WorldWideScience

Sample records for absorption line systems

  1. Kinematic Interpretation of the Centaurus A Absorption-Line System

    Eckart, A.; Wild, W.; Ageorges, N.

    1999-01-01

    The location of the gas responsible for the absorption-line system toward the nucleus of Centaurus A is a puzzle. It is generally accepted that the line features close to the systemic velocity originate in the disk. The redshifted line features in particular, however, are usually thought to be due t

  2. The low-ion QSO absorption-line systems

    Various techniques are used to investigate the class of QSO absorption-line systems that exhibit low-ion absorption lines. Four separate investigations are conducted as follows: Spectroscopy of 32 QSOs at red wavelengths is presented and used to investigate intermediate-redshift MgII absorption. A total of 22 Mg II doublets are detected, from which properties of the Mg II absorbers are derived. Marginal evidence for intrinsic evolution of the number density of the Mg II absorbers with redshift is found. The data are combined with previous observations of C IV and C II seen in the same QSOs at blue wavelengths, and the properties of Mg II- and C IV-selected systems are compared. A sample is constructed of 129 QSOs for which are available published data suitable for detecting absorption-line systems that are optically thick to Lyman continuum radiation. A total of 53 such Lyman-limit systems are found, from which properties of the Lyman-limit systems are derived. It is found that the rate of incidence of the systems does not strongly evolved with redshift. This result is contrasted with the evolution found previously for systems selected on the basis of Mg II absorption. Spectroscopy at red wavelengths of eight QSOs with known damped Lyα absorption systems is presented. Spectroscopic and spectrophotometric observations aimed at detecting molecular hydrogen and dust in the z = 2.796 damped Lyα absorber toward Q1337 + 113 are presented

  3. The low-ion QSO absorption-line systems

    Lanzetta, K.M.

    1988-01-01

    Various techniques are used to investigate the class of QSO absorption-line systems that exhibit low-ion absorption lines. Four separate investigations are conducted as follows: Spectroscopy of 32 QSOs at red wavelengths is presented and used to investigate intermediate-redshift MgII absorption. A total of 22 Mg II doublets are detected, from which properties of the Mg II absorbers are derived. Marginal evidence for intrinsic evolution of the number density of the Mg II absorbers with redshift is found. The data are combined with previous observations of C IV and C II seen in the same QSOs at blue wavelengths, and the properties of Mg II- and C IV-selected systems are compared. A sample is constructed of 129 QSOs for which are available published data suitable for detecting absorption-line systems that are optically thick to Lyman continuum radiation. A total of 53 such Lyman-limit systems are found, from which properties of the Lyman-limit systems are derived. It is found that the rate of incidence of the systems does not strongly evolved with redshift. This result is contrasted with the evolution found previously for systems selected on the basis of Mg II absorption. Spectroscopy at red wavelengths of eight QSOs with known damped Ly{alpha} absorption systems is presented. Spectroscopic and spectrophotometric observations aimed at detecting molecular hydrogen and dust in the z = 2.796 damped Ly{alpha} absorber toward Q1337 + 113 are presented.

  4. Determining the Fraction of Intrinsic CIV Absorption in Quasi-Stellar Object Absorption Line Systems

    Richards, G T; Yanny, B; Kollgaard, R I; Laurent-Mühleisen, S A; Vanden Berk, Daniel E; Richards, Gordon T.; York, Donald G.; Yanny, Brian; Kollgaard, Ronald I.; Berk, Daniel E. Vanden

    1999-01-01

    We present the results of a study of QSO Absorption Line Systems (QSOALSs) with respect to intrinsic QSO properties using an updated catalog of data in the literature. We have searched the literature for 6 and 20 cm radio flux densities and have studied 20 cm maps from the FIRST VLA Survey in order to compare the absorption properties with radio luminosity, radio spectral index and radio morphology. This work focuses particularly on the nature of CIV QSOALSs and their distribution in velocity space in light of intrinsic QSO properties. We find that the distribution of narrow, CIV absorption systems with relative velocities exceeding 5000 km/s is dependent not only on the optical luminosity of the QSOs, but also on the radio luminosity, the radio spectral index and the radio morphology of the QSOs. These observations are apparently inconsistent with the hypothesis that these systems are entirely due to intervening galaxies and it would seem that the contamination of the intervening systems (from 5000 to 75000 ...

  5. PKS 0119-46 and the origin of infalling absorption-line systems in quasars

    It is proposed that the infalling (z/sub abs/>z/sub em/) absorption-line systems in the quasar PKS 0119--046 are due to a blueshifting of the broad emission lines with respect to the rest frame of the underlying galaxy in which the quasar is located rather than being due to a real high-velocity infall. The spectrum of PKS 0119-046 shows a narrow emission-line spike at 3610 A. This is interpreted as Lyman-α emission from the narrow-line region of the quasar. The emission is at a redshift very close to that of the highest redshift absorption-line systems. The spectrum of PKS 0119-046 is consistent with it having a lightly reddened narrow-line region similar to that which might be seen in a typical low-redshift quasar. The physical parameters deduced for one of the absorption-line systems are completely compatible with that system being caused by a narrow emission-line cloud seen in absorption

  6. The Gaseous Extent of Galaxies and The Origin of QSO Absorption Line Systems

    Chen, H. -W.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.; Fernández-Soto, A.

    1998-01-01

    We present results of an ongoing program to study the gaseous extent of galaxies and the origin of QSO absorption line systems. For \\lya absorption systems, we find that absorption equivalent width depends strongly on galaxy impact parameter and galaxy $B$-band luminosity, and that the gaseous extent of individual galaxies scales with galaxy $B$-band luminosity as $r\\propto L_B^{0.40\\pm0.09}$. Applying the results to galaxies in the Hubble Deep Field to calculate the predicted number density ...

  7. The Gaseous Extent of Galaxies and The Origin of QSO Absorption Line Systems

    Chen, H W; Webb, J K; Barcons, X; Fernández-Soto, A

    1998-01-01

    We present results of an ongoing program to study the gaseous extent of galaxies and the origin of QSO absorption line systems. For \\lya absorption systems, we find that absorption equivalent width depends strongly on galaxy impact parameter and galaxy $B$-band luminosity, and that the gaseous extent of individual galaxies scales with galaxy $B$-band luminosity as $r\\propto L_B^{0.40\\pm0.09}$. Applying the results to galaxies in the Hubble Deep Field to calculate the predicted number density of \\lya absorption lines as a function of redshift and comparing it with observations, we find that at least 50% and perhaps as much as 100% of \\lya absorption systems with $W\\apg0.32$ Å can be explained by the extended gaseous envelops of normal galaxies. The anti-correlation analysis has also been performed on \\civ absorption line systems, and the results show that the ionized gas cross section scales with galaxy $B$-band luminosity as $r\\propto L_B^{0.76\\pm0.26}$.

  8. Origin and Properties of Strong Mg II Quasar Absorption Line Systems

    2001-01-01

    Strong Mg II quasar absorption line systems provide us with a useful tool to understand the gas that plays an important role in galaxy formation. In this paper, placing the theories of galaxy formation in a cosmological context, we present semi-analytic models and Monte-Carlo simulations for strong Mg II absorbers produced in gaseous galactic haloes and/or galaxy discs. We investigate the redshift path density for the MgII absorption lines and the properties of galaxy/absorber pairs, in particular the anti-correlation between the equivalent width of Mg II absorption line and the projected galaxy-to-sightline distance. The simulated result of the mean redshift path density of strong Mg II systems is consistent with the observational result. The fraction of strong Mg II systems arising from galaxy disks is predicted to be ~ 10% of the total. There exists an anti-correlation between the absorption line equivalent and the projected distance of sightline to galaxy center and galaxy luminosity. We determined that the mean absorbing radius Rabs ≈ 29h-1 kpc(LB/LB*)0.35. After taking selection effects into consideration, this becomes Rabs ≈ 38 h-1 kpc(LB/LB*)0.18, which is in good agreement with the observational result. This shows the importance of considering selection effects when comparing models with observations.

  9. Dust depletion of Ca and Ti in QSO absorption line systems

    Guber, C R

    2016-01-01

    To explore the role of titanium- and calcium-dust depletion in gas in and around galaxies we systematically study Ti/Ca abundance ratios in intervening absorption-line systems at low and high redshift. We investigate high-resolution optical spectra obtained by the UVES instrument at the Very Large Telescope and spectroscopically analyze 34 absorption-line systems at z<=0.5 to measure column densities (or limits) for CaII and TiII. We complement our UVES data set with previously published absorption-line data on Ti/Ca for redshifts up to z~3.8. Our absorber sample contains 110 absorbers (DLAs, sub-DLAs & LLSs). We compare our Ti/Ca findings with results from the Milky Way and the Magellanic Clouds and discuss the properties of Ti/Ca absorbers in the general context of quasar absorption-line systems.Our analysis indicates that there are two distinct populations of absorbers with either high or low Ti/Ca ratios with a separation at [Ti/Ca}]~1. While the calcium dust depletion in most of the absorbers appe...

  10. QSO Absorption Lines from QSOs

    Bowen, D V; Ménard, B; Chelouche, D; Inada, N; Oguri, M; Richards, G T; Strauss, M A; Vanden Berk, Daniel E; York, D G; Bowen, David V.; Hennawi, Joseph F.; Menard, Brice; Chelouche, Doron; Inada, Naohisa; Oguri, Masamune; Richards, Gordon T.; Strauss, Michael A.; Berk, Daniel E. Vanden; York, Donald G.

    2006-01-01

    We present the results of a search for metal absorption lines in the spectra of background QSOs whose sightlines pass close to foreground QSOs. We detect MgII(2796,2803) absorption in Sloan Digital Sky Survey (SDSS) spectra of four z>1.5 QSOs whose lines of sight pass within 26-98 kpc of lower redshift (z~0.5-1.5) QSOs. The 100% [4/4 pairs] detection of MgII in the background QSOs is clearly at odds with the incidence of associated (z_abs ~ z_em) systems -- absorbers which exist towards only a few percent of QSOs. Although the quality of our foreground QSO spectra is not as high as the SDSS data, absorption seen towards one of the background QSOs clearly does not show up at the same strength in the spectrum of the corresponding foreground QSO. This implies that the absorbing gas is distributed inhomogeneously around the QSO, presumably as a direct consequence of the anisotropic emission from the central AGN. We discuss possible origins for the MgII lines, including: absorption by gas from the foreground QSO h...

  11. Strong Absorption-line Systems at Low Redshift MgII and Damped Lyman Alpha

    Nestor, D B; Turnshek, D A; Nestor, Daniel B.; Rao, Sandhya; Turnshek, David

    2002-01-01

    We detail a powerful indirect method for the study of damped Lyman alpha systems (DLAs) at low redshift. We increase the probability of finding a low-redshift DLA to nearly 50% by targeting QSOs that are known to have strong low-redshift MgII and FeII absorption lines in their spectra. We are using Sloan Digital Sky Survey QSO spectra complemented by a survey we are conducting at the MMT to study the metal-line systems. The Hubble Space Telescope is being used to confirm low-redshift DLAs. In addition, we are imaging low-redshift DLA galaxies with several ground-based telescopes to directly study their environments.

  12. UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

    Ji, Tuo; Zhou, Hongyan; Jiang, Peng; Wang, Tinggui; Wang, Huiyuan; Liu, Wenjuan; Yang, Chenwei [Polar Research Institute of China, 451 Jinqiao Road, Pudong, Shanghai 200136 (China); Ge, Jian; Hamann, Fred [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Komossa, S.; Yuan, Weimin [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Beijing 100012 (China); Zuther, Jens [Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln (Germany); Lu, Honglin [Key Laboratory for Research in Galaxies and Cosmology, The University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui, 230026 (China); Zuo, Wenwen, E-mail: jituo@pric.gov.cn [Shanghai Astronomical Observatory, Nandan Road 80, Shanghai 200030 (China)

    2015-02-10

    We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width Δv ∼ 1500 km s{sup –1} centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n {sub H} ∼ (1.0-2.5) × 10{sup 5} cm{sup –3} and a column density of N {sub H} ∼ (1.0-3.2) × 10{sup 21} cm{sup –2} and is located at R ∼100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

  13. Dust Sensitivity of Absorption-Line Indices

    MacArthur, L A

    2004-01-01

    We investigate the effects of dust extinction on integrated absorption-line indices that are widely used to derive constraints on the ages and metallicities of composite stellar systems. Typically, absorption-line studies have been performed on globular clusters or elliptical galaxies, which are mostly dust-free systems. However, many recent studies of integrated stellar populations have focused on spiral galaxies which may contain significant amounts of dust. It is almost universally assumed that the effects of dust extinction on absorption-line measurements are entirely negligible given the narrow baseline of the spectral features, but no rigorous study has yet been performed to verify this conjecture. In this analysis, we explore the sensitivity of the standard set of Lick absorption-line indices, the higher-order Balmer line indices, the 4000 A break, the near-IR calcium triplet indices, and the Rose indices to dust absorption according to population synthesis models that incorporate a multi-component mod...

  14. Quasars as the formation sites of high-redshift ellipticals: a signature in the `associated' absorption-line systems?

    Franceschini, A.; Gratton, R.

    1997-03-01

    Published data on the average metallicities and abundance ratios for absorption-line systems in high-redshift quasars suggest that a dichotomy may exist between the chemical composition of damped Lyman alpha (Lyalpha) systems (interpreted as intervening galaxies in the QSO line of sight) and the z_abs~=z_em absorption- line systems associated with the quasar. Intervening systems have smaller than solar metallicities, whereas associated absorbers have solar or greater than solar metallicities and small N/C ratios. While these results have to be confirmed by more precise abundance determinations, we argue that they may be explained by an early phase of efficient metal enrichment occurring only in the close environment of high-z QSOs, and characterized by an excess type-II supernova (SNII) activity. This is reminiscent of the SNII phase required to explain the abundance ratios (favouring alpha- over Fe-group elements) observed in the intracluster (IC) medium of local galaxy clusters. We explore the following scenario, to be tested by forthcoming observations of QSO absorption lines using very large optical telescopes. (a) Well-studied damped- Lyalpha, Lyalpha and metal lines in intervening systems trace only part of the history of metal production in the Universe - the one concerning slowly star-forming discs or dwarf irregulars. (b) The complementary class of early-type and bulge-dominated galaxies formed quickly (at z>~4-5) through a huge episode of star formation favouring high-mass stars. (c) The nucleus of the latter is the site of the subsequent formation of a quasar, which partly hides from view the dimmer host galaxy. (d) The products of a galactic wind, following the violent episode of star formation in the host galaxy and metal pollution of the IC medium in the forming cluster, could be directly observable in the z_abs~=z_em associated absorption systems on the QSO line of sight.

  15. Average Properties of a Large Sample of z_abs ~ z_em associated Mg II Absorption Line Systems

    Berk, D Vanden; York, D G; Richards, G T; Lundgren, B; Alsayyad, Y; Kulkarni, V P; Subba-Rao, M; Schneider, D P; Heckman, T; Anderson, S; Crotts, A P S; Frieman, J; Stoughton, C; Lauroesch, J T; Hall, P B; Meiksin, A; Steffing, M; Vanlandingham, J

    2008-01-01

    We have studied a sample of 415 associated (z_ab z_em; relative velocity with respect to QSO 3000km/s), so as to understand their origin. From the analysis of the composite spectra, as well as from the comparison of measured equivalent widths in individual spectra, we conclude that the associated Mg II absorbers have higher apparent ionization, measured by the strength of the C IV absorption lines compared to the Mg II absorption lines, than the intervening absorbers. The ionization so measured appears to be related to apparent ejection velocity, being lower as the apparent ejection velocity is more and more positive. There is clear evidence, from the composite spectra, for SMC like dust attenuation in these systems; the 2175AA absorption feature is not present. The extinction is almost twice that observed in the similarly selected sample of intervening systems. We reconfirm that QSOs with non-zero FIRST radio flux are intrinsically redder than the QSOs with no detection in the FIRST survey. The incidence of ...

  16. Average Extinction Curves and Relative Abundances for QSO Absorption Line Systems at 1 <= z_abs < 2

    York, Donald G.; Khare, Pushpa; Berk, Daniel Vanden; Kulkarni, Varsha P.; Crotts, Arlin P. S.; Lauroesch, James T.; Richards, Gordon T.; Schneider, Donald P.; Welty, Daniel E.; AlSayyad, Yusra; Kumar, Abhishek; Lundgren, Britt; Shanidze, Natela; Smith, Tristan; Vanlandingham, Johnny

    2006-01-01

    We have studied a sample of 809 Mg II absorption systems with 1.0 < z_abs < 1.86 in the spectra of SDSS QSOs, with the aim of understanding the nature and abundance of the dust and the chemical abundances in the intervening absorbers. Normalized, composite spectra were derived, for abundance measurements, for the full sample and several sub-samples, chosen on the basis of the line strengths and other absorber and QSO properties. Average extinction curves were obtained for the sub-samples by c...

  17. Ultranarrow absorptive spectral line induced by microwave field

    Hu Zheng-Feng; Ma Yi-Sheng; Deng Jian-Liao; He Hui-Juan; Wang Yu-Zhu

    2009-01-01

    This paper investigates the absorptive spectral lines of four-level atomic system driven by a coupling, probe and microwave fields. Due to the perturbation of the microwave field, the original electromagnetically induced transparency is changed to electromagnetically induced absorption and the absorptive spectral line can be very narrow. This ultranarrow spectral line has potential applications to the microwave atomic frequency standard and the measurement of very weak magnetic field.

  18. Cosmic Metallicity from ZnII-Selected QSO Absorption Line Systems Near Redshift z=1.2

    Monier, Eric

    2010-09-01

    We have searched nearly 15,000 strong intervening MgII systems in SDSS quasar spectra to measure spectral regions where weak, unsaturated metal lines are predicted to exist, with the aim of finding a representative sample of the strongest metal-line column density systems in the universe. These systems are clearly damped Lyman-alpha {DLA} systems, which track cosmologically intervening neutral gas regions that fall along the sightlines to background quasars. We propose STIS G230L spectroscopy of seven strong-ZnII-selected systems from this sample in order to measure their Lyman-alpha absorption profiles and derive their HI column densities. Since Zn is not depleted onto grains, measurement of N{HI} allows a direct measurement of the metal abundance in such systems. We expect the results to be representative of the upper envelope of the distribution of neutral-gas-phase metallicities near redshift z=1.2. If these systems are high-N{HI} DLAs {e.g., 6E21 atoms/cm^2} they will have metallicities typical of those normally found in DLAs {e.g., one-tenth solar}. However, if they are low-N{HI} DLAs {e.g., 2E20 atoms/cm(2) }, they will have supersolar metallicities. Since these DLAs are selected on the basis of their extreme metal-line properties, analysis of their metallicities and dust-to-gas ratios will lead to strong constraints on the range of properties exhibited by DLA systems.

  19. Novel Moessbauer experiment in a rotating system and the extra-energy shift between emission and absorption lines

    Yarman, T; Arik, M; Akkus, B; Oktem, Y; Susam, L A; Missevitch, O V

    2015-01-01

    We present the results of a novel Mossbauer experiment in a rotating system, implemented recently in Istanbul University, which yields the coefficient k=0.69+/-0.02 within the frame of the expression for the relative energy shift between emission and absorption lines dE/E=ku2/c2. This result turned out to be in a quantitative agreement with an experiment achieved earlier on the subject matter (A.L. Kholmetskii et al. 2009 Phys. Scr. 79 065007), and once again strongly pointed to the inequality k>0.5, revealed originally in (A.L. Kholmetskii et al. 2008 Phys. Scr. 77, 035302 (2008)) via the re-analysis of Kundig experiment (W. Kundig. Phys. Rev. 129, 2371 (1963)). A possible explanation of the deviation of the coefficient k from the relativistic prediction k=0.5 is discussed.

  20. Molecular absorption in transition region spectral lines

    Schmit, Donald; Ayres, Thomas; Peter, Hardi; Curdt, Werner; Jaeggli, Sarah

    2014-01-01

    Aims: We present observations from the Interface Region Imaging Spectrograph (IRIS) of absorption features from a multitude of cool atomic and molecular lines within the profiles of Si IV transition region lines. Many of these spectral lines have not previously been detected in solar spectra. Methods: We examined spectra taken from deep exposures of plage on 12 October 2013. We observed unique absorption spectra over a magnetic element which is bright in transition region line emission and the ultraviolet continuum. We compared the absorption spectra with emission spectra that is likely related to fluorescence. Results: The absorption features require a population of sub-5000 K plasma to exist above the transition region. This peculiar stratification is an extreme deviation from the canonical structure of the chromosphere-corona boundary . The cool material is not associated with a filament or discernible coronal rain. This suggests that molecules may form in the upper solar atmosphere on small spatial scales...

  1. The theory of QSO absorption line systems and their relationship to the galaxies

    Charlton, Jane

    1993-01-01

    The fundamental goal of this effort is to paint a picture of what the Ly-alpha forest clouds are and how they are distributed in space. Progress during the first phase of this program involved development of the 'Cheshire Cat Model' of Ly-alpha clouds in which systems over a large range of column densities are produced by disks with somewhat smaller column densities than those of normal galaxies. A prediction of the slab model of Ly-alpha clouds was confirmed by a new observational result, and the comparison of models to the new data allowed an estimate of the pressure of the intergalactic medium. This result should be forthcoming in pre-print form within the next month. The various results will now be described in more detail.

  2. Average Extinction Curves and Relative Abundances for QSO Absorption Line Systems at 1 <= z_abs < 2

    York, D G; Baugher, B; Brinkmann, J; Crotts, A P S; Hall, P B; Jenkins, E B; Khare, P; Kulkarni, V P; Kumar, A; Lauroesch, J T; Lundgren, B; Ménard, B; Rao, S; Richards, G T; Schneider, D P; Shanidze, N; Smith, T; Tumlinson, J; Turnshek, D A; Vanden Berk, Daniel E; Vanlandingham, J; Welty, D E; Yip, C W; Alsayyad, Yusra; Baugher, Britt; Berk, Daniel Vanden; Brinkmann, Jon; Crotts, Arlin P. S.; Hall, Patrick B.; Jenkins, Edward B.; Khare, Pushpa; Kulkarni, Varsha P.; Kumar, Abhishek; Lauroesch, James T.; Lundgren, Britt; Menard, Brice; Rao, Sandhya; Richards, Gordon T.; Schneider, Donald P.; Shanidze, Natela; Smith, Tristan; Tumlinson, Jason; Turnshek, David; Vanlandingham, Johnny; Welty, Daniel E.; Yip, Ching-Wa; York, Donald G.

    2006-01-01

    We have studied a sample of 809 Mg II absorption systems with 1.0 < z_abs < 1.86 in the spectra of SDSS QSOs, with the aim of understanding the nature and abundance of the dust and the chemical abundances in the intervening absorbers. Normalized, composite spectra were derived, for abundance measurements, for the full sample and several sub-samples, chosen on the basis of the line strengths and other absorber and QSO properties. Average extinction curves were obtained for the sub-samples by comparing their geometric mean spectra with those of matching samples of QSOs without absorbers in their spectra. There is clear evidence for the presence of dust in the intervening absorbers. The 2175 A feature is not present in the extinction curves, for any of the sub-samples. The extinction curves are similar to the SMC extinction curve with a rising UV extinction below 2200 A. The absorber rest frame colour excess, E(B-V), derived from the extinction curves, depends on the absorber properties and ranges from <...

  3. On the pre-maximum and principal absorption line systems in the spectrum of the Nova Delphini 1967 (HR Del)

    The evolution of the pre-maximum and principal absorption spectra of HR Del is discussed on the basis of the analysis of existing data and author's measurements. It is found that the principal spectrum appeared few days before the maximum brightness of the star. The only regular spectral line components observed during the pre-maximum stage is that formed by continuous injection of the matter from the Nova surface (pre-maximum spectrum). At the same time the HR Del spectrum showed rather intensive short-lived components due to temporal eruptive injections from the star

  4. Narrow UV Absorption Line Outflows from Quasars

    Hamann, Fred; Hidalgo, Paola Rodriguez; Capellupo, Daniel

    2012-01-01

    Narrow absorption line (NAL) outflows are an important yet poorly understood part of the quasar outflow phenomenon. We discuss one particular NAL outflow that has high speeds, time variability, and moderate ionizations like typical BAL flows, at an estimated location just ~5 pc from the quasar. It also has a total column density and line widths (internal velocity dispersions) ~100 times smaller than BALs, with no substantial X-ray absorption. We argue that radiative shielding (in the form of an X-ray/warm absorber) is not critical for the outflow acceleration and that the moderate ionizations occur in dense substructures that have an overall small volume filling factor in the flow. We also present new estimates of the overall incidence of quasar outflow lines; e.g., ~43% of bright quasars have a C IV NAL outflow while ~68% have a C IV outflow line of any variety (NAL, BAL, or mini-BAL).

  5. Non-Voigt Lyalpha Absorption Line Profiles.

    Outram; Carswell; Theuns

    2000-02-01

    Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium and the loss of a physical justification for Voigt profile fitting of the Lyalpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We develop a method to detect departures from Voigt profiles of the absorption lines in a statistical way and apply this method to simulated Lyalpha forest spectra, confirming that the profiles seen do statistically differ from Voigt profiles. PMID:10622758

  6. Absorption-line measurements of AGN outflows

    Fields, Dale L.

    Investigations into the elemental abundances in two nearby active galaxies, the narrow-line Seyfert 1 Markarian 1044 and the Seyfert 1 Markarian 279, are reported. Spectra from three space-based observatories HST, FUSE, and CHANDRA, are used to measure absorption lines in material outflowing from the nucleus. I make multi-wavelength comparisons to better convert the ionic column densities into elemental column densities which can then be used to determine abundances (metallicities). Narrow-line Seyfert 1 galaxies are known to have extreme values of a number of properties compared to active galactic nuclei (AGNs) as a class. In particular, emission-line studies have suggested that NLS1s are unusually metal-rich compared to broad-line AGNs of comparable luminosity. To test these suggestions I perform absorption-line studies on the NLS1 Markarian 1044, a nearby and bright AGN. I use lines of H I, C IV, N V, and O VI to properly make the photoionization correction through the software Cloudy and determine abundances of Carbon, Nitrogen and Oxygen. I find two results. The first is that Markarian 1044 has a bulk metallicity greater than five times solar. The second is that the N/C ratio in Markarian 1044 is consistent with a solar mixture. This is in direct contradiction of extrapolations from local H II regions which state N/ C should scale with bulk metallicity. This implies a different enrichment history in Markarian 1044 than in the Galactic disk. I also report discovery of three new low-redshift Lya forest lines with log N HI >= 12:77 in the spectrum of Markarian 1044. This number is consistent with the 2.6 expected Lya forest lines in the path length to Markarian 1044. I also investigate the CHANDRA X-ray spectrum of Markarian 279, a broad-line Seyfert 1. I use a new code, PHASE, to self-consistently model the entire absorption spectrum simultaneously. Using solely the X-ray spectrum I am able to determine the physical parameters of this absorber to a degree only

  7. Intermediate-redshift galaxy halos - Results from QSO absorption lines

    For a sample of Mg II-selected QSO absorption-line systems for which the absorbing galaxies have been successfully identified, the rest-frame equivalent widths of the Mg II 2796-A absorption lines are examined as a function of the known impact parameters between the background QSOs and the absorbing galaxies. There appears to exist a relationship between the equivalent widths and the impact parameters, in the sense that larger equivalent widths occur at smaller impact parameters. No trend of the doublet ratio is found with impact parameter, and neither the equivalent widths nor the doublet ratios are correlated with the absolute luminosities or redshifts of the absorbing galaxies. These results apparently indicate that the main factor that determines the equivalent width of a particular absorption system is the impact parameter between the background QSO and the absorbing galaxy. 32 refs

  8. Intermediate-redshift galaxy halos - Results from QSO absorption lines

    Lanzetta, K.M.; Bowen, D. (Cambridge Univ. (England) Royal Greenwich Observatory, Cambridge (England))

    1990-07-01

    For a sample of Mg II-selected QSO absorption-line systems for which the absorbing galaxies have been successfully identified, the rest-frame equivalent widths of the Mg II 2796-A absorption lines are examined as a function of the known impact parameters between the background QSOs and the absorbing galaxies. There appears to exist a relationship between the equivalent widths and the impact parameters, in the sense that larger equivalent widths occur at smaller impact parameters. No trend of the doublet ratio is found with impact parameter, and neither the equivalent widths nor the doublet ratios are correlated with the absolute luminosities or redshifts of the absorbing galaxies. These results apparently indicate that the main factor that determines the equivalent width of a particular absorption system is the impact parameter between the background QSO and the absorbing galaxy. 32 refs.

  9. The earliest galaxies seen in 21 cm line absorption

    Xu, Yidong; Chen, Xuelei

    2010-01-01

    We investigate the 21 cm absorption lines produced by non-linear structures during the early stage of reionization, i.e. the starless minihalos and the dwarf galaxies. After a detailed modelling of their properties, with particular attention to the coupling physics, we determine their 21 cm absorption line profiles. The infalling gas velocity around minihalos/dwarf galaxies strongly affects the line shape, and with the low spin temperatures outside the virial radii of the systems, gives rise to horn-like line profiles. The optical depth of a dwarf galaxy is reduced for lines of sight penetrating through its HII region, and especially, a large HII region created by a dwarf galaxy with higher stellar mass and/or a top-heavy initial mass function results in an optical depth trough rather than an absorption line. We compute synthetic spectra of 21 cm forest for both high redshift quasars and radio afterglows of gamma ray bursts (GRBs). Even with the planned SKA, radio afterglows of most if not all GRBs would stil...

  10. The missing UV absorption lines of NGC 4151

    In this paper we discuss new, near-simultaneous high-dispersion long- and short-wavelength International Ultraviolet Explorer (IUE) observations of the Seyfert galaxy NGC 4151. Previous observations revealed a narrow absorption system in Mg II not present in Ly α or C IV. The new observations confirm the presence of this system in Mg II and its absence in the other lines. Possible reasons for this are discussed. (author)

  11. The dust, nebular emission, and dependence on QSO radio properties of the associated Mg II absorption line systems

    Khare, Pushpa [CSIR Emeritus Scientist, IUCAA, Ganeshkhind, Pune 411007 (India); Daniel, Vanden Berk [Physics Department, St. Vincent College, Latrobe, PA 15650 (United States); Rahmani, Hadi [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); York, Donald G., E-mail: pushpakhare@gmail.com [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2014-10-10

    We studied dust reddening and [O II] emission in 1730 Mg II associated absorption systems (AAS; relative velocity with respect to QSOs, ≤3000 km s{sup –1}; in units of velocity of light, β, ≤0.01) with 0.4 ≤z {sub abs} ≤ 2 in the Sloan Digital Sky Survey DR7, focusing on their dependence on the radio and other QSO properties. We used control samples, several with matching radio properties, to show that (1) AAS in radio-detected (RD) QSOs cause 2.6 ± 0.2 times higher dust extinction than those in radio-undetected (RUD) ones, which in turn cause 2.9 ± 0.7 times the dust extinction in the intervening systems; (2) AAS in core-dominated QSOs cause 2.0 ± 0.1 times higher dust extinction than those in lobe-dominated QSOs; (3) the occurrence of AAS is 2.1 ± 0.2 times more likely in RD QSOs than in RUD QSOs and 1.8 ± 0.1 time more likely in QSOs having black holes with masses larger than 1.23 × 10{sup 9} M {sub ☉} than in those with lower-mass black holes; and (4) there is excess flux in [O II]λ3727 emission in the composite spectra of the AAS samples compared with those of the control samples, which is at the emission redshift. The presence of AAS enhances the O II emission from the active galactic nucleus and/or the host galaxy. This excess is similar for both RD and RUD samples and is 2.5 ± 0.4 times higher in lobe-dominated samples than in core-dominated samples. The excess depends on the black hole mass and Eddington ratio. All these point to the intrinsic nature of the AAS except for the systems with z {sub abs} > z {sub em}, which could be infalling galaxies.

  12. Model galactic coronae: Ionization structure and absorption-line spectra

    We describe a general model for a gaseous galactic corona, and demonstrate that it is in harmony with a variety of observational and theoretical constraints. We then compute the ionization equilibria of H, He, C, N, O, Si, and S atoms in the corona and determine the strengths of resonance absorption lines arising therein. To this end, we obtain approximate cross sections for ionization of the heavy-element ions by photons of energy E/sub γ/< or =100 eV.We use our results first to discuss the expected absorption spectrum of our Galaxy's corona. Subsequently, we discuss in detail the relevance of our computed equilibria to the suggestion that galactic coronae produce some redshift systems in quasar absorption spectra. Because our model coronae are not isothermal, the ionization structure existing along various lines of sight through them is not in accord with the concept of ''reasonable ionization equilibrium'': a concept assumed to be valid in most analyses of quasar spectra. However, our calculations indicate that typically one well-established redshift system in each quasar absorption spectrum could arise in the corona of an intervening galaxy. This is the number expected from statistical arguments if quasar redshifts are fully cosmological in origin

  13. Monitoring the Variability of Intrinsic Absorption Lines in Quasar Spectra

    Misawa, Toru; Eracleous, Michael

    2014-01-01

    We have monitored 12 intrinsic narrow absorption lines (NALs) in five quasars and seven mini-broad absorption lines (mini-BALs) in six quasars for a period of 4-12 years (1-3.5 years in the quasar rest-frame). We present the observational data and the conclusions that follow immediately from them, as a prelude to a more detailed analysis. We found clear variability in the equivalent widths (EWs) of the mini-BAL systems but no easily discernible changes in their profiles. We did not detect any variability in the NAL systems nor in narrow components that are often located at the center of mini-BAL profiles. Variations in mini-BAL EWs are larger at longer time intervals, reminiscent of the trend seen in variable broad absorption lines. If we assume that the observed variations result from changes in the ionization state of the mini-BAL gas, we infer lower limits to the gas density $\\sim$ 10$^3$-10$^5$ cm$^{-3}$ and upper limits on the distance of the absorbers from the central engine of order a few kpc. Motivate...

  14. Interferometric measurement of lines shift in flames in connection with interpretation of lined absorption method in atomic absorption spectroscopy

    This paper is concerned with interferometric measuring of the line shift in flames in the view of interpretation of absorption lines in the atomic absorption spectroscopy. The newly measured line shifts were compared to the known data on Lorentz broadening of the same lines obtained by methods free of the systematic errors. The resonant lines of the alkaline earth elements (Sr, Ca, Ba) were investigated. To reduce self-absorption in the flame the solutions with minimum concentrations of the elements were used. The computation scheme includes the spectrometer apparatus width and line broadening due to the self-absorption. Formulae are given for computing the values studied. Good agreement was observed between the computed and experimental results. Error analysis was performed. It was concluded that any line shifts in the hydrocarbons were correctly taken into an account in the absolute computations of absorption

  15. Radiation pressure confinement - IV. Application to broad absorption line outflows

    Baskin, Alexei; Stern, Jonathan

    2014-01-01

    A fraction of quasars present broad absorption lines, produced by outflowing gas with typical velocities of 3000 - 10,000 km/s. If the outflowing gas fills a significant fraction of the volume where it resides, then it will be highly ionized by the quasar due to its low density, and will not produce the observed UV absorption. The suggestion that the outflow is shielded from the ionizing radiation was excluded by recent observations. The remaining solution is a dense outflow with a filling factor $f<10^{-3}$. What produces such a small $f$? Here we point out that radiation pressure confinement (RPC) inevitably leads to gas compression and the formation of dense thin gas sheets/filaments, with a large gradient in density and ionization along the line of sight. The total column of ionized dustless gas is a few times $10^{22}$ cm$^{-2}$, consistent with the observed X-ray absorption and detectable P V absorption. The predicted maximal columns of various ions show a small dependence on the system parameters, a...

  16. An automated flow injection system for metal determination by flame atomic absorption spectrometry involving on-line fabric disk sorptive extraction technique.

    Anthemidis, A; Kazantzi, V; Samanidou, V; Kabir, A; Furton, K G

    2016-08-15

    A novel flow injection-fabric disk sorptive extraction (FI-FDSE) system was developed for automated determination of trace metals. The platform was based on a minicolumn packed with sol-gel coated fabric media in the form of disks, incorporated into an on-line solid-phase extraction system, coupled with flame atomic absorption spectrometry (FAAS). This configuration provides minor backpressure, resulting in high loading flow rates and shorter analytical cycles. The potentials of this technique were demonstrated for trace lead and cadmium determination in environmental water samples. The applicability of different sol-gel coated FPSE media was investigated. The on-line formed complex of metal with ammonium pyrrolidine dithiocarbamate (APDC) was retained onto the fabric surface and methyl isobutyl ketone (MIBK) was used to elute the analytes prior to atomization. For 90s preconcentration time, enrichment factors of 140 and 38 and detection limits (3σ) of 1.8 and 0.4μgL(-1) were achieved for lead and cadmium determination, respectively, with a sampling frequency of 30h(-1). The accuracy of the proposed method was estimated by analyzing standard reference materials and spiked water samples. PMID:27260436

  17. Assessment of cadmium and iron adsorption in sediment, employing a flow injection analysis system with on line filtration and detection by flame atomic absorption spectrometry and thermospray flame furnace atomic absorption spectrometry

    Graphical abstract: -- Highlights: •A FIA system with on-line filtration for isotherms adsorption studies was proposed. •Isotherms for iron and cadmium elements in bottom lake sediment were done. •Inferences about adsorption/desorption mechanisms were feasible. •The proposed method turns the isotherm studies fast and reliable. -- Abstract: This work presents an evaluation of iron and cadmium adsorption in sediment of the Furnas Hydroelectric Plant Reservatory located in Alfenas, Minas Gerais (Brazil). The metal determination was done employing a flow injection analysis (FIA) with an on-line filtering system. As detection techniques, flame atomic absorption spectrometry (FAAS) for iron and thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) for cadmium determinations were used. The developed methodology presented good limits of detection, being 190 μg L−1 for iron and 1.36 μg L−1 for cadmium, and high sampling frequency for both metals 144 and 60 readings h−1 for iron and cadmium, respectively. Both metals obey the Langmuir model, with maximum adsorptive capacity of 0⋅169 mg g−1 for iron and 7⋅991 mg g−1 for cadmium. For iron, a pseudo-first-order kinetic model was obtained with a theoretical Qe = 9⋅8355 mg g−1 (experimental Qe = 9⋅5432 mg g−1), while for cadmium, a pseudo-second-order kinetic model was obtained, with a theoretical Qe = 0.3123 mg g−1 (experimental Qe = 0⋅3052 mg g−1)

  18. Tunable diode laser absorption spectroscopy-based tomography system for on-line monitoring of two-dimensional distributions of temperature and H2O mole fraction

    To monitor two-dimensional (2D) distributions of temperature and H2O mole fraction, an on-line tomography system based on tunable diode laser absorption spectroscopy (TDLAS) was developed. To the best of the authors’ knowledge, this is the first report on a multi-view TDLAS-based system for simultaneous tomographic visualization of temperature and H2O mole fraction in real time. The system consists of two distributed feedback (DFB) laser diodes, a tomographic sensor, electronic circuits, and a computer. The central frequencies of the two DFB laser diodes are at 7444.36 cm−1 (1343.3 nm) and 7185.6 cm−1 (1391.67 nm), respectively. The tomographic sensor is used to generate fan-beam illumination from five views and to produce 60 ray measurements. The electronic circuits not only provide stable temperature and precise current controlling signals for the laser diodes but also can accurately sample the transmitted laser intensities and extract integrated absorbances in real time. Finally, the integrated absorbances are transferred to the computer, in which the 2D distributions of temperature and H2O mole fraction are reconstructed by using a modified Landweber algorithm. In the experiments, the TDLAS-based tomography system was validated by using asymmetric premixed flames with fixed and time-varying equivalent ratios, respectively. The results demonstrate that the system is able to reconstruct the profiles of the 2D distributions of temperature and H2O mole fraction of the flame and effectively capture the dynamics of the combustion process, which exhibits good potential for flame monitoring and on-line combustion diagnosis

  19. Tunable diode laser absorption spectroscopy-based tomography system for on-line monitoring of two-dimensional distributions of temperature and H2O mole fraction

    Xu, Lijun; Liu, Chang; Jing, Wenyang; Cao, Zhang; Xue, Xin; Lin, Yuzhen

    2016-01-01

    To monitor two-dimensional (2D) distributions of temperature and H2O mole fraction, an on-line tomography system based on tunable diode laser absorption spectroscopy (TDLAS) was developed. To the best of the authors' knowledge, this is the first report on a multi-view TDLAS-based system for simultaneous tomographic visualization of temperature and H2O mole fraction in real time. The system consists of two distributed feedback (DFB) laser diodes, a tomographic sensor, electronic circuits, and a computer. The central frequencies of the two DFB laser diodes are at 7444.36 cm-1 (1343.3 nm) and 7185.6 cm-1 (1391.67 nm), respectively. The tomographic sensor is used to generate fan-beam illumination from five views and to produce 60 ray measurements. The electronic circuits not only provide stable temperature and precise current controlling signals for the laser diodes but also can accurately sample the transmitted laser intensities and extract integrated absorbances in real time. Finally, the integrated absorbances are transferred to the computer, in which the 2D distributions of temperature and H2O mole fraction are reconstructed by using a modified Landweber algorithm. In the experiments, the TDLAS-based tomography system was validated by using asymmetric premixed flames with fixed and time-varying equivalent ratios, respectively. The results demonstrate that the system is able to reconstruct the profiles of the 2D distributions of temperature and H2O mole fraction of the flame and effectively capture the dynamics of the combustion process, which exhibits good potential for flame monitoring and on-line combustion diagnosis.

  20. On-line sequential injection dispersive liquid-liquid microextraction system for flame atomic absorption spectrometric determination of copper and lead in water samples.

    Anthemidis, Aristidis N; Ioannou, Kallirroy-Ioanna G

    2009-06-30

    A simple, sensitive and powerful on-line sequential injection (SI) dispersive liquid-liquid microextraction (DLLME) system was developed as an alternative approach for on-line metal preconcentration and separation, using extraction solvent at microlitre volume. The potentials of this novel schema, coupled to flame atomic absorption spectrometry (FAAS), were demonstrated for trace copper and lead determination in water samples. The stream of methanol (disperser solvent) containing 2.0% (v/v) xylene (extraction solvent) and 0.3% (m/v) ammonium diethyldithiophosphate (chelating agent) was merged on-line with the stream of sample (aqueous phase), resulting a cloudy mixture, which was consisted of fine droplets of the extraction solvent dispersed entirely into the aqueous phase. By this continuous process, metal chelating complexes were formed and extracted into the fine droplets of the extraction solvent. The hydrophobic droplets of organic phase were retained into a microcolumn packed with PTFE-turnings. A portion of 300 microL isobutylmethylketone was used for quantitative elution of the analytes, which transported directly to the nebulizer of FAAS. All the critical parameters of the system such as type of extraction solvent, flow-rate of disperser and sample, extraction time as well as the chemical parameters were studied. Under the optimum conditions the enhancement factor for copper and lead was 560 and 265, respectively. For copper, the detection limit and the precision (R.S.D.) were 0.04 microg L(-1) and 2.1% at 2.0 microg L(-1) Cu(II), respectively, while for lead were 0.54 microg L(-1) and 1.9% at 30.0 microg L(-1) Pb(II), respectively. The developed method was evaluated by analyzing certified reference material and applied successfully to the analysis of environmental water samples. PMID:19376348

  1. Development of on-line single-drop micro-extraction sequential injection system for electrothermal atomic absorption spectrometric determination of trace metals

    A novel automatic sequential injection (SI) single-drop micro-extraction (SDME) system is proposed as versatile approach for on-line metal preconcentration and/or separation. Coupled to electrothermal atomic absorption spectrometry (ETAAS) the potentials of this SI scheme are demonstrated for trace cadmium determination in water samples. A non-charged complex of cadmium with ammonium diethyldithiophosphate (DDPA) was produced and extracted on-line into a 60 μL micro-drop of di-isobutyl ketone (DIBK). The extraction procedure was performed into a newly designed flow-through extraction cell coupled on a sequential injection manifold. As the complex Cd(II)-DDPA flowed continuously around the micro-droplet, the analyte was extracting into the solvent micro-drop. All the critical parameters were optimized and offered good performance characteristics and high preconcentration ratios. For 600 s micro-extraction time, the enhancement factor was 10 and the sampling frequency was 6 h-1. The detection limit was 0.01 μg L-1 and the precision (RSD at 0.1 μg L-1 of cadmium) was 3.9%. The proposed method was evaluated by analyzing certified reference material

  2. DISCOVERY OF THE TRANSITION OF A MINI-BROAD ABSORPTION LINE INTO A BROAD ABSORPTION LINE IN THE SDSS QUASAR J115122.14+020426.3

    Hidalgo, Paola Rodriguez; Eracleous, Michael; Charlton, Jane [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Hamann, Fred [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Murphy, Michael T. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122 (Australia); Nestor, Daniel [Department of Physics and Astronomy, University of California, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095 (United States)

    2013-09-20

    We present the detection of a rare case of dramatic strengthening in the UV absorption profiles in the spectrum of the quasar J115122.14+020426.3 between observations {approx}2.86 yr apart in the quasar rest frame. A spectrum obtained in 2001 by the Sloan Digital Sky Survey shows a C IV ''mini-broad'' absorption line (FWHM = 1220 km s{sup -1}) with a maximum blueshift velocity of {approx}9520 km s{sup -1}, while a later spectrum from the Very Large Telescope shows a significantly broader and stronger absorption line, with a maximum blueshift velocity of {approx}12, 240 km s{sup -1} that qualifies as a broad absorption line. A similar variability pattern is observed in two additional systems at lower blueshifted velocities and in the Ly{alpha} and N V transitions as well. One of the absorption systems appears to be resolved and shows evidence for partial covering of the quasar continuum source (C{sub f} {approx} 0.65), indicating a transverse absorber size of, at least, {approx}6 Multiplication-Sign 10{sup 16} cm. In contrast, a cluster of narrower C IV lines appears to originate in gas that fully covers the continuum and broad emission line sources. There is no evidence for changes in the centroid velocity of the absorption troughs. This case suggests that at least some of the absorbers that produce ''mini-broad'' and broad absorption lines in quasar spectra do not belong to intrinsically separate classes. Here, the ''mini-broad'' absorption line is most likely interpreted as an intermediate phase before the appearance of a broad absorption line due to their similar velocities. While the current observations do not provide enough constraints to discern among the possible causes for this variability, future monitoring of multiple transitions at high resolution will help achieve this goal.

  3. On-line preconcentration system using a microcolumn packed with Alizarin Red S-modified alumina for zinc determination by flame atomic absorption spectrometry

    A.M. Haji Shabani

    2009-01-01

    Full Text Available A simple and sensitive on-line flow injection system for determination of zinc with FAAS has been described. The method is based on the separation and preconcentration of zinc on a microcolumn of immobilized Alizarin Red S on alumina. The adsorbed analyte is then eluted with 250 µL of nitric acid (1 mol L-1 and is transported to flame atomic absorption spectrometer for quantification. The effect of pH, sample and eluent flow rates and presence of various cations and anions on the retention of zinc was investigated. The sorption of zinc was quantitative in the pH range of 5.5-8.5. For a sample volume of 25 mL an enrichment factor of 144 and a detection limit (3S of 0.2 µg L-1 was obtained. The precision (RSD, n=7 was 3.0% at the 20 µg L-1 level. The developed system was successfully applied to the determination of zinc in water samples, hair, urine and saliva.

  4. Evaluation of polychlorotrifluoroethylene as sorbent material for on-line solid phase extraction systems: Determination of copper and lead by flame atomic absorption spectrometry in water samples

    Polychlorotrifluoroethylene (PCTFE) in the form of beads was applied, as packing material for flow injection on-line column preconcentration and separation systems coupled with flame atomic absorption spectrometry (FAAS). Its performance characteristics were evaluated for trace copper determination in environmental samples. The on-line formed complex of metal with diethyldithiophosphate (DDPA) was sorbed on the PCTFE surface. Isobutyl methyl ketone (IBMK) at a flow rate of 2.8 mL min-1 was used to elute the analyte complex directly into the nebulizer-burner system of spectrophotometer. The proposed sorbent material reveal, excellent chemical and mechanical resistance, fast adsorption kinetics permitting the use of high sample flow rates up to 15 mL min-1 without loss of retention efficiency. For copper determination, with 90 s preconcentration time the sample frequency was 30 h-1, the enhancement factor was 250, which could be further improved by increasing the loading (preconcentration) time. The detection limit (3s) was c L = 0.07 μg L-1, and the precision (R.S.D.) was 1.8%, at the 2.0 μg L-1 Cu(II) level. For lead determination, the detection limit was c L = 2.7 μg L-1, and the precision (R.S.D.) 2.2%, at the 40.0 μg L-1 Pb(II) level. The accuracy of the developed method was evaluated by analyzing certified reference materials and by recovery measurements on spiked natural water samples

  5. High Dispersion Absorption-line Spectroscopy of AE Aqr

    Echevarria, J; Costero, R; Zharikov, S; Michel, R

    2008-01-01

    High-dispersion time-resolved spectroscopy of the unique magnetic cataclysmic variable AE Aqr is presented. A radial velocity analysis of the absorption lines yields K_2 = 168.7+/- 1 km/s. Substantial deviations of the radial velocity curve from a sinusoid are interpreted in terms of intensity variations over the secondary star's surface. A complex rotational velocity curve as a function of orbital phase is detected which has a modulation frequency of twice the orbital frequency, leading to an estimate of the binary inclination angle that is close to 70^o. The minimum and maximum rotational velocities are used to indirectly derive a mass ratio of q= 0.6 and a radial velocity semi-amplitude of the white dwarf of K_1 = 101+/-3 km/s. We present an atmospheric temperature indicator, based on the absorption line ratio of Fe I and Cr I lines, whose variation indicates that the secondary star varies from K0 to K4 as a function of orbital phase. The ephemeris of the system has been revised, using more than one thousa...

  6. Absorption lines and the radio structure of quasars

    High angular resolution radio observations at lambda6cm of 20 quasars are presented, all but two of which have been selected from a sample used by previous authors for a survey of absorption lines. The additional two, 1246-057 and 1333 + 286, are quasars with broad absorption lines and appear to be radio quiet. The radio structures for the entire sample of 66 sources of the previous authors are summarized and an investigation is made of whether the radio structure might provide clues on understanding the origin of the absorption lines in the range Zsub(em)-Zsub(ab) approx. 3000-18000 kms-1. The frequency of occurrence of absorption lines appears to be similar for both radio and optically selected quasars. (author)

  7. Determination of trace metal ions via on-line separation and preconcentration by means of chelating Sepharose beads in a sequential injection lab-on-valve (SI-LOV) system coupled to electrothermal atomic absorption spectrometric detection

    Long, Xiangbao; Hansen, Elo Harald; Miró, Manuel

    2005-01-01

    The analytical performance of an on-line sequential injection lab-on-valve (SI-LOV) system using chelating Sepharose beads as sorbent material for the determination of ultra trace levels of Cd(II), Pb(II) and Ni(II) by electrothermal atomic absorption spectrometry (ETAAS) is described and discussed...

  8. Monitoring the variability of intrinsic absorption lines in quasar spectra , ,

    We have monitored 12 intrinsic narrow absorption lines (NALs) in five quasars and seven mini-broad absorption lines (mini-BALs) in six quasars for a period of 4-12 yr (1-3.5 yr in the quasar rest-frame). We present the observational data and the conclusions that follow immediately from them, as a prelude to a more detailed analysis. We found clear variability in the equivalent widths (EWs) of the mini-BAL systems but no easily discernible changes in their profiles. We did not detect any variability in the NAL systems or in narrow components that are often located at the center of mini-BAL profiles. Variations in mini-BAL EWs are larger at longer time intervals, reminiscent of the trend seen in variable BALs. If we assume that the observed variations result from changes in the ionization state of the mini-BAL gas, we infer lower limits to the gas density ∼103-105 cm–3 and upper limits on the distance of the absorbers from the central engine of the order of a few kiloparsecs. Motivated by the observed variability properties, we suggest that mini-BALs can vary because of fluctuations of the ionizing continuum or changes in partial coverage while NALs can vary primarily because of changes in partial coverage.

  9. Reconstructing the intergalactic UV background with QSO absorption lines

    Fechner, Cora

    2011-01-01

    We present a new approach to constrain the spectral energy distribution of the intergalactic UV background observationally by studying metal absorption systems. We study single-component metal line systems exhibiting various well-measured species. Among the observed transitions at least two ratios of ionization stages from the same element are required, e.g. CIII/CIV and SiIII/SiIV. For each system photoionization models are constructed varying the spectrum of the ionizing radiation. The spectral energy distribution can then be constrained by comparing the models with the observed column density ratios. Extensive tests with artificial absorbers show that the spectrum of the ionizing radiation cannot be reconstructed unambiguously, but it is possible to constrain the main characteristics of the spectrum. Furthermore, the resulting physical parameters of the absorber, such as ionization parameter, metallicity, and relative abundances, may depend strongly on the adopted ionizing spectrum. Even in case of well-fi...

  10. Calculations of line absorption for the Voigt profile

    Kato, I.; Iwasaki, A.; Adachi, A.; Shimizu, T.

    1978-07-01

    Line-absorption calculations of the 388.9 nm triplet and the 501.6 nm singlet lines of helium have been performed for the Voigt profile. These results can be used to measure the absolute concentration of He 2s /sup 3/S and 2s /sup 1/S metastable atoms for the various discharge conditions by the reabosorption method.

  11. Broad Absorption Line Quasar catalogues with Supervised Neural Networks

    We have applied a Learning Vector Quantization (LVQ) algorithm to SDSS DR5 quasar spectra in order to create a large catalogue of broad absorption line quasars (BALQSOs). We first discuss the problems with BALQSO catalogues constructed using the conventional balnicity and/or absorption indices (BI and AI), and then describe the supervised LVQ network we have trained to recognise BALQSOs. The resulting BALQSO catalogue should be substantially more robust and complete than BI-or AI-based ones.

  12. The Redshifted Hydrogen Balmer and Metastable He I Absorption Line System in Mini-FeLoBAL Quasar SDSS J112526.12+002901.3: A Parsec Scale Accretion Inflow?

    Shi, Xi-Heng; Wang, Hui-Yuan; Zhang, Shao-Hua; Ji, Tuo; Liu, Wen-Juan; Zhou, Hong-Yan

    2016-01-01

    The accretion of interstellar medium onto the central super massive black holes is widely accepted as the source of the gigantic energy released by the active galactic nuclei. But few pieces of observational evidence have been confirmed directly demonstrating the existence of the inflows. The absorption line system in the spectra of quasar SDSS J112526.12+002901.3 presents an interesting example, in which the rarely detected hydrogen Balmer and metastable He I absorption lines are found redshifted to the quasar's rest frame along with the low-ionization metal absorption lines Mg II, Fe II, etc. The repeated SDSS spectroscopic observations suggest a transverse velocity smaller than the radial velocity. The motion of the absorbing medium is thus dominated by infall. The He I* lines present a powerful probe to the strength of ionizing flux, while the Balmer lines imply a dense environment. With the help of photoionization simulations, we find the absorbing medium is exposed to the radiation with ionization param...

  13. Potassium emission absorption system. Topical report 12

    Bauman, L.E.

    1995-04-01

    The Potassium Emission Absorption System is one of the advanced optical diagnostics developed at Mississippi State University to provide support for the demonstration of prototype-scale coal-fired combustion magnetohydrodynamic (MHD) electrical power generation. Intended for application in the upstream of an MHD flow, the system directly measures gas temperature and neutral potassium atom number density through spectroscopic emission absorption techniques. From these measurements the electron density can be inferred from a statistical equilibrium calculation and the electron conductivity in the MHD channel found by use of an electron mobility model. The instrument has been utilized for field test measurements on MHD facilities for almost a decade and has been proven to provide useful measurements as designed for MHD nozzle, channel, and diffuser test sections. The theory of the measurements, a system description, its capabilities, and field test measurement results are reported here. During the development and application of the instrument several technical issues arose which when addressed advanced the state of the art in emission absorption measurement. Studies of these issues are also reported here and include: two-wavelength measurements for particle-laden flows, potassium D-line far wing absorption coefficient, bias in emission absorption measurements arising from dirty windows and misalignments, non-coincident multiwavelength emission absorption sampling errors, and lineshape fitting for boundary layer flow profile information. Although developed for NLHD application, the instrument could be applied to any high temperature flow with a resonance line in the 300 to 800 nm range, for instance other types of flames, rocket plumes or low temperature plasmas.

  14. Constraining FeLoBAL outflows from absorption line variability

    McGraw, S M; Hamann, F W; Capellupo, D M; Gallagher, S C; Brandt, W N

    2015-01-01

    FeLoBALs are a rare class of quasar outflows with low-ionization broad absorption lines (BALs), large column densities, and potentially large kinetic energies that might be important for `feedback' to galaxy evolution. In order to probe the physical properties of these outflows, we conducted a multiple-epoch, absorption line variability study of 12 FeLoBAL quasars spanning a redshift range between 0.7 and 1.9 over rest frame time-scales of approximately 10 d to 7.6 yr. We detect absorption line variability with greater than 8 sigma confidence in 3 out of the 12 sources in our sample over time-scales of 0.6 to 7.6 yr. Variable wavelength intervals are associated with ground and excited state Fe II multiplets, the Mg II 2796, 2803 doublet, Mg I 2852, and excited state Ni II multiplets. The observed variability along with evidence of saturation in the absorption lines favors transverse motions of gas across the line of sight (LOS) as the preferred scenario, and allows us to constrain the outflow distance from th...

  15. Absorption Line Profile Recovery Based on TDLS and MEMS Micro-Mirror for Photoacoustic Gas Sensing

    LI Li; Norhana Arsad; George Stewart; Graham Thursby; Deepak Uttamchandani; Brian Culshaw; WANG Yi-ding

    2011-01-01

    A novel and efficient absorption line recovery technique is presented. A micro-electromechanical systems (MEMS) mirror driven by an electrothermal actuator is used to generate laser intensity modulation through the mirror reflection. Tunable diode laser spectroscopy (TDLS) and photoacoustic spectroscopy (PAS) are used to recover the target absorption line profile which is compared with the theoretical Voigt profile. The target gas is 0.01% acetylene (C2 H2 ) in a nitrogen host gas. The laser diode wavelength is swept across the P17 absorption line of acetylene at 1 535.4 nm by a current ramp, and an erbium-doped fibre amplifier (EDFA) is used to enhance the optical intensity and increase the signal-to-noise ratio (SNR). A SNR of about 35 is obtained with 100 mW laser power from the EDFA Good agreement is achieved between the experimental results and the theoretical simulation for the P17 absorption line profile.

  16. Hydrogen absorption line profiles of ionizing star clusters

    Angeles I. Díaz

    1988-01-01

    This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. Díaz, A.I. Hydrogen absorption line profiles of ionizing star clusters. Monthly Notices of the Royal Astronomical Society 231 (1988): 57-67 and Microfiche MN 231/1

  17. On-Line Wavelength Calibration of Pulsed Laser for CO2 Differential Absorption LIDAR

    Xiang, Chengzhi; Ma, Xin; Han, Ge; Liang, Ailin; Gong, Wei

    2016-06-01

    Differential absorption lidar (DIAL) remote sensing is a promising technology for atmospheric CO2 detection. However, stringent wavelength accuracy and stability are required in DIAL system. Accurate on-line wavelength calibration is a crucial procedure for retrieving atmospheric CO2 concentration using the DIAL, particularly when pulsed lasers are adopted in the system. Large fluctuations in the intensities of a pulsed laser pose a great challenge for accurate on-line wavelength calibration. In this paper, a wavelength calibration strategy based on multi-wavelength scanning (MWS) was proposed for accurate on-line wavelength calibration of a pulsed laser for CO2 detection. The MWS conducted segmented sampling across the CO2 absorption line with appropriate number of points and range of widths by using a tunable laser. Complete absorption line of CO2 can be obtained through a curve fitting. Then, the on-line wavelength can be easily found at the peak of the absorption line. Furthermore, another algorithm called the energy matching was introduced in the MWS to eliminate the backlash error of tunable lasers during the process of on-line wavelength calibration. Finally, a series of tests was conducted to elevate the calibration precision of MWS. Analysis of tests demonstrated that the MWS proposed in this paper could calibrate the on-line wavelength of pulsed laser accurately and steadily.

  18. VizieR Online Data Catalog: QSOs narrow absorption line variability (Hacker+, 2013)

    Hacker, T. L.; Brunner, R. J.; Lundgren, B. F.; York, D. G.

    2013-06-01

    Catalogues of 2,522 QAL systems and 33 variable NAL systems detected in SDSS DR7 quasars with repeat observations. The object identifiers, position coordinates, and plate-MJD-fibre designations are taken from the SpecObjAll table in the SDSS Catalogue Archive Server (CAS) while the quasar redshifts (zqso) are from Hewett & Wild (2010, Cat. J/MNRAS/405/2302). The absorption system redshift (zabs), system grade, and detected lines are outputs of the York et al. (2013, in. prep.) QAL detection pipeline. Some absorption lines are flagged based on alternate identifications (a), proximity of masked pixels (b), or questionable continuum fits (c). (3 data files).

  19. The sub-millimeter properties of broad absorption line quasars

    Willott, Chris J.; Rawlings, Steve; Grimes, Jennifer A.

    2003-01-01

    We have carried out the first systematic survey of the sub-millimeter properties of broad absorption line (BAL) quasars. 30 BAL quasars drawn from a homogeneously selected sample from the Sloan Digital Sky Survey at redshifts 2 3 sigma significance. The far-infrared luminosities of these quasars are > 10^{13} L_solar. There is no correlation of sub-millimeter flux with either the strength of the broad absorption feature or with absolute magnitude in our sample. We compare the sub-millimeter f...

  20. Calculations of line absorption for the Voigt profile and some specific lines of helium

    Kato, I.; Yonehara, A.

    1980-07-01

    Calculations of the line absorption for the 396.5- , 361.4- , 318.7- , 492.2- , 587.6- , and 447.1-nm lines of helium have been performed for the Voigt profile. These results can be used to measure the absolute concentration of helium metastable atoms and several other excited atoms by the reabsorption method.

  1. Non-Voigt Lyman-$\\alpha$ absorption line profiles

    Outram, P J; Theuns, T

    1999-01-01

    Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium, and the loss of a physical justification for Voigt profile fitting of the Lyman-alpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We develop a method to detect departures from Voigt profiles of the absorption lines in a statistical way and apply this method to simulated Lyman-alpha forest spectra, confirming that the profiles seen do statistically differ from Voigt profiles.

  2. Spectropolarimetry of Radio-Selected Broad Absorption Line Quasars

    DiPompeo, M. A.; Brotherton, M. S.; Becker, R. H.; Tran, H. D.; Gregg, M. D.; White, R L; Laurent-Muehleisen, S. A.

