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Sample records for seyfert galaxy ic

  1. Radio Jets Clearing the Way Through a Galaxy: Watching Feedback in Action in the Seyfert Galaxy IC 5063

    NARCIS (Netherlands)

    Morganti, R.; Oosterloo, T. A.; Oonk, J. B. R.; Frieswijk, W.; Tadhunter, C. N.

    2015-01-01

    High-resolution (0.5 arcsec) CO(2-1) observations performed with the Atacama Large Millimetre/submillimetre Array have been used to trace the kinematics of the molecular gas in the Seyfert 2 galaxy{IC 5063}. Although one of the most radio-loud Seyfert galaxy, IC 5063 is a relatively weak radio

  2. Radio Jets Clearing the Way Through a Galaxy: Watching Feedback in Action in the Seyfert Galaxy IC 5063

    Science.gov (United States)

    Morganti, R.; Oosterloo, T. A.; Oonk, J. B. R.; Frieswijk, W.; Tadhunter, C. N.

    2015-12-01

    High-resolution (0.5 arcsec) CO(2-1) observations performed with the Atacama Large Millimetre/submillimetre Array have been used to trace the kinematics of the molecular gas in the Seyfert 2 galaxy{IC 5063}. Although one of the most radio-loud Seyfert galaxy, IC 5063 is a relatively weak radio source (P1.4GHz=3 ×1023 W Hz-1). The data reveal that the kinematics of the gas is very complex. A fast outflow of molecular gas extends along the entire radio jet (˜ 1 kpc), with the highest outflow velocities about 0.5 kpc from the nucleus, at the location of the brighter hot-spot in the W lobe. All the observed characteristics can be described by a scenario of a radio plasma jet expanding into a clumpy medium, interacting directly with the clouds and inflating a cocoon that drives a lateral outflow into the interstellar medium. This suggests that most of the observed cold molecular outflow is due to fast cooling of the gas after the passage of a shock and that it is the end product of the cooling process.

  3. The Seyfert galaxy population

    International Nuclear Information System (INIS)

    Meurs, E.

    1982-01-01

    A large sample of Seyfert galaxies, many of which are Markarian galaxies, has been observed with the WSRT in lambda 21 cm continuum radiation. The results are presented, and the number of radio detected Seyferts has now increased considerably. A number of accurate optical positions are given that were needed to identify radio sources with the Seyfert galaxies observed. Optical and radio luminosity functions of Seyfert galaxies are derived. The results are compared with such functions for other categories of objects that may be related to these galaxies. The discussions focus on the possible connections between normal galaxies, Seyferts, and optically selected quasars. Three investigations are reported on individual objects that are related to Seyfert galaxies. WSRT observations of four bright, optically selected quasars are presented. The identification of an X-ray discovered BL Lacertae object is discussed. Its radio emission is on a much lower level than for other BL Lacs. Perhaps it is a radio-quiet object in this class, suggesting a comparable difference in radio emission for BL Lacs as is known for quasars. Photo-electric photometry for the Seyfert galaxy NGC 1566 is reported. Besides a monitoring programme, multi-aperture photometry is described. (Auth.)

  4. FE K EMISSION AND ABSORPTION FEATURES IN THE XMM-EPIC SPECTRUM OF THE SEYFERT GALAXY IC 4329A

    Science.gov (United States)

    Markowitz, A.; Reeves, J. N.; Braito, V.

    2001-01-01

    We present a re-analysis of the XMM-Newton long-look of the X-ray bright Seyfert galaxy IC 4329a. The Fe K bandpass is dominated by two peaks, consistent with emission from neutral or near-neutral Fe Ka and KP. A relativistic diskline model whereby both peaks are the result of one doubly-peaked diskline profile is found to be a poor description of the data. Models using two relativistic disklines are found to describe the emission profile well. A low-inclination, moderately-relativistic dual-diskline model is possible if the contribution from narrow components, due to distant material, is small or absent. A high-inclination, moderately relativistic profile for each peak is possible if there are roughly equal contributions from both the broad and narrow components. Upper limits on Fe XXV and Fe XXVI emission and absorption at the systemic velocity of IC 4329a are obtained. We also present the results of RXTE monitoring of this source obtained so far; the combined XMM-Newton and RXTE data sets allow us to explore the time-resolved spectral behavior of this source on time scales ranging from hours to 2 years. We find no strong evidence for variability of the Fe Ka emission line on any time scale probed, likely due to the minimal level of continuum variability. We detect a narrow absorption line, at a energy of 7.68 keV in the rest frame of the source; its significance has been confirmed using Monte Carlo simulations. This feature is most likely due to absorption from Fe XXVI blueshifted to approximately 0.1c relative to the systemic velocity, making IC 4329a the lowest-redshift AGN known with a high-velocity, highly-ionized outflow component. As is often the case with similar outflows seen in high-luminosity quasars, the estimated mass outflow rate is larger than the inflow accretion rate, signaling that the outflow represents a substantial portion of the total energy budget of the AGN. The outflow could arise from a radiatively-driven disk wind, or it may be in the

  5. Connection between Seyfert galaxies and clusters

    International Nuclear Information System (INIS)

    Petrosyan, A.R.

    1988-01-01

    To identify Seyfert galaxies that are members of clusters, the sample of known Seyfert galaxies (464 objects) is tested against the Zwicky, Abell, and southern clusters. On the basis of the criteria adopted in the paper, 67 Seyfert galaxies are selected as probable members of Zwicky clusters, 15 as members of Abell clusters, and 18 as members of southern clusters. Lists of these objects are given

  6. Optical emission line spectra of Seyfert galaxies and radio galaxies

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1978-01-01

    Many radio galaxies have strong emission lines in their optical spectra, similar to the emission lines in the spectra of Seyfert galaxies. The range of ionization extends from [O I] and [N I] through [Ne V] and [Fe VII] to [Fe X]. The emission-line spectra of radio galaxies divide into two types, narrow-line radio galaxies whose spectra are indistinguishable from Seyfert 2 galaxies, and broad-line radio galaxies whose spectra are similar to Seyfert 1 galaxies. However on the average the broad-line radio galaxies have steeper Balmer decrements, stronger [O III] and weaker Fe II emission than the Seyfert 1 galaxies, though at least one Seyfert 1 galaxy not known to be a radio source has a spectrum very similar to typical broad-line radio galaxies. Intermediate-type Seyfert galaxies exist that show various mixtures of the Seyfert 1 and Seyfert 2 properties, and the narrow-line or Seyfert 2 property seems to be strongly correlated with radio emission. (Auth.)

  7. Demographics of Starbursts in Nearby Seyfert Galaxies

    Science.gov (United States)

    Schinnerer, E.; Colbert, E.; Armus, L.; Scoville, N. Z.; Heckman, T.

    2002-12-01

    We investigate the frequency of circumnuclear starbursts in Seyfert galaxies using medium-resolution H and K band spectroscopy. An unbiased sample of ~20 nearby Seyfert galaxies was observed at the KeckII telescope with an average seeing of ~0.7''. Preliminary analysis shows strong stellar absorption lines for most galaxies in our sample. Comparison of stellar equivalent widths in the H and K band will allow us to determine the average age of the dominating stellar population. Evidence for an age trend with Seyfert type would provide a strong hint toward a starburst/AGN connection.

  8. Spectrophotometry of the Seyfert galaxy NGC 4593

    International Nuclear Information System (INIS)

    MacAlpine, G.M.; Williams, G.A.; Lewis, D.W.

    1979-01-01

    Spectrophotometry of the bright class 1 Seyfert galaxy NGC 4593 is presented. The emission-line characteristics are briefly discussed and compared with those of other Seyfert galaxies. The measured hydrogen Balmer-line ratios are reasonably consistent with expected recombination values, and the emission intensities of Fe II, He I 5876, and forbidden O III 4363 relative to other lines are stronger than average in NGC 4593

  9. Spectroscopy of the galaxy components of N and Seyfert galaxies

    International Nuclear Information System (INIS)

    Boroson, T.A.; Oke, J.B.; Palomar Observatory, Pasadena, CA)

    1987-01-01

    Nuclear and off-nuclear spectra of nine active galaxies are presented. The sample consists of four Seyfert galaxies, two N galaxies, one Seyfert radio galaxy, and one liner/Seyfert 2 galaxy. All of the objects show continuum emission off the nucleus. Four clearly show absorption features from a stellar population. Velocities have been measured for the off-nuclear emission and absorption lines. In the case of I Zw 1, the absorption-line velocities are inconsistent with 21-cm H I measurements of this object. 26 references

  10. Irregular Dwarf Galaxy IC 1613

    Science.gov (United States)

    2005-01-01

    Ultraviolet image (left) and visual image (right) of the irregular dwarf galaxy IC 1613. Low surface brightness galaxies, such as IC 1613, are more easily detected in the ultraviolet because of the low background levels compared to visual wavelengths.

  11. Extended Narrow-Line Region in Seyfert Galaxies

    Directory of Open Access Journals (Sweden)

    Enrico Congiu

    2017-10-01

    Full Text Available We present our recent results about the extended narrow-line region (ENLR of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212 obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1 galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a the contribution of shocks in ionizing the high velocity gas, (b the complex kinematics showed by the profile of the emission lines, (c the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  12. Extended Narrow-Line Region in Seyfert Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Congiu, Enrico [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Contini, Marcella [School of Physics and Astronomy, Tel Aviv University, Tel Aviv (Israel); Ciroi, Stefano; Cracco, Valentina [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Di Mille, Francesco [Las Campanas Observatory, La Serena (Chile); Berton, Marco [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero, E-mail: enrico.congiu@phd.unipd.it [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy)

    2017-10-24

    We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a) the contribution of shocks in ionizing the high velocity gas, (b) the complex kinematics showed by the profile of the emission lines, (c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  13. Extended Narrow-Line Region in Seyfert Galaxies

    International Nuclear Information System (INIS)

    Congiu, Enrico; Contini, Marcella; Ciroi, Stefano; Cracco, Valentina; Di Mille, Francesco; Berton, Marco; Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero

    2017-01-01

    We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a) the contribution of shocks in ionizing the high velocity gas, (b) the complex kinematics showed by the profile of the emission lines, (c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  14. Large-Scale Outflows in Seyfert Galaxies

    Science.gov (United States)

    Colbert, E. J. M.; Baum, S. A.

    1995-12-01

    \\catcode`\\@=11 \\ialign{m @th#1hfil ##hfil \\crcr#2\\crcr\\sim\\crcr}}} \\catcode`\\@=12 Highly collimated outflows extend out to Mpc scales in many radio-loud active galaxies. In Seyfert galaxies, which are radio-quiet, the outflows extend out to kpc scales and do not appear to be as highly collimated. In order to study the nature of large-scale (>~1 kpc) outflows in Seyferts, we have conducted optical, radio and X-ray surveys of a distance-limited sample of 22 edge-on Seyfert galaxies. Results of the optical emission-line imaging and spectroscopic survey imply that large-scale outflows are present in >~{{1} /{4}} of all Seyferts. The radio (VLA) and X-ray (ROSAT) surveys show that large-scale radio and X-ray emission is present at about the same frequency. Kinetic luminosities of the outflows in Seyferts are comparable to those in starburst-driven superwinds. Large-scale radio sources in Seyferts appear diffuse, but do not resemble radio halos found in some edge-on starburst galaxies (e.g. M82). We discuss the feasibility of the outflows being powered by the active nucleus (e.g. a jet) or a circumnuclear starburst.

  15. Bright emission lines in new Seyfert galaxies

    International Nuclear Information System (INIS)

    Afanasev, V.L.; Denisiuk, E.K.; Lipovetskii, V.A.; Shapovalova, A.I.

    1983-01-01

    Observational data are given on bright emission lines (H-alpha, H-beta, and forbidden N II, S II, and O III) for 14 recently discovered Seyfert galaxies. The investigated objects can be divided into three groups, which correspond approximately to the first (5 objects), the intermediate (4 objects), and the second (4 objects) Seyfert types. Attention is drawn to the properties of the galaxy Markaryan 1018, which has features of both the first and the second type and is distinguished by the weakness of its emission lines, which is probably due to a gas deficit. 7 references

  16. The Occurence of Nuclear Starbursts in Seyfert 1 Galaxies

    Science.gov (United States)

    Schinnerer, E.; Colbert, E.; Armus, L.; Scoville, N. Z.

    2001-05-01

    Medium resolution H and K band spectra with high angular reesolution were obtained for a small sample of nearby Seyfert galaxies using NIRSPEC at the Keck telescope. Recent studies with medium resolution have found evidence for a lack of powerful starbursts in Seyfert1 galaxies. Differences between the two Seyfert types might provide a challenge for the unified scheme proposed for Seyfert galaxies. A preliminary analysis indicates that most of the Seyfert1 galaxies do indeed show signs of circumnuclar star formation. Detailed modelling using population synthesis in conjunction with NIR spectral synthesis will allow to estimate the age, star formation history and mass of these stellar population.

  17. Line profile variations in selected Seyfert galaxies

    International Nuclear Information System (INIS)

    Kollatschny, W; Zetzl, M; Ulbrich, K

    2010-01-01

    Continua as well as the broad emission lines in Seyfert 1 galaxies vary in different galaxies with different amplitudes on typical timescales of days to years. We present the results of two independent variability campaigns taken with the Hobby-Eberly Telescope. We studied in detail the integrated line and continuum variations in the optical spectra of the narrow-line Seyfert galaxy Mrk 110 and the very broad-line Seyfert galaxy Mrk 926. The broad-line emitting region in Mrk 110 has radii of four to 33 light-days as a function of the ionization degree of the emission lines. The line-profile variations are matched by Keplerian disk models with some accretion disk wind. The broad-line region in Mrk 926 is very small showing an extension of two to three light-days only. We could detect a structure in the rms line-profiles as well as in the response of the line profile segments of Mrk 926 indicating the BLR is structured.

  18. Broad line regions in Seyfert-1 galaxies

    International Nuclear Information System (INIS)

    Groningen, E. van.

    1984-01-01

    To reproduce observed emission profiles of Seyfert galaxies, rotation in an accretion disk has been proposed. In this thesis, the profiles emitted by such an accretion disk are investigated. Detailed comparison with the observed profiles yields that a considerable fraction can be fitted with a power-law function, as predicted by the model. The author analyzes a series of high quality spectra of Seyfert galaxies, obtained with the 2.5m telescope at Las Campanas. He presents detailed analyses of two objects: Mkn335 and Akn120. In both cases, strong evidence is presented for the presence of two separate broad line zones. These zones are identified with an accretion disk and an outflowing wind. The disk contains gas with very high densities and emits predominantly the lower ionization lines. He reports on the discovery of very broad wings beneath the strong forbidden line 5007. (Auth.)

  19. An evolutionary link between Seyfert I and II galaxies

    International Nuclear Information System (INIS)

    Penston, M.V.; Perez, E.

    1984-01-01

    First spectra from the newly sited Isaac Newton Telescope show NGC 4151 and 3C 390.3 to have taken on a classification very close to Seyfert II. It is proposed that Seyfert II galaxies are Seyfert Is in which the continuum source is temporarily off. (author)

  20. A new southern Seyfert 1 galaxy

    CERN Document Server

    West, R M; Danks, A C

    1978-01-01

    ESO 140-G43 (Fairall-51) is confirmed as a 14/sup m/ type 1 Seyfert galaxy at V/sub 0/=4150 km s/sup -1/. M/sub V/=-20.8; largest diameter 40 kpc (H/sub 0/=55 km s/sup -1/ Mpc/sup -1/). It has two open spiral arms. R.A.=18/sup h/40/sup m/.2; Decl.=-62 degrees 25' (1950). (8 refs).

  1. Properties of Narrow line Seyfert 1 galaxies

    Science.gov (United States)

    Rakshit, Suvendu; Stalin, Chelliah Subramonian; Chand, Hum; Zhang, Xue-Guang

    2018-04-01

    Narrow line Seyfert 1 (NLSy1) galaxies constitute a class of active galactic nuclei characterized by the full width at half maximum (FWHM) of the Hα broad emission line 10 pixel-1. A strong correlation between the Hα and Hα emission lines is found both in the FWHM and flux. The nuclear continuum luminosity is found to be strongly correlated with the luminosity of Hα, Hα and [O III] emission lines. The black hole mass in NLSy1 galaxies is lower compared to their broad line counterparts. Compared to BLSy1 galaxies, NLSy1 galaxies have a stronger FeII emission and a higher Eddington ratio that place them in the extreme upper right corner of the R4570 - λEdd diagram. The distribution of the radio-loudness parameter (R) in NLSy1 galaxies drops rapidly at R>10 compared to the BLSy1 galaxies that have powerful radio jets. The soft X-ray photon index in NLSy1 galaxies is on average higher (2.9 ± 0.9) than BLSy1 galaxies (2.4 ± 0.8). It is anti-correlated with the Hα width but correlated with the FeII strength. NLSy1 galaxies on average have a lower amplitude of optical variability compared to their broad lines counterparts. These results suggest Eddington ratio as the main parameter that drives optical variability in these sources.

  2. Optical variability of the Seyfert galaxy nuclei

    International Nuclear Information System (INIS)

    Lyutyj, V.M.

    1979-01-01

    The results of the UBV observations of compact Seyfert galaxies during 1968-78 are given. The full amplitude ΔB approximately 2sup(m) of the variability of the nucleus of 3C 120 is considerably larger than that of any other Seyfert galaxy. The minimum brightness of 3C 120 in 1978, B=16sup(m).25 was observed for the first time during the photometric history of the object since 1900. The time delay Δt < or approximately 70sup(d) of the variability of colour index U-B of the nucleus of 3C 120 relatively to that of B and B-V have been discovered. This time delay is interpreted as the variability of the Balmer continuum. The nucleus of 2 Zw 136 appears to show such a variability also. The location of 3C 120 and 2 Zw 136 on two-colour diagram corresponds to the combined colours of hot (05) and cold (K-M) stars, if the time delay of U-B variability is taken into account. The colour indices of the nucleus of 3C 120 during the minimum of 1978 (B=16sup(m).25) correspond to those of the ring between the 7''-30'' apertures. This indicates to a very small contributions of the variable source during the 1978 minimum

  3. VLA Observation of Seyfert Galaxy MRK 6

    Science.gov (United States)

    Xu, C.; Baum, S. A.; O'Dea, C.; Colbert, E. J. M.

    1997-12-01

    We have obtained deep radio observation of the Seyfert 1.5 galaxy Mrk6 with all VLA configurations at 6 and 20 cm. We confirm the existence of two pairs of diffuse low surface brightness radio lobes at different scales and orientations. The larger pair of lobes extend ( ~ 40" or 20 kpc) ~ 30(deg) NW-SE, and is evidence of starburst-driven superwind as suggested in Baum et. al (1993). The outer lobes are roughly perpendicular to a set of inner lobes which extend ( ~ 4" or 2 kpc) E-W and are in turn perpendicular to the inner jets imaged by Kukula et. al (1996). Both pairs of lobes appear to have shell-like structures, as implied by the observed anti-symmetric emission morphology which might be due to limb brightening as a result of increasing optical depth at the line of sight. The width of each structure is comparable to the length of the next smaller structure suggesting a "self-similar" (and possibly dynamical) relationship between these structures. These nested "bubble-like" structures with different orientations pose a challenge to the current paradigm of energy transport in Seyfert galaxies.

  4. Inclination effects on the recognition of Seyfert galaxies

    International Nuclear Information System (INIS)

    Keel, W.C.

    1980-01-01

    Axial ratios have been measured from images of 91 Seyfert galaxies thought to be disk systems, and their distribution as a function of axial ratio compared to that of field spirals similarly distributed in distance. There is a deficiency of nearly edge-on Seyfert 1 galaxies relative to the comparison sample. Examination of the visibility of nuclei in a sample of nearby spirals indicates that the effect is too large to be caused by absorption in the disks of normal spiral galaxies, while no absorption other than that expected from such disks is found in non-Seyfert Markarian spirals with bright, condensed nuclei

  5. The origin of coronal lines in Seyfert galaxies

    International Nuclear Information System (INIS)

    Korista, K.T.; Ferland, G.J.

    1989-01-01

    This paper examines the possibility that the coronal line region in Seyfert galaxies may be the result of an interstellar medium (ISM) exposed to, and subsequently photoionized by, a 'bare' Seyfert nucleus. It is shown that a 'generic' AGN continuum illuminating the warm-phase of the ISM of a spiral galaxy can produce the observed emission. In this picture the same UV-radiation cone that is responsible for the high-excitation extended narrow-line emission clouds observed out to 1-2 kpc or farther from the nuclei of some Seyfert galaxies also produces the coronal lines. Soft X-rays originating in the nucleus are Compton-scattered off the ISM, thus producing extended soft X-ray emission, as observed in NGC 4151. The results of the calculations show a basic insensitivity to the ISM density, which explains why similar coronal line spectra are found in many Seyfert galaxies of varying physical environments. 60 refs

  6. Infrared observations of Seyfert galaxies and quasars

    International Nuclear Information System (INIS)

    Neugebauer, G.

    1978-01-01

    The infrared energy distributions of the Seyfert galaxies apparently contain three components: a galactic stellar component, a thermal component from heated dust, plus a nonthermal component. The appearance of the infrared energy distribution depends on which component dominates. There is also a correlation observed between the infrared energy distribution and the Khachikian Weedman class. Preliminary data on bright quasars are given. The infrared energy distributions generally increase into the infrared with a power law slope of approximately 1. In detail they differ from power laws with a significant fraction emitting most of their energy near 3μm. No differences in radio loud and radio quiet are obvious from the infrared energy distributions. The variability of the quasars in the infrared is generally correlated with the variability in the visible, although significant exceptions have been observed. (Auth.)

  7. On the driver of relativistic effect strength in Seyfert galaxies

    Czech Academy of Sciences Publication Activity Database

    Guainazzi, M.; Bianchi, S.; de La Calle, I.; Dovčiak, Michal; Longinotti, A. L.

    2011-01-01

    Roč. 531, July (2011), A131/1-A131/13 ISSN 0004-6361 Institutional research plan: CEZ:AV0Z10030501 Keywords : accretion disks * relativistic processes * nuclei galaxies * Seyfert galaxy * X-rays Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

  8. Seyfert Galaxies: Radio Continuum Emission Properties and the ...

    Indian Academy of Sciences (India)

    sample of Seyfert galaxies in the framework of the unification scheme. Key words. Galaxies: ... 25/49 sub-fields. Self-calibration is used iteratively to improve the image quality. 4. ... Antonucci, R. R. J., Miller, J. S. 1985, Astrophys. J., 297, 621.

  9. The circumnuclear environment of nearby non-interacting Seyfert galaxies

    International Nuclear Information System (INIS)

    Pogge, R.W.

    1988-01-01

    An investigation into the physical conditions prevailing in the regions immediately surrounding the active nuclei in 20 nearby, non-interacting Seyfert galaxies is reported. CCD interference-band images isolating the bright emission lines of Hα + [N II] λλ6548, 6583 and [O III] λ5007 have been obtained to search for spatially extended circumnuclear emission regions. Long-slit, low resolution spectrophotometry of interesting cases was used to probe the ionization state of the extended emission regions. For comparison, a CCD Hα + [N II] interference-band imaging survey of a statistically significant sample of 91 bright non-Seyfert spiral galaxies meeting the same non-interaction criteria has been carried out. Only three out of nine Seyfert 1s have spatially extended ionized gas regions compared with eight out of eleven Seyfert 2s. Enhanced circumnuclear star formation is uncommon to both Seyfert 1s and 2s. Extended emission in Seyfert 1s has essentially the same morphology in both Hα + [N II] and [O III] emission. In the Seyfert 2s, the Hα + [N II] and [O III] images show different extended emission morphologies. The [O III] emission regions appear as either one- or two-sided structures, four of which are resolved into two distinct cones of high-ionization gas emanating from the active nucleus. The morphology and ionization of these regions suggest collimation of the nuclear ionizing radiation field. The 91 non-interacting non-Seyfert spiral galaxies exhibit a rich variety of nuclear and circumnuclear emission-line structures ranging from no emission detected to bright stellar nuclei with complicated circumnuclear emission regions extending for many kiloparsecs

  10. The group environment of Seyfert galaxies. II. Spectrophotometry of galaxies in groups

    International Nuclear Information System (INIS)

    Fricke, K.J.; Kollatschny, W.

    1989-01-01

    Medium-resolution spectrophotometric data of 104 galaxies have been obtained. These galaxies are members of 22 loose groups of < 1 Mpc size. Thirteen of these groups contain Seyfert galaxies. In this paper we present calibrated emission-line data and absolute optical spectra of the individual galaxies as well as plates of each group

  11. H α IMAGING OF NEARBY SEYFERT HOST GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Theios, Rachel L.; Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90095 (United States); Ross, Nathaniel R., E-mail: rtheios@astro.caltech.edu [Raytheon Space and Airborne Systems, 2000 E El Segundo Boulevard, El Segundo, CA 90245 (United States)

    2016-05-01

    We used narrowband (Δ λ = 70 Å) interference filters with the CCD imaging camera on the Nickel 1.0 m telescope at Lick Observatory to observe 31 nearby ( z < 0.03) Seyfert galaxies in the 12 μ m active galaxy sample. We obtained pure emission-line images of each galaxy, which reach down to a flux limit of 7.3 × 10{sup −15} erg cm{sup −2} s{sup −1} arcsec{sup −2}, and corrected these images for [N ii] emission and extinction. We separated the H α emission line of the “nucleus” (central 100–1000 pc) from that of the host galaxy. The extended H α emission is expected to be powered by newly formed hot stars, and indeed correlates well with other indicators of current star formation rates (SFRs) in these galaxies: extended 7.7 μ m polycyclic aromatic hydrocarbon, total far-infrared, and radio luminosity. Relative to what would be expected from recent star formation, there is a 0.8 dex excess of radio emission in our Seyfert galaxies. The H α luminosity we measured in the centers of our galaxies is dominated by the active galactic nucleus (AGN), and is linearly correlated with the hard X-ray luminosity. There is, however, an upward offset of 1 dex in this correlation for the Seyfert 1s, because their nuclear H α emission includes a strong additional contribution from the broad-line region. We found a correlation between SFR and AGN luminosity. In spite of selection effects, we concluded that the absence of bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly significant. Finally, we used our measured spatial distributions of H α emission to determine what these Seyfert galaxies would look like when observed through fixed apertures (e.g., a spectroscopic fiber) at high redshifts. We found that although all of these Seyfert galaxies would be detectable emission-line galaxies at any redshift, most of them would appear to be dominated by (>67%) their H ii region emission. Only the most luminous AGNs (log( L {sub Hα}/erg s

  12. Narrow-Line Seyfert 1 Galaxies

    OpenAIRE

    Komossa, S.

