TDE interpretation, by better determining the flux evolution in the decay phase.

  8. Polyclonal type II natural killer T cells require PLZF and SAP for their development and contribute to CpG-mediated antitumor response

    Science.gov (United States)

    Zhao, Jie; Weng, Xiufang; Bagchi, Sreya; Wang, Chyung-Ru

    2014-01-01

    CD1d-restricted natural killer T (NKT) cells are innate-like T cells with potent immunomodulatory function via rapid production of both Th1 and Th2 cytokines. NKT cells comprise well-characterized type I NKT cells, which can be detected by α-galactosylceramide-loaded CD1d tetramers, and less-studied type II NKT cells, which do not recognize α-galactosylceramide. Here we characterized type II NKT cells on a polyclonal level by using a Jα18-deficient IL-4 reporter mouse model. This model allows us to track type II NTK cells by the GFP+TCRβ+ phenotype in the thymus and liver. We found type II NKT cells, like type I NKT cells, exhibit an activated phenotype and are dependent on the transcriptional regulator promyelocytic leukemia zinc finger (PLZF) and the adaptor molecule signaling lymphocyte activation molecule-associated protein (SAP) for their development. Type II NKT cells are potently activated by β-D-glucopyranosylceramide (β-GlcCer) but not sulfatide or phospholipids in a CD1d-dependent manner, with the stimulatory capacity of β-GlcCer influenced by acyl chain length. Compared with type I NKT cells, type II NKT cells produce lower levels of IFN-γ but comparable amounts of IL-13 in response to polyclonal T-cell receptor stimulation, suggesting they may play different roles in regulating immune responses. Furthermore, type II NKT cells can be activated by CpG oligodeoxynucletides to produce IFN-γ, but not IL-4 or IL-13. Importantly, CpG-activated type II NKT cells contribute to the antitumor effect of CpG in the B16 melanoma model. Taken together, our data reveal the characteristics of polyclonal type II NKT cells and their potential role in antitumor immunotherapy. PMID:24550295

  9. Predicted continuum spectra of type II supernovae - LTE results

    Science.gov (United States)

    Shaviv, G.; Wehrse, R.; Wagoner, R. V.

    1985-01-01

    The continuum spectral energy distribution of the flux emerging from type II supernovae is calculated from quasi-static radiative transfer through a power-law density gradient, assuming radiative equilibrium and LTE. It is found that the Balmer jump disappears at high effective temperatures and low densities, while the spectrum resembles that of a dilute blackbody but is flatter with a sharper cutoff at the short-wavelength end. A significant UV excess is found in all models calculated. The calculation should be considered exploratory because of significant effects which are anticipated to arise from departure from LTE.

  10. Type II Superstring Field Theory: Geometric Approach and Operadic Description

    CERN Document Server

    Jurco, Branislav

    2013-01-01

    We outline the construction of type II superstring field theory leading to a geometric and algebraic BV master equation, analogous to Zwiebach's construction for the bosonic string. The construction uses the small Hilbert space. Elementary vertices of the non-polynomial action are described with the help of a properly formulated minimal area problem. They give rise to an infinite tower of superstring field products defining a $\\mathcal{N}=1$ generalization of a loop homotopy Lie algebra, the genus zero part generalizing a homotopy Lie algebra. Finally, we give an operadic interpretation of the construction.

  11. Vitamin D - Dependent Rickets, Type II Case Report

    OpenAIRE

    Azemi, Mehmedali; Berisha, Majlinda; Ismaili-Jaha, Vlora; Kolgeci, Selim; Hoxha, Rina; Grajçevci-Uka, Violeta; Hoxha-Kamberi, Teuta

    2014-01-01

    Aim: The aim of this work the report of one case with vitamin D-dependent rickets, type II. Methods: Diagnosis has been established based on anamnesis, physical examination, laboratory findings and radiological examination. Results: A female child (age 25 months) has been hospitalized due to bone deformity, bone pain, alopecia and walking difficulties. The laboratory findings have revealed that the calcium values was low (1.20 mmol/L), phosphates in the reference value (1.30 mmol/L) the alkal...

  12. Achalasia in a Patient with Polyglandular Autoimmune Syndrome Type II

    Directory of Open Access Journals (Sweden)

    Bashar S. Amr

    2015-05-01

    Full Text Available Achalasia is a rare disease characterized by aperistalsis of the esophageal body and failure of the lower esophageal sphincter to relax. The etiology of this disease remains unknown. Polyglandular autoimmune syndrome type II is a well-identified disease characterized by the occurrence of autoimmune Addison's disease in combination with autoimmune thyroid disease and/or type 1 diabetes mellitus. We report a case that suggests autoimmunity and immunogenicity as a probable contributing factor for association of these two rare disorders.

  13. Flux line lattice in type II super conductors

    International Nuclear Information System (INIS)

    Manindra Kumar; Singh, Arun Kumar; Surendra Kumar

    2003-01-01

    The shear modules C 66 of the flux line lattice in type II super conductors can be obtained from a two body interaction between the flux lines even at large inductions B ∼ HC 2 . The potential is composed of a repulsive and an attractive part and has a range diverging at HC 2 . An explicit expression for the Ginzberg-Landau C 66 is given for arbitrary B and k' (G-L parameter). The graph for C 66 exhibits the expected maximum at a certain value of b. (author)

  14. Interaction of ultrasound with vortices in type-II superconductors

    International Nuclear Information System (INIS)

    Sonin, E.B.

    1996-01-01

    The theory of ultrasound in the mixed state of type-II superconductors is suggested which takes into account the Magnus force on vortices, the anti-Magnus force on ions, and diamagnetism of the mixed state. The acoustic Faraday effect (rotation of polarization of the transverse ultrasonic wave propagating along vortices) is linear in the Magnus force in any regime of the flux flow for wavelengths now used in the ultrasound experiments. Therefore, in contrast to previous predictions, the Faraday effect should be looked for only in clean superconductors with a strong Magnus force. copyright 1996 The American Physical Society

  15. Levitation of a magnet over a flat type II superconductor

    International Nuclear Information System (INIS)

    Hellman, F.; Gyorgy, E.M.; Johnson, D.W. Jr.; O'Bryan, H.M.; Sherwood, R.C.