    2010-01-01

    We report spectropolarimetry of 30 radio-selected broad absorption line (BAL) quasars with the Keck Observatory, 25 from the sample of Becker et al. (2000). Both high and low-ionization BAL quasars are represented, with redshifts ranging from 0.5 to 2.5. The spectropolarimetric properties of radio-selected BAL quasars are very similar to those of radio-quiet BAL quasars: a sizeable fraction (20%) show large continuum polarization (2-10%) usually rising toward short wavelengths, emission lines...

  3. Polarization properties of broad absorption line QSOs : new statistical clues

    H. Lamy; Hutsemekers, Damien

    2004-01-01

    We report the results of several statistical tests performed on a large sample of 139 broad absorption line (BAL) QSOs with good quality optical spectra and/or optical polarization data. Correlations between ten optical indices and the polarization degree p[SUB]0[/SUB] are systematically searched for. We find six significant non-trivial correlations. In order to identify the most important correlations, we perform a principal component analysis with a sample of 30 BAL QSOs and eight quantitie...

  4. What sodium absorption lines tell us about type Ia supernovae

    Soker, Noam

    2014-01-01

    We propose that the sodium responsible for the variable Na I D absorption lines in some type Ia supernovae (SN Ia) originate from dust residing at ~1pc from the supernovae. In this Na-from-dust absorption (NaDA) model the process by which the SN Ia peak luminosity releases sodium from dust at ~1pc from the SN is similar to the processes by which solar radiation releases sodium from comet dust when comets approach a distance of ~1AU from the Sun. The dust grains are not sublimated but rather stay intact, and release sodium by photon-stimulated desorption (PSD; or photo-sputtering). We apply the NaDA model to SN 2006X and SN 2007le, and find it to comply better with the observed time variability of the Na I D absorption lines than the Na recombination model. The mass in the dusty shell of the NaDA model is much too high to be accounted for in the single-degenerate scenario for SN Ia. Therefore, the presence of variable Na I D lines in some SN Ia further weakens the already very problematic single-degenerate sce...

  5. Transient C IV Broad Absorption Lines in radio detected QSOs

    Vivek, M; Gupta, N

    2015-01-01

    We study the transient (i.e. emerging or disappearing) C IV broad absorption line (BAL) components in 50 radio detected QSOs using multi-epoch spectra available in Sloan Digital Sky Survey DR10. We report the detectionof 6 BALQSOs having at least one distinct transient C IV absorption component. Based on the structure function analysis of optical light curves, we suggest that the transient absorption is unlikely to be triggered by continuum variations. Transient absorption components usually have low C IV equivalent widths ( 10000 \\kms) and typically occur over rest-frame timescales > 800 days. The detection rate of transient C IV absorption seen in our sample is higher than that reported in the literature. Using a control sample of QSOs, we show that this difference is most likely due to the longer monitoring time-scale of sources in our sample while the effect of small number statistics cannot be ignored. Thus, in order to establish the role played by radio jets in driving the BAL outflows, we need a larger...

  6. Neutral atomic-carbon QSO absorption-line systems at z>1.5: Sample selection, HI content, reddening, and 2175 A extinction feature

    Ledoux, C; Petitjean, P; Srianand, R

    2015-01-01

    We present the results of a search for cold gas at high redshift along QSO lines-of-sight carried out without any a priori assumption on the neutral atomic-hydrogen (HI) content of the absorbers. To do this, we systematically looked for neutral-carbon (CI) 1560,1656 transition lines in low-resolution QSO spectra from the SDSS database. We built up a sample of 66 CI absorbers with redshifts 1.521 compared to systematic DLA surveys. We study empirical relations between W_r(CI), N(HI), E(B-V) and the strength of the 2175 A extinction feature, the latter being detected in about 30% of the CI absorbers. We show that the 2175 A feature is weak compared to Galactic lines-of-sight exhibiting the same amount of reddening. This is probably the consequence of current or past star formation in the vicinity of the CI systems. We also find that the strongest CI systems tend to have the largest amounts of dust and that the metallicity of the gas and its molecular fraction is likely to be high in a large number of cases.

  7. The JHU-SDSS Metal Absorption Line Catalog: Redshift Evolution and Properties of Mg II Absorbers

    Zhu, Guangtun; Ménard, Brice

    2013-06-01

    We present a generic and fully automatic method aimed at detecting absorption lines in the spectra of astronomical objects. The algorithm estimates the source continuum flux using a dimensionality reduction technique and nonnegative matrix factorization, and then detects and identifies metal absorption lines. We apply it to a sample of ~105 quasar spectra from the Sloan Digital Sky Survey and compile a sample of ~40,000 Mg II- and Fe II-absorber systems, spanning the redshift range 0.4 history over 0.4 < z < 5.5 (the entire redshift range covered by observations), suggesting a physical link between these two quantities.

  8. Time variations of narrow absorption lines in high resolution quasar spectra

    Boissé, P; Prochaska, J X; Péroux, C; York, D G

    2015-01-01

    Aims. We have searched for temporal variations of narrow absorption lines in high resolution quasar spectra. A sample of 5 distant sources have been assembled, for which 2 spectra - VLT/UVES or Keck/HIRES - taken several years apart are available. Methods. We first investigate under which conditions variations in absorption line profiles can be detected reliably from high resolution spectra, and discuss the implications of changes in terms of small-scale structure within the intervening gas or intrinsic origin. The targets selected allow us to investigate the time behavior of a broad variety of absorption line systems, sampling diverse environments: the vicinity of active nuclei, galaxy halos, molecular-rich galaxy disks associated with damped Lya systems, as well as neutral gas within our own Galaxy. Results. Absorption lines from MgII, FeII or proxy species with lines of lower opacity tracing the same kind of gas appear to be remarkably stable (1 sigma upper limits as low as 10 % for some components on scal...

  9. Polar Outflows in Six Broad Absorption Line Quasars

    Zhou, Hongyan; Wang, Tinggui; Wang, Huiyuan; Wang, Junxian; Yuan, Weimin; Lu, Yu

    2005-01-01

    Using the radio observations by FIRST and NVSS, we build a sample of 151 radio variable quasars selected from the Sloan Digital Sky Survey Data Release 3 (SDSS DR3). Six (probably another two) among them are classified as broad absorption line (BAL) quasars, with radio flux variations of a few 10 percent within 1.5-5 years. Such large amplitudes of the variations imply brightness temperatures much higher than the inverse Compton limits (10$^{12}$ K) in all the BAL quasars, suggesting the pres...

  10. On The Formation Of Multiple Absorption Troughs In Broad Absorption Line QSOs

    Pereyra, Nicolas A

    2013-01-01

    We present theoretical CIV 1548,1550 absorption line profiles for QSOs calculated assuming the accretion disk wind (ADW) scenario. The results suggest that the multiple absorption troughs seen in many QSOs may be due to the discontinuities in the ion balance of the wind (caused by X-rays), rather than discontinuities in the density/velocity structure. The profiles are calculated from a 2.5D time-dependent hydrodynamic simulation of a line-driven disk wind for a typical QSO black hole mass, a typical QSO luminosity, and for a standard Shakura-Sunyaev disk. We include the effects of ionizing X-rays originating from within the inner disk radius by assuming that the wind is shielded from the X-rays from a certain viewing angle up to 90o ("edge on"). In the shielded region we assume constant ionization equilibrium, and thus constant line-force parameters. In the non-shielded region we assume that both the line-force and the C+3 populations are nonexistent. The model, at viewing angles close to the angle that separ...

  11. Application of Fiber Bragg Grating for Determining Positions of Gas Absorption Lines

    HAN Wennian; WANG Yan; MA Feng; LIU Kun; JIA Dagong; LIU Tiegen; ZHANG Hongxia

    2010-01-01

    Fiber Bragg grating(FBG)is used as a wavelength reference device to calibrate the position of gas absorption peak in the intracavity absorption gas sensor(ICAGS)based on erbium-doped fiberring laser.This system can detect both the reflectance spectrum of FBGs and absorption spectrum of measured gas during a single wavelength sweeping process by linearly varying the driving voltage of optic filter.The voltages corresponding to center wavelength positions of four FBGs in the spectrum are determined through Gaussian peak fitting.Then,the wavelengths of gas absorption lines are deduced from the correspondence between driving voltage and wavelength obtained by quadratic curve fitting.The maximum error of wavelength of acetylene absorption lines between experimental results and those from HITRAN database is 0.106 nm and the resolving accuracy of two adjacent absorption lines is about93.593%.By using this method,ICAGS can theoretically recognize the measured gas type and monitor multi-gas components.

  12. Identification of Metal Absorption Lines on Quasar Spectra of SDSS DR9

    Cai-Juan Pan; Cheng-Yu Su; Mu-Sheng Li; Wei-Rong Huang

    2014-09-01

    Absorption lines are an important tool for probing the gas in the Universe. Our group aim to identify the metal absorption lines imprinted on the quasar spectra of the BOSS. In this work, we show the metal absorption lines identified in the spectrum of SDSS J160032.95+323638.7.

  13. HI Absorption Lines Detected from the Arecibo Legacy Fast ALFA Survey Data

    Zhong-zu, Wu; Martha P, Haynes; Riccardo, Giovanelli; Ming, Zhu; Ru-rong, Chen

    2015-10-01

    We present some preliminary results of an on-going study of HI 21-cm absorption lines based on the 40% survey data released by the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). (1) Ten HI candidate absorbers have been detected. Five of them are previously published in the literature, and the rest of them are new detections that need further confirmation. (2) For those sources with no detected absorptions, we have calculated the upper limit of their foreground HI column density NHI. The statistical result of the NHI distribution indicates that the ratio Ts/f between the averaged spin temperature and coverage factor for DLAs (the damped Lyα systems) might be larger than 500 K. The radio frequency interference (RFI) and standing wave are the main factors affecting the detection of HI absorption lines, which have been analyzed and discussed as well in order to find a method of solution. Our study can serve as a pathfinder for the future large-scale search of HI 21-cm absorption lines using the Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST), which is an Arecibo-type radio telescope currently under construction in China with greatly increased sensitivity, bandwidth, and observational sky area. As prospects, we have discussed two types of observational studies of HI absorption lines toward extragalactic sources using the FAST telescope.

  14. Ultraviolet observations of interstellar absorption lines toward SN 1987A

    Savage, Blair D.; Jenkins, Edward B.; Joseph, Charles L.; De Boer, Klass S.

    1989-01-01

    High-dispersion IUE echelle spectra of SN 1987A were averaged in order to obtain UV absorption-line profiles of the highest possible quality in the direction of SN 1987A. The profiles for Si IV and C IV are quite similar and have much less structure than the Al III profile. On relating column densities, while the C IV and Si IV ratio is relatively constant over the 0-100 km/s velocity range, the C IV to Al III and Si IV to Al III ratios vary by nearly a factor of 10. This suggests that the C IV and Si IV along this sight line in the Galaxy and its halo may have a common origin which differs from that for Al III.

  15. Narrow absorption lines with two observations of Sloan Digital Sky Survey

    Chen, Zhi-Fu; Chen, Yan-Mei; Cao, Yue

    2015-01-01

    We assemble 3524 quasars from Sloan Digital Sky Survey (SDSS) with repeated observations to search for variations of narrow C IV1548,1551 and Mg II2796,2803 absorption doublets in spectral regions shortward of 7000 Ang at the observed frame, which corresponds to time-scales of about 150 ~ 2643 days at quasar rest frame. In these quasar spectra, we detect 3580 C IV absorption systems with z_{abs} = 1.5188 ~ 3.5212, and 1809 Mg II absorption systems with z_{abs} = 0.3948 ~ 1.7167. In term of the absorber velocity (beta) distribution at quasar rest frame, we find a substantial number of C IV absorbers with beta4sigma for lambda2796 lines and >3sigma for lambda2803 lines.

  16. The influence of radio-galaxy activity on X-ray absorption lines from the intracluster medium

    Koeckert, F; Koeckert, Franziska; Reynolds, Christopher S.

    2006-01-01

    We present an investigation of the X-ray absorption features predicted by hydrodynamic simulations of radio galaxies interacting with the intracluster medium (ICM) of their host galaxy clusters. We show how these absorption lines can be used as a new diagnostic for the radio-galaxy/ICM interactions. Such interactions have been observed in numerous systems by ROSAT, CHANDRA and XMM-NEWTON, and understanding them has implications for AGN feedback and galaxy formation. Starting from the hydrodynamic simulations of Reynolds, Heinz & Begelman (2002), we calculate the properties of the highly ionized iron and oxygen lines (seen in absorption against the central active galactic nucleus; AGN), predicting line shapes, equivalent widths, column densities and velocity shifts. The main effect of the jet on the absorption lines is a reduction of the line strength from that of the quiescent ICM and the introduction of some velocity structure in the line profile. We investigate whether these features are detectable with...

  17. A Variable PV Broad Absorption Line and Quasar Outflow Energetics

    Capellupo, Daniel M; Barlow, Tom A

    2014-01-01

    Broad absorption lines (BALs) in quasar spectra identify high velocity outflows that might exist in all quasars and could play a major role in feedback to galaxy evolution. The viability of BAL outflows as a feedback mechanism depends on their kinetic energies, as derived from the outflow velocities, column densities, and distances from the central quasar. We estimate these quantities for the quasar, Q1413+1143 (redshift $z_e = 2.56$), aided by the first detection of PV $\\lambda\\lambda$1118,1128 BAL variability in a quasar. In particular, PV absorption at velocities where the CIV trough does not reach zero intensity implies that the CIV BAL is saturated and the absorber only partially covers the background continuum source (with characteristic size 22.3 (cm^-2). Variability in the PV and saturated CIV BALs strongly disfavors changes in the ionization as the cause of the BAL variability, but supports models with high-column density BAL clouds moving across our lines of sight. The observed variability time of ...

  18. Strong Clustering of High-Redshift Lyman-alpha Forest Absorption Systems

    Fernandez-Soto, A.; Lanzetta, K. M.; Barcons, X.; Carswell, R. F.; Webb, J. K.; Yahil, A.

    1996-01-01

    We use new observations of very weak CIV absorption lines associated with high-redshift Lyman-alpha absorption systems to measure the high-redshift Lyman-alpha line two-point correlation function (TPCF). These very weak CIV absorption lines trace small-scale velocity structure that cannot be resolved by Lyman-alpha absorption lines. We find that (1) high-redshift Lyman-alpha absorption systems with N(HI) > 3.10^14 cm^{-2} are strongly clustered in redshift, (2) previous measurements of the Ly...

  19. The Connection Between Galaxies and Intergalactic Absorption Lines at Redshift 2

    Adelberger, K L; Steidel, C C; Pettini, M; Erb, D K; Reddy, N A

    2005-01-01

    Absorption-line spectroscopy of 23 background QSOs and numerous background galaxies has let us measure the spatial distribution of metals and neutral hydrogen around 1044 UV-selected galaxies at redshifts 1.8260 km/s) and produces very strong absorption lines (N_CIV >> 10^14 cm^-2) in the spectra of background objects. Absorption with an average column density of N_CIV ~ 10^14 cm^-2 extends to 80 kpc, a radius large enough to imply that most strong intergalactic CIV absorption is associated with star-forming galaxies like those in our sample. We find that the galaxy-CIV cross-correlation length increases with CIV column density and is similar to the galaxy-galaxy length (r_0 ~ 4 h^-1 Mpc) for N_CIV > 10^12.5 cm^-2. Distortions in the redshift-space galaxy-CIV correlation function on small scales may imply that some of the CIV systems have large peculiar velocities. Four of the five detected OVI absorption systems in our sample lie within 400 proper kpc of a known galaxy. Strong Lyman-a absorption is produced ...

  20. COS OBSERVATIONS OF METAL LINE AND BROAD LYMAN-α ABSORPTION IN THE MULTI-PHASE O VI AND Ne VIII SYSTEM AT z = 0.20701 TOWARD HE 0226-4110

    Observations of the QSO HE 0226-4110 (zem = 0.495) with the Cosmic Origins Spectrograph (COS) from 1134 to 1796 Å with a resolution of ∼17 km s–1 and signal-to-noise ratio (S/N) per resolution element of 20-40 are used to study the multi-phase absorption system at z = 0.20701 containing O VI and Ne VIII. The system was previously studied with lower S/N observations with Far-Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS). The COS observations provide more reliable measures of the H I and metal lines present in the system and reveal the clear presence of broad Lyα (BLA) absorption with b = 72(+13, –6) km s–1 and log N(H I) = 13.87 ± 0.08. Detecting BLAs associated with warm gas absorbers is crucial for determining the temperature, metallicity, and total baryonic content of the absorbers. The BLA is probably recording the trace amount of thermally broadened H I in the collisionally ionized plasma with log T ∼ 5.7 that also produces the O VI and Ne VIII absorption. The total hydrogen column in the collisionally ionized gas, log N(H) ∼ 20.1, exceeds that in the cooler photoionized gas in the system by a factor of ∼22. The oxygen abundance in the collisionally ionized gas is [O/H] = –0.89 ± 0.08 ± 0.07. The absorber probably occurs in the circumgalactic environment (halo) of a foreground L = 0.25L* disk galaxy with an impact parameter of 109 h70–1 kpc identified by Mulchaey and Chen.

  1. COS OBSERVATIONS OF METAL LINE AND BROAD LYMAN-{alpha} ABSORPTION IN THE MULTI-PHASE O VI AND Ne VIII SYSTEM AT z = 0.20701 TOWARD HE 0226-4110

    Savage, B. D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Lehner, N. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Narayanan, A. [Indian Institute of Space Science and Technology, Thiruvananthapuram 695547, Kerala (India)

    2011-12-20

    Observations of the QSO HE 0226-4110 (z{sub em} = 0.495) with the Cosmic Origins Spectrograph (COS) from 1134 to 1796 A with a resolution of {approx}17 km s{sup -1} and signal-to-noise ratio (S/N) per resolution element of 20-40 are used to study the multi-phase absorption system at z = 0.20701 containing O VI and Ne VIII. The system was previously studied with lower S/N observations with Far-Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS). The COS observations provide more reliable measures of the H I and metal lines present in the system and reveal the clear presence of broad Ly{alpha} (BLA) absorption with b = 72(+13, -6) km s{sup -1} and log N(H I) = 13.87 {+-} 0.08. Detecting BLAs associated with warm gas absorbers is crucial for determining the temperature, metallicity, and total baryonic content of the absorbers. The BLA is probably recording the trace amount of thermally broadened H I in the collisionally ionized plasma with log T {approx} 5.7 that also produces the O VI and Ne VIII absorption. The total hydrogen column in the collisionally ionized gas, log N(H) {approx} 20.1, exceeds that in the cooler photoionized gas in the system by a factor of {approx}22. The oxygen abundance in the collisionally ionized gas is [O/H] = -0.89 {+-} 0.08 {+-} 0.07. The absorber probably occurs in the circumgalactic environment (halo) of a foreground L = 0.25L{sub *} disk galaxy with an impact parameter of 109 h{sub 70}{sup -1} kpc identified by Mulchaey and Chen.

  2. On the Absorption of X-ray Bright Broad Absorption Line Quasars

    Giustini, Margherita; Vignali, Cristian

    2008-01-01

    Most X-ray studies of BALQSOs found significant (N_H~10^{22-24} cm^{-2}) intrinsic column densities of gas absorbing an underlying typical power-law continuum emission, in agreement with expectations from radiatively driven accretion disk wind models. However, direct spectral analysis was performed only on a limited number of bright sources. We investigate the X-ray emission of a large BALQSO sample at medium to high redshift (0.8 ~ 5 x 10^{22} cm^{-2}) even including the faintest sources analyzed through hardness ratio analysis. The mean photon index is Gamma~1.9, with no significant evolution with redshift. The alpha_ox are typical of radio-quiet broad line AGN, in contrast with the known (from previous X-ray studies) ``soft X-ray weakness'' of BALQSOs and in agreement with the lack of X-ray absorption. We found the low-Absorption Index (AI) subsample to host the lowest X-ray absorbing column densities of the entire sample. X-ray selected BALQSOs show lower X-ray absorption than purely optically selec ted o...

  3. Radio Structures of Compact Quasars with Broad Absorption Lines

    Kunert-Bajraszewska, Magdalena; Gawroński, Marcin P.

    2010-05-01

    Broad absorption lines (BALs), seen in a small fraction of both the radio-quiet and radio-loud quasar populations, are probably caused by the outflow of gas with high velocities and are part of the accretion process. The presence of BALs is due to a geometrical effect and/or it is connected with the quasar evolution. Using the final release of FIRST survey combined with a catalog of BAL QSOs from SDSS/DR3, we have constructed a new sample of compact radio-loud BAL QSOs, which constitutes the majority of radio-loud BAL QSOs. The main goal of this project is to study the origin of BALs by analysis of the BAL QSOs radio morphology, orientation, and jet evolution using the European VLBI Network (EVN) at 1.6 GHz and the Very Long Baseline Array (VLBA) at 5 and 8.4 GHz.

  4. Quasar Outflow Constraints using Broad Absorption Line Variability Studies

    McGraw, Sean; Shields, Joseph C.; Hamann, Fred; Capellupo, Daniel M.; Gallagher, Sarah; Brandt, W. Niel; Herbst, Hanna

    2016-01-01

    Quasar outflows are plausible candidates for AGN feedback processes influencing the host galaxy and may explain the established correlations between the supermassive black hole (SMBH) and the surrounding bulge. In order to better understand feedback and the physical conditions of the outflowing gas, observational constraints on absorber kinematics and energetics are needed. We are utilizing multiple epoch, rest frame UV quasar spectra to establish limits on outflow locations and total column densities for the purpose of estimating wind kinetic energies and momenta. We are also investigating the variability patterns of broad absorption lines (BALs) and mini-BALs across a range of ionization states to probe underlying connections between the various classes of absorbers. This work employs observations from the Sloan Digital Sky Survey, Hobby Eberly Telescope, and MDM observatory. We detect BAL variability in 3 out of 12 FeLoBAL quasars over multiple year timescales and conclude that the variable absorbers lie within tens of parsecs of the SMBH based on interpretations of the Fe II and Mg II BALS. We also measure significant BAL changes across daily to yearly timescales in a sample of 71 quasars with plausible detections of the P V 1117,1128 BAL. Detecting phosphorus in absorption is notable because it traces high column density outflows and is therefore relevant for studying AGN feedback. Constraints on outflow energetics and other selected results will be presented.

  5. Peculiar Broad Absorption Line Quasars found in DPOSS

    Brunner, R J; Djorgovski, S G; Gal, R R; Mahabal, A A; Lopes, P A A; De Carvalho, R R; Odewahn, S C; Castro, S; Thompson, D; Chaffee, F; Darling, J; Desai, V; Brunner, Robert J.; Hall, Patrick B.

    2003-01-01

    With the recent release of large (i.e., > hundred million objects), well-calibrated photometric surveys, such as DPOSS, 2MASS, and SDSS, spectroscopic identification of important targets is no longer a simple issue. In order to enhance the returns from a spectroscopic survey, candidate sources are often preferentially selected to be of interest, such as brown dwarfs or high redshift quasars. This approach, while useful for targeted projects, risks missing new or unusual species. We have, as a result, taken the alternative path of spectroscopically identifying interesting sources with the sole criterion being that they are in low density areas of the g - r and r - i color-space defined by the DPOSS survey. In this paper, we present three peculiar broad absorption line quasars that were discovered during this spectroscopic survey, demonstrating the efficacy of this approach. PSS J0052+2405 is an Iron LoBAL quasar at a redshift z = 2.4512 with very broad absorption from many species. PSS J0141+3334 is a reddened...

  6. Broad Absorption Line Variability in Radio-Loud Quasars

    Welling, C A; Brandt, W N; Capellupo, D M; Gibson, R R

    2014-01-01

    We investigate C IV broad absorption line (BAL) variability within a sample of 46 radio-loud quasars (RLQs), selected from SDSS/FIRST data to include both core-dominated (39) and lobe-dominated (7) objects. The sample consists primarily of high-ionization BAL quasars, and a substantial fraction have large BAL velocities or equivalent widths; their radio luminosities and radio-loudness values span ~2.5 orders of magnitude. We have obtained 34 new Hobby-Eberly Telescope (HET) spectra of 28 BAL RLQs to compare to earlier SDSS data, and we also incorporate archival coverage (primarily dual-epoch SDSS) for a total set of 78 pairs of equivalent width measurements for 46 BAL RLQs, probing rest-frame timescales of ~80-6000 d (median 500 d). In general, only modest changes in the depths of segments of absorption troughs are observed, akin to those seen in prior studies of BAL RQQs. Also similar to previous findings for RQQs, the RLQs studied here are more likely to display BAL variability on longer rest-frame timescal...

  7. Outflow and hot dust emission in broad absorption line quasars

    We have investigated a sample of 2099 broad absorption line (BAL) quasars with z = 1.7-2.2 built from the Sloan Digital Sky Survey Data Release Seven and the Wide-field Infrared Survey. This sample is collected from two BAL quasar samples in the literature and is refined by our new algorithm. Correlations of outflow velocity and strength with a hot dust indicator (βNIR) and other quasar physical parameters—such as an Eddington ratio, luminosity, and a UV continuum slope—are explored in order to figure out which parameters drive outflows. Here βNIR is the near-infrared continuum slope, which is a good indicator of the amount of hot dust emission relative to the accretion disk emission. We confirm previous findings that outflow properties moderately or weakly depend on the Eddington ratio, UV slope, and luminosity. For the first time, we report moderate and significant correlations of outflow strength and velocity with βNIR in BAL quasars. It is consistent with the behavior of blueshifted broad emission lines in non-BAL quasars. The statistical analysis and composite spectra study both reveal that outflow strength and velocity are more strongly correlated with βNIR than the Eddington ratio, luminosity, and UV slope. In particular, the composites show that the entire C IV absorption profile shifts blueward and broadens as βNIR increases, while the Eddington ratio and UV slope only affect the high and low velocity part of outflows, respectively. We discuss several potential processes and suggest that the dusty outflow scenario, i.e., that dust is intrinsic to outflows and may contribute to the outflow acceleration, is most likely.

  8. The intensity calculation of the gas absorption line by multi-line Voigt fitting

    ZHOU Meng-ran; LI Zhen-bi; ZHONG Ming-yu; HE Gang

    2008-01-01

    Adopted the distribution feedback type (DFB) laser to measure the coal mine gas methane, according to the methane located 1.6 lain nearby 2v3 with a R9 direct ab-sorption spectrum, attraction wire intensity of each line was calculated through the multi-line Voigt fitting. The experimental result indicates that in the obtained four attraction recover of wire, the maximum deviation is 2.7%, and the minimum deviation is 0.02%, other results are all in experimental error scope. This research method may apply in the spectrum survey methane gas density, it has characteristics including high precision, strong selectivity, fast response and so on.

  9. Correction of the self-absorption for reversed spectral lines: application to two resonance lines of neutral aluminium

    A new method for the correction of reversed spectral lines, in consequence of self-absorption, is proposed in this article. This method was applied to two resonance lines of neutral aluminium (Al I) obtained by a laser pulse on an aluminium solid placed in air. Several spectra of these lines were corrected for various delays after the laser pulse. The evolution of several parameters of these lines was computed as a function of this delay after the correction of self-absorption

  10. Line absorption of He-like triplet lines by Li-like ions. Caveats of using line ratios of triplets for plasma diagnostics

    Mehdipour, M.; Kaastra, J. S.; Raassen, A. J. J.

    2015-01-01

    He-like ions produce distinctive series of triplet lines under various astrophysical conditions. However, this emission can be affected by line absorption from Li-like ions in the same medium. We investigate this absorption of He-like triplets and present the implications for diagnostics of plasmas in photoionisation equilibrium using the line ratios of the triplets. Our computations were carried out for the O VI and Fe XXIV absorption of the O VII and Fe XXV triplet emission lines, respectiv...

  11. The Physical Nature of Polar Broad Absorption Line Quasars

    Ghost, Kajal; Punsly, Brian

    2007-01-01

    It has been shown based on radio variability arguments that some BALQSOs (broad absorption line quasars) are viewed along the polar axis (o rthogonal to accretion disk) in the recent article of Zhou et a. Thes e arguments are based on the brightness temperature, T(sub b) exceedi ng 10(exp 12) K which leads to the well-known inverse Compton catastr ophe unless the radio jet is relativistic and is viewed along its axi s. In this letter, we expand the Zhou et al sample of polar BALQSOs u sing their techniques applied to SDSS DR5. In the process, we clarify a mistake in their calculation of brightness temperature. The expanded sample of high T(sub b) BALQSOS, has an inordinately large fraction of LoBALQSOs (low ionization BALQSOs). We consider this an important clue to understanding the nature of the polar BALQSOs. This is expec ted in the polar BALQSO analytical/numerical models of Punsly that pr edicted that LoBALQSOs occur when the line of sight is very close to the polar axis, where the outflow density is the highest.

  12. A new analysis of fine-structure constant measurements and modelling errors from quasar absorption lines

    Wilczynska, Michael R.; Webb, John K.; King, Julian A.; Murphy, Michael T.; Bainbridge, Matthew B.; Flambaum, Victor V.

    2015-12-01

    We present an analysis of 23 absorption systems along the lines of sight towards 18 quasars in the redshift range of 0.4 ≤ zabs ≤ 2.3 observed on the Very Large Telescope (VLT) using the Ultraviolet and Visual Echelle Spectrograph (UVES). Considering both statistical and systematic error contributions we find a robust estimate of the weighted mean deviation of the fine-structure constant from its current, laboratory value of Δα/α = (0.22 ± 0.23) × 10-5, consistent with the dipole variation reported in Webb et al. and King et al. This paper also examines modelling methodologies and systematic effects. In particular, we focus on the consequences of fitting quasar absorption systems with too few absorbing components and of selectively fitting only the stronger components in an absorption complex. We show that using insufficient continuum regions around an absorption complex causes a significant increase in the scatter of a sample of Δα/α measurements, thus unnecessarily reducing the overall precision. We further show that fitting absorption systems with too few velocity components also results in a significant increase in the scatter of Δα/α measurements, and in addition causes Δα/α error estimates to be systematically underestimated. These results thus identify some of the potential pitfalls in analysis techniques and provide a guide for future analyses.

  13. The impacts of temperature on the absorption spectral lines of carbon monoxide

    In order to study the change of temperature on the effects of carbon monoxide absorption spectral lines, first of all proceed from the principle of absorption spectra, using theoretical analysis method, and the transmission and absorption database of the high-resolution molecular educed the carbon monoxide absorption spectrum intensity of spectral lines, integrated widening line type function and absorption coefficient concerned with temperature, then we got the change curve between carbon monoxide absorption spectrum intensity of spectral lines, integrated widening line type function and absorption coefficient with temperature by the numerical simulation of MATLAB, and analyzed and discussed the relationship between the temperature and them. The results showed that the temperature on the effects of carbon monoxide absorption spectral lines, especially on an Integrated widening line type function is complex, and different laser frequencies will also affect the relationship of the line type function and the absorption coefficient change with temperature, which has important reference value for the absorption and measurement of carbon in practical application.

  14. Tunable diode laser absorption spectroscopy-based tomography system for on-line monitoring of two-dimensional distributions of temperature and H{sub 2}O mole fraction

    Xu, Lijun, E-mail: lijunxu@buaa.edu.cn; Liu, Chang; Jing, Wenyang; Cao, Zhang [School of Instrument Science and Opto-Electronic Engineering, Beihang University, Beijing 100191 (China); Ministry of Education’s Key Laboratory of Precision Opto-Mechatronics Technology, Beijing 100191 (China); Xue, Xin; Lin, Yuzhen [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China)

    2016-01-15

    To monitor two-dimensional (2D) distributions of temperature and H{sub 2}O mole fraction, an on-line tomography system based on tunable diode laser absorption spectroscopy (TDLAS) was developed. To the best of the authors’ knowledge, this is the first report on a multi-view TDLAS-based system for simultaneous tomographic visualization of temperature and H{sub 2}O mole fraction in real time. The system consists of two distributed feedback (DFB) laser diodes, a tomographic sensor, electronic circuits, and a computer. The central frequencies of the two DFB laser diodes are at 7444.36 cm{sup −1} (1343.3 nm) and 7185.6 cm{sup −1} (1391.67 nm), respectively. The tomographic sensor is used to generate fan-beam illumination from five views and to produce 60 ray measurements. The electronic circuits not only provide stable temperature and precise current controlling signals for the laser diodes but also can accurately sample the transmitted laser intensities and extract integrated absorbances in real time. Finally, the integrated absorbances are transferred to the computer, in which the 2D distributions of temperature and H{sub 2}O mole fraction are reconstructed by using a modified Landweber algorithm. In the experiments, the TDLAS-based tomography system was validated by using asymmetric premixed flames with fixed and time-varying equivalent ratios, respectively. The results demonstrate that the system is able to reconstruct the profiles of the 2D distributions of temperature and H{sub 2}O mole fraction of the flame and effectively capture the dynamics of the combustion process, which exhibits good potential for flame monitoring and on-line combustion diagnosis.

  15. Interstellar absorption in the Mg II resonance line k2 and h2 emissions

    Boehm-Vitense, E.

    1981-01-01

    High-resolution (0.2 A) IUE spectra for the long wavelength range (1800-3000 A) have been studied. It is shown that narrow interstellar Mg II lines are seen in the center of the k2 and h2 emissions from nearby stars with large rotational velocities. For all observed stars, the radial velocity of the central k3 absorption component in the rest system of the star is strongly correlated with the mirror image of the radial velocity of the stars; this shows that a major fraction if not all of the k3 absorption is due to interstellar absorption in the solar neighborhood. The violet to red asymmetry of the k2 emission also correlates with the radial velocities of the star; this shows that the shift of k3 is due to the velocity shift of the local interstellar cloud with respect to the star.

  16. Tracing Inflows and Outflows with Absorption Lines in Circumgalactic Gas

    Ford, Amanda Brady; Oppenheimer, Benjamin D; Katz, Neal; Kollmeier, Juna A; Thompson, Robert; Weinberg, David H

    2013-01-01

    We examine how HI and metal absorption lines within low-redshift galaxy halos trace the dynamical state of circumgalactic gas, using cosmological hydrodynamic simulations that include a well-vetted heuristic model for galactic outflows. We categorize inflowing, outflowing, and ambient gas based on its history and fate as tracked in our simulation. Following our earlier work showing that the ionisation level of absorbers was a primary factor in determining the physical conditions of absorbing gas, we show here that it is also a governing factor for its dynamical state. Low-ionisation metal absorbers (e.g. MgII) tend to arise in gas that will fall onto galaxies within several Gyr, while high-ionisation metal absorbers (e.g. OVI) generally trace material that was deposited by outflows many Gyr ago. Inflowing gas is dominated by enriched material that was previously ejected in an outflow, hence accretion at low redshifts is typically substantially enriched. Recycling wind material is preferentially found closer t...

  17. Absolute absorption on the potassium D lines: theory and experiment

    Hanley, Ryan K.; Gregory, Philip D.; Hughes, Ifan G.; Cornish, Simon L.

    2015-10-01

    We present a detailed study of the absolute Doppler-broadened absorption of a probe beam scanned across the potassium D lines in a thermal vapour. Spectra using a weak probe were measured on the 4S \\to 4P transition and compared to the theoretical model of the electric susceptibility detailed by Zentile et al (2015 Comput. Phys. Commun. 189 162-74) in the code named ElecSus. Comparisons were also made on the 4S \\to 5P transition with an adapted version of ElecSus. This is the first experimental test of ElecSus on an atom with a ground state hyperfine splitting smaller than that of the Doppler width. An excellent agreement was found between ElecSus and experimental measurements at a variety of temperatures with rms errors ˜ {10}-3. We have also demonstrated the use of ElecSus as an atomic vapour thermometry tool, and present a possible new measurement technique of transition decay rates which we predict to have a precision of ˜3 {kHz}.

  18. X-Ray Continua of Broad Absorption Line Quasars

    Mathur, S.

    1999-01-01

    The targets for this program, PG1416-129 and LBQS 2212-1759 were known to be Broad Absorption Line Quasars (BALQSOs). BALQSOs are highly absorbed in soft X-rays. Good high energy response of Rossi-XTE made them ideal targets for observation. We observed LBQS 2212-1759 with PCA. We have now analyzed the data and found that the source was not detected. Since our target was expected to be faint, reliable estimate of background was very important. With the release of new FTOOLS (version 4.1) we were able to do so. We also analyzed a well known bright object and verified our results with the published data. This gave us confidence in the non-detection of our target LBQS 2212-1759. We are currently investigating the implications of this non-detection. Due to some scheduling problems, our second target PG1416-129 was not observed in A01. It was observed on 06/26/98. This target was detected with RXTE. We are now working on the spectral analysis with XSPEC.

  19. An ALMA Early Science survey of molecular absorption lines toward PKS1830-211 -- Analysis of the absorption profiles

    Muller, S; Guelin, M; Gerin, M; Aalto, S; Beelen, A; Black, J H; Curran, S J; Darling, J; Dinh-V-Trung,; Garcia-Burillo, S; Henkel, C; Horellou, C; Martin, S; Marti-Vidal, I; Menten, K M; Murphy, M T; Ott, J; Wiklind, T; Zwaan, M A

    2014-01-01

    We present the first results of an ALMA spectral survey of strong absorption lines for common interstellar species in the z=0.89 molecular absorber toward the lensed blazar PKS1830-211. The dataset brings essential information on the structure and composition of the absorbing gas in the foreground galaxy. In particular, we find absorption over large velocity intervals (gtrsim 100 km/s) toward both lensed images of the blazar. This suggests either that the galaxy inclination is intermediate and that we sample velocity gradients or streaming motions in the disk plane, that the molecular gas has a large vertical distribution or extraplanar components, or that the absorber is not a simple spiral galaxy but might be a merger system. The number of detected species is now reaching a total of 42 different species plus 14 different rare isotopologues toward the SW image, and 14 species toward the NE line-of-sight. The abundances of CH, H2O, HCO+, HCN, and NH3 relative to H2 are found to be comparable to those in the G...

  20. Wavelength Locking to CO2 Absorption Line-Center for 2-Micron Pulsed IPDA Lidar Application

    Refaat, Tamer F.; Petros, Mulugeta; Antill, Charles W.; Singh, Upendra N.; Yu, Jirong

    2016-01-01

    An airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar is currently under development at NASA Langley Research Center (LaRC). This IPDA lidar system targets both atmospheric carbon dioxide (CO2) and water vapor (H2O) column measurements. Independent wavelength control of each of the transmitted laser pulses is a key feature for the success of this instrument. The wavelength control unit provides switching, tuning and locking for each pulse in reference to a 2-micron CW (Continuous Wave) laser source locked to CO2 line-center. Targeting the CO2 R30 line center, at 2050.967 nanometers, a wavelength locking unit has been integrated using semiconductor laser diode. The CO2 center-line locking unit includes a laser diode current driver, temperature controller, center-line locking controller and CO2 absorption cell. This paper presents the CO2 center-line locking unit architecture, characterization procedure and results. Assessment of wavelength jitter on the IPDA measurement error will also be addressed by comparison to the system design.

  1. Systemic Absorption of Nanomaterials by Oral Exposure

    Binderup, Mona-Lise; Bredsdorff, Lea; Beltoft, Vibe Meister;

    This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches.......This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches....

  2. Constraining the Variation of the Fine-structure Constant with Observations of Narrow Quasar Absorption Lines

    Songaila, A.; Cowie, L. L.

    2014-10-01

    The unequivocal demonstration of temporal or spatial variability in a fundamental constant of nature would be of enormous significance. Recent attempts to measure the variability of the fine-structure constant α over cosmological time, using high-resolution spectra of high-redshift quasars observed with 10 m class telescopes, have produced conflicting results. We use the many multiplet (MM) method with Mg II and Fe II lines on very high signal-to-noise, high-resolution (R = 72, 000) Keck HIRES spectra of eight narrow quasar absorption systems. We consider both systematic uncertainties in spectrograph wavelength calibration and also velocity offsets introduced by complex velocity structure in even apparently simple and weak narrow lines and analyze their effect on claimed variations in α. We find no significant change in α, Δα/α = (0.43 ± 0.34) × 10-5, in the redshift range z = 0.7-1.5, where this includes both statistical and systematic errors. We also show that the scatter in measurements of Δα/α arising from absorption line structure can be considerably larger than assigned statistical errors even for apparently simple and narrow absorption systems. We find a null result of Δα/α = (- 0.59 ± 0.55) × 10-5 in a system at z = 1.7382 using lines of Cr II, Zn II, and Mn II, whereas using Cr II and Zn II lines in a system at z = 1.6614 we find a systematic velocity trend that, if interpreted as a shift in α, would correspond to Δα/α = (1.88 ± 0.47) × 10-5, where both results include both statistical and systematic errors. This latter result is almost certainly caused by varying ionic abundances in subcomponents of the line: using Mn II, Ni II, and Cr II in the analysis changes the result to Δα/α = (- 0.47 ± 0.53) × 10-5. Combining the Mg II and Fe II results with estimates based on Mn II, Ni II, and Cr II gives Δα/α = (- 0.01 ± 0.26) × 10-5. We conclude that spectroscopic measurements of quasar absorption lines are not yet capable of

  3. Constraining the variation of the fine-structure constant with observations of narrow quasar absorption lines

    Songaila, A.; Cowie, L. L., E-mail: acowie@ifa.hawaii.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2014-10-01

    The unequivocal demonstration of temporal or spatial variability in a fundamental constant of nature would be of enormous significance. Recent attempts to measure the variability of the fine-structure constant α over cosmological time, using high-resolution spectra of high-redshift quasars observed with 10 m class telescopes, have produced conflicting results. We use the many multiplet (MM) method with Mg II and Fe II lines on very high signal-to-noise, high-resolution (R = 72, 000) Keck HIRES spectra of eight narrow quasar absorption systems. We consider both systematic uncertainties in spectrograph wavelength calibration and also velocity offsets introduced by complex velocity structure in even apparently simple and weak narrow lines and analyze their effect on claimed variations in α. We find no significant change in α, Δα/α = (0.43 ± 0.34) × 10{sup –5}, in the redshift range z = 0.7-1.5, where this includes both statistical and systematic errors. We also show that the scatter in measurements of Δα/α arising from absorption line structure can be considerably larger than assigned statistical errors even for apparently simple and narrow absorption systems. We find a null result of Δα/α = (– 0.59 ± 0.55) × 10{sup –5} in a system at z = 1.7382 using lines of Cr II, Zn II, and Mn II, whereas using Cr II and Zn II lines in a system at z = 1.6614 we find a systematic velocity trend that, if interpreted as a shift in α, would correspond to Δα/α = (1.88 ± 0.47) × 10{sup –5}, where both results include both statistical and systematic errors. This latter result is almost certainly caused by varying ionic abundances in subcomponents of the line: using Mn II, Ni II, and Cr II in the analysis changes the result to Δα/α = (– 0.47 ± 0.53) × 10{sup –5}. Combining the Mg II and Fe II results with estimates based on Mn II, Ni II, and Cr II gives Δα/α = (– 0.01 ± 0.26) × 10{sup –5}. We conclude that spectroscopic measurements of

  4. Constraining the variation of the fine-structure constant with observations of narrow quasar absorption lines

    The unequivocal demonstration of temporal or spatial variability in a fundamental constant of nature would be of enormous significance. Recent attempts to measure the variability of the fine-structure constant α over cosmological time, using high-resolution spectra of high-redshift quasars observed with 10 m class telescopes, have produced conflicting results. We use the many multiplet (MM) method with Mg II and Fe II lines on very high signal-to-noise, high-resolution (R = 72, 000) Keck HIRES spectra of eight narrow quasar absorption systems. We consider both systematic uncertainties in spectrograph wavelength calibration and also velocity offsets introduced by complex velocity structure in even apparently simple and weak narrow lines and analyze their effect on claimed variations in α. We find no significant change in α, Δα/α = (0.43 ± 0.34) × 10–5, in the redshift range z = 0.7-1.5, where this includes both statistical and systematic errors. We also show that the scatter in measurements of Δα/α arising from absorption line structure can be considerably larger than assigned statistical errors even for apparently simple and narrow absorption systems. We find a null result of Δα/α = (– 0.59 ± 0.55) × 10–5 in a system at z = 1.7382 using lines of Cr II, Zn II, and Mn II, whereas using Cr II and Zn II lines in a system at z = 1.6614 we find a systematic velocity trend that, if interpreted as a shift in α, would correspond to Δα/α = (1.88 ± 0.47) × 10–5, where both results include both statistical and systematic errors. This latter result is almost certainly caused by varying ionic abundances in subcomponents of the line: using Mn II, Ni II, and Cr II in the analysis changes the result to Δα/α = (– 0.47 ± 0.53) × 10–5. Combining the Mg II and Fe II results with estimates based on Mn II, Ni II, and Cr II gives Δα/α = (– 0.01 ± 0.26) × 10–5. We conclude that spectroscopic measurements of quasar absorption lines are not yet

  5. The intensity calculation of the gas absorption line by multi-line Voigt fitting

    ZHOU Meng-ran; LI Zhen-bi; ZHONG Ming-yu; HE Gang

    2008-01-01

    Adopted the distribution feedback type (DFB) laser to measure the coal minegas methane,according to the methane located 1.6 pm nearby 2 v3 with a R9 direct ab-sorption spectrum,attraction wire intensity of each line was calculated through the multi-line Voigt fitting.The experimental result indicates that in the obtained four attraction recover of wire,the maximum deviation is 2.7%,and the minimum deviation is 0.02%,other results are all in experimental error scope.This research method may apply in the spectrum survey methane gas density,it has characteristics including high precision,strong selectivity,fast response and so on.

  6. Properties of QSO Metal Line Absorption Systems at High Redshifts: Nature and Evolution of the Absorbers and New Evidence on Escape of Ionizing Radiation from Galaxies

    Boksenberg, Alec

    2014-01-01

    Using Voigt-profile-fitting procedures on Keck HIRES spectra of nine QSOs we identify 1099 CIV absorber components clumped in 201 systems outside the Lyman forest over 1.6 < z < 4.4. With associated SiIV, CII, SiII and NV where available we investigate bulk statistical and ionization properties of the components and systems and find no significant change in redshift for CIV and SiIV while CII, SiII and NV change substantially. The CIV components exhibit strong clustering but no clustering is detected for systems on scales from 150 km/s out to 50000 km/s. We conclude the clustering is due entirely to the peculiar velocities of gas present in the circumgalactic media of galaxies. Using specific combinations of ionic ratios we compare our observations with model ionization predictions for absorbers exposed to the metagalactic ionizing radiation background augmented by proximity radiation from their associated galaxies and find the generally accepted means of radiative escape by transparent channels from th...

  7. Probing variations in fundamental constants with radio and optical quasar absorption-line observations

    Tzanavaris, P; Webb, J K; Flambaum, V V; Curran, S J

    2006-01-01

    Nine quasar absorption spectra at 21-cm and UV rest-wavelengths are used to estimate possible variations in x=alpha^2 g_p mu, (alpha is the fine structure constant, g_p the proton g-factor and mu=me/mp the electron-to-proton mass ratio). We find ^weighted_total(=Dxxwt)=(0.63+-0.99) 10^-5 over 0.23~line-of-sight velocity differences between the 21-cm and UV absorption redshifts, (on average Delta_vlos~6km/s), with random sign and magnitude in each absorption system, limit our precision. Combining our Delta x/x measurement with absorption-line constraints on alpha-variation yields strong limits on the variation of mu. Our most conservative estimate, obtained by assuming no variations in alpha or g_p is Delta mu/mu(=Dmm)=Dxxwt. If we use only the four high-redshift absorbers in our sample, we obtain Dmm=(0.58+-...

  8. Time-Variable Complex Metal Absorption Lines in the Quasar HS1603+3820

    Misawa, T; Charlton, J C; Tajitsu, A; Misawa, Toru; Eracleous, Michael; Charlton, Jane C.; Tajitsu, Akito

    2005-01-01

    We present a new spectrum of the quasar HS1603+3820 taken 1.28 years (0.36 years in the quasar rest frame) after a previous observation with Subaru+HDS. The new spectrum enables us to search for time variability as an identifier of intrinsic narrow absorption lines (NALs). This quasar shows a rich complex of C IV NALs within 60,000 km/s of the emission redshift. Based on covering factor analysis, Misawa et al. found that the C IV NAL system at z_abs= 2.42--2.45 (System A, at a shift velocity of v_sh = 8,300--10,600 km/s relative to the quasar) was intrinsic to the quasar. With our new spectrum, we perform time variability analysis as well as covering factor analysis to separate intrinsic NALs from intervening NALs for 8 C IV systems. Only System A, which was identified as an intrinsic system in the earlier paper by Misawa et al., shows a strong variation in line strength (W_obs ~ 10.4A -> 19.1A). We speculate that a broad absorption line (BAL) could be forming in this quasar. We illustrate the plausibility of...

  9. Line-absorption of He-like triplet lines by Li-like ions: Caveats of using line ratios of triplets for plasma diagnostics

    Mehdipour, M; Raassen, A J J

    2015-01-01

    He-like ions produce distinctive series of triplet lines under various astrophysical conditions. However, this emission can be affected by line-absorption from Li-like ions in the same medium. We investigate this absorption of He-like triplets and present the implications for diagnostics of plasmas in photoionisation equilibrium using the line ratios of the triplets. Our computations are carried out for the O VI and Fe XXIV absorption of the O VII and Fe XXV triplet emission lines, respectively. The fluorescent emission by the Li-like ions and continuum absorption of the He-like ion triplet lines are also investigated. We determine the absorption of the triplet lines as a function of Li-like ion column density and velocity dispersion of the emitting/absorbing medium. We find O VI line-absorption can significantly alter the O VII triplet line ratios in optically-thin plasmas, by primarily absorbing the intercombination lines and to lesser extent the forbidden line. Due to intrinsic line-absorption by O VI insi...

  10. The Properties of Intergalactic CIV Absorption II: Which Systems Are Associated With Galaxy Outflows?

    Songaila, Antoinette

    2005-01-01

    Using the extremely high S/N quasar absorption-line sample described in the first paper of the series, we investigate which intergalactic CIV absorption line systems could be directly associated with galactic outflows at z = 2 - 3.5 from an analysis of the velocity widths of the CIV absorption line systems. Only about half the systems with a peak tau(CIV) above 0.4 in the 1548 Angstrom line (roughly a column density of CIV above about 2 x 10^13 cm^-2) have velocity widths large enough to orig...

  11. Probing the Extended Gaseous Regions of M31 with Quasar Absorption Lines

    Rao, Sandhya; Turnshek, David; Thilker, David; Walterbos, Rene; Berk, Daniel Vanden; York, Donald

    2013-01-01

    We present HST-COS spectra of ten quasars located behind M31, selected to investigate the properties of gas associated with its extended disk and high velocity clouds (HVCs). The sightlines have impact parameters ranging between b= 13 kpc and 112 kpc. No absorption is detected in the four sightlines beyond b=57 kpc. Of the six remaining sightlines, all of which lie at b<32 kpc and within the N(HI)= 2E18 cm^{-2} boundary of the HI disk of M31, we detect low-ionization absorption at M31 velocities along four of them (three of which include MgII absorption). We also detect MgII absorption from an HVC. We find that along sightlines where both are detected, the velocity location of the low-ion gas tracks the peak in 21 cm emission. High-ionization absorption is detected along the three inner sightlines, but not along the three outer sightlines, for which CIV data exist. As inferred from 21 cm emission line maps, only one sightline may have a damped Ly-alpha system. This sightline has b= 17.5 kpc, and we detect ...

  12. Testing Disk-Wind Models with Quasar CIV 1549Å Associated Absorption Lines

    Vestergaard, Marianne

    2012-01-01

    Narrow associated C IV 1549Å absorption lines (NALs) with a rest equivalent width EW =3 Å detected in z ˜ 2 radio-loud and radio-quiet quasars, (a) exhibit evidence of an origin in radiatively accelerated gas, and (b) may be closely related to broad absorption line (BAL) outflows. These NALs and...

  13. Molecular hydrogen absorption systems in SDSS

    Balashev, S A; Ivanchik, A V; Varshalovich, D A; Petitjean, P; Noterdaeme, P

    2014-01-01

    We present a systematic search for molecular hydrogen absorption systems at high redshift in quasar spectra from the Sloan Digital Sky Survey (SDSS) II Data Release 7 and SDSS-III Data Release 9. We have selected candidates using a modified profile fitting technique taking into account that the Ly$\\alpha$ forest can effectively mimic H$_2$ absorption systems at the resolution of SDSS data. To estimate the confidence level of the detections, we use two methods: a Monte-Carlo sampling and an analysis of control samples. The analysis of control samples allows us to define regions of the spectral quality parameter space where H$_2$ absorption systems can be confidently identified. We find that H$_2$ absorption systems with column densities $\\log {\\rm N_{H_2}} > 19$ can be detected in only less than 3% of SDSS quasar spectra. We estimate the upper limit on the detection rate of saturated H$_2$ absorption systems ($\\log {\\rm N_{H_2}} > 19$) in Damped Ly-$\\alpha$ (DLA) systems to be about 7%. We provide a sample of ...

  14. Absorption lines and ion abundances in the QSO PKS 0528-250

    Spectra of the QSO PKS 0528-250 (zsub(e) = 2.765) have been obtained with the AAT at 2 A resolution from 3100 to 7180 A. Absorption line systems have been identified at zsub(A1) = 2.81322, zsub(A2) = 2.81100, zsub(B) = 2.53758 and zsub(C) = 2.14077. The ionization ranges from H I, Al II and Fe II to N V or O VI in system A, from H I and possibly Si II to C IV in B and from H I, Al II and Si II to C IV in C. In system A the Si IV and higher stages are concentrated in A2. Broad Lα profiles in A and C correspond to 2 x 1021 and 5 x 1020 atom cm-2 respectively. Column densities also have been estimated for several heavier elements at each redshift. In system A depletions by factors of 8 to 160 relative to solar abundances appear to be present in S II, O I and N I as well as the typical factor 10 for Si II and Fe II similar to interstellar clouds in the plane of our galaxy. Longward of the Lα absorption in system A there are 44 lines of which only 27 have proposed identifications, whereas at the shorter wavelengths there are 112 lines of which 43 have plausible identifications due to one or more ions other than hydrogen. Thus caution is needed with the common assumption that most absorptions shortward of Lα emission in QSOs are due to Lα. (author)

  15. A new analysis of fine-structure constant measurements and modelling errors from quasar absorption lines

    Wilczynska, Michael R; King, Julian A; Murphy, Michael T; Bainbridge, Matthew B; Flambaum, Victor V

    2015-01-01

    We present an analysis of 23 absorption systems along the lines of sight towards 18 quasars in the redshift range of $0.4 \\leq z_{abs} \\leq 2.3$ observed on the Very Large Telescope (VLT) using the Ultraviolet and Visual Echelle Spectrograph (UVES). Considering both statistical and systematic error contributions we find a robust estimate of the weighted mean deviation of the fine-structure constant from its current, laboratory value of $\\Delta\\alpha/\\alpha=\\left(0.22\\pm0.23\\right)\\times10^{-5}$, consistent with the dipole variation reported in Webb et al. and King et al. This paper also examines modelling methodologies and systematic effects. In particular we focus on the consequences of fitting quasar absorption systems with too few absorbing components and of selectively fitting only the stronger components in an absorption complex. We show that using insufficient continuum regions around an absorption complex causes a significant increase in the scatter of a sample of $\\Delta\\alpha/\\alpha$ measurements, th...

  16. Measuring Changes in the Fundamental Constants with Redshifted Radio Absorption Lines

    Curran, S J; Darling, J K

    2004-01-01

    Strong evidence has recently emerged for a variation in the fine structure constant, $\\alpha\\equiv e^2/\\hbar c$, over the history of the Universe. This was concluded from a detailed study of the relative positions of redshifted optical quasar absorption spectra. However, {\\it radio} absorption lines at high redshift offer a much higher sensitivity to a cosmological change in $\\alpha$ than optical lines. Furthermore, through the comparison of various radio transitions, \\HI, OH and millimetre molecular (e.g. CO) lines, any variations in the proton g-factor, $g_p$, and the ratio of electron/proton masses, $\\mu\\equiv m_e/m_p$, may also be constrained. Presently, however, systems exhibiting redshifted radio lines are rare with the bias being towards those associated with optically selected QSOs. With its unprecedented sensitivity, large bandwidth and wide field of view, the SKA will prove paramount in surveying the sky for absorbers unbiased by dust extinction. This is expected to yield whole new samples of \\HI ~a...

  17. Quasar Absorption Lines in the Far Ultraviolet: An Untapped Gold Mine for Galaxy Evolution Studies

    Tripp, Todd

    2013-01-01

    This white paper emphasizes the potential of QSO absorption lines in the rest-frame far/extreme UV at rest-frame wavelengths from ~500 to 2000 A. In this wavelength range, species such as Ne VIII, Na IX, and Mg X can be detected, providing diagnostics of gas with temperatures >> 10^{6} K, as well as banks of adjacent ions such as O I, O II, O III, O IV, O V, and O VI (and similarly N I - N V; S II - S VI; Ne II - Ne VIII, etc.), which constrain physical conditions with unprecedented precision. A UV spectrograph with good sensitivity down to observed wavelengths of 1000 A can detect these new probes in absorption systems with redshift z(abs) > 0.3, and at these redshifts, the detailed relationships between the absorbers and nearby galaxies and large-scale environment can be studied from the ground. By observing QSOs at z = 1.0 - 1.5, HST has started to exploit extreme-UV QSO absorption lines, but HST can only reach a small number of these targets. A future, more sensitive UV spectrograph could open up this new...

  18. Is there a connection between Broad Absorption Line Quasars and Narrow Line Seyfert 1 galaxies?

    Grupe, Dirk

    2014-01-01

    We consider whether Broad Absorption Line Quasars (BAL QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt & Gallagher (2000) and Boroson (2002). For this purpose we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/Ledd, although BAL QSOs have slightly lower L/Ledd. BAL QSOs and NLS1s in general have high FeII/H$\\beta$ and low [OIII]/H$\\beta$ ratios following the classic 'Boroson \\& Green' eigenvector 1 relation. We also found that the mass accretion rates $\\dot{M}$ of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 \\msun/year. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M-$\\sigma$ plot, we find that BAL QSOs contain fu...

  19. Is there a connection between broad absorption line quasars and narrow-line Seyfert 1 galaxies?

    Grupe, Dirk [Space Science Center, Morehead State University, 235 Martindale Dr., Morehead, KY 40351 (United States); Nousek, John A., E-mail: d.grupe@moreheadstate.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

    2015-02-01

    We consider whether broad absorption line quasars (BAL QSOs) and narrow-line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt and Gallagher and Boroson. For this purpose, we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/L{sub Edd}, although BAL QSOs have slightly lower L/L{sub Edd}. BAL QSOs and NLS1s in general have high Fe ii/Hβ and low [O iii]/Hβ ratios following the classic “Boroson and Green” eigenvector 1 relation. We also found that the mass accretion rates M-dot of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 M{sub ⊙} yr{sup −1}. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M−σ plot, we find that BAL QSOs contain fully developed black holes. Applying a principal component analysis to our sample, we find eigenvector 1 to correspond to the Eddington ratio L/L{sub Edd}, and eigenvector 2 to black hole mass.

  20. A new analysis of fine-structure constant measurements and modelling errors from quasar absorption lines

    Wilczynska, Michael R.; Webb, John K.; King, Julian A.; Murphy, Michael T.; Bainbridge, Matthew B.; Flambaum, Victor V.

    2015-01-01

    We present an analysis of 23 absorption systems along the lines of sight towards 18 quasars in the redshift range of $0.4 \\leq z_{abs} \\leq 2.3$ observed on the Very Large Telescope (VLT) using the Ultraviolet and Visual Echelle Spectrograph (UVES). Considering both statistical and systematic error contributions we find a robust estimate of the weighted mean deviation of the fine-structure constant from its current, laboratory value of $\\Delta\\alpha/\\alpha=\\left(0.22\\pm0.23\\right)\\times10^{-5...

  1. Self-absorption of x-ray spectral lines in an expanding laser plasma

    Results are presented of new experimental investigations of asymmetry of spectral line profiles as a result of the self-absorption of x-ray lines of multiply charged ions in an expanding laser plasma. A theoretical interpretation is based on the solution of the one-dimensional radiation transport equation. Narrowing of the resonance line of the Mg XI ion caused by self-absorption in an inhomogeneous plasma was measured experimentally. The behavior of the profiles of trapped and optically thin spectral lines during gasdynamic expansion of a laser plasma was compared. Narrowing of the resonance line of the Mg XI ion by a factor exceeding 2 was observed

  2. Self-absorption of x-ray spectral lines in an expanding laser plasma

    Boiko, V.A.; Vinogradov, A.V.; Ilyukhin, A.A.; Katulin, V.A.; Maiorov, S.A.; Nosach, V.Y.; Peregudov, G.V.; Petrov, A.L.; Pikuz, S.A.; Skobelev, I.Y.; Faenov, A.Y.; Chirkov, V.A.; Shilov, K.A.

    1981-01-01

    Results are presented of new experimental investigations of asymmetry of spectral line profiles as a result of the self-absorption of x-ray lines of multiply charged ions in an expanding laser plasma. A theoretical interpretation is based on the solution of the one-dimensional radiation transport equation. Narrowing of the resonance line of the Mg XI ion caused by self-absorption in an inhomogeneous plasma was measured experimentally. The behavior of the profiles of trapped and optically thin spectral lines during gasdynamic expansion of a laser plasma was compared. Narrowing of the resonance line of the Mg XI ion by a factor exceeding 2 was observed.

  3. Fraunhofer-type absorption line splitting and polarization in confocal double-pulse laser induced plasma

    Strong line splitting and polarization are observed in Fraunhofer-type absorption lines in Pb, Sn, Si, Cd, In, and Zn in confocal double-pulse laser induced plasma (DP-LIP) experiments. This effect is detectable using medium laser power densities: (∼ 1–2) × 1013 W/m2 for the first laser pulse and 1 × 1014 W/m2 for the second laser pulse. Polarization and splitting effects exist only during the second laser pulse (∼ 7 ns). Absorption line polarization and splitting phenomena may be explained by a high overall magnetic field and motional Stark effect caused by the second laser pulse inside the laser plasma created by the first pulse. - Highlights: • Certain Fraunhofer absorption lines in DP LIBS are polarized. • Certain Fraunhofer absorption lines in DP LIBS are split. • Those effects exist during laser pulse. • Effects take place in elements with ns2np2 and ns2 electron ground state

  4. Non-Voigt Lyman-alpha absorption line profiles

    Outram, P. J.; Carswell, R.F.; Theuns, T.

    1999-01-01

    Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium, and the loss of a physical justification for Voigt profile fitting of the Lyman-alpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We devel...

  5. High-resolution spectroscopy of V854 Cen in decline - absorption and emission lines of C2 molecules

    Kameswara Rao, N.; Lambert, David L.