    2007-01-01

    Presento una revisión breve de las propiedades conocidas de las galaxias Seyfert 1 con líneas angostas (NLS1) en todo el espectro electromagnético y de los modelos propuestos para explicarlas. Sus propiedades de continuo y de emisión de líneas manifiestan una forma extrema de la actividad Seyfert. Las galaxias NLS1 en sí pueden ofrecer pistas importantes para discernir los parámetros que impulsan la actividad nuclear. Sus tasas de acreción altas y cercanas a la tasa de Eddington proveen...

  13. An optical and near-infrared polarization survey of Seyfert and broad-line radio galaxies. Pt. 2

    International Nuclear Information System (INIS)

    Brindle, C.; Hough, J.H.; Bailey, J.A.; Axon, D.J.; Ward, M.J.; McLean, I.S.

    1990-01-01

    We discuss the wavelength dependence (0.44-2.2 μm) of polarization of the sample of 71 Seyfert and three broad-line radio galaxies presented in a previous paper. For four galaxies, 3A 0557-383, Fairall 51, IC 4392A and NGC 3783, we also present spectropolarimetry covering the wavelength range of 0.4-0.6 μm. (author)

  14. Quasars, Seyfert galaxies and active galactic nuclei

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1987-01-01

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

  15. Optical polarization position angle versus radio structure axis in Seyfert galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Antonucci, R R.J. [National Radio Astronomy Observatory, Charlottesville, VA (USA)

    1983-05-12

    The hypothesis that there are two polarization classes of Seyfert galaxies, analogous to the perpendicular and parallel radio galaxy groups, is investigated by examining optical polarimetry data. In the sample considered it is shown that all the Seyfert 1 galaxies have roughly parallel polarization while all the Seyfert 2 galaxies have roughly perpendicular polarizations. These alignment effects can be interpreted as being due to thin and thick scattering disks, respectively, surrounding the continuum sources. This would represent a fundamental difference between the two types of Seyfert galaxies.

  16. Radio properties of type 1.8 and 1.9 Seyfert galaxies

    International Nuclear Information System (INIS)

    Ulvestad, J.S.

    1986-01-01

    A number of type 1.8 and 1.9 Seyfert galaxies have been observed at the VLA in order to compare their properties with those of the other types of Seyfert galaxy. The observed types have radio luminosities in the range of 10 to the 39th-40.5th args/s, with the median near 10 to the 40th ergs/s. Most of these galaxies have radio sources with diameters of about 500 pc or less. The ratio of radio luminosity to featureless optical continuum luminosity in the Seyfert 1.8/12.9 galaxies and Seyfert 1.2/1.5 galaxies is intermediate between the values for Seyfert 1 and Seyfert 2 galaxies. The infrared-to-radio ratio decreases along the sequence from Seyfert 1 galaxies, through intermediate Seyfert galaxies, to Seyfert 2 galaxies. This systematic statistical difference in the ratio of two aspect-independent quantities implies that the differences among the Seyfert classes cannot be attributed solely to differences in viewing angle. 39 references

  17. Infrared studies of Seyfert galaxies and of the irregular galaxy M82

    International Nuclear Information System (INIS)

    Rodriguez Espinosa, J.M.

    1985-01-01

    Middle and far infrared studies of the irregular galaxy M82 and of Seyfert galaxies are presented. M 82 was observed spectrophotometrically from 8 to 13 microns at 6 different positions selected across its 10μm emitting region. The observations show that the mid-IR emitting region is fairly homogeneous and that similar physical processes are responsible for the emission observed throughout the central region of M82. A model is proposed to explain the 8 to 13μm spectrum of M82. A model accumulates 10 5 orion units in the central region of M82. The proposed model explains satisfactorily most of the observed properties of M82 from x-ray to radio wavelengths. It is also suggested that a similar model may be applied to other active nuclei, like the emission line galaxy NGC 1614 and the classical Seyfert 1 galaxy NGC 7469. For Seyfert galaxies, the dat analyzed are drawn from the recently released IRAS catalog. It is found that Seyfert galaxies are strong far infrared sources but, unlike the near and mid-IR emission from these sources, the far-IR emission does not appear to be produced by the active nucleus. Rather it is shown that the observed far-IR properties of Seyfert galaxies are consistent with their far-IR emission being produced in intense episodes of star formation taking place in or near the central regions of these galaxies

  18. Multiwavelength Observations of the Dwarf Seyfert 1 Galaxy POX 52

    Science.gov (United States)

    Thornton, Carol E.; Barth, A. J.; Ho, L. C.; Rutledge, R. E.; Greene, J. E.

    2006-12-01

    POX 52 is an unusual narrow-line Seyfert 1 galaxy, having an estimated black hole mass of order 105 solar masses and a dwarf host galaxy with an absolute magnitude of only MV = -17.6, which gives us a unique opportunity to study black hole-bulge relations in the low-mass regime. We present new observations from a multiwavelength campaign to study its active nucleus and host galaxy. The data include observations from the Chandra and XMM-Newton Observatories, the Hubble Space Telescope, and the Very Large Array. Chandra data show a highly variable point source with a 2.0 10.0 keV luminosity of 0.7 * 1042 ergs/s. We will also describe the X-ray spectral shape, the structure of the host galaxy as determined from GALFIT modeling of the HST ACS/HRC images, and the spectral energy distribution of the active nucleus.

  19. DISCOVERY OF RELATIVISTIC OUTFLOW IN THE SEYFERT GALAXY Ark 564

    International Nuclear Information System (INIS)

    Gupta, A.; Mathur, S.; Krongold, Y.; Nicastro, F.

    2013-01-01

    We present Chandra High Energy Transmission Grating Spectra of the narrow-line Seyfert-1 galaxy Ark 564. The spectrum shows numerous absorption lines which are well modeled with low-velocity outflow components usually observed in Seyfert galaxies. There are, however, some residual absorption lines which are not accounted for by low-velocity outflows. Here, we present identifications of the strongest lines as Kα transitions of O VII (two lines) and O VI at outflow velocities of ∼0.1c. These lines are detected at 6.9σ, 6.2σ, and 4.7σ, respectively, and cannot be due to chance statistical fluctuations. Photoionization models with ultra-high velocity components improve the spectral fit significantly, providing further support for the presence of relativistic outflow in this source. Without knowing the location of the absorber, its mass and energy outflow rates cannot be well constrained; we find E-dot (outflow)/L bol lower limit of ≥0.006% assuming a bi-conical wind geometry. This is the first time that absorption lines with ultra-high velocities are unambiguously detected in the soft X-ray band. The presence of outflows with relativistic velocities in active galactic nuclei (AGNs) with Seyfert-type luminosities is hard to understand and provides valuable constraints to models of AGN outflows. Radiation pressure is unlikely to be the driving mechanism for such outflows and magnetohydrodynamic may be involved

  20. A millimeter-wave survey of CO emission in Seyfert galaxies

    International Nuclear Information System (INIS)

    Heckman, T.M.; Blitz, L.; Wilson, A.S.; Armus, L.; Miley, G.K.

    1989-01-01

    Emission in the 115 GHz 1-0 line of CO has been detected in 18 Seyfert galaxies in a sample of 43. The CO properties of 29 Seyferts in the Revised Shapley Ames Catalog (RSA) are compared with the CO properties of normal galaxies of the same Hubble type. These RSA type 2 Seyferts have an average ratio of CO-to-blue luminosity that is about twice as large as that of the normal galaxies, but the RSA type 1 Seyferts have normal CO luminosities. The RSA type 2 Seyfert galaxies have an unusually large average ratio of CO luminosity-to-H I mass compared to normal disk galaxies. The RSA type 2 Seyferts have an average far-IR luminosity that is about four times larger than a non-Seyfert comparison sample, while the RSA type 1 Seyferts are not significantly more luminous than the non-Seyferts. The result imply that the two classes of Seyferts are intrinsically different from one another and that one class cannot evolve into another in less than a few million years. 129 refs

  1. Einstein SSS+MPC observations of Seyfert type galaxies

    Science.gov (United States)

    Holt, S. S.; Turner, T. J.; Mushotzky, R. F.; Weaver, K.

    1989-01-01

    The X-ray spectra of 27 Seyfert galaxies measured with the Solid State Spectrometer (SSS) onboard the Einstein Observatory is investigated. This new investigation features the utilization of simultaneous data from the Monitor Proportional Counter (MPC) and automatic correction for systematic effects in the SSS. The new results are that the best-fit single power law indices agree with those previously reported, but that soft excesses are inferred for at least 20 percent of the measured spectra. The soft excesses are consistent with either an approximately 0.25 keV black body or Fe-L line emission.

  2. NICMOS POLARIMETRY OF 'POLAR-SCATTERED' SEYFERT 1 GALAXIES

    International Nuclear Information System (INIS)

    Batcheldor, D.; Robinson, A.; Axon, D. J.; Young, S.; Quinn, S.; Smith, J. E.; Hough, J.; Alexander, D. M.

    2011-01-01

    The nuclei of Seyfert 1 galaxies exhibit a range of optical polarization characteristics that can be understood in terms of two scattering regions producing orthogonal polarizations: an extended polar scattering region (PSR) and a compact equatorial scattering region (ESR), located within the circum-nuclear torus. Here we present NICMOS 2.0 μm imaging polarimetry of six 'polar-scattered' Seyfert 1 (S1) galaxies, in which the PSR dominates the optical polarization. The unresolved nucleus ( 2μm ) is consistent with the average for the optical spectrum(θ v ), implying that the nuclear polarization is dominated by polar scattering at both wavelengths. The same is probably true for NGC 3227. In both NGC 4593 and Mrk 766, there is a large difference between θ 2μm and θ v off-nucleus, where polar scattering is expected to dominate. This may be due to contamination by interstellar polarization in NGC 4593, but there is no clear explanation in the case of the strongly polarized Mrk 766. Lastly, in Mrk 1239, a large change (∼60 0 ) in θ 2 μ m between the nucleus and the annulus indicates that the unresolved nucleus and its immediate surroundings have different polarization states at 2 μm, which we attribute to the ESR and PSR, respectively. A further implication is that the source of the scattered 2 μm emission in the unresolved nucleus is the accretion disk, rather than torus hot dust emission.

  3. A Radio Study of the Seyfert Galaxy Markarian 6: Implications for Seyfert Life Cycles

    Science.gov (United States)

    Kharb, P.; O'Dea, C. P.; Baum, S. A.; Colbert, E. J. M.; Xu, C.

    2006-11-01

    We have carried out an extensive radio study with the Very Large Array on the Seyfert 1.5 galaxy Mrk 6 and imaged a spectacular radio structure in the source. The radio emission occurs on three different spatial scales: ~7.5 kpc bubbles, ~1.5 kpc bubbles lying nearly orthogonal to them, and a ~1 kpc radio jet lying orthogonal to the kiloparsec-scale bubble. To explain the complex morphology, we first consider a scenario in which the radio structures are the result of superwinds ejected by a nuclear starburst. However, recent Spitzer observations of Mrk 6 provide an upper limit to the star formation rate (SFR) of ~5.5 Msolar yr-1, an estimate much lower than the SFR of ~33 Msolar yr-1 derived assuming that the bubbles are a result of starburst winds energized by supernova explosions. Thus, a starburst alone cannot meet the energy requirements for the creation of the bubbles in Mrk 6. We then present an energetically plausible model wherein the bubbles are a result of energy deposited by the kiloparsec-scale jet as it plows into the interstellar medium. Finally, we consider a model in which the complex radio structure is a result of an episodically powered precessing jet that changes its orientation. This model is the most attractive as it can naturally explain the complex radio morphology and is consistent with the energetics, the spectral index, and the polarization structure. Radio emission in this scenario is a short-lived phenomenon in the lifetime of a Seyfert galaxy, which results from an accretion event.

  4. Free-Free Absorption on Parsec Scales in Seyfert Galaxies

    Science.gov (United States)

    Roy, A. L.; Ulvestad, J. S.; Wilson, A. S.; Colbert, E. J. M.; Mundell, C. G.; Wrobel, J. M.; Norris, R. P.; Falcke, H.; Krichbaum, T.

    Seyfert galaxies come in two main types (types 1 and 2) and the difference is probably due to obscuration of the nucleus by a torus of dense molecular material. The inner edge of the torus is expected to be ionized by optical and ultraviolet emission from the active nucleus, and will radiate direct thermal emission (e.g. NGC 1068) and will cause free-free absorption of nuclear radio components viewed through the torus (e.g. Mrk 231, Mrk 348, NGC 2639). However, the nuclear radio sources in Seyfert galaxies are weak compared to radio galaxies and quasars, demanding high sensitivity to study these effects. We have been making sensitive phase referenced VLBI observations at wavelengths between 21 and 2 cm where the free-free turnover is expected, looking for parsec-scale absorption and emission. We find that free-free absorption is common (e.g. in Mrk 348, Mrk 231, NGC 2639, NGC 1068) although compact jets are still visible, and the inferred density of the absorber agrees with the absorption columns inferred from X-ray spectra (Mrk 231, Mrk 348, NGC 2639). We find one-sided parsec-scale jets in Mrk 348 and Mrk 231, and we measure low jet speeds (typically £ 0.1 c). The one-sidedness probably is not due to Doppler boosting, but rather is probably free-free absorption. Plasma density required to produce the absorption is Ne 3 2 105 cm-3 assuming a path length of 0.1 pc, typical of that expected at the inner edge of the obscuring torus.

  5. INVESTIGATING THE CORE MORPHOLOGY-SEYFERT CLASS RELATIONSHIP WITH HUBBLE SPACE TELESCOPE ARCHIVAL IMAGES OF LOCAL SEYFERT GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Rutkowski, M. J.; Hegel, P. R.; Kim, Hwihyun; Windhorst, R. A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Tamura, Kazuyuki [Naruto University of Education, Nakashima, Takashima, Naruto-cho, Naruto-shi 772-8502 (Japan)

    2013-07-01

    The unified model of active galactic nuclei (AGNs) has provided a successful explanation for the observed diversity of AGNs in the local universe. However, recent analysis of multi-wavelength spectral and image data suggests that the unified model is only a partial theory of AGNs, and may need to be augmented to remain consistent with all observations. Recent studies using high spatial resolution ground- and space-based observations of local AGNs show that Seyfert class and the ''core'' (r {approx}< 1 kpc) host-galaxy morphology are correlated. Currently, this relationship has only been established qualitatively, by visual inspection of the core morphologies of low-redshift (z < 0.035) Seyfert host galaxies. We re-establish this empirical relationship in Hubble Space Telescope optical imaging by visual inspection of a catalog of 85 local (D < 63 Mpc) Seyfert galaxies. We also attempt to re-establish the core morphology-Seyfert class relationship using an automated, non-parametric technique that combines both existing classification parameter methods (the adapted CAS and G-M {sub 20}) and a new method which implements the Source Extractor software for feature detection in unsharp-mask images. This new method is designed explicitly to detect dust features in the images. We use our automated approach to classify the morphology of the AGN cores and determine that Sy2 galaxies visually appear, on average, to have more dust features than Sy1. With the exception of this ''dustiness'' however, we do not measure a strong correlation between the dust morphology and the Seyfert class of the host galaxy using quantitative techniques. We discuss the implications of these results in the context of the unified model.

  6. Is the cluster environment quenching the Seyfert activity in elliptical and spiral galaxies?

    Science.gov (United States)

    de Souza, R. S.; Dantas, M. L. L.; Krone-Martins, A.; Cameron, E.; Coelho, P.; Hattab, M. W.; de Val-Borro, M.; Hilbe, J. M.; Elliott, J.; Hagen, A.; COIN Collaboration

    2016-09-01

    We developed a hierarchical Bayesian model (HBM) to investigate how the presence of Seyfert activity relates to their environment, herein represented by the galaxy cluster mass, M200, and the normalized cluster centric distance, r/r200. We achieved this by constructing an unbiased sample of galaxies from the Sloan Digital Sky Survey, with morphological classifications provided by the Galaxy Zoo Project. A propensity score matching approach is introduced to control the effects of confounding variables: stellar mass, galaxy colour, and star formation rate. The connection between Seyfert-activity and environmental properties in the de-biased sample is modelled within an HBM framework using the so-called logistic regression technique, suitable for the analysis of binary data (e.g. whether or not a galaxy hosts an AGN). Unlike standard ordinary least square fitting methods, our methodology naturally allows modelling the probability of Seyfert-AGN activity in galaxies on their natural scale, I.e. as a binary variable. Furthermore, we demonstrate how an HBM can incorporate information of each particular galaxy morphological type in an unified framework. In elliptical galaxies our analysis indicates a strong correlation of Seyfert-AGN activity with r/r200, and a weaker correlation with the mass of the host cluster. In spiral galaxies these trends do not appear, suggesting that the link between Seyfert activity and the properties of spiral galaxies are independent of the environment.

  7. Reverberation mapping of the Seyfert 1 galaxy NGC 7469

    International Nuclear Information System (INIS)

    Peterson, B. M.; Grier, C. J.; Pogge, R. W.; De Rosa, G.; Denney, K. D.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C.; Horne, Keith; Bentz, M. C.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Minezaki, T.; Siverd, R. J.; Bord, D. J.

    2014-01-01

    A large reverberation-mapping study of the Seyfert 1 galaxy NGC 7469 has yielded emission-line lags for Hβ λ4861 and He II λ4686 and a central black hole mass measurement M BH ≈ 1 × 10 7 M ☉ , consistent with previous measurements. A very low level of variability during the monitoring campaign precluded meeting our original goal of recovering velocity-delay maps from the data, but with the new Hβ measurement, NGC 7469 is no longer an outlier in the relationship between the size of the Hβ-emitting broad-line region and the luminosity of the active galactic nucleus. It was necessary to detrend the continuum and Hβ and He II λ4686 line light curves and those from archival UV data for different time-series analysis methods to yield consistent results.

  8. Reverberation mapping of the Seyfert 1 galaxy NGC 7469

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, B. M.; Grier, C. J.; Pogge, R. W.; De Rosa, G.; Denney, K. D.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife KY16 9SS (United Kingdom); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, 25 Park Place, Suite 605, Atlanta, GA 30303 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 298409 (Russian Federation); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Minezaki, T. [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1, Osawa, Mitaka, 181-0015 Tokyo (Japan); Siverd, R. J. [Department of Physics and Astronomy, Vanderbilt University, 6301 Stevenson Center, Nashville, TN 37235 (United States); Bord, D. J., E-mail: peterson.12@osu.edu [Department of Natural Sciences, The University of Michigan—Dearborn, 4901 Evergreen Road, Dearborn, MI 48128 (United States); and others

    2014-11-10

    A large reverberation-mapping study of the Seyfert 1 galaxy NGC 7469 has yielded emission-line lags for Hβ λ4861 and He II λ4686 and a central black hole mass measurement M {sub BH} ≈ 1 × 10{sup 7} M {sub ☉}, consistent with previous measurements. A very low level of variability during the monitoring campaign precluded meeting our original goal of recovering velocity-delay maps from the data, but with the new Hβ measurement, NGC 7469 is no longer an outlier in the relationship between the size of the Hβ-emitting broad-line region and the luminosity of the active galactic nucleus. It was necessary to detrend the continuum and Hβ and He II λ4686 line light curves and those from archival UV data for different time-series analysis methods to yield consistent results.

  9. Some implications of excess soft X-ray emission from Seyfert 1 galaxies

    International Nuclear Information System (INIS)

    Fabian, A.C.; Guilbert, P.W.; Arnaud, K.A.; Shafer, R.A.; Tennant, A.F.; Ward, M.J.

    1986-01-01

    The X-ray spectrum of Seyfert 1 galaxies is characterized by a hard power-law spectrum. It is often postulated that this maintains a Compton-heated two-phase Broad-Line Region (BLR) around the central source. It is shown here that the strong excess soft X-ray emission observed in MKN 841 and other Seyfert galaxies invalidates this model if the BLR is spherically symmetric. Alternatives are proposed. (author)

  10. Interpretation of the X-ray variability of type 1 Seyfert galaxy nuclei and quasars

    International Nuclear Information System (INIS)

    Zentsova, A.S.

    1985-01-01

    The hypothesis is analyzed that the X-ray variability of type 1 Seyfert galaxies ad quasars causes the absorption of the central object X radiation by emission clouds. It is shown that this hypothesis can explain the characteristic time scale of the X-ray variability and its amplitude. It is indicated that systematic X-ray observations of Seyfert galaxies and quasars for the investigation of the physical conditions in the emission clouds are important

  11. The Frequency of Circumnuclear Starbursts in Seyfert Galaxies --- Testing the Starburst-AGN Connection

    Science.gov (United States)

    Schinnerer, E.; Colbert, E.; Armus, L.; Scoville, N. Z.; Heckman, T. M.

    We obtained sub-arcsecond medium resolution near-infrared spectra of a sample of nearby bright Seyfert galaxies (8 Seyfert 1s, 11 Seyfert 2s) using the KeckII telescope. The stellar absorption lines present in the spectra were used in conjunction with population synthesis models to determine the age of the circumnuclear stellar population. Initial analysis of a sub-sample of the Seyfert galaxies has provided no evidence for a connection between the age of the circumnuclear stellar population and the Seyfert type. The derived ages for the circumnuclear stellar population are in the range of 10 Myr to < 0.5 Gyr assuming an instantaneous starburst (using the STARBURST99 models).

  12. REVERBERATION MAPPING RESULTS FOR FIVE SEYFERT 1 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B.; Stanek, K. Z.; Salvo, C. Araya; Beatty, T. G.; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Denney, K. D. [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Minezaki, T. [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1, Osawa, Mitaka, 181-0015, Tokyo (Japan); Siverd, R. [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States); Bord, D. J. [Department of Natural Sciences, The University of Michigan-Dearborn, 4901 Evergreen Road, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); and others

    2012-08-10

    We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140 day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501, 3C 120, Mrk 6, and PG 2130+099, from which we have measured the time lag between variations in the 5100 A continuum and the H{beta} broad emission line. We then used these measurements to calculate the mass of the supermassive black hole at the center of each of these galaxies. Our new measurements substantially improve previous measurements of M{sub BH} and the size of the broad line-emitting region for four sources and add a measurement for one new object. Our new measurements are consistent with photoionization physics regulating the location of the broad line region in active galactic nuclei.

  13. REVERBERATION MAPPING RESULTS FOR FIVE SEYFERT 1 GALAXIES

    International Nuclear Information System (INIS)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B.; Stanek, K. Z.; Salvo, C. Araya; Beatty, T. G.; Bird, J. C.; Denney, K. D.; Bentz, M. C.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Minezaki, T.; Siverd, R.; Bord, D. J.; Che, X.

    2012-01-01

    We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140 day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501, 3C 120, Mrk 6, and PG 2130+099, from which we have measured the time lag between variations in the 5100 Å continuum and the Hβ broad emission line. We then used these measurements to calculate the mass of the supermassive black hole at the center of each of these galaxies. Our new measurements substantially improve previous measurements of M BH and the size of the broad line-emitting region for four sources and add a measurement for one new object. Our new measurements are consistent with photoionization physics regulating the location of the broad line region in active galactic nuclei.

  14. X-ray spectral variability of Seyfert 2 galaxies

    Science.gov (United States)

    Hernández-García, L.; Masegosa, J.; González-Martín, O.; Márquez, I.

    2015-07-01

    Context. Variability across the electromagnetic spectrum is a property of active galactic nuclei (AGN) that can help constrain the physical properties of these galaxies. Nonetheless, the way in which the changes happen and whether they occur in the same way in every AGN are still open questions. Aims: This is the third in a series of papers with the aim of studying the X-ray variability of different families of AGN. The main purpose of this work is to investigate the variability pattern(s) in a sample of optically selected Seyfert 2 galaxies. Methods: We use the 26 Seyfert 2s in the Véron-Cetty and Véron catalog with data available from Chandra and/or XMM-Newton public archives at different epochs, with timescales ranging from a few hours to years. All the spectra of the same source were simultaneously fitted, and we let different parameters vary in the model. Whenever possible, short-term variations from the analysis of the light curves and/or long-term UV flux variations were studied. We divided the sample into Compton-thick and Compton-thin candidates to account for the degree of obscuration. When transitions between Compton-thick and thin were obtained for different observations of the same source, we classified it as a changing-look candidate. Results: Short-term variability at X-rays was studied in ten cases, but variations are not found. From the 25 analyzed sources, 11 show long-term variations. Eight (out of 11) are Compton-thin, one (out of 12) is Compton-thick, and the two changing-look candidates are also variable. The main driver for the X-ray changes is related to the nuclear power (nine cases), while variations at soft energies or related to absorbers at hard X-rays are less common, and in many cases these variations are accompanied by variations in the nuclear continuum. At UV frequencies, only NGC 5194 (out of six sources) is variable, but the changes are not related to the nucleus. We report two changing-look candidates, MARK 273 and NGC 7319

  15. MULTI-WAVELENGTH PROBES OF OBSCURATION TOWARD THE NARROW-LINE REGION IN SEYFERT GALAXIES

    International Nuclear Information System (INIS)

    Kraemer, S. B.; Schmitt, H.R.; Crenshaw, D. M.; Melendez, M.; Turner, T.J.; Guainazzi, M.; Mushotzky, R.F.

    2011-01-01

    We present a study of reddening and absorption toward the narrow line regions (NLRs) in active galactic nuclei (AGNs) selected from the Revised Shapley-Ames, 12 μm, and Swift/Burst Alert Telescope samples. For the sources in host galaxies with inclinations of b/a > 0.5, we find that the mean ratio of [O III] λ5007, from ground-based observations, and [O IV] 28.59 μm, from Spitzer/Infrared Spectrograph observations, is a factor of two lower in Seyfert 2s than Seyfert 1s. The combination of low [O III]/[O IV] and [O III] λ4363/λ5007 ratios in Seyfert 2s suggests more extinction of emission from the NLR than in Seyfert 1s. Similar column densities of dusty gas, N H ∼ several x 10 21 cm -2 , can account for the suppression of both [O III] λ5007 and [O III] λ4363, as compared to those observed in Seyfert 1s. Also, we find that the X-ray line O VII λ22.1 A is weaker in Seyfert 2s, consistent with absorption by the same gas that reddens the optical emission. Using a Hubble Space Telescope/Space Telescope Imaging Spectrograph slitless spectrum of the Seyfert 1 galaxy NGC 4151, we estimate that only ∼30% of the [O III] λ5007 comes from within 30 pc of the central source, which is insufficient to account for the low [O III]/[O IV] ratios in Seyfert 2s. If Seyfert 2 galaxies have similar intrinsic [O III] spatial profiles, the external dusty gas must extend further out along the NLR, perhaps in the form of nuclear dust spirals that have been associated with fueling flows toward the AGN.