    1988-01-01

    Levitation of a magnet over a type II superconductor where the field at the superconductor exceeds H/sub c/ 1 is described and shown. The penetration and pinning of the flux lines in the superconductor cause the position of the magnet to be stable over a flat disk; a complete Meissner effect would make this position unstable. Furthermore, the observed dependence of the height of levitation on such variables as the thickness of the superconducting disk and the size of the magnet are consistent with a model described in this paper based on the energy cost of flux penetration through vortices and inconsistent with a Meissner effect model

  16. Repopulation of denuded tracheal grafts with alveolar type II cells

    International Nuclear Information System (INIS)

    Johnson, N.F.

    1988-01-01

    Repopulation of denuded heterotopic tracheal grafts with populations of specific epithelial cell types is one approach to study the differentiation potential of various cell types. This technique has been adopted to delineate the differentiation pathways of alveolar type II cells isolated from rat lungs. Under the conditions of this experiment, the reestablished epithelial lining was alveolar-like, however, ultrastructural analysis of the cells showed them to be like Clara cells. These preliminary results suggest that the secretary cells of the lung parenchyma and terminal airways may share a common ancestry. (author)

  17. Type II restriction endonucleases : a historical perspective and more

    OpenAIRE

    Pingoud, Alfred; Wilson, Geoffrey G.; Wende, Wolfgang

    2014-01-01

    This article continues the series of Surveys and Summaries on restriction endonucleases (REases) begun this year in Nucleic Acids Research. Here we discuss ‘Type II’ REases, the kind used for DNA analysis and cloning. We focus on their biochemistry: what they are, what they do, and how they do it. Type II REases are produced by prokaryotes to combat bacteriophages. With extreme accuracy, each recognizes a particular sequence in double-stranded DNA and cleaves at a fixed position within or nea...

  18. The Host Galaxy and Central Engine of the Dwarf Active Galactic Nucleus POX 52

    Science.gov (United States)

    Thornton, Carol E.; Barth, Aaron J.; Ho, Luis C.; Rutledge, Robert E.; Greene, Jenny E.

    2008-10-01

    We present new multiwavelength observations of the dwarf Seyfert 1 galaxy POX 52 in order to investigate the properties of the host galaxy and the active nucleus and to examine the mass of its black hole, previously estimated to be ~105 M⊙. HST ACS HRC images show that the host galaxy has a dwarf elliptical morphology (MI = - 18.4 mag, Sérsic index n = 4.3) with no detected disk component or spiral structure, confirming previous results from ground-based imaging. X-ray observations from both Chandra and XMM-Newton show strong (factor of 2) variability over timescales as short as 500 s, as well as a dramatic decrease in the absorbing column density over a 9 month period. We attribute this change to a partial covering absorber, with a 94% covering fraction and NH = 58+ 8.4-9.2 × 1021 cm -2, that moved out of the line of sight in between the XMM-Newton and Chandra observations. Combining these data with observations from the VLA, Spitzer, and archival data from 2MASS and GALEX, we examine the SED of the active nucleus. Its shape is broadly similar to typical radio-quiet quasar SEDs, despite the very low bolometric luminosity of Lbol = 1.3 × 1043 ergs s-1. Finally, we compare black hole mass estimators, including methods based on X-ray variability, and optical scaling relations using the broad Hβ line width and AGN continuum luminosity, finding a range of black hole mass from all methods to be MBH = (2.2-4.2) × 105 M⊙, with an Eddington ratio of Lbol/LEdd ≈ 0.2-0.5.

  19. Alteration of Sequence Specificity of the Type IIS Restriction Endonuclease BtsI

    OpenAIRE

    Guan, Shengxi; Blanchard, Aine; Zhang, Penghua; Zhu, Zhenyu

    2010-01-01

    The Type IIS restriction endonuclease BtsI recognizes and digests at GCAGTG(2/0). It comprises two subunits: BtsIA and BtsIB. The BtsIB subunit contains the recognition domain, one catalytic domain for bottom strand nicking and part of the catalytic domain for the top strand nicking. BtsIA has the rest of the catalytic domain that is responsible for the DNA top strand nicking. BtsIA alone has no activity unless it mixes with BtsIB to reconstitute the BtsI activity. During characterization of ...

  20. ON THE X-RAY BALDWIN EFFECT IN ACTIVE GALACTIC NUCLEI OBSERVED BY THE CHANDRA HIGH-ENERGY GRATING

    International Nuclear Information System (INIS)

    Shu, X. W.; Wang, J. X.; Jiang, P.; Zhou, Y. Y.; Yaqoob, T.

    2012-01-01

    Using Chandra high-energy grating (HEG) observations of 32 active galactic nuclei (AGNs), we present a systematic study of the X-ray Baldwin effect (XBE; i.e., the anti-correlation between the narrow Fe Kα line equivalent width (EW) and X-ray continuum luminosity for AGN samples) with the highest spectral resolution currently available. We have previously reported an anti-correlation with EW∝L –0.22 2-10keV in an HEG sample, and the correlation is much weaker after averaging multiple observations of individual AGNs (EW∝L –0.13 2-10keV ). This indicates that rapid variation in the X-ray continuum plays an important role in producing the XBE, and such an effect should also be visible in individual AGNs. In this Letter, by normalizing the line EWs and continuum luminosities to the time-averaged values for each AGN in our sample with multiple HEG observations, we find a strong anti-correlation between EW and L X (EW/(EW)∝(L/(L)) –0.82±0.10 ), consistent with the XBE expected in an individual AGN if the narrow line flux remains constant while the continuum varies. This is first observational evidence that the Fe Kα line flux in a large sample of AGNs lacks a corresponding response to the continuum variation, supporting the fact that the narrow Fe-K line emission originates from a region far from the nucleus. We then performed Monte Carlo simulations to address whether the global XBE can be produced by X-ray continuum variation solely, and found that such an interpretation of the XBE cannot be ruled out statistically. One should thus be very cautious before drawing any scientific conclusion based on an observed XBE.

  1. The 60 Month All-Sky Burst Alert Telescope Survey of Active Galactic Nucleus and the Anisotropy of Nearby AGNs

    Science.gov (United States)

    Ajello, M.; Alexander, D. M.; Greiner, J.; Madejeski, G. M.; Gehrels, N.; Burlon, D.