    2000-04-01

    High-resolution optical spectra of the R Coronae Borealis (RCB) star V854 Centauri in the early stages of a decline show, in addition to the features reported for other RCBs in decline, narrow absorption lines from the C2 Phillips system. The low rotational temperature, Trot=1150K, of the C2 ground electronic state suggests the cold gas is associated with the developing shroud of carbon dust. These absorption lines were not seen at a fainter magnitude on the rise from minimum light, nor at maximum light. This is the first detection of cold gas around an RCB star.

  6. Depths of formation of magnetically sensitive absorption lines

    Sheminova, V A

    2012-01-01

    Characteristics of the depression contribution functions are studied for the Stokes line profiles formed in a magnetic field. The form of the depression functions depends mainly on the strength of splitting and the Zeeman component intensity, and is of a complicated character with a distinctly pronounces asymmetry. The depths of formation of magnetically sensitive lines are found by means of these contribution functions. The calculations reveal that the steep section of the line profile is formed higher than the profile center when a strong longitudinal magnetic field is present. The Stokes profiles that describe the polarization characteristics are formed only several kilometers higher than the Stokes profile that specifies the general depression of the unpolarized and polarized radiation. The averaged depth of formation of the whole line profile is practically independent of the magnetic field strength. The depths of formation of 17 photospheric lines usually used in magnetospectroscopic observations are ca...

  7. The JHU-SDSS metal absorption line catalog: redshift evolution and properties of Mg II absorbers

    Zhu, Guangtun

    2012-01-01

    We present a generic and fully-automatic method aimed at detecting absorption lines in the spectra of astronomical objects. The algorithm estimates the source continuum flux using a dimensionality reduction technique, nonnegative matrix factorization, and then detects and identifies metal absorption lines. We apply it to a sample of ~100,000 quasar spectra from the Sloan Digital Sky Survey and compile a sample of ~40,000 Mg II & Fe II absorber systems, spanning the redshift range 0.4< z < 2.3. The corresponding catalog is publicly available. We study the statistical properties of these absorber systems and find that the rest equivalent width distribution of strong Mg II absorbers follows an exponential distribution at all redshifts, confirming previous studies. Combining our results with recent near-infrared observations of Mg II absorbers we introduce a new parametrization that fully describes the incidence rate of these systems up to z~5. We find the redshift evolution of strong Mg II absorbers to...

  8. Line-Parameter Measurements and Stringent Tests of Line-Shape Models Based on Cavity-Enhanced Absorption Spectroscopy

    Bielska, Katarzyna; Fleisher, Adam J.; Hodges, Joseph T.; Lin, Hong; Long, David A.; Reed, Zachary D.; Sironneau, Vincent; Truong, Gar-Wing; Wójtewicz, Szymon

    2014-06-01

    Laser methods that are based on cavity-enhanced absorption spectroscopy (CEAS) are well-suited for measuring molecular line parameters under conditions of low optical density, and as such they are complementary to broadband Fourier-transform spectroscopy (FTS) techniques. Attributes of CEAS include relatively low detection limits, accurate and precise detuning axes and high fidelity measurements of line shape. In many cases these performance criteria are superior to those obtained using direct laser absorption spectroscopy and FTS-based systems. In this presentation we will survey several examples of frequency-stabilized cavity ring-down spectroscopy (FS-CRDS)1 measurements obtained with laser spectrometers developed at the National Institute of Standards and Technology (NIST) in Gaithersburg Maryland. These experiments, which are motivated by atmospheric monitoring and remote-sensing applications that require high-precision and accuracy, involve nearinfrared transitions of carbon dioxide, water, oxygen and methane. We discuss spectra with signal-to-noise ratios exceeding 106, frequency axes with absolute uncertainties in the 10 kHz to 100 kHz range and linked to a Cs clock, line parameters with relative uncertainties at the 0.2 % level and isotopic ratios measured with a precision of 0.03 %. We also present FS-CRDS measurements of CO2 line intensities which are measured at atmospheric concentration levels and linked to gravimetric standards for CO2 in air, and we quantify pressure-dependent deviations between various theoretical line profiles and measured line shapes. Finally we also present recent efforts to increase data throughput and spectral coverage in CEAS experiments. We describe three new high-bandwidth CEAS techniques including frequency-agile, rapid scanning spectroscopy (FARS)2, which enables continuous-wave measurements of cavity mode linewidth and acquisition of ringdown decays with no dead time during laser frequency tuning, heterodyne

  9. Observing broad-absorption line quasars with Spectrum-Rontgen-Gamma

    Singh, K.P.; Schnopper, H.W.; Westergaard, Niels Jørgen Stenfeldt

    Broad-absorption line quasars are found to have extremely weak soft X-ray emission when compared with other optically selected quasars. In the only example of PHL 5200 for which a detailed X-ray spectrum has been obtained with ASCA, strong absorption in the source appears to be responsible for the...

  10. Measuring changes in the fundamental constants with redshifted radio absorption lines

    Curran, SJ; Kanekar, N; Darling, JK

    2004-01-01

    Strong evidence has recently emerged for a variation in the fine structure constant, alpha equivalent to e(2)/hc, over the history of the Universe. This was concluded from a detailed study of the relative positions of redshifted optical quasar absorption spectra. However, radio absorption lines at h

  11. Discovery of Extremely Broad Balmer Absorption Lines in SDSS J152350.42+391405.2

    Zhang, Shaohua; Shi, Xiheng; Shu, Xinwen; Liu, Wenjuan; Ji, Tuo; Jiang, Peng; Sun, Luming; Zhou, Junyan; Pan, Xiang

    2015-01-01

    We present the discovery of Balmer line absorption from H$\\alpha$ to H$\\gamma$ in an iron low-ionization broad absorption line (FeLoBAL) quasar SDSS J152350.42+391405.2 (hereafter J1523), by the quasi-simultaneous optical and near-infrared spectroscopy. The Balmer line absorption is at $z_{absor}$ = 0.6039 +/-0.0021 and blueshifted by v=10,353 km/s with respect to the Balmer emission lines. All Balmer BALs have uniform absorption profile with the widths of $\\Delta$ v ~12,000 km/s. We also found the absorption trough in He 1* $\\lambda$10830 with the same velocity and width in the H-band TripleSpec spectrum of J1523. This object is only the tenth active galactic nucleus known to exhibit non-stellar Balmer absorption, and also the case with the highest velocity and broadest Balmer absorption lines which have ever been found. A CLOUDY analysis shows that the absorbers require an gas density of $log_{10} n_ e (cm^{-3})=9$ and an ionization parameter of $log_{10} U=-1.0$. They locate at a distance of ~0.2 pc from t...

  12. CRIRES spectroscopy and empirical line-by-line identification of FeH molecular absorption in an M dwarf

    Wende, S.; Reiners, A.; Seifahrt, A.; Bernath, P. F.

    2010-11-01

    Molecular FeH provides a large number of sharp and isolated absorption lines that can be used to measure radial velocity, rotation, or magnetic field strength with high accuracy. Our aim is to provide an FeH atlas for M-type stars in the spectral region from 986 nm to 1077 nm (Wing-Ford band). To identify these lines in CRIRES spectra of the magnetically inactive, slowly rotating, M5.5 dwarf GJ1002, we calculated model spectra for the selected spectral region with theoretical FeH line data. In general this line list agrees with the observed data, but several individual lines differ significantly in position or in line strength. After identification of as many as possible FeH lines, we corrected the line data for position and line strength to provide an accurate atlas of FeH absorption lines for use in high precision spectroscopy of low mass stars. For all lines, we used a Voigt function to obtain their positions and equivalent widths. Identification with theoretical lines was done by hand. For confirmation of the identified lines, we used statistical methods, cross-correlation techniques, and line intensities. Eventually, we were able to identify FeH lines from the (0,0), (1,0), (1,1), (2,1), (2,2), (3,2), and (4,3) vibrational bands in the observed spectra and correct the positions of the lines if necessary. The deviations between theoretical and observed positions follow a normal distribution approximately around zero. In order to empirically correct the line strength, we determined Teff, instrumental broadening (rotational broadening) and a van der Waals enhancement factor for the FeH lines in GJ1002. We also give the scaling factors for the Einstein A values to correct the line strengths. With the identified lines, we derived rotational temperatures from the line intensities for GJ1002. We conclude that FeH lines can be used for a wide variety of applications in astrophysics. With the identified lines it will be possible for example to characterize magnetically

  13. Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line

    Richter, Heiko; Pavlov, Sergei G.; Semenov, A. D.; Mahler, L.; Tredicucci, A.; Beere, H.E.; Ritchie, D. A.; Hübers, H. -W.

    2010-01-01

    The frequency of a terahertz quantum-cascade laser is stabilized to the absorption line of methanol gas at a frequency of 2.55 THz. The method is based on frequency modulation of the laser emissionm across the absorption line. The resulting derivativelike signal is used as an error signal for a control loop that keeps the laser frequency at maximum absorption. The unstabilized laser that is operated in a pulse tube cooler has frequency fluctuations of 15 MHz, which are reduced to 300 kHz with...

  14. The interstellar absorption-line spectrum of Mu Ophiuchi

    Cardelli, J.; Boehm-Vitense, E.

    1982-01-01

    UV interstellar lines have been measured on high-resolution, long- and short-wavelength IUE spectra of the B8 V star Mu Oph. Column densities for the observed atoms and ions have been determined as well as turbulent velocities. The interstellar spectrum of Mu Oph is similar to the ones for Rho Oph and Zeta Oph. The ionization equilibria of several elements give consistent limits for the electron density. The C I line arising from different fine-structure levels are studied to yield estimates on the physical conditions in the cloud. Relative depletion of elements in the cloud seen in the interstellar spectrum of Mu Oph follows the same pattern as seen in the interstellar spectra of Zeta Oph and six other stars in the Rho Oph cloud complex.

  15. Experimental design and methodology for a new Moessbauer scan experiment: absorption line tracking

    A new experimental setup and methodology that allows the automatic tracking of a Moessbauer absorption line as its energy position varies during the experiment is introduced. As a test the sixth spectral line of FeSn2 was tracked while temperature was varied between room temperature and a value slightly above its Neel temperature.

  16. Study of cancer cell lines with Fourier transform infrared (FTIR)/vibrational absorption (VA) spectroscopy

    Uceda Otero, E. P.; Eliel, G. S. N.; Fonseca, E. J. S.;

    2013-01-01

    In this work we have used Fourier transform infrared (FTIR) / vibrational absorption (VA) spectroscopy to study two cancer cell lines: the Henrietta Lacks (HeLa) human cervix carcinoma and 5637 human bladder carcinoma cell lines. Our goal is to experimentally investigate biochemical changes and d...

  17. Variation in Emission and Absorption Lines and Continuum Flux by Orbital Phase in Vela X-1

    Goldstein, G R; Blank, D

    2004-01-01

    High resolution spectral studies were undertaken at orbital phases 0, 0.25 and 0.5 on the high-mass X-ray binary (HMXB) Vela X-1 using archival Chandra data. We present (a) the first detailed analysis of the multiple strong narrow emission lines present in phase 0.5 (b) an analysis of the absorption of the continuum in phase 0.5, and (c) the first detection of narrow emission and absorption lines in phase 0.25. Multiple fluorescent and H-and He-like emission lines in the band 1.6 - 20 Angstrom in eclipse are partially obscured at phase 0.25 by the X-ray continuum. The phase 0.25 spectrum displays 3 triplets, 2 with a blue-shifted resonance (r) line in absorption and the intercombination (i) and forbidden (f) lines in emission, and shows in absorption other blue-shifted lines seen in emission in eclipse. At phase 0.5 the soft X-ray continuum diminishes revealing an "eclipse-like" spectrum, however line flux values are around 13-fold those in eclipse. We conclude the narrow emission lines in Vela X-1 become app...

  18. ON THE DIVERSITY AND COMPLEXITY OF ABSORPTION LINE PROFILES PRODUCED BY OUTFLOWS IN ACTIVE GALACTIC NUCLEI

    Understanding the origin of active galactic nucleus (AGN) absorption line profiles and their diversity could help to explain the physical structure of the accretion flow, and also to assess the impact of accretion on the evolution of the AGN host galaxies. Here, we present our first attempt to systematically address the issue of the origin of the complexities observed in absorption profiles. Using a simple method, we compute absorption line profiles against a continuum point source for several simulations of accretion disk winds. We investigate the geometrical, ionization, and dynamical effects on the absorption line shapes. We find that significant complexity and diversity of the absorption line profile shapes can be produced by the non-monotonic distribution of the wind velocity, density, and ionization state. Non-monotonic distributions of such quantities are present even in steady-state, smooth disk winds, and naturally lead to the formation of multiple and detached absorption troughs. These results demonstrate that the part of a wind where an absorption line is formed is not representative of the entire wind. Thus, the information contained in the absorption line is incomplete if not even insufficient to well estimate gross properties of the wind such as the total mass and energy fluxes. In addition, the highly dynamical nature of certain portions of disk winds can have important effects on the estimates of the wind properties. For example, the mass outflow rates can be off by up to two orders of magnitude with respect to estimates based on a spherically symmetric, homogeneous, constant velocity wind.

  19. Discovery of Carbon Radio Recombination Lines in absorption towards Cygnus~A

    Oonk, J B R; Salgado, F; Morabito, L K; Tielens, A G G M; Rottgering, H J A; Asgekar, A; White, G J; Alexov, A; Anderson, J; Avruch, I M; Batejat, F; Beck, R; Bell, M E; van Bemmel, I; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Brentjens, M; Broderick, J; Brueggen, M; Butcher, H R; Ciardi, B; Conway, J E; Corstanje, A; de Gasperin, F; de Geus, E; de Vos, M; Duscha, S; Eisloeffel, J; Engels, D; van Enst, J; Falcke, H; Fallows, R A; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; Griessmeier, J; Hamaker, J P; Hassall, T E; Heald, G; Hessels, J W T; Hoeft, M; Horneffer, A; van der Horst, A; Iacobelli, M; Jackson, N J; Juette, E; Karastergiou, A; Klijn, W; Kohler, J; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Maat, P; Macario, G; Mann, G; Markoff, S; McKean, J P; Mevius, M; Miller-Jones, J C A; Mol, J D; Mulcahy, D D; Munk, H; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pandey, V N; Pizzo, R; Polatidis, A G; Reich, W; Scaife, A M M; Schoenmakers, A; Schwarz, D; Shulevski, A; Sluman, J; Smirnov, O; Sobey, C; Stappers, B W; Steinmetz, M; Swinbank, J; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Thoudam, S; Toribio, C; van Nieuwpoort, R; Vermeulen, R; Vocks, C; Vogt, C; Wijers, R A M J; Wise, M W; Wucknitz, O; Yatawatta, S; Zarka, P; Zensus, A

    2014-01-01

    We present the first detection of carbon radio recombination line absorption along the line of sight to Cygnus A. The observations were carried out with the LOw Frequency ARray in the 33 to 57 MHz range. These low frequency radio observations provide us with a new line of sight to study the diffuse, neutral gas in our Galaxy. To our knowledge this is the first time that foreground Milky Way recombination line absorption has been observed against a bright extragalactic background source. By stacking 48 carbon $\\alpha$ lines in the observed frequency range we detect carbon absorption with a signal-to-noise ratio of about 5. The average carbon absorption has a peak optical depth of 2$\\times$10$^{-4}$, a line width of 10 km s$^{-1}$ and a velocity of +4 km s$^{-1}$ with respect to the local standard of rest. The associated gas is found to have an electron temperature $T_{e}\\sim$ 110 K and density $n_{e}\\sim$ 0.06 cm$^{-3}$. These properties imply that the observed carbon $\\alpha$ absorption likely arises in the c...

  20. The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations

    Miller, Matthew J.; Hodges-Kluck, Edmund J.; Bregman, Joel N.

    2016-02-01

    Detections of z ≈ 0 oxygen absorption and emission lines indicate the Milky Way hosts a hot (˜ {10}6 K), low-density plasma extending ≳ 50 {{kpc}} into the Mily Way’s halo. Current X-ray telescopes cannot resolve the line profiles, but the variation of their strengths on the sky constrains the radial gas distribution. Interpreting the O vii Kα absorption line strengths has several complications, including optical depth and line of sight velocity effects. Here, we present model absorption line profiles accounting for both of these effects to show the lines can exhibit asymmetric structures and be broader than the intrinsic Doppler width. The line profiles encode the hot gas rotation curve, the net inflow or outflow of hot gas, and the hot gas angular momentum profile. We show how line of sight velocity effects impact the conversion between equivalent width and the column density, and provide modified curves of growth accounting for these effects. As an example, we analyze the LMC sight line pulsar dispersion measure and O vii equivalent width to show the average gas metallicity is ≳ 0.6{Z}⊙ and b ≳ 100 km s-1. Determining these properties offers valuable insights into the dynamical state of the Milky Way’s hot gas, and improves the line strength interpretation. We discuss future strategies to observe these effects with an instrument that has a spectral resolution of about 3000, a goal that is technically possible today.

  1. Broad absorption line quasars have the same cool dust emission as quasars without BALs

    Willott, Chris J.; Rawlings, Steve; Grimes, Jennifer A.

    2003-01-01

    The results of a sub-millimeter survey of SDSS broad CIV absorption line quasars is discussed. It is found that the sub-millimeter flux distribution of BAL quasars is similar to that of non-BAL quasars. This is consistent with the idea that all quasars contain broad absorption line regions, but only a fraction of them are visible along our line-of-sight. The observations are inconsistent with BAL quasars being observed at a special evolutionary epoch co-inciding with a high star-formation rat...

  2. Made-to-measure galaxy modelling utilising absorption line strength data

    Long, Richard

    2016-01-01

    We enhance the Syer & Tremaine made-to-measure (M2M) particle method of stellar dynamical modelling to model simultaneously both kinematic data and absorption line strength data thus creating a `chemo-M2M' modelling scheme. We apply the enhanced method to four galaxies (NGC 1248, NGC 3838, NGC 4452, NGC 4551) observed using the SAURON integral-field spectrograph as part of the ATLAS3D programme. We are able to reproduce successfully the 2D line strength data achieving mean chi^2 per bin values of ~1 with >95\\% of particles having converged weights. Because M2M uses a 3D particle system, we are also able to examine the underlying 3D line strength distributions. The extent to which these distributions are plausible representations of real galaxies requires further consideration. Overall we consider the modelling exercise to be a promising first step in developing a `chemo-M2M' modelling system and in understanding some of the issues to be addressed. Whilst the made-to-measure techniques developed have been ...

  3. Epoch-dependent absorption line profile variability in lambda Cep

    Uuh-Sonda, J M; Eenens, P; Mahy, L; Palate, M; Gosset, E; Flores, C A

    2014-01-01

    We present the analysis of a multi-epoch spectroscopic monitoring campaign of the O6Ief star lambda Cep. Previous observations reported the existence of two modes of non-radial pulsations in this star. Our data reveal a much more complex situation. The frequency content of the power spectrum considerably changes from one epoch to the other. We find no stable frequency that can unambiguously be attributed to pulsations. The epoch-dependence of the frequencies and variability patterns are similar to what is seen in the wind emission lines of this and other Oef stars, suggesting that both phenomena likely have the same, currently still unknown, origin.

  4. Interstellar absorption lines in the directions of extragalactic objects

    Observations of Na I and Ca II interstellar lines with resolutions as fine as 24 and 17 km s-1 respectively have been obtained in the directions of the extragalactic sources NGC 985, 1068, 3C273, 1916-588 and Mkn 509. They all show a component with |Vsub(LSR)| -1 which is attributed primarily to gas in the galactic disc with |z| -1 and in Mkn 509 at +61 km s-1 and an extended negative velocity wing already has been noted in SN 1980n in NGC 1316. The ratio of Ca II to Na I column densities is high compared with typical stars shining through H I clouds in the galactic plane, indicating that both the low- and high-velocity clouds in the survey are more typical of intercloud gas where calcium is much less depleted. (author)

  5. Discovery of carbon radio recombination lines in absorption towards Cygnus A

    Oonk, J. B. R.; van Weeren, R. J.; Salgado, F.; Morabito, L. K.; Tielens, A. G. G. M.; Rottgering, H. J. A.; Asgekar, A.; White, G. J.; Alexov, A.; Anderson, J.; Avruch, I. M.; Batejat, F.; Beck, R.; Bell, M. E.; van Bemmel, I.; Bentum, M. J.; Bernardi, G.; Best, P.; Bonafede, A.; Breitling, F.; Brentjens, M.; Broderick, J.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Conway, J. E.; Corstanje, A.; de Gasperin, F.; de Geus, E.; de Vos, M.; Duscha, S.; Eislöffel, J.; Engels, D.; van Enst, J.; Falcke, H.; Fallows, R. A.; Fender, R.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Hamaker, J. P.; Hassall, T. E.; Heald, G.; Hessels, J. W. T.; Hoeft, M.; Horneffer, A.; van der Horst, A.; Iacobelli, M.; Jackson, N. J.; Juette, E.; Karastergiou, A.; Klijn, W.; Kohler, J.; Kondratiev, V. I.; Kramer, M.; Kuniyoshi, M.; Kuper, G.; van Leeuwen, J.; Maat, P.; Macario, G.; Mann, G.; Markoff, S.; McKean, J. P.; Mevius, M.; Miller-Jones, J. C. A.; Mol, J. D.; Mulcahy, D. D.; Munk, H.; Norden, M. J.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pandey, V. N.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Scaife, A. M. M.; Schoenmakers, A.; Schwarz, D.; Shulevski, A.; Sluman, J.; Smirnov, O.; Sobey, C.; Stappers, B. W.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; Veen, S. ter; Thoudam, S.; Toribio, C.; van Nieuwpoort, R.; Vermeulen, R.; Vocks, C.; Vogt, C.; Wijers, R. A. M. J.; Wise, M. W.; Wucknitz, O.; Yatawatta, S.; Zarka, P.; Zensus, A.

    2014-02-01

    We present the first detection of carbon radio recombination line absorption along the line of sight to Cygnus A. The observations were carried out with the Low Frequency Array in the 33-57 MHz range. These low-frequency radio observations provide us with a new line of sight to study the diffuse, neutral gas in our Galaxy. To our knowledge this is the first time that foreground Milky Way recombination line absorption has been observed against a bright extragalactic background source. By stacking 48 carbon α lines in the observed frequency range we detect carbon absorption with a signal-to-noise ratio of about 5. The average carbon absorption has a peak optical depth of 2 × 10-4, a line width of 10 km s-1 and a velocity of +4 km s-1 with respect to the local standard of rest. The associated gas is found to have an electron temperature Te ˜ 110 K and density ne ˜ 0.06 cm-3. These properties imply that the observed carbon α absorption likely arises in the cold neutral medium of the Orion arm of the Milky Way. Hydrogen and helium lines were not detected to a 3σ peak optical depth limit of 1.5 × 10-4 for a 4 km s-1 channel width. Radio recombination lines associated with Cygnus A itself were also searched for, but are not detected. We set a 3σ upper limit of 1.5 × 10-4 for the peak optical depth of these lines for a 4 km s-1 channel width.

  6. Spectroscopic measurements of a CO2 absorption line in an open vertical path using an airborne lidar

    Ramanathan, Anand; Allan, Graham R; Riris, Haris; Weaver, Clark J; Hasselbrack, William E; Browell, Edward V; Abshire, James B

    2013-01-01

    We use an airborne pulsed integrated path differential absorption lidar to make spectroscopic measurements of the pressure-induced line broadening and line center shift of atmospheric CO2 at the 1572.335 nm absorption line. We measure the absorption lineshape in the vertical column between the aircraft and ground. A comparison of our measured absorption lineshape to calculations based on HITRAN shows excellent agreement with the peak optical depth accurate to within 0.3%. Additionally, we measure changes in the line center position to within 5.2 MHz of calculations, and the absorption linewidth to within 0.6% of calculations.

  7. On-line sipping system

    To identify leaking fuel assemblies during core unloading, PWR utilities use systems such as sipping tests, ultrasonic or eddy current detection. For this purpose, FRAGEMA proposes an on-line sipping test system, the process of which is patented by CEA. This system is installed on the refuelling machine in the reactor building. This on-line system based on gaseous fission products detection detects leaking fuel assembly during fuel handling and thus provides a significant refuelling outage time saving. In addition, the system installation and operation present other interesting features: Mast equipment installed on the machine without modifications to the mast mechanical structure, only two days are necessary for the first installation, and it's a self-operated equipment (no additional operator required for driving the system). (author). 3 figs

  8. Laboratory verification of on-line lithium analysis using ultraviolet absorption spectrometry

    Several laboratory experiments were performed to evaluate the capability of absorption spectrometry in the ultraviolet-visible wavelength range with the objective of developing methods for on-line analysis of lithium directly in the primary coolant of Pressurized Water Reactors using optical probes. Although initial laboratory tests seemed to indicate that lithium could be detected using primary absorption (detection of natural spectra unassisted by reagents), subsequent field tests demonstrated that no primary absorption spectra existed for lithium in the ultraviolet-visible wavelength range. A second series of tests that were recently conducted did, however, confirm results reported in the literature to the effect that reagents were available that will react with lithium to form chelates that possess detectable absorption and fluorescent signatures. These results point to the possible use of secondary techniques for on-line analysis of lithium

  9. Empirical line lists and absorption cross sections for methane at high temperature

    Hargreaves, Robert J; Bailey, Jeremy; Dulick, Michael

    2015-01-01

    Hot methane is found in many "cool" sub-stellar astronomical sources including brown dwarfs and exoplanets, as well as in combustion environments on Earth. We report on the first high-resolution laboratory absorption spectra of hot methane at temperatures up to 1200 K. Our observations are compared to the latest theoretical spectral predictions and recent brown dwarf spectra. The expectation that millions of weak absorption lines combine to form a continuum, not seen at room temperature, is confirmed. Our high-resolution transmittance spectra account for both the emission and absorption of methane at elevated temperatures. From these spectra, we obtain an empirical line list and continuum that is able to account for the absorption of methane in high temperature environments at both high and low resolution. Great advances have recently been made in the theoretical prediction of hot methane, and our experimental measurements highlight the progress made and the problems that still remain.

  10. Interstellar absorption lines in the directions of extragalactic objects. 1

    Blades, J.C. (Rutherford Appleton Lab., Chilton (UK)); Morton, D.C. (Anglo-Australian Observatory, Epping (Australia))

    1983-07-01

    Observations of Na I and Ca II interstellar lines with resolutions as fine as 24 and 17 km s/sup -1/ respectively have been obtained in the directions of the extragalactic sources NGC 985, 1068, 3C273, 1916-588 and Mkn 509. They all show a component with Vertical BarVsub(LSR)Vertical Bar <= 10 km s/sup -1/ which is attributed primarily to gas in the galactic disc with Vertical BarzVertical Bar <= 1 kpc based on comparisons with high-latitude stars. Higher velocity components of both Na I and Ca II were discovered in 3C 273 at- 22 and +28 km s/sup -1/ and in Mkn 509 at +61 km s/sup -1/ and an extended negative velocity wing already has been noted in SN 1980n in NGC 1316. The ratio of Ca II to Na I column densities is high compared with typical stars shining through H I clouds in the galactic plane, indicating that both the low- and high-velocity clouds in the survey are more typical of intercloud gas where calcium is much less depleted.

  11. The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations

    Miller, Matthew J; Bregman, Joel N

    2016-01-01

    Detections of $z \\approx$ 0 oxygen absorption and emission lines indicate the Milky Way hosts a hot ($\\sim 10^6$ K), low-density plasma extending $\\gtrsim$50 kpc into the Mily Way's halo. Current X-ray telescopes cannot resolve the line profiles, but the variation of their strengths on the sky constrains the radial gas distribution. Interpreting the OVII K$\\alpha$ absorption line strengths has several complications, including optical depth and line of sight velocity effects. Here, we present model absorption line profiles accounting for both of these effects to show the lines can exhibit asymmetric structures and be broader than the intrinsic Doppler width. The line profiles encode the hot gas rotation curve, the net inflow or outflow of hot gas, and the hot gas angular momentum profile. We show how line of sight velocity effects impact the conversion between equivalent width and the column density, and provide modified curves of growth accounting for these effects. As an example, we analyze the LMC sight lin...

  12. Subaru high resolution spectroscopy of complex metal absorption lines of QSO HS1603+3820

    Misawa, T; Takada-Hidai, M; Wang, Y; Kashikawa, N; Iye, M; Tanaka, I; Misawa, Toru; Yamada, Toru; Takada-Hidai, Masahide; Wang, Yiping; Kashikawa, Nobunari; Iye, Masanori; Tanaka, Ichi

    2002-01-01

    We present a high resolution spectrum of the quasar, HS1603+3820 (z_em=2.542), observed with the High Dispersion Spectrograph (HDS) on Subaru Telescope. This quasar, first discovered in the Hamburg/CfA Quasar Survey, has 11 C IV lines at 1.96 2.29 and resolves some of them into multiple narrow components with b 65 km/s). We use three properties of C IV lines, specifically, time variability, covering factor, and absorption line profile, to classify them into quasar intrinsic absorption lines (QIALs) and spatially intervening absorption lines (SIALs). The C IV lines at 2.42 < z_abs < 2.45 are classified as QIALs in spite of their large velocity shifts from the quasar. Perhaps they are produced by gas clouds ejected from the quasar with the velocity of v_ej = 8000 km/s -- 10000 km/s. On the other hand, three C IV lines at 2.48 < z_abs < 2.55 are classified as SIALs, which suggests there exist intervening absorbers near the quasar. We, however, cannot rule out QIALs for the two lines at z_abs ~ 2.54...

  13. Reionization and high-redshift galaxies: the view from quasar absorption lines

    Becker, George D; Lidz, Adam

    2015-01-01

    Determining when and how the first galaxies reionized the intergalactic medium (IGM) promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing the properties of diffuse gas on galactic and intergalactic scales. In this review we examine the multiple ways in which absorption lines trace the connection between galaxies and the IGM near the reionization epoch. We first describe how the Ly$\\alpha$ forest is used to determine the intensity of the ionizing ultraviolet background and the global ionizing emissivity budget. Critically, these measurements reflect the escaping ionizing radiation from all galaxies, including those too faint to detect directly. We then discuss insights from metal absorption lines into reionization-era galaxies and their surroundings. Current observations suggest a buildup of metals in the circumgalactic environments of galaxies over $z \\sim 6$ to 5, although changes in ionizati...

  14. Absorption-line survey of 32 QSOs at red wavelengths - properties of the Mg II absorbers

    The results of a survey of 32 QSOs for Mg II absorption at red wavelengths are presented, and the properties of the metal absorption systems are investigated. When interpreted in terms of ejection, the Mg II absorption systems are randomly distributed in velocity relative to the QSOs, although the systems may cluster on scales of a few thousand km/s. This is consistent with the absorption systems arising in intervening material not associated with the QSOs. The equivalent width distribution of the Mg II systems is well fitted by either an exponential or a power-law distribution, with the number density of the absorption systems increasing with decreasing rest equivalent width. There is marginally significant evidence for cosmological evolution of the number density of the Mg II absorbers, and no evidence for evolution of the Mg II equivalent width distribution with redshift. 42 references

  15. Absorption-line survey of 32 QSOs at red wavelengths - properties of the Mg II absorbers

    Lanzetta, K.M.; Wolfe, A.M.; Turnshek, D.A.

    1987-11-01

    The results of a survey of 32 QSOs for Mg II absorption at red wavelengths are presented, and the properties of the metal absorption systems are investigated. When interpreted in terms of ejection, the Mg II absorption systems are randomly distributed in velocity relative to the QSOs, although the systems may cluster on scales of a few thousand km/s. This is consistent with the absorption systems arising in intervening material not associated with the QSOs. The equivalent width distribution of the Mg II systems is well fitted by either an exponential or a power-law distribution, with the number density of the absorption systems increasing with decreasing rest equivalent width. There is marginally significant evidence for cosmological evolution of the number density of the Mg II absorbers, and no evidence for evolution of the Mg II equivalent width distribution with redshift. 42 references.

  16. Modelling of the X-ray broad absorption features in Narrow-Line Seyfert 1s

    Porquet, D; Dumont, A M

    2000-01-01

    We investigate the origin of the broad absorption features detected near 1-1.4 keV in several Narrow Line Seyfert 1 galaxies, by modelling the absorbing medium with various physical parameters, using the ionization code PEGAS. The observed properties of the X-ray absorption features can be reproduced by taking into account the peculiar soft X-ray excess which is well fitted by a blackbody plus an underlying power law. We equally stress that the emission coming from the absorbing medium (related to the covering factor) has a strong influence on the resulting X-ray spectrum, in particular on the apparent position and depth of the absorption features. A non-solar iron abundance may be required to explain the observed deep absorption. We also investigate the influence of an additional collisional ionization process (hybrid case) on the predicted absorption features.

  17. Modelling of the X-ray broad absorption features in Narrow-Line Seyfert 1s

    Porquet, Delphine; Mouchet, Martine; Dumont Anne-Marie

    2000-09-01

    We investigate the origin of the broad absorption features detected near 1-1.4 keV in several Narrow-Line Seyfert 1 galaxies, by modelling the absorbing medium with various physical parameters, using the ionization code PEGAS. The observed properties of the X-ray absorption features can be reproduced by taking into account the peculiar soft X-ray excess which is well fitted by a blackbody plus an underlying power law. We equally stress that the emission coming from the absorbing medium (related to the covering factor) has a strong influence on the resulting X-ray spectrum, in particular on the apparent position and depth of the absorption features. A non-solar iron abundance may be required to explain the observed deep absorption. We also investigate the influence of an additional collisional ionization process ("hybrid case") on the predicted absorption features.

  18. Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in PDS 456

    Reeves, James; Nardini, Emanuele; Behar, Ehud; O'Brien, Paul; Tombesi, Francesco; Turner, Tracey Jane; Costa, Michele

    2016-01-01

    High resolution soft X-ray spectroscopy of the prototype accretion disk wind quasar, PDS 456, is presented. Here, the XMM-Newton RGS spectra are analyzed from the large 2013-2014 XMM-Newton campaign, consisting of 5 observations of approximately 100 ks in length. During the last observation (hereafter OBS. E), the quasar is at a minimum flux level and broad absorption line profiles are revealed in the soft X-ray band, with typical velocity widths of $\\sigma_{\\rm v}\\sim 10,000$ km s$^{-1}$. During a period of higher flux in the 3rd and 4th observations (OBS. C and D, respectively), a very broad absorption trough is also present above 1 keV. From fitting the absorption lines with models of photoionized absorption spectra, the inferred outflow velocities lie in the range $\\sim 0.1-0.2c$. The absorption lines likely originate from He and H-like neon and L-shell iron at these energies. Comparison with earlier archival data of PDS 456 also reveals similar absorption structure near 1 keV in a 40 ks observation in 20...

  19. Analysis of a solar powered absorption system

    Highlights: • Conventional absorption system modified to increase COP. • Results indicated increase of 10% in COP due to dephlegmator heat recovery. • Results indicated increase of 8% in COP due to refrigerant storage unit. • Results indicated increase of 18% in COP due to combined effect of modifications. • Simulation results indicated a very good agreement with the measured results. - Abstract: Today, fossil fuel is the primary extensively used source of energy. However, its negative impact on the environment have forced the energy research continuity to seriously consider renewable sources of energy. Solar energy, in particular, has been the main focus in this regard because it is a source of clean energy and naturally available. This study presents the design and analysis of a solar powered absorption refrigeration system modified to increase its coefficient of performance (COP). The modifications include recovering of waste heat from a dephlegmator and utilization of a refrigerant storage unit. The simulation results indicate an increase of 10% in the COP of the conventional design using dephlegmator heat recovery and an increase of 8% in the COP of the conventional design due to the use of a refrigerant storage. The analysis for the combined effect of modifications indicates an increase of 18% in the COP compared to conventional design. Calculated values of coefficient of performance indicate a very good agreement with the ones obtained based on measurement

  20. Exploratory Study of the X-Ray Properties of Quasars With Intrinsic Narrow Absorption Lines

    Misawa, Toru; Eracleous, Michael; Chartas, George; Charlton, Jane C.

    2008-01-01

    We have used archival Chandra and XMM-Newton observations of quasars hosting intrinsic narrow UV absorption lines (intrinsic NALs) to carry out an exploratory survey of their X-ray properties. Our sample consists of three intrinsic-NAL quasars and one "mini-BAL" quasar, plus four quasars without intrinsic absorption lines for comparison. These were drawn in a systematic manner from an optical/UV-selected sample. The X-ray properties of intrinsic-NAL quasars are indistinguishable from those of...

  1. Absorption spectra of broadened sodium resonance lines in presence of rare gases

    The pressure broadening of alkali-metal lines is a fundamental problem with numerous applications. For example, the sodium resonance lines broadened by xenon are important in the production of broad spectra emitted in the HPS (High-Pressure Sodium) lamp and they potentially can be used for gas condition diagnostics. Broadened absorption lines of alkali-metal atoms are prominent in the optical spectra of brown dwarfs and understanding the broadening mechanism will help elucidate the chemical composition and atmospheric properties of those stars. The far-line wing spectra of sodium resonance lines broadened by rare gases are found to exhibit molecular characteristics such as satellites and hence the total absorption coefficients for vapors of Na atoms and perturbing rare gas atoms can be modeled as Na-RG (rare gas) molecular absorption spectra. In this work, using carefully chosen interatomic potentials for Na-RG molecules we carry out quantum-mechanical calculations for reduced absorption coefficients for vapors composed of Na-He, Na-Ar, and Na-Xe. Calculated spectra are compared to available experimental results and the agreement is good in the measured satellite positions and shapes

  2. On the Origin of the Wide HI Absorption Line towards Sgr A*

    K. S. Dwarakanath; W. M. Goss; J. H. Zhao; C. C. Lang

    2004-09-01

    We have imaged a region of ∼ 5' extent surrounding Sgr A* in the HI 21 cm-line absorption using the Very Large Array. A Gaussian decomposition of the optical depth spectra at positions within ∼ 2' (∼ 5 pc at 8.5 kpc) of Sgr A∙ detects a wide line underlying the many narrow absorption lines. The wide line has a mean peak optical depth of 0.32 ± 0.12 centered at a mean velocity of lsr = -4 ± 15 km s-1. The mean full width at half maximum is 119±42 km s-1. Such a wide line is absent in the spectra at positions beyond ∼ 2' from Sgr A*. The position-velocity diagrams in optical depth reveal that the wide line originates in various components of the circumnuclear disk (radius ∼ 1.3') surrounding Sgr A*. These components contribute to the optical depth of the wide line in different velocity ranges. The position-velocity diagrams do not reveal any diffuse feature which could be attributed to a large number of HI clouds along the line of sight to Sgr A*. Consequently, the wide line has no implications either to a global population of shocked HI clouds in the Galaxy or to the energetics of the interstellar medium as was earlier thought.

  3. New Detections of Galactic Molecular Absorption Systems toward ALMA Calibrator Sources

    Ando, Ryo; Tamura, Yoichi; Izumi, Takuma; Umehata, Hideki; Nagai, Hiroshi

    2015-01-01

    We report on Atacama Large Millimeter/submillimeter Array (ALMA) detections of molecular absorption lines in Bands 3, 6 and 7 toward four radio-loud quasars, which were observed as the bandpass and complex gain calibrators. The absorption systems, three of which are newly detected, are found to be Galactic origin. Moreover, HCO absorption lines toward two objects are detected, which almost doubles the number of HCO absorption samples in the Galactic diffuse medium. In addition, high HCO to H13CO+ column density ratios are found, suggesting that the interstellar media (ISM) observed toward the two calibrators are in photodissociation regions, which observationally illustrates the chemistry of diffuse ISM driven by ultraviolet (UV) radiation. These results demonstrate that calibrators in the ALMA Archive are potential sources for the quest for new absorption systems and for detailed investigation of the nature of the ISM.

  4. New detections of Galactic molecular absorption systems toward ALMA calibrator sources

    Ando, Ryo; Kohno, Kotaro; Tamura, Yoichi; Izumi, Takuma; Umehata, Hideki; Nagai, Hiroshi

    2016-02-01

    We report on Atacama Large Millimeter/submillimeter Array (ALMA) detections of molecular absorption lines in Bands 3, 6, and 7 toward four radio-loud quasars, which were observed as the bandpass and complex gain calibrators. The absorption systems, three of which are newly detected, are found to be Galactic origin. Moreover, HCO absorption lines toward two objects are detected, which almost doubles the number of HCO absorption samples in the Galactic diffuse medium. In addition, high HCO-to-H13CO+ column density ratios are found, suggesting that the interstellar media (ISM) observed toward the two calibrators are in photodissociation regions, which observationally illustrates the chemistry of diffuse ISM driven by ultraviolet (UV) radiation. These results demonstrate that calibrators in the ALMA Archive are potential sources for the quest for new absorption systems and for detailed investigation of the nature of the ISM.

  5. Strong clustering of high-redshift Lyman-$\\alpha$ forest absorption systems

    Fernández-Soto, A; Barcons, X; Carswell, R F; Webb, J K; Yahil, A

    1996-01-01

    We use new observations of very weak CIV absorption lines associated with high-redshift Lyman-alpha absorption systems to measure the high-redshift Lyman-alpha line two-point correlation function (TPCF). These very weak CIV absorption lines trace small-scale velocity structure that cannot be resolved by Lyman-alpha absorption lines. We find that (1) high-redshift Lyman-alpha absorption systems with N(HI) > 3.10^14 cm^{-2} are strongly clustered in redshift, (2) previous measurements of the Lyman-alpha line TPCF underestimated the actual clustering of the absorbers due to unresolved blending of overlapping velocity components, (3) the present observations are consistent with the hypothesis that clustering of Lyman-alpha absorption systems extends to lower column densities, but maybe with smaller amplitude in the correlation function, and (4) the observed clustering is broadly compatible with that expected for galaxies at z \\sim 2-3. We interpret these results as suggesting that many or most Lyman-alpha absorbe...

  6. Constraining the Variation of the Fine Structure Constant with Observations of Narrow Quasar Absorption Lines

    Songaila, A

    2014-01-01

    The unequivocal demonstration of temporal or spatial variability in a fundamental constant of nature would be of enormous significance. Recent attempts to measure the variability of the fine structure constant, alpha, over cosmological time, using high resolution spectra of high redshift quasars observed with 10m class telescopes, have produced conflicting results. We used the Many Multiplet (MM) method with Mg II and Fe II lines on very high signal-to-noise, high resolution (R = 72,000) Keck HIRES spectra of eight narrow quasar absorption systems and show, using careful wavelength calibrations, that the systematic wavelength errors are too large for previous observations to have had the sensitivity to detect such variation using this technique. We find no significant change in alpha, Delta(alpha)/alpha =(0.00 +/- 0.24) x 10^(-5), in the redshift range z=0.7-1.5. We also show that the scatter in measurements of Delta(alpha)/alpha arising from line selection can be considerably larger than assigned statistical...

  7. Occurrence and Global Properties of Narrow CIV lambda 1549 Absorption Lines in Moderate-Redshift Quasars

    Vestergaard, Marianne

    2003-01-01

    A statistical study is presented of (a) the frequency of narrow CIV lambda 1549 absorption lines in 1.5 ~50%) of narrow CIV absorbers is detected for the radio-quiet and radio-loud quasars, and a constant ~25% of all the quasars, irrespective of radio type display associated CIV absorbers stronger...... than a rest equivalent width of 0.5A. Both radio-quiet and radio-loud quasars with narrow absorption lines have systematically redder continua, especially strongly absorbed objects. There is evidence of inclination dependent dust reddening and absorption for the radio quasars. An additional key result...... is that the most strongly absorbed radio quasars have the largest radio source extent. This result is in stark contrast to a recent study of the low-frequency selected Molonglo survey in which a connection between the strength of the narrow absorbers and the (young) age of the radio source has been...

  8. Broad Absorption Line Variability in Repeat Quasar Observations from the Sloan Digital Sky Survey

    Lundgren, B F; Brunner, R J; Hall, P B; Schneider, D P; York, D G; Vanden Berk, D E; Brinkmann, J; Lundgren, Britt F.; Wilhite, Brian C.; Brunner, Robert J.; Hall, Patrick B.; Schneider, Donald P.; York, Donald G.; Berk, Daniel E. Vanden; Brinkmann, Jonathan

    2006-01-01

    We present a time-variability analysis of 29 broad absorption line quasars (BALQSOs) observed in two epochs by the Sloan Digital Sky Survey (SDSS). These spectra are selected from a larger sample of BALQSOs with multiple observations by virtue of exhibiting a broad CIV $\\lambda$1549 absorption trough separated from the rest frame of the associated emission peak by more than 3600 km s$^{-1}$. Detached troughs facilitate higher precision variability measurements, since the measurement of the absorption in these objects is not complicated by variation in the emission line flux. We have undertaken a statistical analysis of these detached-trough BALQSO spectra to explore the relationships between BAL features that are seen to vary and the dynamics of emission from the quasar central engine. We have measured variability within our sample, which includes three strongly variable BALs. We have also verified that the statistical behavior of the overall sample agrees with current model predictions and previous studies o...

  9. Observing broad-absorption line quasars with Spectrum-Rontgen-Gamma

    Singh, K.P.; Schnopper, H.W.; Westergaard, Niels Jørgen Stenfeldt

    1998-01-01

    Broad-absorption line quasars are found to have extremely weak soft X-ray emission when compared with other optically selected quasars. In the only example of PHL 5200 for which a detailed X-ray spectrum has been obtained with ASCA, strong absorption in the source appears to be responsible for the...... lack of soft Xray emission. Broad-band X-ray observations of a sample of BAL QSOs are proposed with a high throughput mission SPECTRUM-RONTGEN-GAMMA (SRG), to find out whether these sources are intrinsically weak over the entire bandwidth of X-rays or only in the soft X-rays due to absorption resulting...... from the line of sight passing through large column density clouds. Simultaneous UV observations will help to constrain the ionization state of the absorbers, and also improve the overall UV to X-ray continuum measurements in them....

  10. Voigt Profile Fitting to Quasar Absorption Lines: A Simple Approximation to the Voigt-Hjerting Function

    García, T T

    2006-01-01

    The Voigt-Hjerting function is fundamental in order to correctly model the profiles of absorption lines imprinted in the spectra of bright background sources (e.g quasars) by intervening neutral hydrogen. In this work we present a simple analytical approximation to this function in the context of intergalactic neutral hydrogen absorption-line profiles. Using basic calculus tools, we derive an expression that contains only fourth order polynomial and Gaussian functions, and that approximates this function with an accuracy better than $10^{-3}$ per cent. In connection with the absorption coefficient of intergalactic neutral hydrogen, $\\tau_{\\mathrm{H I}}(\\lambda)$, this approximation is valid for an arbitrary wavelength baseline, for column densities up to $\

  11. BROAD ABSORPTION LINE DISAPPEARANCE ON MULTI-YEAR TIMESCALES IN A LARGE QUASAR SAMPLE

    We present 21 examples of C IV broad absorption line (BAL) trough disappearance in 19 quasars selected from systematic multi-epoch observations of 582 bright BAL quasars (1.9 –1. We discuss possible origins of this connection including disk-wind rotation and changes in shielding gas.

  12. Cross section calculations of astrophysical interest. [for theories of absorption and emission lines

    Gerjuoy, E.

    1974-01-01

    Cross sections are discussed for rotational excitation associated with theories of absorption and emission lines from molecules in space with emphasis on H2CO, CO, and OH by collisions with neutral particles such H, H2, and He. The sensitivity of the Thaddeus equation for the H2CO calculation is examined.

  13. Spectro web: oscillator strength measurements of atomic absorption lines in the sun and procyon

    We update the online SpectroWeb database of spectral standard reference stars with 1178 oscillator strength values of atomic absorption lines observed in the optical spectrum of the Sun and Procyon (α CMi A). The updated line oscillator strengths are measured with best fits to the disk-integrated KPNO-FTS spectrum of the Sun observed between 4000 A and 6800 A using state-of-the-art detailed spectral synthesis calculations. A subset of 660 line oscillator strengths is validated with synthetic spectrum calculations of Procyon observed with ESO-UVES between 4700 A and 6800 A. The new log(gf)-values in SpectroWeb are improvements upon the values offered in the online Vienna Atomic Line Database (VALD). We find for neutral iron-group elements, such as Fe I, Ni I, Cr I, and Ti I, a statistically significant over-estimation of the VALD log((gf)-values for weak absorption lines with normalized central line depths below 15 %. For abundant lighter elements (e.g. Mg I and Ca I) this trend is statistically not significantly detectable, with the exception of Si I for which the log(gf)-values of 60 weak and medium-strong lines are substantially decreased to best fit the observed spectra. The newly measured log(gf)-values are available in the SpectroWeb database at http://spectra.freeshell.org, which interactively displays the observed and computed stellar spectra, together with corresponding atomic line data.

  14. A summary of transition probabilities for atomic absorption lines formed in low-density clouds

    Morton, D. C.; Smith, W. H.

    1973-01-01

    A table of wavelengths, statistical weights, and excitation energies is given for 944 atomic spectral lines in 221 multiplets whose lower energy levels lie below 0.275 eV. Oscillator strengths were adopted for 635 lines in 155 multiplets from the available experimental and theoretical determinations. Radiation damping constants also were derived for most of these lines. This table contains the lines most likely to be observed in absorption in interstellar clouds, circumstellar shells, and the clouds in the direction of quasars where neither the particle density nor the radiation density is high enough to populate the higher levels. All ions of all elements from hydrogen to zinc are included which have resonance lines longward of 912 A, although a number of weaker lines of neutrals and first ions have been omitted.

  15. CATALOG OF NARROW C IV ABSORPTION LINES IN BOSS. I. QUASARS WITH z em ≤ 2.4

    We have assembled absorption systems by visually identifying C IV λλ1548, 1551 absorption doublets in the quasar spectra of the Baryon Oscillation Spectroscopic Survey one by one. This paper is the first of the series of work. In this paper, we focus on quasars with relatively low redshifts and high signal-to-noise ratio spectra, and hence we limit our analysis to quasars with z em ≤ 2.4 and to doublets with Wr λ1548 ≥ 0.2 Å. Out of the more than 87,000 quasars in Data Release 9, we limit our search to 10,121 quasars that have the appropriate redshifts and spectra with high enough signal-to-noise ratios to identify narrow C IV absorption lines. Among them, 5442 quasars are detected to have at least one C IV λλ1548, 1551 absorption doublet. We obtain a catalog containing 8368 C IV λλ1548, 1551 absorption systems, whose redshifts are within z abs = 1.4544-2.2805. In this catalog, about 33.7% absorbers have 0.2 Å ≤Wr λ1548 < 0.5 Å, about 45.9% absorbers have 0.5 Å ≤Wr λ1548 < 1.0 Å, about 19.2% absorbers have 1.0 Å ≤Wr λ1548 < 2.0 Å, and about 1.2% absorbers have Wr λ1548 ≥ 2.0 Å

  16. Herschel observations of extra-ordinary sources: Detecting spiral arm clouds by CH absorption lines

    Qin, S -L; Comito, C; Möller, T; Rolffs, R; Müller, H S P; Belloche, A; Menten, K M; Lis, D C; Phillips, T G; Bergin, E A; Bell, T A; Crockett, N R; Blake, G A; Cabrit, S; Caux, E; Ceccarelli, C; Cernicharo, J; Daniel, F; Dubernet, M -L; Emprechtinger, M; Encrenaz, P; Falgarone, E; Gerin, M; Giesen, T F; Goicoechea, J R; Goldsmith, P F; Gupta, H; Herbst, E; Joblin, C; Johnstone, D; Langer, W D; Lord, S D; Maret, S; Martin, P G; Melnick, G J; Morris, P; Murphy, J A; Neufeld, D A; Ossenkopf, V; Pagani, L; Pearson, J C; Pérault, M; Plume, R; Salez, M; Schlemmer, S; Stutzki, J; Trappe, N; van der Tak, F F S; Vastel, C; Wang, S; Yorke, H W; Yu, S; Zmuidzinas, J; Boogert, A; Güsten, R; Hartogh, P; Honingh, N; Karpov, A; Kooi, J; Krieg, J M; Schieder, R; Diez-Gonzalez, M C; Bachille, R; Martin-Pintado, J; Baechtold, W; Olberg, M; Nordh, L H; Gill, J L; Chattopadhyay, G

    2010-01-01

    We have observed CH absorption lines ($J=3/2, N=1 \\leftarrow J=1/2, N=1$) against the continuum source Sgr~B2(M) using the \\textit{Herschel}/HIFI instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities and line widths are detected and identified. The narrower line width and lower column density clouds show `spiral arm' cloud characteristics, while the absorption component with the broadest line width and highest column density corresponds to the gas from the Sgr~B2 envelope. The observations show that each `spiral arm' harbors multiple velocity components, indicating that the clouds are not uniform and that they have internal structure. This line-of-sight through almost the entire Galaxy offers unique possibilities to study the basic chemistry of simple molecules in diffuse clouds, as a variety of different cloud classes are sampled simultaneously. We find that the linear relationship between CH and H$_2$ column dens...

  17. Absorption-line profiles in a companion spectrum of a mass-losing cool supergiant

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1992-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10 (exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  18. Absorption line profiles in a companion spectrum of a mass losing cool supergiant

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1990-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10(exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  19. The Redshift Dependence of Gamma-Ray Absorption in the Environments of Strong-Line AGNs

    Reimer, A.; /Stanford U., HEPL /KIPAC, Menlo Park

    2007-11-12

    The case of {gamma}-ray absorption due to photon-photon pair production of jet photons in the external photon environments, such as the accretion disk and the broad-line region radiation fields, of {gamma}-ray--loud active galactic nuclei (AGNs) that exhibit strong emission lines is considered. I demonstrate that this 'local opacity,' if detected, will almost unavoidably be redshift-dependent in the sub-TeV range. This introduces nonnegligible biases and complicates approaches for studying the evolution of the extragalactic background light with contemporary GeV instruments such as the Gamma-Ray Large Area Space Telescope (GLAST ), where the {gamma}-ray horizon is probed by means of statistical analysis of absorption features (e.g., the Fazio-Stecker relation) in AGN spectra at various redshifts. It particularly applies to strong-line quasars, where external photon fields are potentially involved in {gamma}-ray production.

  20. Detectability of cold streams into high-z galaxies by absorption lines

    Goerdt, Tobias; Sternberg, Amiel; Gnat, Orly; Ceverino, Daniel

    2012-01-01

    Cold gas streaming along the dark-matter filaments of the cosmic web is predicted to be the major source of fuel for disc buildup, violent disk instability and star formation in massive galaxies at high redshift. We investigate to what extent such cold gas is detectable in the extended circum-galactic environment of galaxies via Ly alpha absorption and selected low ionisation metal absorption lines. We model the expected absorption signatures using high resolution zoom-in AMR cosmological simulations. In the postprocessing, we distinguish between self-shielded gas and unshielded gas. In the self-shielded gas, which is optically thick to Lyman continuum radiation, we assume pure collisional ionisation for species with an ionisation potential greater than 13.6 eV. In the optically thin, unshielded gas these species are also photoionised by the meta-galactic radiation. In addition to absorption of radiation from background quasars, we compute the absorption line profiles of radiation emitted by the galaxy at the...

  1. A Comprehensive Study of Broad Absorption Line Quasars: I. Prevalence of HeI* Absorption Line Multiplets in Low-Ionization Objects

    Liu, Wen-Juan; Ji, Tuo; Yuan, Weimin; Wang, Ting-Gui; Jian, Ge; Shi, Xiheng; Zhang, Shaohua; Jiang, Peng; Shu, Xinwen; Wang, Huiyuan; Wang, Shu-Fen; Sun, Luming; Yang, Chenwei; Liu, Bo; Zhao, Wen

    2015-01-01

    Neutral Helium multiplets, HeI*3189,3889,10830 are very useful diagnostics to the geometry and physical conditions of the absorbing gas in quasars. So far only a handful of HeI* detections have been reported. Using a newly developed method, we detected HeI*3889 absorption line in 101 sources of a well-defined sample of 285 MgII BAL quasars selected from the SDSS DR5. This has increased the number of HeI* BAL quasars by more than one order of magnitude. We further detected HeI*3189 in 50% (52/101) quasars in the sample. The detection fraction of HeI* BALs in MgII BAL quasars is about 35% as a whole, and increases dramatically with increasing spectral signal-to-noise ratios, from 18% at S/N = 35. This suggests that HeI* BALs could be detected in most MgII LoBAL quasars, provided spectra S/N is high enough. Such a surprisingly high HeI* BAL fraction is actually predicted from photo-ionization calculations based on a simple BAL model. The result indicates that HeI* absorption lines can be used to search for BAL q...

  2. Deburring line automating system; Baritori line jidoka system

    Hiraki, H.; Oda, T. [Meidensha Corp., Tokyo (Japan)

    1994-10-18

    Automation was carried out in deburring work using robots in casting and forging processes. With an aluminum cast deburring robot system, a worker sets workpieces on two conveyors alternately, and robot performs processing them sequentially, hence the waiting time for the robot is extremely short. Three kinds of tools are exchanged by an automatic tool changer depending on the condition of burr generation. The system functions also include automatic correction of grinding stones based on measurement of their wear amount, detection of cutting tool breakage, handling irregularly large burrs by means of a tool monitoring unit, and issuing an anomaly alarm upon a worker making a mistake in workpiece selection. The steel cast deburring robot system deals with burrs inside and outside a workpiece by using a process dividing system operated by two robots. The cylinder block deburring robot system works in a line processing system, identifying eight models by using a workpiece model determining machine, and the workpiece models can be changed by a positioning device eliminating the need of set-up works. 4 figs., 4 tabs.

  3. Weak hard X-ray emission from two broad absorption line quasars observed with NuSTAR: Compton-thick absorption or intrinsic X-ray weakness?

    Luo, B.; Brandt, W. N.; Alexander, D. M.;

    2013-01-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus...

  4. The Pittsburgh Sloan Digital Sky Survey MgII Quasar Absorption-Line Survey Catalog

    Quider, Anna M; Turnshek, David A; Rao, Sandhya M; Monier, Eric M; Weyant, Anja N; Busche, Joseph R

    2011-01-01

    We present a catalog of intervening MgII quasar absorption-line systems in the redshift interval 0.36 17,000 measured MgII doublets. We also present data on the ~44,600 quasar spectra which were searched to construct the catalog, including redshift and magnitude information, continuum-normalized spectra, and corresponding arrays of redshift-dependent minimum rest equivalent widths detectable at our confidence threshold. The catalog is available on the web. A careful second search of 500 random spectra indicated that, for every 100 spectra searched, approximately one significant MgII system was accidentally rejected. Current plans to expand the catalog beyond DR4 quasars are discussed. Many MgII absorbers are known to be associated with galaxies. Therefore, the combination of large size and well understood statistics makes this catalog ideal for precision studies of the low-ionization and neutral gas regions associated with galaxies at low to moderate redshift. An analysis of the statistics of MgII absorbers ...

  5. The Pittsburgh Sloan Digital Sky Survey Mg II Quasar Absorption-line Survey Catalog

    Quider, Anna M.; Nestor, Daniel B.; Turnshek, David A.; Rao, Sandhya M.; Monier, Eric M.; Weyant, Anja N.; Busche, Joseph R.

    2011-04-01

    We present a catalog of intervening Mg II quasar absorption-line systems in the redshift interval 0.36 <= z <= 2.28. The catalog was built from Sloan Digital Sky Survey Data Release Four (SDSS DR4) quasar spectra. Currently, the catalog contains ~17, 000 measured Mg II doublets. We also present data on the ~44, 600 quasar spectra which were searched to construct the catalog, including redshift and magnitude information, continuum-normalized spectra, and corresponding arrays of redshift-dependent minimum rest equivalent widths detectable at our confidence threshold. The catalog is available online. A careful second search of 500 random spectra indicated that, for every 100 spectra searched, approximately one significant Mg II system was accidentally rejected. Current plans to expand the catalog beyond DR4 quasars are discussed. Many Mg II absorbers are known to be associated with galaxies. Therefore, the combination of large size and well understood statistics makes this catalog ideal for precision studies of the low-ionization and neutral gas regions associated with galaxies at low to moderate redshift. An analysis of the statistics of Mg II absorbers using this catalog will be presented in a subsequent paper.

  6. First Detection of HCO+ Absorption in the Magellanic System

    Murray, Claire E.; Stanimir´, Snežana; McClure-Griffiths, N. M.; Putman, M. E.; Liszt, H. S.; Wong, Tony; Richter, P.; Dawson, J. R.; Dickey, John M.; Lindner, Robert R.; Babler, Brian L.; Allison, J. R.

    2015-07-01

    We present the first detection of HCO+ absorption in the Magellanic System. Using the ATCA, we observed nine extragalactic radio continuum sources behind the Magellanic System and detected HCO+ absorption toward one source located behind the leading edge of the Magellanic Bridge. The detection is located at an LSR velocity of v=214.0+/- 0.4 {km} {{{s}}}-1, with an FWHM of {{Δ }}v=4.5+/- 1.0 {km} {{{s}}}-1, and an optical depth of τ ({{HCO}}+)=0.10+/- 0.02. Although there is abundant neutral hydrogen (H i) surrounding the sight line in position-velocity space, at the exact location of the absorber the H i column density is low, \\lt {10}20 {{cm}}-2, and there is little evidence for dust or CO emission from Planck observations. While the origin and survival of molecules in such a diffuse environment remain unclear, dynamical events such as H i flows and cloud collisions in this interacting system likely play an important role.

  7. [The Research for Trace Ammonia Escape Monitoring System Based on Tunable Diode Laser Absorption Spectroscopy].