  16. 3D Studies of Neutral and Ionised Gas and Stars in Seyfert and Inactive Galaxies

    NARCIS (Netherlands)

    Mundell, C. G.; Dumas, G.; Schinnerer, E.; Nagar, N.; Wilcots, E.; Wilson, A. S.; Emsellem, E.; Ferruit, P.; Peletier, R. F.; De Zeeuw, P. T.; Haan, S.

    Abstract: We are conducting the first systematic 3D spectroscopic imaging survey to quantify the properties of the atomic gas (HI) in a distance-limited sample of 28 Seyfert galaxies and a sample of 28 inactive control galaxies with well-matched optical properties (the VHIKINGS survey). This study

  17. Soft X-ray Emission from Large-Scale Galactic Outflows in Seyfert Galaxies

    Science.gov (United States)

    Colbert, E. J. M.; Baum, S.; O'Dea, C.; Veilleux, S.

    1998-01-01

    Kiloparsec-scale soft X-ray nebulae extend along the galaxy minor axes in several Seyfert galaxies, including NGC 2992, NGC 4388 and NGC 5506. In these three galaxies, the extended X-ray emission observed in ROSAT HRI images has 0.2-2.4 keV X-ray luminosities of 0.4-3.5 x 10(40) erg s(-1) . The X-ray nebulae are roughly co-spatial with the large-scale radio emission, suggesting that both are produced by large-scale galactic outflows. Assuming pressure balance between the radio and X-ray plasmas, the X-ray filling factor is >~ 10(4) times as large as the radio plasma filling factor, suggesting that large-scale outflows in Seyfert galaxies are predominantly winds of thermal X-ray emitting gas. We favor an interpretation in which large-scale outflows originate as AGN-driven jets that entrain and heat gas on kpc scales as they make their way out of the galaxy. AGN- and starburst-driven winds are also possible explanations if the winds are oriented along the rotation axis of the galaxy disk. Since large-scale outflows are present in at least 50 percent of Seyfert galaxies, the soft X-ray emission from the outflowing gas may, in many cases, explain the ``soft excess" X-ray feature observed below 2 keV in X-ray spectra of many Seyfert 2 galaxies.

  18. MASS OUTFLOW IN THE SEYFERT 1 GALAXY NGC 5548

    International Nuclear Information System (INIS)

    Crenshaw, D. M.; Kraemer, S. B.; Schmitt, H. R.; Kaastra, J. S.; Arav, N.; Gabel, J. R.; Korista, K. T.

    2009-01-01

    We present a study of the intrinsic UV absorption and emission lines in an historically low-state spectrum of the Seyfert 1 galaxy NGC 5548, which we obtained in 2004 February at high spatial and spectral resolution with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. We isolate a component of emission with a width of 680 km s -1 that arises from an 'intermediate-line region' (ILR), similar to that we discovered in NGC 4151, at a distance of ∼1 pc from the central continuum source. From a detailed analysis of the five intrinsic absorption components in NGC 5548 and their behavior over a span of eight years, we present evidence that most of the UV absorbers only partially cover the ILR and do not cover an extended region of UV continuum emission, most likely from hot stars in the circumnuclear region. We also find that four of the UV absorbers are at much greater distances (greater than 70 pc) than the ILR, and none have sufficient N V or C IV column densities to be the ILR in absorption. At least a portion of the UV absorption component 3, at a radial velocity of -530 km s -1 , is likely responsible for most of the X-ray absorption, at a distance less than 7 pc from the central source. The fact that we see the ILR in absorption in NGC 4151 and not in NGC 5548 suggests that the ILR is located at a relatively large polar angle (∼45 deg.) with respect to the narrow-line region outflow axis.

  19. HE I triplet line emission in class 1 Seyfert galaxies

    International Nuclear Information System (INIS)

    Feldman, F.R.

    1979-01-01

    The equation of statistical equilibrium were solved for an 11-level helium atom, including all important radiative and collisional transitions and allowing for self-absorption from any level. Gas physical conditions considered are 5 x 10 8 cm -3 less than or equal to N less than or equal to 5 x 10 10 cm -3 , 5000 K less than or equal to T less than or equal to 20,000 K and a range of optical depth in the lambda 10830 line (10 less than or equal to tau(lambda 10830) less than or equal to 500) as a free parameter. For a photoionized, optically thick cloud, tau(lambda 10830) is shown to be nearly proportional to a measure of the ratio of photoionizing flux to cloud density (U 1 ), provided that photoionization from excited He 0 levels can be neglected. Calculated triplet line intensities as a function of tau(lambda 10830) are presented in graphical form, illustrating the significance of collisional excitation from 2 3 S and 2 3 P as well as self-absorption in lines terminating on 2 3 P. The possible importance of photoionization from the n = 2 levels by continuum and resonance-line radiation was investigated. This process may significantly influence triplet line strengths for small photoionizing-source/cloud separations (high U 1 ), unless most scattered hydrogen Lα and C IV lambda 1549 photons are destroyed by dust grains (or by some other mechanism). New spectrophotometric observations of 3C 120, Mrk 618, NGC 7469, and Mrk 335 are compared to the theoretical results. It appears that class 1 Seyfert galaxies with strong helium lines may be characterized by N approx. = 5 x 10 9 cm -3 , T approx. = 15,000 K and tau(lambda 10830) approx. = 100, assuming no photoionization from n = 2

  20. Fermi monitoring of radio-loud narrow-line Seyfert 1 galaxies

    International Nuclear Information System (INIS)

    Paliya, Vaidehi S.; Stalin, C. S.; Ravikumar, C. D.

    2015-01-01

    We present detailed analysis of the γ-ray flux variability and spectral properties of the five radio-loud narrow line Seyfert 1 (RL-NLSy1) galaxies, detected by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope, namely 1H 0323+342, SBS 0846+513, PMN J0948+0022, PKS 1502+036, and PKS 2004−447. The first three sources show significant flux variations, including the rapid variability of a few hours by 1H 0323+342. The average γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 shows deviation from a simple power-law (PL) behavior, whereas the PL model gives a better fit for the other three sources. The spectra of 1H 0323+342, SBS 0846+513, and PMN J0948+0022, which are in low, flaring, and moderately active states, respectively, show significant curvature. Such curvature in the γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 could be due to the emission region located inside the broad line region (BLR) where the primary mechanism of the γ-ray emission is inverse-Compton (IC) scattering of BLR photons occurring in the Klein–Nishina regime. The γ-ray emission of SBS 0846+513 is explained by IC scattering of dusty torus photons, which puts the emission region outside the BLR and thus under the Thomson regime. Therefore, the observed curvature of SBS 0846+513 could be intrinsic to the particle energy distribution. The presence of curvature in the γ-ray spectrum and flux variability amplitudes of some of the RL-NLSy1 galaxies suggests that these sources could be akin to low/moderate jet power flat spectrum radio quasars.

  1. Fermi monitoring of radio-loud narrow-line Seyfert 1 galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Paliya, Vaidehi S.; Stalin, C. S. [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore-560034 (India); Ravikumar, C. D., E-mail: vaidehi@iiap.res.in [Department of Physics, University of Calicut, Malappuram-673635 (India)

    2015-02-01

    We present detailed analysis of the γ-ray flux variability and spectral properties of the five radio-loud narrow line Seyfert 1 (RL-NLSy1) galaxies, detected by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope, namely 1H 0323+342, SBS 0846+513, PMN J0948+0022, PKS 1502+036, and PKS 2004−447. The first three sources show significant flux variations, including the rapid variability of a few hours by 1H 0323+342. The average γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 shows deviation from a simple power-law (PL) behavior, whereas the PL model gives a better fit for the other three sources. The spectra of 1H 0323+342, SBS 0846+513, and PMN J0948+0022, which are in low, flaring, and moderately active states, respectively, show significant curvature. Such curvature in the γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 could be due to the emission region located inside the broad line region (BLR) where the primary mechanism of the γ-ray emission is inverse-Compton (IC) scattering of BLR photons occurring in the Klein–Nishina regime. The γ-ray emission of SBS 0846+513 is explained by IC scattering of dusty torus photons, which puts the emission region outside the BLR and thus under the Thomson regime. Therefore, the observed curvature of SBS 0846+513 could be intrinsic to the particle energy distribution. The presence of curvature in the γ-ray spectrum and flux variability amplitudes of some of the RL-NLSy1 galaxies suggests that these sources could be akin to low/moderate jet power flat spectrum radio quasars.

  2. Far-ultraviolet and optical spectrophotometry of X-ray selected Seyfert galaxies

    International Nuclear Information System (INIS)

    Clarke, J.T.; Bowyer, S.; Grewing, M.; California Univ., Berkeley; Tuebingen Universitaet, West Germany)

    1986-01-01

    Five X-ray selected Seyfert galaxies were examined via near-simultaneous far-ultraviolet and optical spectrophotometry in an effort to test models for excitation of emission lines by X-ray and ultraviolet continuum photoionization. The observed Ly-alpha/H-beta ratio in the present sample averages 22, with an increase found toward the high-velocity wings of the H lines in the spectrum of at least one of the Seyfert I nuclei. It is suggested that Seyfert galaxies with the most high-velocity gas exhibit the highest Ly-alpha/H-beta ratios at all velocities in the line profiles, and that sometimes this ratio may be highest for the highest velocity material in the broad-line clouds. Since broad-lined objects are least affected by Ly-alpha trapping effects, they have Ly-alpha/H-beta ratios much closer to those predicted by early photoionization calculations. 21 references

  3. POX 52: A Dwarf Seyfert 1 Galaxy with an Intermediate-Mass Black Hole

    Science.gov (United States)

    Barth, Aaron J.; Ho, Luis C.; Rutledge, Robert E.; Sargent, Wallace L. W.

    2004-05-01

    We describe new optical images and spectra of POX 52, a dwarf galaxy with an active nucleus that was originally detected in the POX objective-prism survey. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an emission-line spectrum very similar to that of the dwarf Seyfert 1 galaxy NGC 4395, with broad components to the permitted line profiles, and we classify POX 52 as a Seyfert 1 galaxy. The host galaxy appears to be a dwarf elliptical, and its brightness profile is best fit by a Sérsic model with an index of 3.6+/-0.2 and a total magnitude of MV=-17.6. Applying mass-luminosity-line width scaling relations to estimate the black hole mass from the broad Hβ line width and nonstellar continuum luminosity, we find MBH~1.6×105Msolar. The stellar velocity dispersion in the host galaxy, measured from the Ca II λ8498, 8542 lines, is 36+/-5 km s-1, also suggestive of a black hole mass of order 105Msolar. Further searches for active nuclei in dwarf galaxies can provide unique constraints on the demographics of black holes in the mass range below 106Msolar.

  4. An Intermediate-Mass Black Hole in the Dwarf Seyfert 1 Galaxy POX 52

    Science.gov (United States)

    Barth, A.; Ho, L.; Sargent, W.

    2004-06-01

    We describe new observations of POX 52, a previously known but nearly forgotten example of a dwarf galaxy with an active nucleus. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an emission-line spectrum very similar to that of the dwarf Seyfert 1 galaxy NGC 4395, with clear broad components to the permitted line profiles. The host galaxy appears to be a dwarf elliptical; this is the only known case of a Seyfert nucleus in a galaxy of this type. Applying scaling relations to estimate the black hole mass from the broad Hβ linewidth and continuum luminosity, we find MBH ≈ 1.6×105 M⊙. The stellar velocity dispersion in the host galaxy is 36 km s-1, also suggestive of a black hole mass of order 105 M⊙. Further searches for AGNs in dwarf galaxies can provide crucial constraints on the demographics of black holes in the mass range below 106 M⊙.

  5. A study of the structure and kinematics of the narrow-line region in Seyfert galaxies

    International Nuclear Information System (INIS)

    Veilleux, S.

    1989-01-01

    The results of a high resolution study of the narrow emission line profiles of 16 Seyfert galaxies are presented. It is shown that the line profile parameters published in earlier low resolution studies are sometimes strongly influenced by resolution effects. In spite of these important systematic errors, many of the results derived from low resolution data are confirmed in the high resolution data. The narrow line profiles of Seyfert galaxies have a stronger base relative to core than a Gaussian. Most of the emission lines present a blueward asymmetry in the lower portion of their profile. In some galaxies, the line widths and/or line asymmetries are correlated with the ionization potential and/or critical density of the lines. There is a weak correlation between the line asymmetry and the dust content of the narrow line region (NLR). The large scatter in this relation, the absence of a similar correlation in Seyfert 1 to 1.5 galaxies, and the presence of a blue asymmetry in galaxies with dustfree line-emitting regions suggest that dust obscuration is not the only mechanism responsible for the line asymmetry in active galaxies. An optically-thick disk close to the nucleus is proposed as the other source of line asymmetry. An important result is that the host galaxy is probably playing a role in the kinematics of some of the gas in the NLR. A multicomponent model of the NLR is proposed to explain these results

  6. Distribution of surface brightness in Seyfert galaxies. III. Analysis of data

    International Nuclear Information System (INIS)

    Afanas'ev, V.L.; Doroshenko, V.T.; Terebizh, V.Yu.

    1987-01-01

    The observational data on the distribution of the surface brightness μ(r) in normal and Seyfert galaxies given in the first two parts of the study [1,2] are considered. The general form of μ(r) for r ≤ approximately equals 2 kpc is the same for the two groups of galaxies. The values of the parameters that characterize the central part of the spherical component are found, namely, the surface brightness μ 1 /sup (0)/, the brightness, the brightness gradient n 1 , and the color indices (U-B) 1 /sup (0)/ and (B-V) 1 /sup (0)/ at distance 1 kpc from the center. The range of variation of the basic parameters and the correlations of the parameters with each other and with the absolute magnitudes M/sub B//sup (0)/ of the galaxies find a natural explanation in the framework of the standard models of the spherical subsystems of galaxies. The relationships have approximately the same form for normal and Seyfert galaxies. The photometric characteristics of the central regions of Sy 1 and Sy 2 type galaxies are similar. The obtained results do not contradict the idea that all sufficiently bright spiral galaxies can pass through a Seyfert stage with a characteristic time of ∼10 8 yr

  7. Motion and properties of nuclear radio components in Seyfert galaxies seen with VLBI

    Science.gov (United States)

    Middelberg, E.; Roy, A. L.; Nagar, N. M.; Krichbaum, T. P.; Norris, R. P.; Wilson, A. S.; Falcke, H.; Colbert, E. J. M.; Witzel, A.; Fricke, K. J.

    2004-04-01

    We report EVN, MERLIN and VLBA observations at 18 cm, 6 cm and 3.6 cm of the Seyfert galaxies NGC 7674, NGC 5506, NGC 2110 and Mrk 1210 to study their structure and proper motions on pc scales and to add some constraints on the many possible causes of the radio-quietness of Seyferts. The component configurations in NGC 7674 and NGC 2110 are simple, linear structures, whereas the configurations in NGC 5506 and Mrk 1210 have multiple components with no clear axis of symmetry. We suggest that NGC 7674 is a low-luminosity compact symmetric object. Comparing the images at different epochs, we find a proper motion in NGC 7674 of (0.92±0.07) c between the two central components separated by 282 pc and, in NGC 5506, we find a 3 σ upper limit of 0.50 c for the components separated by 3.8 pc. Our results confirm and extend earlier work showing that the outward motion of radio components in Seyfert galaxies is non-relativistic on pc scales. We briefly discuss whether this non-relativistic motion is intrinsic to the jet-formation process or results from deceleration of an initially relativistic jet by interaction with the pc or sub-pc scale interstellar medium. We combined our sample with a list compiled from the literature of VLBI observations made of Seyfert galaxies, and found that most Seyfert nuclei have at least one flat-spectrum component on the VLBI scale, which was not seen in the spectral indices measured at arcsec resolution. We found also that the bimodal alignment of pc and kpc radio structures displayed by radio galaxies and quasars is not displayed by this sample of Seyferts, which shows a uniform distribution of misalignment between 0° and 90°. The frequent misalignment could result from jet precession or from deflection of the jet by interaction with gas in the interstellar medium.

  8. The extreme flare in III Zw 2:. Evolution of a radio jet in a Seyfert galaxy

    NARCIS (Netherlands)

    Brunthaler, A.; Falcke, H.D.E.; Bower, G.C.; Aller, M.F.; Aller, H.D.; Teräsranta, H.

    2005-01-01

    A very detailed monitoring of a radio flare in the Seyfert I galaxy III Zw 2 with the VLA and the VLBA is presented. The relative astrometry in the VLBA observations was precise to a few muas. The spectral and spatial evolutions of the source are closely linked, and these observations allowed us to

  9. The extreme flare in III Zw 2: evolution of a radio jet in a Seyfert galaxy

    NARCIS (Netherlands)

    Brunthaler, A.; Falcke, H.D.E.; Bower, G.C.; Aller, M.F.; Aller, H.D.; Teraesranta, H.

    2005-01-01

    A very detailed monitoring of a radio flare in the Seyfert I galaxy III Zw 2 with the VLA and the VLBA is presented. The relative astrometry in the VLBA observations was precise on a level of a few microarcseconds. Spectral and spatial evolution of the source are closely linked and these

  10. INVESTIGATING THE CORE MORPHOLOGY-SEYFERT CLASS RELATIONSHIP WITH HUBBLE SPACE TELESCOPE ARCHIVAL IMAGES OF LOCAL SEYFERT GALAXIES

    International Nuclear Information System (INIS)

    Rutkowski, M. J.; Hegel, P. R.; Kim, Hwihyun; Windhorst, R. A.; Tamura, Kazuyuki

    2013-01-01

    The unified model of active galactic nuclei (AGNs) has provided a successful explanation for the observed diversity of AGNs in the local universe. However, recent analysis of multi-wavelength spectral and image data suggests that the unified model is only a partial theory of AGNs, and may need to be augmented to remain consistent with all observations. Recent studies using high spatial resolution ground- and space-based observations of local AGNs show that Seyfert class and the ''core'' (r ∼ 20 ) and a new method which implements the Source Extractor software for feature detection in unsharp-mask images. This new method is designed explicitly to detect dust features in the images. We use our automated approach to classify the morphology of the AGN cores and determine that Sy2 galaxies visually appear, on average, to have more dust features than Sy1. With the exception of this ''dustiness'' however, we do not measure a strong correlation between the dust morphology and the Seyfert class of the host galaxy using quantitative techniques. We discuss the implications of these results in the context of the unified model.

  11. IC 3475: A stripped dwarf galaxy in the Virgo cluster

    International Nuclear Information System (INIS)

    Vigroux, L.; Thuan, T.X.; Vader, J.P.; Lachieze-Rey, M.

    1986-01-01

    We have obtained B and R CCD and H I observations of the Virgo dwarf galaxy IC 3475. The galaxy is remarkable for its very large diameter (approx.10 kpc for a Virgo distance modulus of 31) and is comparable in size to the large dwarfs discussed by Sandage and Binggeli. Its light profile is best fitted by an exponential law, characteristic of a dwarf Magellanic irregular galaxy. It possesses a central bar with many knots and inclusions concentrated toward the center of the galaxy. These knots and inclusions have the same color (B-Rapprox.1.5) as the rest of the galaxy and are best explained as intermediate-age (1--7 x 10 9 yr) star clusters such as those found in the Magellanic Clouds. Despite possessing the photometric structure of a dwarf Magellanic irregular galaxy, IC 3475 contains less than 5.3 x 10 6 M/sub sun/ of neutral hydrogen. Its hydrogen mass to blue light ratio is less than 0.01, approx.60 times less than the mean value observed for dwarf Magellanic irregulars. It is most likely that IC 3475, which is located near the core of the Virgo cluster, is a stripped dwarf galaxy. The very large size of the galaxy (its diameter is approx.1.8 times larger than that of ''normal'' dwarfs) appears to rule out evolution of IC 3475 from a normal dwarf irregular or to a normal dwarf elliptical

  12. Relativistic jets in narrow-line Seyfert 1 galaxies. New discoveries and open questions

    Directory of Open Access Journals (Sweden)

    D’Ammando F.

    2013-12-01

    Full Text Available Before the launch of the Fermi satellite only two classes of AGNs were known to produce relativistic jets and thus emit up to the γ-ray energy range: blazars and radio galaxies, both hosted in giant elliptical galaxies. The first four years of observations by the Large Area Telescope on board Fermi confirmed that these two are the most numerous classes of identified sources in the extragalactic γ-ray sky, but the discovery of γ-ray emission from 5 radio-loud narrow-line Seyfert 1 galaxies revealed the presence of a possible emerging third class of AGNs with relativistic jets. Considering that narrow-line Seyfert 1 galaxies seem to be typically hosted in spiral galaxy, this finding poses intriguing questions about the nature of these objects, the onset of production of relativistic jets, and the cosmological evolution of radio-loud AGN. Here, we discuss the radio-to-γ-rays properties of the γ-ray emitting narrow-line Seyfert 1 galaxies, also in comparison with the blazar scenario.

  13. Superwind Outflows in Seyfert Galaxies? : Large-Scale Radio Maps of an Edge-On Sample

    Science.gov (United States)

    Colbert, E.; Gallimore, J.; Baum, S.; O'Dea, C.

    1995-03-01

    Large-scale galactic winds (superwinds) are commonly found flowing out of the nuclear region of ultraluminous infrared and powerful starburst galaxies. Stellar winds and supernovae from the nuclear starburst provide the energy to drive these superwinds. The outflowing gas escapes along the rotation axis, sweeping up and shock-heating clouds in the halo, which produces optical line emission, radio synchrotron emission, and X-rays. These features can most easily be studied in edge-on systems, so that the wind emission is not confused by that from the disk. We have begun a systematic search for superwind outflows in Seyfert galaxies. In an earlier optical emission-line survey, we found extended minor axis emission and/or double-peaked emission line profiles in >~30% of the sample objects. We present here large-scale (6cm VLA C-config) radio maps of 11 edge-on Seyfert galaxies, selected (without bias) from a distance-limited sample of 23 edge-on Seyferts. These data have been used to estimate the frequency of occurrence of superwinds. Preliminary results indicate that four (36%) of the 11 objects observed and six (26%) of the 23 objects in the distance-limited sample have extended radio emission oriented perpendicular to the galaxy disk. This emission may be produced by a galactic wind blowing out of the disk. Two (NGC 2992 and NGC 5506) of the nine objects for which we have both radio and optical data show good evidence for a galactic wind in both datasets. We suggest that galactic winds occur in >~30% of all Seyferts. A goal of this work is to find a diagnostic that can be used to distinguish between large-scale outflows that are driven by starbursts and those that are driven by an AGN. The presence of starburst-driven superwinds in Seyferts, if established, would have important implications for the connection between starburst galaxies and AGN.

  14. Time dependent emission line profiles in the radially streaming particle model of Seyfert galaxy nuclei and quasi-stellar objects

    Science.gov (United States)

    Hubbard, R.

    1974-01-01

    The radially-streaming particle model for broad quasar and Seyfert galaxy emission features is modified to include sources of time dependence. The results are suggestive of reported observations of multiple components, variability, and transient features in the wings of Seyfert and quasi-stellar emission lines.

  15. Hubble Space Telescope Imaging of the Circumnuclear Environments of the CfA Seyfert Galaxies: Nuclear Spirals and Fueling

    Science.gov (United States)

    Pogge, Richard W.; Martini, Paul

    2002-01-01

    We present archival Hubble Space Telescope (HST) images of the nuclear regions of 43 of the 46 Seyfert galaxies found in the volume limited,spectroscopically complete CfA Redshift Survey sample. Using an improved method of image contrast enhancement, we created detailed high-quality " structure maps " that allow us to study the distributions of dust, star clusters, and emission-line gas in the circumnuclear regions (100-1000 pc scales) and in the associated host galaxy. Essentially all of these Seyfert galaxies have circumnuclear dust structures with morphologies ranging from grand-design two-armed spirals to chaotic dusty disks. In most Seyfert galaxies there is a clear physical connection between the nuclear dust spirals on hundreds of parsec scales and large-scale bars and spiral arms in the host galaxies proper. These connections are particularly striking in the interacting and barred galaxies. Such structures are predicted by numerical simulations of gas flows in barred and interacting galaxies and may be related to the fueling of active galactic nuclei by matter inflow from the host galaxy disks. We see no significant differences in the circumnuclear dust morphologies of Seyfert 1s and 2s, and very few Seyfert 2 nuclei are obscured by large-scale dust structures in the host galaxies. If Sevfert 2s are obscured Sevfert Is, then the obscuration must occur on smaller scales than those probed by HST.

  16. An optical and near-infrared polarization survey of Seyfert and broad-line radio galaxies. Pt. 1

    International Nuclear Information System (INIS)

    Brindle, C.; Hough, J.H.; Bailey, J.A.; Axon, D.J.; Ward, M.J.; McLean, I.S.

    1990-01-01

    We present new broad-band optical and near-infrared (0.44-2.2 μm) flux density and polarization measurements of a sample of 71 Seyfert galaxies and three broad-line radio galaxies. We confirm the results of earlier studies which show that the polarization of Seyferts is generally low in the V-band and at longer wavelengths, but in the B-band somewhat higher polarizations are commonly found. After correction has been made for the effects of stellar dilution, we find that Seyfert 2 nuclei are probably more highly polarized than Seyfert 1's. The small sample of Seyfert 2's selected using the 'warm' IRAS colour criterion tend to be more highly polarised than those selected by optical techniques. (author)

  17. Nuclear star formation activity and black hole accretion in nearby Seyfert galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Esquej, P. [Centro de Astrobiología, INTA-CSIC, Villafranca del Castillo, E-28850, Madrid (Spain); Alonso-Herrero, A.; Hernán-Caballero, A. [Instituto de Física de Cantabria, CSIC-Universidad de Cantabria, E-39005 Santander (Spain); González-Martín, O.; Ramos Almeida, C.; Rodríguez Espinosa, J. M. [Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea, E-38205, La Laguna (Spain); Hönig, S. F. [UCSB Department of Physics, Broida Hall 2015H, Santa Barbara, CA (United States); Roche, P. [Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom); Mason, R. E. [Gemini Observatory, Northern Operations Center, 670 North A' ohoku, HI 96720 (United States); Díaz-Santos, T. [Spitzer Science Center, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Levenson, N. A. [Gemini Observatory, Casilla 603, La Serena (Chile); Aretxaga, I. [Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Aptdo. Postal 51 y 216, 72000 Puebla (Mexico); Packham, C. [Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249 (United States)

    2014-01-01

    Recent theoretical and observational works indicate the presence of a correlation between the star-formation rate (SFR) and active galactic nucleus (AGN) luminosity (and, therefore, the black hole accretion rate, M-dot {sub BH}) of Seyfert galaxies. This suggests a physical connection between the gas-forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. We compiled the largest sample of Seyfert galaxies to date with high angular resolution (∼0.''4-0.''8) mid-infrared (8-13 μm) spectroscopy. The sample includes 29 Seyfert galaxies drawn from the AGN Revised Shapley-Ames catalog. At a median distance of 33 Mpc, our data allow us to probe nuclear regions on scales of ∼65 pc (median value). We found no general evidence of suppression of the 11.3 μm polycyclic aromatic hydrocarbon (PAH) emission in the vicinity of these AGN, and we used this feature as a proxy for the SFR. We detected the 11.3 μm PAH feature in the nuclear spectra of 45% of our sample. The derived nuclear SFRs are, on average, five times lower than those measured in circumnuclear regions of 600 pc in size (median value). However, the projected nuclear SFR densities (median value of 22 M {sub ☉} yr{sup –1} kpc{sup –2}) are a factor of 20 higher than those measured on circumnuclear scales. This indicates that the SF activity per unit area in the central ∼65 pc region of Seyfert galaxies is much higher than at larger distances from their nuclei. We studied the connection between the nuclear SFR and M-dot {sub BH} and showed that numerical simulations reproduce our observed relation fairly well.