    2014-01-01

    Surveys above 10 keV represent one of the best resources to provide an unbiased census of the population of active galactic nuclei (AGNs). We present the results of 60 months of observation of the hard X-ray sky with Swift/Burst Alert Telescope (BAT). In this time frame, BAT-detected (in the 15-55 keV band) 720 sources in an all-sky survey of which 428 are associated with AGNs, most of which are nearby. Our sample has negligible incompleteness and statistics a factor of approx. 2 larger over similarly complete sets of AGNs. Our sample contains (at least) 15 bona fide Compton-thick AGNs and 3 likely candidates. Compton-thick AGNs represent approx. 5% of AGN samples detected above 15 keV. We use the BAT data set to refine the determination of the log N-log S of AGNs which is extremely important, now that NuSTAR prepares for launch, toward assessing the AGN contribution to the cosmic X-ray background. We show that the log N-log S of AGNs selected above 10 keV is now established to approx. 10% precision. We derive the luminosity function of Compton-thick AGNs and measure a space density of 7.9(+4.1/-2.9)× 10(exp -5)/cubic Mpc for objects with a de-absorbed luminosity larger than 2 × 10(exp 42) erg / s. As the BAT AGNs are all mostly local, they allow us to investigate the spatial distribution of AGNs in the nearby universe regardless of absorption. We find concentrations of AGNs that coincide spatially with the largest congregations of matter in the local (much < 85 Mpc) universe. There is some evidence that the fraction of Seyfert 2 objects is larger than average in the direction of these dense regions..

  2. Spatially resolved spectra of the 'teacup' active galactic nucleus: tracing the history of a dying quasar

    International Nuclear Information System (INIS)

    Gagne, J. P.; Crenshaw, D. M.; Fischer, T. C.; Kraemer, S. B.; Schmitt, H. R.; Keel, W. C.; Rafter, S.; Bennert, V. N.; Schawinski, K.

    2014-01-01

    The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing extended emission-line regions (EELRs), the most famous being Hanny's Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup active galactic nucleus (AGN). Nicknamed for its EELR, which has a 'handle'-like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze the physical conditions of this galaxy with long-slit, ground-based spectroscopy from the Lowell, Lick, and KPNO observatories. With the Lowell 1.8 m Perkin's telescope we took multiple observations at different offset positions, allowing us to recover spatially resolved spectra across the galaxy. Line diagnostics indicate the ionized gas is photoionized primarily by the AGN. Additionally we are able to derive the hydrogen density from the [S II] λ6716/λ6731 ratio. We generated two-component photoionization models for each spatially resolved Lowell spectrum. These models allow us to calculate the AGN bolometric luminosity seen by the gas at different radii from the nuclear center of the Teacup. Our results show a drop in bolometric luminosity by more than two orders of magnitude from the EELR to the nucleus, suggesting that the AGN has decreased in luminosity by this amount in a continuous fashion over 46,000 yr, supporting the case for a dying AGN in this galaxy independent of any IR based evidence. We demonstrate that spatially resolved photoionization modeling could be applied to EELRs to investigate long timescale variability.

  3. Spatially resolved spectra of the 'teacup' active galactic nucleus: tracing the history of a dying quasar

    Energy Technology Data Exchange (ETDEWEB)

    Gagne, J. P.; Crenshaw, D. M.; Fischer, T. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, 25 Park Place South SE, Suite 600, Atlanta, GA 30303 (United States); Kraemer, S. B. [Department of Physics, Catholic University of America, 620 Michigan Avenue, N.E., Washington, DC 20064 (United States); Schmitt, H. R. [Naval Research Laboratory, Washington, DC 20375 (United States); Keel, W. C. [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487 (United States); Rafter, S. [Physics Department, Technion, Haifa 32000 (Israel); Bennert, V. N. [Physics Department, California Polytechnic State University San Luis Obispo, CA 93407 (United States); Schawinski, K., E-mail: gagne@chara.gsu.edu [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland)

    2014-09-01

    The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing extended emission-line regions (EELRs), the most famous being Hanny's Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup active galactic nucleus (AGN). Nicknamed for its EELR, which has a 'handle'-like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze the physical conditions of this galaxy with long-slit, ground-based spectroscopy from the Lowell, Lick, and KPNO observatories. With the Lowell 1.8 m Perkin's telescope we took multiple observations at different offset positions, allowing us to recover spatially resolved spectra across the galaxy. Line diagnostics indicate the ionized gas is photoionized primarily by the AGN. Additionally we are able to derive the hydrogen density from the [S II] λ6716/λ6731 ratio. We generated two-component photoionization models for each spatially resolved Lowell spectrum. These models allow us to calculate the AGN bolometric luminosity seen by the gas at different radii from the nuclear center of the Teacup. Our results show a drop in bolometric luminosity by more than two orders of magnitude from the EELR to the nucleus, suggesting that the AGN has decreased in luminosity by this amount in a continuous fashion over 46,000 yr, supporting the case for a dying AGN in this galaxy independent of any IR based evidence. We demonstrate that spatially resolved photoionization modeling could be applied to EELRs to investigate long timescale variability.

  4. New Spectral Model for Constraining Torus Covering Factors from Broadband X-Ray Spectra of Active Galactic Nuclei

    Science.gov (United States)

    Baloković, M.; Brightman, M.; Harrison, F. A.; Comastri, A.; Ricci, C.; Buchner, J.; Gandhi, P.; Farrah, D.; Stern, D.

    2018-02-01

    The basic unified model of active galactic nuclei (AGNs) invokes an anisotropic obscuring structure, usually referred to as a torus, to explain AGN obscuration as an angle-dependent effect. We present a new grid of X-ray spectral templates based on radiative transfer calculations in neutral gas in an approximately toroidal geometry, appropriate for CCD-resolution X-ray spectra (FWHM ≥ 130 eV). Fitting the templates to broadband X-ray spectra of AGNs provides constraints on two important geometrical parameters of the gas distribution around the supermassive black hole: the average column density and the covering factor. Compared to the currently available spectral templates, our model is more flexible, and capable of providing constraints on the main torus parameters in a wider range of AGNs. We demonstrate the application of this model using hard X-ray spectra from NuSTAR (3–79 keV) for four AGNs covering a variety of classifications: 3C 390.3, NGC 2110, IC 5063, and NGC 7582. This small set of examples was chosen to illustrate the range of possible torus configurations, from disk-like to sphere-like geometries with column densities below, as well as above, the Compton-thick threshold. This diversity of torus properties challenges the simple assumption of a standard geometrically and optically thick toroidal structure commonly invoked in the basic form of the unified model of AGNs. Finding broad consistency between our constraints and those from infrared modeling, we discuss how the approach from the X-ray band complements similar measurements of AGN structures at other wavelengths.