    Zhang, Li-fang; Wang, Fei; Yu, Li-bin; Yan, Jian-hua; Cen, Ke-fa

    2015-06-01

    In order to on-line measure the trace ammonia slip of the commercial power plant in the future, this research seeks to measure the trace ammonia by using tunable diode laser absorption spectroscopy under ambient temperature and pressure, and at different temperatures, and the measuring temperature is about 650 K in the power plant. In recent years lasers have become commercially available in the near-infrared where the transitions are much stronger, and ammonia's spectroscopy is pretty complicated and the overlapping lines are difficult to resolve. A group of ammonia transitions near 4 433.5 cm(-1) in the v2 +v3 combination band have been thoroughly selected for detecting lower concentration by analyzing its absorption characteristic and considering other absorption interference in combustion gases where H2O and CO2 mole fraction are very large. To illustrate the potential for NH3 concentration measurements, predictions for NH3, H2O and CO2 are simultaneously simulated, NH3 absorption lines near 4 433.5 cm(-1) wavelength meet weaker H2O absorption than the commercial NH3 lines, and there is almost no CO2 absorption, all the parameters are based on the HITRAN database, and an improved detection limit was obtained for interference-free NH3 monitoring, this 2.25 μm band has line strengths several times larger than absorption lines in the 1.53 μm band which was often used by NH3 sensors for emission monitoring and analyzing. The measurement system was developed with a new Herriott cell and a heated gas cell realizing fast absorption measurements of high resolution, and combined with direct absorption and wavelenguh modulation based on tunable diode laser absorption spectroscopy at different temperatures. The lorentzian line shape is dominant at ambient temperature and pressure, and the estimated detectivity is approximately 0.225 x 10(-6) (SNR = 1) for the directed absorption spectroscopy, assuming a noise-equivalent absorbance of 1 x 10(-4). The heated cell

  8. PHENIX on-line systems

    Adler, S.S.; Allen, M.; Alley, G.; Amirikas, R.; Arai, Y.; Awes, T.C.; Barish, K.N.; Barta, F.; Batsouli, S.; Belikov, S.; Bennett, M.J.; Bobrek, M.; Boissevain, J.G.; Boose, S.; Britton, C.; Britton, L.; Bryan, W.L.; Cafferty, M.M.; Carey, T.A.; Chang, W.C.; Chi, C.Y.; Chiu, M.; Cianciolo, V.; Cole, B.A.; Constantin, P.; Cook, K.C.; Cunitz, H.; Desmond, E.J.; Ebisu, K.; Efremenko, Y.V.; El Chenawi, K.; Emery, M.S.; Engo, D.; Ericson, N.; Fields, D.E.; Frank, S.; Frantz, J.E.; Franz, A.; Frawley, A.D.; Fried, J.; Gannon, J.; Gee, T.F.; Gentry, R.; Giannotti, P.; Gustafsson, H.-A.; Haggerty, J.S.; Hahn, S.; Halliwell, J.; Hamagaki, H.; Hansen, A.G.; Hara, H.; Harder, J.; He, X.; Heistermann, F.; Hemmick, T.K.; Hibino, M.; Hill, J.C. E-mail: jhill@iastate.edu; Homma, K.; Jacak, B.V.; Jagadish, U.; Jia, J.; Kajihara, F.; Kametani, S.; Kamyshkov, Y.; Kandasamy, A.; Kang, J.H.; Kapustinsky, J.; Katou, K.; Kelley, M.A.; Kelly, S.; Kikuchi, J.; Kim, S.Y.; Kim, Y.G.; Kistenev, E.; Kotchetkov, D.; Kurita, K.; Lajoie, J.G.; Lenz, M.; Lenz, W.; Li, X.H.; Lin, S.; Liu, M.X.; Markacs, S.; Matathias, F.; Matsumoto, T.; Mead, J.; Mischke, R.E.; Mishra, G.C.; Moore, A.; Muniruzzamann, M.; Musrock, M.; Nagle, J.L.; Nandi, B.K.; Newby, J.; Nystrand, J.; O' Brien, E.; O' Connor, P.; Ohnishi, H.; Oskarsson, A.; Osterman, L.; Oyama, K.; Paffrath, L.; Pancake, C.E.; Pantuev, V.S.; Petridis, A.N.; Pisani, R.P.; Plagge, T.; Plasil, F.; Purschke, M.L.; Rankowitz, S.; Rao, R.; Rau, M.; Read, K.F.; Ryu, S.S.; Sakaguchi, T.; Sato, H.D.; Seto, R.; Shiina, T.; Silvermyr, D.; Simon-Gillo, J.; Simpson, M.; Sippach, W.; Skank, H.D.; Skutnik, S.; Sleege, G.A.; Smith, G.D.; Smith, M.; Stankus, P.W.; Steinberg, P.; Sugitate, T.; Sullivan, J.P.; Taketani, A.; Tamai, M.; Tanaka, Y.; Thomas, W.D.; Todd, R.; Toldo, F.; Turner, G.; Ushiroda, T.; Velkovska, J.; Hecke, H.W. van; Lith, M. van; Villatte, L.; Achen, W. von; Walker, J.W.; Wang, H.Q.; White, S.N.; Wintenberg, A.L.; Witzig, C.; Wood, L.[and others

    2003-03-01

    The PHENIX On-Line system takes signals from the Front End Modules (FEM) on each detector subsystem for the purpose of generating events for physics analysis. Processing of event data begins when the Data Collection Modules (DCM) receive data via fiber-optic links from the FEMs. The DCMs format and zero suppress the data and generate data packets. These packets go to the Event Builders (EvB) that assemble the events in final form. The Level-1 trigger (LVL1) generates a decision for each beam crossing and eliminates uninteresting events. The FEMs carry out all detector processing of the data so that it is delivered to the DCMs using a standard format. The FEMs also provide buffering for LVL1 trigger processing and DCM data collection. This is carried out using an architecture that is pipelined and deadtimeless. All of this is controlled by the Master Timing System (MTS) that distributes the RHIC clocks. A Level-2 trigger (LVL2) gives additional discrimination. A description of the components and operation of the PHENIX On-Line system is given and the solution to a number of electronic infrastructure problems are discussed.

  9. PHENIX on-line systems

    The PHENIX On-Line system takes signals from the Front End Modules (FEM) on each detector subsystem for the purpose of generating events for physics analysis. Processing of event data begins when the Data Collection Modules (DCM) receive data via fiber-optic links from the FEMs. The DCMs format and zero suppress the data and generate data packets. These packets go to the Event Builders (EvB) that assemble the events in final form. The Level-1 trigger (LVL1) generates a decision for each beam crossing and eliminates uninteresting events. The FEMs carry out all detector processing of the data so that it is delivered to the DCMs using a standard format. The FEMs also provide buffering for LVL1 trigger processing and DCM data collection. This is carried out using an architecture that is pipelined and deadtimeless. All of this is controlled by the Master Timing System (MTS) that distributes the RHIC clocks. A Level-2 trigger (LVL2) gives additional discrimination. A description of the components and operation of the PHENIX On-Line system is given and the solution to a number of electronic infrastructure problems are discussed

  10. Disk emission and absorption lines in LMXB. Note on the physical conditions of an absorbing material

    Rozanska, Agata

    2014-01-01

    We show that the continuum X-ray spectrum of 4U 1630-472 with iron absorption lines can be satisfactorily modeled by the spectrum from an accretion disk atmosphere. We performed full radiative transfer calculations using our code ATM21 to model the emission from an accretion disk surface that is seen at different viewing angles. Computed models are then fitted to the high-resolution X-ray spectra of 4U 1630-472 obtained by {\\it Suzaku} satellite. Absorption lines of highly ionized iron originating in a hot accretion-disk atmospheres are important part of the observed line profile, and can be an alternative or complementary explanation to the wind model usually favored for this type of sources. Next, assuming that absorption lines originate from the wind illuminated by X-ray central source in LMXBs, we can put constrains on the wind location only if we know the volume density number of the absorbing material. There are a few derivations of the distance to the wind in X-ray binaries. We show here, that the dens...

  11. Reionisation and High-Redshift Galaxies: The View from Quasar Absorption Lines

    Becker, George D.; Bolton, James S.; Lidz, Adam

    2015-12-01

    Determining when and how the first galaxies reionised the intergalactic medium promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing the properties of diffuse gas on galactic and intergalactic scales. In this review, we examine the multiple ways in which absorption lines trace the connection between galaxies and the intergalactic medium near the reionisation epoch. We first describe how the Ly α forest is used to determine the intensity of the ionising ultraviolet background and the global ionising emissivity budget. Critically, these measurements reflect the escaping ionising radiation from all galaxies, including those too faint to detect directly. We then discuss insights from metal absorption lines into reionisation-era galaxies and their surroundings. Current observations suggest a buildup of metals in the circumgalactic environments of galaxies over z ~ 6 to 5, although changes in ionisation will also affect the evolution of metal line properties. A substantial fraction of metal absorbers at these redshifts may trace relatively low-mass galaxies. Finally, we review constraints from the Ly α forest and quasar near zones on the timing of reionisation. Along with other probes of the high-redshift Universe, absorption line data are consistent with a relatively late end to reionisation (5.5 ≲ z ≲ 7); however, the constraints are still fairly week. Significant progress is expected to come through improved analysis techniques, increases in the number of known high-redshift quasars from optical and infrared sky surveys, large gains in sensitivity from next-generation observing facilities, and synergies with other probes of the reionisation era.

  12. Application of Fiber Bragg Grating for Determining Positions of Gas Absorption Lines

    韩文念; 汪曣; 马凤; 刘琨; 贾大功; 刘铁根; 张红霞

    2010-01-01

    Fiber Bragg grating(FBG) is used as a wavelength reference device to calibrate the position of gas absorption peak in the intracavity absorption gas sensor(ICAGS) based on erbium-doped fiberring laser.This system can detect both the reflectance spectrum of FBGs and absorption spectrum of measured gas during a single wavelength sweeping process by linearly varying the driving voltage of optic filter.The voltages corresponding to center wavelength positions of four FBGs in the spectrum are determined through ...

  13. Cloud Absorption Radiometer Autonomous Navigation System - CANS

    Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan

    2013-01-01

    CAR (cloud absorption radiometer) acquires spatial reference data from host aircraft navigation systems. This poses various problems during CAR data reduction, including navigation data format, accuracy of position data, accuracy of airframe inertial data, and navigation data rate. Incorporating its own navigation system, which included GPS (Global Positioning System), roll axis inertia and rates, and three axis acceleration, CANS expedites data reduction and increases the accuracy of the CAR end data product. CANS provides a self-contained navigation system for the CAR, using inertial reference and GPS positional information. The intent of the software application was to correct the sensor with respect to aircraft roll in real time based upon inputs from a precision navigation sensor. In addition, the navigation information (including GPS position), attitude data, and sensor position details are all streamed to a remote system for recording and later analysis. CANS comprises a commercially available inertial navigation system with integral GPS capability (Attitude Heading Reference System AHRS) integrated into the CAR support structure and data system. The unit is attached to the bottom of the tripod support structure. The related GPS antenna is located on the P-3 radome immediately above the CAR. The AHRS unit provides a RS-232 data stream containing global position and inertial attitude and velocity data to the CAR, which is recorded concurrently with the CAR data. This independence from aircraft navigation input provides for position and inertial state data that accounts for very small changes in aircraft attitude and position, sensed at the CAR location as opposed to aircraft state sensors typically installed close to the aircraft center of gravity. More accurate positional data enables quicker CAR data reduction with better resolution. The CANS software operates in two modes: initialization/calibration and operational. In the initialization/calibration mode

  14. Constraining Variable High Velocity Winds from Broad Absorption Line Quasars with Multi-Epoch Spectroscopy

    Haggard, Daryl; Green, Paul J; Aldcroft, Tom; Anderson, Scott F

    2012-01-01

    Broad absorption line (BAL) quasars probe the high velocity gas ejected by luminous accreting black holes. BAL variability timescales place constraints on the size, location, and dynamics of the emitting and absorbing gas near the supermassive black hole. We present multi-epoch spectroscopy of seventeen BAL QSOs from the Sloan Digital Sky Survey (SDSS) using the Fred Lawrence Whipple Observatory's 1.5m telescope's FAST Spectrograph. These objects were identified as BALs in SDSS, observed with Chandra, and then monitored with FAST at observed-frame cadences of 1, 3, 9, 27, and 81 days, as well as 1 and 2 years. We also monitor a set of non-BAL quasars with matched redshift and luminosity as controls. We identify significant variability in the BALs, particularly at the 1 and 2 year cadences, and use its magnitude and frequency to constrain the outflows impacting the broad absorption line region.

  15. Evidence for two spatially separated UV continuum emitting regions in the Cloverleaf broad absorption line quasar

    Sluse, D; Anguita, T; Braibant, L; Riaud, P

    2015-01-01

    Testing the standard Shakura-Sunyaev model of accretion is a challenging task because the central region of quasars where accretion takes place is unresolved with telescopes. The analysis of microlensing in gravitationally lensed quasars is one of the few techniques which can test this model, yielding to the measurement of the size and of the temperature profile of the accretion disc. We present spectroscopic observations of the gravitationally lensed broad absorption line quasar H1413+117, which reveal partial microlensing of the continuum emission that appears to originate from two separated regions, a microlensed region corresponding the compact accretion disc, and a non-microlensed region, more extended and contributing to at least 30\\% of the total UV-continuum flux. Because this extended continuum is occulted by the broad absorption line clouds, it is not associated to the host galaxy, but rather to light scattered in the neighbourhood of the central engine. We measure the amplitude of microlensing of t...

  16. Variability of Extragalactic Objects in Relation to Redshift, Color, Radio Spectral Index and Absorption Lines

    D. Basu

    2001-12-01

    Optical variability of extragalactic objects, viz., QSOs, BL Lacs and Seyfert galaxies has been monitored systematically over an appreciable period of time and a large amount of data have accumulated. The present work reports results of investigations involving statistical analysis of updated data on relationships between variability and various observed properties of the objects, viz., redshift, color indices, radio spectral index and absorption lines. It is found that at high frequencies (rest frame) radio spectral index does not change significantly with the degree of variability. However, the degree of variability depends on redshifts. On the other hand, presence or absence of absorption lines is significantly associated with variability for QSOs with larger redshifts ( > 1.0), while no such relationship exists for QSOs at smaller redshifts ( < 1.0 or other objects. Correlation between color indices and redshifts depends on the degree of variability and the sample chosen for the color index.

  17. A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Third Data Release

    Trump, J R; Brinkman, J; Fan, X; Hall, P B; Kleinman, S J; Knapp, G R; Nitta, A; Reichard, T A; Richards, G T; Schneider, D P; Vanden Berk, Daniel E; Anderson, Scott F.; Berk, Daniel E. Vanden; Fan, Xiaohui; Hall, Patrick B.; Knapp, Gillian R.; Nitta, Atsuko; Reichard, Timothy A.; Richards, Gordon T.; Schneider, Donald P.; Trump, Jonathan R.

    2006-01-01

    We present a total of 4784 unique broad absorption line quasars from the Sloan Digital Sky Survey Third Data Release. An automated algorithm was used to match a continuum to each quasar and to identify regions of flux at least 10% below the continuum over a velocity range of at least 1000 km/s in the CIV and MgII absorption regions. The model continuum was selected as the best-fit match from a set of template quasar spectra binned in luminosity, emission line width, and redshift, with the power-law spectral index and amount of dust reddening as additional free parameters. We characterize our sample through the traditional ``balnicity'' index and a revised absorption index, as well as through parameters such as the width, outflow velocity, fractional depth and number of troughs. From a sample of 16883 quasars at 1.7 \\le z \\le 4.38, we identify 4386 (26.0%) quasars with broad CIV absorption, of which 1756 (10.4%) satisfy traditional selection criteria. From a sample of 34973 quasars at 0.5 \\le z \\le 2.15, we id...

  18. Rest-frame optical properties of luminous, radio-selected, broad absorption line quasars

    Runnoe, J. C.; R Ganguly; Brotherton, M. S.; DiPompeo, M. A.

    2013-01-01

    We have obtained IRTF/SpeX spectra of eight moderate-redshift (z=0.7-2.4), radio-selected (log R*~0.4-1.9) broad absorption line (BAL) quasars. The spectra cover the rest-frame optical band. We compare the optical properties of these quasars to those of canonically radio-quiet (log R*1) quasars. With our measurements of the optical properties, particularly the Balmer emission line widths and the continuum luminosity, we have used empirical scaling relations to estimate black hole masses and E...

  19. The VLBI structure of radio-loud Broad Absorption Line quasars

    Liu, Y.; Jiang, D. R.; Gu, M.

    2016-02-01

    The nature and origin of Broad Absorption Line (BAL) quasars and their relationship to non-BAL quasars are an open question. The BAL quasars are probably normal quasars seen along a particular line of sight. Alternatively, they are young or recently refueled. The high resolution radio morphology of BAL quasars is very important to understand the radio properties of BAL quasars. We present VLBA observations at L and C bands for a sample of BAL quasars. The observations will help us to explore the VLBI radio properties, and distinguish the present models of explaining BAL phenomena.

  20. Broad absorption line (BAL) quasars as a class of low luminosity AGNs

    Kunert-Bajraszewska, M.; Ceglowski, M.; Roskowinski, C.; Gawronski, M.

    2015-01-01

    Broad absorption lines seen in some quasars prove the existence of ionized plasma outflows from the accretion disk. Outflows together with powerful jets are important feedback processes. Understanding physics behind BAL outflows might be a key to comprehend Galaxy Evolution as a whole. First radio-loud BAL quasar was discovered in 1997 and this discovery has opened new possibilities for studies of the BAL phenomena, this time on the basis of radio emission. However, information about the radi...

  1. Forest of absorption lines in quasar spectra and the structure of the Universe

    The problem of the ''forest'' at absorption lines in the spectra of quasars is discussed in the frame of the A-theory of formation and evolution of the structure of the Universe. It is assumed that the hidden mass is connected with neutrino like particles (possibly instable) with a rest mass of the order of 60-100 eV. An observational test for the hypothesis proposed is discussed

  2. What Quasars Really Look Like: Unification of the Emission and Absorption Line Regions

    Elvis, Martin

    2000-01-01

    We propose a simple unifying structure for the inner regions of quasars and AGN. This empirically derived model links together the broad absorption line (BALS), the narrow UV/X-ray ionized absorbers, the BELR, and the 5 Compton scattering/fluorescing regions into a single structure. The model also suggests an alternative origin for the large-scale bi-conical outflows. Some other potential implications of this structure are discussed.

  3. CIV Broad Absorption Line Acceleration in Sloan Digital Sky Survey Quasars

    Grier, C. J.; Brandt, W. N.; Hall, P. B.; J. R. Trump; Ak, N. Filiz; Anderson, S. F.; Green, Paul J.; Schneider, D. P.; Sun, M.; Vivek, M.; Beatty, T. G.; Brownstein, Joel R.; Roman-Lopes, Alexandre

    2016-01-01

    We present results from the largest systematic investigation of broad absorption line (BAL) acceleration to date. We use spectra of 140 quasars from three Sloan Digital Sky Survey programs to search for global velocity offsets in BALs over timescales of ~2.5-5.5 years in the quasar rest frame. We carefully select acceleration candidates by requiring monolithic velocity shifts over the entire BAL trough, avoiding BALs with velocity shifts that might be caused by profile variability. The CIV BA...

  4. Disentangling the circumnuclear environs of Centaurus A: II. On the nature of the broad absorption line

    Espada, D; Matsushita, S; Sakamoto, K; Henkel, C; Iono, D; Israel, F P; Muller, S; Petitpas, G; Pihlstroem, Y; Taylor, G B; Trung, D V

    2010-01-01

    We report on atomic gas (HI) and molecular gas (as traced by CO(2-1)) redshifted absorption features toward the nuclear regions of the closest powerful radio galaxy, Centaurus A (NGC 5128). Our HI observations using the Very Long Baseline Array allow us to discern with unprecedented sub-parsec resolution HI absorption profiles toward different positions along the 21 cm continuum jet emission in the inner 0."3 (or 5.4 pc). In addition, our CO(2-1) data obtained with the Submillimeter Array probe the bulk of the absorbing molecular gas with little contamination by emission, not possible with previous CO single-dish observations. We shed light with these data on the physical properties of the gas in the line of sight, emphasizing the still open debate about the nature of the gas that produces the broad absorption line (~55 km/s). First, the broad H I line is more prominent toward the central and brightest 21 cm continuum component than toward a region along the jet at a distance ~ 20 mas (or 0.4 pc) further from...

  5. The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability

    Grier, C. J.; Hall, P. B.; Brandt, W. N.; Trump, J. R.; Shen, Yue; Vivek, M.; Filiz Ak, N.; Chen, Yuguang; Dawson, K. S.; Denney, K. D.; Green, Paul J.; Jiang, Linhua; Kochanek, C. S.; McGreer, Ian D.; Pâris, I.; Peterson, B. M.; Schneider, D. P.; Tao, Charling; Wood-Vasey, W. M.; Bizyaev, Dmitry; Ge, Jian; Kinemuchi, Karen; Oravetz, Daniel; Pan, Kaike; Simmons, Audrey

    2015-06-01

    We report the discovery of rapid variations of a high-velocity C iv broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4σ) variability in the equivalent width (EW) of the broad (˜4000 km s-1 wide) C iv trough on rest-frame timescales as short as 1.20 days (˜29 hr), the shortest broad absorption line variability timescale yet reported. The EW varied by ˜10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of ne ≳ 3.9 × 105 cm-3. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.

  6. Transient C IV broad absorption lines in radio-detected QSOs

    Vivek, M.; Srianand, R.; Gupta, N.

    2016-01-01

    We study the transient (i.e. emerging or disappearing) C IV broad absorption line (BAL) components in 50 radio-detected QSOs using multi-epoch spectra available in Sloan Digital Sky Survey Data Release-10. We report the detection of six BALQSOs having at least one distinct transient C IV absorption component. Based on the structure function analysis of optical light curves, we suggest that the transient absorption is unlikely to be triggered by continuum variations. Transient absorption components usually have low C IV equivalent widths (10 000 km s-1) and typically occur over rest-frame time-scales >800 d. The detection rate of transient C IV absorption seen in our sample is higher than that reported in the literature. Using a control sample of QSOs, we show that this difference is most likely due to the longer monitoring time-scale of sources in our sample while the effect of small number statistics cannot be ignored. Thus, in order to establish the role played by radio jets in driving the BAL outflows, we need a larger sample of radio-detected BALs monitored over more than 3 yr in the QSO's rest frame. We also find that the transient phenomenon in radio-detected and radio-quiet BALs does not depend on any of the QSO properties, i.e. the Eddington ratio, black hole mass, bolometric luminosity and optical-to-IR colours. All this suggests that transient BAL phenomenon is simply the extreme case of BAL variability.

  7. Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars.

    Srianand, R; Chand, H; Petitjean, P; Aracil, B

    2004-03-26

    We present the results of a detailed many-multiplet analysis performed on a new sample of Mg ii systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in alpha derived from our analysis over the redshift range 0.4quasar absorption line systems. PMID:15089663

  8. Design for Manufacturing for Energy Absorption Systems

    In the typical scenario of a helicopter crash, impact with the ground is preceded by a substantially vertical drop, with the result that a seated occupant of a helicopter experiences high spinal loads and pelvic deceleration during such crash due to the sudden arresting of vertical downward motion. It has long been recognized that spinal injuries to occupants of helicopters in such crash scenario can be minimized by seat arrangements which limit the deceleration to which the seated occupant is subjected, relative to the helicopter, to a predetermined maximum, by allowing downward movement of the seated occupant relative to the helicopter, at the time of impact with the ground, under a restraining force which, over a limited range of such movement, is limited to a predetermined maximum. In practice, significant benefits, in the way of reduced injuries and reduced seriousness of injuries, can be afforded in this way in such crash situations even where the extent of such controlled vertical movement permitted by the crashworthy seat arrangement is quite limited. Important increase of accident safety is reached with the installation of crashworthy shock absorbers on the main landing gear, but this solution is mostly feasible on military helicopters with long fixed landing gear. Seats can then give high contribution to survivability. Commonly, an energy absorber is a constant load device, if one excludes an initial elastic part of the load-stroke curve. On helicopter seats, this behavior is obtained by plastic deformation of a metal component or scraping of material. In the present work the authors have studied three absorption systems, which differ in relation to their shape, their working conditions and their constructive materials. All the combinations have been analyzed for applications in VIP helicopter seats.

  9. Integrative fitting of absorption line profiles with high accuracy, robustness, and speed

    Skrotzki, Julian; Habig, Jan Christoph; Ebert, Volker

    2014-08-01

    The principle of the integrative evaluation of absorption line profiles relies on the numeric integration of absorption line signals to retrieve absorber concentrations, e.g., of trace gases. Thus, it is a fast and robust technique. However, previous implementations of the integrative evaluation principle showed shortcomings in terms of accuracy and the lack of a fit quality indicator. This has motivated the development of an advanced integrative (AI) fitting algorithm. The AI fitting algorithm retains the advantages of previous integrative implementations—robustness and speed—and is able to achieve high accuracy by introduction of a novel iterative fitting process. A comparison of the AI fitting algorithm with the widely used Levenberg-Marquardt (LM) fitting algorithm indicates that the AI algorithm has advantages in terms of robustness due to its independence from appropriately chosen start values for the initialization of the fitting process. In addition, the AI fitting algorithm shows speed advantages typically resulting in a factor of three to four shorter computational times on a standard personal computer. The LM algorithm on the other hand retains advantages in terms of a much higher flexibility, as the AI fitting algorithm is restricted to the evaluation of single absorption lines with precomputed line width. Comparing both fitting algorithms for the specific application of in situ laser hygrometry at 1,370 nm using direct tunable diode laser absorption spectroscopy (TDLAS) suggests that the accuracy of the AI algorithm is equivalent to that of the LM algorithm. For example, a signal-to-noise ratio of 80 and better typically yields a deviation of <1 % between both fitting algorithms. The properties of the AI fitting algorithm make it an interesting alternative if robustness and speed are crucial in an application and if the restriction to a single absorption line is possible. These conditions are fulfilled for the 1,370 nm TDLAS hygrometry at the

  10. The redshift number density evolution of Mg Ⅱ absorption systems

    Zhi-Fu Chen

    2013-01-01

    We make use of the recent large sample of 17 042 Mg Ⅱ absorption systems from Quider et al.to analyze the evolution of the redshift number density.Regardless of the strength of the absorption line,we find that the evolution of the redshift number density can be clearly distinguished into three different phases.In the intermediate redshift epoch (0.6 ≤ z ≤ 1.6),the evolution of the redshift number density is consistent with the non-evolution curve,however,the non-evolution curve over-predicts the values of the redshift number density in the early (z ≤ 0.6) and late (z ≥ 1.6) epochs.Based on the invariant cross-section of the absorber,the lack of evolution in the redshift number density compared to the non-evolution curve implies the galaxy number density does not evolve during the middle epoch.The fiat evolution of the redshift number density tends to correspond to a shallow evolution in the galaxy merger rate during the late epoch,and the steep decrease of the redshift number density might be ascribed to the small mass of halos during the early epoch.

  11. Digital signal processor-based high-precision on-line Voigt lineshape fitting for direct absorption spectroscopy

    Xu, Lijun; Liu, Chang; Zheng, Deyan; Cao, Zhang; Cai, Weiwei

    2014-12-01

    To realize on-line high-accuracy measurement in direct absorption spectroscopy (DAS), a system-on-chip, high-precision digital signal processor-based on-line Voigt lineshape fitting implementation is introduced in this paper. Given that the Voigt lineshape is determined by the Gauss full width at half maximum (FWHM) and Lorentz FWHM, a look-up table, which covers a range of combinations of both, is first built to achieve rapid and accurate calculation of Voigt lineshape. With the look-up table and raw absorbance data in hand, Gauss-Newton nonlinear fitting module is implemented to obtain the parameters including both the Gauss and Lorentz FWHMs, which can be used to calculate the integrated absorbance. To realize the proposed method in hardware, a digital signal processor (DSP) is adopted to fit the Voigt lineshape in a real-time DAS measurement system. In experiment, temperature and H2O concentration of a flat flame are recovered from the transitions of 7444.36 cm-1 and 7185.6 cm-1 by the DSP-based on-line Voigt lineshape fitting and on-line integral of the raw absorbance, respectively. The results show that the proposed method can not only fit the Voigt lineshape on-line but also improve the measurement accuracy compared with those obtained from the direct integral of the raw absorbance.

  12. Restarting radio activity and dust emission in radio-loud broad absorption line quasars

    Bruni, G; Montenegro-Montes, F M; Brienza, M; González-Serrano, J I

    2015-01-01

    Broad absorption line quasars (BAL QSOs) are objects showing absorption from relativistic outflows, with velocities up to 0.2c. These manifest, in about 15% of quasars, as absorption troughs on the blue side of UV emission lines, such as C iv and Mg ii. In this work, we complement the information collected in the cm band for our previously presented sample of radio loud BAL QSOs with new observations at m and mm bands. Our aim is to verify the presence of old, extended radio components in the MHz range, and probe the emission of dust (linked to star formation) in the mm domain. We observed 5 sources from our sample, already presenting hints of low-frequency emission, with the GMRT at 235 and 610 MHz. Other 17 sources (more than half the sample) were observed with bolometer cameras at IRAM-30m and APEX. All sources observed with the GMRT present extended emission at a scale of tens of kpc. In some cases these measurements allow us to identify a second component in the SED, at frequencies below 1.4 GHz, beyond ...

  13. Atlas of Absorption Lines from 0 to 17900 Cm (sup)-1

    Park, J. H.; Rothman, L. S.; Rinsland, C. P.; Pickett, H. M.; Richardson, D. J.; Namkung, J. S.

    1987-01-01

    Plots of logarithm (base 10) of absorption line strength versus wavenumber from 0 to 17900/cm(sup)-1 are shown for the 28 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO, HOCl, N2, HCN, CH3Cl, H2O2, C2H2, C2H6, PH3), which appear in the 1986 Air Force Geophysics Laboratory high-resolution transmission molecular absorption data base (HITRAN) compilation, and for O(P-3), O-18 isotopic ozone, and HO2 from the 1984 JPL compilation in the 0- to 200/cm(sup)-1 region, and infrared solar CO lines at 4500 K. Also shown are plots of logarithm (base 10) of approximate infrared absorption cross sections of 11 heavy molecules versus wavenumber. The cross-section data cover 700 to 1800/cm(sup)-1 and are included as a separate data file in the 1986 HITRAN database.

  14. Ca II absorption lines in the spectrum of the quasar pks 2020--370 due to galactic material in the group Klemola 31

    In the spectrum of the quasar PKs 2020--370 (z/sub em/ = 1.050), we find Ca II absorption lines both at near zero redshift and at z/sub abs/ = 0.02865 +- 0.00007. The latter is closely similar to the redshifts of two galaxies in the group Klemola 31, which are nearby on the plane of the sky. This observation adds to the evidence that the narrow-lined heavy-element absorption systems in quasar spectra in general arise in the extended halos of intervening galaxies

  15. Intervening Mg II absorption systems from the SDSS DR12 quasar spectra

    Raghunathan, Srinivasan; Campusano, Luis E; Söchting, Ilona K; Graham, Matthew J; Williger, Gerard M

    2016-01-01

    We present the catalogue of the Mg II absorption systems detected at a high significance level using an automated search algorithm in the spectra of quasars from the twelfth data release of the Sloan Digital Sky Survey. A total of 266,433 background quasars were searched for the presence of absorption systems in their spectra. The continuum modelling for the quasar spectra was performed using a mean filter. A pseudo-continuum derived using a median filter was used to trace the emission lines. The absorption system catalogue contains 39,694 Mg II systems detected at a 6.0, 3.0$\\sigma$ level respectively for the two lines of the doublet. The catalogue was constrained to an absorption line redshift of 0.35 $\\le$ z$_{2796}$ $\\le$ 2.3. The rest-frame equivalent width of the $\\lambda$2796 line ranges between 0.2 $\\le$ W$_r$ $\\le$ 6.2 \\AA. Using Gaussian-noise only simulations we estimate a false positive rate of 7.7 per cent in the catalogue. We measured the number density $\\partial N^{2796}/\\partial z$ of Mg II ab...

  16. Hubble Space Telescope Observations of the Broad Absorption Line Quasar PG 0946+301

    We analyze Hubble Space Telescope (HST) and ground-based spectra of the brightest broad absorption line (BAL) quasar in the UV: PG 0946+301. A detailed study of the absorption troughs as a function of velocity is presented, facilitated by the use of a new algorithm to solve for the optical depth as a function of velocity for multiplet lines. We find convincing evidence for saturation in parts of the troughs. This supports our previous assertion that saturation is common in BALs and therefore cast doubts on claims for very high metallicity in BAL flows. Because of the importance of BAL saturation we also discuss its evidence in other objects. In PG 0946+301 large differences in ionization as a function of velocity are detected, and our findings support the hypothesis that the line of sight intersects a number of flow components that combine to give the appearance of the whole trough. Based on the optical depth profiles, we develop a geometrical-kinematical model for the flow. We have positively identified 16 ions of eight elements (H i, C iii, C iv, N iii, N iv, N v, O iii, O iv, O v, O vi, Ne v, Ne viii, P v, Si iv, S v, S vi) and have probable identifications of Mg x and S iv. Unlike earlier analysis of IUE data, we find no evidence for BALs arising from excited ionic states in the HST spectrum of PG 0946+301. copyright copyright 1999. The American Astronomical Society

  17. The Role of Absorption Cooling for Reaching Sustainable Energy Systems

    Lindmark, Susanne

    2005-07-01

    This thesis focuses on the role and potential of absorption cooling in future energy systems. Two types of energy systems are investigated: a district energy system based on waste incineration and a distributed energy system with natural gas as fuel. In both cases, low temperature waste heat is used as driving energy for the absorption cooling. The main focus is to evaluate the absorption technology in an environmental perspective, in terms of reduced CO{sub 2} emissions. Economic evaluations are also performed. The reduced electricity when using absorption cooling instead of compression cooling is quantified and expressed as an increased net electrical yield. The results show that absorption cooling is an environmentally friendly way to produce cooling as it reduces the use of electrically driven cooling in the energy system and therefore also reduces global CO{sub 2} emissions. In the small-scale trigeneration system the electricity use is lowered with 84 % as compared to cooling production with compression chillers only. The CO{sub 2} emissions can be lowered to 45 CO{sub 2}/MWh{sub c} by using recoverable waste heat as driving heat for absorption chillers. However, the most cost effective cooling solution in a district energy system is a combination between absorption and compression cooling technologies according to the study. Absorption chillers have the potential to be suitable bottoming cycles for power production in distributed systems. Net electrical yields over 55 % may be reached in some cases with gas motors and absorption chillers. This small-scale system for cogeneration of power and cooling shows electrical efficiencies comparable to large-scale power plants and may contribute to reducing peak electricity demand associated with the cooling demand.

  18. The SAURON project - XVII. Stellar population analysis of the absorption line strength maps of 48 early-type galaxies

    Kuntschner, Harald; Bacon, Roland; Cappellari, Michele; Davies, Roger L; de Zeeuw, P Tim; Falcón-Barroso, Jesús; Krajnović, Davor; McDermid, Richard M; Peletier, Reynier F; Sarzi, Marc; Shapiro, Kristen L; Bosch, Remco C E van den; van de Ven, Glenn

    2010-01-01

    (Abridged) We present a stellar population analysis of the absorption line strength maps for 48 early-type galaxies from the SAURON sample. Using the line strength index maps of Hbeta, Fe5015, and Mgb, measured in the Lick/IDS system and spatially binned to a constant signal-to-noise, together with predictions from up-to-date stellar population models, we estimate the simple stellar population-equivalent (SSP-equivalent) age, metallicity and abundance ratio [alpha/Fe] over a two-dimensional field extending up to approximately one effective radius. We find a large range of SSP-equivalent ages in our sample, of which ~40% of the galaxies show signs of a contribution from a young stellar population. The most extreme cases of post-starburst galaxies, with SSP-equivalent ages of =10 Gyr) stellar populations.

  19. A High Galactic Latitude HI 21 cm-line Absorption Survey using the GMRT: I. Observations and Spectra

    Rekhesh Mohan; K. S. Dwarakanath; G. Srinivasan

    2004-09-01

    We have used the Giant Meterwave Radio Telescope (GMRT) to measure the Galactic HI 21-cm line absorption towards 102 extragalactic radio continuum sources, located at high (|| > 15°) Galactic latitudes. The Declination coverage of the present survey is ≳ -45°. With a mean rms optical depth of ∼ 0.003, this is the most sensitive Galactic HI 21-cm line absorption survey to date. To supplement the absorption data, we have extracted the HI 21-cm line emission profiles towards these 102 lines of sight from the Leiden Dwingeloo Survey of Galactic neutral hydrogen. We have carried out a Gaussian fitting analysis to identify the discrete absorption and emission components in these profiles. In this paper, we present the spectra and the components. A subsequent paper will discuss the interpretation of these results.

  20. Analysis of crystallization risk in double effect absorption refrigeration systems

    Absorption refrigeration systems are an alternative to vapor compression ones in cooling and refrigeration applications. In comparison with single effect absorption units, double effect systems have improved performance. Also, they are more available commercially than the other multi effect absorption cycles. An important challenge in the operation of such systems is the possibility of crystallization within them. This is especially true in developing air-cooled absorption systems, which are attractive because cooling tower and associated installation and maintenance issues can be avoided. Therefore, distinguishing the working conditions that may cause crystallization can be useful in the design and control of these systems. In this paper a computational model has been developed to study and compare the effects of operating parameters on crystallization phenomena in three classes of double effect lithium bromide-water absorption refrigeration systems (series, parallel and reverse parallel) with identical refrigeration capacities. It is shown that the range of operating conditions without crystallization risks in the parallel and the reverse parallel configurations is wider than those of the series flow system. - Highlights: → We study crystallization of double effect absorption refrigeration systems. → We consider series, parallel and reverse parallel cycles. → We study the effect of operating conditions on crystallization. → We choose optimum distribution ratio for parallel and reverse parallel systems. → Crystallization possibility is low in parallel and reverse parallel cycles.

  1. An Infrared Excess Identified in Radio-Loud Broad Absorption Line Quasars

    DiPompeo, M. A.; Runnoe, J. C.; Brotherton, M. S.; Myers, A. D.

    2012-01-01

    If broad absorption line (BAL) quasars represent a high covering fraction evolutionary state (even if this is not the sole factor governing the presence of BALs), it is expected that they should show an excess of mid-infrared radiation compared to normal quasars. Some previous studies have suggested that this is not the case. We perform the first analysis of the IR properties of radio-loud BAL quasars, using IR data from WISE and optical (rest-frame ultraviolet) data from SDSS, and compare th...

  2. Properties of Radio-Selected Broad Absorption-Line Quasars from the FIRST Survey

    Becker, R. H.; White, R L; Gregg, M. D.; Brotherton, M. S.; Laurent-Meuleisen, S. A.; Arav, N.

    2000-01-01

    In a spectroscopic follow-up to the VLA FIRST survey, the FIRST Bright Quasar Survey (FBQS) has found 29 radio-selected broad absorption line (BAL) quasars. This sample provides the first opportunity to study the properties of radio-selected BAL quasars. Contrary to most previous studies, we establish that a significant population of radio-loud BAL quasars exists. Radio-selected BAL quasars display compact radio morphologies and possess both steep and flat radio spectra. Quasars with low-ioni...

  3. Probing the Inner Structure of Polar Broad Absorption-Line Quasars

    Ghosh, Kajal

    2008-10-01

    We have discovered a sample of polar broad absorption-line quasars (BALQSOs). We know their inclination angles with reasonable certainty. Thus, these are the ideal objects to probe their inner structure through the X-ray studies. However, to date, we do not have a reasonably good signal-to-noise ratio X-ray spectrum of any of these objects. Here, we propose deep XMM-Newton observations of four polar BALQSOs to study the physical processes responsible for the X-ray emission, distribution of BAL clouds, wind driven mechanism, jet entrainment, etc. Finally, all these results will be used to constrain our time-dependent hydrodynamical simulations.

  4. Test and evaluation of the in-line plutonium solution K-absorption-edge densitometer at the Savannah River Plant. Phase I. Off-line testing results

    An in-line, plutonium-solution, K-edge absorption densitometer has been developed at Los Alamos and is currently undergoing test and evaluation at the Savannah River Plant (SRP). The first phase of the test and evaluation (off-line instrument calibration and solution assays) was completed, and preparations are under way to install the instrument in-line, as soon as process schedules permit. Calibration data in the design concentration range of 25 to 40 g Pu/L demonstrate routine achievement of densitometry assay precisions of 0.5% or better in 40 min. Plutonium assays at concentrations outside the calibration range were investigated in an effort to define better the limitations of the instrument and address other possible assay situations at SRP. Densitometry precisions obtained for 40-min assays range from 3% to 5 g Pu/L down to 0.4% at 70 g Pu/L. At higher plutonium concentrations, the precision deteriorated due to increasing gamma-ray absorption by the solution. In addition, with actinide concentrations above approximately 100 g/L, the assay accuracy also suffered because of enhanced small-angle scattering effects in the large sample cell. Measurements on mixed U/Pu solutions demonstrated the feasibility of accurate plutonium assays with correction for the large uranium matrix contributions being determined from the measurement data. The 239240Pu weight fractions and 241Pu/239Pu and 238Pu/239Pu isotopic ratios can be determined. In a mockup of the in-line solution plumbing system, all assay sequences, error conditions, and interlock criteria were exercised and verified to be working properly

  5. Nonlinear Absorption and Refraction in Multilevel Organic Molecular System

    LI Chun-Fei; DENG Xiao-Xu; WANG Yu-Xiao

    2000-01-01

    The nonlinear absorption and refraction in a multilevel organic molecular system is described by using the density matrix theory. The total absorptive coefficient of the system in the low-density case is equal to a linear sum of contributions from each energy level. Similarly, the total refractive index is equal to a linear sum of contributions from each energy level plus the refractive index of the vacuum. The absorption coefficient or refractive index due to each level is proportional to the population of that level, where the constant of proportionality is called the absorption cross-section or the refraction volume, respectively. The relation between the absorption cross-section and the refraction volume for each level is also given.

  6. The Properties of Intergalactic CIV Absorption II: Which Systems Are Associated With Galaxy Outflows?

    Songaila, A

    2005-01-01

    Using the extremely high S/N quasar absorption-line sample described in the first paper of the series, we investigate which intergalactic CIV absorption line systems could be directly associated with galactic outflows at z = 2 - 3.5 from an analysis of the velocity widths of the CIV absorption line systems. Only about half the systems with a peak tau(CIV) above 0.4 in the 1548 Angstrom line (roughly a column density of CIV above about 2 x 10^13 cm^-2) have velocity widths large enough to originate in this way, and very few of the weaker systems do. The median velocity full width at a tenth max is found to be 50 km/s for systems with peak tau(CIV) in the range 0.1--0.4 and 160 km/s for systems with a peak tau(CIV) in the range 0.4--3. We show that this critical value of tau(CIV) also separates systems that could be ionized by galaxy-like spectra from those in which the ionization is clearly AGN-dominated. Together the results are consistent with a picture in which almost all the lower column density, and at le...

  7. Invisible Active Galactic Nuclei. II Radio Morphologies & Five New HI 21 cm Absorption Line Detections

    Yan, Ting; Darling, Jeremy; Momjian, Emmanuel; Sharma, Soniya; Kanekar, Nissim

    2015-01-01

    We have selected a sample of 80 candidates for obscured radio-loud active galactic nuclei and presented their basic optical/near-infrared (NIR) properties in Paper 1. In this paper, we present both high-resolution radio continuum images for all of these sources and HI 21cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz VLA continuum observations find that 52 sources are compact or have substantial compact components with size 0.1 Jy at 4.9 GHz. The most compact 36 sources were then observed with the VLBA at 1.4 GHz. One definite and 10 candidate Compact Symmetric Objects (CSOs) are newly identified, a detection rate of CSOs ~3 times higher than the detection rate previously found in purely flux-limited samples. Based on possessing compact components with high flux densities, 60 of these sources are good candidates for absorption-line searches. Twenty seven sources were observed for HI 21cm absorption at their photometric or spectroscopic redshifts with only ...

  8. SDSS J1138+3517: A quasar showing remarkably variable broad absorption lines

    Wildy, Conor

    2015-01-01

    We report on the highly variable SiIV and CIV broad absorption lines in SDSS J113831.4+351725.2 across four observational epochs. Using the SiIV doublet components, we find that the blue component is usually saturated and non-black, with the ratio of optical depths between the two components rarely being 2:1. This indicates that these absorbers do not fully cover the line-of-sight and thus a simple apparent optical depth model is insufficient when measuring the true opacity of the absorbers. Tests with inhomogeneous (power-law) and pure-partial coverage (step-function) models of the absorbing SiIV optical depth predict the most un-blended doublet's component profiles equally well. However, when testing with Gaussian-fitted doublet components to all SiIV absorbers and averaging the total absorption predicted in each doublet, the upper limit of the power law index is mostly unconstrained. This leads us to favour pure partial coverage as a more accurate measure of the true optical depth than the inhomogeneous po...

  9. A Catalog of Broad Absorption Line Quasars in Sloan Digital Sky Survey Data Release 5

    Gibson, Robert R; Brandt, W N; Hall, Patrick B; Shen, Yue; Wu, Jianfeng; Anderson, Scott F; Schneider, Donald P; Berk, Daniel Vanden; Gallagher, S C; Fan, Xiaohui; York, Donald G

    2008-01-01

    We present a catalog of 5039 broad absorption line (BAL) quasars (QSOs) in the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) QSO catalog that have absorption troughs covering a continuous velocity range >= 2000 km/s. We have fit ultraviolet (UV) continua and line emission in each case, enabling us to report common diagnostics of BAL strengths and velocities in the range -25,000 to 0 km/s for SiIV $\\lambda$1400, CIV $\\lambda$1549, AlIII $\\lambda$1857, and MgII $\\lambda$2799. We calculate these diagnostics using the spectrum listed in the DR5 QSO catalog, and also for spectra from additional SDSS observing epochs when available. In cases where BAL QSOs have been observed with Chandra or XMM-Newton, we report the X-ray monochromatic luminosities of these sources. We confirm and extend previous findings that BAL QSOs are more strongly reddened in the rest-frame UV than non-BAL QSOs and that BAL QSOs are relatively X-ray weak compared to non-BAL QSOs. The observed BAL fraction is dependent on the spectral s...

  10. Discovery of Balmer Broad Absorption Lines in the Quasar LBQS 1206+1052

    Ji, Tuo; Zhou, Hongyan; Wang, Huiyuan

    2012-01-01

    We report the discovery of Balmer broad absorption lines (BALs) in the quasar LBQS 1206+1052 and present a detailed analysis of the peculiar absorption line spectrum. Besides Mg II $\\lambda \\lambda 2796, 2803$ doublet, BALs are also detected in He I* multiplet at $\\lambda \\lambda 2946, 3189, 3889$ \\AA arising from metastable helium $2^3S$ level, and in H$\\alpha$ and H$\\beta$ from excited hydrogen H I* $n=2$ level, which are rarely seen in quasar spectra. We identify two components in the BAL troughs of $\\Delta v\\sim$2000 km s$^{-1}$ width: One component shows an identical profile in H I*, \\hei* and \\mgii with its centroid blueshifted by $-v_{\\rm c}\\approx 726$ km\\ s$^{-1}$. The other component is detected in \\hei* and \\mgii with $-v_{\\rm c}\\approx 1412$ km s$^{-1}$. We estimate the column densities of H I*, He I*, and Mg II, and compare them with possible level population mechanisms. Our results favor the scenario that the Balmer BALs originate in a partially ionized region with a column density of $N_{\\rm H}...

  11. The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability

    Grier, C J; Brandt, W N; Trump, J R; Shen, Yue; Vivek, M; Ak, N Filiz; Chen, Yuguang; Dawson, K; Denney, K D; Jiang, Linhua; Kochanek, C S; McGreer, Ian D; Pâris, I; Peterson, B M; Schneider, D P; Tao, Charling; Wood-Vasey, W M; Bizyaev, Dmitry; Ge, Jian; Kinemuchi, Karen; Oravetz, Daniel; Pan, Kaike; Simmons, Audrey

    2015-01-01

    We report the discovery of rapid variations of a high-velocity CIV broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4sigma) variability in the equivalent width of the broad (~4000 km/s wide) CIV trough on rest-frame timescales as short as 1.20 days (~29 hours), the shortest broad absorption line variability timescale yet reported. The equivalent width varied by ~10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability...

  12. Fabry-Perot Absorption Line Spectroscopy of the Galactic Bar. I. Kinematics

    Rangwala, Naseem; Stanek, K Z

    2008-01-01

    We use Fabry-Perot absorption line imaging spectroscopy to measure radial velocities using the Ca II 8542 line in 3360 stars towards three lines of sight in the Milky Way's bar: Baade's Window and offset position at (l,b) ~ (+-5.0, -3.5). This sample includes 2488 bar red clump giants, 339 bar M/K-giants, and 318 disk main sequence stars. We measure the first four moments of the stellar velocity distribution of the red clump giants, and find it to be symmetric and flat-topped. We also measure the line-of-sight average velocity and dispersion of the red clump giants as a function of distance in the bar. We detect stellar streams at the near and far side of the bar with velocity difference > 30 km/s at l = +-5, but we do not detect two separate streams in Baade's Window. Our M-giants kinematics agree well with previous studies, but have dispersions systematically lower than those of the red clump giants by ~ 10 km/s. For the disk main sequence stars we measure a velocity dispersion of ~ 45 km/s for all three li...

  13. UV Absorption Line Ratios in Circumgalactic Medium at Low Redshift in Realistic Cosmological Hydrodynamic Simulations

    Cen, Renyue

    2016-01-01

    Utilizing high-resolution cosmological hydrodynamic simulations we investigate various ultra-violet absorption lines in the circumgalactic medium of star forming galaxies at low redshift, in hopes of checking and alleviating the claimed observational conundrum of the ratio of NV to OVI absorbers, among others. We find a satisfactory agreement between simulations and extant observational data with respect to the ratios of the following four line pairs examined, NV/OVI, SiIV/OVI, NIII/OVI and NII/OVI. For the pairs involving nitrogen lines, we examine two cases of nitrogen abundance, one with constant N/O ratio and the other with varying N/O ratio, with the latter motivated by theoretical considerations of two different synthetic sources of nitrogen that is empirically verified independently. Along a separate vector, for all line pairs, we examine two cases of radiation field, one with the Haardt-Madau background radiation field and the other with an additional local radiation field sourced by hot gas in the ho...

  14. Water absorption length measurement with the ANTARES optical beacon system

    ANTARES is a neutrino telescope located in the Mediterranean Sea with the aim of detecting high energy neutrinos of extra-terrestrial origin. It consists of a three dimensional array on 12 detection lines of photomultiplier tubes (PMTs) able to detect the Cherenkov light induced by muons produced in the interaction of neutrinos with the surrounding water and seabed. To reach the best angular resolution, good time and positioning calibrations are required. The propagation of Cherenkov photons strongly depends on the optical properties of the sea water, which has an impact on the reconstruction efficiency. The determination of the optical parameters, as the absorption and scattering lengths, is crucial to calculate properly the effective area and the angular resolution of the detector. The ANTARES optical beacon system consists of pulsed and fast, well controlled light sources distributed throughout the detector to carry out in situ the relative time calibration of the detector components. In this contribution we show some results on the sea water optical properties and their stability measured with the optical beacon system.

  15. Electromagnetically induced absorption in a three-resonator metasurface system.

    Zhang, Xueqian; Xu, Ningning; Qu, Kenan; Tian, Zhen; Singh, Ranjan; Han, Jiaguang; Agarwal, Girish S; Zhang, Weili

    2015-01-01

    Mimicking the quantum phenomena in metamaterials through coupled classical resonators has attracted enormous interest. Metamaterial analogs of electromagnetically induced transparency (EIT) enable promising applications in telecommunications, light storage, slow light and sensing. Although the EIT effect has been studied extensively in coupled metamaterial systems, excitation of electromagnetically induced absorption (EIA) through near-field coupling in these systems has only been sparsely explored. Here we present the observation of the EIA analog due to constructive interference in a vertically coupled three-resonator metamaterial system that consists of two bright and one dark resonator. The absorption resonance is one of the collective modes of the tripartite unit cell. Theoretical analysis shows that the absorption arises from a magnetic resonance induced by the near-field coupling of the three resonators within the unit cell. A classical analog of EIA opens up opportunities for designing novel photonic devices for narrow-band filtering, absorptive switching, optical modulation, and absorber applications. PMID:26023061

  16. Artificial neural network analysis of triple effect absorption refrigeration systems

    Hajizadeh Aghdam, A. [Department of Mechanical Engineering, Islamic Azad University (Iran, Islamic Republic of)], email: a.hajizadeh@iaukashan.ac.ir; Nazmara, H.; Farzaneh, B. [Department of Mechanical Engineering, University of Tabriz (Iran, Islamic Republic of)], email: h.nazmara@nioec.org, email: b_farzaneh_ms@yahoo.com

    2011-07-01

    In this study, artificial neural networks are utilized to predict the performance of triple effect series and parallel flow absorption refrigeration systems, with lithium bromide/water as the working fluid. Important parameters such as high generator and evaporator temperatures were varied and their effects on the performance characteristics of the refrigeration unit were observed. Absorption refrigeration systems make energy savings possible because they can use heat energy to produce cooling, in place of the electricity used for conventional vapour compression chillers. In addition, non-conventional sources of energy (such as solar, waste heat, and geothermal) can be utilized as their primary energy input. Moreover, absorption units use environmentally friendly working fluid pairs instead of CFCs and HCFCs, which affect the ozone layer. Triple effect absorption cycles were analysed. Results apply for both series and parallel flow systems. A relative preference for parallel-flow over series-flow is also shown.

  17. Limits on heavy element abundances in QSO Ly α absorption systems

    Intermediate-resolution spectra of the QSOs MCS402, Q0347 -383, Q0420 - 388, and Q2204 - 408 have been combined to yield average spectra of Lyα absorption systems with improved signal-to-noise ratios. Searches for absorption lines of a number of heavy elements were carried out with no positive detections. Limits on the heavy element ions' column densities have been determined which are in broad agreement with previous studies. The further usefulness of intermediate-resolution spectra for setting heavy element abundance limits in Lyα systems is considered. (author)

  18. On line measurement systems for calorimetric measurements

    The development of on-line measurement systems for calorimetric measurements for the last twenty years is traced and an attempt of their classification according to the automation level and hardware unification degree is undertaken. Main attention is given to the structure of variuos types of the above systems and the role of computers as a control and calculating device in the system. The methodic problems are considered in brief. Semiautomatic measurement systems for calorimetric measurements on the base of simple controllers, the systems with one or several mini- and microcomputers on-line with an experimental installation as well as the systems with various types of interface buses (CAMAC, IEEE 488, Multibus) are described. Tendencies in the development of the measurement systems related with application of microprocessors into computer and measuring engineering and possible prospects of the on-line measurement systems for calorimetric measurements as a specific variety of on-line systems for physical experiments are considered

  19. Steam Driven Triple Effect Absorption Solar Cooling System

    Yabase, Hajime; Makita, Kazuyuki

    2012-01-01

    The authors propose a solar cooling system employing a steam-driven triple effect absorption chiller as a new technique for saving CO2 emission in the air conditioning field. The absorption chiller is a cooling machine using thermal energy as a drive source, and it is ideal for utilizing solar heat. In addition, by employing a triple effect absorption chiller of high efficiency, a high energy saving effect and a significant CO2 saving effect can be expected. As a result of studies, it has bee...

  20. Wavelength Modulation Absorption Spectroscopy Using a Frequency-Quadruped Current-Modulated System

    A wavelength modulation absorption spectrometry (WMAS) with a frequency-quadruped system is demonstrated. The frequency-quadruped system consists of a two-frequency doubled external enhancement cavity with KNO3 and BBO crystals, and a current-modulated 906-nm single mode external cavity diode laser (ECDL), which generates the tunable wavelength modulated radiation at 226.7 nm used to detect the NO absorption line that belongs to the combined Q22(10.5) and QR12(10.5) lines of 7(0, 0) band within the A2Σ+ – X2II electronic transition system. The 1st, 2nd and 3rd harmonic spectra are accomplished to show that it is possible to detect samples using the frequency quadruped system combined with the WMAS technique that can find practical applicability in the future

  1. CHANDRA VIEW OF THE WARM-HOT INTERGALACTIC MEDIUM TOWARD 1ES 1553+113: ABSORPTION-LINE DETECTIONS AND IDENTIFICATIONS. I

    Nicastro, F.; Zappacosta, L. [Osservatorio Astronomico di Roma-INAF, Via di Frascati 33, I-00040 Monte Porzio Catone, RM (Italy); Elvis, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-04, Cambridge, MA 02138 (United States); Krongold, Y. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Mexico City Mexico (Mexico); Mathur, S.; Gupta, A. [Ohio State University, Columbus, OH (United States); Danforth, C.; Shull, J. M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Barcons, X. [Instituto de Fisica de Cantabria (CSIC-UC), E-39005 Santander (Spain); Borgani, S. [Dipartimento di Astronomia dell' Universita di Trieste, Via G.B. Tiepolo 11, I-34131 Trieste (Italy); Branchini, E. [Dipartimento di Fisica ' ' E. Amaldi' ' , Universita degli Studi ' ' Roma Tre' ' , via della Vasca Navale 84, I-00146 Roma (Italy); Cen, R. [Princeton University Observatory, Princeton, NJ 08544 (United States); Dave, R. [Astronomy Department, University of Arizona, Tucson, AZ 85721 (United States); Kaastra, J. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA, Utrecht (Netherlands); Paerels, F. [Columbia Astrophysics Laboratory and Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Piro, L. [INAF-IAPS, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy); Takei, Y. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

    2013-06-01

    We present the first results from our pilot 500 ks Chandra Low Energy Transmission Grating Large Program observation of the soft X-ray brightest source in the z {approx}> 0.4 sky, the blazar 1ES 1553+113, aimed to secure the first uncontroversial detections of the missing baryons in the X-rays. We identify a total of 11 possible absorption lines, with single-line statistical significances between 2.2{sigma} and 4.1{sigma}. Six of these lines are detected at high single-line statistical significance (3.6 {<=} {sigma} {<=} 4.1), while the remaining five are regarded as marginal detections in association with either other X-ray lines detected at higher significance and/or far-ultraviolet (FUV) signposts. Three of these lines are consistent with metal absorption at z {approx_equal} 0, and we identify them with Galactic O I and C II. The remaining eight lines may be imprinted by intervening absorbers and are all consistent with being high-ionization counterparts of FUV H I and/or O VI intergalactic medium signposts. In particular, five of these eight possible intervening absorption lines (single-line statistical significances of 4.1{sigma}, 4.1{sigma}, 3.9{sigma}, 3.8{sigma}, and 2.7{sigma}), are identified as C V and C VI K{alpha} absorbers belonging to three WHIM systems at z{sub X} = 0.312, z{sub X} = 0.237, and (z{sub X} ) = 0.133, which also produce broad H I (and O VI for the z{sub X} = 0.312 system) absorption in the FUV. For two of these systems (z{sub X} = 0.312 and 0.237), the Chandra X-ray data led the a posteriori discovery of physically consistent broad H I associations in the FUV (for the third system the opposite applies), so confirming the power of the X-ray-FUV synergy for WHIM studies. The true statistical significances of these three X-ray absorption systems, after properly accounting for the number of redshift trials, are 5.8{sigma} (z{sub X} = 0.312; 6.3{sigma} if the low-significance O V and C V K{beta} associations are considered), 3.9{sigma} (z

  2. Chandra View of the Warm-hot Intergalactic Medium toward 1ES 1553+113: Absorption-line Detections and Identifications. I.

    Nicastro, F.; Elvis, M.; Krongold, Y.; Mathur, S.; Gupta, A.; Danforth, C.; Barcons, X.; Borgani, S.; Branchini, E.; Cen, R.; Davé, R.; Kaastra, J.; Paerels, F.; Piro, L.; Shull, J. M.; Takei, Y.; Zappacosta, L.

    2013-06-01

    We present the first results from our pilot 500 ks Chandra Low Energy Transmission Grating Large Program observation of the soft X-ray brightest source in the z >~ 0.4 sky, the blazar 1ES 1553+113, aimed to secure the first uncontroversial detections of the missing baryons in the X-rays. We identify a total of 11 possible absorption lines, with single-line statistical significances between 2.2σ and 4.1σ. Six of these lines are detected at high single-line statistical significance (3.6 X-ray lines detected at higher significance and/or far-ultraviolet (FUV) signposts. Three of these lines are consistent with metal absorption at z ~= 0, and we identify them with Galactic O I and C II. The remaining eight lines may be imprinted by intervening absorbers and are all consistent with being high-ionization counterparts of FUV H I and/or O VI intergalactic medium signposts. In particular, five of these eight possible intervening absorption lines (single-line statistical significances of 4.1σ, 4.1σ, 3.9σ, 3.8σ, and 2.7σ), are identified as C V and C VI Kα absorbers belonging to three WHIM systems at zX = 0.312, zX = 0.237, and langzX rang = 0.133, which also produce broad H I (and O VI for the zX = 0.312 system) absorption in the FUV. For two of these systems (zX = 0.312 and 0.237), the Chandra X-ray data led the a posteriori discovery of physically consistent broad H I associations in the FUV (for the third system the opposite applies), so confirming the power of the X-ray-FUV synergy for WHIM studies. The true statistical significances of these three X-ray absorption systems, after properly accounting for the number of redshift trials, are 5.8σ (zX = 0.312; 6.3σ if the low-significance O V and C V Kβ associations are considered), 3.9σ (zX = 0.237), and 3.8σ (langzX rang = 0.133), respectively.

  3. Broad absorption line (BAL) quasars as a class of low luminosity AGNs

    Kunert-Bajraszewska, M; Roskowinski, C; Gawronski, M

    2015-01-01

    Broad absorption lines seen in some quasars prove the existence of ionized plasma outflows from the accretion disk. Outflows together with powerful jets are important feedback processes. Understanding physics behind BAL outflows might be a key to comprehend Galaxy Evolution as a whole. First radio-loud BAL quasar was discovered in 1997 and this discovery has opened new possibilities for studies of the BAL phenomena, this time on the basis of radio emission. However, information about the radio structures, orientation and age of BAL quasars is still very limited due to weak radio emission and small sizes of these objects. Our high-resolution radio survey of a sample of BAL quasars aims to increase our knowledge about these objects. In this article, we present some conclusions arising from our research.

  4. Origin and nature of Radio-Loud Broad Absorption Line Quasars. A multi-wavelength study

    Bruni, Gabriele

    2012-01-01

    RESUMEN: El origen de los cuásares con líneas anchas de absorción (BAL QSOs, del acrónimo en inglés Broad Absorption Line Quasars) es un tema todavía en discusión. Representando aproximadamente un 20% de la población de QSOs, estos objetos muestran líneas de absorción muy anchas en su espectro óptico/UV que están generadas por flujos de material que emerge con velocidades de hasta 0.2c. No existe consenso sobre el origen de este gas causante de las absorciones, ni del mecanismo que lo acelera...

  5. Fast outflows in broad absorption line quasars and their connection with CSS/GPS sources

    Bruni, G; Montenegro-Montes, F M; Brienza, M; González-Serrano, J I

    2015-01-01

    Broad absorption line quasars are among the objects presenting the fastest outflows. The launching mechanism itself is not completely understood. Models in which they could be launched from the accretion disk, and then curved and accelerated by the effect of the radiation pressure, have been presented. We conducted an extensive observational campaign, from radio to optical band, to collect information about their nature and test the models present in the literature, the main dichotomy being between a young scenario and an orientation one. We found a variety of possible orientations, morphologies, and radio ages, not converging to a particular explanation for the BAL phenomenon. From our latest observations in the m- and mm-band, we obtained an indication of a lower dust abundance with respect to normal quasars, thus suggesting a possible feedback process on the host galaxy. Also, in the low-frequency regime we confirmed the presence of CSS components, sometime in conjunction with a GPS one already detected at...