  18. Superwind Outflow in Seyfert Galaxies? : Optical Observations of an Edge-On Sample

    Science.gov (United States)

    Colbert, E.; Gallimore, J.; Baum, S.; O'Dea, C.; Lehnert, M.

    1994-12-01

    Large-scale galactic winds (superwinds) are commonly found flowing out of the nuclear region of ultraluminous infrared and powerful starburst galaxies. Stellar winds and supernovae from the nuclear starburst are thought to provide the energy to drive these superwinds. The outflowing gas escapes along the rotation axis, sweeping up and shock-heating clouds in the halo, which produces optical line emission, X-rays and radio synchrotron emission. These features can most easily be studied in edge-on systems, so that the wind emission is not confused by that from the disk. Diffuse radio emission has been found (Baum et al. 1993, ApJ, 419, 553) to extend out to kpc-scales in a number of edge-on Seyfert galaxies. We have therefore launched a systematic search for superwind outflows in Seyferts. We present here narrow-band optical images and optical spectra for a sample of edge-on Seyferts. These data have been used to estimate the frequency of occurence of superwinds. Approximately half of the sample objects show evidence for extended emission-line regions which are preferentially oriented perpendicular to the galaxy disk. It is possible that these emission-line regions may be energized by a superwind outflow from a circumnuclear starburst, although there may also be a contribution from the AGN itself. A goal of this work is to find a diagnostic that can be used to distinguish between large-scale outflows that are driven by starbursts and those that are driven by an AGN. The presence of starburst-driven superwinds in Seyferts, if established, would have important implications for the connection between starburst galaxies and AGN.

  19. HI observations of the irregular galaxy IC 10

    International Nuclear Information System (INIS)

    Shostak, G.S.; Woerden, H. van

    1983-01-01

    The authors have made radio synthesis observations of the galaxy IC 10 with resolutions of 30 arcsec and 8 km/sec in the neutral hydrogen line using the Westerbork telescope. These confirm Shostak's (1974) result that, in the central region of IC 10, the velocity gradient is opposite to that later measured by single-dish in the outer regions. The suggestion by Cohen (1979) that the velocity gradient reversal is due to IC 10 being nearly face-on and warped is consistent with the new data. (Auth.)

  20. Radio and infrared observations of (almost) one hundred non-Seyfert Markarian galaxies

    Science.gov (United States)

    Dressel, Linda L.

    1987-01-01

    The 13 cm flux densities of 96 non-Seyfert Markarian galaxies were measured at Arecibo Observatory. Far infrared flux densities have been published for 78 of these galaxies in the IRAS catalog. The radio, infrared, and optical fluxes of these galaxies and of a magnitude limited sample of normal galaxies were compared to clarify the nature of the radio emission in Markarian galaxies. It was found that Markarian galaxies of a given apparent magnitude and Hubble type generally have radio fluxes several times higher that the fluxes typical of normal galaxies of the same magnitude and type. Remarkably, the ratio of radio flux to far infrared flux is nearly the same for most of these starburst galaxies and for normal spiral disks. However, the compact and peculiar Markarian galaxies consistently have about 60% more radio flux per unit infrared flux than the other Markarian galaxies and the normal spirals. It is not clear whether this difference reflects a difference in the evolution of the starbursts in these galaxies or whether there is excess radio emission of nonstellar origin.

  1. Hidden Broad Line Seyfert 2 Galaxies in the CfA and 12micron Samples

    OpenAIRE

    Tran, Hien D.

    2001-01-01

    We report the results of a spectropolarimetric survey of the CfA and 12micron samples of Seyfert 2 galaxies (S2s). Polarized (hidden) broad line regions (HBLRs) are confirmed in a number of galaxies, and several new cases (F02581-1136, MCG -3-58-7, NGC 5995, NGC 6552, NGC 7682) are reported. The 12micron S2 sample shows a significantly higher incidence of HBLR (50%) than its CfA counterpart (30%), suggesting that the latter may be incomplete in hidden AGNs. Compared to the non-HBLR S2s, the H...

  2. Long time scale hard X-ray variability in Seyfert 1 galaxies

    Science.gov (United States)

    Markowitz, Alex Gary

    This dissertation examines the relationship between long-term X-ray variability characteristics, black hole mass, and luminosity of Seyfert 1 Active Galactic Nuclei. High dynamic range power spectral density functions (PSDs) have been constructed for six Seyfert 1 galaxies. These PSDs show "breaks" or characteristic time scales, typically on the order of a few days. There is resemblance to PSDs of lower-mass Galactic X-ray binaries (XRBs), with the ratios of putative black hole masses and variability time scales approximately the same (106--7) between the two classes of objects. The data are consistent with a linear correlation between Seyfert PSD break time scale and black hole mass estimate; the relation extrapolates reasonably well over 6--7 orders of magnitude to XRBs. All of this strengthens the case for a physical similarity between Seyfert galaxies and XRBs. The first six years of RXTE monitoring of Seyfert 1s have been systematically analyzed to probe hard X-ray variability on multiple time scales in a total of 19 Seyfert is in an expansion of the survey of Markowitz & Edelson (2001). Correlations between variability amplitude, luminosity, and black hole mass are explored, the data support the model of PSD movement with black hole mass suggested by the PSD survey. All of the continuum variability results are consistent with relatively more massive black holes hosting larger X-ray emission regions, resulting in 'slower' observed variability. Nearly all sources in the sample exhibit stronger variability towards softer energies, consistent with softening as they brighten. Direct time-resolved spectral fitting has been performed on continuous RXTE monitoring of seven Seyfert is to study long-term spectral variability and Fe Kalpha variability characteristics. The Fe Kalpha line displays a wide range of behavior but varies less strongly than the broadband continuum. Overall, however, there is no strong evidence for correlated variability between the line and

  3. Serendipitous discovery of warm absorbers in the Seyfert 2 galaxy IRAS 18325-5926

    International Nuclear Information System (INIS)

    Zhang Shuinai; Gu Qiusheng; Peng Zhixin; Ji Li

    2011-01-01

    Warm absorption is a common phenomenon in Seyfert 1s and quasars, but is rare in Seyfert 2s. We report the detection of warm absorbers with high energy resolution in the Seyfert 2 galaxy IRAS 18325-5926 for the first time with Chandra HETGS spectra. An intrinsic absorbing line system with an outflow velocity ∼ 400 km s -1 was found, which is contributed by two warm absorbers with FWHM of 570 km s -1 and 1360 km s -1 , respectively. The two absorbers were adjacent, and moving transversely across our line of sight. We constrained the distance between the center and the absorbers to be a small value, suggesting that the absorbers may originate from the highly ionized accretion disk wind ejected five years ago. The perspective of this type 2 Seyfert provides the best situation in which to investigate the vertical part of the funnel-like outflows. Another weak absorbing line system with zero redshift was also detected, which could be due to Galactic absorption with very high temperature or an intrinsic outflow with a very high velocity ∼ 6000 km s -1 . (research papers)

  4. A Multiwavelength Study of POX 52, a Dwarf Seyfert Galaxy with an Intermediate Mass Black Hole

    Science.gov (United States)

    Barth, Aaron

    2004-09-01

    POX 52 is a Seyfert 1 galaxy with unprecedented properties: its host galaxy is a dwarf elliptical, and its stellar velocity dispersion is only 36 km/s. The stellar velocity dispersion and the broad emission-line widths both suggest a black hole mass of order 10^5 solar masses. We request HST ACS/HRC imaging to perform a definitive measurement of the host galaxy structure; STIS UV and optical spectroscopy to study the nonstellar continuum and the structure of the broad-line region; and Chandra ACIS imaging to investigate the spectral and variability properties of the X-ray emission. The results of this program will give a detailed understanding of the host galaxy and accretion properties of one of the very few known black holes in the mass range around 10^5 solar masses.

  5. Searches for H2O masers toward narrow-line Seyfert 1 galaxies

    Science.gov (United States)

    Yoshiaki, Hagiwara; Doi, Akihiro; Hachisuka, Kazuya; Horiuchi, Shinji

    2018-05-01

    We present searches for 22 GHz H2O masers toward 36 narrow-line Seyfert 1 galaxies (NLS1s), selected from known NLS1s with vsys ≲ 41000 km s-1. Out of the 36 NLS1s in our sample, 11 have been first surveyed in our observations, while the observations of other NLS1s were previously reported in literature. In our survey, no new water maser source from NLS1s was detected at the 3σ rms level of 8.4 mJy to 144 mJy, which depends on different observing conditions or inhomogeneous sensitivities of each observation using three different telescopes. It is likely that the non-detection of new masers in our NLS1 sample is primarily due to insufficient sensitivities of our observations. Including the five known NLS1 masers, the total detection rate of the H2O maser in NLS1s is not remarkably different from that of type 2 Seyfert galaxies or LINERs. However, more extensive and systematic searches of NLS1 would be required for a statistical discussion of the detection rate of the NLS1 maser, compared with that of type 2 Seyferts or LINERs.

  6. Spectral properties of the narrow-line region in Seyfert galaxies selected from the SDSS-DR7

    Science.gov (United States)

    Vaona, L.; Ciroi, S.; Di Mille, F.; Cracco, V.; La Mura, G.; Rafanelli, P.

    2012-12-01

    Although the properties of the narrow-line region (NLR) of active galactic nuclei (AGN) have been deeply studied by many authors in the past three decades, many questions are still open. The main goal of this work is to explore the NLR of Seyfert galaxies by collecting a large statistical spectroscopic sample of Seyfert 2 and Intermediate-type Seyfert galaxies having a high signal-to-noise ratio in order to take advantage of a high number of emission lines to be accurately measured. 2153 Seyfert 2 and 521 Intermediate-type Seyfert spectra were selected from Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) with a diagnostic diagram based on the oxygen emission-line ratios. All the emission lines, broad components included, were measured by means of a self-developed code, after the subtraction of the stellar component. Physical parameters, such as internal reddening, ionization parameter, temperature, density, gas and stellar velocity dispersion were determined for each object. Furthermore, we estimated mass and radius of the NLR, kinetic energy of the ionized gas and black hole accretion rate. From the emission-line analysis and the estimated physical properties, it appears that the NLR is similar in Seyfert 2 and Intermediate-Seyfert galaxies. The only differences, lower extinction, gas kinematics in general not dominated by the host galaxy gravitational potential and higher percentage of [O III]λ5007 blue asymmetries in Intermediate-Seyfert, can be ascribed to an effect of inclination of our line of sight with respect to the torus axis.

  7. PHYSICAL CONDITIONS IN THE INNER NARROW-LINE REGION OF THE SEYFERT 2 GALAXY MARKARIAN 573

    International Nuclear Information System (INIS)

    Kraemer, S. B.; Trippe, M. L.; Crenshaw, D. M.; Fischer, T. C.; Melendez, M.; Schmitt, H. R.

    2009-01-01

    We have examined the physical conditions within a bright emission-line knot in the inner narrow-line region (NLR) of the Seyfert 2 galaxy Mrk 573 using optical spectra and photoionization models. The spectra were obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph, through the 0.''2 x 52.''0 slit, at a position angle of -71. 0 2, with the G430L and G750M gratings. Comparing the spatial emission-line profiles, we found [Fe X] λ 6734 barely resolved, [O III] λ5007 centrally peaked, but broader than [Fe X], and [O II] λ3727 the most extended. Spectra of the central knot were extracted from a region 1.''1 in extent, corresponding to the full width at zero intensity in the cross-dispersion direction, of the knot. The spectra reveal that [Fe X] is broader in velocity width and blueshifted compared with lines from less ionized species. Our estimate of the bolometric luminosity indicates that the active galactic nucleus (AGN) is radiating at or above its Eddington luminosity, which is consistent with its identification as a hidden Narrow-Line Seyfert 1. We were able to successfully match the observed emission-line ratios with a three-component photoionization model. Two components, one to account for the [O III] emission and another in which the [Fe X] arises, are directly ionized by the AGN, while [O II] forms in a third component, which is ionized by a heavily absorbed continuum. Based on our assumed ionizing continuum and the model parameters, we determined that the two directly ionized components are ∼55 pc from the AGN. We have found similar radial distances for the central knots in the Seyfert 2 galaxies Mrk 3 and NGC 1068, but much smaller radial distances for the inner NLR in the Seyfert 1 galaxies NGC 4151 and NGC 5548. Although in general agreement with the unified model, these results suggest that the obscuring material in Seyfert galaxies extends out to at least tens of parsecs from the AGN.

  8. Evolutionary behaviour of AGN: Investigations on BL Lac objects and Seyfert II galaxies

    Science.gov (United States)

    Beckmann, V.

    2000-12-01

    The evolution and nature of AGN is still one of the enigmatic questions in astrophysics. While large and complete Quasar samples are available, special classes of AGN, like BL Lac objects and Seyfert II galaxies, are still rare objects. In this work I present two new AGN samples. The first one is the HRX-BL Lac survey, resulting in a sample of X-ray selected BL Lac objects. This sample results from 223 BL Lac candidates based on a correlation of X-ray sources with radio sources. The identification of this sample is 98% complete. 77 objects have been identified as BL Lac objects and form the HRX-BL Lac complete sample, the largest homogeneous sample of BL Lac objects existing today. For this sample, redshifts are now known for 62 objects (81 %). In total I present 101 BL Lac objects in the enlarged HRX-BL Lac survey, for which redshift information is available for 84 objects. During the HRX-BL Lac survey I found several objects of special interest. 1ES 1517+656 turned out to be the brightest known BL Lac object in the universe. 1ES 0927+500 could be the first BL Lac object with a line detected in the X-ray region. RX J1211+2242 is probably the the counterpart of the up to now unidentified gamma-ray source 3EG J1212+2304. Additionally I present seven candidates for ultra high frequency peaked BL Lac objects. RX J1054+3855 and RX J1153+3517 are rare high redshift X-ray bright QSO or accreting binary systems with huge magnetic fields. For the BL Lac objects I suggest an unified scenario in which giant elliptical galaxies, formed by merging events of spiral galaxies at z > 2, start as powerful, radio dominated BL Lacs. As the jet gets less powerful, the BL Lacs start to get more X-ray dominated, showing less total luminosities (for z definition to objects with a calcium break up to 40%, but do not support for the HBL the idea of allowing emission lines in the spectra of BL Lac galaxies. A way to find high redshift BL Lac objects might be the identification of faint X

  9. Distribution and Kinematics of Ionized Gas in the central 500pc of Seyfert Galaxies

    Science.gov (United States)

    Hyland, Ella; Hicks, Erin K. S.; Kade, Kiana

    2018-06-01

    We have characterized the spatial distribution and kinematics of the ionized hydrogen gas in a sample of 40 Seyfert galaxies as part of the KONA (Keck OSIRIS Nearby AGN) survey. An analysis of the narrow Brackett Gamma emission (2.16 microns) in the central 500 pc of these local AGN will be presented. Measurements include the azimuthal averages of the flux distribution, velocity dispersion, and emission line equivalent width. In addition, the excitation of the Brackett Gamma emission is considered using the ratio of its flux with that of molecular hydrogen (2.12 microns) as a diagnostic. A comparison of the circumnuclear narrow Brackett Gamma emission characteristics in the Seyfert type 1 and type 2 subsamples will also be presented.

  10. Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

    Science.gov (United States)

    Rakshit, Suvendu; Stalin, C. S.

    2017-06-01

    We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z anti-correlated with Fe II strength but correlated with the width of the Hβ line. The well-known anti-correlation of variability-luminosity and the variability-Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

  11. THE ROLE OF RADIATION PRESSURE IN THE NARROW LINE REGIONS OF SEYFERT HOST GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Davies, Rebecca L.; Dopita, Michael A.; Kewley, Lisa; Groves, Brent; Sutherland, Ralph; Hampton, Elise J.; Banfield, Julie [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Shastri, Prajval; Kharb, Preeti; Bhatt, Harish [Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034 (India); Scharwächter, Julia [LERMA, Observatoire de Paris, PSL, CNRS, Sorbonne Universités, UPMC, F-75014 Paris (France); Jin, Chichuan [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Zaw, Ingyin [New York University (Abu Dhabi), 70 Washington Square S, New York, NY 10012 (United States); James, Bethan [Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA (United Kingdom); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Srivastava, Shweta, E-mail: Rebecca.Davies@anu.edu.au [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009 (India)

    2016-06-10

    We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-active galactic nucleus (AGN) mixing curves on standard emission line diagnostic diagrams, which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ∼ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ∼ 0 to −3.2 ≲ log U ≲ −3.4. Where radiation pressure is dominant, the AGN regulates the density of the interstellar medium on kiloparsec scales and may therefore have a direct impact on star formation activity and/or the incidence of outflows in the host galaxy to scales far beyond the zone of influence of the black hole. We find that both radiation pressure dominated and gas pressure dominated ENLRs are dynamically active with evidence for outflows, indicating that radiation pressure may be an important source of AGN feedback even when it is not dominant over the entire ENLR.

  12. The unusual kinematics of the galaxy IC 10

    International Nuclear Information System (INIS)

    Cohen, R.J.

    1979-01-01

    Observations of neutral hydrogen emission from the galaxy IC 10 show a large outer envelope of gas more than 1 0 in extent. The emission has a velocity gradient along the major axis in the opposite sense to that of the central concentration mapped by Shostak. This unusual velocity reversal can be interpreted in terms of a warped gas-layer in normal rotation and seen face-on. (author)

  13. Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Rakshit, Suvendu; Stalin, C. S., E-mail: suvenduat@gmail.com [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore-560034 (India)

    2017-06-20

    We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z < 0.8 to investigate any differences in their OV properties. Using archival optical V -band light curves from the Catalina Real Time Transient Survey that span 5–9 years and modeling them using damped random walk, we estimated the amplitude of variability. We found that NLSy1 galaxies as a class show lower amplitude of variability than their broad-line counterparts. In the sample of both NLSy1 and BLSy1 galaxies, radio-loud sources are found to have higher variability amplitude than radio-quiet sources. Considering only sources that are detected in the X-ray band, NLSy1 galaxies are less optically variable than BLSy1 galaxies. The amplitude of variability in the sample of both NLSy1 and BLSy1 galaxies is found to be anti-correlated with Fe ii strength but correlated with the width of the H β line. The well-known anti-correlation of variability–luminosity and the variability–Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

  14. GAS OUTFLOWS IN SEYFERT GALAXIES: EFFECTS OF STAR FORMATION VERSUS AGN FEEDBACK

    Energy Technology Data Exchange (ETDEWEB)

    Melioli, C.; Pino, E. M. de Gouveia Dal, E-mail: claudio.melioli@iag.usp.br, E-mail: dalpino@iag.usp.br [Department of Astronomy (IAG-USP), University of Sao Paulo (Brazil)

    2015-10-20

    Large-scale, weakly collimated outflows are very common in galaxies with large infrared luminosities. In complex systems in particular, where intense star formation (SF) coexists with an active galactic nucleus (AGN), it is not clear yet from observations whether the SF, the AGN, or both are driving these outflows. Accreting supermassive black holes are expected to influence their host galaxies through kinetic and radiative feedback processes, but in a Seyfert galaxy, where the energy emitted in the nuclear region is comparable to that of the body of the galaxy, it is possible that stellar activity is also playing a key role in these processes. In order to achieve a better understanding of the mechanisms driving the gas evolution especially at the nuclear regions of these galaxies, we have performed high-resolution three-dimensional hydrodynamical simulations with radiative cooling considering the feedback from both SF regions, including supernova (Type I and II) explosions and an AGN jet emerging from the central region of the active spiral galaxy. We computed the gas mass lost by the system, separating the role of each of these injection energy sources on the galaxy evolution, and found that at scales within 1 kpc an outflow can be generally established considering intense nuclear SF only. The jet alone is unable to drive a massive gas outflow, although it can sporadically drag and accelerate clumps of the underlying outflow to very high velocities.

  15. A High Definition View of AGN Feedback: Chandra Imaging of Nearby Seyfert Galaxies

    Science.gov (United States)

    Wang, Junfeng; Fabbiano, G.; Risaliti, G.; Elvis, M.; Karovska, M.; Zezas, A.; Mundell, C. G.

    2010-03-01

    To improve the physics of AGN feedback, it is crucial to evaluate the true role of outflows on galaxy evolution observationally. I will present new results from Chandra spectral imaging of nearby Seyfert galaxies, which offer unique opportunities to examine feedback in action in much greater detail than at high redshift. Exploiting Chandra's highest possible resolution, we are able to study structures in NGC 4151 on spatial scales of 0.5 arcsec (30 pc), showing an extended X-ray morphology overall consistent with the optical NLR. We find that most of the NLR clouds in NGC 4151 have [OIII] to soft X-ray ratio consistent with the values observed in NLRs of some Seyfert 2 galaxies, which indicates a uniform ionization parameter even at large radii. We examine various X-ray emission mechanisms of the radio jet and consider thermal emission from interaction between radio outflow and the NLR clouds the most probable origin for the X-ray emission associated with the jet.

  16. The Different Nature in Seyfert 2 Galaxies With and Without Hidden Broad-Line Regions

    OpenAIRE

    Wu, Yu-Zhong; Zhang, En-Peng; Liang, Yan-Chun; Zhang, Cheng-Min; Zhao, Yong-Heng

    2011-01-01

    We compile a large sample of 120 Seyfert 2 galaxies (Sy2s) which contains 49 hidden broad-line region (HBLR) Sy2s and 71 non-HBLR Sy2s. From the difference in the power sources between two groups, we test if HBLR Sy2s are dominated by active galactic nuclei (AGNs), and if non-HBLR Sy2s are dominated by starbursts. We show that: (1) HBLR Sy2s have larger accretion rates than non-HBLR Sy2s; (2) HBLR Sy2s have larger \\Nev $\\lambda 14.32$/\\Neii $\\lambda 12.81$ and \\oiv $\\lambda 25.89$/\\Neii $\\lam...

  17. Variability of Fe II Emission Features in the Seyfert 1 Galaxy NGC 5548

    DEFF Research Database (Denmark)

    Vestergaard, Marianne; Peterson, B. M.

    2005-01-01

    We study the low-contrast Fe II emission blends in the ultraviolet (1250--2200A) and optical (4000--6000A) spectra of the Seyfert 1 galaxy NGC 5548 and show that these features vary in flux and that these variations are correlated with those of the optical continuum. The amplitude of variability ...... are correlated indicates that line fluorescence in a photoionized plasma, rather than collisional excitation, is responsible for the Fe II emission. The iron emission templates are available upon request....

  18. Are Narrow Line Seyfert 1 Galaxies Viewed Pole-on?

    Science.gov (United States)

    2011-04-01

    0.2’’ respectively. Figure 1 displays the position of each slit over a Barbosa et al. (2009) GMOS IFU image of the [S III] flux (which originates...C. Winge, H. Schmitt: Gemini/ GMOS IFU gas velocity ’tomography’ of the narrow line region of nearby active galaxies, MNRAS, 396 (2009) 2. [2] D...1995) 81. 4 P o S ( N L S 1 ) 0 5 0 Are NLS1s Pole-on? Travis C. Fischer 5 Figure 1: NGC 4051 GMOS IFU image showing integrated [SIII] flux

  19. Hidden Broad-line Regions in Seyfert 2 Galaxies: From the Spectropolarimetric Perspective

    International Nuclear Information System (INIS)

    Du, Pu; Wang, Jian-Min; Zhang, Zhi-Xiang

    2017-01-01

    The hidden broad-line regions (BLRs) in Seyfert 2 galaxies, which display broad emission lines (BELs) in their polarized spectra, are a key piece of evidence in support of the unified model for active galactic nuclei (AGNs). However, the detailed kinematics and geometry of hidden BLRs are still not fully understood. The virial factor obtained from reverberation mapping of type 1 AGNs may be a useful diagnostic of the nature of hidden BLRs in type 2 objects. In order to understand the hidden BLRs, we compile six type 2 objects from the literature with polarized BELs and dynamical measurements of black hole masses. All of them contain pseudobulges. We estimate their virial factors, and find the average value is 0.60 and the standard deviation is 0.69, which agree well with the value of type 1 AGNs with pseudobulges. This study demonstrates that (1) the geometry and kinematics of BLR are similar in type 1 and type 2 AGNs of the same bulge type (pseudobulges), and (2) the small values of virial factors in Seyfert 2 galaxies suggest that, similar to type 1 AGNs, BLRs tend to be very thick disks in type 2 objects.

  20. X-Ray Spectral Properties of Seven Heavily Obscured Seyfert 2 Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, S.; Ajello, M. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Comastri, A. [INAF—Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Cusumano, G.; Parola, V. La; Segreto, A., E-mail: smarche@clemson.edu [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy)

    2017-02-10

    We present the combined Chandra and Swift -BAT spectral analysis of seven Seyfert 2 galaxies selected from the Swift -BAT 100 month catalog. We selected nearby ( z ≤ 0.03) sources lacking a ROSAT counterpart that never previously been observed with Chandra in the 0.3–10 keV energy range, and targeted these objects with 10 ks Chandra ACIS-S observations. The X-ray spectral fitting over the 0.3–150 keV energy range allows us to determine that all the objects are significantly obscured, with N{sub H} ≥ 10{sup 23} cm{sup −2} at a >99% confidence level. Moreover, one to three sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs; i.e., N{sub H}≥10{sup 24} cm{sup −2}). We also test the recent spectral curvature method developed by Koss et al. to find candidate CT-AGNs, finding a good agreement between our results and their predictions. Because the selection criteria we adopted were effective in detecting highly obscured AGNs, further observations of these and other Seyfert 2 galaxies selected from the Swift -BAT 100 month catalog will allow us to create a statistically significant sample of highly obscured AGNs, therefore providing a better understanding of the physics of the obscuration processes.

  1. X-Ray Variability Characteristics of the Seyfert 1 Galaxy NGC 3783

    Science.gov (United States)

    Markowitz, A.