  5. The active galactic nucleus population in X-ray-selected galaxy groups at 0.5 < Z < 1.1

    International Nuclear Information System (INIS)

    Oh, Semyeong; Woo, Jong-Hak; Matsuoka, Kenta; Mulchaey, John S.; Finoguenov, Alexis; Tanaka, Masayuki; Cooper, Michael C.; Ziparo, Felicia; Bauer, Franz E.

    2014-01-01

    We use Chandra data to study the incidence and properties of active galactic nuclei (AGNs) in 16 intermediate redshift (0.5 < z < 1.1) X-ray-selected galaxy groups in the Chandra Deep Field-South. We measure an AGN fraction of f(L X,H >10 42 ;M R <−20)=8.0 −2.3 +3.0 % at z-bar ∼0.74, approximately a factor of two higher than the AGN fraction found for rich clusters at comparable redshift. This extends the trend found at low redshift for groups to have higher AGN fractions than clusters. Our estimate of the AGN fraction is also more than a factor of three higher than that of low redshift X-ray-selected groups. Using optical spectra from various surveys, we also constrain the properties of emission-line selected AGNs in these groups. In contrast to the large population of X-ray AGNs (N(L X, H > 10 41 erg s –1 ) = 25), we find only four emission-line AGNs, three of which are also X-ray bright. Furthermore, most of the X-ray AGNs in our groups are optically dull (i.e., lack strong emission-lines), similar to those found in low redshift X-ray groups and clusters of galaxies. This contrasts with the AGN population found in low redshift optically selected groups which are dominated by emission-line AGNs. The differences between the optically and X-ray-selected AGNs populations in groups are consistent with a scenario where most AGNs in the densest environments are currently in a low accretion state.

  6. RESOLVING THE ACTIVE GALACTIC NUCLEUS AND HOST EMISSION IN THE MID-INFRARED USING A MODEL-INDEPENDENT SPECTRAL DECOMPOSITION

    Energy Technology Data Exchange (ETDEWEB)

    Hernán-Caballero, Antonio; Alonso-Herrero, Almudena [Instituto de Física de Cantabria, CSIC-UC, Avenida de los Castros s/n, E-39005, Santander (Spain); Hatziminaoglou, Evanthia [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Spoon, Henrik W. W. [Cornell University, CRSR, Space Sciences Building, Ithaca, NY 14853 (United States); Almeida, Cristina Ramos [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Santos, Tanio Díaz [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Hönig, Sebastian F. [School of Physics and Astronomy, University of Southampton, Southampton SO18 1BJ (United Kingdom); González-Martín, Omaira [Centro de Radioastronomía y Astrofísica (CRyA-UNAM), 3-72 (Xangari), 8701, Morelia (Mexico); Esquej, Pilar, E-mail: ahernan@ifca.unican.es [Departamento de Astrofísica, Facultad de CC. Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2015-04-20

    We present results on the spectral decomposition of 118 Spitzer Infrared Spectrograph (IRS) spectra from local active galactic nuclei (AGNs) using a large set of Spitzer/IRS spectra as templates. The templates are themselves IRS spectra from extreme cases where a single physical component (stellar, interstellar, or AGN) completely dominates the integrated mid-infrared emission. We show that a linear combination of one template for each physical component reproduces the observed IRS spectra of AGN hosts with unprecedented fidelity for a template fitting method with no need to model extinction separately. We use full probability distribution functions to estimate expectation values and uncertainties for observables, and find that the decomposition results are robust against degeneracies. Furthermore, we compare the AGN spectra derived from the spectral decomposition with sub-arcsecond resolution nuclear photometry and spectroscopy from ground-based observations. We find that the AGN component derived from the decomposition closely matches the nuclear spectrum with a 1σ dispersion of 0.12 dex in luminosity and typical uncertainties of ∼0.19 in the spectral index and ∼0.1 in the silicate strength. We conclude that the emission from the host galaxy can be reliably removed from the IRS spectra of AGNs. This allows for unbiased studies of the AGN emission in intermediate- and high-redshift galaxies—currently inaccesible to ground-based observations—with archival Spitzer/IRS data and in the future with the Mid-InfraRed Instrument of the James Webb Space Telescope. The decomposition code and templates are available at http://denebola.org/ahc/deblendIRS.

  7. The [O III] Profiles of Infrared-selected Active Galactic Nuclei: More Powerful Outflows in the Obscured Population

    Science.gov (United States)

    DiPompeo, M. A.; Hickox, R. C.; Carroll, C. M.; Runnoe, J. C.; Mullaney, J. R.; Fischer, T. C.

    2018-03-01

    We explore the kinematics of ionized gas via the [O III] λ5007 emission lines in active galactic nuclei (AGNs) selected on the basis of their mid-infrared (IR) emission, and split into obscured and unobscured populations based on their optical‑IR colors. After correcting for differences in redshift distributions, we provide composite spectra of spectroscopically and photometrically defined obscured/Type 2 and unobscured/Type 1 AGNs from 3500 to 7000 Å. The IR-selected obscured sources contain a mixture of narrow-lined Type 2 AGNs and intermediate sources that have broad Hα emission and significantly narrower Hβ. Using both [O III] luminosities and AGN luminosities derived from optical‑IR spectral energy distribution fitting, we find evidence for enhanced large-scale obscuration in the obscured sources. In matched bins of luminosity we find that the obscured population typically has broader, more blueshifted [O III] emission than in the unobscured sample, suggestive of more powerful AGN-driven outflows. This trend is not seen in spectroscopically classified samples, and is unlikely to be entirely explained by orientation effects. In addition, outflow velocities increase from small to moderate AGN E(B ‑ V) values, before flattening out (as traced by FWHM) and even decreasing (as traced by blueshift). While difficult to fully interpret in a single physical model, due to both the averaging over populations and the spatially averaged spectra, these results agree with previous findings that simple geometric unification models are insufficient for the IR-selected AGN population, and may fit into an evolutionary model for obscured and unobscured AGNs.