  6. Isotopic ratios at z=0.68 from molecular absorption lines toward B 0218+357

    Wallstrom, S H J; Guelin, M

    2016-01-01

    Isotopic ratios of heavy elements are a key signature of the nucleosynthesis processes in stellar interiors. The contribution of successive generations of stars to the metal enrichment of the Universe is imprinted on the evolution of isotopic ratios over time. We investigate the isotopic ratios of carbon, nitrogen, oxygen, and sulfur through millimeter molecular absorption lines arising in the z=0.68 absorber toward the blazar B 0218+357. We find that these ratios differ from those observed in the Galactic interstellar medium, but are remarkably close to those in the only other source at intermediate redshift for which isotopic ratios have been measured to date, the z=0.89 absorber in front of PKS1830-211. The isotopic ratios in these two absorbers should reflect enrichment mostly from massive stars, and they are indeed close to the values observed toward local starburst galaxies. Our measurements set constraints on nucleosynthesis and chemical evolution models.

  7. Fine Structure of the R Absorption Lines of Cr3+ in Antiferromagnetic Dysprosium Aluminum Garnet

    Aoyagi, Kiyoshi; Kajiura, Masako; Sugano, Satoru

    1981-11-01

    The absorption spectrum of a Cr3+ ion in an antiferromagnetic disprosium aluminum garnet with the Néel temperature TN of 2.5 K, is measured in the red region between 1.7 K and 4.2 K. It is shown that the fine structure of the R1 and R2 lines at 1.7 K can be explained by using an effective Hamiltonian for the t2g3 2E excited state of Cr3+ in the surrounding of the ordered Dy3+ spins. The gross feature of the observed temperature dependence of the fine structure is shown to be reproduced by assuming appropriate exchange interactions of Cr3+ with Dy3+.

  8. Graphical expression of thermodynamic characteristics of absorption process in ammonia-water system

    Fortelný Zdeněk

    2012-04-01

    Full Text Available The adiabatic sorption is very interesting phenomenon that occurs when vapor of refrigerant is in contact with unsaturated liquid absorbent-refrigerant mixture and exchange of heat is forbid between the system and an environment. This contribution introduces new auxiliary lines that enable correct position determination of the adiabatic sorption process in the p-T-x diagram of ammoniawater system. The presented auxiliary lines were obtained from common functions for fast calculation of water-ammonia system properties. Absorption cycles designers often utilize p-t-x diagrams of working mixtures for first suggestion of new absorption cycles. The p-t-x diagrams enable fast correct determination of saturate states of liquid (and gaseous mixtures of refrigerants and absorbents. The working mixture isn’t only at saturated state during a real working cycle. If we know pressure and temperature of an unsaturated mixture, exact position determination is possible in the p-t-x diagrams too.

  9. Graphical expression of thermodynamic characteristics of absorption process in ammonia-water system

    Pospíšil, Jiří; Fortelný, Zdeněk

    2012-04-01

    The adiabatic sorption is very interesting phenomenon that occurs when vapor of refrigerant is in contact with unsaturated liquid absorbent-refrigerant mixture and exchange of heat is forbid between the system and an environment. This contribution introduces new auxiliary lines that enable correct position determination of the adiabatic sorption process in the p-T-x diagram of ammoniawater system. The presented auxiliary lines were obtained from common functions for fast calculation of water-ammonia system properties. Absorption cycles designers often utilize p-t-x diagrams of working mixtures for first suggestion of new absorption cycles. The p-t-x diagrams enable fast correct determination of saturate states of liquid (and gaseous) mixtures of refrigerants and absorbents. The working mixture isn't only at saturated state during a real working cycle. If we know pressure and temperature of an unsaturated mixture, exact position determination is possible in the p-t-x diagrams too.

  10. FR-II Broad Absorption Line Quasars and the Life Cycle of Quasars

    Gregg, M D; Becker, R H; de Vries, W

    2006-01-05

    By combining the Sloan Digitized Sky Survey Third Data Release quasar list with the VLA FIRST survey, we have identified five objects having both broad absorption lines in their optical spectra and FR-II radio morphologies. We identify an additional example of this class from the FIRST Bright Quasar Survey, J1408+3054. Including the original FR-II-BAL object, J1016+5209, brings the number of such objects to eight. These quasars are relatively rare; finding this small handful has required the 45,000-large quasar sample of SDSS. The FR-II-BAL quasars exhibit a significant anti-correlation between radio-loudness and the strength of the BAL features. This is easily accounted for by the evolutionary picture in which quasars emerge from cocoons of BAL-producing material which stifle the development of radio jets and lobes. There is no such simple explanation for the observed properties of FR-II-BALs in the unification-by-orientation model of quasars. The rarity of the FR-II-BAL class implies that the two phases do not coexist for very long in a single quasar, perhaps less than 10{sup 5} years, with the combined FR-II, high ionization broad absorption phase being even shorter by another factor of 10 or more.

  11. High-resolution absorption spectroscopy of the OH 2Pi 3/2 ground state line

    Wiesemeyer, Helmut; Heyminck, Stefan; Karl, Jacobs; Menten, Karl; Neufeld, David; Requena-Torres, Miguel Angel; Stutzki, Jürgen; 10.1051/0004-6361/201218915

    2012-01-01

    The chemical composition of the interstellar medium is determined by gas phase chemistry, assisted by grain surface reactions, and by shock chemistry. The aim of this study is to measure the abundance of the hydroxyl radical (OH) in diffuse spiral arm clouds as a contribution to our understanding of the underlying network of chemical reactions. Owing to their high critical density, the ground states of light hydrides provide a tool to directly estimate column densities by means of absorption spectroscopy against bright background sources. We observed onboard the SOFIA observatory the 2Pi3/2, J = 5/2 3/2 2.5 THz line of ground-state OH in the diffuse clouds of the Carina-Sagittarius spiral arm. OH column densities in the spiral arm clouds along the sightlines to W49N, W51 and G34.26+0.15 were found to be of the order of 10^14 cm^-2, which corresponds to a fractional abundance of 10^-7 to 10^-8, which is comparable to that of H_2O. The absorption spectra of both species have similar velocity components, and the...

  12. Gamma-Gamma Absorption in the Broad Line Region Radiation Fields of Gamma-Ray Blazars

    Boettcher, Markus

    2016-01-01

    The expected level of gamma-gamma absorption in the Broad Line Region (BLR) radiation field of gamma-ray loud Flat Spectrum Radio Quasars (FSRQs)is evaluated as a function of the location of the gamma-ray emission region. This is done self-consistently with parameters inferred from the shape of the spectral energy distribution (SED) in a single-zone leptonic EC-BLR model scenario. We take into account all geometrical effects both in the calculation of the gamma-gamma opacity and the normalization of the BLR radiation energy density. As specific examples, we study the FSRQs 3C279 and PKS 1510-089, keeping the BLR radiation energy density at the location of the emission region fixed at the values inferred from the SED. We confirm previous findings that the optical depth due to $\\gamma\\gamma$ absorption in the BLR radiation field exceeds unity for both 3C279 and PKS 1510-089 for locations of the gamma-ray emission region inside the inner boundary of the BLR. It decreases monotonically, with distance from the cen...

  13. THE STELLAR INITIAL MASS FUNCTION IN EARLY-TYPE GALAXIES FROM ABSORPTION LINE SPECTROSCOPY. II. RESULTS

    The spectral absorption lines in early-type galaxies contain a wealth of information regarding the detailed abundance pattern, star formation history, and stellar initial mass function (IMF) of the underlying stellar population. Using our new population synthesis model that accounts for the effect of variable abundance ratios of 11 elements, we analyze very high quality absorption line spectra of 38 early-type galaxies and the nuclear bulge of M31. These data extend to 1 μm and they therefore include the IMF-sensitive spectral features Na I, Ca II, and FeH at 0.82 μm, 0.86 μm, and 0.99 μm, respectively. The models fit the data well, with typical rms residuals ∼stars, are derived for individual galaxies. We find that the IMF becomes increasingly bottom-heavy with increasing velocity dispersion and [Mg/Fe]. At the lowest dispersions and [Mg/Fe] values the derived IMF is consistent with the Milky Way (MW) IMF, while at the highest dispersions and [Mg/Fe] values the derived IMF contains more low-mass stars (is more bottom-heavy) than even a Salpeter IMF. Our best-fit (M/L)stars values do not exceed dynamically based M/L values. We also apply our models to stacked spectra of four metal-rich globular clusters in M31 and find an (M/L)stars that implies fewer low-mass stars than a MW IMF, again agreeing with dynamical constraints. We discuss other possible explanations for the observed trends and conclude that variation in the IMF is the simplest and most plausible.

  14. THE INTRINSIC FRACTIONS AND RADIO PROPERTIES OF LOW-IONIZATION BROAD ABSORPTION LINE QUASARS

    Low-ionization (Mg II, Fe II, and Fe III) broad absorption line quasars (LoBALs) probe a relatively obscured quasar population and could be at an early evolutionary stage for quasars. We study the intrinsic fractions of LoBALs using the Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey, and Faint Images of the Radio Sky at Twenty cm survey. We find that the LoBAL fractions of the near-infrared (NIR) and radio samples are approximately 5-7 times higher than those measured in the optical sample. This suggests that the fractions measured in the NIR and radio bands are closer to the intrinsic fractions of the populations, and that the optical fractions are significantly biased due to obscuration effects, similar to high-ionization broad absorption line quasars (HiBALs). Considering a population of obscured quasars that do not enter the SDSS, which could have a much higher LoBAL fraction, we expect that the intrinsic fraction of LoBALs could be even higher. We also find that the LoBAL fractions decrease with increasing radio luminosities, again, similarly to HiBALs. In addition, we find evidence for increasing fractions of LoBALs toward higher NIR luminosities, especially for FeLoBALs with a fraction of ∼18% at MKs< -31 mag. This population of NIR-luminous LoBALs may be at an early evolutionary stage of quasar evolution. To interpret the data, we use a luminosity-dependent model for LoBALs that yields significantly better fits than those from a pure geometric model.

  15. FIRST 0747+2739 A FIRST\\/2MASS Quasar with an Overabundance of C IV Absorption Systems

    Richards, G T; Becker, R H; White, R L; Richards, Gordon T.; Gregg, Michael D.; Becker, Robert H.; White, Richard L.

    2002-01-01

    We present a Keck ESI spectrum of FIRST 074711.2+273904, a K=15.4 quasar with redshift 4.11 that is detected by both FIRST and 2MASS. The spectrum contains at least 14 independent C IV absorption systems longward of the Ly-alpha forest. These systems are found over a path length of Delta z = 0.984, constituting one of the highest densities per unit redshift of C IV absorption ever observed. One of the C IV systems is trough-like and resembles a weak BAL-type outflow. Two of the C IV are ``associated'' absorption systems with |v|3000 km/s, eight are either resolved or require multiple discrete systems to fit the line profiles. In addition to C IV absorption, there are two low-ionization Mg II absorption systems along with two damped Ly-alpha systems, at least one of which may be a C IV system. The overdensity of C IV absorption spans a redshift range of Delta z=1. Superclusters along the line of sight are unlikely to cause an overdensity stretching over such a long redshift path, thus the absorption may be an ...

  16. Electromagnetically induced absorption in a three-resonator metasurface system

    Zhang, Xueqian; Xu, Ningning; Qu, Kenan; Tian, Zhen; Singh, Ranjan; Han, Jiaguang; Agarwal, Girish S.; Zhang, Weili

    2015-01-01

    Mimicking the quantum phenomena in metamaterials through coupled classical resonators has attracted enormous interest. Metamaterial analogs of electromagnetically induced transparency (EIT) enable promising applications in telecommunications, light storage, slow light and sensing. Although the EIT effect has been studied extensively in coupled metamaterial systems, excitation of electromagnetically induced absorption (EIA) through near-field coupling in these systems has only been sparsely ex...

  17. Magellan LDSS3 emission confirmation of galaxies hosting metal-rich Lyman α absorption systems

    Straka, Lorrie A.; Johnson, Sean; York, Donald G.; Bowen, David V.; Florian, Michael; Kulkarni, Varsha P.; Lundgren, Britt; Péroux, Celine

    2016-06-01

    Using the Low Dispersion Survey Spectrograph 3 at the Magellan II Clay Telescope, we target candidate absorption host galaxies detected in deep optical imaging (reaching limiting apparent magnitudes of 23.0-26.5 in g, r, i, and z filters) in the fields of three QSOs, each of which shows the presence of high metallicity, high N_{H I} absorption systems in their spectra (Q0826-2230: zabs = 0.9110, Q1323-0021: zabs = 0.7160, Q1436-0051: zabs = 0.7377, 0.9281). We confirm three host galaxies at redshifts 0.7387, 0.7401, and 0.9286 for two of the Lyman α absorption systems (one with two galaxies interacting). For these systems, we are able to determine the star formation rates (SFRs); impact parameters (from previous imaging detections); the velocity shift between the absorption and emission redshifts; and, for one system, also the emission metallicity. Based on previous photometry, we find these galaxies have L > L*. The [O II] SFRs for these galaxies are in the range 11-25 M⊙ yr-1 (uncorrected for dust), while the impact parameters lie in the range 35-54 kpc. Despite the fact that we have confirmed galaxies at 50 kpc from the QSO, no gradient in metallicity is indicated between the absorption metallicity along the QSO line of sight and the emission line metallicity in the galaxies. We confirm the anticorrelation between impact parameter and N_{H I} from the literature. We also report the emission redshift of five other galaxies: three at zem > zQSO, and two (L < L*) at zem < zQSO not corresponding to any known absorption systems.

  18. Catalog of Narrow Mg II Absorption Lines in the Baryon Oscillation Spectroscopic Survey

    Chen, Zhi-Fu; Gu, Qiu-Sheng; Chen, Yan-Mei

    2015-12-01

    Using the Data Release 9 Quasar spectra from the Baryonic Oscillation Spectroscopic Survey, which does not include quasar spectra from the Sloan Digital Sky Survey Data Release 7, we detect narrow Mg ii λλ2796, 2803 absorption doublets in the spectral data redward of 1250 Å (quasar rest frame) until the red wing of the Mg ii λ2800 emission line. Our survey is limited to quasar spectra with a median signal-to-noise ratio ≥slant 4 pixel-1 in the surveyed spectral region, resulting in a sample that contains 43,260 quasars. We have detected a total of 18,598 Mg ii absorption doublets with 0.2933 ≤ zabs ≤ 2.6529. About 75% of absorbers have an equivalent width at rest frame of {W}rλ 2796≥slant 1 \\mathringA . About 75% of absorbers have doublet ratios ({DR}={W}rλ 2796/{W}rλ 2803) in the range of 1 ≤ DR ≤ 2, and about 3.2% lie outside the range of 1 - σDR ≤ DR ≤ 2 + σDR. We characterize the detection false positives/negatives by the frequency of detected Mg ii absorption doublets in the limits of the S/N of the spectral data. The S/N = 4.5 limit is assigned a completeness fraction of 53% and tends to be complete when the S/N is greater than 4.5. The redshift number densities of all of the detected Mg ii absorbers moderately increase from z ≈ 0.4 to z ≈ 1.5, which parallels the evolution of the cosmic star formation rate density. Limiting our investigation to those quasars whose emission redshift can be determined from narrow emission lines, the relative velocities (β) of Mg ii absorbers have a complex distribution which probably consists of three classes of Mg ii absorbers: (1) cosmologically intervening absorbers; (2) environmental absorbers that reside within the quasar host galaxies or galaxy clusters; (3) quasar outflow absorbers. After subtracting contributions from cosmologically intervening absorbers and environmental absorbers, the β distribution of the Mg iiabsorbers might mainly be contributed by the quasar outflow absorbers and

  19. Comment on "Limits on the Time Variation of the Electromagnetic Fine-Structure Constant in the Low Energy Limit from Absorption Lines in the Spectra of Distant Quasars"

    Murphy, Michael T; Flambaum, Victor V

    2007-01-01

    In their Letter [Phys. Rev. Lett. 92, 121302 (2004)] (also [Astron. Astrophys. 417, 853 (2004)]), Srianand et al. analysed optical spectra of heavy-element species in 23 absorption systems along background quasar sight-lines, reporting limits on relative variations in the fine-structure constant: da/a=(-0.06+/-0.06) x 10^{-5}. Here we demonstrate basic flaws in their analysis, using the same data and absorption profile fits, which led to spurious values of da/a and significantly underestimated uncertainties. We conclude that these data and fits offer no stringent test of previous evidence for a varying alpha.

  20. Variable Reddening and Broad Absorption Lines in the Narrow-line Seyfert 1 Galaxy WPVS 007: an Origin in the Torus

    Leighly, Karen M; Grupe, Dirk; Terndrup, Donald M; Komossa, S

    2015-01-01

    We report the discovery of an occultation event in the low-luminosity narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert with longer timescale variability, these observations place strong constraints on the nature and location of the absorbing material. Swift monitoring has revealed a secular decrease since ~2010 accompanied by flattening of the optical and UV photometry that suggests variable reddening. Analysis of four Hubble Space Telescope COS observations since 2010, including a Director's Discretionary time observation during the occultation, shows that the broad-absorption-line velocity offset and the CIV emission-line width both decrease as the reddening increases. The occultation dynamical timescale, the BAL variability dynamical timescale, and the density of the BAL gas show that both the reddening material and the broad-absorption-line gas are consistent with an origin in the torus. These observations can be explained by a scenario in which the torus is clumpy with variabl...

  1. C IV Broad Absorption Line Acceleration in Sloan Digital Sky Survey Quasars

    Grier, C. J.; Brandt, W. N.; Hall, P. B.; Trump, J. R.; Filiz Ak, N.; Anderson, S. F.; Green, Paul J.; Schneider, D. P.; Sun, M.; Vivek, M.; Beatty, T. G.; Brownstein, Joel R.; Roman-Lopes, Alexandre

    2016-06-01

    We present results from the largest systematic investigation of broad absorption line (BAL) acceleration to date. We use spectra of 140 quasars from three Sloan Digital Sky Survey programs to search for global velocity offsets in BALs over timescales of ≈2.5–5.5 years in the quasar rest frame. We carefully select acceleration candidates by requiring monolithic velocity shifts over the entire BAL trough, avoiding BALs with velocity shifts that might be caused by profile variability. The C iv BALs of two quasars show velocity shifts consistent with the expected signatures of BAL acceleration, and the BAL of one quasar shows a velocity-shift signature of deceleration. In our two acceleration candidates, we see evidence that the magnitude of the acceleration is not constant over time; the magnitudes of the change in acceleration for both acceleration candidates are difficult to produce with a standard disk-wind model or via geometric projection effects. We measure upper limits to acceleration and deceleration for 76 additional BAL troughs and find that the majority of BALs are stable to within about 3% of their mean velocities. The lack of widespread acceleration/deceleration could indicate that the gas producing most BALs is located at large radii from the central black hole and/or is not currently strongly interacting with ambient material within the host galaxy along our line of sight.

  2. The parsec-scale structure of radio-loud broad absorption line quasars

    Bruni, G; Mack, K -H; Montenegro-Montes, F M; González-Serrano, J I; Holt, J; Jiménez-Luján, F

    2013-01-01

    Broad Absorption Line Quasars (BAL QSOs) belong to a class of objects not well-understood as yet. Their UV spectra show BALs in the blue wings of the UV resonance lines, due to ionized gas with outflow velocities up to 0.2 c. They can have radio emission difficult to characterize, and that needs to be studied at various wavelengths and resolutions. We aim at studying the pc-scale properties of their synchrotron emission, and in particular at determining their core properties. We performed observations in Very Long Baseline Interferometry (VLBI) technique, using both the European VLBI Network (EVN) at 5 GHz, and the Very Long Baseline Array (VLBA) at 5 and 8.4 GHz to map the pc-scale structure of the brightest radio-loud objects of our sample, allowing a proper morphological interpretation. A variety of morphologies have been found: 9 BAL QSOs on a total of 11 observed sources have a resolved structure. Core-jet, double and symmetric objects are present, suggesting different orientations. In some cases the sou...

  3. Direct absorption and transfer of cesium 137 in a simplified fresh water supply line

    Experimentally the transfer of Cesium 137 through the supply line: Daphnia Magna Straus→Lebistes Reticulatus Peters→Anguilla Anguilla L. starting from water at 50μCi/l is studied. In the direct transfer water→organisms, the three links used have a concentration factor comprised between 2 and 4. The organisms retain a maximum of 0,3% of the water's radioactivity. The muscular mass of the eel represents 60% of the animal's total activity. The biological period is close to 400 days indicating that the fixed Cesium is strongly retained. Through the absorption of a contaminated meal, the Lebists, after two days, retain 67% of the activities of the Daphnies and the Eels, after seven days, 39% of the activity of the Guppys. At the end of the experiment, the Eels contaminated by food 3.500. It takes 63 meals for the level of contamination due to food to equal that due to water. The concentration factors measured in situ are always distinctly higher than those obtained in the laboratory. The experiment proves the possibilities of concentration through the food supply line

  4. AN INFRARED EXCESS IDENTIFIED IN RADIO-LOUD BROAD ABSORPTION LINE QUASARS

    If broad absorption line (BAL) quasars represent a high-covering-fraction evolutionary state (even if this is not the sole factor governing the presence of BALs), it is expected that they should show an excess of mid-infrared radiation compared to normal quasars. Some previous studies have suggested that this is not the case. We perform the first analysis of the IR properties of radio-loud BAL quasars, using IR data from WISE and optical (rest-frame ultraviolet) data from SDSS, and compare the BAL quasar sample with a well-matched sample of unabsorbed quasars. We find a statistically significant excess in the mid- to near-infrared luminosities of BAL quasars, particularly at rest-frame wavelengths of 1.5 and 4 μm. Our sample was previously used to show that BALs are observed along many lines of sight toward quasars, but with an overabundance of more edge-on sources, suggesting that orientation factors into the appearance of BALs. The evidence here—of a difference in IR luminosities between BAL quasars and unabsorbed quasars—can be ascribed to evolution. This suggests that a merging of the current BAL paradigms is needed to fully describe the class.

  5. Magnetic Turbulence and Line Broadening in Simulations of Lyman-Alpha Absorption

    Gurvich, Alex; Burkhart, Blakesley K.; Bird, Simeon

    2016-01-01

    We use the Illustris cosmological AREPO simulations to study the effects of gas turbulence and magnetic fields on measurements from the Lyman-Alpha forest. We generate simulated Lyman-Alpha spectra and plot the distributions of Column Density (CDD) and Doppler Width (b) both by adhering to the canonical method of fitting Voigt profiles to absorption lines and by directly measuring the column density and equivalent widths from snapshot data .We investigate the effects of additional unresolved gas turbulence in Illustris by adding an additional broadening term to the line profiles to mimic turbulent broadening. When we do this, we find a measurable effect in the CDD and an offset in the mean of the b distribution corresponding to the additional turbulence. We also compare different MHD runs in AREPO we find that the CDD can measurably differentiate between magnetic seed field at redshifts as low as z=0.1, but we do not find that the b distribution is affected at a detectable level. Our work suggests that the effects of turbulence and magnetic fields from z=2-0.1 can potentially be measured with these diagnostics. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  6. Quasar broad absorption line variability measurements using reconstructions of un-absorbed spectra

    Wildy, Conor; Allen, James T

    2013-01-01

    We present a two-epoch SDSS and Gemini/GMOS+WHT/ISIS variability study of 50 broad absorption line quasars of redshift range 1.9 < z < 4.2, containing 38 Si IV and 59 C IV BALs and spanning rest-frame time intervals of approximately 10 months to 3.7 years. We find that 35/50 quasars exhibit one or more variable BALs, with 58% of Si IV and 46% of C IV BALs showing variability across the entire sample. On average, Si IV BALs show larger fractional change in BAL pseudo equivalent width than C IV BALs, as referenced to an unabsorbed continuum+emission-line spectrum constructed using non-negative matrix factorisation. No correlation is found between BAL variability and quasar luminosity, suggesting that ionizing continuum changes do not play a significant role in BAL variability (assuming the gas is in photoionization equilibrium with the ionizing continuum). A subset of 14 quasars have one variable BAL from each of Si IV and C IV with significant overlap in velocity space and for which variations are in the...

  7. Mooring Line for an Oceanographic Buoy System

    National Oceanic and Atmospheric Administration, Department of Commerce — A mooring line for an oceanographic buoy system includes four sections. The first section is a protected cable that is connectable to the buoy. The second section...

  8. Theoretical Study of New Combined Absorption-Ejector Refrigeration System

    Abed, A. M.; Sopian, K.; Alghoul, M. A.; Al-Shamani, A. N.; Ruslan, M. H.; Mat, S.

    2015-09-01

    An improved system of the new combined single stage absorption cycle operated with NH3/H2O as working fluid was performed. In order to enhance performance the cycle a new configuration of absorption system was utilized. The performances of two configurations of the combined absorption cycle were compared; a) with common solution heat exchanger and b) divided the streamline of solution heat exchanger to recover the internal heat. Based on the analysis, it has been shown that the second configuration a significant reduction of the required generator and absorber loads by about 20% and 17% respectively, with increased coefficient of performance (COP) about 12% compared to the first configuration. This improvement in the overall COP is found due to improve energy utilization efficiency significantly.

  9. Atmospheric profiling via satellite to satellite occultations near water and ozone absorption lines for weather and climate

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Stovern, M.; Sammler, K.; Reed, H.; Erickson, D.; McCormick, C.; Griggs, E.

    2016-05-01

    Significantly reducing weather and climate prediction uncertainty requires global observations with substantially higher information content than present observations provide. While GPS occultations have provided a major advance, GPS observations of the atmosphere are limited by wavelengths chosen specifically to minimize interaction with the atmosphere. Significantly more information can be obtained via satellite to satellite occultations made at wavelengths chosen specifically to characterize the atmosphere. Here we describe such a system that will probe cm- and mmwavelength water vapor absorption lines called the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS). Profiling both the speed and absorption of light enables ATOMMS to profile temperature, pressure and humidity simultaneously, which GPS occultations cannot do, as well as profile clouds and turbulence. We summarize the ATOMMS concept and its theoretical performance. We describe field measurements made with a prototype ATOMMS instrument and several important capabilities demonstrated with those ground based measurements including retrieving temporal variations in path-averaged water vapor to 1%, in clear, cloudy and rainy conditions, up to optical depths of 17, remotely sensing turbulence and determining rain rates. We conclude with a vision of a future ATOMMS low Earth orbiting satellite constellation designed to take advantage of synergies between observational needs for weather and climate, ATOMMS unprecedented orbital remote sensing capabilities and recent cubesat technological innovations that enable a constellation of dozens of very small spacecraft to achieve many critical, but as yet unfulfilled, monitoring and forecasting needs.

  10. Hydrogen Balmer beta: The separation between line peaks for plasma electron density diagnostics and self-absorption test

    We propose a diagnostic technique for the measurement of plasma electron number density, Ne, based on the wavelength separation between peaks, ΔλPS, of hydrogen Balmer beta line, Hβ. In favor of the proposed diagnostic technique we demonstrate high sensitivity of ΔλPS on Ne and low sensitivity on plasma elementary processes and plasma parameters that may distort the line profile. These properties of ΔλPS enable reliable Ne plasma diagnostics in the presence of considerable self-absorption. On the basis of available theoretical data tables for the Hβ line profiles, simple Ne=f(ΔλPS) formulas are proposed. Their validity is experimentally confirmed in a low initial pressure pulsed discharge for the Ne range of (0.2–7)⁎1023 m−3. The agreement of the proposed formulas with another diagnostic technique is well within 10%. In addition, the difference in Ne values obtained from peak separation and from the Hβ line width is successfully used as a self-absorption test for line profile. - Highlights: • Separation between peaks of Hβ line proposed for electron density diagnostics. • Derived formulas for peak separations versus electron density. • Formulas tested in high electron density low pressure pulsed arc. • Applications of formulas in optically thick plasmas proven. • Method for hydrogen Balmer beta line self-absorption testing proposed

  11. JAERI Tokai on-line network system

    Computer network ''JAERI Tokai On-line Network System'' has been developed to provide laboratory local users with means of on-line data processing for various data arising from nuclear instrumentation. The on-line network system consists of a large-scale main computer and many minicomputers, and message switching store and forward type packet exchangers (PEX) to connect the computers and constitute a network. Several PEXs are connected in mesh structure through communication lines to give a self-controlled network (PEX Network). A PEX control system program, which controls each PEX, consists of a real time monitor and a PEX control program which works under the real time monitor. Described are functions of the real time monitor, specifications of monitor control routines and a PEX control program, and also structure of control tables. (auth.)

  12. Simultaneous multi-element atomic absorption system using photodiode array detector

    A photodiode array (PDA) detector-multichannel analyser (MCA) system has been coupled to a flame and a graphite furnace atomiser and tested for simultaneous multielement atomic absorption analysis. Multielement hollow cathode lamps (HCL) are used as light source. Spectral lines are dispersed through a spectrograph with triple gratings and detected by a 25.4 mm PDA detector consisting of 1024 elements. The optical MCA system is capable of recording multiple spectra spanned by the spectrograph/PDA. The transmitted intensity spectra obtained for the standard and analyte solutions during flame or graphite furnace atomisation are converted to absorbance spectra using the MCA software provided. Results from the comparison studies show that the linear range and sensitivities for Ni-Co-Fe and Cu-Cr obtained from the simultaneous measurements are within the same order of magnitudes as those from conventional single element determinations using photomultiplier tube detection. The study also shows that non-atomic absorption can be readily corrected by a two-line method where non-atomic absorption lines can be chosen from the spectra recorded simultaneously. The proposed system has been evaluated for the determination of trace elements using NBS standard reference water SRM 1643b

  13. Stellar Surface Magneto-Convection as a Source of Astrophysical Noise. I. Multi-component Parameterisation of Absorption Line Profiles

    Cegla, H M; Watson, C A; Mathioudakis, M

    2012-01-01

    We outline our techniques to characterise photospheric granulation as an astrophysical noise source. A four component parameterisation of granulation is developed that can be used to reconstruct stellar line asymmetries and radial velocity shifts due to photospheric convective motions. The four components are made up of absorption line profiles calculated for granules, magnetic intergranular lanes, non-magnetic intergranular lanes, and magnetic bright points at disc centre. These components are constructed by averaging Fe I $6302 \\mathrm{\\AA}$ magnetically sensitive absorption line profiles output from detailed radiative transport calculations of the solar photosphere. Each of the four categories adopted are based on magnetic field and continuum intensity limits determined from examining three-dimensional magnetohydrodynamic simulations with an average magnetic flux of $200 \\mathrm{G}$. Using these four component line profiles we accurately reconstruct granulation profiles, produced from modelling 12 x 12 Mm$...

  14. Solar evacuated tube collector: absorption chiller systems simulation

    Leflar, J.A.; Duff, W.S.

    1977-12-01

    A residential air conditioning system incorporating an Arkla Solaire absorption chiller and Corning Glass Works evacuated tube collectors is simulated and the design parameters studied. Mathematical models of the evacuated tube collector and Arkla absorption chiller based on experimental results of the components have been created and incorporated into a complete system simulation. The chiller model includes transient start-up effects and the evacuated tube collector model includes numerous optical effects. A standard Arkla chiller in a humid climate (Washington, D.C.) and an Arkla unit with a modified charge for dry climates (Fort Collins, Colorado) are studied. Design parameters considered include the use of chilled water storage to reduce transient start-up effects of the absorption unit, the effects of removing heat from the solar system for preheating service hot water, the use of a tempering valve to prevent over-firing of the absorption unit in dry climates, and solar storage sizing considerations. The study results and conclusions are used to specify a cooling system design.

  15. Backscatter absorption gas imaging systems and light sources therefore

    Kulp, Thomas Jan; Kliner, Dahv A. V.; Sommers, Ricky; Goers, Uta-Barbara; Armstrong, Karla M.

    2006-12-19

    The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

  16. New aspects of absorption line formation in intervening turbulent clouds; 3, The inverse problem in the study of H+D profiles

    Levshakov, S A; Takahara, F

    1997-01-01

    A new method, based on a Reverse Monte Carlo technique and aimed at the inverse problem in the analysis of interstellar (intergalactic) absorption lines is presented. We consider the process of line formation in media with a stochastic velocity field accounting for the effects of a finite correlation length (mesoturbulence). This approach generalizes the standard microturbulent approximation, which is commonly used to model the formation of absorption spectra in turbulent media. The method allows to estimate from an observed spectrum both, the physical parameters of the absorbing gas, and an appropriate structure of the velocity distribution parallel to the line of sight. The procedure is applied to a template H+D Ly-alpha profile which reproduces the Burles and Tytler [BT] spectrum of the quasar Q 1009+2956 with the DI Ly-alpha line seen at the redshift z = 2.504. The results obtained favor a low D/H ratio in this particular absorption system, although the inferred upper limit for the hydrogen isotopic ratio...

  17. Space Launch System Base Heating Test: Tunable Diode Laser Absorption Spectroscopy

    Parker, Ron; Carr, Zak; MacLean, Matthew; Dufrene, Aaron; Mehta, Manish

    2016-01-01

    This paper describes the Tunable Diode Laser Absorption Spectroscopy (TDLAS) measurement of several water transitions that were interrogated during a hot-fire testing of the Space Launch Systems (SLS) sub-scale vehicle installed in LENS II. The temperature of the recirculating gas flow over the base plate was found to increase with altitude and is consistent with CFD results. It was also observed that the gas above the base plate has significant velocity along the optical path of the sensor at the higher altitudes. The line-by-line analysis of the H2O absorption features must include the effects of the Doppler shift phenomena particularly at high altitude. The TDLAS experimental measurements and the analysis procedure which incorporates the velocity dependent flow will be described.

  18. Strong MgII Absorption Systems in QSOs from the Sloan Digital Sky Survey Early Data Release

    Nestor, D B; Turnshek, D A; Fürst, E; Nestor, Daniel B.; Rao, Sandhya; Turnshek, David; Furst, Eric

    2002-01-01

    We have constructed samples of low-ionization metal absorption-line systems selected for the strength of their MgII lambda2796 lines from the SDSS EDR. There are 640 absorption systems in our unbiased sample with lambda2796 REW > 1.0 A detected at 5 sigma and with redshifts 0.37 < z < 2.27. This sample is an order of magnitude larger than previous similarly selected samples. In this contribution, we present preliminary results on the statistical properties of the sample.

  19. Metal Absorption Profiles from the Central Star of the Planetary Nebula M27 (NGC 6583, PN GO60.8-036, the Dumbbell) -- Photospheric and Nebular Line Identifications

    McCandliss, S R; Candliss, Stephan. R. Mc; Kruk, Jeffrey

    2006-01-01

    High resolution spectra of the hot central star of the planetary nebula (CSPN) M27, acquired with the Far Ultraviolet Spectroscopic Explorer (\\FUSE), have revealed an unusually rich set of narrow molecular hydrogen absorption features. This object is also unique in that the velocity of nebular absorption features are cleanly separated from the velocity of the intervening interstellar medium. These features blend with and in many cases obscure atomic features. We have developed a continuum model of the CSPN including atomic and molecular hydrogen absorption. Using this model we have identified and tabulated the metal lines as arising from either photospheric, nebular and/or non-nebular velocity systems. We find the nebular outflow and ionization balance to be stratified with high ionization states favored at low velocity and low ionization states favored at high velocity. Neutrals and molecules are found at a velocity that marks the transistion between these two regimes. These observations are a challenge to t...

  20. JAERI Tokai on-line network system

    Computer network ''JAERI Tokai On-line Network System'' has been developed to provide laboratory local users with means of on-line data processing for various data arising from nuclear instrumentation. The on-line network system consists of a large-scale host computer at the computing center and minicomputers, and PEX network to connect the computers. Described in this report are software specifications of Front End Processor (FEP), which is attached to the central host computer to interface with the PEX network. FEP is provided with 16 sockets through which terminal laboratory systems are simultaneously connected. The FEP system facilitates the data transmission between the network and the central host computer: FACOM 230/75, according to an established PEX network protocol and ETAM-NCO network control rule of FACOM 230/75, respectively. (author)

  1. Absolute absorption on the potassium D lines:theory and experiment

    Hanley, Ryan K; Hughes, Ifan G; Cornish, Simon L

    2015-01-01

    We present a detailed study of the absolute Doppler-broadened absorption of a probe beam scanned across the potassium D lines in a thermal vapour. Spectra using a weak probe were measured on the 4S $\\rightarrow$ 4P transition and compared to the theoretical model of the electric susceptibility detailed by Zentile et al. (2015) in the code named ElecSus. Comparisons were also made on the 4S $\\rightarrow$ 5P transition with an adapted version of ElecSus. This is the first experimental test of ElecSus on an atom with a ground state hyperfine splitting smaller than that of the Doppler width. An excellent agreement was found between ElecSus and experimental measurements at a variety of temperatures with rms errors of $\\sim 10^{-3}$. We have also demonstrated the use of ElecSus as an atomic vapour thermometry tool, and present a possible new measurement technique of transition decay rates which we predict to have a precision $\\sim$ 3 kHz.

  2. The Compact Structure of Radio-Loud Broad Absorption Line Quasars

    Liu, Y; Wang, T G; Xie, F G

    2008-01-01

    We present the results of EVN+MERLIN VLBI polarization observations of 8 Broad Absorption Line (BAL) quasars at 1.6 GHz, including 4 LoBALs and 4 HiBALs with either steep or flat spectra on VLA scales. Only one steep-spectrum source, J1122+3124, shows two-sided structure on the scale of 2 kpc. The other four steep-spectrum sources and three flat-spectrum sources display either an unresolved image or a core-jet structure on scales of less than three hundred parsecs. In all cases the marginally resolved core is the dominant radio component. Linear polarization in the cores has been detected in the range of a few to 10 percent. Polarization, together with high brightness temperatures (from 2*10^9-5*10^10 K), suggest a synchrotron origin for the radio emission. There is no apparent difference in the radio orphologies or polarization between low-ionization and high-ionization BAL QSOs nor between flat- and steep-spectrum sources. We discuss the orientation of BAL QSOs with both flat and steep spectra, and consider...

  3. The compact structure of radio-loud broad absorption line quasars

    Liu, Y.; Jiang, D. R.; Wang, T. G.; Xie, F. G.

    2008-11-01

    We present the results of EVN+MERLIN very long baseline interferometry (VLBI) polarization observations of eight broad absorption line (BAL) quasars at 1.6 GHz, including four low-ionization BAL quasars (LoBALs) and four high-ionization BAL quasars (HiBALs) with either steep or flat spectra on Very Large Array (VLA) scales. Only one steep-spectrum source, J1122+3124, shows two-sided structure on the scale of 2 kpc. The other four steep-spectrum sources and three flat-spectrum sources display either an unresolved image or a core-jet structure on scales of less than 300 pc. In all cases, the marginally resolved core is the dominant radio component. Linear polarization in the cores has been detected in the range of a few to 10 per cent. Polarization, together with high brightness temperatures (from 2 × 109 to 5 × 1010K), suggests a synchrotron origin for the radio emission. There is no apparent difference in the radio morphologies or polarization between low-ionization and high-ionization BAL quasi-stellar objects (QSOs) or between flat- and steep-spectrum sources. We discuss the orientation of BAL QSOs with both flat and steep spectra, and consider a possible evolutionary scenario for BAL QSOs. In this scenario, BAL QSOs are probably a young population of radio sources that are compact steep spectrum or GHz peaked radio source analogues at the low end of radio power.

  4. Absorption lines from magnetically-driven winds in X-ray binaries

    Chakravorty, S; Ferreira, J; Henri, G; Belmont, R; Clavel, M; Corbel, S; Rodriguez, J; Coriat, M; Drappeau, S; Malzac, J

    2016-01-01

    High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines from disk winds which seem to be equatorial. Winds occur in the Softer (disk-dominated) states of the outburst and are less prominent or absent in the Harder (power-law dominated) states. We use self-similar magneto-hydrodynamic (MHD) accretion-ejection models to explain the disk winds in BHBs. In our models, the density at the base of the outflow from the accretion disk is not a free parameter, but is determined by solving the full set of dynamical MHD equations. Thus the physical properties of the outflow are controlled by the global structure of the disk. We studied different MHD solutions characterized by different values of (a) the disk aspect ratio ($\\varepsilon$) and (b) the ejection efficiency ($p$). We use two kinds of MHD solutions depending on the absence (cold solution) or presence (warm solution) of heating at the disk surface. Such heating could be from e.g. dissipation of energy due to MHD turbul...

  5. CIV Broad Absorption Line Acceleration in Sloan Digital Sky Survey Quasars

    Grier, C J; Hall, P B; Trump, J R; Ak, N Filiz; Anderson, S F; Green, Paul J; Schneider, D P; Sun, M; Vivek, M; Beatty, T G; Brownstein, Joel R; Roman-Lopes, Alexandre

    2016-01-01

    We present results from the largest systematic investigation of broad absorption line (BAL) acceleration to date. We use spectra of 140 quasars from three Sloan Digital Sky Survey programs to search for global velocity offsets in BALs over timescales of ~2.5-5.5 years in the quasar rest frame. We carefully select acceleration candidates by requiring monolithic velocity shifts over the entire BAL trough, avoiding BALs with velocity shifts that might be caused by profile variability. The CIV BALs of two quasars show velocity shifts consistent with the expected signatures of BAL acceleration, and the BAL of one quasar shows a velocity-shift signature of deceleration. In our two acceleration candidates, we see evidence that the magnitude of the acceleration is not constant over time; the magnitudes of the change in acceleration for both acceleration candidates are difficult to produce with a standard disk-wind model or via geometric projection effects. We measure upper limits to acceleration and deceleration for ...

  6. Radio Through X-ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars

    Gallagher, S C; Brandt, W N; Egami, E; Hines, D C; Priddey, R S

    2007-01-01

    We have compiled the largest sample of multiwavelength spectral energy distributions (SEDs) of Broad Absorption Line (BAL) quasars to date, from the radio to the X-ray. We present new Spitzer MIPS (24, 70, and 160 micron) observations of 38 BAL quasars in addition to data from the literature and public archives. In general, the mid-infrared properties of BAL quasars are consistent with those of non-BAL quasars of comparable luminosity. In particular, the optical-to-mid-infrared luminosity ratios of the two populations are indistinguishable. We also measure or place upper limits on the contribution of star formation to the far-infrared power. Of 22 (57%) upper limits, seven quasars have sufficiently sensitive constraints to conclude that star formation likely contributes little (<20%) to their far-infrared power. The 17 BAL quasars (45%) with detected excess far-infrared emission likely host hyperluminous starbursts with L_fir,SF=10^{13-14} L_sun. Mid-infrared through X-ray composite BAL quasar SEDs are pre...

  7. Classifying Broad Absorption Line Quasars: Metrics, Issues and a New Catalogue Constructed from SDSS DR5

    Scaringi, S; Knigge, C; Goad, M R

    2009-01-01

    We apply a recently developed method for classifying broad absorption line quasars (BALQSOs) to the latest QSO catalogue constructed from Data Release 5 of the Sloan Digital Sky Survey. Our new hybrid classification scheme combines the power of simple metrics, supervised neural networks and visual inspection. In our view the resulting BALQSO catalogue is both more complete and more robust than all previous BALQSO catalogues, containing 3552 sources selected from a parent sample of 28,421 QSOs in the redshift range 1.7

  8. Multi-Sightline Observation of Narrow Absorption Lines in Lensed Quasar SDSS J1029+2623

    Misawa, Toru; Charlton, Jane C; Eracleous, Michael; Chartas, George; Bauer, Franz E; Inada, Naohisa; Uchiyama, Hisakazu

    2016-01-01

    We exploit the widely-separated images of the lensed quasar SDSS J1029+2623 ($z_{em}$=2.197, $\\theta =22^{\\prime\\prime}\\!\\!.5$) to observe its outflowing wind through two different sightlines. We present an analysis of three observations, including two with the Subaru telescope in 2010 February (Misawa et al. 2013) and 2014 April (Misawa et al. 2014), separated by 4 years, and one with the Very Large Telescope, separated from the second Subaru observation by $\\sim$2 months. We detect 66 narrow absorption lines (NALs), of which 24 are classified as intrinsic NALs that are physically associated with the quasar based on partial coverage analysis. The velocities of intrinsic NALs appear to cluster around values of $v_{ej}$ $\\sim$ 59,000, 43,000, and 29,000 km/s, which is reminiscent of filamentary structures obtained by numerical simulations. There are no common intrinsic NALs at the same redshift along the two sightlines, implying that the transverse size of the NAL absorbers should be smaller than the sightline...

  9. Analysis of the influence of various effects on frequency shifts of the acetylene saturated absorption lines

    Dong Lei; Zhang Lei; Dou Hai-Peng; Yin Wang-Bao; Jia Suo-Tang

    2008-01-01

    Frequency shifts of the acetylene saturated absorption lines at 1.5μm with temperature,gas pressure and laser power have been investigated in detail.The second-order Doppler effect,the recoil effect,the Zeeman effect,the pressure shift and the power shift are taken into consideration.The magnitudes of those shifts caused by various effects are evaluated.In order to reproduce the stability of 5.7 x 10-14 obtained by Edwards,all necessary conditions are given.The results show that when there is a larger external magnetic field,the Zeeman shift could not be neglected,so that the shield should be employed.And the design of a long cavity is advantageous to reduce the influence of the second-order Doppler effect.The results also show that at least ±2.5°C temperature control for cavity can effectively prevent several effects and improve the frequency stability.

  10. Metal Absorption Lines as Probes of the Intergalactic Medium Prior to the Reionization Epoch

    Furlanetto, S; Furlanetto, Steven; Loeb, Abraham

    2003-01-01

    Winds from star-forming galaxies provide the most promising explanation for the enrichment of the intergalactic medium with heavy elements. Theoretical and observational arguments indicate that the pollution may have occurred at z > 6; however, direct observational tests of such a scenario are needed. We model starburst winds in the high-redshift universe and find that the fraction of space filled by enriched material varies strongly with the assumed star formation efficiency f_* and the fraction of supernova energy powering each wind, f_esc. We show that metals carried by these winds can be seen in absorption against bright background sources, such as quasars or gamma-ray bursts, in narrow lines with characteristic equivalent widths ~0.5 < W < 5 Angstrom. We argue that a substantial fraction of the metals in high-redshift winds are likely to reside in low ionization states (CII, OI, SiII, and FeII), but higher ionization states (CIV and SiIV) could also provide useful probes of the winds. The number of...

  11. Economic Performance Optimization of an Absorption Cooling System under Uncertainty

    Gebreslassie, Berhane H.; Guillén-Gosálbez, Gonzalo; Jiménez, Laureano; Boer, Dieter

    2009-01-01

    Abstract Many of the strategies devised so far to address the optimization of energy systems are deterministic approaches that rely on estimated data. However, in real world applications there are many sources of uncertainty that introduce variability into the decision-making problem. Within this general context, we propose a novel approach to address the design of absorption cooling systems under uncertainty in the energy cost. As opposed to other approaches that optimize the expe...

  12. A High Galactic Latitude HI 21 cm-line Absorption Survey using the GMRT: II. Results and Interpretation

    Rekhesh Mohan; K. S. Dwarakanath; G. Srinivasan

    2004-09-01

    We have carried out a sensitive high-latitude (|| > 15°) HI 21 cm-line absorption survey towards 102 sources using the GMRT. With a 3 detection limit in optical depth of ∼ 0.01, this is the most sensitive HI absorption survey. We detected 126 absorption features most of which also have corresponding HI emission features in the Leiden Dwingeloo Survey of Galactic neutral Hydrogen. The histogram of random velocities of the absorption features is well-fit by two Gaussians centered at lsr ∼ 0 km s−1 with velocity dispersions of 7.6 ± 0.3 km s-1 and 21 ± 4 km s-1 respectively. About 20% of the HI absorption features form the larger velocity dispersion component. The HI absorption features forming the narrow Gaussian have a mean optical depth of 0.20 ± 0.19, a mean HI column density of (1.46 ± 1.03) × 1020 cm-2, and a mean spin temperature of 121 ± 69 K. These HI concentrations can be identified with the standard HI clouds in the cold neutral medium of the Galaxy. The HI absorption features forming the wider Gaussian have a mean optical depth of 0.04 ± 0.02, a mean HI column density of (4.3 ± 3.4)× 1019 cm-2, and a mean spin temperature of 125 ± 82 K. The HI column densities of these fast clouds decrease with their increasing random velocities. These fast clouds can be identified with a population of clouds detected so far only in optical absorption and in HI emission lines with a similar velocity dispersion. This population of fast clouds is likely to be in the lower Galactic Halo.

  13. Performance of a compact solar absorption cooling system

    This paper describes the performance of a compact solar absorption system. Purpose of compact solar is collector, generator and condenser in one unit. At present, two types of absorption cooling systems are marketed: the lithium bromide-water system and the ammonia-water system. In the lithium bromide-water system, water vapor is the refrigerant and ammonia water system where ammonia is the refrigerant. In addition, the ammonia-water system requires higher generator temperature 120oC to 150oC than a flat-plate solar collector can provide without special techniques. The lithium bromide-water system operates satisfactorily at a generator temperature of 75oC to 100oC, achievable by a flat-plate collector. The lithium bromide-water system also has a higher COP than the ammonia-water system. The disadvantage of the lithium bromide-water systems is that the evaporators cannot operate at temperature below 0oC since the refrigerant is water. The Coefficient of Performance (COP) system is 0.62 and the concentration of LiBr-H2O is 50%

  14. Updated correlation of the absorption line blackbody distribution function for H2O based on the HITEMP2010 database

    The absorption line blackbody distribution function (ALBDF) was developed for use in global methods such as the SLW and FSK models that integrate the radiative transfer equation over the absorption coefficient rather than wavenumber. A widely used method of representing the ALBDF efficiently is a correlation in the form of a hyperbolic tangent function originally proposed by Denison and Webb. This paper reports on the generation of new coefficients to be used in the correlation for H2O using the recently released high temperature database, HITEMP2010. The updated correlation is valid for an expanded temperature range, from 400 to 3000 K, made possible by the new database. The accuracy of the new coefficients is tested and compared against the previous correlations through calculations of total emissivity and the Planck mean absorption coefficient. Solutions of the radiative transfer equation in homogeneous one-dimensional media have been performed with the SLW method using the updated ALBDF, and are compared to rigorous line-by-line calculations. The updated correlation performs very well in these calculations and shows excellent accuracy compared to the line-by-line benchmark predictions. Comparisons made with the previous coefficients show that updating the correlation was necessary in order to obtain accurate calculations. -- Highlights: ► HITEMP2010 was used to update the absorption line blackbody distribution function. ► Hyperbolic tangent form used previously was maintained. ► Temperature ceiling was extended from 2500 K up to 3000 K. ► Calculations using the updated correlation demonstrate its accuracy. ► Comparisons with the previous correlation demonstrate the need for an update

  15. Economic performance optimization of an absorption cooling system under uncertainty

    Many of the strategies devised so far to address the optimization of energy systems are deterministic approaches that rely on estimated data. However, in real world applications there are many sources of uncertainty that introduce variability into the decision-making problem. Within this general context, we propose a novel approach to address the design of absorption cooling systems under uncertainty in the energy cost. As opposed to other approaches that optimize the expected performance of the system as a single objective, in our method the design task is formulated as a stochastic bi-criteria non-linear optimization problem that simultaneously accounts for the minimization of the expected total cost and the financial risk associated with the investment. The latter criterion is measured by the downside risk, which avoids the need to define binary variables thus improving the computational performance of the model. The capabilities of the proposed modeling framework and solution strategy are illustrated in a case study problem that addresses the design of a typical absorption cooling system. Numerical results demonstrate that the method presented allows to manage the risk level effectively by varying the area of the heat exchangers of the absorption cycle. Specifically, our strategy allows identifying the optimal values of the operating and design variables of the cycle that make it less sensitive to fluctuations in the energy price, thus improving its robustness in the face of uncertainty.

  16. The Origin of Intermediate-Redshift Lyman Alpha Absorption Systems

    Lanzetta, K. M.; Bowen, D. V.; Tytler, D.; Webb, J. K.; Sealey, K. M.

    1994-01-01

    We present initial results of an imaging and spectroscopic survey of faint galaxies in fields of Hubble Space Telescope spectroscopic target QSOs. The primary objectives of the survey are (a) to determine the incidence, extent, and covering factor of extended gaseous envelopes of luminous galaxies and (b) to determine the fraction of Lyman alpha absorption systems that arise in luminous galaxies. The goal of the survey is to identify in each field under consideration all objects with apparent...

  17. The parsec-scale structure of radio-loud broad absorption line quasars

    Bruni, G.; Dallacasa, D.; Mack, K.-H.; Montenegro-Montes, F. M.; González-Serrano, J. I.; Holt, J.; Jiménez-Luján, F.

    2013-06-01

    Context. Broad absorption line quasars (BAL QSOs) belong to a class of objects not well-understood as yet. Their UV spectra show BALs in the blue wings of the UV resonance lines, owing to ionized gas with outflow velocities up to 0.2 c. They can have radio emission that is difficult to characterize and that needs to be studied at various wavelengths and resolutions. Aims: We aim to study the pc-scale properties of their synchrotron emission and, in particular, to determine their core properties. Methods: We performed observations in the Very Long Baseline Interferometry (VLBI) technique, using both the European VLBI Network (EVN) at 5 GHz, and the Very Long Baseline Array (VLBA) at 5 and 8.4 GHz to map the pc-scale structure of the brightest radio-loud objects of our sample, allowing a proper morphological interpretation. Results: A variety of morphologies have been found: 9 BAL QSOs on a total of 11 observed sources have a resolved structure. Core-jet, double, and symmetric objects are present, suggesting different orientations. In some cases the sources can be young GPS or CSS. The projected linear size of the sources, also considering observations from our previous work for the same objects, can vary from tens of pc to hundreds of kpc. In some cases, a diffuse emission can be supposed from the missing flux-density with respect to previous lower resolution observations. Finally, the magnetic field strength does not significantly differ from the values found in the literature for radio sources with similar sizes. Conclusions: These results are not easily interpreted with the youth scenario for BAL QSOs, in which they are generally compact objects still expelling a dust cocoon. The variety of orientations, morphologies, and extensions found are presumably related to different possible angles for the BAL producing outflows, with respect to the jet axis. Moreover, the phenomenon could be present in various phases of the QSO evolution. Table 3 is available in

  18. THE LONG-TERM X-RAY VARIABILITY OF BROAD ABSORPTION LINE QUASARS

    We analyze the long-term (rest-frame 3-30 yr) X-ray variability of 11 broad absorption line (BAL) quasars, mainly to constrain the variation properties of the X-ray absorbing shielding gas that is thought to play a critical role in BAL wind launching. Our BAL quasar sample has coverage with multiple X-ray observatories including Chandra, XMM-Newton, BeppoSAX, ASCA, ROSAT, and Einstein; 3-11 observations are available for each source. For seven of the eleven sources we have obtained and analyzed new Chandra observations suitable for searching for any strong X-ray variability. We find highly significant X-ray variability in three sources (PG 1001+054, PG 1004+130, and PG 2112+059). The maximum observed amplitude of the 2-8 keV variability is a factor of 3.8 ± 1.3, 1.5 ± 0.2, and 9.9 ± 2.3 for PG 1001+054, PG 1004+130, and PG 2112+059, respectively, and these sources show detectable variability on rest-frame timescales down to 5.8, 1.4, and 0.5 yr. For PG 1004+130 and PG 2112+059 we also find significant X-ray spectral variability associated with the flux variability. Considering our sample as a whole, we do not find that BAL quasars exhibit exceptional long-term X-ray variability when compared to the quasar population in general. We do not find evidence for common strong changes in the shielding gas owing to physical rearrangement or accretion-disk rotation, although some changes are found; this has implications for modeling observed ultraviolet BAL variability. Finally, we report for the first time an X-ray detection of the highly polarized and well-studied BAL quasar IRAS 14026+4341 in its new Chandra observation.

  19. A strong redshift dependence of the broad absorption line quasar fraction

    Allen, James T.; Hewett, Paul C.; Maddox, Natasha; Richards, Gordon T.; Belokurov, Vasily

    2011-01-01

    We describe the application of non-negative matrix factorization to generate compact reconstructions of quasar spectra from the Sloan Digital Sky Survey (SDSS), with particular reference to broad absorption line quasars (BALQSOs). BAL properties are measured for Si IVλ1400, C IVλ1550, Al IIIλ1860 and Mg IIλ2800, resulting in a catalogue of 3547 BALQSOs. Two corrections, based on extensive testing of synthetic BALQSO spectra, are applied in order to estimate the intrinsic fraction of C IV BALQSOs. First, the probability of an observed BALQSO spectrum being identified as such by our algorithm is calculated as a function of redshift, signal-to-noise ratio and BAL properties. Secondly, the different completenesses of the SDSS target selection algorithm for BALQSOs and non-BAL quasars are quantified. Combining the detection probabilities with an intrinsic E(B-V) distribution capable of reproducing the observed increase in mean E(B-V) with increasing redshift, the intrinsic C IV BALQSO fraction is 41 ± 5 per cent. Our analysis of the selection effects allows us to measure the dependence of the intrinsic C IV BALQSO fraction on luminosity and redshift. We find a factor of 3.5 ± 0.4 decrease in the intrinsic fraction from the highest redshifts, z≃ 4.0, down to z≃ 2.0. The redshift dependence implies that an orientation effect alone is not sufficient to explain the presence of BAL troughs in some but not all quasar spectra. Our results are consistent with the intrinsic BALQSO fraction having no strong luminosity dependence, although with 3σ limits on the rate of change of the intrinsic fraction with luminosity of -6.9 and 7.0 per cent dex-1 we are unable to rule out such a dependence.

  20. The Sizes and Kinematic Structure of Absorption Systems Towards the Lensed Quasar APM08279+5255

    Ellison, S L; Pettini, M; Lewis, G F; Aracil, B; Petitjean, P; Srianand, R; Ellison, Sara L.; Ibata, Rodrigo; Pettini, Max; Lewis, Geraint F.; Aracil, Bastien; Petitjean, Patrick

    2003-01-01

    We have obtained spatially resolved spectra of the z=3.911 triply imaged QSO APM08279+5255 using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). We study the line of sight equivalent width (EW) differences and velocity shear of high and low ionization absorbers (including a damped Lyman alpha [DLA] system identified in a spatially unresolved ground based spectrum) in the three lines of sight. We find that high ionization systems (primarily CIV absorbers) do not exhibit strong EW variations on scales 80%) over kpc scales. A minimum radius for strong (EW > 0.3 A) MgII systems of > 1.4 kpc is inferred from absorption coincidences in all lines of sight. For weak MgII absorbers (EW < 0.3 A), a maximum likelihood analysis indicates a most probable coherence scale of 2.0 kpc for a uniform spherical geometry, with 95% confidence limits ranging between 1.5 and 4.4 kpc. Finally, for systems with weak absorption that can be confidently converted to column densities, we find...

  1. On-line preconcentration and determination of mercury in biological and environmental samples by cold vapor-atomic absorption spectrometry

    An on-line procedure for the determination of traces of total mercury in environmental and biological samples is described. The present methodology combines cold vapor generation associated to atomic absorption spectrometry (CV-AAS) with preconcentration of the analyte on a minicolumn packed with activated carbon. The retained analyte was quantitatively eluted from the minicolumn with nitric acid. After that, volatile specie of mercury was generated by merging the acidified sample and sodium tetrahydroborate(III) in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the atomizer device. Optimizations of both, preconcentration and mercury volatile specie generation variables were carried out using two level full factorial design (23) with 3 replicates of the central point. Considering a sample consumption of 25 mL, an enrichment factor of 13-fold was obtained. The detection limit (3σ) was 10 ng L-1 and the precision (relative standard deviation) was 3.1% (n = 10) at the 5 μg L-1 level. The calibration curve using the preconcentration system for mercury was linear with a correlation coefficient of 0.9995 at levels near the detection limit up to at least 1000 μg L-1. Satisfactory results were obtained for the analysis of mercury in tap water and hair samples

  2. Absorption-amplification response with or without spontaneously generated coherence effect in a four-level atomic system

    李家华; 杨文星; 彭菊村

    2004-01-01

    We discuss and analyze the absorption properties of a weak probe field in a typical four-level atomic system in the presence of a spontaneously generated coherence (SGC) term. The influences of the SGC and a coherent pump field on the probe absorption-amplification are investigated. The results show that the absorption of such a weak probe field can be dramatically enhanced due to the SGC effect. At the same time, the probe-absorption profile exhibits a two-peak structure and the probe-absorption peak gradually decreases as the pump intensity increases. On the contrary, the amplification of such a weak probe field near the line center of the probe transition can be achieved by adjusting the coherent pump field intensity in the absence of the SGC effect.

  3. Optimization of A 2-Micron Laser Frequency Stabilization System for a Double-Pulse CO2 Differential Absorption Lidar

    Chen, Songsheng; Yu, Jirong; Bai, Yingsin; Koch, Grady; Petros, Mulugeta; Trieu, Bo; Petzar, Paul; Singh, Upendra N.; Kavaya, Michael J.; Beyon, Jeffrey

    2010-01-01

    A carbon dioxide (CO2) Differential Absorption Lidar (DIAL) for accurate CO2 concentration measurement requires a frequency locking system to achieve high frequency locking precision and stability. We describe the frequency locking system utilizing Frequency Modulation (FM), Phase Sensitive Detection (PSD), and Proportional Integration Derivative (PID) feedback servo loop, and report the optimization of the sensitivity of the system for the feed back loop based on the characteristics of a variable path-length CO2 gas cell. The CO2 gas cell is characterized with HITRAN database (2004). The method can be applied for any other frequency locking systems referring to gas absorption line.

  4. The elettra beam line control system

    Elettra is a third generation Synchrotron Light Source located in Trieste (Italy). It consists of a full energy linac injector and a storage ring with beam energies between 1.5 and 2 GeV. The facility is scheduled to be operational by end 1993. For the whole project 22 beam lines from insertion devices are foreseen, each of them is composed of a large number of measurement and controls instruments, most of them embedded in intelligent devices; in addition each beam line can be considered unique compared to the others, having been designed to provide a different kind of synchrotron radiation. This results in a large not homogenous environment where more than 200,000 physical points have to be controlled. A joint team composed of Softeco Sismat and Digital Equipment has developed a fully automated beam line control system able to give full remote controls, with different kind of access rights, to beam line users and beam line specialists as well as a full integration with experiment control systems. ((orig.))