    2005-12-01

    We have characterized the energy-dependent X-ray variability properties of the Seyfert 1 galaxy NGC 3783 using archival XMM-Newton and Rossi X-Ray Timing Explorer data. The high-frequency fluctuation power spectral density function (PSD) slope is consistent with flattening toward higher energies. Light-curve cross-correlation functions yield no significant lags, but peak coefficients generally decrease as energy separation of the bands increases on both short and long timescales. We have measured the coherence between various X-ray bands over the temporal frequency range of 6×10-8-1×10-4 Hz; this range includes the temporal frequency of the low-frequency PSD break tentatively detected by Markowitz et al. and includes the lowest temporal frequency over which coherence has been measured in any active galactic nucleus to date. Coherence is generally near unity at these temporal frequencies, although it decreases slightly as energy separation of the bands increases. Temporal frequency-dependent phase lags are detected on short timescales; phase lags are consistent with increasing as energy separation increases or as temporal frequency decreases. All of these results are similar to those obtained previously for several Seyfert galaxies and stellar mass black hole systems. Qualitatively, these results are consistent with the variability models of Kotov et al. and Lyubarskii, wherein the X-ray variability is due to inwardly propagating variations in the local mass accretion rate.

  2. A mid- to far-infrared variability study of the intermediate Seyfert galaxy, Mk 6

    International Nuclear Information System (INIS)

    Clement, R.; Sembay, S.; Coe, M.J.; Hanson, C.G.

    1988-01-01

    A mid- to far-infrared (MFIR) variability study of the intermediate Seyfert galaxy, Mk 6, is presented using data from the Infrared Astronomical Satellite (IRAS). We have analysed 25 observations of this source covering a period of about 1 month. Within the expected errors, the source shows no evidence for variability and this may be an indication that there is a strong contribution to the MFIR emission from thermal re-radiation by dust. This interpretation is consistent with previous studies which suggest that the bulk of the far-infrared (30 -100 μm) emission in Seyfert galaxies originates from cool (35 - 75 K) dust associated with star formation regions in the surrounding envelope of the active nucleus. The lack of variability at 12 and 25 μm can also be readily explained by dust emission. However, in this case, the dust temperatures required to produce emission at these wavelengths makes the narrow-line region a more feasible location for the dust grains. (author)

  3. Variable blurred reflection in the narrow-line Seyfert 1 galaxy Mrk 493

    Science.gov (United States)

    Bonson, K.; Gallo, L. C.; Wilkins, D. R.; Fabian, A. C.

    2018-04-01

    We examine a 200 ks XMM-Newton observation of the narrow-line Seyfert 1 galaxy Mrk 493. The active galaxy was half as bright as in a previous 2003 snapshot observation and the current lower flux enables a study of the putative reflection component in detail. We determine the characteristics of the 2015 X-ray continuum by first analyzing the short-term variability using model-independent techniques. We then continue with a time-resolve analysis including spectral fitting and modelling the fractional variability. We determine that the variability arises from changes in the amount of primary flux striking the accretion disk, which induces changes in the ionization parameter and flux of the blurred reflection component. The observations seem consistent with the picture that the primary source is of roughly constant brightness and that variations arise from changes in the degree of light bending happening in the vicinity of the supermassive black hole.

  4. Survey of Milliarcsec Structure in Eight Seyfert Galaxies: Results on NGC 1068 and NGC 4151

    Science.gov (United States)

    Roy, A. L.; Ulvestad, J. S.; Colbert, E. J. M.; Wilson, A. S.; Norris, R. P.

    We are surveying eight nearby Seyfert galaxies (four Sy1s and four Sy2s) that have compact radio cores, using the VLBA. We are interested in parsec-scale morphology and low-frequency absorption effects, and so are observing four frequencies (1.6, 4.8, 8.4 and 15 GHz) to get spectral-index diagnostics. In this paper, we present results on two galaxies, NGC 1068 and NGC 4151. NGC 4151 shows a curved radio jet on the sub-parsec scale, with the smallest scale structure misaligned by $55^\\circ$ from the jet on scales of parsecs to hundreds of parsecs. NGC 1068 contains several components in the inner tens of parsecs, with those components showing a variety of absorption and resolution effects.

  5. Parsec-scale jets and tori in seyfert galaxies

    Science.gov (United States)

    Roy, A. L.; Wrobel, J. M.; Wilson, A. S.; Ulvestad, J. S.; Norris, R. P.; Mundell, C. G.; Krichbaum, T. P.; Falcke, H.; Colbert, E. J. M.

    2001-01-01

    H. Falcke, T.P. Krichbaum, C.G. Mundell, J.S. Ulvestad, A.S. Wilson, J.M. Wrobel Active galaxies tend to be powerful or weak radio sources, and we still do not understand the underlying cause. Perhaps the engine is the same in both systems and the jet gets disrupted by dense interstellar medium in radio-quiet objects, or else the difference is intrinsic with jet power scaling with black hole spin. To distinguish, one can look for signs of interaction between the jet and the narrow-line region, and to measure the jet speed close to the jet base, before environmental effects become important. We find one-sided parsec-scale jet structures in Mrk 348, Mrk 231, NGC 4151, and NGC 5506 using VLBI, and we measure low jet speeds (typically = 2 × 105 cm-3 assuming a path length of 0.1 pc, typical of that expected at the inner edge of the obscuring torus.

  6. NEAR-INFRARED SPECTROSCOPY OF NEARBY SEYFERT GALAXIES: IS THERE EVIDENCE FOR SHOCK EXCITATION IN NARROW-LINE REGIONS?

    Energy Technology Data Exchange (ETDEWEB)

    Terao, K. [Graduate School of Science and Engineering, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Nagao, T.; Toba, Y. [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Hashimoto, T. [National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan (China); Yanagisawa, K. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Honjo 3037-5, Kamogata-cho, Asaguchi, Okayama 719-0232 (Japan); Matsuoka, K. [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Ikeda, H. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo, 181-8588 (Japan); Taniguchi, Y., E-mail: terao@cosmos.phys.sci.ehime-u.ac.jp [The Open University of Japan, Wakaba 2-11, Mihama-ku, Chiba 261-8586 (Japan)

    2016-12-20

    One of the important unsettled problems regarding active galactic nuclei (AGNs) is the major ionization mechanism of gas clouds in AGN narrow-line regions (NLRs). In order to investigate this issue, we present our J -band spectroscopic observations of a sample of 26 nearby Seyfert galaxies. In our study, we use the flux ratio of the following two forbidden emission lines, [Fe ii]1.257  μ m and [P ii]1.188  μ m, because it is known that this ratio is sensitive to the ionization mechanism. We obtain the [Fe ii]/[P ii] flux ratio or its lower limit for 19 objects. In addition to our data, we compile this flux ratio (or its lower limit) for 23 nearby Seyfert galaxies from the literature. Based on the collected data, we find that three Seyfert galaxies show very large lower limits of the [Fe ii]/[P ii] flux ratios (≳10): NGC 2782, NGC 5005, and Mrk 463. It is thus suggested that the contribution of the fast shock in the gas excitation is significantly large for them. However, more than half of the Seyfert galaxies in our sample show moderate [Fe ii]/[P ii] flux ratios (∼2), which is consistent with pure photoionization by power-law ionizing continuum emission. We also find that the [Fe ii]/[P ii] flux ratio shows no clear correlation with the radio loudness, suggesting that the radio jet is not the primary origin of shocks in NLRs of Seyfert galaxies.

  7. Evidence for an Ionized Accretion Disk in the Seyfert 2 Galaxy NGC 1068

    Science.gov (United States)

    Colbert, E. J. M.; Weaver, K. A.; Mulchaey, J. S.; Mushotzky, R. F.

    2000-10-01

    We present results from analyses of RXTE, ASCA and BeppoSAX X-ray spectral data from the archetypal Seyfert 2 galaxy NGC 1068. Simultaneous RXTE and ASCA data (spanning 4 - 100 keV) are best fit with a power-law continuum with photon index Γ ~ 1.7 (in agreement with the canonical value for type 1 Seyferts), plus reflection from ionized matter with ξ ~ 1000. Reflection from ionized matter is significantly preferred over reflection from cold matter (Δ χ2 ≈ 50 for 320 dof). When the Fe line complex is modelled with three narrow Gaussians at 6.4, 6.7 and 6.97 keV, we find that the 6.7 keV line flux increases by a factor of ≈ 2 in four months, between the RXTE/ASCA and BeppoSAX observations. Thus we argue that the 6.7 keV line emission comes to us directly from the accretion disk, and not from the electron scattering region further out from the nucleus. We find no evidence for variability in the line fluxes at 6.4 and 6.97 keV. Although ionized accretion disks are thought to be present in NLS1 nuclei, we are only now finding evidence for them in ``broad-line'' Seyfert nuclei (type 1: 1E 1615+061 and type 2: NGC 1068, this work). We shall discuss the implications of these results on the particular geometry required in NGC 1068.

  8. New metallicity calibration for Seyfert 2 galaxies based on the N2O2 index

    Science.gov (United States)

    Castro, C. S.; Dors, O. L.; Cardaci, M. V.; Hägele, G. F.

    2017-05-01

    We derive a new relation between the metallicity of Seyfert 2 active galactic nuclei (AGNs) and the intensity of the narrow emission-lines ratio N2O2 = log([N II] λ6584/[O II] λ3727). The calibration of this relation was performed by determining the metallicity (Z) of a sample of 58 AGNs through a diagram containing the observational data and the results of a grid of photoionization models obtained with the cloudy code. We find the new Z/Z⊙-N2O2 relation using the obtained metallicity values and the corresponding observational emission-line intensities for each object of the sample. Estimations derived through the use of this new calibration indicate that the narrow-line regions of Seyfert 2 galaxies exhibit a large range of metallicities (0.3 ≲ Z/Z⊙ ≲ 2.0), with a median value Z ≈ Z⊙. Regarding the possible existence of correlations between the luminosity L(Hβ), the electron density and the colour excess E(B - V) with the metallicity in this kind of objects, we do not find correlations between them.

  9. Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Guobin; Wang, Tinggui; Yang, Chenwei, E-mail: gbmou@ustc.edu.cn [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei 230026 (China)

    2017-07-20

    The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

  10. Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

    International Nuclear Information System (INIS)

    Mou, Guobin; Wang, Tinggui; Yang, Chenwei

    2017-01-01

    The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

  11. Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

    Science.gov (United States)

    Mou, Guobin; Wang, Tinggui; Yang, Chenwei

    2017-07-01

    The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

  12. The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping

    DEFF Research Database (Denmark)

    Denney, Kelly D.; Bentz, Misty C.; Peterson, Bradley M.

    2006-01-01

    We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Observatory. Cross-correlation analysis of the H_beta emission-line light curve with the optical continuum light curve...... reveals an emission-line time delay of 3.73 (+-0.75) days. By combining this time delay with the H_beta line width, we derive a central black hole mass of M_BH = 9.8(+-2.1)x10^6 M_sun, an improvement in precision of a factor of several over past results....

  13. A catapult model for the narrow-line region in Seyferts and radio galaxies

    International Nuclear Information System (INIS)

    Smith, M.D.

    1984-01-01

    The kinematics and stability of clouds falling radially into a supersonic wind are studied. A critical parameter is found, the ejection coefficient, which separates clouds which continue to gravitate inwards from those which are catapulted out by the ram pressure of the wind. This leads to a maximum size for ejected clouds. The clouds are partially broken up by fluid dynamic instabilities and the fragments expelled with enhanced velocities. This model is applied to the narrow-line region of Seyferts and radio galaxies. A quasi-steady picture may be established for the wind-ambient medium interaction zone. The wind is shocked and escapes through jets or bubbles; the ambient medium cools, forming the clouds which gravitate inwards. (author)

  14. Radio ejection and broad forbidden emission lines in the Seyfert galaxy NGC 7674

    International Nuclear Information System (INIS)

    Unger, S.W.; Pedlar, A.; Axon, D.J.

    1988-01-01

    The Seyfert nucleus in NGC7674 (Mkn533) is remarkable for its broad asymmetric forbidden line profiles, which extend 2000 kms -1 blueward of the systemic velocity. The galaxy also has a compact nuclear radio source. We have obtained new high-resolution radio observations of NGC7674, using the European VLBI network and the VLA, and optical spectroscopic observations using the Isaac Newton Telescope. The radio maps reveal a triple radio source with a total angular extent of about 0.7 arcsec, and provide evidence that the radio emission is powered by collimated ejection. In the plane of the sky, the ejection axis appears roughly perpendicular to the galactic rotation axis. Although the dominant radio components are separated by 0.5 arcsec, the broad [OIII]λ5007 line emission is confined to within about 0.25 arcsec of the continuum nucleus. (author)

  15. Broad-band properties of the CfA Seyfert galaxies. III - Ultraviolet variability

    Science.gov (United States)

    Edelson, R. A.; Pike, G. F.; Krolik, J. H.

    1990-01-01

    A total of 657 archived IUE spectra are used to study the UV variability properties of six members of the CfA Seyfert I galaxy sample. All show strong evidence for continuum and line variations and a tendency for less luminous objects to be more strongly variable. Most objects show a clear correlation at zero lag between UV spectral index and luminosity, evidence that the variable component is an accretion disk around a black hole which is systematically smaller in less luminous sources. No correlation is seen between the continuum luminosity and equivalent width of the C IV, Mg II, and semiforbidden C III emission lines when the entire sample is examined, but a clear anticorrelation is present when only repeated observations of individual objects are considered. This is due to a combination of light-travel time effects in the broad-line region and the nonlinear responses of lines to continuum fluctuations.

  16. REVERBERATION MAPPING MEASUREMENTS OF BLACK HOLE MASSES IN SIX LOCAL SEYFERT GALAXIES

    International Nuclear Information System (INIS)

    Denney, K. D.; Peterson, B. M.; Pogge, R. W.; Atlee, D. W.; Bentz, M. C.; Bird, J. C.; Comins, M. L.; Dietrich, M.; Eastman, J. D.; Adair, A.; Au-Yong, K.; Chisholm, E.; Ewald, S.; Ferbey, S.; Jackson, K.; Brokofsky, D. J.; Gaskell, C. M.; Hedrick, C. H.; Doroshenko, V. T.; Efimov, Y. S.

    2010-01-01

    We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hβ reverberation lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and Hβ emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) R BLR -L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved Hβ time-delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.

  17. Infrared emission in Seyfert 2 galaxies - Reprocessed radiation from a dusty torus?

    Science.gov (United States)

    Storchi-Bergmann, Thaisa; Mulchaey, John S.; Wilson, Andrew S.

    1992-01-01

    New and existing data for a sample of nine Seyfert 2 galaxies with known 'ionization cones' are combined in order to test whether collimation results from shadowing of radiation from a small isotropic nuclear source by a thick dusty torus. The number of ionizing photons emitted by the compact nucleus is calculated from the emission-line ratios measured for gas within the cones. On the assumption that this compact nuclear source radiates isotropically, the optical-UV power incident on the torus, which is expected to be reradiated in the IR, is determined. It is found that the observed IRAS luminosities are consistent with the torus model in eight of the nine objects with sufficient data to perform the calculation. It is concluded that the data are generally consistent with collimation and reradiation by a dusty torus.

  18. Anisotropic ionizing radiation in Seyfert galaxies. I - The extended narrow-line region in Markarian 573

    Science.gov (United States)

    Tsvetanov, Zlatan; Walsh, J. R.

    1992-01-01

    The morphology, kinematics, and ionization state of the nuclear extended narrow-line region (ENLR) of the Seyfert 2 galaxy Mrk 573 are studied using narrow-band images of a grid of long-slit spectra. The entire ENLR is mapped spectroscopically, and velocity structure is studied. The velocity field map shows a typical galactic rotation picture with some important deviations. A simple geometric model, in accordance with the 'unified schemes', is employed to study the effects of various parameters of the observed picture. The best match is achieved when a biconical radiation field illuminates the ISM of the host galaxy that takes part in a normal galaxy rotation but also has radial motions close to the nucleus. The emission-line images reveal an ENLR elongated along the radio axis in the northwest-southeast direction, but a map of the flux ratio forbidden O III 5007/(H-alpha + forbidden N II) shows a different structure, with the highest excitation peak offset by about 4 arcsec along the radio axis to the southeast.

  19. The host galaxy of the gamma-ray narrow-line Seyfert 1 galaxy 1H 0323+342

    Energy Technology Data Exchange (ETDEWEB)

    León Tavares, J.; Chavushyan, V.; Puerari, I.; Patiño-Alvarez, V.; Carramiñana, A.; Carrasco, L.; Guichard, J.; Olguín-Iglesias, A.; Valdes, J. [Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE), Apartado Postal 51 y 216, 72000 Puebla (Mexico); Kotilainen, J. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland); Añorve, C. [Facultad de Ciencias de la Tierra y del Espacio (FACITE) de la Universidad Autónoma de Sinaloa, Blvd. de la Americas y Av. Universitarios S/N, Ciudad Universitaria, C.P. 80010, Culiacán Sinaloa (Mexico); Cruz-González, I. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ap. 70-264, 04510 DF (Mexico); Antón, S. [Instituto de Astrofísica de Andalucía-CSIC, E-18008 Granada (Spain); Karhunen, K.; Sanghvi, J., E-mail: leon.tavares@inaoep.mx [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-20100 Turku (Finland)

    2014-11-01

    We present optical and near-infrared (NIR) imaging data of the radio-loud, narrow-line Seyfert 1 galaxy 1H 0323+342, which shows intense and variable gamma-ray activity discovered by the Fermi satellite with the Large Area Telescope. Near-infrared and optical images are used to investigate the structural properties of the host galaxy of 1H 0323+342; this together with optical spectroscopy allows us to examine its black hole mass. Based on two-dimensional (2D) multiwavelength surface-brightness modeling, we find that statistically, the best model fit is a combination of a nuclear component and a Sérsic profile (n ∼ 2.8). However, the presence of a disk component (with a small bulge n ∼ 1.2) also remains a possibility and cannot be ruled out with the present data. Although at first glance a spiral-arm-like structure is revealed in our images, a 2D Fourier analysis of the imagery suggests that this structure corresponds to an asymmetric ring, likely associated with a recent violent dynamical interaction. We discuss our results in the context of relativistic jet production and galaxy evolution.

  20. A SAMPLE OF SEYFERT-2 GALAXIES WITH ULTRALUMINOUS GALAXY-WIDE NARROW-LINE REGIONS: QUASAR LIGHT ECHOES?

    International Nuclear Information System (INIS)

    Schirmer, M.; Diaz, R.; Levenson, N. A.; Winge, C.; Holhjem, K.

    2013-01-01

    We report the discovery of Seyfert-2 galaxies in SDSS-DR8 with galaxy-wide, ultraluminous narrow-line regions (NLRs) at redshifts z = 0.2-0.6. With a space density of 4.4 Gpc –3 at z ∼ 0.3, these 'green beans' (GBs) are amongst the rarest objects in the universe. We are witnessing an exceptional and/or short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). The main focus of this paper is on a detailed analysis of the GB prototype galaxy J2240–0927 (z = 0.326). Its NLR extends over 26 × 44 kpc and is surrounded by an extended NLR. With a total [O III] λ5008 luminosity of (5.7 ± 0.9) × 10 43 erg s –1 , this is one of the most luminous NLRs known around any type-2 galaxy. Using VLT/XSHOOTER, we show that the NLR is powered by an AGN, and we derive resolved extinction, density, and ionization maps. Gas kinematics is disturbed on a global scale, and high-velocity outflows are absent or faint. This NLR is unlike any other NLR or extended emission line region known. Spectroscopy with Gemini/GMOS reveals extended, high-luminosity [O III] emission also in other GBs. WISE 24 μm luminosities are 5-50 times lower than predicted by the [O III] fluxes, suggesting that the NLRs reflect earlier, very active quasar states that have strongly subsided in less than a galaxy's light-crossing time. These light echoes, or ionization echoes, are about 100 times more luminous than any other such echo known to date. X-ray data are needed for photoionization modeling and to verify the light echoes.

  1. Large-Scale Environment Properties of Narrow-Line Seyfert 1 Galaxies at z < 0.4

    Energy Technology Data Exchange (ETDEWEB)

    Järvelä, Emilia [Metsähovi Radio Observatory, Aalto University, Espoo (Finland); Department of Electronics and Nanoengineering, Aalto University, Espoo (Finland); Lähteenmäki, A. [Metsähovi Radio Observatory, Aalto University, Espoo (Finland); Department of Electronics and Nanoengineering, Aalto University, Espoo (Finland); Tartu Observatory, Tõravere (Estonia); Lietzen, H., E-mail: emilia.jarvela@aalto.fi [Tartu Observatory, Tõravere (Estonia)

    2017-11-30

    The large-scale environment is believed to affect the evolution and intrinsic properties of galaxies. It offers a new perspective on narrow-line Seyfert 1 galaxies (NLS1) which have not been extensively studied in this context before. We study a large and diverse sample of 960 NLS1 galaxies using a luminosity-density field constructed using Sloan Digital Sky Survey. We investigate how the large-scale environment is connected to the properties of NLS1 galaxies, especially their radio loudness. Furthermore, we compare the large-scale environment properties of NLS1 galaxies with other active galactic nuclei (AGN) classes, for example, other jetted AGN and broad-line Seyfert 1 (BLS1) galaxies, to shed light on their possible relations. In general NLS1 galaxies reside in less dense large-scale environments than any of our comparison samples, thus supporting their young age. The average luminosity-density and distribution to different luminosity-density regions of NLS1 sources is significantly different compared to BLS1 galaxies. This contradicts the simple orientation-based unification of NLS1 and BLS1 galaxies, and weakens the hypothesis that BLS1 galaxies are the parent population of NLS1 galaxies. The large-scale environment density also has an impact on the intrinsic properties of NLS1 galaxies; the radio loudness increases with the increasing luminosity-density. However, our results suggest that the NLS1 population is indeed heterogeneous, and that a considerable fraction of them are misclassified. We support a suggested description that the traditional classification based on the radio loudness should be replaced with the division to jetted and non-jetted sources.

  2. A FANAROFF-RILEY TYPE I CANDIDATE IN NARROW-LINE SEYFERT 1 GALAXY Mrk 1239

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Wajima, Kiyoaki [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong, Daejeon 305-348 (Korea, Republic of); Hagiwara, Yoshiaki [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Inoue, Makoto, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2015-01-10

    We report finding kiloparsec-scale radio emissions aligned with parsec-scale jet structures in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 1239 using the Very Large Array and the Very Long Baseline Array. Thus, this radio-quiet NLS1 has a jet-producing central engine driven by essentially the same mechanism as that of other radio-loud active galactic nuclei (AGNs). Most of the radio luminosity is concentrated within 100 parsecs and overall radio morphology looks edge-darkened; the estimated jet kinetic power is comparable to Fanaroff-Riley Type I radio galaxies. The conversion from accretion to jet power appears to be highly inefficient in this highly accreting low-mass black hole system compared with that in a low-luminosity AGN with similar radio power driven by a sub-Eddington, high-mass black hole. Thus, Mrk 1239 is a crucial probe to the unexplored parameter spaces of central engines for a jet formation.

  3. THE MOLECULAR WIND IN THE NEAREST SEYFERT GALAXY CIRCINUS REVEALED BY ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Zschaechner, Laura K.; Walter, Fabian; Farina, Emanuele P.; Kruijssen, J. M. Diederik [Max Planck Institute für Astronomie—Königstuhl 17, D-69117 Heidelberg (Germany); Bolatto, Alberto; Veilleux, Sylvain [Department of Astronomy and Joint Space Science Institute, University of Maryland, College Park, MD 20642 (United States); Leroy, Adam [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Meier, David S. [Department of Physics, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 (United States); Ott, Jürgen, E-mail: zschaechner@mpia.de [National Radio Astronomy Observatory—P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States)

    2016-12-01

    We present ALMA observations of the inner 1′ (1.2 kpc) of the Circinus galaxy, the nearest Seyfert. We target CO (1–0) in the region associated with a well-known multiphase outflow driven by the central active galactic nucleus (AGN). While the geometry of Circinus and its outflow make disentangling the latter difficult, we see indications of outflowing molecular gas at velocities consistent with the ionized outflow. We constrain the mass of the outflowing molecular gas to be 1.5 × 10{sup 5}−5.1 × 10{sup 6} M {sub ⊙}, yielding a molecular outflow rate of 0.35–12.3 M {sub ⊙} yr{sup −1}. The values within this range are comparable to the star formation (SF) rate in Circinus, indicating that the outflow indeed regulates SF to some degree. The molecular outflow in Circinus is considerably lower in mass and energetics than previously studied AGN-driven outflows, especially given its high ratio of AGN luminosity to bolometric luminosity. The molecular outflow in Circinus is, however, consistent with some trends put forth by Cicone et al., including a linear relation between kinetic power and AGN luminosity, as well as its momentum rate versus bolometric luminosity (although the latter places Circinus among the starburst galaxies in that sample). We detect additional molecular species including CN and C{sup 17}O.

  4. Outflows in the narrow-line region of bright Seyfert galaxies - I. GMOS-IFU data

    Science.gov (United States)

    Freitas, I. C.; Riffel, R. A.; Storchi-Bergmann, T.; Elvis, M.; Robinson, A.; Crenshaw, D. M.; Nagar, N. M.; Lena, D.; Schmitt, H. R.; Kraemer, S. B.

    2018-05-01

    We present two-dimensional maps of emission-line fluxes and kinematics, as well as of the stellar kinematics of the central few kpc of five bright nearby Seyfert galaxies - Mrk 6, Mrk 79, Mrk 348, Mrk 607, and Mrk 1058 - obtained from observations with the Gemini Multi-Object Spectrograph Integral Field Unit on the Gemini North Telescope. The data cover the inner 3.5 arcsec × 5.0 arcsec - corresponding to physical scales in the range 0.6 × 0.9-1.5 × 2.2 kpc2 - at a spatial resolution ranging from 110 to 280 pc with a spectral coverage of 4300-7100 Å and velocity resolution of ≈90 km s-1. The gas excitation is Seyfert like everywhere but show excitation gradients that are correlated with the gas kinematics, reddening and/or the gas density. The gas kinematics show in all cases two components: a rotation one similar to that observed in the stellar velocity field, and an outflow component. In the case of Mrk607, the gas is counter-rotating relative to the stars. Enhanced gas velocity dispersion is observed in association with the outflows according to two patterns: at the locations of the highest outflow velocities along the ionization axis or perpendicularly to it in a strip centred at the nucleus that we attribute to an equatorial outflow. Bipolar outflows are observed in Mrk 348 and Mrk 79, while in Mrk 1058 only the blueshifted part is clearly observed, while in cases of Mrk 6 and Mrk 607, the geometry of the outflow needs further constraints from modelling to be presented in a forthcoming study, where the mass flow rate and powers will also be obtained.