  8. Supermassive black holes with high accretion rates in active galactic nuclei. I. First results from a new reverberation mapping campaign

    International Nuclear Information System (INIS)

    Du, Pu; Hu, Chen; Qiu, Jie; Li, Yan-Rong; Wang, Jian-Min; Lu, Kai-Xing; Wang, Fang; Bai, Jin-Ming; Kaspi, Shai; Netzer, Hagai

    2014-01-01

    We report first results from a large project to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). Such objects may be different from other AGNs in being powered by slim accretion disks and showing saturated accretion luminosities, but both are not yet fully understood. The results are part of a large reverberation mapping (RM) campaign using the 2.4 m Shangri-La telescope at the Yunnan Observatory in China. The goals are to investigate the gas distribution near the BH and the properties of the central accretion disks, to measure BH mass and Eddington ratios, and to test the feasibility of using such objects as a new type of cosmological candles. The paper presents results for three objects, Mrk 335, Mrk 142, and IRAS F12397+3333, with Hβ time lags relative to the 5100 Å continuum of 10.6 −2.9 +1.7 , 6.4 −2.2 +0.8 and 11.4 −1.9 +2.9 days, respectively. The corresponding BH masses are (8.3 −3.2 +2.6 )×10 6 M ⊙ , (3.4 −1.2 +0.5 )×10 6 M ⊙ , and (7.5 −4.1 +4.3 )×10 6 M ⊙ , and the lower limits on the Eddington ratios are 0.6, 2.3, and 4.6 for the minimal radiative efficiency of 0.038. Mrk 142 and IRAS F12397+333 (extinction corrected) clearly deviate from the currently known relation between Hβ lag and continuum luminosity. The three Eddington ratios are beyond the values expected in thin accretion disks and two of them are the largest measured so far among objects with RM-based BH masses. We briefly discuss implications for slim disks, BH growth, and cosmology.

  9. Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. I. First Results from a New Reverberation Mapping Campaign

    Science.gov (United States)

    Du, Pu; Hu, Chen; Lu, Kai-Xing; Wang, Fang; Qiu, Jie; Li, Yan-Rong; Bai, Jin-Ming; Kaspi, Shai; Netzer, Hagai; Wang, Jian-Min; SEAMBH Collaboration

    2014-02-01

    We report first results from a large project to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). Such objects may be different from other AGNs in being powered by slim accretion disks and showing saturated accretion luminosities, but both are not yet fully understood. The results are part of a large reverberation mapping (RM) campaign using the 2.4 m Shangri-La telescope at the Yunnan Observatory in China. The goals are to investigate the gas distribution near the BH and the properties of the central accretion disks, to measure BH mass and Eddington ratios, and to test the feasibility of using such objects as a new type of cosmological candles. The paper presents results for three objects, Mrk 335, Mrk 142, and IRAS F12397+3333, with Hβ time lags relative to the 5100 Å continuum of 10.6^{+1.7}_{-2.9}, 6.4^{+0.8}_{-2.2} and 11.4^{+2.9}_{-1.9} days, respectively. The corresponding BH masses are (8.3_{-3.2}^{+2.6})\\times 10^6\\,M_{\\odot }, (3.4_{-1.2}^{+0.5})\\times 10^6\\,M_{\\odot }, and (7.5_{-4.1}^{+4.3})\\times 10^6\\,M_{\\odot }, and the lower limits on the Eddington ratios are 0.6, 2.3, and 4.6 for the minimal radiative efficiency of 0.038. Mrk 142 and IRAS F12397+333 (extinction corrected) clearly deviate from the currently known relation between Hβ lag and continuum luminosity. The three Eddington ratios are beyond the values expected in thin accretion disks and two of them are the largest measured so far among objects with RM-based BH masses. We briefly discuss implications for slim disks, BH growth, and cosmology.

  10. X-ray-bright optically faint active galactic nuclei in the Subaru Hyper Suprime-Cam wide survey

    Science.gov (United States)

    Terashima, Yuichi; Suganuma, Makoto; Akiyama, Masayuki; Greene, Jenny E.; Kawaguchi, Toshihiro; Iwasawa, Kazushi; Nagao, Tohru; Noda, Hirofumi; Toba, Yoshiki; Ueda, Yoshihiro; Yamashita, Takuji

    2018-01-01

    We construct a sample of X-ray-bright optically faint active galactic nuclei by combining Subaru Hyper Suprime-Cam, XMM-Newton, and infrared source catalogs. Fifty-three X-ray sources satisfying i-band magnitude fainter than 23.5 mag and X-ray counts with the EPIC-PN detector larger than 70 are selected from 9.1 deg2, and their spectral energy distributions (SEDs) and X-ray spectra are analyzed. Forty-four objects with an X-ray to i-band flux ratio FX/Fi > 10 are classified as extreme X-ray-to-optical flux sources. Spectral energy distributions of 48 among 53 are represented by templates of type 2 AGNs or star-forming galaxies and show the optical signature of stellar emission from host galaxies in the source rest frame. Infrared/optical SEDs indicate a significant contribution of emission from dust to the infrared fluxes, and that the central AGN is dust obscured. The photometric redshifts determined from the SEDs are in the range of 0.6-2.5. The X-ray spectra are fitted by an absorbed power-law model, and the intrinsic absorption column densities are modest (best-fit log NH = 20.5-23.5 cm-2 in most cases). The absorption-corrected X-ray luminosities are in the range of 6 × 1042-2 × 1045 erg s-1. Twenty objects are classified as type 2 quasars based on X-ray luminsosity and NH. The optical faintness is explained by a combination of redshifts (mostly z > 1.0), strong dust extinction, and in part a large ratio of dust/gas.

  11. A COMPTON-THICK ACTIVE GALACTIC NUCLEUS AT z ∼ 5 IN THE 4 Ms CHANDRA DEEP FIELD SOUTH

    International Nuclear Information System (INIS)

    Gilli, R.; Comastri, A.; Su, J.; Norman, C.; Vignali, C.; Tozzi, P.; Rosati, P.; Mainieri, V.; Stiavelli, M.; Brandt, W. N.; Xue, Y. Q.; Luo, B.; Castellano, M.; Fontana, A.; Fiore, F.; Ptak, A.

    2011-01-01

    We report the discovery of a Compton-thick active galactic nucleus (AGN) at z = 4.76 in the 4 Ms Chandra Deep Field South. This object was selected as a V-band dropout in HST/ACS images and previously recognized as an AGN from optical spectroscopy. The 4 Ms Chandra observations show a significant (∼4.2σ) X-ray detection at the V-band dropout position. The X-ray source displays a hardness ratio of HR = 0.23 ± 0.24, which, for a source at z ∼ 5, is highly suggestive of Compton-thick absorption. The source X-ray spectrum is seen above the background level in the energy range of ∼0.9-4 keV, i.e., in the rest-frame energy range of ∼5-23 keV. When fixing the photon index to Γ = 1.8, the measured column density is N H = 1.4 +0.9 -0.5 x 10 24 cm -2 , which is Compton thick. To our knowledge, this is the most distant heavily obscured AGN, confirmed by X-ray spectral analysis, discovered so far. The intrinsic (de-absorbed), rest-frame luminosity in the 2-10 keV band is ∼2.5 x 10 44 erg s -1 , which places this object among type-2 quasars. The spectral energy distribution shows that massive star formation is associated with obscured black hole (BH) accretion. This system may have then been caught during a major coeval episode of BH and stellar mass assembly at early times. The measure of the number density of heavily obscured AGN at high redshifts will be crucial to reconstructing the BH/galaxy evolution history from the beginning.