  5. XMM-Newton Survey of Local O VII Absorption Lines in the Spectra of Active Galactic Nuclei

    Fang, Taotao; Bullock, James S; Ma, Renyi

    2015-01-01

    Highly ionized, z=0 metal absorption lines detected in the X-ray spectra of background active galactic nuclei (AGNs) provide an effective method to probe the hot ($T\\sim10^6$ K) gas and its metal content in and around the Milky Way. We present an all-sky survey of the $K_{\\alpha}$ transition of the local O VII absorption lines obtained by Voigt-profile fitting archival XMM-Newton observations. A total of 43 AGNs were selected, among which 12 are BL Lac-type AGNs, and the rest are Seyfert 1 galaxies. At above the $3\\sigma$ level the local O VII absorption lines were detected in 21 AGNs, among which 7 were newly discovered in this work. The sky covering fraction, defined as the ratio between the number of detections and the sample size, increases from at about 40% for all targets to 100% for the brightest targets, suggesting a uniform distribution of the O VII absorbers. We correlate the line equivalent width with the Galactic coordinates and do not find any strong correlations between these quantities. Some AG...

  6. On-line Bayesian System Identification

    Romeres, Diego; Prando, Giulia; Pillonetto, Gianluigi; Chiuso, Alessandro

    2016-01-01

    We consider an on-line system identification setting, in which new data become available at given time steps. In order to meet real-time estimation requirements, we propose a tailored Bayesian system identification procedure, in which the hyper-parameters are still updated through Marginal Likelihood maximization, but after only one iteration of a suitable iterative optimization algorithm. Both gradient methods and the EM algorithm are considered for the Marginal Likelihood optimization. We c...

  7. A upper limit for water dimer absorption in the 750 nm spectral region and a revised water line list

    A. J. L. Shillings

    2010-10-01

    Full Text Available The absorption of solar radiation by water dimer molecules in the Earth's atmosphere can potentially act as a positive feedback effect for climate change. There seems little doubt from the results of previous laboratory and theoretical studies that significant concentrations of the water dimer should be present in the atmosphere, yet attempts to detect water dimer absorption signatures in atmospheric field studies have so far yielded inconclusive results. Here we report spectral measurements in the near-infrared in the expected region of the third overtone of the water dimer hydrogen-bonded OHb stretching vibration around 750 nm. The results were obtained using broadband cavity ringdown spectroscopy (BBCRDS, a methodology that allows absorption measurements to be made under controlled laboratory conditions but over absorption path lengths representative of atmospheric conditions. In order to account correctly and completely for overlapping absorption of monomer molecules in the same spectral region, we have also constructed a new list of spectral data (UCL08 for the water monomer in the 750–20 000 cm−1 (13 μm–500 nm range.

    Our results show that the additional lines included in the UCL08 spectral database provide a substantially improved representation of the measured water monomer absorption in the 750 nm region, particularly at wavelengths dominated by weak monomer absorption features. No absorption features which could not be attributed to the water monomer were detected in the BBCRDS experiments up to water mixing ratios more than an order of magnitude greater than those in the ambient atmosphere. The absence of detectable water dimer features leads us to conclude that, in the absence of significant errors in calculated dimer oscillator strengths or monomer/dimer equilibrium constants, the widths of water dimer features present around 750 nm must be substantially greater (~100 cm−1 HWHM than

  8. Total on-line purchasing system (TOPS)

    Collins, N.

    1995-11-01

    The Information Management Division (IMD) at LLNL is developing a new purchasing system for the Procurement Department. The first major development of this new system is called, {open_quotes}Total On-Line Purchasing System{close_quotes} (TOPS). TOPS will help speed up the requisitioning process by having requisitions electronically entered by requesters and electronically sent to buyers to be put on Purchase Orders. The new purchasing system will use Electronic Commerce (EC)/Electronic Data Interchange (EDI), to help increase transaction flows for shipping notices, RFQs, Quotes, Purchase Orders, and Invoices. ANSI X.12 is the EDI standard that this new EC will use.

  9. Off-line programming (OLP) system comparison

    Off-line programming (OLP) systems are being used to conceptualize, design, simulate, and now control automated robotic workcells. Currently available systems by Deneb, SILMA, and Cimetrix are being used at the Lawrenece Livermore National Laboratory (LLNL) to simulate and control automated robotic systems for radioactive material processing and hazardous waste sorting. The differences in system architectures, workcell and robot calibration procedures, operator interface, and graphical output capability of each will be discussed. The relative strengths and weaknesses of these attributes will be discussed as they relate to varying applications in robotic workcell development and control

  10. Monitoring and analysis of an absorption air-conditioning system

    Perez de Vinaspre, M.; Bourouis, M.; Coronas, A. [Centro de Innovacion Tecnologica en Revalorizacion Energetica y Refrigeracion, Tarragona (Spain); Garcia, A.; Soto, V.; Pinazo, J.M. [E.T.S. Ingenieros Industriales, Valencia (Spain)

    2004-09-01

    In the last few years, high-energy consumption due to air-conditioning has led to a growing interest in the efficient use of energy in buildings. Although simulation programs have always been the main tools for analyzing energy in buildings, the reliability of their results is often compromised by a lack of certainty to reflect real conditions. The aim of this work is to monitorize and analyze the thermal behavior of an absorption-based air-conditioning installation of a university building in Tarragona, Spain. The existing monitoring system of the installation has been improved by implementing additional sensors and flow meters. The data has been stored during summer 2002 and used to assess the energy balance of the air-conditioning installation and the operational regime of the absorption chiller. [Author].

  11. Invisible Active Galactic Nuclei. II. Radio Morphologies and Five New H i 21cm Absorption Line Detectors

    Yan, Ting; Stocke, John T.; Darling, Jeremy; Momjian, Emmanuel; Sharma, Soniya; Kanekar, Nissim

    2016-03-01

    This is the second paper directed toward finding new highly redshifted atomic and molecular absorption lines at radio frequencies. To this end, we selected a sample of 80 candidates for obscured radio-loud active galactic nuclei (AGNs) and presented their basic optical/near-infrared (NIR) properties in Paper I. In this paper, we present both high-resolution radio continuum images for all of these sources and H i 21 cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz Very Large Array continuum observations find that 52 sources are compact or have substantial compact components with size 0.1 Jy at 4.9 GHz. The 36 most compact sources were then observed with the Very Long Baseline Array at 1.4 GHz. One definite and 10 candidate Compact Symmetric Objects (CSOs) are newly identified, which is a detection rate of CSOs ∼three times higher than the detection rate previously found in purely flux-limited samples. Based on possessing compact components with high flux densities, 60 of these sources are good candidates for absorption-line searches. Twenty-seven sources were observed for H i 21 cm absorption at their photometric or spectroscopic redshifts with only six detections (five definite and one tentative). However, five of these were from a small subset of six CSOs with pure galaxy optical/NIR spectra (i.e., any AGN emission is obscured) and for which accurate spectroscopic redshifts place the redshifted 21 cm line in a radio frequency intereference (RFI)-free spectral “window” (i.e., the percentage of H i 21 cm absorption-line detections could be as high as ∼90% in this sample). It is likely that the presence of ubiquitous RFI and the absence of accurate spectroscopic redshifts preclude H i detections in similar sources (only 1 detection out of the remaining 22 sources observed, 13 of which have only photometric redshifts); that is, H i absorption may well be present but is masked by the RFI. Future searches for

  12. System Analysis on Absorption Chiller Utilizing Intermediate Wasted Heat

    Yamada, Miki; Suzuki, Hiroshi; Usui, Hiromoto

    A system analysis has been performed for the multi-effect absorption chiller (MEAC) applied as a bottoming system of 30kW class hybrid system including micro gas turbine (MGT) and solid oxide fuel cell (SOFC) hybrid system. In this paper, an intermediate wasted heat utilization (IWHU) system is suggested for lifting up the energy efficiency of the whole system and coefficient of performance (COP) of MEAC. From the results, the suggested IWHU system was found to show the very high energy efficiency compared with a terminal wasted heat utilization (TWHU) system that uses only the heat exhausted from the terminal of MGT/SOFC system. When TWHU system is applied for MEAC, the utilized heat from the MGT/SOFC system is found to remain low because the temperature difference between the high temperature generator and the wasted heat becomes small. Then, the energy efficiency does not become high in spite of high COP of MEAC. On the other hand, the IWHU system could increase the utilized heat for MEAC as performs effectively. The exergy efficiency of IWHU system is also revealed to be higher than that of a direct gas burning system of MEAC, because the wasted heat is effectively utilized in the IWHU system.

  13. COMPARISON OF ENERGY AND EXERGY EFFICIENCIES OF ABSORPTION REFRIGERATION SYSTEM WITH MECHANICAL COMPRESSION REFRIGERATION SYSTEM

    YAKAR, Gülay; KARABACAK, Rasim; Burçin DEDA ALTAN

    2005-01-01

    In this study, energy and exergy analysis of absorption refrigeration system using LiBr- water and mechanical compression refrigeration system using R134-a were performed at different evaporation temperatures. The results are presented in tables and figures.

  14. Searching for narrow absorption and emission lines in XMM-Newton spectra of gamma-ray bursts

    Campana, S; D'Avanzo, P; Ghirlanda, G; Melandri, A; Pescalli, A; Salafia, O S; Salvaterra, R; Tagliaferri, G; Vergani, S D

    2016-01-01

    We present the results of a spectroscopic search for narrow emission and absorption features in the X-ray spectra of long gamma-ray burst (GRB) afterglows. Using XMM-Newton data, both EPIC and RGS spectra, of six bright (fluence >10^{-7} erg cm^{-2}) and relatively nearby (z=0.54-1.41) GRBs, we performed a blind search for emission or absorption lines that could be related to a high cloud density or metal-rich gas in the environ close to the GRBs. We detected five emission features in four of the six GRBs with an overall statistical significance, assessed through Monte Carlo simulations, of <3.0 sigma. Most of the lines are detected around the observed energy of the oxygen edge at ~0.5 keV, suggesting that they are not related to the GRB environment but are most likely of Galactic origin. No significant absorption features were detected. A spectral fitting with a free Galactic column density (N_H) testing different models for the Galactic absorption confirms this origin because we found an indication of an...

  15. Reconstruction of combustion temperature and gas concentration distributions using line-of-sight tunable diode laser absorption spectroscopy

    Zhang, Zhirong; Sun, Pengshuai; Pang, Tao; Xia, Hua; Cui, Xiaojuan; Li, Zhe; Han, Luo; Wu, Bian; Wang, Yu; Sigrist, Markus W.; Dong, Fengzhong

    2016-07-01

    Spatial temperature and gas concentration distributions are crucial for combustion studies to characterize the combustion position and to evaluate the combustion regime and the released heat quantity. Optical computer tomography (CT) enables the reconstruction of temperature and gas concentration fields in a flame on the basis of line-of-sight tunable diode laser absorption spectroscopy (LOS-TDLAS). A pair of H2O absorption lines at wavelengths 1395.51 and 1395.69 nm is selected. Temperature and H2O concentration distributions for a flat flame furnace are calculated by superimposing two absorption peaks with a discrete algebraic iterative algorithm and a mathematical fitting algorithm. By comparison, direct absorption spectroscopy measurements agree well with the thermocouple measurements and yield a good correlation. The CT reconstruction data of different air-to-fuel ratio combustion conditions (incomplete combustion and full combustion) and three different types of burners (one, two, and three flat flame furnaces) demonstrate that TDLAS has the potential of short response time and enables real-time temperature and gas concentration distribution measurements for combustion diagnosis.

  16. Energy and exergy analyses of the diffusion absorption refrigeration system

    This paper describes the thermodynamic analyses of a DAR (diffusion absorption refrigeration) cycle. The experimental apparatus is set up to an ammonia–water DAR cycle with helium as the auxiliary inert gas. A thermodynamic model including mass, energy and exergy balance equations are presented for each component of the DAR cycle and this model is then validated by comparison with experimental data. In the thermodynamic analyses, energy and exergy losses for each component of the system are quantified and illustrated. The systems' energy and exergy losses and efficiencies are investigated. The highest energy and exergy losses occur in the solution heat exchanger. The highest energy losses in the experimental and theoretical analyses are found 25.7090 W and 25.4788 W respectively, whereas those losses as to exergy are calculated 13.7933 W and 13.9976 W. Although the values of energy efficiencies obtained from both the model and experimental studies are calculated as 0.1858, those values, in terms of exergy efficiencies are found 0.0260 and 0.0356. - Highlights: • The diffusion absorption refrigerator system is designed manufactured and tested. • The energy and exergy analyses of the system are presented theoretically and experimentally. • The energy and exergy losses are investigated for each component of the system. • The highest energy and exergy losses occur in the solution heat exchanger. • The energy and the exergy performances are also calculated

  17. Absorption-line ''forest'' in quasar spectra, and the structure of the universe

    Doroshkevich, A.G.; Muket, J.P.

    1985-05-01

    The ''forest'' of absorption lines observed in the spectrum of distant quasars is interpreted in light of the adiabatic (pancake) theory for the origin and evolution of structure in the universe. The hidden mass might reside in neutrino-like particles (perhaps unstable) having a rest mass of about 60--100 eV. Opportunities for testing the hypothesis observationally are discussed.

  18. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    Shi, Xiheng; Zhou, Hongyan; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-03-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of Hβ shows a variation of more than 5σ at a high velocity portion (\\gt 3000 {km} {{{s}}}-1) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He i and optical Fe ii absorptions (λ4233 from b4P5/2 level and λ5169 from a6S5/2) at the same velocity. These Fe ii lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of n({{H}})≈ {10}9.1 {{cm}}-3 and a column density of {N}{col}({{H}})≈ {10}23 {{cm}}-2 for the BOSS data, but the model fails to predict the variations of ionic column densities between the SDSS and BOSS observations if changes in ionizing flux are assumed. We thus propose transverse motion of the absorbing gas being the cause of the observed broad Balmer absorption line variability. In fact, we find that the changes in covering factors of the absorber can well-reproduce all of the observed variations. The absorber is estimated ∼0.94 pc away from the central engine, which is where the outflow likely experiences deceleration due to the collision with the surrounding medium. This scheme is consistent with the argument that LoBAL QSOs may represent the transition from obscured star-forming galaxies to classic QSOs.

  19. Absorption lines from magnetically driven winds in X-ray binaries

    Chakravorty, S.; Petrucci, P.-O.; Ferreira, J.; Henri, G.; Belmont, R.; Clavel, M.; Corbel, S.; Rodriguez, J.; Coriat, M.; Drappeau, S.; Malzac, J.

    2016-05-01

    Context. High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines suggesting the presence of outflowing winds. Furthermore, observations show that the disk winds are equatorial and they occur in the Softer (disk dominated) states of the outburst and are less prominent or absent in the Harder (power-law dominated) states. Aims: We want to test whether the self-similar magneto-hydrodynamic (MHD) accretion-ejection models can explain the observational results for accretion disk winds in BHBs. In our models, the density at the base of the outflow from the accretion disk is not a free parameter. This mass loading is determined by solving the full set of dynamical MHD equations without neglecting any physical term. Thus, the physical properties of the outflow depend on and are controlled by the global structure of the disk. Methods: We studied different MHD solutions characterized by different values of the disk aspect ratio (ɛ) and the ejection efficiency (p). We also generate two kinds of MHD solutions depending on the absence (cold solution) or presence (warm solution) of heating at the disk surface. Such heating could be either from dissipation of energy due to MHD turbulence in the disk or from illumination of the disk surface. Warm solutions can have large (>0.1) values of p, which would imply larger wind mass loading at the base of the outflow. We use each of these MHD solutions to predict the physical parameters (distance, density, velocity, magnetic field, etc.) of an outflow. Motivated by observational results, we have put limits on the ionization parameter (ξ), column density, and timescales. Further constraints were derived for the allowed values of ξ from thermodynamic instability considerations, particularly for the Hard SED. These physical constraints were imposed on each of these outflows to select regions within it, which are consistent with the observed winds. Results: The cold MHD solutions are found to be

  20. Absorption Enhancing Excipients in Systemic Nasal Drug Delivery

    Edward T. Maggio

    2014-06-01

    Full Text Available Intranasal drug delivery is becoming an increasingly important form of drug administration for chronic and chronic-intermittent diseases. Important new applications in development include drugs for diabetes, osteoporosis, obesity, certain types of convulsive disorders, migraine headaches, symptomatic pain relief, nausea, and anxiety, among others. Transmucosal absorption across the nasal mucosa is generally limited to molecules under 1,000 Da in size. Systemic delivery of molecules larger than this requires formulation with a suitable transmucosal absorption enhancer. More than one hundred potential transmucosal absorption enhancing excipients have been tested to date. Nearly all have failed to be practical due to poor effectiveness or unacceptable toxicity to mucosal tissue. Alkylsaccharides, cyclodextrins, and chitosan's have emerged as the leading candidates for potential broad clinical applications and are allowing development of convenient, patient-friendly, needle free formulations of small molecule drugs, as well as peptide and protein drugs that can be administered at home, at work, or in other public and private settings outside of the doctor’s office or hospital environment.

  1. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    Shi, Xiheng; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-01-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of H$\\beta$ shows a variation of more than 5$\\sigma$ at a high velocity portion ($>3000\\ \\mathrm{km\\ s}^{-1}$) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He I and optical Fe II absorptions ($\\lambda 4233$ from b$^4$P$_{5/2}$ level and $\\lambda 5169$ from a$^6$S$_{5/2}$) at the same velocity. These Fe II lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of $n(\\mathrm{H})\\approx 10^{9.1}\\ \\mathrm{cm}^{-3}$ and a column density of $N_{\\mathrm{col}}(\\mathrm{H})\\approx 10^{23}\\ \\mathrm{cm}^{-2}$ for ...

  2. Fence line noble gas monitoring system

    A new system has been developed for monitoring noble gas emissions at the fence line around the Pickering NPP in Canada. The system differs from the traditional method of assessing the dose to the critical group based on meteorological models. Instead, the new system monitors the dose directly at the fence line, which in fact has reduced the reported doses by 1 to 2 orders of magnitude. Typical annual Minimum Detectable Levels (MDLs)4 in Air Kerma are 1.8 nGy (135Xe), 4.2 nGy (135Xe), and 11.0 nGy (41Ar). The complete system comprises 7 self-contained Na(Tl) detector units located around the Pickering fence line. System design makes each detector assembly a stand-alone unit with internal data scanning, Stabilization and data storage capability. Each detector has been calibrated for Air Kerma, Ambient Dose Equivalent, Effective Dose (adults), and Effective Dose (Juvenile)5. The detector systems are polled every 24 hrs. (user selected from real-time to every 7 days as required) by one or more central computers. The central computers collect spectral data from each detector unit and store all the data in a SQL database. The data is analyzed and preliminary noble gas concentration calculated. Every month the complete data set for the month is reevaluated based on actual wind information using the new computed calibration factors, to achieve maximum data accuracy. The system creates automatic monthly reports with tables of emissions and MDLs. Included in the reports are also graphs of the emissions during the month. (author)

  3. Near-UV Absorption, Chromospheric Activity, and Star-Planet Interactions in the WASP-12 system

    Haswell, C A; Ayres, T; France, K; Froning, C S; Holmes, S; Kolb, U C; Busuttil, R; Street, R A; Hebb, L; Cameron, A Collier; Enoch, B; Burwitz, V; Rodriguez, J; West, R G; Pollacco, D; Wheatley, P J; Carter, A; 10.1088/0004-637X/760/1/79

    2013-01-01

    We observed the extreme close-in hot Jupiter system, WASP-12, with HST. Near-UV transits up to three times deeper than the optical transit of WASP-12b reveal extensive diffuse gas, extending well beyond the Roche lobe. The distribution of absorbing gas varies between visits. The deepest NUV transits are at wavelength ranges with strong photospheric absorption, implying the absorbing gas may have temperature and composition similar to the stellar photosphere. Our spectra reveal significantly enhanced absorption (greater than 3 \\sigma below the median) at ~200 wavelengths on each of two HST visits; 65 of these wavelengths are consistent between the two visits, using a strict criterion for velocity matching which excludes matches with velocity shifts exceeding ~20 km/s. Excess transit depths are robustly detected throughout the inner wings of the MgII resonance lines independently on both HST visits. We detected absorption in FeII 2586A, the heaviest species yet detected in an exoplanet transit. The MgII line co...

  4. X-RAY ABSORPTION ON URANIUM SYSTEMS AT VARIOUS THRESHOLDS

    Kalkowski, G.; Kaindl, G.; Brewer, W.; Krone, W

    1986-01-01

    We have studied the near edge X-ray absorption fine structure of various metallic and non-metallic U compounds at the L3, M3, M4,5, N4,5, and O4,5 thresholds using transmission and total-electron-yield techniques. At the L3 thresholds, a chemical shift of ≈4 eV between trivalent and tetravalent U compounds is observed, which drops to ≈2eV between the latter and hexavalent U systems. This indicates extended 5f character and a 5f count close to two in the high oxidation states. The M4,5 thresho...

  5. The dependence of C IV broad absorption line properties on accompanying Si IV and Al III absorption: relating quasar-wind ionization levels, kinematics, and column densities

    Filiz Ak, N.; Brandt, W. N.; Schneider, D. P.; Trump, J. R. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3 (Canada); Anderson, S. F. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Hamann, F. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Pâris, I. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Petitjean, P. [Institut d' Astrophysique de Paris, Universite Paris 6, F-75014 Paris (France); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Shen, Yue [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); York, Don, E-mail: nfilizak@astro.psu.edu [Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 (United States)

    2014-08-20

    We consider how the profile and multi-year variability properties of a large sample of C IV Broad Absorption Line (BAL) troughs change when BALs from Si IV and/or Al III are present at corresponding velocities, indicating that the line of sight intercepts at least some lower ionization gas. We derive a number of observational results for C IV BALs separated according to the presence or absence of accompanying lower ionization transitions, including measurements of composite profile shapes, equivalent width (EW), characteristic velocities, composite variation profiles, and EW variability. We also measure the correlations between EW and fractional-EW variability for C IV, Si IV, and Al III. Our measurements reveal the basic correlated changes between ionization level, kinematics, and column density expected in accretion-disk wind models; e.g., lines of sight including lower ionization material generally show deeper and broader C IV troughs that have smaller minimum velocities and that are less variable. Many C IV BALs with no accompanying Si IV or Al III BALs may have only mild or no saturation.

  6. First Detection of HCO$^+$ Absorption in the Magellanic System

    Murray, Claire E; McClure-Griffiths, N M; Putman, M E; Liszt, H S; Wong, Tony; Richter, P; Dawson, J R; Dickey, John M; Lindner, Robert R; Babler, Brian L; Allison, J R

    2015-01-01

    We present the first detection of HCO$^+$ absorption in the Magellanic System. Using the Australia Telescope Compact Array (ATCA), we observed 9 extragalactic radio continuum sources behind the Magellanic System and detected HCO$^+$ absorption towards one source located behind the leading edge of the Magellanic Bridge. The detection is located at LSR velocity of $v=214.0 \\pm 0.4\\rm\\,km\\,s^{-1}$, with a full width at half maximum of $\\Delta v=4.5\\pm 1.0\\rm\\,km\\,s^{-1}$ and optical depth of $\\tau(\\rm HCO^+)=0.10\\pm 0.02$. Although there is abundant neutral hydrogen (HI) surrounding the sightline in position-velocity space, at the exact location of the absorber the HI column density is low, $<10^{20}\\rm\\,cm^{-2}$, and there is little evidence for dust or CO emission from Planck observations. While the origin and survival of molecules in such a diffuse environment remains unclear, dynamical events such as HI flows and cloud collisions in this interacting system likely play an important role.

  7. Performance analysis of solar powered absorption refrigeration system

    Abu-Ein, Suleiman Qaseem; Fayyad, Sayel M.; Momani, Waleed; Al-Bousoul, Mamdouh

    2009-12-01

    The present work provides a detailed thermodynamic analysis of a 10 kW solar absorption refrigeration system using ammonia-water mixtures as a working medium. This analysis includes both first law and second law of thermodynamics. The coefficient of performance (COP), exergetic coefficient of performance (ECOP) and the exergy losses (Δ E) through each component of the system at different operating conditions are obtained. The minimum and maximum values of COP and ECOP were found to be at 110 and 200°C generator temperatures respectively. About 40% of the system exergy losses were found to be in the generator. The maximum exergy losses in the absorber occur at generator temperature of 130°C for all evaporator temperatures. A computer simulation model is developed to carry out the calculations and to obtain the results of the present study.

  8. NEAR-ULTRAVIOLET ABSORPTION, CHROMOSPHERIC ACTIVITY, AND STAR-PLANET INTERACTIONS IN THE WASP-12 SYSTEM

    Haswell, C. A.; Fossati, L.; Holmes, S.; Kolb, U. C.; Busuttil, R.; Carter, A. [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ayres, T.; France, K.; Froning, C. S. [Center for Astrophysics and Space Astronomy, University of Colorado, 593 UCB, Boulder, CO 80309-0593 (United States); Street, R. A. [Las Cumbres Observatory Global Telescope Network, Inc., 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Hebb, L. [Department of Physics and Astronomy, Vanderbilt University, 6301 Stevenson Center Nashville, TN 37235 (United States); Cameron, A. Collier; Enoch, B. [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Burwitz, V. [Max Planck Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Rodriguez, J. [Observatori Astronomic de Mallorca, Cami de l' Observatori, E-07144 Costitx, Mallorca (Spain); West, R. G. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Pollacco, D.; Wheatley, P. J., E-mail: C.A.Haswell@open.ac.uk, E-mail: l.fossati@open.ac.uk, E-mail: cynthia.froning@colorado.edu, E-mail: leslie.hebb@vanderbilt.edu [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2012-11-20

    Extended gas clouds have been previously detected surrounding the brightest known close-in transiting hot Jupiter exoplanets, HD 209458 b and HD 189733 b; we observed the distant but more extreme close-in hot Jupiter system, WASP-12, with Hubble Space Telescope (HST). Near-UV (NUV) transits up to three times deeper than the optical transit of WASP-12 b reveal extensive diffuse gas, extending well beyond the Roche lobe. The distribution of absorbing gas varies between visits. The deepest NUV transits are at wavelength ranges with strong stellar photospheric absorption, implying that the absorbing gas may have temperature and composition similar to those of the stellar photosphere. Our spectra reveal significantly enhanced absorption (greater than 3{sigma} below the median) at {approx}200 individual wavelengths on each of two HST visits; 65 of these wavelengths are consistent between the two visits, using a strict criterion for velocity matching that excludes matches with velocity shifts exceeding {approx}20 km s{sup -1}. Excess transit depths are robustly detected throughout the inner wings of the Mg II resonance lines independently on both HST visits. We detected absorption in Fe II {lambda}2586, the heaviest species yet detected in an exoplanet transit. The Mg II line cores have zero flux, emission cores exhibited by every other observed star of similar age and spectral type are conspicuously absent. WASP-12 probably produces normal Mg II profiles, but the inner portions of these strong resonance lines are likely affected by extrinsic absorption. The required Mg{sup +} column is an order of magnitude greater than expected from the interstellar medium, though we cannot completely dismiss that possibility. A more plausible source of absorption is gas lost by WASP-12 b. We show that planetary mass loss can produce the required column. Our Visit 2 NUV light curves show evidence for a stellar flare. We show that some of the possible transit detections in resonance

  9. On the sizes of neutral hydrogen regions giving rise to damped Lyα absorption systems

    Monier, E. M.; Turnshek, D. A.; Rao, S.

    2009-08-01

    Using quasi-stellar object (QSO) absorption-line spectra obtained along closely spaced sightlines, we examine the transverse sizes of regions containing large columns of neutral hydrogen gas at redshifts z ~ 1.5. The observations are primarily of intervening damped Lyα (DLA) and sub-DLA absorption-line systems in gravitationally lensed QSOs. In particular, Hubble Space Telescope spectroscopy of the four-component Cloverleaf QSO (H1413+1143) reveals three new DLA/sub-DLA systems at z ~ 1.44, 1.49 and 1.66. A neutral hydrogen column density of NHI >= 2 × 1020atomscm-2 is required for a system to be classified as a DLA, but none of the three systems has an HI column density above the DLA threshold in all four components. Over component separations <1.4 arcsec in the Cloverleaf, corresponding to transverse sizes of ~5-12h-170kpc, the HI column densities typically change by factors of ~2-40. Similar observations of other QSOs containing absorption systems in the DLA regime are summarized from the literature. In addition to establishing approximate sizes for DLA regions, the results have implications for their volume-averaged HI gas number densities and neutral gas masses. By combining our results on DLA absorber sizes with published results on the sizes of lower column density QSO absorbers, which however arise in very ionized regions, we infer the useful relation that the typical transverse size of an absorber in the redshift interval z ~ [1, 2] is Sabs ~ 11h-170[NHI/1020]-1/4kpc. Based on observations made with the NASA/ESA Hubble Space Telescope. E-mail: emonier@brockport.edu

  10. Weak Hard X-ray Emission from Two Broad Absorption Line Quasars Observed with NuSTAR: Compton-thick Absorption or Intrinsic X-ray Weakness?

    Luo, B; Alexander, D M; Harrison, F A; Stern, D; Bauer, F E; Boggs, S E; Christensen, F E; Comastri, A; Craig, W W; Fabian, A C; Farrah, D; Fiore, F; Fuerst, F; Grefenstette, B W; Hailey, C J; Hickox, R; Madsen, K K; Matt, G; Ogle, P; Risaliti, G; Saez, C; Teng, S H; Walton, D J; Zhang, W W

    2013-01-01

    We present NuSTAR hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain ~400-600 hard X-ray (>10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (NH<1E24 cm^{-2}). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be NH~7E24 cm^{-2} if the weak hard X-ray emission is caused by obscuration from the shielding gas. We d...

  11. Industrial trigeneration using ammonia-water absorption refrigeration systems (AAR)

    In many industrial processes there is a simultaneous need for electric power and refrigeration at low temperatures. Examples are in the food and chemical industries. Nowadays the increase in fuel prices and the ecological implications are giving an impulse to energy technologies that better exploit the primary energy source and integrated production of utilities should be considered when designing a new production plant. The number of so-called trigeneration systems installations (electric generator and absorption refrigeration plant) is increasing. If low temperature refrigeration is needed (from 0 to -40 deg. C), ammonia-water absorption refrigeration plants can be coupled to internal combustion engines or turbogenerators. A thermodynamic system study of trigeneration configurations using a commercial software integrated with specifically designed modules is presented. The study analyzes and compares heat recovery from the primary mover at different temperature levels. In the last section a simplified economic assessment that takes into account disparate prices in European countries compares conventional electric energy supply from the grid and optimized trigeneration plants in one test case (10 MW electric power, 7000 h/year)

  12. Evolution of high-redshift Lyman-limit absorption systems

    Lanzetta, K.M. (Cambridge University Institute of Astronomy (England))

    1991-07-01

    Results are presented of a new spectroscopic survey of high-redshift Lyman-limit absorption systems. Based on this data set, the rate of incidence of the Lyman-limit systems with z greater than about 2.5 is found to evolve strongly with redshift in the sense that the product of the number density per unit comoving volume and the absorption cross section increases with increasing redshift. If the observed evolution indicates intrinsic evolution of the absorbers, this result suggests that the evolution detected previously for the C IV-selected absorbers over a similar redshift range is not naturally interpreted as evolution of the ionization level of the absorbers rather than as a chemical enrichment effect. The data are also used to investigate the H I column density distribution and to examine the multiple-component structure of the absorbing complexes. The H I column density distribution is found to be well fitted by a power-law form. 35 refs.

  13. The origin of intermediate-redshift Lyman alpha absorption systems

    Lanzetta, K M; Tytler, D; Webb, J K; Sealey, K M; Lanzetta, K M; Bowen, D V; Tytler, D; Webb, J K; Sealey, K M

    1994-01-01

    We present initial results of an imaging and spectroscopic survey of faint galaxies in fields of Hubble Space Telescope spectroscopic target QSOs. The primary objectives of the survey are (a) to determine the incidence, extent, and covering factor of extended gaseous envelopes of luminous galaxies and (b) to determine the fraction of Lyman alpha absorption systems that arise in luminous galaxies. The goal of the survey is to identify in each field under consideration all objects with apparent r-band magnitudes satisfying r< 21.5 within angular distances to the QSOs satisfying theta < 1.3 arcmin. We find that at z \\apl 1 most luminous galaxies are surrounded by extended gaseous envelopes of approx 160 h^{-1} kpc radius and roughly unit covering factor and that at z \\apl 1 the fraction of Ly alpha absorption systems that arise in luminous galaxies is at least 0.35 \\pm 0.10 and is likely 0.65 \\pm 0.18.

  14. New thermodynamical systems. Alternative of compression-absorption; Nouveaux systemes thermodynamiques. Alternative de la compression-absorption

    Feidt, M.; Brunin, O.; Lottin, O.; Vidal, J.F. [Universite Henri Poincare Nancy, 54 - Vandoeuvre-les-Nancy (France); Hivet, B. [Electricite de France, 77 - Moret sur Loing (France)

    1996-12-31

    This paper describes a 5 years joint research work carried out by Electricite de France (EdF) and the ESPE group of the LEMTA on compression-absorption heat pumps. It shows how a thermodynamical model of machinery, completed with precise exchanger-reactor models, allows to simulate and dimension (and eventually optimize) the system. A small power prototype has been tested and the first results are analyzed with the help of the models. A real scale experiment in industrial sites is expected in the future. (J.S.) 20 refs.

  15. The ALFALFA HI Absorption Pilot Survey: A Wide-Area Blind Damped Lyman Alpha System Survey of the Local Universe

    Darling, Jeremy; Haynes, Martha P; Giovanelli, Riccardo

    2011-01-01

    We present the results of a pilot survey for neutral hydrogen (HI) 21 cm absorption in the Arecibo Legacy Fast Arecibo L-Band Feed Array (ALFALFA) Survey. This project is a wide-area "blind" search for HI absorption in the local universe, spanning -650 km/s = 2x10^20 cm^-2) is Delta z = 7.0 (129 objects, assuming T_s = 100 K and covering fraction unity); for super-DLAs (N_HI >= 2x10^21 cm^-2) it is Delta z= 128.2 (2353 objects). We re-detect the intrinsic HI absorption line in UGC 6081 but detect no intervening absorption line systems. We compute a 95% confidence upper limit on the column density frequency distribution function f(N_HI,X) spanning four orders of magnitude in column density, 10^19 (T_s/100 K)(1/f) cm^-2 < N_HI < 10^23 (T_s/100 K)(1/f) cm^-2, that is consistent with previous redshifted optical damped Ly alpha surveys and the aggregate HI 21 cm emission in the local universe. The detection rate is in agreement with extant observations. This pilot survey suggests that an absorption line sear...

  16. Attosecond transient absorption of argon atoms in the vacuum ultraviolet region: line energy shifts versus coherent population transfer

    Cao, Wei; Warrick, Erika R.; Neumark, Daniel M.; Leone, Stephen R.

    2016-01-01

    Using attosecond transient absorption, the dipole response of an argon atom in the vacuum ultraviolet (VUV) region is studied when an external electromagnetic field is present. An isolated attosecond VUV pulse populates Rydberg states lying 15 eV above the argon ground state. A synchronized few-cycle near infrared (NIR) pulse modifies the oscillating dipoles of argon impulsively, leading to alterations in the VUV absorption spectra. As the NIR pulse is delayed with respect to the VUV pulse, multiple features in the absorption profile emerge simultaneously including line broadening, sideband structure, sub-cycle fast modulations, and 5-10 fs slow modulations. These features indicate the coexistence of two general processes of the light-matter interaction: the energy shift of individual atomic levels and coherent population transfer between atomic eigenstates, revealing coherent superpositions. An intuitive formula is derived to treat both effects in a unifying framework, allowing one to identify and quantify the two processes in a single absorption spectrogram.

  17. Absorption solar cooling systems using optimal driving temperatures

    The optimum instantaneous driving temperature of a solar cooling facility is determined along a day. The chillers compared use single effect cycles working with NH3/LiNO3, either conventional or hybridised by incorporating a low pressure booster compressor. Their performances are compared with a H2O/LiBr single effect absorption chiller as part of the same solar system. The results of a detailed thermodynamic cycle for the absorption chillers allow synthesizing them in a modified characteristic temperature difference model. The day accumulated solar cold production is determined using this optimum temperature during two sunny days in mid-July and mid-September, located in Madrid, Spain. The work shows the influences of operational variables and a striking result: selection of a time-constant temperature during all the day does not necessarily imply a substantial loss, being the temperature chosen a key parameter. The results indicate that the NH3/LiNO3 option with no boosting offers a smaller production above-zero Celsius degrees temperatures, but does not require higher hot water driving temperatures than H2O/LiBr. The boosted cycle offers superior performance. Some operational details are discussed. - Highlights: • Instantaneous optimum driving temperature tg,op for solar cooling in Madrid. • 3 absorption cycles tested: H2O/LiBr and NH3/LiNO3 single effect and hybrid. • The tg,op of the hybrid cycle is 16 °C lower than both single effect cycles. • The best fixed driving temperature can reach almost the same behaviour than tg,op

  18. Narrow CIV lambda 1549A Absorption Lines in Moderate-Redshift Quasars

    Vestergaard, Marianne

    2001-01-01

    A large, high-quality spectral data base of well-selected, moderate-redshift radio-loud and radio-quiet quasars is used to characterize the incidence of narrow associated CIV lambda 1549 absorption, and how this may depend on some quasar properties, including radio-type. Preliminary results of this...

  19. Time-dependent excitation and ionization modelling of absorption-line variability due to GRB080310

    Vreeswijk, P.M.; De Cia, A.; Jakobsson, P.;

    2013-01-01

    We model the time-variable absorption of Feii, Feiii, Siii, Cii and Crii detected in Ultraviolet and Visual Echelle Spectrograph (UVES) spectra of gamma-ray burst (GRB) 080310, with the afterglow radiation exciting and ionizing the interstellar medium in the host galaxy at a redshift of z = 2.427...

  20. Absorber-evaporator unit for an absorption-refrigeration system

    Hallatt, R.J.; Rorschach, R.L.

    1965-01-26

    This low temperature absorption-refrigeration system uses an absorber-evaporator. A conduit is connected between the upper portion of the absorber and the lower portion of the evaporator to conduct inert gas from the absorber to the evaporator. A second conduit connects the upper portion of the evaporator to the lower portion of the absorber and a blower in this conduit circulates the inert gas through the closed system. By placing the blower between the evaporator ad the absorber, the pressure in the evaporator is maintained at a minimum so that the working temperature is as low as possible. The medium to be cooled by the refrigerant is circulated through a heat exchanger located within the evaporator, whereby the latent heat of vaporization of the liquid refrigerant is employed to cool the outside medium. (2 claims)

  1. The Lyman limit absorption system in the spectrum of PKS 2126-158 - Heavy-element abundance at high redshift

    The heavy element composition of a Lyman limit absorption system at z(abs) = 2.9676 in the spectrum of PKS 2126 - 158 is studied. Early observations had suggested that this absorption system had no detectable lines of heavy elements. However, new observations reveal weak associated lines due to C IV and C II. Photoionization models show that the system has a C/H abundance ratio = -2.3 + or - 0.2 and an Si/H abundance ratio less than -2.3. The possibility that the z(abs) = 2.9676 system in PKS 2126 - 158 is produced in galactic halo material or by primitive gas-rich dwarf galaxies is discussed. 17 refs

  2. Measurement of water vapor line strengths in the 1.4-2.7 μm range by tunable diode laser absorption spectroscopy

    Pogány, Andrea; Klein, Alexander; Ebert, Volker

    2015-11-01

    Line strengths of nine water vapor absorption lines in the wavelength range between 1.37 and 2.71 μm with line strengths of 10-23-10-20 cm/molecule have been measured using direct tunable diode laser absorption spectroscopy (dTDLAS). Four different light sources were used: three distributed feedback (DFB) diode lasers with wavelengths of 1.37 μm, 2.55 μm and 2.71 μm for measuring one application-specifically selected absorption line with each laser, and a vertical-cavity surface-emitting laser (VCSEL) radiating around 1.39 μm for the measurement of six further absorption lines. Despite the different light sources and line strengths, a uniform measurement and data evaluation method was developed and applied to all lines, and the experimental set-up was kept as similar as possible. This allows a thorough and uniform uncertainty analysis and evaluation of the contributions of the individual experimental parameters to the uncertainty of the derived line strengths. A comprehensive and transparent uncertainty analysis is given for the measurements. Uncertainties of our measured line strengths are in the 1.1-2.5% range (k=2, 95% confidence level). Our measured line strength values agree well with line strengths in the HITRAN 2012 database and other literature sources, we realized lower uncertainties up to a factor of 5-10.

  3. Highly Ionized Fe-K Absorption Line from Cygnus X-1 in the High/Soft State Observed with Suzaku

    Yamada, S; Mineshige, S; Ueda, Y; Kubota, A; Gandhi, P; Done, C; Noda, H; Yoshikawa, A; Makishima, K

    2013-01-01

    We present observations of a transient He-like Fe K alpha absorption line in Suzaku observations of the black hole binary Cygnus X-1 on 2011 October 5 near superior conjunction during the high/soft state, which enable us to map the full evolution from the start and the end of the episodic accretion phenomena or dips for the first time. We model the X-ray spectra during the event and trace their evolution. The absorption line is rather weak in the first half of the observation, but instantly deepens for ~10 ks, and weakens thereafter. The overall change in equivalent width is a factor of ~3, peaking at an orbital phase of ~0.08. This is evidence that the companion stellar wind feeding the black hole is clumpy. By analyzing the line with a Voigt profile, it is found to be consistent with a slightly redshifted Fe XXV transition, or possibly a mixture of several species less ionized than Fe XXV. The data may be explained by a clump located at a distance of ~10^(10-12) cm with a density of ~10^((-13)-(-11)) g cm^-...

  4. Cauchois and S\\'en\\'emaud Tables of wavelengths of X-ray emission lines and absorption edges

    Jonnard, Philippe; 10.1002/xrs.1293

    2011-01-01

    We present the Cauchois and S\\'en\\'emaud Tables of X-ray emission lines and absorption edges. They are written both in French and English. They were published in 1978 by Pergamon Press and are insufficiently known. However they are of large interest because of their completeness. They comprise the energies of all the K, L, M, N and O emission lines of natural elements from lithium up to uranium as well as the energies of satellite emissions and absorption discontinuities. The more intense lines of radio-elements up to fermium (Z = 100) are also given. The Tables range from the hard X-rays (122 keV, 0.01 nm) to the extreme ultra-violet (12 eV, 102 nm). For each transition, the wavelength ({\\AA} and uX) and energy (eV and Ry) are given and references are indicated. The transitions are grouped by increasing wavelength (decreasing photon energy) and also by element and spectral series. We present, as an example, the use of the Tables to identify the emissions of the molybdenum L spectrum. We decided to scan the C...

  5. RTFAS on-line film analysis system

    The control organization of calculating processes in the RTFAS on-line film analysis system is considered. The system realizes a primary image data processing and comprises scanning-measuring projectors, PDP-8 mini-computer, central DEC-10 computer and asynchronous computer networks, connecting DEC-10 and mini computers. Considerable attention has been given to the problems of soft-ware functioning of the central computer. The organization of the system soft-ware is based on the following conceptions: regular usage of the soft-ware functional decomposition, organization of DEC-10 computer calculating processes by the asynchronous principle of control of the system functioning and introducing an abstract projector, i.e. drifting in the mini-computer of all functions of the program processor. The technological structure of the system software is described in detail which is subdivided into three levels: administrative, technological and local. Basic functions of the administrative level, being common for the whole system, are concentrated in the operational program, which is the expansion of the DEC-10 computer operational system. At the technological level the system soft-ware comprises organizing programs, transport stations and program data control. All local control problems are solved by mini-computers. The discipline of the RTFAS system resources scheduling at the DEC-10 computer is considered. The organization of the resources distribution mode is based on service information base data and on using standard means of the DEC-10 computer operational system. The correctness and efficiency of the control organisation of calculating processes is confirmed by the practice of RTFAS system operation

  6. X-ray absorption lines - Signature for preheat level in non-explosive laser implosions

    Yaakobi, B.; McCrory, R. L.; Skupsky, S.; Delettrez, J. A.; Bourke, P.; Soures, J. M.; Hooper, C. F.; Deckman, H.

    1980-08-01

    The measured X-ray spectrum from thick glass shells imploded with two TW six-beam laser pulses displayed absorption by transitions of Si ions. This indicates the existence around the time of peak compression of a cooler (less than approximately 200 eV) layer surrounding the hot innermost glass layer, of density times thickness approximately 0.0006 g/sq cm. This temperature is indicative of the preheat level ealier in the implosion.

  7. Infra-red collision-induced and far-line absorption in dense CO atmospheres

    Wordsworth, R.; Forget, F.; Eymet, Vincent

    2010-01-01

    Abstract Collision-induced absorption is of great importance to the overall radiative budget in dense CO2-rich atmospheres, but its representation in climate models remains uncertain, mainly due to a lack of accurate experimental and theoretical data. Here we compare several parameterisations of the effect, including a new one that makes use of previously unused measurements in the 1200 to 1800 cm-1 spectral range. We find that a widely used parameterisation strongly overestimates ...

  8. Investigation of the magnetic and temperature sensitivity of the Stokes parameters of absorption lines in the solar photosphere

    Sheminova, V A

    2012-01-01

    Response functions to perturbations in the temperature, pressure, microturbulent velocity, and magnetic intensity were calculated for the Stokes parameter profiles of the lines Fe I 525.06, 525.02 and Fe II 614.92 nm. The procedure proposed by Grossmann-Doerth, Larsson, and Solanki (1988) was used. We show that the depression response functions may be used not only to determine the depths at which changes in the physical conditions affect most effectively the absorption and emission in the continuum and in lines, but to estimate the response of Stokes profiles as well. The response was estimated using sensitivity indicators calculated as an integral of the response function over all photospheric layers. An anomalous temperature sensitivity was found for the Stokes profiles in lines with high excitation and ionization potentials such as the lines of O I, C I, Fe II. The depression of such lines increases rather than decreases with growing temperature. The magnetic sensitivity of Stokes profiles depends primari...

  9. An Exploratory Chandra Survey of a Well-Defined Sample of 35 Large Bright Quasar Survey Broad Absorption Line Quasars

    Gallagher, S. C.; Brandt, W. N.; Chartas, G.; Priddey, R.; Garmire, G.P.; Sambruna, R. M.

    2006-01-01

    We present 4-7 ks Chandra observations of 35 Broad Absorption Line (BAL) quasars from the Large Bright Quasar Survey, the largest sample of sensitive, 0.5-8.0 keV X-ray observations of this class of quasars to date. The limited ranges in both redshift (z=1.42-2.90) and UV luminosity (a factor of ~12) of the sample also make it relatively uniform. Of 35 targets, 27 are detected for a detection fraction of 77%, and we confirm previous studies that find BAL quasars to be generally X-ray weak. Fi...

  10. Low-z MgII Broad Absorption-Line Quasars from the Sloan Digital Sky Survey

    Zhang, Shaohua; Wang, Ting-Gui; Wang, Huiyuan; Zhou, Hongyan; Xiao-Bo~Dong; Wang, Jian-Guo

    2010-01-01

    We present a sample of 68 low-z MgII low-ionization broad absorption-line (loBAL) quasars. The sample is uniformly selected from the SDSS5 according to the following criteria: (1) 0.4 1600 \\kms. The last criterion is a trade-off between the completeness and consistency with respect to the canonical definition of BAL quasars that have the `balnicity index' BI>0 in CIV BAL. We adopted such a criterion to ensure that ~90% of our sample are classical BAL quasars and the completeness is ~80%, base...

  11. Measurement of storage time, estimation of ion number and study of absorption line profile in a Paul trap

    Soumen Bhattacharyya; Anita Gupta; S G Nakhate; Pushpa M Rao

    2006-12-01

    Europium (Eu+) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu+ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions. The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both experimentally and theoretically.

  12. Optical performance and metallic absorption in nanoplasmonic systems.

    Arnold, Matthew D; Blaber, Martin G

    2009-03-01

    Optical metrics relating to metallic absorption in representative plasmonic systems are surveyed, with a view to developing heuristics for optimizing performance over a range of applications. We use the real part of the permittivity as the independent variable; consider strengths of particle resonances, resolving power of planar lenses, and guiding lengths of planar waveguides; and compare nearly-free-electron metals including Al, Cu, Ag, Au, Li, Na, and K. Whilst the imaginary part of metal permittivity has a strong damping effect, field distribution is equally important and thus factors including geometry, real permittivity and frequency must be considered when selecting a metal. Al performs well at low permittivities (e.g. sphere resonances, superlenses) whereas Au & Ag only perform well at very negative permittivities (shell and rod resonances, LRSPP). The alkali metals perform well overall but present engineering challenges. PMID:19259225

  13. Emergence of a Broad-Absorption-Line Outflow in the Narrow-line Seyfert 1 Galaxy WPVS 007

    Leighly, Karen M; Casebeer, Darrin A; Grupe, Dirk

    2009-01-01

    We report results from a 2003 FUSE observation, and reanalysis of a 1996 HST observation of the unusual X-ray transient Narrow-line Seyfert 1 galaxy WPVS 007. The HST FOS spectrum revealed mini-BALs with V_max ~ 900 km s^-1 and FWHM ~ 550 km s^-1. The FUSE spectrum showed that an additional BAL outflow with V_max ~ 6000 km s^-1 and FWHM ~ 3400 km s^-1 had appeared. WPVS 007 is a low-luminosity object in which such a high velocity outflow is not expected; therefore, it is an outlier on the M_V/V_max relationship. Template spectral fitting yielded apparent ionic columns, and a Cloudy analysis showed that the presence of PV requires a high ionization parameter log(U) >= 0 and high column density log(N_H) >= 23 assuming solar abundances and a nominal SED for low-luminosity NLS1s with alpha_ox=-1.28. A recent long Swift observation revealed the first hard X-ray detection and an intrinsic (unabsorbed) alpha_ox ~ -1.9$. Using this SED in our analysis yielded lower column density constraints (log(N_H) >= 22.2 for Z=1...

  14. Gas Absorption in the KH 15D System: Further Evidence for Dust Settling in the Circumbinary Disk

    Lawler, S. M.; Herbst, W.; Redfield, S.; Hamilton, C. M.; Johns-Krull, C. M.; Winn, J. N.; Johnson, J.A.; Mundt, R.

    2010-01-01

    Na I D lines in the spectrum of the young binary KH 15D have been analyzed in detail. We find an excess absorption component that may be attributed to foreground interstellar absorption, and to gas possibly associated with the solids in the circumbinary disk. The derived column density is log $N_{\\rm Na\\,\\mathsc{i}}$ = 12.5 cm–2, centered on a radial velocity that is consistent with the systemic velocity. Subtracting the likely contribution of the interstellar medium leaves log $N_{\\rm Na\\,\\m...

  15. The boron absorption line at 2089.6 AA in HD 140283 ?

    Thoren, P H

    2000-01-01

    We have observed the B I line at 2089.6 AA in the metal poor star HD 140283 with HST/STIS. The observation was an attempt to confirm the B abundances derived from the 2497 AA B I line in earlier works in general, and for for this star in particular (Edvardsson et al. 1994 A&A 290, 176; Kiselman & Carlsson 1996, A&A 311, 680). The resulting spectrum gained from 8 orbits of observations is hardly consistent with the boron abundance derived in the earlier works. A pure 10^B line could produce the feature observed but no reasonable process can produce such a ratio between 10^B and 11^B. More likely the analysed feature is affected by a statistical fluctuation. A conservative upper limit estimate of the NLTE corrected boron abundance gives a value marginally consistent with that derived from the 2497 AA line. We are proposing further observations to derive a more definite abundance from the line.

  16. Understanding Absorptive Capacities is an "Innovation Systems" Context

    Narula, Rajneesh

    2004-01-01

    . We also undertake to explain how the nature ofabsorptive capacity changes with stages of economic development, and the importance of thedifferent aspects of absorptive capability at different stages. The relationship is not a linear one:the benefits that accrue from marginal increases in absorptive...... capability change over time.Finally, we provide a tentative and preliminary conceptual argument of how the different stagesof absorptive capacity are related to productivity growth, economic growth and employmentcreation.Key words: New economy, absorptive capacity, knowledge......This paper seeks to broaden our understanding of the concept underlying absorptive capacity atthe macro -level, paying particular attention to the growth and development perspectives. Weprovide definitions of absorptive and technological capacity, external technology flows,productivity growth...

  17. An accelerated line-by-line option for MODTRAN combining on-the-fly generation of line center absorption within 0.1 cm-1 bins and pre-computed line tails

    Berk, Alexander; Conforti, Patrick; Hawes, Fred

    2015-05-01

    A Line-By-Line (LBL) option is being developed for MODTRAN6. The motivation for this development is two-fold. Firstly, when MODTRAN is validated against an independent LBL model, it is difficult to isolate the source of discrepancies. One must verify consistency between pressure, temperature and density profiles, between column density calculations, between continuum and particulate data, between spectral convolution methods, and more. Introducing a LBL option directly within MODTRAN will insure common elements for all calculations other than those used to compute molecular transmittances. The second motivation for the LBL upgrade is that it will enable users to compute high spectral resolution transmittances and radiances for the full range of current MODTRAN applications. In particular, introducing the LBL feature into MODTRAN will enable first-principle calculations of scattered radiances, an option that is often not readily available with LBL models. MODTRAN will compute LBL transmittances within one 0.1 cm-1 spectral bin at a time, marching through the full requested band pass. The LBL algorithm will use the highly accurate, pressure- and temperature-dependent MODTRAN Padé approximant fits of the contribution from line tails to define the absorption from all molecular transitions centered more than 0.05 cm-1 from each 0.1 cm-1 spectral bin. The beauty of this approach is that the on-the-fly computations for each 0.1 cm-1 bin will only require explicit LBL summing of transitions centered within a 0.2 cm-1 spectral region. That is, the contribution from the more distant lines will be pre-computed via the Padé approximants. The status of the LBL effort will be presented. This will include initial thermal and solar radiance calculations, validation calculations, and self-validations of the MODTRAN band model against its own LBL calculations.

  18. A CCD-based system for the detection of DNA in electrophoresis gels by UV absorption

    A method and apparatus for the detection and quantification of large fragments of unlabelled nucleic acids in agarose gels is presented. The technique is based on ultraviolet (UV) absorption by nucleotides. A deuterium source illuminates individual sample lanes of an electrophoresis gel via an array of optical fibres. As DNA bands pass through the illuminated region of the gel the amount of UV light transmitted is reduced because of absorption by the DNA. During electrophoresis the regions of DNA are detected on-line using a UV-sensitive charge coupled device (CCD). As the absorption coefficient is proportional to the mass of DNA the technique is inherently quantitative. The mass of DNA in a region of the gel is approximately proportional to the integrated signal in the corresponding section of the CCD image. This system currently has a detection limit of less than 1.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. In addition the DNA sample remains in its native state. The removal of the carcinogenic dye from the detection procedure greatly reduces associated biological hazards. (author)

  19. WEAK HARD X-RAY EMISSION FROM TWO BROAD ABSORPTION LINE QUASARS OBSERVED WITH NuSTAR: COMPTON-THICK ABSORPTION OR INTRINSIC X-RAY WEAKNESS?

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain ≈400-600 hard X-ray (∼> 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (NH ∼24 cm–2). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be NH ≈ 7 × 1024 cm–2 if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe Kα line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%

  20. Weak Hard X-Ray Emission from Two Broad Absorption Line Quasars Observed with NuStar: Compton-Thick Absorption or Intrinsic X-Ray Weakness?

    Luo, B.; Brandt, W. N.; Alexander, D. M.; Harrison, F. A.; Stern, D.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W..; Fabian, A. C.; Farrah, D.; Fiore, F.; Fuerst, F.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R.; Madsen, K. K.; Matt, G.; Ogle, P.; Risaliti, G.; Saez, C.; Teng, S. H.; Walton, D. J.; Zhang, W. W.

    2013-01-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain approx. or equal to 400-600 hard X-ray (is greater than or equal to 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed N(sub H) is less than or equal to 10(exp24) cm(exp-2). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N(sub H) 7 × 10(exp 24) cm(exp-2) if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe Ka line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

  1. WEAK HARD X-RAY EMISSION FROM TWO BROAD ABSORPTION LINE QUASARS OBSERVED WITH NuSTAR: COMPTON-THICK ABSORPTION OR INTRINSIC X-RAY WEAKNESS?

    Luo, B.; Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Alexander, D. M.; Hickox, R. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Harrison, F. A.; Fuerst, F.; Grefenstette, B. W.; Madsen, K. K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Bauer, F. E. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Comastri, A. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Fiore, F. [Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone (Italy); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Matt, G. [Dipartimento di Matematica e Fisica, Universita degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Ogle, P. [IPAC, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States); and others

    2013-08-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain Almost-Equal-To 400-600 hard X-ray ({approx}> 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (N{sub H} {approx}< 10{sup 24} cm{sup -2}). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N{sub H} Almost-Equal-To 7 Multiplication-Sign 10{sup 24} cm{sup -2} if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe K{alpha} line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

  2. Monte Carlo inversion of hydrogen and metal lines from QSO absorption spectra

    Levshakov, S A; Kegel, W H; Levshakov, Sergei A.; Agafonova, Irina I.; Kegel, Wilhelm H.

    2000-01-01

    A new method, based on the simulated annealing algorithm and aimed at theinverse problem in the analysis of intergalactic (interstellar) complex spectraof hydrogen and metal lines, is presented. We consider the process of lineformation in clumpy stochastic media accounting for fluctuating velocity anddensity fields (mesoturbulence). This approach generalizes our previous ReverseMonte Carlo and Entropy-Regularized Minimization methods which were applied tovelocity fluctuations only. The method allows one to estimate, from an observedsystem of spectral lines, both the physical parameters of the absorbing gas andappropriate structures of the velocity and density distributions along the lineof sight. The validity of the computational procedure is demonstrated using aseries of synthetic spectra that emulate the up-to-date best quality data. HI,CII, SiII, CIV, SiIV, and OVI lines, exhibiting complex profiles, were fittedsimultaneously. The adopted physical parameters have been recovered with asufficiently high accu...

  3. Invisible Active Galactic Nuclei. II Radio Morphologies & Five New HI 21 cm Absorption Line Detections

    Yan, Ting; Stocke, John T.; Darling, Jeremy; Momjian, Emmanuel; Sharma, Soniya; Kanekar, Nissim

    2015-01-01

    We have selected a sample of 80 candidates for obscured radio-loud active galactic nuclei and presented their basic optical/near-infrared (NIR) properties in Paper 1. In this paper, we present both high-resolution radio continuum images for all of these sources and HI 21cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz VLA continuum observations find that 52 sources are compact or have substantial compact components with size

  4. Weak Hard X-Ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-Ray Weakness

    Luo, B.; Brandt, W. N.; Alexander, D. M.;

    2014-01-01

    We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z 330 times weaker than...... are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (Γeff ≈ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X...... expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL...

  5. Indium determination by spectral overlappings of lines in atomic absorption spectrometry

    A molybdenum hollow-cathode lamp filled with neon can be used to determine indium. Characteristic concentration for this element is 4.5 mg/L in the 325 nm spectral region for the Mo(I) 325.621 nm line. In addition, values of 0.4 mg/L and 0.3 mg/L are obtained with the Mo(I) 410.215 nm and Ne(I) 451.151 nm lines, respectively. These spectral overlappings allow the determination of indium in silver-cadmium-indium alloys. (Author)

  6. On-line analytical processing with conceptual information systems

    Stumme, Gerd

    1998-01-01

    A conceptual information system consists of a database together with conceptual hierarchies. The management system TOSCANA visualizes arbitrary combinations of conceptual hierarchies by nested line diagrams and allows an on-line interaction with a database to analyze data conceptually. The paper describes the conception of conceptual information systems and discusses the use of their visualization techniques for on-line analytical processing (OLAP).

  7. Nature and statistical properties of quasar associated absorption systems in the XQ-100 Legacy Survey

    Perrotta, Serena; Prochaska, J Xavier; Cristiani, Stefano; Cupani, Guido; Ellison, Sara; Lòpez, Sebastian; Becker, George D; Berg, Trystyn A M; Christensen, Lise; Denney, Kelly D; Hamann, Frederick; Pâris, Isabelle; Vestergaard, Marianne; Worseck, Gábor

    2016-01-01

    We statistically study the physical properties of a sample of narrow absorption line (NAL) systems looking for empirical evidences to distinguish between intrinsic and intervening NALs without taking into account any a priori definition or velocity cut-off. We analyze the spectra of 100 quasars with 3.5 < z$\\rm_{em}$ < 4.5, observed with X-shooter/VLT in the context of the XQ-100 Legacy Survey. We detect a $\\sim$ 8 $\\sigma$ excess in the number density of absorbers within 10,000 km/s of the quasar emission redshift with respect to the random occurrence of NALs. This excess does not show a dependence on the quasar bolometric luminosity and it is not due to the redshift evolution of NALs. It extends far beyond the standard 5000 km/s cut-off traditionally defined for associated absorption lines. We propose to modify this definition, extending the threshold to 10,000 km/s when also weak absorbers (equivalent width < 0.2 \\AA) are considered. We infer NV is the ion that better traces the effects of the qua...

  8. INTERSTELLAR H I AND H2 IN THE MAGELLANIC CLOUDS: AN EXPANDED SAMPLE BASED ON ULTRAVIOLET ABSORPTION-LINE DATA

    We have determined column densities of H I and/or H2 for sight lines in the Magellanic Clouds from archival Hubble Space Telescope and Far-Ultraviolet Spectroscopic Explorer spectra of H I Lyα and H2 Lyman-band absorption. Together with some similar data from the literature, we now have absorption-based N(H I) and/or N(H2) for 285 Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) sight lines (114 with a detection or limit for both species)—enabling more extensive, direct, and accurate determinations of molecular fractions, gas-to-dust ratios, and elemental depletions in these two nearby, low-metallicity galaxies. For sight lines where the N(H I) estimated from 21 cm emission is significantly higher than the value derived from Lyα absorption (presumably due to emission from gas beyond the target stars), integration of the 21 cm profile only over the velocity range seen in Na I or H2 absorption generally yields much better agreement. Conversely, N(21 cm) can be lower than N(Lyα) by factors of 2-3 in some LMC sight lines—suggestive of small-scale structure within the 21 cm beam(s) and/or some saturation in the emission. The mean gas-to-dust ratios obtained from N(Htot)/E(B – V) are larger than in our Galaxy, by factors of 2.8-2.9 in the LMC and 4.1-5.2 in the SMC—i.e., factors similar to the differences in metallicity. The N(H2)/E(B – V) ratios are more similar in the three galaxies, but with considerable scatter within each galaxy. These data may be used to test models of the atomic-to-molecular transition at low metallicities and predictions of N(H2) based on comparisons of 21 cm emission and the IR emission from dust.