  5. CORRELATION ANALYSIS OF A LARGE SAMPLE OF NARROW-LINE SEYFERT 1 GALAXIES: LINKING CENTRAL ENGINE AND HOST PROPERTIES

    International Nuclear Information System (INIS)

    Xu Dawei; Komossa, S.; Wang Jing; Yuan Weimin; Zhou Hongyan; Lu Honglin; Li Cheng; Grupe, Dirk

    2012-01-01

    We present a statistical study of a large, homogeneously analyzed sample of narrow-line Seyfert 1 (NLS1) galaxies, accompanied by a comparison sample of broad-line Seyfert 1 (BLS1) galaxies. Optical emission-line and continuum properties are subjected to correlation analyses, in order to identify the main drivers of the correlation space of active galactic nuclei (AGNs), and of NLS1 galaxies in particular. For the first time, we have established the density of the narrow-line region as a key parameter in Eigenvector 1 space, as important as the Eddington ratio L/L Edd . This is important because it links the properties of the central engine with the properties of the host galaxy, i.e., the interstellar medium (ISM). We also confirm previously found correlations involving the line width of Hβ and the strength of the Fe II and [O III] λ5007 emission lines, and we confirm the important role played by L/L Edd in driving the properties of NLS1 galaxies. A spatial correlation analysis shows that large-scale environments of the BLS1 and NLS1 galaxies of our sample are similar. If mergers are rare in our sample, accretion-driven winds, on the one hand, or bar-driven inflows, on the other hand, may account for the strong dependence of Eigenvector 1 on ISM density.

  6. Galaxies

    International Nuclear Information System (INIS)

    1981-01-01

    Normal galaxies, radio galaxies, and Seyfert galaxies are considered. The large magellanic cloud and the great galaxy in Andromedia are highlighted. Quasars and BL lacertae objects are also discussed and a review of the spectral observations of all of these galaxies and celestial objects is presented

  7. KILOPARSEC-SCALE JETS IN THREE RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Joseph L.; Lister, Matthew L., E-mail: jlr@purdue.edu [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

    2015-02-10

    We have discovered kiloparsec-scale extended radio emission in three narrow-line Seyfert 1 galaxies (NLS1s) in sub-arcsecond resolution 9 GHz images from the Karl G. Jansky Very Large Array. We find all sources show two-sided, mildly core-dominated jet structures with diffuse lobes dominated by termination hotspots. These span 20–70 kpc with morphologies reminiscent of FR II radio galaxies, while the extended radio luminosities are intermediate between FR I and FR II sources. In two cases the structure is linear, while a 45° bend is apparent in the third. Very Long Baseline Array images at 7.6 GHz reveal parsec-scale jet structures, in two cases with extended structure aligned with the inner regions of the kiloparsec-scale jets. Based on this alignment, the ratio of the radio core–luminosity to the optical luminosity, the jet/counter-jet intensity and extension length ratios, and moderate core brightness temperatures (≲10{sup 10} K), we conclude these jets are mildly relativistic (β≲0.3, δ∼1−1.5) and aligned at moderately small angles to the line of sight (10–15°). The derived kinematic ages of ∼10{sup 6}–10{sup 7} yr are much younger than radio galaxies but comparable to other NLS1s. Our results increase the number of radio-loud NLS1s with known kiloparsec-scale extensions from 7 to 10 and suggest that such extended emission may be common, at least among the brightest of these sources.

  8. FAR-INFRARED LINE SPECTRA OF SEYFERT GALAXIES FROM THE HERSCHEL-PACS SPECTROMETER

    International Nuclear Information System (INIS)

    Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma; Dasyra, Kalliopi M.; Calzoletti, Luca; Malkan, Matthew A.; Tommasin, Silvia

    2015-01-01

    We observed the far-IR fine-structure lines of 26 Seyfert galaxies with the Herschel-PACS spectrometer. These observations are complemented with Spitzer Infrared Spectrograph and Herschel SPIRE spectroscopy. We used the ionic lines to determine electron densities in the ionized gas and the [C I] lines, observed with SPIRE, to measure the neutral gas densities, while the [O I] lines measure the gas temperature, at densities below ∼10 4  cm –3 . Using the [O I]145 μm/63 μm and [S III]33/18 μm line ratios, we find an anti-correlation of the temperature with the gas density. Various fine-structure line ratios show density stratifications in these active galaxies. On average, electron densities increase with the ionization potential of the ions. The infrared lines arise partly in the narrow line region, photoionized by the active galactic nucleus (AGN), partly in H II regions photoionized by hot stars, and partly in photo-dissociated regions. We attempt to separate the contributions to the line emission produced in these different regions by comparing our observed emission line ratios to theoretical values. In particular, we tried to separate the contribution of AGNs and star formation by using a combination of Spitzer and Herschel lines, and we found that besides the well-known mid-IR line ratios, the line ratio of [O III]88 μm/[O IV]26 μm can reliably discriminate the two emission regions, while the far-IR line ratio of [C II]157 μm/[O I]63 μm is only able to mildly separate the two regimes. By comparing the observed [C II]157 μm/[N II]205 μm ratio with photoionization models, we also found that most of the [C II] emission in the galaxies we examined is due to photodissociation regions

  9. KILOPARSEC-SCALE RADIO STRUCTURES IN NARROW-LINE SEYFERT 1 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Akihiro; Kino, Motoki [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Nagira, Hiroshi [Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8512 (Japan); Kawakatu, Nozomu [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Nagai, Hiroshi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Asada, Keiichi, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2012-11-20

    We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters of the Very Large Array, which increases the number of known radio-loud NLS1s with kpc-scale structures to six, including two {gamma}-ray-emitting NLS1s (PMN J0948+0022 and 1H 0323+342) detected by the Fermi Gamma-ray Space Telescope. The detection rate of extended radio emissions in NLS1s is lower than that in broad-line active galactic nuclei (AGNs) with a statistical significance. We found both core-dominated (blazar-like) and lobe-dominated (radio-galaxy-like) radio structures in these six NLS1s, which can be understood in the framework of the unified scheme of radio-loud AGNs that considers radio galaxies as non-beamed parent populations of blazars. Five of the six NLS1s have (1) extended radio luminosities suggesting jet kinetic powers of {approx}> 10{sup 44} erg s{sup -1}, which is sufficient to make jets escape from hosts' dense environments; (2) black holes of {approx}> 10{sup 7} M {sub Sun }, which can generate the necessary jet powers from near-Eddington mass accretion; and (3) two-sided radio structures at kpc scales, requiring expansion rates of {approx}0.01c-0.3c and kinematic ages of {approx}> 10{sup 7} years. On the other hand, most typical NLS1s would be driven by black holes of {approx}< 10{sup 7} M {sub Sun} in a limited lifetime of {approx}10{sup 7} years. Hence, the kpc-scale radio structures may originate in a small window of opportunity during the final stage of the NLS1 phase just before growing into broad-line AGNs.

  10. BROAD-LINE REVERBERATION IN THE KEPLER-FIELD SEYFERT GALAXY Zw 229-015

    International Nuclear Information System (INIS)

    Barth, Aaron J.; Nguyen, My L.; Malkan, Matthew A.; Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Choi, Jieun; Duchene, Gaspard; Ganeshalingam, Mohan; Gorjian, Varoujan; Joner, Michael D.; Bennert, Vardha Nicola; Botyanszki, Janos; Childress, Michael; Cucciara, Antonino; Comerford, Julia M.; Da Silva, Robert; Fumagalli, Michele; Gates, Elinor L.; Gerke, Brian F.

    2011-01-01

    The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from Hβ reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad Hβ flux. From cross-correlation measurements, we find that the Hβ light curve has a rest-frame lag of 3.86 +0.69 -0.90 days with respect to the V-band continuum variations. We also measure reverberation lags for Hα and Hγ and find an upper limit to the Hδ lag. Combining the Hβ lag measurement with a broad Hβ width of σ line = 1590 ± 47 km s -1 measured from the rms variability spectrum, we obtain a virial estimate of M BH = 1.00 +0.19 -0.24 x 10 7 M sun for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

  11. NGC 985 - Extended ionized regions and the far-infrared luminosity of a ring-shaped Seyfert galaxy

    International Nuclear Information System (INIS)

    Rodriguez Espinosa, J.M.; Stanga, R.M.

    1990-01-01

    Narrow-band H-alpha images and long-slit spectroscopy of the Seyfert galaxy NGC 985 are presented. Large-scale extended ionized zones are seen to cover a significant fraction of the ring of this object. These ionized zones are responsible for a considerable fraction (greater than 35 percent) of the far-infrared emission of NGC 985. These ionized zones are interpreted as giant H II region complexes, formed in a recent burst of star formation. It is also argued that that starburst was triggered by a galaxy interaction. 41 refs

  12. Modeling time delays in the X-ray spectrum of the Seyfert galaxy MCG-6-30-15

    Czech Academy of Sciences Publication Activity Database

    Goosmann, René; Czerny, B.; Karas, Vladimír; Ponti, G.

    2007-01-01

    Roč. 466, č. 3 (2007), s. 865-873 ISSN 0004-6361 R&D Projects: GA MŠk(CZ) LC06014; GA AV ČR IAA300030510 Grant - others:GAUK(CZ) GAUK 299/2004; EU(XE) ESA-PECS project No. 98040 Institutional research plan: CEZ:AV0Z10030501 Source of funding: V - iné verejné zdroje Keywords : accretion disks * galaxie s: Seyfert * active galaxie s * radiative transfer Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.259, year: 2007

  13. Radio jets and gamma-ray emission in radio-silent narrow-line Seyfert 1 galaxies

    Science.gov (United States)

    Lähteenmäki, A.; Järvelä, E.; Ramakrishnan, V.; Tornikoski, M.; Tammi, J.; Vera, R. J. C.; Chamani, W.

    2018-06-01

    We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect. The detections are a plausible indicator of the presence of a powerful, most likely relativistic jet because this intensity of emission at 37 GHz cannot be explained by, for example, radiation from supernova remnants. Additionally, one of the detected NLS1 galaxies is a newly discovered source of gamma rays and three others are candidates for future detections. 37 GHz data are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/L1

  14. Exploring the physics of the accretion and jet in nearby narrow-line Seyfert 1 galaxies

    Science.gov (United States)

    Yao, Su; Qiao, Erlin; Wu, Xue-Bing; You, B.

    2018-06-01

    In this paper, we explore the physics of the accretion and jet in narrow-line Seyfert 1 (NLS1) galaxy. Specifically, we compile a sample composed of 16 nearby NLS1 with Lbol/LEdd ≳ 0.1. We investigate the mutual correlation between their radio luminosity LR, X-ray luminosity LX, optical luminosity L5100, and black hole mass MBH. By adopting partial correlation analysis, we find (1) a positive correlation between LX and MBH and (2) a weak positive correlation between LR and L5100. However, we don't find significant correlations between LR and LX or between LX and L5100 after considering the effect of the black hole mass, which leads to a finding that LX/LEdd is independent of L5100/LEdd. Interestingly, the findings that LX is correlated with MBH and LX/LEdd is not correlated with L5100/LEdd support that the X-ray emission is saturated with increasing \\dot{M} for Lbol/LEdd ≳ 0.1 in NLS1, which may be understood in the framework of slim disc scenario. Finally, we suggest that a larger NLS1 sample with high-quality radio and X-ray data is needed to further confirm this result in the future.

  15. X-ray evidence for ultra-fast outflows in Seyfert galaxies

    Science.gov (United States)

    Tombesi, Francesco; Braito, Valentina; Reeves, James; Cappi, Massimo; Dadina, Mauro

    2012-07-01

    X-ray evidence for massive, highly ionized, ultra-fast outflows (UFOs) has been recently reported in a number of AGNs through the detection of blue-shifted Fe XXV/XXVI absorption lines. We present the results of a comprehensive spectral analysis of a large sample of 42 local Seyferts observed with XMM-Newton. Similar results are also obtained from a Suzaku analysis of 5 radio galaxies. We find that UFOs are common phenomena, being present in >40% of the sources. Their outflow velocity distribution is in the range ˜0.03--0.3c, with mean value of ˜0.14c. The ionization parameter is very high, in the range logξ˜3--6 erg~s^{-1}~cm, and the associated column densities are also large, in the range ˜10^{22}--10^{24} cm^{-2}. Their location is constrained at ˜0.0003--0.03pc (˜10^2--10^4 r_s) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are in the interval ˜0.01--1M_{⊙}~yr^{-1}. The associated mechanical power is also high, in the range ˜10^{43}--10^{45} erg/s, which indicates that UFOs are capable to provide a significant contribution to the AGN cosmological feedback.

  16. SBS 0846+513: a New Gamma-ray Emitting Narrow-line Seyfert 1 Galaxy

    Science.gov (United States)

    D'Ammando, F.; Orienti, M.; Finke, J.; Raiteri, C. M.; Angelakis, E.; Fuhrmann, L.; Giroletti, M.; Hovatta, T.; Max-Moerbeck, W.; Perkins, J. S.; hide

    2012-01-01

    We report Fermi-LAT observations of the radio-loud AGN SBS 0846+513 (z=0.5835), optically classified as a Narrow-Line Seyfert 1 galaxy, together with new and archival radio-to-X-ray data. The source was not active at ?-ray energies during the first two years of Fermi operation. A significant increase in activity was observed during 2010 October-2011 August. In particular a strong gamma-ray flare was observed in 2011 June reaching an isotropic ?-ray luminosity (0.1-300 GeV) of 1.0×10(sup 48) erg s(sup -1), comparable to that of the brightest flat spectrum radio quasars, and showing spectral evolution in gamma rays. An apparent superluminal velocity of (8.2+/-1.5)c in the jet was inferred from 2011-2012 VLBA images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indications of the presence of a relativistic jet as powerful as those of blazars. In addition, variability and spectral properties in radio and gamma-ray bands indicate blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazar's black hole mass distribution.

  17. Multi-wavelength study of the Seyfert 1 galaxy NGC 3783 with XMM-Newton

    CERN Document Server

    Blustin, A J; Behar, E; Kaastra, J S; Kahn, S M; Page, M J; Sako, M; Steenbrugge, K C

    2002-01-01

    We present the analysis of multi-wavelength XMM-Newton data from the Seyfert galaxy NGC 3783, including UV imaging, X-ray and UV lightcurves, the 0.2-10 keV X-ray continuum, the iron K-alpha emission line, and high-resolution spectroscopy and modelling of the soft X-ray warm absorber. The 0.2-10 keV spectral continuum can be well reproduced by a power-law at higher energies; we detect a prominent Fe K-alpha emission line, with both broad and narrow components, and a weaker emission line at 6.9 keV which is probably a combination of Fe K-beta and Fe XXVI. We interpret the significant deficit of counts in the soft X-ray region as being due to absorption by ionised gas in the line of sight. This is demonstrated by the large number of narrow absorption lines in the RGS spectrum from iron, oxygen, nitrogen, carbon, neon, argon, magnesium, silicon and sulphur. The wide range of iron states present in the spectrum enables us to deduce the ionisation structure of the absorbing medium. We find that our spectrum contai...

  18. Variability of the soft excess in the Seyfert I galaxy Mkn 335

    International Nuclear Information System (INIS)

    Turner, T.J.; Pounds, K.A.

    1988-01-01

    The luminous Seyfert 1 galaxy Mkn 335 was observed by EXOSAT on six occasions between 1983 November 5 and 1985 December 24. A previous analysis of the 1984 December 6 observation revealed a two-component spectrum, with a hard power law dominant above ∼ 2 keV on which was superimposed a strong soft X-ray excess in the 0.1-2 keV band of the EXOSAT low-energy (LE) detectors. The hard X-ray component was seen to vary strongly over time-scales of 1-2 hr in this 1984 observation. The more recent observations of Mkn 335, reported here, have shown the soft spectral excess to be a persistent feature, and the continuing presence of rapid variability in the hard X-ray component. An extended observation on 1985 July 21-22 has also revealed a strong variation in the LE band on a time-scale of ∼ 10 hr. This is the first report of distinctive short-term variability in the soft X-ray excess of an AGN, strengthening its proposed identification with the thermal emission from an accretion disc. (author)

  19. SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

    International Nuclear Information System (INIS)

    Shapovalova, A. I.; Burenkov, A. N.; Popović, L. Č.; Kovačević, J.; Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L.; Ilić, D.; Kovačević, A.; Kollatschny, W.; Bochkarev, N. G.; León-Tavares, J.; Mercado, A.; Benítez, E.; Dultzin, D.; De la Fuente, E.

    2012-01-01

    We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted Hα, Hβ, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the Hβ and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F max /F min ) of Ark 564 is between 1.5 for Hα and 1.8 for the Fe II lines. The correlation between the Fe II and Hβ flux variations is of higher significance than that of Hα and Hβ (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

  20. Broad-band properties of the CfA Seyfert Galaxies. II - Infrared to millimeter properties

    Science.gov (United States)

    Edelson, R. A.; Malkan, M. A.; Rieke, G. H.

    1987-01-01

    IR and mm observations of the 48 Seyfert 1 and 2 galaxies (SG1s and SG2s) of the CfA sample (Huchra and Berg, 1987) are reported. Data obtained (1) in the NIR using the 1.55-m reflector at Stewart Observatory and the 3-m IRTF during 1984-1986, (2) in the FIR with IRAS, and (3) at 1.3 mm using the 12-m NRAO telescope at KPNO in June 1984 are presented in extensive tables and graphs and characterized in detail. None of the objects was detected at 1.3 mm, and the IR spectra of the SG2s are found to be significantly steeper (indicating thermal emission) than those of SG1s and QSOs (nonthermal emission). Turnover in the IR emission below 100 microns (in half of the objects detected at three or more IRAS wavelengths) is shown to be consistent with an accretion disk in dust-free SG1s and with unusually warm (35-65 K) dust in SG2s. It is inferred that a 60-100-micron cool excess is masking turnover in the other SGs, so that a general association of SG nuclei with strong star formation can be confirmed.

  1. The peculiar radio-loud narrow line Seyfert 1 galaxy 1H 0323+342

    Energy Technology Data Exchange (ETDEWEB)

    Paliya, Vaidehi S.; Stalin, C. S. [Indian Institute of Astrophysics, Block-II, Koramangala, Bangalore-560034 (India); Sahayanathan, S. [Astrophysical Science Division, Bhabha Atomic Research Center, Mumbai-400085 (India); Parker, M. L.; Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Anjum, Ayesha [Department of Physics, Christ University, Bangalore-560029 (India); Pandey, S. B., E-mail: vaidehi@iiap.res.in [Aryabhatta Research Institute of Observational Sciences, Manora peak, Nainital-263129 (India)

    2014-07-10

    We present a multiwavelength study of the radio-loud narrow-line Seyfert 1 galaxy (NLSy1) 1H 0323+342, detected by the Fermi Gamma-Ray Space Telescope. Multiband light curves show many orphan X-ray and optical flares having no corresponding γ-ray counterparts. Such anomalous variability behavior can be due to different locations of the emission region from the central source. During a large flare, a γ-ray flux doubling timescale as small as ∼3 hr is noticed. We built spectral energy distributions (SEDs) during different activity states and modeled them using a one-zone leptonic model. The shape of the optical/UV component of the SEDs is dominated by accretion disk emission in all the activity states. In the X-ray band, significant thermal emission from the hot corona is inferred during quiescent and first flaring states; however, during subsequent flares, the nonthermal jet component dominates. The γ-ray emission in all the states can be well explained by inverse-Compton scattering of accretion disk photons reprocessed by the broad-line region. The source showed violent intra-night optical variability, coinciding with one of the high γ-ray activity states. An analysis of the overall X-ray spectrum fitted with an absorbed power-law plus relativistic reflection component hints at the presence of an Fe Kα line and returns a high black hole spin value of a = 0.96 ± 0.14. We argue that 1H 0323+342 possesses dual characteristics, akin to both flat-spectrum radio quasars (FSRQs) and radio-quiet NLSy1 galaxies, though at a low jet power regime compared to powerful FSRQs.

  2. THE RADIO PROPERTIES OF RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES ON PARSEC SCALES

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Minfeng; Chen, Yongjun; Shen, Zhiqiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China); Komossa, S.; Zensus, J. A. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Yuan, Weimin [Key Lab for Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Wajima, Kiyoaki [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong, Daejeon 305-348 (Korea, Republic of); Zhou, Hongyan, E-mail: gumf@shao.ac.cn [Polar Research Institute of China, 451 Jinqiao Road, Shanghai 200136 (China)

    2015-11-15

    We present the detection of the compact radio structures of 14 radio-loud narrow-line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array (VLBA) observations at 5 GHz performed in 2013. While 50% of the sources of our sample show a compact core only, the remaining 50% exhibit a core-jet structure. The measured brightness temperatures of the cores range from 10{sup 8.4} to 10{sup 11.4} K with a median value of 10{sup 10.1} K, indicating that the radio emission is from non-thermal jets, and that, likely, most sources are not strongly beamed, thus implying a low jet speed in these radio-loud NLS1 galaxies. In combination with archival data taken at multiple frequencies, we find that seven sources show flat or even inverted radio spectra, while steep spectra are revealed in the remaining seven objects. Although all of these sources are very radio-loud with R > 100, their jet properties are diverse in terms of their milliarcsecond (mas) scale (parsec scale) morphology and their overall radio spectral shape. The evidence for slow jet speeds (i.e., less relativistic jets), in combination with the low kinetic/radio power, may offer an explanation for the compact VLBA radio structure in most sources. The mildly relativistic jets in these high accretion rate systems are consistent with a scenario where jets are accelerated from the hot corona above the disk by the magnetic field and the radiation force of the accretion disk. Alternatively, a low jet bulk velocity can be explained by low spin in the Blandford–Znajek mechanism.

  3. FAR-INFRARED LINE SPECTRA OF SEYFERT GALAXIES FROM THE HERSCHEL-PACS SPECTROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma [Istituto di Astrofisica e Planetologia Spaziali, INAF, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Dasyra, Kalliopi M. [Observatoire de Paris, LERMA (CNRS:UMR8112), 61 Av. de l' Observatoire, F-75014, Paris (France); Calzoletti, Luca [Agenzia Spaziale Italiana (ASI) Science Data Center, I-00044 Frascati (Roma) (Italy); Malkan, Matthew A. [Astronomy Division, University of California, Los Angeles, CA 90095-1547 (United States); Tommasin, Silvia, E-mail: luigi.spinoglio@iaps.inaf.it [Weizmann Institute of Science, Department of Neurobiology, Rehovot 76100 (Israel)

    2015-01-20

    We observed the far-IR fine-structure lines of 26 Seyfert galaxies with the Herschel-PACS spectrometer. These observations are complemented with Spitzer Infrared Spectrograph and Herschel SPIRE spectroscopy. We used the ionic lines to determine electron densities in the ionized gas and the [C I] lines, observed with SPIRE, to measure the neutral gas densities, while the [O I] lines measure the gas temperature, at densities below ∼10{sup 4} cm{sup –3}. Using the [O I]145 μm/63 μm and [S III]33/18 μm line ratios, we find an anti-correlation of the temperature with the gas density. Various fine-structure line ratios show density stratifications in these active galaxies. On average, electron densities increase with the ionization potential of the ions. The infrared lines arise partly in the narrow line region, photoionized by the active galactic nucleus (AGN), partly in H II regions photoionized by hot stars, and partly in photo-dissociated regions. We attempt to separate the contributions to the line emission produced in these different regions by comparing our observed emission line ratios to theoretical values. In particular, we tried to separate the contribution of AGNs and star formation by using a combination of Spitzer and Herschel lines, and we found that besides the well-known mid-IR line ratios, the line ratio of [O III]88 μm/[O IV]26 μm can reliably discriminate the two emission regions, while the far-IR line ratio of [C II]157 μm/[O I]63 μm is only able to mildly separate the two regimes. By comparing the observed [C II]157 μm/[N II]205 μm ratio with photoionization models, we also found that most of the [C II] emission in the galaxies we examined is due to photodissociation regions.

  4. SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

    Energy Technology Data Exchange (ETDEWEB)

    Shapovalova, A. I.; Burenkov, A. N. [Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167 (Russian Federation); Popovic, L. C.; Kovacevic, J. [Astronomical Observatory, Volgina 7, 11160 Belgrade 74 (Serbia); Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L. [Instituto Nacional de Astrofisica, Optica y Electronica, Apartado Postal 51-216, 72000 Puebla (Mexico); Ilic, D.; Kovacevic, A. [Isaac Newton Institute of Chile, Yugoslavia Branch, Belgrade (Serbia); Kollatschny, W. [Institut fuer Astrophysik, Georg-August-Universitaet, Goettingen (Germany); Bochkarev, N. G. [Sternberg Astronomical Institute, Moscow (Russian Federation); Leon-Tavares, J. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FIN-02540 Kylmaelae (Finland); Mercado, A. [Universidad Politecnica de Baja California, Av. de la Industria 291, 21010 Mexicali, B.C. (Mexico); Benitez, E.; Dultzin, D. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-264, Mexico, D.F. 04510 (Mexico); De la Fuente, E., E-mail: ashap@sao.ru [Instituto de Astronomia y Meteorologia, Dpto. de Fisica CUCEI, Universidad de Guadalajara, Av. Vallarta 2602, 44130 Guadalajara, Jalisco (Mexico)

    2012-09-15

    We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted H{alpha}, H{beta}, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the H{beta} and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F{sub max}/F{sub min}) of Ark 564 is between 1.5 for H{alpha} and 1.8 for the Fe II lines. The correlation between the Fe II and H{beta} flux variations is of higher significance than that of H{alpha} and H{beta} (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

  5. The variability of the Seyfert galaxy NGC 2992: the case for a revived AGN

    Science.gov (United States)

    Gilli, R.; Maiolino, R.; Marconi, A.; Risaliti, G.; Dadina, M.; Weaver, K. A.; Colbert, E. J. M.

    2000-03-01

    We report the transition to an active state of the nucleus in the Seyfert 1.9 galaxy NGC 2992, discovered by means of new hard X-ray data. While the 2-10 keV flux declined by a factor of ~ 20 from 1978 to 1994, two recent BeppoSAX observations in 1997 and in 1998 caught the nuclear emission raising back to the same level of activity observed in 1978. In both BeppoSAX observations the X-ray spectrum of the source is well represented by a power law with spectral index Gamma =~ 1.7, absorbed by a column density of N_H =~ 1022 cm-2 and characterized by a prominent iron Kalpha line. While in the second BeppoSAX data set the line properties appear to be consistent with those expected from accretion disc models, in the first BeppoSAX data set the iron feature is rather peculiar. The broadening is not significant and the line energy is E_Kalpha =6.62+/-0.07 keV, indicating emission from highly ionized iron. The line has too high equivalent width ( ~ 700 eV) to be produced by a hot scattering medium. By comparing these data with data previously in the literature, we interpret the spectral and flux changes in terms of different phases of rebuilding an accretion disc. The timescale for the disc rebuilding is estimated to range between 1 and 5 years. The X-ray data are complemented with optical and near-infrared followup spectra taken 1.5 months after the discovery of the X-ray burst. The spectra are characterized by prominent broad emission lines. There is also evidence for hot dust emission in the H and K bands that, however, is probably still in the process of increasing.