  12. Line-driven disk winds in active galactic nuclei: The critical importance of ionization and radiative transfer

    Energy Technology Data Exchange (ETDEWEB)

    Higginbottom, Nick; Knigge, Christian; Matthews, James H. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Proga, Daniel [Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154-4002 (United States); Long, Knox S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Sim, Stuart A., E-mail: nick_higginbottom@fastmail.fm [School of Mathematics and Physics, Queens University Belfast, University Road, Belfast, BT7 1NN (United Kingdom)

    2014-07-01

    Accretion disk winds are thought to produce many of the characteristic features seen in the spectra of active galactic nuclei (AGNs) and quasi-stellar objects (QSOs). These outflows also represent a natural form of feedback between the central supermassive black hole and its host galaxy. The mechanism for driving this mass loss remains unknown, although radiation pressure mediated by spectral lines is a leading candidate. Here, we calculate the ionization state of, and emergent spectra for, the hydrodynamic simulation of a line-driven disk wind previously presented by Proga and Kallman. To achieve this, we carry out a comprehensive Monte Carlo simulation of the radiative transfer through, and energy exchange within, the predicted outflow. We find that the wind is much more ionized than originally estimated. This is in part because it is much more difficult to shield any wind regions effectively when the outflow itself is allowed to reprocess and redirect ionizing photons. As a result, the calculated spectrum that would be observed from this particular outflow solution would not contain the ultraviolet spectral lines that are observed in many AGN/QSOs. Furthermore, the wind is so highly ionized that line driving would not actually be efficient. This does not necessarily mean that line-driven winds are not viable. However, our work does illustrate that in order to arrive at a self-consistent model of line-driven disk winds in AGN/QSO, it will be critical to include a more detailed treatment of radiative transfer and ionization in the next generation of hydrodynamic simulations.

  13. THE RADIO/GAMMA-RAY CONNECTION IN ACTIVE GALACTIC NUCLEI IN THE ERA OF THE FERMI LARGE AREA TELESCOPE

    International Nuclear Information System (INIS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Angelakis, E.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bonamente, E.; Bouvier, A.; Brigida, M.; Bruel, P.

    2011-01-01

    We present a detailed statistical analysis of the correlation between radio and gamma-ray emission of the active galactic nuclei (AGNs) detected by Fermi during its first year of operation, with the largest data sets ever used for this purpose. We use both archival interferometric 8.4 GHz data (from the Very Large Array and ATCA, for the full sample of 599 sources) and concurrent single-dish 15 GHz measurements from the Owens Valley Radio Observatory (OVRO, for a sub sample of 199 objects). Our unprecedentedly large sample permits us to assess with high accuracy the statistical significance of the correlation, using a surrogate data method designed to simultaneously account for common-distance bias and the effect of a limited dynamical range in the observed quantities. We find that the statistical significance of a positive correlation between the centimeter radio and the broadband (E > 100 MeV) gamma-ray energy flux is very high for the whole AGN sample, with a probability of -7 for the correlation appearing by chance. Using the OVRO data, we find that concurrent data improve the significance of the correlation from 1.6 x 10 -6 to 9.0 x 10 -8 . Our large sample size allows us to study the dependence of correlation strength and significance on specific source types and gamma-ray energy band. We find that the correlation is very significant (chance probability -7 ) for both flat spectrum radio quasars and BL Lac objects separately; a dependence of the correlation strength on the considered gamma-ray energy band is also present, but additional data will be necessary to constrain its significance.

  14. Can Winds Driven by Active Galactic Nuclei Account for the Extragalactic Gamma-Ray and Neutrino Backgrounds?

    Science.gov (United States)

    Liu, Ruo-Yu; Murase, Kohta; Inoue, Susumu; Ge, Chong; Wang, Xiang-Yu

    2018-05-01

    Various observations are revealing the widespread occurrence of fast and powerful winds in active galactic nuclei (AGNs) that are distinct from relativistic jets, likely launched from accretion disks and interacting strongly with the gas of their host galaxies. During the interaction, strong shocks are expected to form that can accelerate nonthermal particles to high energies. Such winds have been suggested to be responsible for a large fraction of the observed extragalactic gamma-ray background (EGB) and the diffuse neutrino background, via the decay of neutral and charged pions generated in inelastic pp collisions between protons accelerated by the forward shock and the ambient gas. However, previous studies did not properly account for processes such as adiabatic losses that may reduce the gamma-ray and neutrino fluxes significantly. We evaluate the production of gamma rays and neutrinos by AGN-driven winds in detail by modeling their hydrodynamic and thermal evolution, including the effects of their two-temperature structure. We find that they can only account for less than ∼30% of the EGB flux, as otherwise the model would violate the independent upper limit derived from the diffuse isotropic gamma-ray background. If the neutrino spectral index is steep with Γ ≳ 2.2, a severe tension with the isotropic gamma-ray background would arise as long as the winds contribute more than 20% of the IceCube neutrino flux in the 10–100 TeV range. At energies ≳ 100 TeV, we find that the IceCube neutrino flux may still be accountable by AGN-driven winds if the spectral index is as small as Γ ∼ 2.0–2.1.

  15. DRIVING OUTFLOWS WITH RELATIVISTIC JETS AND THE DEPENDENCE OF ACTIVE GALACTIC NUCLEUS FEEDBACK EFFICIENCY ON INTERSTELLAR MEDIUM INHOMOGENEITY

    International Nuclear Information System (INIS)

    Wagner, A. Y.; Umemura, M.; Bicknell, G. V.