  9. On line protection systems for induction motors

    Protection of induction motors is very important since they are widely used in industry for many applications due to their high robustness, reliability, low cost and maintenance, high efficiency and long service life. So, protecting these motors is crucial for operations. This paper presents a combined protection approach for induction motors. To achieve this, the electrical values of the induction motor were measured with sensitivity ±1% through a data acquisition card and processed with software developed in Visual C++. An on line protection system for induction motors was achieved easily and effectively. The experimental results have shown that the induction motor was protected against the possible problems faced during the operation. The software developed for this protection provides flexible and reliable media for operators and their motors. It is expected that the motor protection achieved in this study might be faster than the classical techniques and also may be applied to larger motors easily after small modifications of the software

  10. Evidence for ultra-fast outflows in radio-quiet AGNs: I - detection and statistical incidence of Fe K-shell absorption lines

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G.G.C.; Yaqoob, T.; Braito, V.; Dadina, M.

    2010-01-01

    We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies E>7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3x10^-8, and their detection have been independently confirmed by a spectral analysis of the MOS dat...

  11. Modelling High Resolution Absorption Spectra with ExoMolLine Lists: NH3and CH4

    Barton, E. J.; Yurchenko, S. N.; Tennyson, J.;

    [1]. For this reason, a smart collaboration has been established between Optical Diagnostics Group at DTU and ExoMol, to combine high resolution spectra measured at elevated temperatures and empirically tuned ab initio methods to produce suitable molecular line lists for modelling molecules in...

  12. PHYSICAL CONDITIONS IN ORION'S VEIL. III. UV IRON ABSORPTION LINES TOWARD Θ1B ORIONIS

    We have used archival Space Telescope Imaging Spectrograph (STIS) data in the range 2100-2500 A toward the Trapezium star Θ1 B Orionis (HD 37021) to estimate the Fe column density and other parameters in the neutral Veil of Orion. The Veil lies 1-3 pc in front of the Orion H+ region, it has an estimated volume density of 102.5-3.5 cm-3, and its H0 column density has been previously measured via the STIS-observed Lyα line. We find N(Fe)/N(H0) = 4.4 ± 1.3 x 10-7, implying a log depletion of -1.81 ± 0.13 relative to solar. Our estimate of N(Fe) comes from direct integration of the moderate optical depth Fe II λ2249 and λ2260 lines. From this analysis, we are also able to estimate empirically new values for the oscillator strengths of the low optical depth Fe II λ2234 and λ2367 lines. N(Fe)/N(H) in the Veil is consistent with the most recent estimates of this ratio for the main Orion H+ region. Therefore, there is no evidence that significant Fe has been released from grains into the gaseous state in the H+ region via grain destruction processes. The Fe/H ratio in the Veil is also comparable to other Fe/H measurements made in the diffuse interstellar medium for lower density gas. Therefore, the present result suggests that depletion is not strongly correlated with local gas density at least up to n ∼ 103 cm-3. Finally, we have identified several outlying velocity components in some of the Fe II line profiles, components that have been previously identified in optical Ca II and Na I line profiles. These outlying velocity components are probably small concentrations of cold neutral material lying tens of pc or more in front of the Veil and unrelated to it.

  13. NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. V. NONLINEAR ABSORPTION-LINE INDEX VERSUS METALLICITY RELATIONS AND BIMODAL INDEX DISTRIBUTIONS OF M31 GLOBULAR CLUSTERS

    Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Such division of extragalactic GCs, so far asserted mainly by photometric color bimodality, has been viewed as the presence of merely two distinct metallicity subgroups within individual galaxies and forms a critical backbone of various galaxy formation theories. Given that spectroscopy is a more detailed probe into stellar population than photometry, the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We take this as a close analogy to the recent view that metallicity-color nonlinearity is primarily responsible for observed GC color bimodality. We also demonstrate that the metallicity-sensitive magnesium line displays non-negligible metallicity-index nonlinearity and Balmer lines show rather strong nonlinearity. This gives rise to bimodal index distributions, which are routinely interpreted as bimodal metallicity distributions, not considering metallicity-index nonlinearity. Our findings give a new insight into the constitution of M31's GC system, which could change much of the current thought on the formation of GC systems and their host galaxies.

  14. Thermodynamic analysis and comparison of combined ejector–absorption and single effect absorption refrigeration systems

    Highlights: • Ammonia/LiNO3 and ammonia/NaSCN combined ejector–absorption refrigeration cycles are analyzed. • The performance of combined cycles is compared to that of single effect cycles. • Ejector is used to facilitate pressure recovery of the absorber and improve mixing. • For low generator temperatures combined cycles have better performance. • Influence of various operating parameters on performance of cycles is investigated. - Abstract: Alternatives to ammonia/water absorption refrigeration cycles that have no need for purification include ammonia/LiNO3 and ammonia/NaSCN cycles. Similar to the other absorption refrigeration cycles they have low coefficients of performance and exergy efficiencies at low generator temperatures. Combined single effect cycles can reduce this problem. In these cycles the solution expansion valve is replaced with an ejector to allow for pressure recovery from the absorber and to enhance mixing of the weak solution and refrigerant vapor from the evaporator. Simulations are used to examine the influence of various operating parameters on performance and the possibility of crystallization in these cycles, and to compare their performances with single effect cycles. It is shown that the combined cycles have better performance than single effect ones at low generator temperatures

  15. Sulfur K-edge absorption spectroscopy on selected biological systems

    Sulfur is an essential element in organisms. In this thesis investigations of sulfur compounds in selected biological systems by XANES (X-ray Absorption Near Edge Structure) spectroscopy are reported. XANES spectroscopy at the sulfur K-edge provides an excellent tool to gain information about the local environments of sulfur atoms in intact biological samples - no extraction processes are required. Spatially resolved measurements using a Kirkpatrick-Baez mirror focusing system were carried out to investigate the infection of wheat leaves by rust fungi. The results give information about changes in the sulfur metabolism of the host induced by the parasite and about the extension of the infection into visibly uninfected plant tissue. Furthermore, XANES spectra of microbial mats from sulfidic caves were measured. These mats are dominated by microbial groups involved in cycling sulfur. Additionally, the influence of sulfate deprivation and H2S exposure on sulfur compounds in onion was investigated. To gain an insight into the thermal degradation of organic material the influence of roasting of sulfur compounds in coffee beans was studied. (orig.)

  16. Discovery of two broad absorption line quasars at redshift about 4.75 using the Lijiang 2.4m telescope

    Yi, WeiMin; Wang, FeiGe; Yang, JinYi; Yang, Qian; Bai, JinMing

    2015-01-01

    The ultraviolet broad absorption lines have been seen in the spectra of quasars at high redshift, and are generally considered to be caused by outflows with velocities from thousands kilometers per second to one tenth of the speed of light. They provide crucial implications for the cosmological structures and physical evolutions related to the feedback of active galactic nuclei (AGNs). Recently, through a dedicated program of optically spectroscopic identifications of selected quasar candidates at redshift 5 by using the Lijiang 2.4 m telescope, we discovered two luminous broad absorption line quasars (BALQSOs) at redshift about 4.75. One of them may even have the potentially highest absorption Balnicity Index (BI) ever found to date, which is remarkably characterized by its deep, broad absorption lines and sub-relativistic outflows. Further physical properties, including the metal abundances, variabilities, evolutions of the supermassive black holes (SMBH) and accretion disks associated with the feedback pro...

  17. Line Transfer through Clumpy, Large-Scale Outflows: Lyman Alpha Absorption and Halos around Starforming Galaxies

    Dijkstra, Mark

    2012-01-01

    We present constrained radiative transfer calculations of Lyman Alpha (Lya) photons propagating through clumpy, dusty, large scale outflows, and explore whether we can quantitatively explain the Lya halos that have been observed around Lyman Break Galaxies. We construct phenomenological models of large-scale outflows which consist of cold clumps that are in pressure equilibrium with a constant-velocity hot wind. First we consider models in which the cold clumps are distributed symmetrically around the galaxy, and in which the clumps undergo a continuous acceleration in its 'circumgalactic' medium (CGM). We constrain the properties of the cold clumps (radius, velocity, HI column density, & number density) by matching the observed Lya absorption strength of the CGM in the spectra of background galaxies. We then insert a Lya source in the center of this clumpy outflow, which consists of 1e5-1e6 clumps, and compute observable properties of the scattered Lya photons. In these models, the scattered radiation fo...

  18. Sodium Absorption Systems towards SN Ia 2014J Originate on Interstellar Scales

    Maeda, K; Kawabata, K S; Foley, R; Honda, S; Moritani, Y; Tanaka, M; Hashimoto, O; Ishigaki, M; Simon, J D; Phillips, M M; Yamanaka, M; Nogami, D; Arai, A; Aoki, W; Nomoto, K; Milisavljevic, D; Mazzali, P A; Soderberg, A M; Schramm, M; Sato, B; Harakawa, H; Morrell, N; Arimoto, N

    2015-01-01

    Na I D absorbing systems towards Type Ia Supernovae (SNe Ia) have been intensively studied over the last decade with the aim of finding circumstellar material (CSM), which is an indirect probe of the progenitor system. However, it is difficult to deconvolve CSM components from non-variable, and often dominant, components created by interstellar material (ISM). We present a series of high resolution spectra of SN Ia 2014J from before maximum brightness to >~250 days after maximum brightness. The late-time spectrum provides unique information for determining the origin of the Na I D absorption systems. The deep late-time observation allows us to probe the environment around the SN at a large scale, extending to >~40 pc. We find that a spectrum of diffuse light in the vicinity, but not directly in the line-of-sight of the SN, has absorbing systems nearly identical to those obtained for the `pure' SN line-of-sight. Therefore, basically all Na I D systems seen towards SN 2014J must originate from foreground materi...

  19. COMPARISON OF ENERGY AND EXERGY EFFICIENCIES OF ABSORPTION REFRIGERATION SYSTEM WITH MECHANICAL COMPRESSION REFRIGERATION SYSTEM

    Gülay YAKAR

    2005-02-01

    Full Text Available In this study, energy and exergy analysis of absorption refrigeration system using LiBr- water and mechanical compression refrigeration system using R134-a were performed at different evaporation temperatures. The results are presented in tables and figures.

  20. Effects of velocity-changing collisions on two-photon and stepwise-absorption spectroscopic line shapes

    We report the results of an experimental study of the effects of velocity-changing collisions on two-photon and stepwise-absorption line shapes. Excitation spectra for the 3S/sub 1/2/ → 3P/sub 1/2/ → 4D/sub 3/2/ transitions of sodium atoms undergoing collisions with foreign gas perturbers are obtained. These spectra are obtained with two cw dye lasers. One laser, the pump laser, is tuned 1.6 GHz below the 3S/sub 1/2/ → 3P/sub 1/2/ transition frequency and excites a nonthermal longitudinal velocity distribution of excited 3P/sub 1/2/ atoms in the vapor. Absorption of the second (probe) laser is used to monitor the steady-state excited-state distribution which is a result of collisions with rare gas atoms. The spectra are obtained for various pressures of He, Ne, and Kr gases and are fit to a theoretical model which utilizes either the phenomenological Keilson-Stoerer or the classical hard-sphere collision kernel. The theoretical model includes the effects of collisionally aided excitation of the 3P/sub 1/2/ state as well as effects due to fine-structure state-changing collisions. Although both kernels are found to predict line shapes which are in reasonable agreement with the experimental results, the hard-sphere kernel is found superior as it gives a better description of the effects of large-angle scattering for heavy perturbers. Neither kernel provides a fully adequate description over the entire line profile. The experimental data is used to extract effective hard-sphere collision cross sections for collisions between sodium 3P/sub 1/2/ atoms and helium, neon, and krypton perturbers

  1. The SLUGGS survey: Globular cluster stellar population trends from weak absorption lines in stacked spectra

    Usher, Christopher; Brodie, Jean P; Romanowsky, Aaron J; Strader, Jay; Conroy, Charlie; Foster, Caroline; Pastorello, Nicola; Pota, Vincenzo; Arnold, Jacob A

    2014-01-01

    As part of the SLUGGS survey, we stack 1137 Keck DEIMOS spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal to noise ratios of $\\sim 90$ \\AA$^{-1}$. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the H$\\alpha$ and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet--colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour--metallicity relation between galaxies. Two possible explanations for the colour--metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stackin...

  2. A Novel Observation of 'a Sharp Absorption Line' Using Much More Broad Laser Lights: Quantum Interference in the Autoionization Spectra of Sc

    The most accurate measurements in physical sciences will be precision spectroscopic experiments which are based on the usage of most narrow lines in cooperation with interference phenomena. We present a novel experimental observation of 'a sharp absorption resonance line' with much more broad laser lights. The mechanism of such a novel phenomenon will be elucidated and its implications will be discussed

  3. Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars

    We present the results of a detailed many-multiplet analysis performed on a new sample of Mg ii systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in α derived from our analysis over the redshift range 0.4≤z≤2.3 is Δα/α=(-0.06±0.06)x10-5. The median redshift of our sample (z≅1.55) corresponds to a look-back time of 9.7 Gyr in the most favored cosmological model today. This gives a 3σ limit, -2.5x10-16≤(Δα/αΔt)≤+1.2x10-16 yr-1, for the time variation of α, that forms the strongest constraint obtained based on high redshift quasar absorption line systems

  4. Study of the Many Fluorescent Lines and the Absorption Variability in GX 301-2 with XMM-Newton

    Fuerst, F.; Suchy, S.; Kreykenbohm, I.; Barragan, L.; Wilms, J.; Pottschmidt, K.; Caballero, I.; Kretschmar, P.; Ferrigno, C.; Rothschild, R. E.

    2011-01-01

    We present an in-depth study of the High Mass X-ray Binary (HMXB) GX 301-2 during its pre-periastron flare using data from the XMM-Newton satellite. The energy spectrum shows a power law continuum absorbed by a large equivalent hydrogen column on the order of 10(exp 24)/ sq cm and a prominent Fe K-alpha fluorescent emission line. Besides the Fe K-alpha line, evidence for Fe K-Beta, Ni K-alpha, Ni K-Beta, S K-alpha, Ar K-alpha, Ca K-alpha, and Cr K-alpha fluorescent lines is found. The observed line strengths are consistent with fluorescence in a cold absorber. This is the first time that Cr K-alpha is seen in emission in the X-ray spectrum of a HMXB. In addition to the modulation by the strong pulse period of approx 685 sec the source is highly variable and shows different states of activity. We perform time-resolved as well as pulse-to-pulse resolved spectroscopy to investigate differences between these states of activity. We find that fluorescent line fluxes are strongly variable and generally follow the overall flux. The N-H value is variable by a factor of 2, but not correlated to continuum normalization. We find an interval of low flux in the light curve in which the pulsations cease almost completely, without any indication of an increasing absorption column. We investigate this dip in detail and argue that it is most likely that during the dip the accretion ceased and the afterglow of the fluorescent iron accounted for the main portion of the X-ray flux. A similar dip was found earlier in RXTE data, and we compare our findings to these results.

  5. The HST quasar absorption line key project. 4: HST faint-object spectrograph and ground-based observations of the unusual low-redshift broad absorption-line quasi-stellar object PG 0043+039

    Turnshek, David A.; Espey, Brian R.; Kopko, Michael, Jr.; Rauch, Michael; Weymann, Ray J.; Jannuzi, Buell T.; Boksenberg, Alec; Bergeron, Jacqueline; Hartig, George F.; Sargent, W. L. W.

    1994-01-01

    Hubble Space Telescope Faint Object Spectrograph (HST FOS) observations have shown that the spectrum of the low-redshift (z(sub em) approximately equal to 0.384) QSO PG 0043+039 exhibits weak broad absorption lines (BALs). The BALs were discovered during the course of UV spectrophotometry made for the HST Quasar Absorption Line Key Project. The HST data are analyzed along with ground-based optical and IUE spectrophotometry. The object is found to have a number of atypical properties relative to normal non-BAL QSOs. The observed continuum is atypical in the sense that it is much weaker than that of a normal optically selected QSO at rest wavelengths approximately less than 2200 A. Intrinsic reddening of E(B-V) approximately equal to 0.11 mag by dust similar to that found in the SMC at the redshift of PG 0043+039 conservatively accounts for the observed continuum shape moderately well. These observed characteristics are typical of low-ionization BAL QSOs, but convincing evidence for BALs due to low-ionization transitions of Mg II, Al III, Al II, or C II does not exist. Therefore, this object may be a misaligned BAL QSO having many of the characteristics of low-ionization BAL QSOs with the sight line passing through a putative dusty region, but evidently missing clouds of high enough column density to produce observable low-ionization BALs. If the intrinsic dust-extinction model is correct, the observations suggest that the dust is not confined to the presumably higher density, low-ionization BAL clouds, but that it has drifted to nearby high-ionization BAL regions. We also consider other possible mechanisms for producing the shape of the continuous energy distribution which cannot be ruled out. We compare the Fe II emission in PG 0043+039 with that in another Key Project QSO, NGC 2841-UB 3, which has optical Fe II emission comparable in strength to that in PG 0043+039, but has anomalously weak UV Fe II emission. In addition, from an analysis of UV and optical

  6. Variable Doppler shifts of the thermal wind absorption lines in low-mass X-ray binaries

    Madej, O K; Trigo, M Diaz; Miskovicova, I

    2013-01-01

    In this paper we address the general applicability of the method pioneered by \\citet{Zhang2012} in which the motion of the compact object can be tracked using wind X-ray absorption lines. We present the velocity measurements of the thermal wind lines observed in the X-ray spectrum of a few low-mass X-ray binaries: GX 13+1, H 1743$-$322, GRO J1655$-$40 and GRS 1915+105. We find that the variability in the velocity of the wind lines in about all of the sources is larger than conceivable radial velocity variations of the compact object. GX 13+1 provides a potential exception, although it would require the red giant star to be massive with a mass of $\\approx 5-6\\ M_{\\odot}$. We conclude that the variability of the source luminosity occurring on a time scale of days/months can affect the outflow properties making it difficult to track the orbital motion of the compact object using current observations. Given the intrinsic variability of the outflows we suggest that low-mass X-ray binaries showing stable coronae in...

  7. X-Ray Weak Broad-Line Quasars: Absorption or Intrinsic X-Ray Weakness

    Risaliti, Guido; Mushotzky, Richard F. (Technical Monitor)

    2004-01-01

    XMM observations of X-ray weak quasars have been performed during 2003. The data for all but the last observation are now available (there has been a delay of several months on the initial schedule, due to high background flares which contaminated the observations: as a consequence, most of them had to be rescheduled). We have reduced and analyzed these data, and obtained interesting preliminary scientific results. Out of the eight sources, 4 are confirmed to be extrimely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confirmed to be highly variable both in flux (by factors 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects, an article is in preparation. Preliminary results have been presented at an international workshop on AGN surveys in December 2003, in Cozumel (Mexico). In order to further understand the nature of these X-ray weak quasars, we submitted proposals for spectroscopy at optical and infrared telescopes. We obtained time at the TNG 4 meter telescope for near-IR observations, and at the Hobby-Eberly Telescope for optical high-resolution spectroscopy. These observations will be performed in early 2004, and will complement the XMM data, in order to understand whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circumnuclear material.

  8. A VLBI survey of compact broad absorption line quasars with balnicity index BI>0

    Kunert-Bajraszewska, M; Katarzynski, K; Roskowinski, C

    2015-01-01

    We performed high resolution radio observations of a new sample of ten BAL quasars using both the VLBA and EVN at 5 GHz. All the selected sources have balnicity indices (BI) more than 0 and radio flux densities less than 80 mJy at 1.4 GHz. They are very compact with linear sizes of the order of a few tens of parsecs and radio luminosities at 1.4 GHz above the FRI-FRII luminosity threshold. Most of the observed objects have been resolved at 5 GHz showing one-sided, probably core-jet structures, typical for quasars. We discuss in detail their age and orientation based on the radio observations. We then used the largest available sample of BAL quasars to study the relationships between the radio and optical properties in these objects. We found that (1) the strongest absorption (high values of the balnicity index BI) is connected with the lower values of the radio-loudness parameter, logR_I<1.5, and thus probably with large viewing angles; (2) the large span of the BI values in each bin of the radio-loudness ...

  9. In-Line Capacitance Sensor for Real-Time Water Absorption Measurements

    Nurge, Mark A.; Perusich, Stephen A.

    2010-01-01

    A capacitance/dielectric sensor was designed, constructed, and used to measure in real time the in-situ water concentration in a desiccant water bed. Measurements were carried out with two experimental setups: (1) passing nitrogen through a humidity generator and allowing the gas stream to become saturated at a measured temperature and pressure, and (2) injecting water via a syringe pump into a nitrogen stream. Both water vapor generating devices were attached to a downstream vertically-mounted water capture bed filled with 19.5 g of Moisture Gone desiccant. The sensor consisted of two electrodes: (1) a 1/8" dia stainless steel rod placed in the middle of the bed and (2) the outer shell of the stainless steel bed concentric with the rod. All phases of the water capture process (background, heating, absorption, desorption, and cooling) were monitored with capacitance. The measured capacitance was found to vary linearly with the water content in the bed at frequencies above 100 kHz indicating dipolar motion dominated the signal; below this frequency, ionic motion caused nonlinearities in the water concentration/capacitance relationship. The desiccant exhibited a dielectric relaxation whose activation energy was lowered upon addition of water indicating either a less hindered rotational motion or crystal reorientation.

  10. The origin of the excess transit absorption in the HD 189733 system: planet or star?

    Barnes, J R; Staab, D; Anglada-Escudé, G

    2016-01-01

    We have detected excess absorption in the emission cores of Ca II H & K during transits of HD 189733b for the first time. Using observations of three transits we investigate the origin of the absorption, which is also seen in H{\\alpha} and the Na I D lines. Applying differential spectrophotometry methods to the Ca II H and Ca II K lines combined, using respective passband widths of {\\Delta}{\\lambda} = 0.4 & 0.6 $\\AA$ yields excess absorption of t$_d$ = 0.0074 $\\pm$ 0.0044 (1.7{\\sigma}; Transit 1) and 0.0214 +/- 0.0022 (9.8{\\sigma}; Transit 2). Similarly, we detect excess H{\\alpha} absorption in a passband of width {\\Delta}{\\lambda} = 0.7 $\\AA$, with t$_d$ = 0.0084 $\\pm$ 0.0016 (5.2{\\sigma}) and 0.0121 $\\pm$ 0.0012 (9.9{\\sigma}). For both lines, Transit 2 is thus significantly deeper. Combining all three transits for the Na I D lines yields excess absorption of t$_d$ = 0.0041 $\\pm$ 0.0006 (6.5{\\sigma}). By considering the time series observations of each line, we find that the excess apparent absorptio...

  11. Influence of the multiple scattering of relativistic electrons on the line width of the backward Parametric X-ray Radiation in the absence of photo absorption

    Tabrizi, Mehdi

    2015-01-01

    The multiple scattering effect on the line width of the backward Parametric X-ray Radiation (PXR) in the extremely Bragg geometry, produced by low energy relativistic electrons traversing a single crystal, is discussed. It is shown that there exist conditions, when the influence of photo absorption on the line width can be neglected, and the only multiple scattering process of relativistic electrons in crystal leads to the PXR lines' broadening. Based on the obtained theoretical and numerical...

  12. A software system for measuring bubble chamber films on line

    A system has been developed for measuring bubble chamber films on line. This report describes the computer program used in the on-line system. The program guides the operator during the measurements, makes on-line control of the measurement data and produces output data on magnetic tape in a format suitable as input for the geometry programme THRESH. The on-line program is coded in the assembly language OSAS-A used for CDC 8090 computers. (Auth.)

  13. The Gaseous Extent of Galaxies and the Origin of \\lya Absorption Systems. III. Hubble Space Telescope Imaging of \\lya-Absorbing Galaxies at z < 1

    Chen, H. -W.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.

    1997-01-01

    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We measure properties of 87 galaxies, of which 33 are associated with corresponding \\lya absorption systems and 24 do not produce corresponding \\lya absorption lines to within sensitive upper limits. Considering only galaxy and absorber pairs that are likely to be physically associated and exc...

  14. VERY LONG BASELINE ARRAY MULTI-FREQUENCY POLARIMETRIC IMAGING OF RADIO-LOUD BROAD ABSORPTION LINE QUASARS

    We conducted the first multi-frequency polarimetric imaging of four broad absorption line (BAL) quasars using the Very Long Baseline Array at milliarcsecond resolutions to investigate the inclination of the nonthermal jet and test the hypothesis that radio sources in BAL quasars are still young. Among these four sources, J0928+446, J1018+0530, and J1405+4056 show one-sided structures in parsec scales and polarized emission detected in the core. These characteristics are consistent with those of blazars. We set constraints on viewing angles to <66° for these jets in the framework of a Doppler beaming effect. J1159+0112 exhibits an unpolarized gigahertz-peaked spectrum component and several discrete blobs with steep spectra on both sides of the central component across ∼1 kpc. These properties are consistent with those of young radio sources. We discuss the structures of jets and active galactic nucleus wind.

  15. Unveiling the Intrinsic X-ray Properties of Broad Absorption Line Quasars with a Relatively Unbiased Sample

    Morabito, Leah K; Leighly, Karen M; Sivakoff, Gregory R; Shankar, Francesco

    2013-01-01

    There is growing evidence of a higher intrinsic fraction of broad absorption line quasars (BALQSOs) than that obtained in optical surveys, on which most previous X-ray studies of BALQSOs have focused. Here we present Chandra observations of 18 BALQSOs at $z\\sim2$, selected from a near-infrared (2MASS) sample, where the BALQSO fraction is likely to be close to the intrinsic fraction. We measure photon indices using the stacked spectra of the optically-faint ($i-K_s\\geq 2.3$ mag) and optically-bright ($i-K_s < 2.3$ mag) samples to be $\\Gamma \\simeq 1.5$--2.1. We constrain their intrinsic column density by modelling the X-ray fractional hardness ratio, finding a mean column density of $3.5\\times10^{22}$ \\cmsq\\ assuming neutral absorption. We incorporate SDSS optical measurements (rest frame UV) to study the broadband spectral index between the X-ray and UV bands, and compare this to a large sample of normal quasars. We find that the optically-faint BALQSOs are X-ray weaker than the optically-bright ones, and ...

  16. XMM-NEWTON OBSERVATIONS OF THE RADIO-LOUD BROAD ABSORPTION LINE QUASAR FBQS J131213.5+231958

    We present XMM-Newton observations of the broad absorption line (BAL) quasar FBQS J131213.5+231958. The X-ray spectrum of the source can be well described by an absorbed power-law model in which the absorber is either ionized or only partially covers the continuum source. This can explain the apparent lack of absorption observed in the Chandra spectrum with low signal-to-noise ratio. While the power-law slope of the spectrum is similar to that of non-BAL radio-loud quasars, the Eddington luminosity ratio is likely to be significantly higher than the mean. This shows that in high-mass black holes (BHs), high Eddington accretion may not result in as steep of a spectrum as in lower-mass BHs. This provides important constraints for accretion disk models. It also provides support to the idea that BAL quasars, at least their radio-loud subclass, represent an early evolutionary stage of quasars.

  17. Evaluation of a seasonal storage system of solar energy for house heating using different absorption couples

    Liu Hui, E-mail: hui.liu@univ-savoie.f [LOCIE, CNRS UMR 5271-Universite de Savoie, Polytech' Savoie, Campus Scientifique, Savoie Technolac, 73376 Le Bourget-Du-Lac Cedex (France); Edem, N' Tsoukpoe K., E-mail: Kokouvi-Edem.N-Tsoukpoe@univ-savoie.f [LOCIE, CNRS UMR 5271-Universite de Savoie, Polytech' Savoie, Campus Scientifique, Savoie Technolac, 73376 Le Bourget-Du-Lac Cedex (France); Nolwenn, Le Pierres, E-mail: nolwenn.le-pierres@univ-savoie.f [LOCIE, CNRS UMR 5271-Universite de Savoie, Polytech' Savoie, Campus Scientifique, Savoie Technolac, 73376 Le Bourget-Du-Lac Cedex (France); Luo Lingai, E-mail: lingai.luo@univ-savoie.f [LOCIE, CNRS UMR 5271-Universite de Savoie, Polytech' Savoie, Campus Scientifique, Savoie Technolac, 73376 Le Bourget-Du-Lac Cedex (France)

    2011-06-15

    Research highlights: {yields} An absorption system for long-term energy storage for house heating is presented. {yields} The storage capacity and efficiency of seven absorption couples are studied. {yields} The influence of temperature of absorption, evaporation and storage is evaluated. {yields} The appearance of crystals in the storage tank increases the storage capacity. -- Abstract: In this paper, an innovative concept is presented for a long-term energy storage system for house heating, using the absorption process. The solar energy is stored during summer through desorption and the heat is released during winter through absorption. The originality of this concept is to allow the solution to reach the crystallization point, which is usually avoided in the absorption refrigeration machines. The storage capacity and efficiency of seven absorption couples, CaCl{sub 2}/H{sub 2}O, Glycerin/H{sub 2}O, KOH/H{sub 2}O, LiBr/H{sub 2}O, LiCl/H{sub 2}O, NaOH/H{sub 2}O and H{sub 2}O/NH{sub 3}, as a function of the temperature of absorption, temperature of evaporation, temperature of the solution before absorption and the presence of crystals in the storage tank have been studied in this paper. The appearance of crystals increases the storage capacity. The storage capacity increases with the temperature of evaporation and the temperature of the solution before absorption but decreases with the temperature of absorption.

  18. Evaluation of a seasonal storage system of solar energy for house heating using different absorption couples

    Research highlights: → An absorption system for long-term energy storage for house heating is presented. → The storage capacity and efficiency of seven absorption couples are studied. → The influence of temperature of absorption, evaporation and storage is evaluated. → The appearance of crystals in the storage tank increases the storage capacity. -- Abstract: In this paper, an innovative concept is presented for a long-term energy storage system for house heating, using the absorption process. The solar energy is stored during summer through desorption and the heat is released during winter through absorption. The originality of this concept is to allow the solution to reach the crystallization point, which is usually avoided in the absorption refrigeration machines. The storage capacity and efficiency of seven absorption couples, CaCl2/H2O, Glycerin/H2O, KOH/H2O, LiBr/H2O, LiCl/H2O, NaOH/H2O and H2O/NH3, as a function of the temperature of absorption, temperature of evaporation, temperature of the solution before absorption and the presence of crystals in the storage tank have been studied in this paper. The appearance of crystals increases the storage capacity. The storage capacity increases with the temperature of evaporation and the temperature of the solution before absorption but decreases with the temperature of absorption.

  19. LED-Based High-Voltage Lines Warning System

    Eldar MUSA

    2013-04-01

    Full Text Available LED-based system, running with the current of high-voltage lines and converting the current flowing through the line into the light by using a toroid transformer, has been developed. The transformer’s primary winding is constituted by the high voltage power line. Toroidal core consists of two equal parts and the secondary windings are evenly placed on these two parts. The system is mounted on the high-voltage lines as a clamp. The secondary winding ends are connected in series by the connector on the clamp. LEDs are supplied by the voltage at the ends of secondary. Current flowing through highvoltage transmission lines is converted to voltage by the toroidal transformer and the light emitting LEDs are supplied with this voltage. The theory of the conversion of the current flowing through the line into the light is given. The system, running with the current of the line and converting the current into the light, has been developed. System has many application areas such as warning high voltage lines (warning winches to not hinder the high-voltage lines when working under the lines, warning planes to not touch the high-voltage lines, remote measurement of high-voltage line currents, and local illumination of the line area

  20. Flow injection determination of copper in mussels by flame atomic absorption spectrometry after on-line continuous ultrasound-assisted extraction

    Moreno-Cid, A.; Yebra, M. C.

    2002-05-01

    Copper was extracted on-line from solid mussel samples by a simple and rapid continuous ultrasound-assisted extraction system (CUES). The CUES is connected to a flow injection manifold, which permits the on-line flame atomic absorption spectrometric determination of copper. The manifold is simple and the copper signal was obtained for a volume of 250 μl of acid leachate injected into an ultrapure water carrier stream. An experimental design was used for the optimization of the continuous leaching procedure. Compared to off-line ultrasonic-assisted extraction methods, sonication time is reduced by factors of 6-12, the leaching takes place at room temperature (20 °C), and the analysis time is reduced because centrifugation was not necessary to separate the liquid phase. The method allowed a total sampling frequency of 11 samples h -1, with a relative standard deviation for the complete procedure of 2.7% (for a sample containing 2.0 μg g -1 copper (wet mass, n=11). The limit of detection was 0.06 μg g -1 (wet mass) for 30 mg of sample. The analytical procedure was verified for a reference standard material (TORT-1). The analytical procedure was applied to mussel samples from Galicia (Spain).

  1. A Bayesian Method For Finding Galaxies That Cause Quasar Absorption Lines

    Shoemaker, Emileigh Suzanne; Laubner, David Andrew; Scott, Jennifer E.

    2016-01-01

    We present a study of candidate absorber-galaxy pairs for 39 low redshift quasar sightlines (0.06 Digital Sky Survey (SDSS). We downloaded the COS linelists for these quasar spectra from MAST and queried the SDSS DR12 database for photometric data on all galaxies within 1 Mpc of each of these quasar lines of sight. We calculated photometric redshifts for all the SDSS galaxies using the Bayesian Photometric Redshift code. We used all these absorber and galaxy data as input into an absorber-galaxy matching code which also employs a Bayesian scheme, along with known statistics of the intergalactic medium and circumgalactic media of galaxies, for finding the most probable galaxy match for each absorber. We compare our candidate absorber-galaxy matches to existing studies in the literature and explore trends in the absorber and galaxy properties among the matched and non-matched populations. This method of matching absorbers and galaxies can be used to find targets for follow up spectroscopic studies.

  2. Speciation of four selenium compounds using high performance liquid chromatography with on-line detection by inductively coupled plasma mass spectrometry or flame atomic absorption spectrometry

    Pedersen, Gitte Alsing; Larsen, Erik Huusfeldt

    1997-01-01

    with an aqueous solution of 6 mmol L-1 of salicylate ion at pH 8.5 as the mobile phase which allowed the isocratic separation of the four selenium analytes within 8 minutes. The separated selenium species were detected on-line by flame atomic absorption spectrometry (FAAS) or inductively coupled plasma mass...... spectrometry (ICP-MS). The signal-to-noise ratio of the FAAS detector was optimized using a hydrogen-argon entrained-air flame and a slotted-tube atom trap (STAT) in the flame. The limit of detection (3 sigma) achieved by the HPLC-FAAS system was 1 mg L-1 of selenium (100 mu L injections) for each of the four...

  3. Development of an x-ray beam line at the NSLS for studies in materials science using x-ray absorption spectroscopy

    At the time of the submission of the original proposal more than 7 years ago, the X-11 PRT had set as a goal to develop one of the leading and most comprehensive x-ray absorption beam lines in the world. By any measure we have been successful. As is well documented in previous annual progress report and in the NSLS annual reports, our PRT has been extremely productive in a wide range of topics in materials science, solid state physics, chemistry and biology. Well over 100 papers have been published acknowledging the support of this contract and this continues at a rate of about 30 papers per year and about 20 invited presentations per year. Significant in this report are major studies in high Tc compounds, advances in interface studies, new results in premelting phenomena, several pioneering studies in application of XAS to electrochemistry and significant progress in our understanding of the structure of amorphous chalcogenide systems and their photostructural changes

  4. A new active absorption system and its performance to linear and non-linear waves

    Andersen, Thomas Lykke; Clavero, M.; Frigaard, Peter Bak; Losada, M.; Puyol, J. I.

    Highlights •An active absorption system for wavemakers has been developed. •The theory for flush mounted gauges has been extended to cover also small gaps. •The new system has been validated in a wave flume with wavemakers in both ends. •A generation and absorption procedure for highly non-linear...

  5. Monitoring System of Power Line Icing Based on GPRS

    Wancheng, Xie

    GPRS-based power line monitoring system for ice. The system is based on the images to monitor the power line monitoring device for ice. System through the use of simplified Sobel algorithm and Hough transform to image edge detection, with DSP high-speed computing performance and optimization of DSP code, and realized the power line ice thickness of the terminal identification and automatic alarm function; using the terminal identification means, is intelligent Monitoring of a new attempt.

  6. The Absorption Spectrum of High-Density Stellar Ejecta in the Line-of-Sight to Eta Carinae

    Gull, T R; Bruhweiler, F C; Nielsen, K E; Verner, E; Danks, A

    2004-01-01

    Using the high dispersion NUV mode of the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST) to observe Eta Carinae, we have resolved and identified over 500 sharp, circumstellar absorption lines of iron-group singly-ionized and neutral elements with ~20 velocity components ranging from -146 km/s to -585 km/s. These lines are from transitions originating from ground and metastable levels as high as 40,000 cm-1 above ground. The absorbing material is located either in dense inhomogeneities in the stellar wind, the warm circumstellar gas immediately in the vicinity of Eta Carinae, or within the cooler foreground lobe of the Homunculus. We have used classical curve-of-growth analysis to derive atomic level populations for FeII at -146 km/s and for TiII at -513 km/s. These populations, plus photoionization and statistical equilibrium modeling, provide electron temperatures, Te, densities, n, and constraints on distances from the stellar source, r. For the -146 km/s component, we d...

  7. Solar-driven ejector-absorption cooling system

    The usage possibility of ejector-absorption cooling systems (EACSs) in Turkey using meteorological data has been investigated. This study also determines whether or not the required heat for the generator of an EACS can be obtained from solar energy in Turkey. There are two important reasons for the usage of EACSs in Turkey. One of them is that the production and use of the CFCs and HCFCs will be phased out a few years according to the Montreal Protocol, signed in 1987. The other is that Turkey is located between 36 deg. and 42 deg. N latitudes and has a typical Mediterranean climate. Therefore, Turkey has a high solar-energy potential, and the yearly average solar-radiation and the total yearly radiation period are 3.6 kW h/m2 day and ∼2610 h, respectively. Sixteen cities (Ordu, Tekirdag, Sakarya, Corum, Erzincan, Bursa, Balikesir, Afyon, Bingoel, Burdur, Konya, Nigde, Adiyaman, Hakkari, Anamur, Finike) were selected in Turkey for which the radiation data and sunshine-duration information have been collected since 2000. The required optimum collector-surface area was identified by using the meteorological data for maximum coefficient-of-performance (COPmax) conditions of the EACS operated with aqua-ammonia. In addition, the required minimum energy for the auxiliary heater was also calculated so that the system can be used throughout the year. It is shown that the heat-gain factor (HGF) varies in the range from 1.34 to 2.85 for all the seasons in the selected cities. The maximum HGF is 2.85 for Finike. According to the results obtained in this study, for 8 → 9 months (March-October), it is sufficient to have a collector surface-area of 4 m2 with high-performance refrigeration all over of Turkey. This study will provide guidance for the efficient utilisation of renewable energy sources in Turkey, which is heavily dependent upon imported energy sources, i.e. natural gas

  8. Properties of multilayer optical systems formed by layers with small absorption in inclined falling of radiation

    Karyaev, Konstantin V.; Zhoga, Eugene V.; Putilin, Eduard S.

    2000-10-01

    Multilayer dielectric systems find wide employment in different fields of science and engineering. Dielectric systems, formed by layers with small absorption, attract particular interest. Value of absorption, as a rule, depends on structure of the system (order and optical thickness of layers), angle of incidence and wavelength of radiation. Experiment shows that there are peaks of absorption on certain angles of incidence and wavelength, but behavior of absorption wasn't studied well. Model of a system, formed by isotropic layers settled on semiinfinite substate proved to be a good approximation for many of real optical systems. We studied pecularities in spectral dependencies of reflection, transmission and absorption coefficients in dependance on the angle of incidence and wavelength of falling radiation with flat wave front. Problem was solved on the basis of Maxwell equations and corresponding boundary conditions.

  9. X-RAYS FROM A RADIO-LOUD COMPACT BROAD ABSORPTION LINE QUASAR 1045+352 AND THE NATURE OF OUTFLOWS IN RADIO-LOUD BROAD ABSORPTION LINE QUASARS

    We present new results on X-ray properties of radio-loud broad absorption line (BAL) quasars and focus on broadband spectral properties of a high-ionization BAL (HiBAL) compact steep spectrum (CSS) radio-loud quasar 1045+352. This HiBAL quasar has a very complex radio morphology indicating either strong interactions between a radio jet and the surrounding interstellar medium or a possible re-start of the jet activity. We detected 1045+352 quasar in a short 5 ksec Chandra ACIS-S observation. We applied theoretical models to explain spectral energy distribution of 1045+352 and argue that non-thermal, inverse-Compton (IC) emission from the innermost parts of the radio jet can account for a large fraction of the observed X-ray emission. In our analysis, we also consider a scenario in which the observed X-ray emission from radio-loud BAL quasars can be a sum of IC jet X-ray emission and optically thin corona X-ray emission. We compiled a sample of radio-loud BAL quasars that were observed in X-rays to date and report no correlation between their X-ray and radio luminosity. However, the radio-loud BAL quasars show a large range of X-ray luminosities and absorption columns. This is consistent with the results obtained earlier for radio-quiet BAL quasars and may indicate an orientation effect in BAL quasars or more complex dependence between X-ray emission, radio emission, and an orientation based on the radio morphology.

  10. The gaseous extent of galaxies and the origin of Lyman alpha absorption systems; 4, Lyman$\\alpha$ absorbers arising in a galaxy group

    Ortiz-Gill, A; Webb, J K; Barcons, X; Fernández-Soto, A

    1999-01-01

    We present new GHRS observations of Lyman alpha absorption lines associated with a group of galaxies towards the QSO 1545+2101. We have identified eight distinct Lyman alpha absorption features in the spectrum of QSO 1545+2101 at a mean redshift of z=0.2648 with a velocity dispersion of 163 km/s. A group of galaxies is detected in the vicinity of this QSO at a mean redshift of z=0.2645 and velocity dispersion 239 km/s. The identification of discrete absorption systems indicates that they arise in clouds of neutral hydrogen rather than in a diffuse intragroup medium. Our analysis suggests that the Lyman alpha absorption lines are associated with individual galaxies in the group, although a one-to-one relationship between absorbers and galaxies is difficult to establish in such a dense environment.

  11. System Requirements for On-Line and Batch Retrieval.

    American Society for Information Science, Washington, DC. Special Interest Group on Computerized Retrieval Services.

    Three papers on system requirements for on-line and batch retrieval presented at the American Society for Information Science (ASIS) annual meeting are included here. At G.D. Searle, data for records related to pharmacology screening are used in a batch system, and an on-line system is used to search information on mutagenic, carcinogenic, and…

  12. On-Line Administrative Information Systems: A Case Study.

    Sire, Paul W.

    A case study approach is used to document the on-line information system developed by the Office of Management Information and Computing at the University of Vermont. Stanford University's Project INFO On-Line Administration Information System, OASIS, was chosen as a model. The administrative system is one of two on campus, the other designed for…

  13. In-situ rehabilitation cleans, lines, and renews pipe systems

    This article discusses how, in the past five years, developments in coating and lining material technology have found their way into pipe line application and have yielded successful results. The thick film, high solids material often used to repair tanks, vessels and offshore structures has now been adapted for existing pipe lines. One of the most promising of these systems in successful service is an epoxy, high solids (95%) material originally developed for nuclear service as a lining for reactor containment vessels

  14. The gaseous extent of galaxies and the origin of Lyman alpha absorption systems. IV: Lyman alpha absorbers arising in a galaxy group

    Ortiz-Gil, A.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.; Fernandez-Soto, A.

    1999-01-01

    We present new GHRS observations of Lyman alpha absorption lines associated with a group of galaxies towards the QSO 1545+2101. We have identified eight distinct Lyman alpha absorption features in the spectrum of QSO 1545+2101 at a mean redshift of z=0.2648 with a velocity dispersion of 163 km/s. A group of galaxies is detected in the vicinity of this QSO at a mean redshift of z=0.2645 and velocity dispersion 239 km/s. The identification of discrete absorption systems indicates that they aris...

  15. Bioavailability and absorption kinetics of nicotine following application of a transdermal system.

    Gupta, S.K.; Benowitz, N L; Jacob, P.; Rolf, C N; Gorsline, J

    1993-01-01

    1. The absolute bioavailability and absorption kinetics of nicotine were investigated in 13 healthy adult male smokers following single and multiple applications of a nicotine transdermal system (NTS), designed to release nicotine at an approximate rate of 1.5 mg h-1 over 24 h. The absorption of nicotine from the single NTS application was calculated with reference to a simultaneous intravenous infusion (i.v.) of deuterium-labelled nicotine. 2. The mean input time (MIT) and mean absorption ti...

  16. Evidence for ultra-fast outflows in radio-quiet AGNs: II - detailed photo-ionization modeling of Fe K-shell absorption lines

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G.G.C.; Braito, V.; Dadina, M.

    2011-01-01

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet AGNs. In the previous paper of this series we defined UFOs as those absorbers with an outflow velocity higher than 10,000km/s and assessed the statistical significance of the associated blueshifted FeK absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. In the present paper we report a detailed curve of growth analysis and direct...

  17. An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-Mass X-Ray Binary 1A 1744-361

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2012-01-01

    We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu 103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source

  18. Flow injection on-line dilution for flame atomic absorption spectrometry by micro-sample introduction and dispersion using syringe pumps

    A robust flow injection (FI) on-line dilution system based on micro-sample introduction was developed for flame atomic absorption spectrometry (FAAS). Two computer programmed and stepper-motor driven syringe pumps were used for the precise and reproducible sample metering in micro-liters and carrier delivery. Factors, which might influence the performance of the system, such as sample matrix and carryover, were investigated. No inferior effects were observed with various matrices including 10% glycerol. Sample carryover effects were less than 0.4%, tested by analyzing a blank and a sample alternately. Dilution factors were decided and keyed in manually. The system was calibrated using a set of concentrated standard solutions for a given dilution factor. At a sampling frequency of 60 h-1, precisions were better than 2% R.S.D. (n=40) for dilution factors of 10-2000. The long-term stability of the system was examined by continuously running the system for a whole working day, and a precision of 2.6% R.S.D. (n=345) was obtained at a dilution factor of 1000. The system was verified by analyzing a standard copper alloy with a certified concentration of 57.4% Cu, resulting in a measurement solution with 574 mg l-1 Cu

  19. Development of an x-ray beam line at the NSLS for studies in materials science using x-ray absorption spectroscopy: Annual progress report

    Although only in operation since May, 1985, the X-11 participation research team (PRT) at the NSLS has already demonstrated that it is one of the leading centers of x-ray absorption spectroscopy (XAS). During this time, results have been obtained and programs initiated in a number of areas, for example: interfaces, including deposited metal-metal and metal-semiconductor systems, multilayers and ion implanted layers; electrochemical systems, including Pt electrode fuel cells, Ni oxide battery electrodes, conducting polymers, passivation and corrosion; catalysts, including highly-dispersed supported metal catalysts and zeolite systems; quasi-crystals, heavy fermion systems, uranium and neptunium compounds, rare gas clusters, disordered metals and semiconductors, ferroelectric transition; and, biological systems and related models, including synthetic porphyrins and a number of metalloproteins. In concert with these scientific results have been a number of developments involving the technique itself. These include implementation of unique optical systems on both the A and B lines for optical performance over their designed energy ranges, advances in experimental capability, particular in glancing angle studies, optimization of ion chambers for surface studies, the improvement of electron yield detectors, and improved software for data acquisition and analysis. This report emphasizes some of the research highlights and significant developments of our PRT which occurred during the past year. A detailed bibliography of papers and talks resulting from work done at our beamline and the progress reports for our PRT which were in the 1985 NSLS Annual Report are appended

  20. Influence of the multiple scattering of relativistic electrons on the line width of backward Parametric X-ray Radiation in the absence of photo absorption

    Tabrizi, Mehdi

    2015-01-01

    The multiple scattering effect on the line width of backward Parametric X-ray Radiation (PXR) in the extremely Bragg geometry, produced by low energy relativistic electrons traversing a single crystal, is discussed. It is shown that there exist conditions, when the influence of photo absorption on the line width can be neglected, and the only multiple scattering process of relativistic electrons in crystal leads to the broadening of backward PXR lines. Based on the obtained theoretical results, the line width broadening of backward PXR, caused by the multiple scattering of 30 MeV and 50 MeV relativistic electrons in a Si crystal of varying thicknesses, is numerically obtained.

  1. Chandra view of the warm-hot intergalactic medium toward 1ES 1553+113: Absorption-line detections and identifications. I

    F. Nicastro; Barcons, Xavier; Paerels, F. B. S.

    2013-01-01

    We present the first results from our pilot 500 ks Chandra Low Energy Transmission Grating Large Program observation of the soft X-ray brightest source in the z ≳ 0.4 sky, the blazar 1ES 1553+113, aimed to secure the first uncontroversial detections of the missing baryons in the X-rays. We identify a total of 11 possible absorption lines, with single-line statistical significances between 2.2σ and 4.1σ. Six of these lines are detected at high single-line statistical significance (3.6 ≤ σ ≤ 4....

  2. On-line solid-phase separation/preconcentration for the determination of copper in urine by flame atomic absorption spectrometry

    A new on-line separation/preconcentration system was developed for the determination of Cu(II) ions by flame atomic absorption spectrometry in urine samples. A newly synthesized chelating resin, by anchoring eriochrome blue black R reagent to Amberlite XAD-16 resin, was used as a packing material for the selective separation/preconcentration of Cu(II) ions. The influence of the parameters on the determination of Cu(II) ions such as pH of sample solution, amount of the resin, eluent type, interfering ions and flow variables was studied. The detection limit of the method was 1.0 μg L−1 while precision was 2.3% (n = 15) at 50 μg L−1 Cu(II) level. The adsorption capacity of the resin was 217 μg g−1 Cu(II). The accuracy of the method was proven using TMDA-64 standard lake water and synthetic urine sample. The developed method has been applied successfully to the determination of copper in urine with satisfactory results. - Highlights: • The method was applied to the urine samples taken from Wilson’s patients. • The on-line determination of copper and satisfactory results were obtained. • All processes are made automatically by the system itself in the proposed method

  3. STAR CLUSTERS IN M31. IV. A COMPARATIVE ANALYSIS OF ABSORPTION LINE INDICES IN OLD M31 AND MILKY WAY CLUSTERS

    We present absorption line indices measured in the integrated spectra of globular clusters both from the Galaxy and from M31. Our samples include 41 Galactic globular clusters, and more than 300 clusters in M31. The conversion of instrumental equivalent widths into the Lick system is described, and zero-point uncertainties are provided. Comparison of line indices of old M31 clusters and Galactic globular clusters suggests an absence of important differences in chemical composition between the two cluster systems. In particular, CN indices in the spectra of M31 and Galactic clusters are essentially consistent with each other, in disagreement with several previous works. We reanalyze some of the previous data, and conclude that reported CN differences between M31 and Galactic clusters were mostly due to data calibration uncertainties. Our data support the conclusion that the chemical compositions of Milky Way and M31 globular clusters are not substantially different, and that there is no need to resort to enhanced nitrogen abundances to account for the optical spectra of M31 globular clusters.

  4. Optical and mechanical design of the extended x-ray absorption fine structure (EXAFS) beam-line at Indus-II synchrotron source

    An extended x-ray absorption fine structure (EXAFS) beam line for x-ray absorption studies using energy dispersive geometry and position sensitive detector is being designed for the INDUS-II Synchrotron source. The beam line would be used for doing x-ray absorption experiments involving measurements of fme structures above the absorption edge of different species of atoms in a material The results of the above experiments would lead to the determination of different important structural parameters of materials viz.. inter-atomic distance. co-ordination number, degree of disorder and radial distribution function etc. The optical design of the beam line has been completed based on the working principle that a single crystal bent in the shape of an ellipse by a crystal bender would act as a dispersing as well as focusing element. The mechanical design of the beam line including the crystal bender has also been completed and discussed here. Calculations have been done to detennine the temperature profile on the different components of the beam line under exposure to synchrotron radiation and proper cooling channels have been designed to bring down the heat load on the components. (author)

  5. The 13CH4 absorption spectrum in the Icosad range (6600-7692 cm-1) at 80 K and 296 K: Empirical line lists and temperature dependence

    Campargue, A.; Béguier, S.; Zbiri, Y.; Mondelain, D.; Kassi, S.; Karlovets, E. V.; Nikitin, A. V.; Rey, M.; Starikova, E. N.; Tyuterev, Vl. G.

    2016-08-01

    The 13CH4 absorption spectrum has been recorded at 296 K and 80 K in the Icosad range between 6600 and 7700 cm-1. The achieved noise equivalent absorption of the spectra recorded by differential absorption spectroscopy (DAS) is about αmin ≈ 1.5 × 10-7 cm-1. Two empirical line lists were constructed including 17,792 and 24,139 lines at 80 K and 296 K, respectively. For comparison, the HITRAN database provides only 1040 13CH4 lines in the region determined from methane spectra with natural isotopic abundance. Empirical values of the lower state energy level, Eemp, were systematically derived from the intensity ratios of the lines measured at 80 K and 296 K. Overall 10,792 Eemp values were determined providing accurate temperature dependence for most of the 13CH4 absorption in the region (93% and 82% at 80 K and 296 K, respectively). The quality of the derived empirical values of the lower state rotational quantum number, Jemp, is illustrated by their clear propensity to be close to an integer. A good agreement is achieved between our small Jemp values, with previous accurate determinations obtained by applying the 2T method to jet and 80 K spectra. The line lists at 296 K and 80 K which are provided as Supplementary material will be used for future rovibrational assignments based on accurate variational calculations.

  6. Unveiling the intrinsic X-ray properties of broad absorption line quasars with a relatively unbiased sample

    There is growing evidence of a higher intrinsic fraction of broad absorption line quasars (BALQSOs) than that obtained in optical surveys, on which most previous X-ray studies of BALQSOs have focused. Here we present Chandra observations of 18 BALQSOs at z ∼ 2, selected from a near-infrared (Two Micron All Sky Survey) sample, where the BALQSO fraction is likely to be close to the intrinsic fraction. We measure photon indices using the stacked spectra of the optically faint (i – Ks ≥ 2.3 mag) and optically bright (i – Ks < 2.3 mag) samples to be Γ ≅ 1.5-2.1. We constrain their intrinsic column density by modeling the X-ray fractional hardness ratio, finding a mean column density of 3.5 × 1022 cm–2 assuming neutral absorption. We incorporate Sloan Digital Sky Survey optical measurements (rest frame UV) to study the broadband spectral index between the X-ray and UV bands, and compare this to a large sample of normal quasars. We estimate that the optically faint BALQSOs are X-ray weaker than the optically bright ones, and the entire sample of BALQSOs are intrinsically X-ray weak when compared to normal active galactic nuclei (AGNs). Correcting for magnification of X-ray emission via gravitational lensing by the central black hole viewed at large inclination angles makes these BALQSOs even more intrinsically X-ray weak. Finally, we estimate AGN kinetic feedback efficiencies of a few percent for an X-ray wind of 0.3c in high-ionization BALQSOs. Combined with energy carried by low-ionization BALQSOs and UV winds, the total kinetic energy in BALQSOs can be sufficient to provide AGN kinetic feedback required to explain the co-evolution between black holes and host galaxies.

  7. Relationship Network Analysis of Manufacturing System Limited by Business Lines

    Chen, Guorong; Yan, Ping; SHI Jinliang; DENG Juli

    2012-01-01

    It is a common problem of manufacturing enterprise limited by business line, which optimized its resources allocation to increase productivity, but now the researches are very weak in relationship mapping and network analysis method in the world. Aimed to the demands, proposed a resource allocation method limited by business line of manufacturing system based on the relational mapping of production system, manufacturing model of hierarchical network based on business line and node degree...

  8. Weak hard X-ray emission from broad absorption line quasars: evidence for intrinsic X-ray weakness

    We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z < 1.3. However, their rest-frame ≈2 keV luminosities are 14 to >330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with ≲ 45 counts in the 3-24 keV band, and the other three are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (Γeff ≈ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X-ray weakness observed by NuSTAR for this and the pilot samples selected with <10 keV weakness also suggests that the X-ray weakness is intrinsic in at least some of the targets. We conclude that the NuSTAR observations have likely discovered a significant population (≳ 33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.

  9. Weak hard X-ray emission from broad absorption line quasars: evidence for intrinsic X-ray weakness

    Luo, B.; Brandt, W. N.; Scott, A. E. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Alexander, D. M.; Gandhi, P. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Teng, S. H. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Arévalo, P.; Bauer, F. E. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Comastri, A. [INAF—Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Harrison, F. A. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Koss, M. [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Ogle, P. [IPAC, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125 (United States); Puccetti, S. [ASDC—ASI, Via del Politecnico, I-00133 Roma (Italy); Saez, C. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); and others

    2014-10-10

    We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z < 1.3. However, their rest-frame ≈2 keV luminosities are 14 to >330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with ≲ 45 counts in the 3-24 keV band, and the other three are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (Γ{sub eff} ≈ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X-ray weakness observed by NuSTAR for this and the pilot samples selected with <10 keV weakness also suggests that the X-ray weakness is intrinsic in at least some of the targets. We conclude that the NuSTAR observations have likely discovered a significant population (≳ 33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.

  10. Absorption Changes Induced by Off-Resonance Driving a Degenerate Two-Level System

    The alteration of atomic absorption via quantum coherence is observed in the degenerate two-level atomic system. It is shown that when the detuning of coupling field equals to that of probe light, i.e. two-photon resonance, the reduction of atomic absorption via electromagnetically induced transparency occurs. However, when we tune the coupling field to two-photon off-resonance, the enhancement of absorption is obtained for the probe field. The influences of one-photon detuning and intensity of coupling field on absorption are also experimentally demonstrated. (fundamental areas of phenomenology (including applications))

  11. CHIRAL MULTIPHOTON ABSORPTION AND INVERSE SKIN EFFECT IN WLAN SYSTEMS

    Héctor Torres Silva; Mario Zamorano Lucero

    2005-01-01

    A model formed by chiral bioplasma with a set of macromolecules of DNA, which represents the human head inner structure, makes possible to analyze its behavior, when it is radiated by a microwave electromagnetic field from cellular phones and WLAN's at frequencies of 2.4 and 5.2 GHz is presented. The finite difference time domain, FDTD, numeric technique is used under multiphoton regime deduced from Maxwell equations. The numerical results of the Specific Absorption Rate, SAR, show the SAR be...

  12. Integrating Robot Task Planning into Off-Line Programming Systems

    Sun, Hongyan; Kroszynski, Uri

    1988-01-01

    The addition of robot task planning in off-line programming systems aims at improving the capability of current state-of-the-art commercially available off-line programming systems, by integrating modeling, task planning, programming and simulation together under one platform. This article proposes...

  13. Integration of process and solvent design towards a novel generation of CO2 absorption capture systems

    Oyarzun, B.A.; Bardow, A.; Gross, J.

    2011-01-01

    A method for the integrated process and solvent design of absorption separation systems is proposed in this work. The method is employed here to improve the energetic performance of a pre-combustion CO2 absorption capture process by simultaneous optimization of process and solvent variables. In the

  14. The Origin of a Chemically Enriched lya Absorption System at z=0.167

    Chen, H W; Chen, Hsiao-Wen; Prochaska, Jason X.

    2000-01-01

    We present the first detailed analysis of the chemical abundances, ionization state, and origin of a partial Lyman limit system (N(\\hI) ~ 10^{16} \\cmjj) at low redshift (z=0.167 towards PKS0405-1219). Two galaxies at ~ 70 h^{-1} kpc projected distance to the QSO have been identified at the absorber redshift. We analyze an echelle spectrum of the QSO obtained with the Space Telescope Imaging Spectrograph and find that this absorption system exhibits associated lines produced by C^+, N^+, O^0, Si^+, Si^{++}, Si^{+3}, Fe^+, and Fe^{++}, and most interestingly, O^{+5} and N^{+4}. The results of our analysis show that the partial Lyman limit system traced by various ions is likely to be embedded in a collisionally ionized \\ovi gas of larger spatial extent. Furthermore, the partial Lyman limit system appears to have a metallicity of {\\em at least} 1/10 solar and most likely solar or super solar despite the fact that no luminous galaxies are seen within a projected distance \\rho = 60 h^{-1} kpc to the QSO. Finally, ...

  15. Simulation Based Optimization for World Line Card Production System

    Sinan APAK

    2012-07-01

    Full Text Available Simulation based decision support system is one of the commonly used tool to examine complex production systems. The simulation approach provides process modules which can be adjusted with certain parameters by using data relatively easily obtainable in production process. World Line Card production system simulation is developed to evaluate the optimality of existing production line via using discrete event simulation model with variaty of alternative proposals. The current production system is analysed by a simulation model emphasizing the bottlenecks and the poorly utilized production line. Our analysis identified some improvements and efficient solutions for the existing system.

  16. LINES

    Minas Bakalchev

    2015-10-01

    Full Text Available The perception of elements in a system often creates their interdependence, interconditionality, and suppression. The lines from a basic geometrical element have become the model of a reductive world based on isolation according to certain criteria such as function, structure, and social organization. Their traces are experienced in the contemporary world as fragments or ruins of a system of domination of an assumed hierarchical unity. How can one release oneself from such dependence or determinism? How can the lines become less “systematic” and forms more autonomous, and less reductive? How is a form released from modernistic determinism on the new controversial ground? How can these elements or forms of representation become forms of action in the present complex world? In this paper, the meaning of lines through the ideas of Le Corbusier, Leonidov, Picasso, and Hitchcock is presented. Spatial research was made through a series of examples arising from the projects of the architectural studio “Residential Transformations”, which was a backbone for mapping the possibilities ranging from playfulness to exactness, as tactics of transformation in the different contexts of the contemporary world.

  17. The absorption spectrum of 13CH4 in the region of the 2ν3 band at 1.66 µm: Empirical line lists and temperature dependence

    The absorption spectrum of 13CH4 has been recorded at 296 K and 80 K by differential absorption spectroscopy (DAS) in the high energy part of the tetradecad (5853–6201 cm−1) dominated by the 2ν3 band near 5988 cm−1. The achieved noise equivalent absorption of the spectra (αmin≈1×10−7 cm−1) allowed us to double the number of 13CH4 lines previously measured in the region (our lists include about 7200 and 3700 lines at 296 and 80 K, respectively). Empirical values of the lower state energy level, Eemp, were systematically derived from the intensity ratios of the lines measured at 80 K and 296 K. Overall 2782 Eemp values were determined extending significantly the previous set of about 1200 Eemp values available in the literature. The corresponding empirical values of the rotational quantum number, Jemp, show a clear propensity to be close to an integer, illustrating the validity of the method. The line lists at 296 K and 80 K, provided as Supplementary material, are discussed in relation with line lists and rovibrational assignments available in the literature. - Highlights: • Spectra of “pure” 13CH4 recorded in the 2ν3 region at 80 K and 296 K. • Empirical list of 7207 and 3717 lines are constructed at 296 and 80 K, respectively. • The 2-Temperature method is applied. • 2782 Empirical lower state energy values are determined

  18. Nustar Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231

    Teng, Stacy H.; Brandt. W. N.; Harrison, F. A.; Luo, B.; Alexander, D. M.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Fabian, A. C.; Farrah, D.; Fiore, F.; Gandhi, P.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R. C.; Madsen, K. K.; Ptak, A. F.; Rigby, Jane Rebecca; Risaliti, G.; Saz, C.; Stern, D.; Veilleux, S.; Walton, D. J.; Wik, D. R.; Zhang, W. W.