  6. Optical observations of the nearby galaxy IC342 with narrow band [SII] and Hα filters. I

    Directory of Open Access Journals (Sweden)

    Vučetić M.M.

    2013-01-01

    Full Text Available We present observations of a portion of the nearby spiral galaxy IC342 using narrow band [SII] and Hα filters. These observations were carried out in November 2011 with the 2m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, Hα and [SII] fluxes for 203 HII regions detected in two fields of view in IC342 galaxy. The number of detected HII regions is 5 times higher than previously known in these two parts of the galaxy. [Projekat Ministarstva nauke Republike Srbije, br. 176005: Emission nebulae: structure and evolution

  7. The Far-Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

    Science.gov (United States)

    Spinoglio, Luigi; Smith, Howard A.; Gonzalez-Alfonso, Eduardo; Fisher, Jacqueline

    2005-01-01

    We report on the analysis of the first complete far-infrared spectrum (43-197 microns) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO). In addition to the 7 expected ionic fine structure emission lines, the OH rotational lines at 79, 119 and 163 microns were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 micron line, where detected, is always in absorption. The observed line intensities were modelled together with IS0 Short Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the AGN component and the starburst component in the circumnuclear ring of approximately 3kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a big blue bump is ruled out. Based on the instantaneous starburst age of 5 Myr constrained by the Br gamma equivalent width in the starburst ring, and starburst synthesis models of the mid- and far-infrared fine-structure line emission, a low ionization parameter (U=10(exp -3.5)) and low densities (n=100 cm (exp -3)) are derived. Combining the AGN and starburst components, we succeed in modeling the overall UV to far-IR atomic spectrum of SGC 1068, reproducing the line fluxes to within a factor 2.0 on average with a standard deviation of 1.4. The OH 119 micron emission indicates that the line is collisionally excited, and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, non-local, non-LTE radiative transfer models. The models indicate that the bulk of the emission arises from the nuclear region, although some extended contribution from the starburst is not ruled out. The OH abundance

  8. TORUS AND ACTIVE GALACTIC NUCLEUS PROPERTIES OF NEARBY SEYFERT GALAXIES: RESULTS FROM FITTING INFRARED SPECTRAL ENERGY DISTRIBUTIONS AND SPECTROSCOPY

    International Nuclear Information System (INIS)

    Alonso-Herrero, Almudena; Ramos Almeida, Cristina; Mason, Rachel; Asensio Ramos, Andres; Rodriguez Espinosa, Jose Miguel; Perez-Garcia, Ana M.; Roche, Patrick F.; Levenson, Nancy A.; Elitzur, Moshe; Packham, Christopher; Young, Stuart; Diaz-Santos, Tanio

    2011-01-01

    We used the CLUMPY torus models and a Bayesian approach to fit the infrared spectral energy distributions and ground-based high angular resolution mid-infrared spectroscopy of 13 nearby Seyfert galaxies. This allowed us to put tight constraints on torus model parameters such as the viewing angle i, the radial thickness of the torus Y, the angular size of the cloud distribution σ torus , and the average number of clouds along radial equatorial rays N 0 . We found that the viewing angle i is not the only parameter controlling the classification of a galaxy into type 1 or type 2. In principle, type 2s could be viewed at any viewing angle i as long as there is one cloud along the line of sight. A more relevant quantity for clumpy media is the probability for an active galactic nucleus (AGN) photon to escape unabsorbed. In our sample, type 1s have relatively high escape probabilities, P esc ∼ 12%-44%, while type 2s, as expected, tend to have very low escape probabilities. Our fits also confirmed that the tori of Seyfert galaxies are compact with torus model radii in the range 1-6 pc. The scaling of the models to the data also provided the AGN bolometric luminosities L bol (AGN), which were found to be in good agreement with estimates from the literature. When we combined our sample of Seyfert galaxies with a sample of PG quasars from the literature to span a range of L bol (AGN) ∼ 10 43 -10 47 erg s -1 , we found plausible evidence of the receding torus. That is, there is a tendency for the torus geometrical covering factor to be lower (f 2 ∼ 0.1-0.3) at high AGN luminosities than at low AGN luminosities (f 2 ∼ 0.9-1 at ∼10 43 -10 44 erg s -1 ). This is because at low AGN luminosities the tori appear to have wider angular sizes (larger σ torus ) and more clouds along radial equatorial rays. We cannot, however, rule out the possibility that this is due to contamination by extended dust structures not associated with the dusty torus at low AGN luminosities

  9. The broad component of hydrogen emission lines in nuclei of Seyfert galaxies: Comments on a charge exchange model

    International Nuclear Information System (INIS)

    Katz, A.

    1975-01-01

    A model to account for the broad hydrogen line emission from the nuclei of Seyfert galaxies based on charge exchange and collisional processes, as proposed by Ptak and Stoner, is investigated. The model consists of a source of fast (E approx. 10 5 eV) protons streaming through a medium of quiescent gas. One of the major problems that results from such a model concerns the strong narrow hydrogen line core that would be produced, in direct conflict with the observations. The lines cannot arise from gas arranged throughout a spherical volume surrounding the source of the fast particles because the fast protons would produce far more ionizations than the possible number of recombinations. A very dense shell source of less than 1 AU in thickness and at least several tens of parsecs in radius must be invoked to reproduce the asymmetric broad profiles observed. There must be absorption throughout the center of the shell to account for the line profiles. The gas cannot be arranged in dense clumps throughout a large volume because momentum exchange of the gas with the primary particles would quickly accelerate any clumps. The energy balance and energy requirements of such a model are investigated, and it is found that an energy equal to or greater than the total luminosity of most Seyfert galaxies is required to produce the hydrogen line alone. The gas must be mostly neutral and den []e (N approx. 10 7 ) if a reasonable temperature is to be maintained

  10. Intra-night optical variability properties of X-ray bright Narrow-line Seyfert 1 galaxies

    Science.gov (United States)

    Ojha, Vineet; Chand, Hum; Gopal-Krishna

    2018-04-01

    We present Intra Night Optical Variability (INOV) study of the 9 Narrow-line Seyfert 1 (NLSy 1) galaxies which are detected in X-ray at more than 3σ level. Our observations cover a total of 9 nights ( 36 hr) with each NLSy 1 monitored for ≥ 3.5 hr in each night. After applying F-test to assess variability status of these sources, we found none of these sources to be variable. Such non-variability nature of X-ray detected NLSy 1 galaxies suggests the lack of jet dominance as far as X-ray emission is concerned. Higher photometric accuracy for these faint sources, achievable with the newly installed ARIES 3.6m DOT will be helpful.

  11. A Multiwavelength Study of POX 52, a Dwarf Seyfert Galaxy with an Intermediate-Mass Black Hole

    Science.gov (United States)

    Barth, Aaron

    2004-07-01

    We propose a comprehensive optical, UV, and X-ray investigation of the unique galaxy POX 52. POX 52 is a Seyfert 1 galaxy with unprecedented properties: its host galaxy appears to be a dwarf elliptical, and its stellar velocity dispersion is only 36 km/s. The stellar velocity dispersion and the broad emission-line widths both suggest a black hole mass of order 10^5 solar masses, placing POX 52 in a region of AGN parameter space that is almost completely unexplored at present. We request ACS/HRC imaging to perform a definitive measurement of the host galaxy structure; STIS UV and optical spectroscopy to study the nonstellar continuum and the structure of the broad-line region; and Chandra ACS imaging to detect the X-ray emission from the nucleus and investigate its spectral and variability properties. The results of this program will give a detailed understanding of the host galaxy and accretion properties of one of the very few known black holes in the mass range around 10^5 solar masses.

  12. Space Telescope and Optical Reverberation Mapping Project.I. Ultraviolet Observations of the Seyfert 1 Galaxy NGC 5548 with the Cosmic Origins Spectrograph on Hubble Space Telescope

    NARCIS (Netherlands)

    De Rosa, G.; Peterson, B.M.; Ely, J.; Kriss, G.A.; Crenshaw, D.M.; Horne, K.; Korista, K.T.; Netzer, H.; Pogge, R.W.; Arévalo, P.; Barth, A.J.; Bentz, M.C.; Brandt, W.N.; Breeveld, A.A.; Brewer, B.J.; Dalla Bontà, E.; De Lorenzo-Cáceres, A.; Denney, K.D.; Dietrich, M.; Edelson, R.; Evans, P.A.; Fausnaugh, M.M.; Gehrels, N.; Gelbord, J.M.; Goad, M.R.; Grier, C.J.; Grupe, D.; Hall, P.B.; Kaastra, J.; Kelly, B.C.; Kennea, J.A.; Kochanek, C.S.; Lira, P.; Mathur, S.; McHardy, I.M.; Nousek, J.A.; Pancoast, A.; Papadakis, I.; Pei, L.; Schimoia, J.S.; Siegel, M.; Starkey, D.; Treu, T.; Uttley, P.; Vaughan, S.; Vestergaard, M.; Villforth, C.; Yan, H.; Young, S.; Zu, Y.

    2015-01-01

    We describe the first results from a six-month long reverberation-mapping experiment in the ultraviolet based on 171 observations of the Seyfert 1 galaxy NGC 5548 with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Significant correlated variability is found in the continuum and

  13. A search for extragalactic pulsars in the local group galaxies IC 10 and Barnard’s galaxy

    International Nuclear Information System (INIS)

    Al Noori, H; Roberts, M S E; Champion, D; McLaughlin, M; Ransom, Scott; Ray, P S

    2017-01-01

    As of today, more than 2500 pulsars have been found, nearly all in the Milky Way, with the exception of ∼28 pulsars in the Small and Large Magellanic Clouds. However, there have been few published attempts to search for pulsars deeper in our Galactic neighborhood. Two of the more promising Local Group galaxies are IC 10 and NGC 6822 (also known as Barnard’s Galaxy) due to their relatively high star formation rate and their proximity to our galaxy. IC 10 in particular, holds promise as it is the closest starburst galaxy to us and harbors an unusually high number of Wolf-Rayet stars, implying the presence of many neutron stars. We observed IC 10 and NGC 6822 at 820 MHz with the Green Bank Telescope for ∼15 and 5 hours respectively, and put a strong upper limit of 0.1 mJy on pulsars in either of the two galaxies. We also performed single pulse searches of both galaxies with no firm detections. (paper)

  14. JET PROPERTIES OF GeV-SELECTED RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES AND POSSIBLE CONNECTION TO THEIR DISK AND CORONA

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiao-Na; Lin, Da-Bin; Liang, En-Wei [Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Zhang, Jin [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Xue, Zi-Wei; Zhang, Shuang-Nan, E-mail: zhang.jin@hotmail.com [Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011 (China)

    2015-01-01

    The observed spectral energy distributions of five GeV-selected narrow-line Seyfert 1 (NLS1) galaxies are fitted with a model including the radiation ingredients from the relativistic jet, the accretion disk, and the corona. We compare the properties of these GeV NLS1 galaxies with flat spectrum radio quasars (FSRQs), BL Lacertae objects (BL Lacs), and radio-quiet (RQ) Seyfert galaxies, and explore possible hints for jet-disk/corona connection. Our results show that the radiation physics and the jet properties of the GeV NLS1 galaxies resemble that of FSRQs. The luminosity variations of PMN J0948+0022 and 1H 0323+342 at the GeV band is tightly correlated with the beaming factor (δ), similar to that observed in FSRQ 3C 279. The accretion disk luminosities and the jet powers of the GeV NLS1 galaxies cover both the ranges of FSRQs and BL Lacs. With the detection of bright corona emission in 1H 0323+342, we show that the ratio of the corona luminosity (L {sub corona}) to the accretion disk luminosity (L {sub d}) is marginally within the high end of this ratio distribution for an RQ Seyfert galaxy sample, and the variation of jet luminosity may connect with L {sub corona}. However, it is still unclear whether a system with a high L {sub corona}/L {sub d} ratio prefers to power a jet.

  15. An Expanded Rossi X-Ray Timing Explorer Survey of X-Ray Variability in Seyfert 1 Galaxies

    Science.gov (United States)

    Markowitz, A.; Edelson, R.

    2004-12-01

    The first seven years of RXTE monitoring of Seyfert 1 active galactic nuclei have been systematically analyzed to yield five homogeneous samples of 2-12 keV light curves, probing hard X-ray variability on successively longer durations from ~1 day to ~3.5 yr. The 2-10 keV variability on timescales of ~1 day, as probed by ASCA, is included. All sources exhibit stronger X-ray variability toward longer timescales, but the increase is greater for relatively higher luminosity sources. Variability amplitudes are anticorrelated with X-ray luminosity and black hole mass, but amplitudes saturate and become independent of luminosity or black hole mass toward the longest timescales. The data are consistent with the models of power spectral density (PSD) movement described by Markowitz and coworkers and McHardy and coworkers, whereby Seyfert 1 galaxies' variability can be described by a single, universal PSD shape whose break frequency scales with black hole mass. The best-fitting scaling relations between variability timescale, black hole mass, and X-ray luminosity imply an average accretion rate of ~5% of the Eddington limit for the sample. Nearly all sources exhibit stronger variability in the relatively soft 2-4 keV band compared to the 7-12 keV band on all timescales. There are indications that relatively less luminous or less massive sources exhibit a greater degree of spectral variability for a given increase in overall flux.

  16. Near-infrared mapping of ARP 299 (IC 694-NGC 3690) - colliding galaxies unveiled

    International Nuclear Information System (INIS)

    Telesco, C.M.; Decher, R.; Gatley, I.; Edinburgh Royal Observatory, England)

    1985-01-01

    Near-infrared maps and multicolor photometry of the interacting galaxies IC 694 and NGC 3690 which form Arp 299 (= Markarian 171) are presented. These data reveal for the first time the distribution of nuclei and old red stars in a cataclysmically interacting system. The nuclei are considerably offset from the visual centroids of the galaxies but not from the mass centroids. The near-infrared colors of the most active regions are strongly affected by extinction, emission form hot dust, and bremsstrahlung. Near-infrared emission is also identified with secondary regions of star formation, probably resulting from the galaxies interaction. 24 references

  17. Observation of soft X-ray spectra from a Seyfert 1 and a narrow emission-line galaxy

    International Nuclear Information System (INIS)

    Singh, K.P.; Garmire, G.P.; Nousek, J.

    1985-01-01

    The 0.2-40 keV X-ray spectra of the Seyfert 1 galaxy Mrk 509 and the narrow emission-line galaxy NGC 2992 are analyzed. The results suggest the presence of a steep soft X-ray component in Mrk 509 in addition to the well-known Gamma = 1.7 component found in other active galactic nuclei in the 2-40 keV energy range. The soft X-ray component is interpreted as due to thermal emission from a hot gas, probably associated with the highly ionized gas observed to be outflowing from the galaxy. The X-ray spectrum of NGC 2992 does not show any steepening in the soft X-ray band and is consistent with a single power law (Gamma = 1.78) with very low absorbing column density of 4 x 10 to the 21st/sq cm. A model with partial covering of the nuclear X-ray source is preferred, however, to a simple model with a single power law and absorption. 34 references

  18. EVIDENCE FOR AN INTERACTION IN THE NEAREST STARBURSTING DWARF IRREGULAR GALAXY IC 10

    International Nuclear Information System (INIS)

    Nidever, David L.; Slater, Colin T.; Bell, Eric F.; Ashley, Trisha; Simpson, Caroline E.; Ott, Jürgen; Johnson, Megan; Stanimirović, Snežana; Putman, Mary; Majewski, Steven R.; Jütte, Eva; Oosterloo, Tom A.; Burton, W. Butler

    2013-01-01

    Using deep 21 cm H I data from the Green Bank Telescope we have detected an ≳18.3 kpc long gaseous extension associated with the starbursting dwarf galaxy IC 10. The newly found feature stretches 1.°3 to the northwest and has a large radial velocity gradient reaching to ∼65 km s –1 lower than the IC 10 systemic velocity. A region of higher column density at the end of the extension that possesses a coherent velocity gradient (∼10 km s –1 across ∼26') transverse to the extension suggests rotation and may be a satellite galaxy of IC 10. The H I mass of IC 10 is 9.5 × 10 7 (d/805 kpc) 2 M ☉ and the mass of the new extension is 7.1 × 10 5 (d/805 kpc) 2 M ☉ . An IC 10-M31 orbit using known radial velocity and proper motion values for IC 10 show that the H I extension is inconsistent with the trailing portion of the orbit so that an M31-tidal or ram pressure origin seems unlikely. We argue that the most plausible explanation for the new feature is that it is the result of a recent interaction (and possible late merger) with another dwarf galaxy. This interaction could not only have triggered the origin of the recent starburst in IC 10, but could also explain the existence of previously found counter-rotating H I gas in the periphery of the IC 10 which was interpreted as originating from primordial gas infall

  19. Mapping the gas-to-dust ratio in the edge-on spiral galaxy IC2531

    Science.gov (United States)

    Baes, Maarten; Gentile, Gianfranco; Allaert, Flor; Kuno, Nario; Verstappen, Joris

    2012-04-01

    The gas-to-dust ratio is an important diagnostic of the chemical evolution of galaxies, but unfortunately, there are only a few unbiased studies of the gas-to-dust ratio within galaxies and among different galaxies. We want to take advantage of the revolutionary capabilities of the Herschel Space Observatory and the special geometry of edge-on spiral galaxies to derive accurate gas and dust mass profiles in the edge-on spiral galaxy IC2531, the only southern galaxy from a sample of large edge-on spirals observed with Herschel. We already have a wealth of ancillary data and detailed radiative transfer modelling at our disposal for this galaxy, and now request CO observations to map the molecular gas distribution. With our combined dataset, we will investigate the radial behaviour of the gas-to-dust ratio, compare it with the properties of the stellar population and the dark matter distribution, and test the possibility to use the far-infrared emission from dust to determine the total ISM mass in galaxies.

  20. DISCOVERY OF TWO SUPERNOVAE IN THE NUCLEAR REGIONS OF THE LUMINOUS INFRARED GALAXY IC 883

    Energy Technology Data Exchange (ETDEWEB)

    Kankare, E.; Mattila, S.; Takalo, A. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Vaeisaelaentie 20, FI-21500 Piikkioe (Finland); Ryder, S. [Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710 (Australia); Vaeisaenen, P. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935 (South Africa); Alberdi, A.; Perez-Torres, M.-A.; Romero-Canizales, C. [Instituto de Astrofsica de Andalucia, IAA-CSIC, Apartado 3004, 18080 Granada (Spain); Alonso-Herrero, A.; Colina, L. [Departamento de Astrofisica, Centro de Astrobiologia, CSIC/INTA, Carretera de Torrejon a Ajalvir, km 4, 28850, Torrejon de Ardoz, Madrid (Spain); Efstathiou, A. [School of Sciences, European University Cyprus, Diogenes Street, Engomi, 1516 Nicosia (Cyprus); Kotilainen, J. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Vaeisaelaentie 20, FI-21500 Piikkioe (Finland); Melinder, J., E-mail: erkki.kankare@utu.fi [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, 106 91 Stockholm (Sweden)

    2012-01-10

    We report the discovery of two consecutive supernovae (SNe), 2010cu and 2011hi, located at 0.''37 (180 pc) and 0.''79 (380 pc) projected distance, respectively, from the center of the K-band nucleus of the luminous infrared galaxy (LIRG) IC 883. The SNe were discovered in an ongoing near-infrared K-band search for core-collapse SNe in such galaxies using the ALTAIR/NIRI adaptive optics system with laser guide star at the Gemini-North Telescope. These are thus the closest SNe yet discovered to an LIRG nucleus in optical or near-infrared wavelengths. The near-infrared light curves and colors of both SNe are consistent with core-collapse events. Both SNe seem to suffer from relatively low host galaxy extinction suggesting that regardless of their low projected galactocentric distances, they are not deeply buried in the nuclear regions of the host galaxy.

  1. THE X-RAY POWER SPECTRAL DENSITY FUNCTION AND BLACK HOLE MASS ESTIMATE FOR THE SEYFERT ACTIVE GALACTIC NUCLEUS IC 4329a

    International Nuclear Information System (INIS)

    Markowitz, A.

    2009-01-01

    We present the X-ray broadband power spectral density function (PSD) of the X-ray-luminous Seyfert IC 4329a, constructed from light curves obtained via Rossi X-ray Timing Explorer monitoring and an XMM-Newton observation. Modeling the 3-10 keV PSD using a broken power-law PSD shape, a break in power-law slope is significantly detected at a temporal frequency of 2.5 +2.5 -1.7 x 10 -6 Hz, which corresponds to a PSD break timescale T b of 4.6 +10.1 -2.3 days. Using the relation between T b , black hole mass M BH , and bolometric luminosity as quantified by McHardy and coworkers, we infer a black hole mass estimate of M BH = 1.3 +1.0 -0.3 x 10 8 M sun and an accretion rate relative to Eddington of 0.21 +0.06 -0.10 for this source. Our estimate of M BH is consistent with other estimates, including that derived by the relation between M BH and stellar velocity dispersion. We also present PSDs for the 10-20 and 20-40 keV bands; they lack sufficient temporal frequency coverage to reveal a significant break, but are consistent with the same PSD shape and break frequency as in the 3-10 keV band.

  2. SDSS J211852.96-073227.5: a new γ-ray flaring narrow-line Seyfert 1 galaxy

    Science.gov (United States)

    Yang, Hui; Yuan, Weimin; Yao, Su; Li, Ye; Zhang, Jin; Zhou, Hongyan; Komossa, S.; Liu, He-Yang; Jin, Chichuan

    2018-04-01

    We report on the identification of a new γ-ray-emitting narrow-line Seyfert 1 (NLS1) galaxy, SDSS J211852.96-073227.5 (hereafter J2118-0732). The galaxy, at a redshift of 0.26, is associated with a radio source of flat/inverted spectrum at high radio frequencies. The analysis of its optical spectrum obtained in the Sloan Digital Sky Survey revealed a small linewidth of the broad component of the Hβ line (FWHM = 1585 km s-1), making it a radio-loud NLS1 galaxy - an intriguing class of active galactic nuclei with exceptional multi-wavelength properties. A new γ-ray source centred at J2118-0732 was sporadically detected during 2009-2013 in form of flares by the Fermi-LAT. Our XMM-Newton observations revealed a flat X-ray spectrum described by a simple power law, and a flux variation by a factor of ˜2.5 in 5 months. The source also shows intraday variability in the infrared band. Its broad-band spectral energy distribution can be modelled by emission from a simple one-zone leptonic jet model, and the flux drop from infrared to X-rays in five months can be explained by changes of the jet parameters, though the exact values may be subject to relatively large uncertainties. With the NLS1-blazar composite nucleus, the clear detection of the host galaxy and the synchronous variations in the multi-wavelength fluxes, J2118-0732 provides a new perspective on the formation and evolution of relativistic jets under the regime of relatively small black hole masses and high accretion rates.

  3. Gemini Near Infrared Field Spectrograph Observations of the Seyfert 2 Galaxy MRK 573: In Situ Acceleration of Ionized and Molecular Gas Off Fueling Flows

    Science.gov (United States)

    Fischer, Travis C.; Machuca, C.; Diniz, M. R.; Crenshaw, D. M.; Kraemer, S. B.; Riffel, R. A.; Schmitt, H. R.; Baron, F.; Storchi-Bergmann, T.; Straughn, A. N.; hide

    2016-01-01

    We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in approximately 700 x 2100 pc(exp 2) circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out to several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges.

  4. The extreme behavior of the radio-loud narrow-line Seyfert 1 galaxy J0849+5108

    Energy Technology Data Exchange (ETDEWEB)

    Maune, Jeremy D.; Eggen, Joseph R.; Miller, H. Richard [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303-3083 (United States); Marshall, Kevin [Department of Physics and Astronomy, Widener University, Chester, PA 19013 (United States); Readhead, Anthony C. S.; Hovatta, Talvikki; King, Oliver, E-mail: maune@chara.gsu.edu [Cahill Laboratory of Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-10-10

    Simultaneous radio, optical (both photometry and polarimetry), X-ray, and γ-ray observations of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy J0849+5108 are presented. A massive three-magnitude optical flare across five nights in 2013 April is detected, along with associated flux increases in the γ-ray, infrared, and radio regimes; no comparable event was detected in the X-rays, though this may be due to poor coverage. A spectral energy distribution (SED) for the object using quasi-simultaneous data centered on the optical flare is compared to the previously published SEDs for the object by D'Ammando et al. The flare event coincided with a high degree of optical polarization. High amplitude optical microvariability is clearly detected, and is found to be of comparable amplitude when the object is observed in both faint and bright states. The object is also seen to undergo rapid shifts in polarization in both degree and electric vector position angle within a single night. J0849+5108 appears to show even more extreme variability than that previously reported for the similar object J0948+0022. These observations appear to support the growing claim that some RL-NLSy1 galaxies constitute a sub-class of blazar-like active galactic nuclei.

  5. The extreme behavior of the radio-loud narrow-line Seyfert 1 galaxy J0849+5108

    International Nuclear Information System (INIS)

    Maune, Jeremy D.; Eggen, Joseph R.; Miller, H. Richard; Marshall, Kevin; Readhead, Anthony C. S.; Hovatta, Talvikki; King, Oliver

    2014-01-01

    Simultaneous radio, optical (both photometry and polarimetry), X-ray, and γ-ray observations of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy J0849+5108 are presented. A massive three-magnitude optical flare across five nights in 2013 April is detected, along with associated flux increases in the γ-ray, infrared, and radio regimes; no comparable event was detected in the X-rays, though this may be due to poor coverage. A spectral energy distribution (SED) for the object using quasi-simultaneous data centered on the optical flare is compared to the previously published SEDs for the object by D'Ammando et al. The flare event coincided with a high degree of optical polarization. High amplitude optical microvariability is clearly detected, and is found to be of comparable amplitude when the object is observed in both faint and bright states. The object is also seen to undergo rapid shifts in polarization in both degree and electric vector position angle within a single night. J0849+5108 appears to show even more extreme variability than that previously reported for the similar object J0948+0022. These observations appear to support the growing claim that some RL-NLSy1 galaxies constitute a sub-class of blazar-like active galactic nuclei.

  6. Contribution of parsec-scale material onto the polarized X-ray spectrum of type-1 Seyfert galaxies

    Science.gov (United States)

    Marin, F.; Dovčiak, M.; Kammoun, E. S.