    2012-01-01

    We examine the detailed physics of the feedback mechanism by relativistic active galactic nucleus (AGN) jets interacting with a two-phase fractal interstellar medium (ISM) in the kpc-scale core of galaxies using 29 three-dimensional grid-based hydrodynamical simulations. The feedback efficiency, as measured by the amount of cloud dispersal generated by the jet-ISM interactions, is sensitive to the maximum size of clouds in the fractal cloud distribution but not to their volume filling factor. Feedback ceases to be efficient for Eddington ratios P jet /L edd ∼ –4 , although systems with large cloud complexes ∼> 50 pc require jets of Eddington ratio in excess of 10 –2 to disperse the clouds appreciably. Based on measurements of the bubble expansion rates in our simulations, we argue that sub-grid AGN prescriptions resulting in negative feedback in cosmological simulations without a multi-phase treatment of the ISM are good approximations if the volume filling factor of warm-phase material is less than 0.1 and the cloud complexes are smaller than ∼25 pc. We find that the acceleration of the dense embedded clouds is provided by the ram pressure of the high-velocity flow through the porous channels of the warm phase, flow that has fully entrained the shocked hot-phase gas it has swept up, and is additionally mass loaded by ablated cloud material. This mechanism transfers 10% to 40% of the jet energy to the cold and warm gas, accelerating it within a few 10 to 100 Myr to velocities that match those observed in a range of high- and low-redshift radio galaxies hosting powerful radio jets.

  16. Time-dependent narrow emission-line profiles of quasars and active galactic nuclei

    International Nuclear Information System (INIS)

    Capriotti, E.R.; Foltz, C.B.

    1982-01-01

    The narrow-line emitting regions of quasars and active nuclei of galaxies are assumed to consist of material undergoing gravitational infall due to acceleration by centrally located mass concentrations. Two cases are considered. In one, the material is assumed to be in the form of optically thick, similar clouds which emit line radiation monochromatically, isotropically and in inverse proportion to the square of the distance from the center of the system. In the other case, the material is assumed to be homogeneous, isothermal and to have the same ionization structure everywhere. The material is assumed to be excited by an ionizing continuum created ty a supernova-like outburst of radiation. Line profiles are computed for various combinations of epoch after outburst, continuum decay times, and spectral resolution. The computed profiles are clearly asymmetric to the blue of the profile peak and for certain combinations of epoch and decay time, clearly asymmetric to the blue of line center. The computed profiles compare well with many observed [O III] profiles

  17. Gravitational Field Shielding by Scalar Field and Type II Superconductors

    Directory of Open Access Journals (Sweden)

    Zhang B. J.

    2013-01-01

    Full Text Available The gravitational field shielding by scalar field and type II superconductors are theoret- ically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polariza- tion of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low tempera- ture can be explained as the shielding of the Earth gravitational field by the Ginzburg- Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future.

  18. Albuminuria and associated risk factors in type II diabetics

    International Nuclear Information System (INIS)

    Hashim, R.; Ahmed, T.A.; Mushtaq, S.; Zafar, L.; Attique, M.; Khalil-ur-Rehman

    2004-01-01

    Objective: To determine the frequency of microalbuminuria (MA) and its associated medical risk factors in type II diabetic patients. Materials and Methods: Study population included 150 type II diabetic patients (70 women, 80 men) attending outpatient department of the hospital. Patients having clinical albuminuria and with other causes of proteinuria were excluded. Results: Women and men were of comparable ages. Women (26.4 kg/m/sup 2/) had higher body mass index (BMI) than men 24.3 kg/m/sup 2/). The frequency of MA was 46.7%, higher in males (50.6%) than females (41.5%). Fasting plasma glucose HbA/sub 1c/ levels were significantly higher in patients with MA compared to those with normo albuminuria (p < 0.001). The microalbuminuria patients had significantly decreased HDL-c levels compared to normoalbuminuric subjects (p< 0.001). However, no relation of MA with age, gender, known duration of diabetes, BMI, history of smoking, hypertension and serum: total cholesterol, LDL-c, triglyceride, urea and creatinine was found. Conclusion: There is a strong association of poor glycaemic control and decreased HDL-c levels with the presence of micro albuminuria. (author)

  19. ICC Type II large-format FPA detector assemblies

    Science.gov (United States)

    Clynne, Thomas H.; Powers, Thomas P.

    1997-08-01

    ICC presents a new addition to their integrated detector assembly product line with the announcement of their type II large format staring class FPA units. A result of internally funded research and development, the ICC type II detector assembly can accommodate all existing large format staring class PtSi, InSb and MCT focal planes, up to 640 by 480. Proprietary methodologies completely eliminate all FPA stresses to allow for maximum FPA survivability. Standard optical and cryocooler interfaces allow for the use of BEI, AEG, TI SADA Hughes/Magnavox and Joule Thompson coolers. This unit has been qualified to the current SADA II thermal environmental specifications and was tailored around ICC's worldwide industry standard type IV product. Assembled in a real world flexible manufacturing environment, this unit features a wide degree of adaptability and can be easily modified to a user's specifications via standard options and add-ons that include optical interfaces, electrical interfaces and window/filter material selections.

  20. Mucolipidosis type II in a domestic shorthair cat

    International Nuclear Information System (INIS)

    Hubler, M.; Haskins, M.E.; Arnold, S.; Kaser-Hotz, B.; Bosshard, N.U.; Briner, J.; Spycher, M.A.; Gitzelmann, R.; Sommerlade, H.J.; Figura, K. von

    1996-01-01

    A seven-month-old, female domestic shorthair cat was presented to the Veterinary Teaching Hospital, University of Zurich, with abnormal facial features, retarded growth and progressive hindlimb paresis. On physical examination the cat had a flat, broad face with hypertelorism, frontal bossing, small ears and thickened upper and lower eyelids. The corneas of both eyes were clear and the pupils were dilated. The skin was generally thickened, most prominently on the dorsal aspect of the neck. Radiography of the entire skeleton revealed a severely deformed spinal column, bilateral hip luxation with hip dysplasia, an abnormally shaped skull and generalised decreased bone opacity. The clinical features and radiographic changes were suggestive of mucopolysaccharidosis. The toluidine blue spot test on a urine sample, however, was negative for glycosaminoglycans. Further biochemical investigations revealed a deficiency of the enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase, EC 2.7.8.17) in peripheral leukocytes and an elevation of many lysosomal enzymes in the serum of the cat which is diagnostic for mucolipidosis type II. Histology and electron microscopy of different tissues are briefly summarised. The findings of this cat, the first reported case of mucolipidosis type II are compared with other similar storage diseases described in the cat

  1. Vitamin D - Dependent Rickets, Type II Case Report

    Science.gov (United States)