    2014-01-01

    We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin N(sub H) approx. 1.2(sup +0.3) sub-0.3) x 10(exp 23) / sq cm) column. The intrinsic X-ray luminosity L(sub 0.5-30 Kev) approx. 1.0 x 10(exp 43) erg /s) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is approx. 0.03% compared to the typical values of 2-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope alpha(sub 0X) approx. -1.7. It is a local example of a low-ionization broad absorption line (LoBAL) quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

  19. Stochastic Absorption of the Light of Background Sources due to Intergalactic Neutral Hydrogen I. Testing different line-number evolution models via the cosmic flux decrement

    Tepper-Garc{\\'\\i}a, Thorsten

    2007-01-01

    We test the accuracy of different models of the attenuation of light due to intergalactic neutral hydrogen by comparing their predictions of the evolution of the mean cosmic flux decrement D_A to its measurements based on observations. To this end, we use data available in the literature and our own measurements of D_A for 25 QSOs in the redshift range 2.64 < z < 5.41 taken from the SDSS Data Release 5. In order to perform the measurements of D_A, we fit a power-law to the continuum redward of the Lyman Alpha emission line, and extrapolate this fit to region blueward of it, where the flux is severely affected by absorption due to intervening HI absorbers. We compute, using numerical simulations, the redshift evolution of the mean flux depression due to the presence of Lyman Alpha Forest absorbers and Lyman limit systems randomly distributed along the line-of-sight, and compute its intrinsic scatter at the 1-, 2-, and 3$\\sigma$ level due to fluctuations in the absorber properties (column density, Doppler...

  20. Evidence for ultra-fast outflows in radio-quiet AGNs: I - detection and statistical incidence of Fe K-shell absorption lines

    Tombesi, F; Reeves, J N; Palumbo, G G C; Yaqoob, T; Braito, V; Dadina, M

    2010-01-01

    We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies E>7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3x10^-8, and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability <10^-7. We identify the lines as Fe XXV and Fe XXVI K-shell resonant absorption. They are systematically blue-shifted, with a velocity distribution ranging from zero up to 0.3c, with a peak and mean value at 0.1c. We detect variability of the lines on both EWs and blue-shifted velocities among different observations even on time-scales as short as a few days, possibly suggesting somewhat compact absorbers. Moreover, we find no significant correlation between the cosmological red-sh...

  1. Precise limits on cosmological variability of the fine-structure constant with zinc and chromium quasar absorption lines

    Murphy, Michael T; Prochaska, J Xavier

    2016-01-01

    The strongest transitions of Zn and CrII are the most sensitive to relative variations in the fine-structure constant ($\\Delta\\alpha/\\alpha$) among the transitions commonly observed in quasar absorption spectra. They also lie within just 40 \\AA\\ of each other (rest frame), so they are resistant to the main systematic error affecting most previous measurements of $\\Delta\\alpha/\\alpha$: long-range distortions of the wavelength calibration. While Zn and CrII absorption is normally very weak in quasar spectra, we obtained high signal-to-noise, high-resolution echelle spectra from the Keck and Very Large Telescopes of 9 rare systems where it is strong enough to constrain $\\Delta\\alpha/\\alpha$ from these species alone. These provide 12 independent measurements (3 quasars were observed with both telescopes) at redshifts 1.0--2.4, 11 of which pass stringent reliability criteria. These 11 are all consistent with $\\Delta\\alpha/\\alpha=0$ within their individual uncertainties of 3.5--13 parts per million (ppm), with a we...

  2. Weak Hard X-ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-ray Weakness

    Luo, B; Alexander, D M; Stern, D; Teng, S H; Arévalo, P; Bauer, F E; Boggs, S E; Christensen, F E; Comastri, A; Craig, W W; Farrah, D; Gandhi, P; Hailey, C J; Harrison, F A; Koss, M; Ogle, P; Puccetti, S; Saez, C; Scott, A E; Walton, D J; Zhang, W W

    2014-01-01

    We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z=0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with 33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.

  3. Improvements in cobalt determination by thermospray flame furnace atomic absorption spectrometry using an on-line derivatization strategy.

    Matos, Geraldo Domingues; Arruda, Marco Aurélio Zezzi

    2008-07-15

    An on-line derivatization strategy was developed for improving cobalt sensitivity using thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) as the analytical technique. This strategy involves the generation of a volatile cobalt compound, providing better sample vaporization efficiency. The effect of sodium diethyldithiocarbamate (DDTC) as complexing agent on the integrated absorbance signal was evaluated. Parameters including the pH of complex formation, complex concentration and volume, sample volume, flame gas composition and tube atomization configuration were optimized. A wide linear range (from 23 microg L(-1) to 3 mg L(-1); r(2)=0.9786) was obtained, with the best one (r(2)=0.9992) attained from 23 to 400 microg L(-1) with a sample throughput of 30 h(-1). The improvement in the detection power was 17-fold when compared to FAAS, which provides 7 microg L(-1) as the limit of detection when considered TS-FF-AAS technique. A relative standard deviation (n=10) of 4% for a cobalt solution containing 50 microg L(-1) was attained, and the accuracy of the procedure was evaluated through certified reference materials (IAEA-SL-1, lake sediment; and ISS-MURST-A1, Antarctic marine sediment). Good agreement between the results at the 95% confidence level was observed. PMID:18585309

  4. Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

    Doi, Akihiro; Murata, Yasuhiro; Mochizuki, Nanako; Takeuchi, Hiroshi; Asada, Keiichi; Hayashi, Takayuki J.; Nagai, Hiroshi; Shibata, Katsunori M.; Oyama, Tomoaki; Jike, Takaaki; Fujisawa, Kenta; Sugiyama, Koichiro; Ogawa, Hideo; Kimura, Kimihiro; Honma, Mareki; Kobayashi, Hideyuki; Koyama, Shoko

    2013-06-01

    This paper reports on very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ˜10 pc. The convex radio spectrum has been stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age on the order of ˜100 years as a radio source, according to an observed correlation between the linear size and the peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests a relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.

  5. Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

    Doi, Akihiro; Mochizuki, Nanako; Takeuchi, Hiroshi; Asada, Keiichi; Hayashi, Takayuki J; Nagai, Hiroshi; Shibata, Katsunori M; Oyama, Tomoaki; Jike, Takaaki; Fujisawa, Kenta; Sugiyama, Koichiro; Ogawa, Hideo; Kimura, Kimihiro; Honma, Mareki; Kobayashi, Hideyuki; Koyama, Shoko

    2013-01-01

    This paper reports very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ~10 pc. The convex radio spectrum is stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age of the order of ~100 years as a radio source, according to an observed correlation between linear size and peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.

  6. On line diagnostics of rotating machinery using expert system technology

    Over the last years it became apparent that on line diagnostics will become more and more important for increasing safety in nuclear power plants and the availability of machinery. Expert system technology in combination with conventional methods for pattern recongnition and data preparation turned out to be a favorite candidate for automatic on line diagnostics of rotating machinery and related diagnostical problems. The article describes the conceptual design of an on line diagnostic system for a liquid sodium pump in a nuclear power plant. An overview on the system design, the system parameters, the user interface, and an example for the construction of the knowledge base will be given. (orig.)

  7. Determination of cobalt in biological samples by line-source and high-resolution continuum source graphite furnace atomic absorption spectrometry using solid sampling or alkaline treatment

    Two procedures for the determination of Co in biological samples by graphite furnace atomic absorption spectrometry (GF AAS) were compared: solid sampling (SS) and alkaline treatment with tetramethylammonium hydroxide (TMAH) using two different instruments for the investigation: a conventional line-source (LS) atomic absorption spectrometer and a prototype high-resolution continuum source atomic absorption spectrometer. For the direct introduction of the solid samples, certified reference materials (CRM) were ground to a particle size ≤50 μm. Alkaline treatment was carried out by placing about 250 mg of the sample in polypropylene flasks, adding 2 mL of 25% m/v tetramethylammonium hydroxide and de-ionized water. Due to its unique capacity of providing a 3-D spectral plot, a high-resolution continuum source (HR-CS) graphite furnace atomic absorption spectrometry was used as a tool to evaluate potential spectral interferences, including background absorption for both sample introduction procedures, revealing that a continuous background preceded the atomic signal for pyrolysis temperatures lower than 700 deg. C. Molecular absorption bands with pronounced rotational fine structure appeared for atomization temperatures >1800 deg. C probably as a consequence of the formation of PO. After optimization had been carried out using high resolution continuum source atomic absorption spectrometry, the optimized conditions were adopted also for line-source atomic absorption spectrometry. Six biological certified reference materials were analyzed, with calibration against aqueous standards, resulting in agreement with the certified values (according to the t-test for a 95% confidence level) and in detection limits as low as 5 ng g-1

  8. Residential solar air conditioning: Energy and exergy analyses of an ammonia–water absorption cooling system

    Large scale heat-driven absorption cooling systems are available in the marketplace for industrial applications but the concept of a solar driven absorption chiller for air-conditioning applications is relatively new. Absorption chillers have a lower efficiency than compression refrigeration systems, when used for small scale applications and this restrains the absorption cooling system from air conditioning applications in residential buildings. The potential of a solar driven ammonia–water absorption chiller for residential air conditioning application is discussed and analyzed in this paper. A thermodynamic model has been developed based on a 10 kW air cooled ammonia–water absorption chiller driven by solar thermal energy. Both energy and exergy analyses have been conducted to evaluate the performance of this residential scale cooling system. The analyses uncovered that the absorber is where the most exergy loss occurs (63%) followed by the generator (13%) and the condenser (11%). Furthermore, the exergy loss of the condenser and absorber greatly increase with temperature, the generator less so, and the exergy loss in the evaporator is the least sensitive to increasing temperature. -- Highlights: • 10 kW solar thermal driven ammonia–water air cooled absorption chiller is investigated. • Energy and exergy analyses have been done to enhance the thermal performance. • Low driving temperature heat sources have been optimized. • The efficiencies of the major components have been evaluated

  9. A CHANDRA SURVEY OF THE X-RAY PROPERTIES OF BROAD ABSORPTION LINE RADIO-LOUD QUASARS

    This work presents the results of a Chandra study of 21 broad absorption line (BAL) radio-loud quasars (RLQs). We conducted a Chandra snapshot survey of 12 bright BAL RLQs selected from Sloan Digital Sky Survey Data/Faint Images of the Radio Sky data and possessing a wide range of radio and C IV absorption properties. Optical spectra were obtained nearly contemporaneously with the Hobby-Eberly Telescope; no strong flux or BAL variability was seen between epochs. In addition to the snapshot targets, we include in our sample nine additional BAL RLQs possessing archival Chandra coverage. We compare the properties of (predominantly high-ionization) BAL RLQs to those of non-BAL RLQs as well as to BAL radio-quiet quasars (RQQs) and non-BAL RQQs for context. All 12 snapshots and 8/9 archival BAL RLQs are detected, with observed X-ray luminosities less than those of non-BAL RLQs having comparable optical/UV luminosities by typical factors of 4.1-8.5. (BAL RLQs are also X-ray weak by typical factors of 2.0-4.5 relative to non-BAL RLQs having both comparable optical/UV and radio luminosities.) However, BAL RLQs are not as X-ray weak relative to non-BAL RLQs as are BAL RQQs relative to non-BAL RQQs. While some BAL RLQs have harder X-ray spectra than typical non-BAL RLQs, some have hardness ratios consistent with those of non-BAL RLQs, and there does not appear to be a correlation between X-ray weakness and spectral hardness, in contrast to the situation for BAL RQQs. RLQs are expected to have X-ray continuum contributions from both accretion-disk corona and small-scale jet emission. While the entire X-ray continuum in BAL RLQs cannot be obscured to the same degree as in BAL RQQs, we calculate that the jet is likely partially covered in many BAL RLQs. We comment briefly on implications for geometries and source ages in BAL RLQs.

  10. On-Line Systems: Promise and Pitfalls

    Cuadra, Carlos A.

    1971-01-01

    The virtues of interactive systems are speed, intimacy, and - if time-sharing is involved - economy. The major problems are the cost of the large computers and files necessary for bibliographic data, the still-high cost of communications, and the generally poor design of the user-system interfaces. (Author)

  11. CHIRAL MULTIPHOTON ABSORPTION AND INVERSE SKIN EFFECT IN WLAN SYSTEMS

    Héctor Torres Silva

    2005-12-01

    Full Text Available A model formed by chiral bioplasma with a set of macromolecules of DNA, which represents the human head inner structure, makes possible to analyze its behavior, when it is radiated by a microwave electromagnetic field from cellular phones and WLAN's at frequencies of 2.4 and 5.2 GHz is presented. The finite difference time domain, FDTD, numeric technique is used under multiphoton regime deduced from Maxwell equations. The numerical results of the Specific Absorption Rate, SAR, show the SAR behavior in function of input power and the chirality factor. The main conclusions of our work are: a the microwave absorption from cellular phones or WLAN's is enhanced, compared with classical models, when values of the normalized chiral factor are of order of one which appear under multiphoton regime ; b a phenomena like an “inverse skin effect” in 5.2 GHz, with respect to a 2.4 GHz source, was observed. c In the metamaterial region we show that the absorption rate always is positive.Un modelo formado por bioplasma quiral con un conjunto de macromoléculas de ADN, que representa la estructura interna de la cabeza humana, hace posible analizar su comportamiento, cuando es irradiada por campos electromagnéticos de microondas de teléfonos celulares o sistemas WLAN a frecuencias de 2.4 y 5.2 GHz. El método de diferencias finitas en el dominio del tiempo, FDTD, en régimen de multifotones deducido de las ecuaciones de Maxwell es usado. Los resultados numéricos de la taza de absorción específica SAR, muestran el comportamiento de la SAR en función de la potencia de entrada y del factor quiral. Las principales conclusiones de nuestro trabajo son: a la absorción de microondas es aumentada comparada con modelos clásicos, cuando valores del factor quiral normalizado son del orden de la unidad, que aparecen bajo régimen multifotónico; b Un fenómeno de efecto pelicular inverso en 5.2 GHz con respecto a una fuente de 2.4 GHz fue observado; c En la regi

  12. Computer systems handle changing T-line access

    Paula, G.

    1990-03-01

    As the number of power exchanges among utilities grows and transmission lines are loaded more heavily, it becomes increasingly difficult to manage power-system access. A study sponsored by the Electric Power Research Institute (EPRI) identifies two analysis techniques that can provide more detailed line-use information to help utilities ensure continued reliability. After meeting internal needs, a utility agrees on usage price and terms with other power suppliers and users that want to transfer power across its lines. This is known as wheeling. However, such transactions affect the loading of lines belonging to other utilities. As a result, no utility can actually control who uses its transmission system. Many utilities would like a way to monitor power flows on their systems to improve the economy and reliability of operation. The EPRI-sponsored study, conducted by Casazza, Schultz, Associates (CSA), Arlington, VA, identifies ways that computer methods can help utilities cope with increased line access.

  13. Determination of Ultra-Trace Amounts of Selenium(IV) by Flow Injection Hydride Generation Atomic Absorption Spectrometry with On-line Preconcentration by Co-precipitation with Lanthanium Hydroxide. Part II. On-line Addition of Coprecipating Agent

    Nielsen, Steffen; Sloth, Jens Jørgen; Hansen, Elo Harald

    1996-01-01

    A flow injection procedure for the determination of ultra-trace amounts of selenium(IV) is described, which combines hydride generation atomic absorption spectrometry (HGAAS) with on-line preconcentration of the analyte by co-precipitation-dissolution in a filterless knotted Microline reactor...

  14. Redox speciation analysis of dissolved iron in estuarine and coastal waters with on-line solid phase extraction and graphite furnace atomic absorption spectrometry detection.

    Chen, Yaojin; Feng, Sichao; Huang, Yongming; Yuan, Dongxing

    2015-05-01

    An automatic on-line solid phase extraction (SPE) system employing the flow injection (FI) technique directly coupled to a graphite furnace atomic absorption spectrometer (GFAAS) was established for speciation and determination of dissolved iron in estuarine and coastal waters. Fe(II) was mixed with ferrozine solution in a sample stream to form the Fe(II)-ferrozine complex which was extracted onto a C18 SPE cartridge, eluted with eluent and detected with GFAAS. In a parallel flow channel, Fe(III) was reduced to Fe(II) with ascorbic acid and then detected in the same way as Fe(II). The home-made interface between FI-SPE and GFAAS efficiently realized the sample introduction to the furnace in a semi-automated way. Parameters of the FI-SPE system and graphite furnace program were optimized based on a univariate experimental design and an orthogonal array design. The salinity effect on the method sensitivity was investigated. The proposed method provided a detection limit of 1.38 nmol L(-1) for Fe(II) and 1.87 nmol L(-1) for Fe(II+III). With variation of the sample loading volume, a broadened determination range of 2.5-200 nmol L(-1) iron could be obtained. The proposed method was successfully applied to analyze iron species in samples collected from the Jiulongjiang Estuary, Fujian, China. With the 2-cartridge FI-SPE system developed, on-line simultaneous determination of Fe species with GFAAS was achieved for the first time. PMID:25770602

  15. Solar Powered Vapor Absorption System Using Propane And Alkylated Benzene Ab300 Oil

    Al-Dadah, R.K.; Jackson, G.; Rezk, Ahmed

    2011-01-01

    Abstract This paper describes experimental work on a solar assisted vapour absorption air conditioning system using Propane (refrigerant) and Alkylated Benzene (AB300?refrigeration lubrication oil, absorbent). Preliminary experiments to assess the miscibility of propane in various lubricating oils namely Shell Clavus oils 32 and 64 and Alkylated Benzene oils AB150 and AB300 indicated that Propane is most miscible in Alkylated Benzene AB300. The vapour absorption system is a single ...

  16. The Origin of \\lya Absorption Systems at $z>1$---Implications from the Hubble Deep Field

    Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Fernández-Soto, Alberto

    1999-01-01

    The Hubble Deep Field images have provided us with a unique chance to relate statistical properties of high-redshift galaxies to statistical properties of \\lya absorption systems. Combining an {\\em empirical} measure of the galaxy surface density versus redshift with an {\\em empirical} measure of the gaseous extent of galaxies, we predict the number density of \\lya absorption systems that originate in extended gaseous envelopes of galaxies versus redshift. We show that at least 50% and as muc...

  17. Connector for vacuum-jacketed lines cuts tubing system cost

    Calvert, H. F.

    1964-01-01

    A low-cost fitting, fabricated from standard connectors, is used for disconnecting flow lines in cryogenic systems. Utilizing vacuum-jacketed lines made from two sizes of tubing welded at the ends, the connectors are stronger and setup time is reduced.

  18. Geographic Names Information System (GNIS) Hydrography Lines

    Department of Homeland Security — The Geographic Names Information System (GNIS) is the Federal standard for geographic nomenclature. The U.S. Geological Survey developed the GNIS for the U.S. Board...

  19. Detection of HI 21 cm-line absorption in the Warm Neutral Medium and in the Outer Arm of the Galaxy

    Dwarakanath, K S; Goss, W M

    2001-01-01

    Using the Westerbork Synthesis Radio Telescope, we have detected HI 21 cm-line absorption in the Warm Neutral Medium of the Galaxy toward the extragalactic source 3C147. This absorption, at an LSR velocity of -29+/-4 km/s with a full width at half maximum of 53+/-6 km/s, is associated with the Perseus Arm of the Galaxy. The observed optical depth is (1.9+/-0.2)*10**(-3). The estimated spin temperature of the gas is 3600+/-360 K. The volume density is 0.4 per cc assuming pressure equilibrium. Toward two other sources, 3C273 and 3C295, no wide HI 21 cm-line absorption was detected. The highest of the 3sigma lower limits on the spin temperature of the Warm Neutral Medium is 2600 K. In addition, we have also detected HI 21 cm-line absorption from high velocity clouds in the Outer Arm toward 3C147 and 3C380 at LSR velocities of -117.3, -124.5 and -113.7 km/s respectively. We find two distinct temperature components in the high velocity clouds with spin temperatures of greater than 1000 K and less than 200 K, respe...

  20. In vitro and in vivo percutaneous absorption of retinol from cosmetic formulations: Significance of the skin reservoir and prediction of systemic absorption

    The percutaneous absorption of retinol (Vitamin A) from cosmetic formulations was studied to predict systemic absorption and to understand the significance of the skin reservoir in in vitro absorption studies. Viable skin from fuzzy rat or human subjects was assembled in flow-through diffusion cells for in vitro absorption studies. In vivo absorption studies using fuzzy rats were performed in glass metabolism cages for collection of urine, feces, and body content. Retinol (0.3%) formulations (hydroalcoholic gel and oil-in-water emulsion) containing 3H-retinol were applied and absorption was measured at 24 or 72 h. All percentages reported are % of applied dose. In vitro studies using human skin and the gel and emulsion vehicles found 0.3 and 1.3% retinol, respectively, in receptor fluid at 24 h. Levels of absorption in the receptor fluid increased over 72 h with the gel and emulsion vehicles. Using the gel vehicle, in vitro rat skin studies found 23% in skin and 6% in receptor fluid at 24 h, while 72-h studies found 18% in skin and 13% in receptor fluid. Thus, significant amounts of retinol remained in rat skin at 24 h and decreased over 72 h, with proportional increases in receptor fluid. In vivo rat studies with the gel found 4% systemic absorption of retinol after 24 h and systemic absorption did not increase at 72 h. Retinol remaining in rat skin after in vivo application was 18% and 13% of the applied dermal dose after 24 and 72 h, respectively. Similar observations were made with the oil-in water emulsion vehicle in the rat. Retinol formed a reservoir in rat skin both in vivo and in vitro. Little additional retinol was bioavailable after 24 h. Comparison of these in vitro and in vivo results for absorption through rat skin indicates that the 24-h in vitro receptor fluid value accurately estimated 24-h in vivo systemic absorption. Therefore, the best single estimate of retinol systemic absorption from in vitro human skin studies is the 24-h receptor fluid

  1. Automotive exhaust gas flow control for an ammonia–water absorption refrigeration system

    A considerable part of the energy generated by an automotive internal combustion engine is wasted as heat in the exhaust system. This wasted heat could be recovered and applied to power auxiliary systems in a vehicle, contributing to its overall energy efficiency. In the present work, the experimental analysis of an absorption refrigeration system was performed. The exhaust system of an automotive internal combustion engine was connected to the generator element of an absorption refrigeration system. The performance of the absorption refrigerator was evaluated as a function of the supplied heat. The use of a control strategy for the engine exhaust gas mass flow rate was implemented to optimize the system. Exhaust gas flow was controlled by step-motor actuated valves commanded by a microcontroller in which a proportional-integral control scheme was implemented. Information such as engine torque, speed, key temperatures in the absorption cycle, as well as internal temperatures of the refrigerator was measured in a transient regime. The results indicated that the refrigeration system exhibited better performance when the amount of input heat is controlled based on the temperature of the absorption cycle generator. It was possible to conclude that, by dynamically controlling the amount of input heat, the utilisation range of the absorption refrigeration system powered by exhaust gas heat could be expanded in order to incorporate high engine speed operating conditions. - Highlights: •An absorption refrigerator was driven by automotive exhaust gas heat. •A system for controlling the refrigeration system heat input was developed. •Excessive exhaust gas heat leads to ineffective operation of the refrigerator. •Control of refrigerator's generator temperature led to better performance. •The use of exhaust gas was possible for high engine speeds

  2. On-Line Preconcentration and Speciation of Chromium by an 8-Hydroxyquinoline Microcolumn Immobilized on Surfactant-Coated Alumina and Flow Injection Atomic Absorption Spectrometry

    AHMADI, Seyyed Hamid; SHABANI, Ali Mohammad HAJI

    2007-01-01

    An on-line technique for the determination of chromium species with atomic absorption spectrometry is described. The method is based on separation and preconcentration of Cr(III) on a microcolumn of immobilized 8-hydroxyquinoline on surfactant-coated alumina. The adsorbed analyte is then eluted with 400 m L of 20% ethanolic solution of 1.5 mol L-1 hydrochloric acid and is transported to a flame atomic absorption spectrometer for quantification. The effects of pH, sample and eluent f...

  3. Identification of the very High Redshift(Zcm〉4.7) quasar absorption lines%SDSS甚高红移类星体MgII吸收线初步证认

    黎木胜; 潘彩娟; 廖容花; 黄伟荣; 钟榆青; 王美萍; 李嘉良

    2012-01-01

    文章利用美国SDSS望远镜观测的类星体光谱,在IDL可视化程序平台中进行处理,处理过程包括消光改正、扣除连续谱和铁谱、扣除发射线、认证吸收线等。通过对甚高红移(Zem〉4.7)类星体光谱的分析,证认出281个MgIDλλ2796,2803双线吸收系统。%By analyzing quasar absorption lines,we are able to get information of the ab- sorber redshift, density, temperature,abundance of elements, etc.. These data are useful for stud- ying the structure and evolution of the universe. We download the data of of quasar spectra observed by the sloan digital sky survey(SDSS) telescope in USA,and analyze them in a IDL visualization program platform. The process of analysis includes the extinction correction and the co-moving frame correction,taking out the continuous,the iron emission,and the emission lines,as well as the identification of absorption lines. In this way,we have identified 281 Mg II double absorption systems.

  4. Development of an advanced transmission line fault location system

    This paper describes the solution techniques, system modeling considerations, and simulation studies performed as a part of the development of an advanced transmission line fault location system (AFLS) intended for use on the New York Power Authority's system. The Power Authority's Moses-Adirondack 230 kV lines were selected as a test bed for the study. A reduced model of the transmission system around the Moses-Adirondack lines was developed, and a number of Electromagnetic Transients Program (EMTP) cases run to establish simulated voltage and current information as fed to the fault location system. Sensitivity studies were performed to investigate the impact of various system models, hardware features, and system conditions on fault location accuracy

  5. Evidence for ultra-fast outflows in radio-quiet AGNs. I. Detection and statistical incidence of Fe K-shell absorption lines

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G. G. C.; Yaqoob, T.; Braito, V.; Dadina, M.

    2010-10-01

    Context. Blue-shifted Fe K absorption lines have been detected in recent years between 7 and 10 keV in the X-ray spectra of several radio-quiet AGNs. The derived blue-shifted velocities of the lines can often reach mildly relativistic values, up to 0.2-0.4c. These findings are important because they suggest the presence of a previously unknown massive and highly ionized absorbing material outflowing from their nuclei, possibly connected with accretion disk winds/outflows. Aims: The scope of the present work is to statistically quantify the parameters and incidence of the blue-shifted Fe K absorption lines through a uniform analysis on a large sample of radio-quiet AGNs. This allows us to assess their global detection significance and to overcome any possible publication bias. Methods: We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. A simple uniform model composed by an absorbed power-law plus Gaussian emission and absorption lines provided a good fit for all the data sets. We derived the absorption lines parameters and calculated their detailed detection significance making use of the classical F-test and extensive Monte Carlo simulations. Results: We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies higher than 7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3 × 10-8, and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability UFOs) those highly ionized absorbers with outflow velocities higher than 104 km s-1, then the majority of the lines are consistent with being associated to UFOs and the fraction of objects with detected UFOs in the whole sample is at least ~35%. This fraction is similar for type 1 and type 2 sources. The global covering fraction of

  6. Solid Oxide Fuel Cell Systems PVL Line

    Susan Shearer - Stark State College; Gregory Rush - Rolls-Royce Fuel Cell Systems

    2012-05-01

    In July 2010, Stark State College (SSC), received Grant DE-EE0003229 from the U.S. Department of Energy (DOE), Golden Field Office, for the development of the electrical and control systems, and mechanical commissioning of a unique 20kW scale high-pressure, high temperature, natural gas fueled Stack Block Test System (SBTS). SSC worked closely with subcontractor, Rolls-Royce Fuel Cell Systems (US) Inc. (RRFCS) over a 13 month period to successfully complete the project activities. This system will be utilized by RRFCS for pre-commercial technology development and training of SSC student interns. In the longer term, when RRFCS is producing commercial products, SSC will utilize the equipment for workforce training. In addition to DOE Hydrogen, Fuel Cells, and Infrastructure Technologies program funding, RRFCS internal funds, funds from the state of Ohio, and funding from the DOE Solid State Energy Conversion Alliance (SECA) program have been utilized to design, develop and commission this equipment. Construction of the SBTS (mechanical components) was performed under a Grant from the State of Ohio through Ohio's Third Frontier program (Grant TECH 08-053). This Ohio program supported development of a system that uses natural gas as a fuel. Funding was provided under the Department of Energy (DOE) Solid-state Energy Conversion Alliance (SECA) program for modifications required to test on coal synthesis gas. The subject DOE program provided funding for the electrical build, control system development and mechanical commissioning. Performance testing, which includes electrical commissioning, was subsequently performed under the DOE SECA program. Rolls-Royce Fuel Cell Systems is developing a megawatt-scale solid oxide fuel cell (SOFC) stationary power generation system. This system, based on RRFCS proprietary technology, is fueled with natural gas, and operates at elevated pressure. A critical success factor for development of the full scale system is the capability

  7. Technology PLC - Power Line Communication, Used in Monitoring Systems Online

    Vilson Gruber; Roderval Marcelino; Juarez Bento Da Silva

    2013-01-01

    This paper is developing a system for monitoring, supervision and acquisition parameters using Power Line Communication technology. The system consists of a web microserver using the power grid for the transmission and reception of data through technology PLC (Power Line Communication), as a solution for remote monitoring of temperature parameters of a mini turbine bench. In this article were performed comparative tests between the PLC and LAN technology in two distinct environments: resident...

  8. SDSS J163459.82+204936.0: A Ringed Infrared-Luminous Quasar with Outflows in both Absorption and Emission Lines

    Liu, Wen-Juan; Jiang, Ning; Wu, Xufen; Lyu, Jianwei; Shi, Xiheng; Shu, Xinwen; Jiang, Peng; Ji, Tuo; Wang, Jiang-Guo; Wang, Shu-Fen; Sun, Luming

    2016-01-01

    SDSS J1634+2049 is a local (z = 0.1293) infrared-luminous quasar with LIR= 10^11.91 Lsun. We present a detailed multiwavelength study of both the host galaxy and the nucleus. The host galaxy demonstrates violent, obscured star formation activities with SFR ~ 140 Msun yr^-1, estimated from either the PAH emission or IR luminosity. The optical to NIR spectra exhibit a blueshifted narrow cuspy component in Hb, HeI5876,10830 and other emission lines consistently with an offset velocity of ~900 km/s, as well as additional blueshifting phenomena in high-ionization lines , while there exist blueshifted broad absorption lines (BALs) in NaID and HeI*3889,10830, indicative of the AGN outflows producing BALs and emission lines. Constrained mutually by the several BALs with CLOUDY, the physical properties of the absorption-line outflow are derived as follows: 10^4 < n_H <= 10^5 cm^-3, 10^-1.3 <= U <= 10^-0.7 and 10^22.5<= N_H <= 10^22.9 cm^-2 , similar to those derived for the emission-line outflows. Th...

  9. Chandra View of the Warm-Hot IGM toward 1ES 1553+113: Absorption Line Detections and Identifications (Paper I)

    Nicastro, F; Krongold, Y; Mathur, S; Gupta, A; Danforth, C; Barcons, X; Borgani, S; Branchini, E; Cen, R; Davé, R; Kaastra, J; Paerels, F; Piro, L; Shull, J M; Takei, Y; Zappacosta, L

    2012-01-01

    About 30-40 percent of the expected number of baryons is still missing in the local Universe (z \\lesssim 0.4). They are predicted to be hiding in a web of intergalactic gas at temperatures of about 10^5-10^7 K (the WHIM). Detecting this matter has had limited success so far, because of its low-density and high temperature, which makes it difficult to detect with current far-ultraviolet and X-ray instrumentation. Here we present the first results from our pilot 500 ks Chandra-LETG observation of the soft X-ray brightest source in the z > 0.4 sky, the blazar 1ES 1553+113. We identify a total of 11 possible absorption lines, with single-line statistical significances between 2.2-4.1 sigma. Six of these lines are detected at high significance (3.6 < \\sigma < 4.1), while the remaining five are regarded as marginal detections in association with either other X-ray lines detected at higher significance and/or FUV signposts. Three of these lines are consistent with metal absorption at z~0. The remaining 8 lines...

  10. High frequency ultrasonic-assisted CO2 absorption in a high pressure water batch system.

    Tay, W H; Lau, K K; Shariff, A M

    2016-11-01

    Physical absorption process is always nullified by the presence of cavitation under low frequency ultrasonic irradiation. In the present study, high frequency ultrasonic of 1.7MHz was used for the physical absorption of CO2 in a water batch system under elevated pressure. The parameters including ultrasonic power and initial feed pressure for the system have been varied from 0 to 18W and 6 to 41bar, respectively. The mass transfer coefficient has been determined via the dynamic pressure-step method. Besides, the actual ultrasonic power that transmitted to the liquid was measured based on calorimetric method prior to the absorption study. Subsequently, desorption study was conducted as a comparison with the absorption process. The mechanism for the ultrasonic assisted absorption has also been discussed. Based on the results, the mass transfer coefficient has increased with the increasing of ultrasonic power. It means that, the presence of streaming effect and the formation of liquid fountain is more favorable under high frequency ultrasonic irradiation for the absorption process. Therefore, high frequency ultrasonic irradiation is suggested to be one of the potential alternatives for the gas separation process with its promising absorption enhancement and compact design. PMID:27245970

  11. Effect of total pressure on the absorption line blackbody distribution function and radiative transfer in H2O, CO2, and CO

    The absorption spectrum has been generated for H2O, CO2, and CO at total pressures varying from 0.1 to 50 atm using the HITEMP 2010 spectroscopic database. From these spectra the absorption line blackbody distribution function (ALBDF) has been calculated at variable total pressure in order to understand the importance of accounting for pressure changes on this parameter. The ALBDF is used in the SLW solution method to the radiative transfer equation. ALBDF data for H2O, CO2, and CO are presented, revealing a shift in the ALBDF to lower values as total pressure increases. This shift is weaker at high temperature. The shift due to increase in mole fraction of H2O and CO2 was shown to be modest, and similar at different pressures. The ALBDF was shown to become less smooth as pressure increases. Total emissivity calculations are presented for variable total pressure, and it is seen that pressure changes account for a significant change in total emissivity. Total radiative flux and radiative flux divergence were calculated from line-by-line spectral integrations for one-dimensional layers of constant length and constant mass cases, showing that total pressure changes result in a significant impact on radiative transfer in a layer of gas. Radiative flux exiting a layer of gas can change by more than a factor of four over the pressure range investigated when the pressure change is the only variable considered. - Highlights: • The absorption spectrum is generated for H2O, CO2, and CO. • Temperature range is 400–3000 K, total pressure range from 0.1 atm to 50 atm. • The ALBDF is generated from the absorption spectrum. • The ALBDF is smoother, and decreases as total pressure is increased. • Pressure effect on radiative transfer is explored from line-by-line calculations

  12. QSO ABSORPTION SYSTEMS DETECTED IN Ne VIII: HIGH-METALLICITY CLOUDS WITH A LARGE EFFECTIVE CROSS SECTION

    Meiring, J. D.; Tripp, T. M. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Werk, J. K.; Prochaska, J. X. [University of California Observatories-Lick Observatory, UC Santa Cruz, CA 95064 (United States); Howk, J. C. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Jenkins, E. B. [Princeton University Observatory, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Lehner, N.; Sembach, K. R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2013-04-10

    Using high-resolution, high signal-to-noise ultraviolet spectra of the z{sub em} = 0.9754 quasar PG1148+549 obtained with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, we study the physical conditions and abundances of Ne VIII+O VI absorption line systems at z{sub abs} = 0.68381, 0.70152, 0.72478. In addition to Ne VIII and O VI, absorption lines from multiple ionization stages of oxygen (O II, O III, O IV) are detected and are well aligned with the more highly ionized species. We show that these absorbers are multiphase systems including hot gas (T Almost-Equal-To 10{sup 5.7} K) that produces Ne VIII and O VI, and the gas metallicity of the cool phase ranges from Z = 0.3 Z{sub Sun} to supersolar. The cool ( Almost-Equal-To 10{sup 4} K) phases have densities n{sub H} Almost-Equal-To 10{sup -4} cm{sup -3} and small sizes (<4 kpc); these cool clouds are likely to expand and dissipate, and the Ne VIII may be within a transition layer between the cool gas and a surrounding, much hotter medium. The Ne VIII redshift density, dN/dz{approx}7{sup +7}{sub -3}, requires a large number of these clouds for every L > 0.1 L* galaxy and a large effective absorption cross section ({approx}> 100 kpc), and indeed, we find a star-forming {approx}L {sup *} galaxy at the redshift of the z{sub abs} = 0.72478 system, at an impact parameter of 217 kpc. Multiphase absorbers like these Ne VIII systems are likely to be an important reservoir of baryons and metals in the circumgalactic media of galaxies.

  13. Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants

    SHAO Jiahui; FANG Xuliang; HE Yiliang; JIN Qiang

    2008-01-01

    Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditionalchlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaksin the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose.Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditionson the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration,liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9%was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically foundto be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammoniaremoval rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plantmembrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatmentplant, also paved the way towards a larger scale application.

  14. A study of energy absorption rate in a quantum dot and metallic nanosphere hybrid system

    We have studied energy absorption rate in a quantum dot-metallic nanosphere system embedded on a dielectric substrate. We applied a control field to induce dipole moments in the quantum dot and the metal nanosphere, and monitored the energy absorption using a probe field. These external fields induce dipole moments in the metal nanosphere and the quantum dot, and these two structures interact with one another via the dipole–dipole interaction. The density matrix method was used to evaluate the absorption, indicating that it can be shifted by moving the metal nanosphere close to the quantum dot. Also, absorption efficiency can either be quenched or enhanced by the addition of a metal nanosphere. This hybrid system can be used to create ultrafast switching and sensing nanodevices. (paper)

  15. On line systems of information acquisition

    The modern methods of tracing the real state of working funds and the decisions made on the basis of the portfolio of factors, with the possibility of depicting the results of strategical decisions, enable the companies to compete in the hard environs of the global competition. Common platform providing the total information about dynamics of procedures and production goods in the real time is applied in many power plants of the SE, Plc. The software platform SYSTEM 1 is the subject to the constant development in accordance with the needs of modern management of working fond. The System 1(tm) release 5.0 is expected in the second quarter of 2004. New approach to application package according to users demands will provide higher comfort by using a product. New possibilities will be demonstrated on particular SE, Plc applications. Scenario of determination of potential breakdown of a machine - elements of a machine at the very beginning and the way of support decision on different levels of management. Operation, maintenance, optimization of production and the management of the whole company can decide on the basis of the knowledge and the factors provided in real time and fully by one environs directly on the manager's desk

  16. THE ROLE OF KNOWLEDGE MANAGEMENT SYSTEMS FOR INNOVATION: AN ABSORPTIVE CAPACITY PERSPECTIVE

    BERNHARD MOOS; DANIEL BEIMBORN; HEINZ-THEO WAGNER; TIM WEITZEL

    2013-01-01

    What is the role of Knowledge Management Systems (KMS) for a firm's innovativeness and absorptive capacity (ACAP)? Research shows that a firm's capacity to acquire and utilise relevant knowledge, i.e., its absorptive capacity, is decisive for innovation success. We develop a theoretical model that links the availability and usage of KMS with a firm's ACAP and its organisational knowledge to explain its contribution for a firm's innovation success. Using data from 222 manufacturing firms, we c...

  17. The Gaseous Extent of Galaxies and the Origin of \\lya Absorption Systems at z < 1

    Chen, H. -W.; Lanzetta, K. M.; Webb, J. K.; Barcons, X.

    1997-01-01

    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies in fields of HST spectroscopic target QSOs. The goal of the program is to investigate how the properties of \\lya absorption systems observed in the spectra of background QSOs vary with the properties of intervening galaxies. We found that \\lya absorption equivalent width depends strongly on galaxy impact parameter and galaxy B-band luminosity, and that the gaseous extent of individual galaxies scales wi...

  18. On variations in the fine-structure constant and limits on AGB pollution of quasar absorption systems

    Fenner, Y; Gibson, B K

    2005-01-01

    At redshifts z_abs < 2, quasar absorption-line constraints on space-time variations in the fine-structure constant, alpha, rely on the comparison of MgII and FeII transition wavelengths. One potentially important uncertainty is the relative abundance of Mg isotopes in the absorbers which, if different from solar, can cause spurious shifts in the measured wavelengths and, therefore, alpha. Here we explore chemical evolution models with enhanced populations of intermediate-mass (IM) stars which, in their asymptotic giant branch (AGB) phase, are thought to be the dominant factories for heavy Mg isotopes at the low metallicities typical of quasar absorption systems. By design, these models partially explain recent Keck/HIRES evidence for a smaller alpha in z_abs < 2 absorption clouds than on Earth. However, such models also over-produce N, violating observed abundance trends in high-z_abs damped Lyman-alpha systems (DLAs). Our results do not support the recent claim of Ashenfelter, Mathews & Olive (2004...

  19. The Origin of C IV Absorption Systems at Redshifts z<1---Discovery of Extended C IV Envelopes Around Galaxies

    Chen, H W; Webb, J K; Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Webb, John K.

    2001-01-01

    (Abridged) We report the discovery of extended CIV gaseous envelopes around galaxies of a wide range of luminosity and morphological type. First, we show that CIV absorption systems are strongly clustered around galaxies on velocity scales of v < 250 km/s and impact parameter scales of rho < 100 h^{-1} kpc but not on larger velocity or impact parameter scales. Next, adopting measurements of galaxy properties presented in previous papers, we examine how properties of the CIV absorption systems depend on properties of the galaxies. On the basis of 14 galaxy and absorber pairs and 36 galaxies that do not produce corresponding CIV absorption lines to within sensitive upper limits, we find that: (1) Galaxies of a range of morphological type and luminosity appear to possess extended CIV gaseous envelopes of radius R ~ 100 h^{-1} kpc, with abrupt boundaries between the CIV absorbing and non-absorbing regions. (2) The extent of CIV-absorbing gas around galaxies scales with galaxy B-band luminosity as R \\propto ...

  20. Dark-lines in bifurcation plots of nonlinear dynamic systems

    Gao Zhi-Ying; Shen Yun-Wen; Liu Meng-Jun

    2005-01-01

    Based on the regressive character of chaotic motion in nonlinear dynamic systems, a numerical regression algorithm is developed, which can be used to research the dark-lines passing through chaotic regions in bifurcation plots. The dark-lines of the parabolic mapping are obtained by using the numerical regression algorithm, and compared with those that are accurately acquired through dark-line equations. Thus the validity of this algorithm is proved. Furthermore,for the Brussel oscillation system and the piecewise linear dynamic system of a gear pair, the dark-lines are researched by using the regression algorithm. By researching the dark-lines in the bifurcation plots of nonlinear dynamic systems,the periodic windows embedded in chaotic regions can be ascertained by tangential points of dark-lines, and the turning points of chaotic attractors can be also obtained by intersected points. The results show that this algorithm is helpful to analyse dynamic behaviour of systems and control chaotic motion.

  1. Fuzzy-Wavelet Based Double Line Transmission System Protection Scheme in the Presence of SVC

    Goli, Ravikumar; Shaik, Abdul Gafoor; Tulasi Ram, Sankara S.

    2014-07-01

    Increasing the power transfer capability and efficient utilization of available transmission lines, improving the power system controllability and stability, power oscillation damping and voltage compensation have made strides and created Flexible AC Transmission (FACTS) devices in recent decades. Shunt FACTS devices can have adverse effects on distance protection both in steady state and transient periods. Severe under reaching is the most important problem of relay which is caused by current injection at the point of connection to the system. Current absorption of compensator leads to overreach of relay. This work presents an efficient method based on wavelet transforms, fault detection, classification and location using Fuzzy logic technique which is almost independent of fault impedance, fault distance and fault inception angle. The proposed protection scheme is found to be fast, reliable and accurate for various types of faults on transmission lines with and without Static Var compensator at different locations and with various incidence angles.

  2. On-line Payment System Survey – eCash

    Marius Popa

    2009-12-01

    Full Text Available The paper presents the main aspects regarding an on-line payment system. Some characteristics of such system are presented and an existing system is analyzed. On its fundamental sense, the electronic commerce is a concept that represents the purchase and sale process or exchange of products, services, information, using o computer network, inclusively the Internet. In the most part of the cases, the electronic commerce imply on-line payments that lead to creation of some kinds of electronic money and some specific payment systems. There are described the some electronic payment mechanisms and the architecture and the functions of the on-line payment system E-Cash are depicted.

  3. Direct observation of the terahertz optical free induction decay of molecular rotation absorption lines in the sub-nanosecond time scale

    Optical free induction decay (FID) in the region of 60-75 cm-1 was detected using 120 ps pulses of free electron laser. Signals were detected in real time using ultra-fast Schottky diode detectors. The oscillations corresponding to the splitting of absorption lines in deuterated water vapor (Δf = 0.15 cm-1) and hydrogen bromide (Δf = 0.02 cm-1) were detected. At high optical density, we observed the oscillations arising from “top-hat” shape of absorption lines. Free induction decay signals could be detected in a single shot. This observation allowed obtaining a spectrum in one laser pulse, which facilitates studies of very fast processes.

  4. Equivalent width of copper and potassium resonance lines at 3247.54, 7665 Angst for Voigt profile by atomic absorption measurements

    Habib, A.A.M. E-mail: azhabib@yahoo.com

    2004-03-15

    A simple reliable theoretical approach is developed to calculate the equivalent width of copper and potassium resonance lines at 3247.54 and 7665 Angst using atomic absorption techniques. The calculations have been carried out for the two limiting cases of a pure Doppler (Gaussian) and Lorentzian (dispersion) line profiles. The more general case of a Voigt line profile leads to an efficient analytical formula permits a rapid estimate of the equivalent width with sufficient precision. The reliability of the approach has been verified by providing the curves of growth for the given spectral lines to describe the behavior of the equivalent width as the number of absorbing atoms in the ground state is increased. Allowance is made in the analysis for the dependence of the equivalent width for Voigt profile on the damping constant {alpha}, which is a measure of the half width of Lorentz profile relative to the Doppler profile.

  5. Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars

    Srianand, R; Petitjean, P; Aracil, B; Srianand, Raghunathan; Chand, Hum; Petitjean, Patrick; Aracil, Bastien

    2004-01-01

    Most of the successful physical theories rely on the constancy of few fundamental quantities (such as the speed of light, $c$, the fine-structure constant, \\alpha, the proton to electron mass ratio, \\mu, etc), and constraining the possible time variations of these fundamental quantities is an important step toward a complete physical theory. Time variation of \\alpha can be accurately probed using absorption lines seen in the spectra of distant quasars. Here, we present the results of a detailed many-multiplet analysis performed on a new sample of Mg II systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in \\alpha derived from our analysis over the redshift range 0.4

  6. A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers. II. Program Design, Absorption-line Measurements, and Absorber Statistics

    Burchett, Joseph N.; Tripp, Todd M.; Prochaska, J. Xavier; Werk, Jessica K.; Tumlinson, Jason; O'Meara, John M.; Bordoloi, Rongmon; Katz, Neal; Willmer, C. N. A.

    2015-12-01

    To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium, we have conducted a blind survey for C iv absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope Cosmic Origins Spectrograph. We have identified 42 absorbers at z critical density of the universe (ΩC iv = 10.0 ± 1.5 × 10-8) from z ˜ 1.5 to the present epoch, consistent with predictions from cosmological hydrodynamical simulations. Furthermore, the data support a functional form for the column density distribution function that deviates from a single power law, also consistent with independent theoretical predictions. As the data also probe heavy element ions in addition to C iv at the same redshifts, we identify, measure, and search for correlations between column densities of these species where components appear to be aligned in velocity. Among these ion-ion correlations, we find evidence for tight correlations between C ii and Si ii, C ii and Si iii, and C iv and Si iv, suggesting that these pairs of species arise in similar ionization conditions. However, the evidence for correlations decreases as the difference in ionization potential increases. Finally, when controlling for observational bias, we find only marginal evidence for a correlation (86.8% likelihood) between the Doppler line width b(C iv) and column density N(C iv).

  7. Immobilized salen (N,N'-bis (salicylidene) ethylenediamine) as a complexing agent for on-line sorbent extraction/preconcentration and flow injection-flame atomic absorption spectrometry

    The microcolumn of salen I (N,N'-bis (salicylidene) ethylenediamine) immobilized on surfactant-coated alumina has been used for on-line preconcentration of copper and lead with a flow injection-flame atomic absorption spectrometry (FI-AAS). Various parameters affecting the deposition/elution processes in the FI-AAS system was optimized. Deposition of analytes was affected at pH of ∼9, and injection of nitric acid (250 μl 2 mol l-1) served to elute retained species to AAS. A good relative standard deviation of 4.5 and 3.8% at 30 μg l-1(n = 7), high enrichment factors of 100 and 75, and detection limits of 0.3, 2.6 μg l-1 (3S) for Cu(II) and Pb(II) were obtained, respectively. The method was applied to water samples, multivitamin tablet and standard reference alloys (C12E41 and C12X3500) and accuracy was assessed through recovery experiment and independent analysis by furnace AAS, or comparing the results with the accepted values

  8. SDSS J163459.82+204936.0: A Ringed Infrared-luminous Quasar with Outflows in Both Absorption and Emission Lines

    Liu, Wen-Juan; Zhou, Hong-Yan; Jiang, Ning; Wu, Xufen; Lyu, Jianwei; Shi, Xiheng; Shu, Xinwen; Jiang, Peng; Ji, Tuo; Wang, Jian-Guo; Wang, Shu-Fen; Sun, Luming

    2016-05-01

    SDSS J163459.82+204936.0 is a local (z = 0.1293) infrared-luminous quasar with L IR = 1011.91 {L}⊙ . We present a detailed multiwavelength study of both the host galaxy and the nucleus. The host galaxy, appearing as an early-type galaxy in the optical images and spectra, demonstrates violent, obscured star formation activities with SFR ≈ 140 {M}⊙ yr-1, estimated from either the polycyclic aromatic hydrocarbon emission or IR luminosity. The optical to NIR spectra exhibit a blueshifted narrow cuspy component in Hβ, He i λλ5876, 10830, and other emission lines consistently with an offset velocity of ≈900 {km} {{{s}}}-1, as well as additional blueshifting phenomena in high-ionization lines (e.g., a blueshifted broad component of He i λ10830 and the bulk blueshifting of [O iii]λ5007), while there exist blueshifted broad absorption lines (BALs) in Na i D and He i λλ3889, 10830, indicative of the active galactic nucleus outflows producing BALs and emission lines. Constrained mutually by the several BALs in the photoionization simulations with Cloudy, the physical properties of the absorption line outflow are derived as follows: density 104 dust enshrouding as depicted by the co-evolution scenario invoking galaxy merger (or violent interaction) and quasar feedback. Its proximity enables our further observational investigations in detail (or tests) of the co-evolution paradigm.

  9. Absorption Line Survey of H3+ toward the Galactic Center Sources II. Eight Infrared Sources within 30 pc of the Galactic Center

    Goto, Miwa; Nagata, T; Geballe, T R; McCall, B J; Indriolo, N; Suto, H; Henning, T; Morong, C P; Oka, Takeshi

    2008-01-01

    Infrared absorption lines of H3+, including the metastable R(3,3)l line, have been observed toward eight bright infrared sources associated with hot and massive stars located in and between the Galactic Center Cluster and the Quintuplet Cluster 30 pc to the east. The absorption lines with high velocity dispersion arise in the Galaxy's Central Molecular Zone (CMZ) as well as in foreground spiral arms. The temperature and density of the gas in the CMZ, as determined from the relative strengths of the H3+ lines, are T=200-300K and n=50-200cm^-3. The detection of high column densities of H3+ toward all eight stars implies that this warm and diffuse gaseous environment is widespread in the CMZ. The products of the ionization rate and path length for these sight lines are 1000 and 10 times higher than in dense and diffuse clouds in the Galactic disk, respectively, indicating that the ionization rate, zeta, is not less than 10^-15 s^-1 and that L is at least on the order of 50 pc. The warm and diffuse gas is an impo...

  10. Laser-based absorption spectroscopy as a technique for rapid in-line analysis of respired gas concentrations of O2 and CO2

    Cummings, Beth; Hamilton, Michelle L.; Ciaffoni, Luca; Pragnell, Timothy R.; Peverall, Rob; Ritchie, Grant A. D.; Hancock, Gus; Robbins, Peter A.

    2011-01-01

    The use of sidestream analyzers for respired gas analysis is almost universal. However, they are not ideal for measurements of respiratory gas exchange because the analyses are both temporally dissociated from measurements of respiratory flow and also not generally conducted under the same physical conditions. This study explores the possibility of constructing an all optical, fast response, in-line breath analyzer for oxygen and carbon dioxide. Using direct absorption spectroscopy with a dio...

  11. A Survey of Metal Lines at High Redshift. II. SDSS Absorption Line Studies—O VI Line Density, Space Density, and Gas Metallicity at z abs ~ 3.0

    Frank, S.; Mathur, S.; Pieri, M.; York, D. G.

    2010-09-01

    We have analyzed a large data set of O VI absorber candidates found in the spectra of 3702 Sloan Digital Sky Survey (SDSS) quasars, focusing on a subsample of 387 active galactic nuclei sight lines with an average S/N >=5.0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r >= 0.19 Å for the O VI 1032 Å component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density ΔN/Δz for redshifts z abs >= 2.8. With extensive Monte Carlo simulations, we quantify the losses of absorbers due to blending with the ubiquitous Lyα forest lines and estimate the success rate of retrieving each individual candidate as a function of its redshift, the emission redshift of the quasar, the strength of the absorber, and the measured signal-to-noise ratio (S/N) of the spectrum by modeling typical Lyman forest spectra. These correction factors allow us to derive the "incompleteness and S/N-corrected" redshift number densities of O VI absorbers: ΔN O VI,c /Δzc (2.8 4.0) = 8.4 ± 2.9. We can place a secure lower limit for the contribution of O VI to the closure mass density at the redshifts probed here: ΩO VI (2.8 = 1.9 × 10-8 h -1. We show that the strong lines we probe account for over 65% of the mass in the O VI absorbers; the weak absorbers, while dominant in line number density, do not contribute significantly to the mass density. Making a conservative assumption about the ionization fraction, {O VI}/{O}, and adopting the Anders & Grevesse solar abundance values, we derive the mean metallicity of the gas probed in our search: ζ(2.8 = 3.6 × 10-4 h, in good agreement with other studies. These results demonstrate that large spectroscopic data sets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution.

  12. Flow injection on-line dilution for zinc determination in human saliva with electrothermal atomic absorption spectrometry detection

    An automated method is described for the determination of zinc in human saliva by electrothermal atomic absorption spectrometry (ET AAS) after on-line dilution of samples with a significant reduction of sample consumption per analysis (1) which allowed the introduction of 10 μL of either solution in the diluent stream. To avoid unnecessary waste of samples, the TBSI1 also permitted the recirculation of the solutions to their respective autosampler cups. The downstream diluted solution fills a home made sampling arm assembly. The sequential deposition of 20 μL aliquots of samples or standards on the graphite tube platform was carried out by air displacement with a similar time based solenoid injector (TBSI2). The dilution procedure and the injection of solutions into the atomizer are computer controlled and synchronized with the operation of the temperature program. Samples or standards solutions were submitted to two drying steps (at 90 and 130 deg. C), followed by pyrolysis and atomization at 700 and 1700 deg. C, respectively. The aqueous calibration was linear up to 120.0 μg L-1 for diluted standard solutions/samples and its slope was similar (p > 0.05) to the standard addition curve, indicating lack of matrix effect. The precision tested by repeated analysis of real saliva samples was less than 3% and the detection limit (3σ) was of 0.35 μg L-1. To test the accuracy of the proposed procedure, recovery tests were performed, obtaining mean recovery of added zinc of 97.8 ± 1.3%. Furthermore, Zn values estimated by the procedure developed in this work were compared with those obtained by a standard addition flame-AAS method applied to 20 randomly selected saliva samples. No significant differences (p > 0.05) were obtained between the two methods. Zinc levels in saliva samples from 44 healthy volunteers, 15 male and 29 female, with ages between 20 and 51 years (mean 30.50 ± 9.14 years) were in the range 22-98 μg L-1 (mean of 55 ± 17 μg L-1), similar to some

  13. LiBr absorption systems integrated with high–efficiency IGSG plant

    Rokni, Masoud; Bellomare, Filippo

    2015-01-01

    vapor compression inverse cycles; waste heat from other systems can in fact be used as an efficient input instead of electrical energy. The opportunity to integrate Li-Br absorption systems with a high-efficiency energy plant was studied; rejected heat from a Municipal Solid Waste Gasification Plant......Over the last few years, the energy demand for cooling systems is increasing; different solutions in fact have been proposed in order to minimize the energetic and environmental impact of this trend. In this direction, absorption cooling systems are recognized as a valid alternative to traditional...... Integrated with Solid Oxide Fuel Cell and Gas Turbine, called IGSG (Integrated Gasification SOFC and GT), was in fact considered to feed absorption cooling units. Two different possible integrations of heat fluxes were investigated; variations of the most critical parameters have been studied and analyzed in...

  14. Project development and commercialization of on-line analysis systems

    A project team first in the Australian Atomic Energy Commission (AAEC) and since 1982 in CSIRO has developed many on-line analysis systems for the mineral and energy industries. The development of these projects has followed a common pattern of laboratory R and D, field trials, commercialisation and technology transfer. This successful pattern is illustrated using examples of the development of systems for the on-line analysis of mineral slurries, for determination of the ash content of coal on conveyors, and for determination of the flow rates of oil, water and gas in pipelines. The first two systems are licensed to Australian companies, Amdel Ltd and Mineral Control Instrumentation Ltd. Both systems are used by industry worldwide, and are the market leaders for radioisotope gauges in their application field. The third system, the multiphase flow meter, was licensed in 1997 to Kvaerner FSSL Ltd of Aberdeen. This meter has even greater potential than the other two systems for economic benefit from its used and for numbers of installations. The on-line analysis systems have been developed to increase the productivity of the Australian mineral and energy industries, and to provide economic benefit to Australia. The economic benefit sought is predominantly improved process control based on use of the instrument, rather than from its sale. Sales of instruments are significant, however, with about A$80 million from the analysis systems and their derivatives since the 1970s. Some of the issues associated with the development of the on-line analysis system are outlined

  15. On-line control system for a testing vacuum bed

    On-line control system (CS) designed for reduction of time for accelerator vacuum element (differential pumping-out units, vacuum chambers etc) technological pretreatment; for increase of application coefficient for stand resources; for development of measurement technique, recording and visualization of vacuum parameters and technological parameters of the main vacuum equipment; for standardization of verified vacuum multimicroprocessor system with CAMAC combined protocol

  16. Straight-Line: A nuclear material storage information management system

    Sandia National Laboratories is developing Straight-Line -- a pilot system to demonstrate comprehensive monitoring of nuclear material in storage. Straight-Line is an integrated system of sensors providing information that will enhance the safety, security, and international accountability of stored nuclear material. The goals of this effort are to: (1) Provide the right sensor information to the right user immediately. (2) Reduce the expenses, risks, and frequency of human inspection of the material. (3) Provide trustworthy data to international inspectors to minimize their need to make on site inspections. In pursuit of these goals, Straight-Line unites technology from Sandia's Authenticated Item Monitoring System (AIMS) and other programs to communicate the authenticated status of the monitored item back to central magazine receivers. Straight-Line, however, incorporates several important features not found in previous systems: (1) Information Security -- the ability to collect and safely disseminate both classified and unclassified sensor data to users on a need-to-know basis. (2) Integrate into a single system the monitoring needs of safety, security, and international accountability. (3) Incorporate the use of sensors providing analog or digital output. This paper will present the overall architecture and status of the Straight-Line project

  17. Social absorption capability, systems of innovation and manufactured export response to preferential trade incentives

    Na-Allah, Abdelrasaq; Muchie, Mammo

    2012-01-01

    the process is relegated to the background. This paper argues that social absorption capability of a beneficiary's economy as expressed in her incumbent systems of innovation is a crucial determinant of export performance response. The experience of Sub-Saharan African countries under the US African...... beneficiaries of the scheme is a function of the relative efficiency of her system of innovation....

  18. Parametric analysis of an irreversible proton exchange membrane fuel cell/absorption refrigerator hybrid system

    A hybrid system mainly consisting of a PEMFC (proton exchange membrane fuel cell) and an absorption refrigerator is proposed, where the PEMFC directly converts the chemical energy contained in the hydrogen into electrical and thermal energies, and the thermal energy is transferred to drive the bottoming absorption refrigerator for cooling purpose. By considering the existing irreversible losses in the hybrid system, the operating current density region of the PEMFC permits the absorption refrigerator to exert its function is determined and the analytical expressions for the equivalent power output and efficiency of the hybrid system under different operating conditions are specified. Numerical calculations show that the equivalent maximum power density and the corresponding efficiency of the hybrid system can be respectively increased by 5.3% and 6.8% compared to that of the stand-alone PEMFC. Comprehensive parametric analyses are conducted to reveal the effects of the internal irreversibility of the absorption refrigerator, operating current density, operating temperature and operating pressure of the PEMFC, and some integrated parameters related to the thermodynamic losses on the performance of the hybrid system. The model presented in the paper is more general than previous study, and the results for some special cases can be directly derived from this paper. - Highlights: • A CHP system composed of a PEMFC and an absorption refrigerator is proposed. • Current density region enables the absorption refrigerator to work is determined. • Multiple irreversible losses in the system are analytically characterized. • Maximum power density and corresponding efficiency can be increased by 5.3% and 6.8%. • Effects of some designing and operating parameters on the performance are discussed

  19. Systems, methods and apparatus for developing and maintaining evolving systems with software product lines

    Hinchey, Michael G. (Inventor); Rash, James L. (Inventor); Pena, Joaquin (Inventor)

    2011-01-01

    Systems, methods and apparatus are provided through which an evolutionary system is managed and viewed as a software product line. In some embodiments, the core architecture is a relatively unchanging part of the system, and each version of the system is viewed as a product from the product line. Each software product is generated from the core architecture with some agent-based additions. The result may be a multi-agent system software product line.

  20. The role of absorption cooling for reaching sustainable energy systems

    Lindmark, Susanne

    2005-01-01

    The energy consumption is continuous to increase around the world and with that follows the demand for sustainable solutions for future energy systems. With growing energy consumption from fossil based fuels the threat of global warming through release of CO2 to the atmosphere increases. The demand for cooling is also growing which would result in an increased consumption of electricity if the cooling demand was to be fulfilled by electrically driven cooling technology. A more sustainable sol...