    Azemi, Mehmedali; Berisha, Majlinda; Ismaili-Jaha, Vlora; Kolgeci, Selim; Hoxha, Rina; Grajçevci-Uka, Violeta; Hoxha-Kamberi, Teuta

    2014-01-01

    Aim: The aim of this work the report of one case with vitamin D-dependent rickets, type II. Methods: Diagnosis has been established based on anamnesis, physical examination, laboratory findings and radiological examination. Results: A female child (age 25 months) has been hospitalized due to bone deformity, bone pain, alopecia and walking difficulties. The laboratory findings have revealed that the calcium values was low (1.20 mmol/L), phosphates in the reference value (1.30 mmol/L) the alkaline phosphatase value was quite high (852 IU/L), high value of parathyroid hormone (9.21 pmol/L), normal value of 25- hydroxyvitamin D, whereas the values of 1,25-dihydroxyvitamin D was high (185 μmol/L). Radiographic changes were evident and typical in the distal metaphysis of radius and ulna as well as in the bones of lower limbs (distal metaphysis of femur and proximal metaphysis of tibia and fibula). After treatment with calcium and calcitriol, the above mentioned clinical manifestations, laboratory test values and the radiographic changes in bones withdrew. Conclusions: Vitamin D-dependent rickets, type II is a rare genetic recessive disease, and its treatment includes a constant use of calcium and calcitriol. PMID:24757409

  2. Frequency of chronic complications of type II diabetes

    International Nuclear Information System (INIS)

    Basit, A.; Hydrie, M.Z.I.; Ahmedani, M.Y.; Masood, Q.; Hakeem, R.

    2004-01-01

    Objective: To assess the frequency of chronic complications of type II diabetes in subjects attending a tertiary care Unit in Karachi, Pakistan. Subjects and Methods: Computerized clinical records of 2199 type II diabetic subjects were analyzed for this study. The clinical and laboratory variables were statistically evaluated with significance at p. Results: Means of glycosylated hemoglobin HbA1c, fasting and random plasma glucose levels, systolic blood pressure, triglycerides and high density lipoproteins (HDL) were higher than the risk indicator value for both genders (p<0.005). Mean body mass index and total blood cholesterol was higher for females only. Hyperglycemia was present in 88%, high HbA1c in 81%, low HDL in 81%, obesity in 66% and hypertriglyceridemia in 54%, neuropathy in 36% proteinuria in 28% and hypertension in 50% of the subjects. Frequency of obesity, low HDL and hypertension was higher among females (p<0.001 in each case). Retinopathy (p<0.05), nephropathy (p<0.005), neuropathy (p<0.005) and foot ulcers (p<0.001) were higher among males. Frequency of obesity was significantly higher among those with shorter duration and in younger group while frequency of other complications was higher among those with longer duration and in the older groups. Conclusion: Higher rates of complications were observed compared to previous studies. Certain variables showed significant association with gender and age as described above. (author)

  3. Type II critical phenomena of neutron star collapse

    International Nuclear Information System (INIS)

    Noble, Scott C.; Choptuik, Matthew W.

    2008-01-01

    We investigate spherically symmetric, general relativistic systems of collapsing perfect fluid distributions. We consider neutron star models that are driven to collapse by the addition of an initially 'ingoing' velocity profile to the nominally static star solution. The neutron star models we use are Tolman-Oppenheimer-Volkoff solutions with an initially isentropic, gamma law equation of state. The initial values of (1) the amplitude of the velocity profile, and (2) the central density of the star, span a parameter space, and we focus only on that region that gives rise to type II critical behavior, wherein black holes of arbitrarily small mass can be formed. In contrast to previously published work, we find that--for a specific value of the adiabatic index (Γ=2)--the observed type II critical solution has approximately the same scaling exponent as that calculated for an ultrarelativistic fluid of the same index. Further, we find that the critical solution computed using the ideal-gas equations of state asymptotes to the ultrarelativistic critical solution.

  4. Characterization of hearing loss in aged type II diabetics

    Science.gov (United States)

    Frisina, Susan T.; Mapes, Frances; Kim, SungHee; Frisina, D. Robert; Frisina, Robert D.

    2009-01-01

    Presbycusis – age-related hearing loss – is the number one communicative disorder and a significant chronic medical condition of the aged. Little is known about how type II diabetes, another prevalent age-related medical condition, and presbycusis interact. The present investigation aimed to comprehensively characterize the nature of hearing impairment in aged type II diabetics. Hearing tests measuring both peripheral (cochlea) and central (brainstem and cortex) auditory processing were utilized. The majority of differences between the hearing abilities of the aged diabetics and their age-matched controls were found in measures of inner ear function. For example, large differences were found in pure-tone audiograms, wideband noise and speech reception thresholds, and otoacoustic emissions. The greatest deficits tended to be at low frequencies. In addition, there was a strong tendency for diabetes to affect the right ear more than the left. One possible interpretation is that as one develops presbycusis, the right ear advantage is lost, and this decline is accelerated by diabetes. In contrast, auditory processing tests that measure both peripheral and central processing showed fewer declines between the elderly diabetics and the control group. Consequences of elevated blood sugar levels as possible underlying physiological mechanisms for the hearing loss are discussed. PMID:16309862

  5. Type II decompression sickness in a hyperbaric inside attendant.

    Science.gov (United States)

    Johnson-Arbor, Kelly

    2012-01-01

    Decompression sickness (DCS) of an inside attendant (IA) is rarely encountered in hyperbarics. This report describes an IA who developed Type II DCS after a routine hyperbaric exposure. A 50-year-old male complained of lower extremity weakness and paresthesias after serving as an IA during a hyperbaric treatment to 40 fsw (122.52 kPa). Within 10 minutes after the conclusion of the treatment, the IA experienced irritability and confusion, and was unable to walk. Physical examination revealed decreased sensation below the T7 level, and decreased strength in the lower extremities. Type II DCS was diagnosed, and the IA was recompressed to 60 fsw (183.78 kPa) on a U.S. Navy Treatment Table 6, which resulted in improvement of his symptoms. Transthoracic echocardiography with bubble study performed 16 months after the event demonstrated a large patent foramen ovale (PFO). Increased age, decreased physical fitness and the undiagnosed PFO may have predisposed this attendant to developing DCS. Although rare, DCS may occur in IAs. Routine monitoring and reporting of the long-term health of hyperbaric IAs should be considered by hyperbaric facilities and medical directors in ord