    2018-04-01

    Type-1 radio-quiet active galactic nuclei (AGN) are seen from the polar direction and offer a direct view of their central X-ray engine. If most of X-ray photons have traveled from the primary source to the observer with minimum light-matter interaction, a fraction of radiation is emitted at different directions and is reprocessed by the parsec-scale equatorial circumnuclear region or the polar outflows. It is still unclear how much the polarization expected from type-1 AGN is affected by radiation that have scattered on the distant AGN components. In this paper, we examine the contribution of remote material onto the polarized X-ray spectrum of type-1 Seyfert galaxies using radiative transfer Monte Carlo codes. We find that the observed X-ray polarization strongly depends on the initial polarization emerging from the disk-corona system. For unpolarized and parallelly polarized photons (parallel to the disk), the contribution is negligible below 3 keV and tends to increase the polarization degree by up to one percentage points at higher energies, smoothing out the energy-dependent variations of the polarization angle. For perpendicularly polarized corona photons, the addition of the circumnuclear scattered (parallel) component adds to the polarization above 10keV, decreases polarization below 10 keV and shifts the expected 90° rotation of the polarization angle to lower energies. In conclusion, we found that simulations of Seyfert-1s that do not account for reprocessing on the parsec-scale equatorial and polar material are under- or over-estimating the X-ray polarization by 0.1 - 1 percentage points.

  7. PROBING THE PHYSICS OF NARROW LINE REGIONS IN ACTIVE GALAXIES. II. THE SIDING SPRING SOUTHERN SEYFERT SPECTROSCOPIC SNAPSHOT SURVEY (S7)

    Energy Technology Data Exchange (ETDEWEB)

    Dopita, Michael A.; Davies, Rebecca; Kewley, Lisa; Hampton, Elise; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Kharb, Preeti; Jose, Jessy; Bhatt, Harish; Ramya, S. [Indian Institute of Astrophysics, Koramangala 2 B Block, Bangalore 560034 (India); Scharwächter, Julia [LERMA, Observatoire de Paris, CNRS, UMR 8112, 61 Avenue de l’Observatoire, F-75014 Paris (France); Jin, Chichuan [Qian Xuesen Laboratory for Space Technology, Beijing (China); Banfield, Julie [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW, 1710 Australia (Australia); Zaw, Ingyin [New York University (Abu Dhabi), 70 Washington Square South, New York, NY 10012 (United States); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); James, Bethan [Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA (United Kingdom); Srivastava, Shweta, E-mail: Michael.Dopita@anu.edu.au [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009 (India)

    2015-03-15

    Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph mounted on the ANU 2.3 m telescope located at the Siding Spring Observatory to deliver an integral field of 38 × 25 arcsec at a spectral resolution of R = 7000 in the red (530–710 nm), and R = 3000 in the blue (340–560 nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the Hβ and [O iii] λ5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the Hβ and [O iii] λ5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in [O iii] λ5007, [N ii] λ6584, and Hα, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding H ii regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines.

  8. ALMA HCN AND HCO{sup +} J  = 3 − 2 OBSERVATIONS OF OPTICAL SEYFERT AND LUMINOUS INFRARED GALAXIES: CONFIRMATION OF ELEVATED HCN-TO-HCO{sup +} FLUX RATIOS IN AGNS

    Energy Technology Data Exchange (ETDEWEB)

    Imanishi, Masatoshi; Nakanishi, Kouichiro [National Astronomical Observatory of Japan, National Institutes of Natural Sciences (NINS), 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Izumi, Takuma, E-mail: masa.imanishi@nao.ac.jp [Institute of Astronomy, School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)

    2016-12-01

    We present the results of our ALMA observations of three active galactic nucleus (AGN)-dominated nuclei in optical Seyfert 1 galaxies (NGC 7469, I Zw 1, and IC 4329 A) and eleven luminous infrared galaxies (LIRGs) with various levels of infrared estimated energetic contributions by AGNs at the HCN and HCO{sup +} J  = 3 − 2 emission lines. The HCN and HCO{sup +} J  = 3 − 2 emission lines are clearly detected at the main nuclei of all sources, except for IC 4329 A. The vibrationally excited ( v {sub 2} = 1f) HCN J  = 3 − 2 and HCO{sup +} J  = 3 − 2 emission lines are simultaneously covered, and HCN v {sub 2} = 1f J  = 3 − 2 emission line signatures are seen in the main nuclei of two LIRGs, IRAS 12112+0305 and IRAS 22491–1808, neither of which shows clear buried AGN signatures in the infrared. If the vibrational excitation is dominated by infrared radiative pumping, through the absorption of infrared 14 μ m photons, primarily originating from AGN-heated hot dust emission, then these two LIRGs may contain infrared-elusive, but (sub)millimeter-detectable, extremely deeply buried AGNs. These vibrationally excited emission lines are not detected in the three AGN-dominated optical Seyfert 1 nuclei. However, the observed HCN v {sub 2} = 1f to v  = 0 flux ratios in these optical Seyferts are still consistent with the intrinsic flux ratios in LIRGs with detectable HCN v {sub 2} = 1f emission lines. The observed HCN-to-HCO{sup +} J  = 3 − 2 flux ratios tend to be higher in galactic nuclei with luminous AGN signatures compared with starburst-dominated regions, as previously seen at J  = 1 − 0 and J  = 4 − 3.

  9. Unification of X-ray Winds in Seyfert Galaxies: From Ultra-fast Outflows to Warm Absorbers

    Science.gov (United States)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Nemmen, R. S.; Braito, V.; Gaspari, M.; Reynolds, C. S.

    2013-01-01

    The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60 per cent, consistent with previous studies. The fraction of sources with UFOs is >34 per cent, >67 per cent of which also show WAs. The large dynamic range obtained when considering all the absorbers together, spanning several orders of magnitude in ionization, column, velocity and distance allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. In all the cases, the absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. These evidence strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The UFOs are likely launched from the inner accretion disc and the WAs at larger distances, such as the outer disc and/or torus. We argue that the observed parameters and correlations are, to date, consistent with both radiation pressure through Compton scattering and magnetohydrodynamic processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, show

  10. Probing the physics of Seyfert galaxies using their emission-line regions

    Energy Technology Data Exchange (ETDEWEB)

    Shastri, P., E-mail: prajval.shastri@gmail.com; Kharb, P.; Jose, J.; Ramya, S.; Bhatt, H. C.; Gupta, M. [Indian Institute of Astrophysics, Bangalore (India); Dopita, M.; Kewley, L.; Davies, R.; Sutherland, R.; Hampton, E. [RSAA, Australian National University, Canberra (Australia); Scharwächter, J. [LERMA, Paris Observatory (France); Banfield, J. [CSIRO Astronomy and Space Science, Epping (Australia); Srivastava, S. [Department of Physics, DDU Gorakhpur University, Gorakhpur (India); Jin, J. [Department of Physics, University of Durham (United Kingdom); Basurah, H. [Astronomy Department, King Abdulaziz University, Jeddah (Saudi Arabia); Fischer, S. [German Aerospace Center, Bonn (Germany); Panda, S. [National Institute of Technology, Rourkela (India); Indian Institute of Astrophysics, Bangalore (India); Sundar, M. N. [Jain University, Bangalore (India); Radhakrishnan, V. [Broadcom Corporation, Bangalore (India)

    2015-12-31

    Active galaxies have powerhouses of radiation in their nuclear regions that are driven by accreting super-massive black holes. The accretion system also generates outflows of ionized gas and synchrotron-emitting bipolar jets of plasma, which could have a significant impact on the host galaxy. We have initiated an investigation into the physics of nearby active galaxies by studying the morphology, kinematics, excitation abundance structure, and radio structure of about 120 nearby targets. We present a few early results from this investigation.

  11. Reddening and He i{sup ∗} λ 10830 Absorption Lines in Three Narrow-line Seyfert 1 Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shaohua; Zhou, Hongyan; Shi, Xiheng; Pan, Xiang; Ji, Tuo; Jiang, Peng; Wang, Shufen [Polar Research Institute of China, 451 Jinqiao Road, Shanghai, 200136 (China); Liu, Wenjuan [Key Laboratory for the Structure and Evolution of Celestial Objects, Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Jiang, Ning, E-mail: zhangshaohua@pric.org.cn, E-mail: zhouhongyan@pric.org.cn [Key Laboratory for Researches in Galaxies and Cosmology, Department of Astronomy, University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui, 230026 (China)

    2017-08-20

    We report the detection of heavy reddening and the He i* λ 10830 absorption lines at the active galactic nucleus (AGN) redshift in three narrow-line Seyfert 1 galaxies: SDSS J091848.61+211717.0, SDSS J111354.66+124439.0, and SDSS J122749.13+321458.9. They exhibit very red optical to near-infrared colors, narrow Balmer/Paschen broad emission lines and He i* λ 10830 absorption lines. The ultraviolet-optical-infrared nucleus continua are reddened by the SMC extinction law of E ( B − V ) ∼ 0.74, 1.17, and 1.24 mag for three objects, which are highly consistent with the values obtained from the broad-line Balmer decrements, but larger than those of narrow emission lines. The reddening analysis suggests that the extinction dust simultaneously obscures the accretion disk, the broad emission-line region, and the hot dust from the inner edge of the torus. It is possible that the dust obscuring the AGN structures is the dusty torus itself. Furthermore, the Cloudy analysis of the He i* λ 10830 absorption lines proposes the distance of the absorption materials to be the extend scale of the torus, which greatly increases probabilities of the obscure and absorption materials being the dusty torus.

  12. The discovery of an O VII emission line in the ASCA spectrum of the Seyfert galaxy NGC 3783

    Science.gov (United States)

    George, I. M.; Turner, T. J.; Netzer, H.

    1995-01-01

    We report the first observation of an O VII 0.57 keV emission line in a Seyfert 1 galaxy. NGC 3783 was observed by ASCA twice over a period of 4 days in 1993 December. The source exhibited a approximately 30% change in intensity between the two observations, with most of the variability taking place as a result of steepening of the continuum less than or approximately equal to 1 keV. Spectra from both observations show intense absorption features in the 0.5-1.5 keV band, which can be well fitted by an ionized absorber model of solar composition, column density of 10(exp 22.2)/sq cm and ionization parameter of approximately 7-8; the strongest absorption features being due to O VII and O VIII. Two emission features are also seen in the spectra which we identify as O VII 0.57 keV (equivalent width approximately equals 36 eV) and O VIII 0.65 keV (equivalent width approximately equals 11 eV). We also show that the 3-6 keV continuum of the source is well fitted by a Gamma = 1.3-1.4 power-law continuum, a narrow neutral iron K-shell fluorescence line and a strong iron K-shell absorption edge, possibly corresponding to highly ionized iron.

  13. The changing source of X-ray reflection in the radio-intermediate Seyfert 1 galaxy III Zw 2

    Science.gov (United States)

    Gonzalez, A. G.; Waddell, S. G. H.; Gallo, L. C.

    2018-03-01

    We report on X-ray observations of the radio-intermediate, X-ray bright Seyfert 1 galaxy, III Zw 2, obtained with XMM-Newton, Suzaku, and Swift over the past 17 yr. The source brightness varies significantly over yearly time-scales, but more modestly over periods of days. Pointed observations with XMM-Newton in 2000 and Suzaku in 2011 show spectral differences despite comparable X-ray fluxes. The Suzaku spectra are consistent with a power-law continuum and a narrow Gaussian emission feature at ˜6.4 keV, whereas the earlier XMM-Newton spectrum requires a broader Gaussian profile and soft-excess below ˜2 keV. A potential interpretation is that the primary power-law emission, perhaps from a jet base, preferentially illuminates the inner accretion disc in 2000, but the distant torus in 2011. The interpretation could be consistent with the hypothesized precessing radio jet in III Zw 2 that may have originated from disc instabilities due to an ongoing merging event.

  14. NuSTAR spectral analysis of two bright Seyfert 1 galaxies: MCG +8-11-11 and NGC 6814

    Science.gov (United States)

    Tortosa, A.; Bianchi, S.; Marinucci, A.; Matt, G.; Middei, R.; Piconcelli, E.; Brenneman, L. W.; Cappi, M.; Dadina, M.; De Rosa, A.; Petrucci, P. O.; Ursini, F.; Walton, D. J.

    2018-01-01

    We report on the NuSTAR observations of two bright Seyfert 1 galaxies, namely MCG +8-11-11 (100 ks) and NGC 6814 (150 ks). The main goal of these observations was to investigate the Comptonization mechanisms acting in the innermost regions of an active galactic nucleus (AGN) which are believed to be responsible for the UV/X-ray emission. The spectroscopic analysis of the NuSTAR spectra of these two sources revealed that although they had different properties overall (black hole masses, luminosity and Eddington ratios), they had very similar coronal properties. Both presented a power-law spectrum with a high-energy cut-off at ∼150-200 keV, a relativistically broadened Fe K α line and the associated disc reflection component, plus a narrow iron line likely emitted in Compton thin and distant matter. The intrinsic continuum was well described by Comptonization models that show for MCG +8-11-11 a temperature of the coronal plasma of kTe ∼ 60 keV and an extrapolated optical depth τ = 1.8; for NGC 6814, the coronal temperature was kTe ∼ 45 keV with an extrapolated optical depth of τ = 2.5. We compare and discuss these values to some most common Comptonization models that aim at explaining the energy production and stability of coronae in AGNs.

  15. The radio structure of the peculiar narrow-line Seyfert 1 galaxy candidate J1100+4421

    Science.gov (United States)

    Gabányi, K. É.; Frey, S.; Paragi, Z.; Järvelä, E.; Morokuma, T.; An, T.; Tanaka, M.; Tar, I.

    2018-01-01

    Narrow-line Seyfert 1 galaxies (NLS1) are an intriguing subclass of active galactic nuclei. Their observed properties indicate low central black hole mass and high accretion rate. The extremely radio-loud NLS1 sources often show relativistic beaming and are usually regarded as younger counterparts of blazars. Recently, the object SDSS J110006.07+442144.3 was reported as a candidate NLS1 source. The characteristics of its dramatic optical flare indicated its jet-related origin. The spectral energy distribution of the object was similar to that of the γ-ray detected radio-loud NLS1, PMN J0948+0022. Our high-resolution European very long baseline interferometry network observations at 1.7 and 5 GHz revealed a compact core feature with a brightness temperature of ≳1010 K. Using the lowest brightness temperature value and assuming a moderate Lorentz factor of ∼9, the jet viewing angle is ≲26°. Archival Very Large Array data show a large-scale radio structure with a projected linear size of ∼150 kpc reminiscent of double-sided morphology.

  16. The Origin of the Extra-nuclear X-ray Emission in the Seyfert Galaxy NGC 2992

    Science.gov (United States)

    Colbert, E. J. M.; Strickland, D. K.; Veilleux, S.; Weaver, K. A.

    2004-12-01

    We present an analysis of a Chandra ACIS observation of the edge-on Seyfert galaxy NGC 2992. We find extended X-ray emission with Lx(total) in excess of 10**40 erg/s. The brightest nebula is positioned a few 100 pc from the X-ray core, and is spatially coincident with optical line and radio emission. This emission nebula may be energized by the AGN, as opposed to a nuclear starburst. The expected kpc-scale X-ray emission due to a starburst-driven wind is larger than a few 10**39 erg/s, and we present large-scale X-ray emission that may be associated with such an outflow. The extra-nuclear emission has a very soft spectrum. Chandra and XMM spectra of the total nuclear region show a very prominent ``soft excess'' below 2-3 keV. We shall discuss the spectral properties of this soft excess, and will compare with the results from the spatial analysis, and with AGN and starburst models for extranuclear X-ray nebulae.

  17. Detection of Faint BLR Components in the Starburst/Seyfert Galaxy NGC 6221 and Measure of the Central BH Mass

    Energy Technology Data Exchange (ETDEWEB)

    La Franca, Fabio [Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Roma (Italy); Onori, Francesca [Netherlands Institute for Space Research, SRON, Utrecht (Netherlands); Ricci, Federica; Bianchi, Stefano [Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Roma (Italy); Marconi, Alessandro [Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Sesto Fiorentino (Italy); Sani, Eleonora [European Southern Observatory, Santiago (Chile); Vignali, Cristian, E-mail: lafranca@fis.uniroma3.it [Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna (Italy)

    2016-04-18

    In the last decade, using single epoch virial based techniques in the optical band, it has been possible to measure the central black hole mass on large type 1 Active Galactic Nuclei (AGN) samples. However, these measurements use the width of the broad line region (BLR) as a proxy of the virial velocities and are therefore difficult to be carried out on those obscured (type 2) or low luminosity AGN where the nuclear component does not dominate in the optical. Here we present the optical and near infrared spectrum of the starburst/Seyfert galaxy NGC 6221, observed with X-shooter/VLT. Previous observations of NGC 6221 in the X-ray band shows an absorbed (N{sub H}=8.5±0.4×10{sup 21}cm{sup -2}) spectrum typical of a type 2 AGN with luminosity log(L{sub 14−195}/ergs{sup −1}) = 42.05, while in the optical band its spectrum is typical of a reddened (A{sub V} = 3) starburst. Our deep X-shooter/VLT observations have allowed us to detect faint broad emission in the Hα, HeI, and Paβ lines (FWHM ~1400–2300 km s{sup −1}) confirming previous studies indicating that NGC 6221 is a reddened starbust galaxy which hosts an AGN. We use the measure of the broad components to provide a first estimate of its central black hole mass (M{sub BH}=10{sup 6.6±0.3}M{sub ⊙}, λ{sub Edd} = 0.01−0.03), obtained using recently calibrated virial relations suitable for moderately obscured (N{sub H} < 10{sup 24} cm{sup −2}) AGN.

  18. Structure of the Circumnuclear Region of Seyfert 2 Galaxies Revealed by RXTE Hard X-Ray Observations of NGC 4945

    Science.gov (United States)

    Madejski, G.; Zycki, P.; Done, C.; Valinia, A.; Blanco, P.; Rothschild, R.; Turek, B.

    2000-01-01

    NGC 4945 is one of the brightest Se.yfert galaxies on the sky at 100 keV, but is completely absorbed below 10 keV, implying an optical depth of the absorber to electron scattering of a few; its absorption column is probably the largest which still allows a direct view of the nucleus at hard X-ray energies. Our observations of it with the Rossi X-ray Timing Explorer (RXTE) satellite confirm the large absorption, which for a simple phenomenological fit using an absorber with Solar abundances implies a column of 4.5(sup 0.4, sub -0.4) x 10(exp 24) /sq cm. Using a a more realistic scenario (requiring Monte Carlo modeling of the scattering), we infer the optical depth to Thomson scattering of approximately 2.4. If such a scattering medium were to subtend a large solid angle from the nucleus, it should smear out any intrinsic hard X-ray variability on time scales shorter than the light travel time through it. The rapid (with a time scale of approximately a day) hard X-ray variability of NGC 4945 we observed with the RXTE implies that the bulk of the extreme absorption in this object does not originate in a parsec-size, geometrically thick molecular torus. Limits on the amount of scattered flux require that the optically thick material on parsec scales must be rather geometrically thin, subtending a half-angle < 10 deg. This is only marginally consistent with the recent determinations of the obscuring column in hard X-rays, where only a quarter of Seyfert 2s have columns which are optically thick, and presents a problem in accounting for the Cosmic X-ray Background primarily with AGN possessing the geometry as that inferred by us. The small solid angle of the obscuring material, together with the black hole mass (of approximately 1.4 x 10(exp 6) solar mass) from megamaser measurements. allows a robust determination of the source luminosity, which in turn implies that the source radiates at approximately 10% of the Eddington limit.

  19. Extreme Gaseous Outflows in Radio-Loud Narrow-Line Seyfert 1 Galaxies

    Science.gov (United States)

    Komossa, S.; Xu, D. W.; Wagner, A. Y.

    2018-04-01

    We present four radio-loud NLS1 galaxies with extreme emission-line shifts, indicating radial outflow velocities of the ionized gas of up to 2450 km/s, above the escape velocity of the host galaxies. The forbidden lines show strong broadening, up to 2270 km/s. An ionization stratification (higher line shift at higher ionization potential) implies that we see a large-scale outflow rather than single, localized jet-cloud interactions. Similarly, the paucity of zero-velocity [OIII]λ5007 emitting gas implies the absence of a second narrow-line region (NLR) component at rest, and therefore a large part of the high-ionization NLR is affected by the outflow. Given the radio loudness of these NLS1 galaxies, the observations are consistent with a pole on view onto their central engines, so that the effects of polar outflows are maximized. In addition, a very efficient driving mechanism is required, to reach the high observed velocities. We explore implications from recent hydrodynamic simulations of the interaction between fast winds or jets with the large-scale NLR. Overall, the best agreement with observations (and especially the high outflow speeds of the [NeV] emitting gas) can be reached if the NLS1 galaxies are relatively young sources with lifetimes not much exceeding 1 Myr. These systems represent sites of strong feedback at NLR scales at work, well below redshift one.

  20. HII regions in IC 1613: The ISM in a nearby dwarf irregular galaxy

    Science.gov (United States)

    Price, Jill S.; Mason, Stephen F.; Gullixson, Craig A.

    1990-01-01

    IC 1613, a nearby (725 kpc distant) dwarf irregular galaxy, has always been known to contain large, ring-shaped HII regions in its northeast corner. A new H alpha image has been obtained using the Bell Labs Charge Coupled Device (CCD) camera, an RCA 320 X 512 pixel-thinned, back-illuminated CCD, an H alpha filter of central wavelength 6562 A and width (full width half maximum) of 30 A, and the 42 inch telescope at Lowell Observatory. The low resolution images exhibit many new, faint features.

  1. Search for cold and hot gas in the ram pressure stripped Virgo dwarf galaxy IC 3418

    Czech Academy of Sciences Publication Activity Database

    Jáchym, Pavel; Kenney, J.D.P.; Růžička, Adam; Sun, M.; Combes, F.; Palouš, Jan

    2013-01-01

    Roč. 556, August (2013), A99/1-A99/15 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GPP209/11/P699; GA ČR GAP209/12/1795 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100031203 Program:M Institutional support: RVO:67985815 Keywords : VCC 1217/IC 3418 * Virgo * evolution of galaxies Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.479, year: 2013

  2. Galaxies

    International Nuclear Information System (INIS)

    1989-01-01

    In studies of the large scale structure of the universe there is a continuing need for extensive galaxy redshift determinations. Optically selected redshift surveys are of particular importance, since flux-limited samples record much higher space densities of galaxies than samples of similar size selected in other wavebands. A considerable amount of the South African Astronomical Observatory (SAAO) observing time is currently being devoted to carrying out a large southern galaxy redshift survey. A recently completed study, the Durham-SAAO redshift survey suggests that the mean density of matter is well below the critical limit for a closed universe and also that the universe may be homogenous at very large scales. Other research conducted by the SAAO include studies on: the distribution of galaxies; Seyfert galaxies; starburst and IRAS galaxies; interacting and compact galaxies; a re-evaluation of the Cepheid distance to NGC 300, and a search for quasars behind galaxies. 1 fig

  3. Galaxies

    International Nuclear Information System (INIS)

    1987-01-01

    The size and nature of any large-scale anisotropy in the three-dimensional distribution of galaxies is still little understood. Recent studies have indicated that large fluctuations in the matter distribution on a scale from tens up to several hundreds of megaparsecs may exist. Work at the South African Astronomical Observatory (SAAO) in recent years has made major contributions to studies of the large scale distribution of galaxies, as well as to solving the problems of the galactic and extragalactic distance scale. Other studies of galaxies undertaken at SAAO include: quasars in the fields of nearby galaxies; dwarf irregular galaxies; IRAS galaxies; Seyfert galaxies; 'hot spot' galaxies; supernovae in NGC 5128 and NGC 1559 and superclusters. 4 figs

  4. LLAMA: normal star formation efficiencies of molecular gas in the centres of luminous Seyfert galaxies

    Science.gov (United States)

    Rosario, D. J.; Burtscher, L.; Davies, R. I.; Koss, M.; Ricci, C.; Lutz, D.; Riffel, R.; Alexander, D. M.; Genzel, R.; Hicks, E. H.; Lin, M.-Y.; Maciejewski, W.; Müller-Sánchez, F.; Orban de Xivry, G.; Riffel, R. A.; Schartmann, M.; Schawinski, K.; Schnorr-Müller, A.; Saintonge, A.; Shimizu, T.; Sternberg, A.; Storchi-Bergmann, T.; Sturm, E.; Tacconi, L.; Treister, E.; Veilleux, S.

    2018-02-01

    Using new Atacama Pathfinder Experiment and James Clerk Maxwell Telescope spectroscopy of the CO 2→1 line, we undertake a controlled study of cold molecular gas in moderately luminous (Lbol = 1043-44.5 erg s-1) active galactic nuclei (AGN) and inactive galaxies from the Luminous Local AGN with Matched Analogs (LLAMA) survey. We use spatially resolved infrared photometry of the LLAMA galaxies from 2MASS, the Wide-field Infrared Survey Explorer the Infrared Astronomical Satellite and the Herschel Space Observatory (Herschel), corrected for nuclear emission using multicomponent spectral energy distribution fits, to examine the dust-reprocessed star formation rates, molecular gas fractions and star formation efficiencies (SFEs) over their central 1-3 kpc. We find that the gas fractions and central SFEs of both active and inactive galaxies are similar when controlling for host stellar mass and morphology (Hubble type). The equivalent central molecular gas depletion times are consistent with the discs of normal spiral galaxies in the local Universe. Despite energetic arguments that the AGN in LLAMA should be capable of disrupting the observable cold molecular gas in their central environments, our results indicate that nuclear radiation only couples weakly with this phase. We find a mild preference for obscured AGN to contain higher amounts of central molecular gas, which suggests connection between AGN obscuration and the gaseous environment of the nucleus. Systems with depressed SFEs are not found among the LLAMA AGN. We speculate that the processes that sustain the collapse of molecular gas into dense pre-stellar cores may also be a prerequisite for the inflow of material on to AGN accretion discs.

  5. IR Observations of a Complete Unbiased Sample of Bright Seyfert Galaxies

    Science.gov (United States)

    Malkan, Matthew; Bendo, George; Charmandaris, Vassilis; Smith, Howard; Spinoglio, Luigi; Tommasin, Silvia

    2008-03-01

    IR spectra will measure the 2 main energy-generating processes by which galactic nuclei shine: black hole accretion and star formation. Both of these play roles in galaxy evolution, and they appear connected. To obtain a complete sample of AGN, covering the range of luminosities and column-densities, we will combine 2 complete all-sky samples with complementary selections, minimally biased by dust obscuration: the 116 IRAS 12um AGN and the 41 Swift/BAT hard Xray AGN. These galaxies have been extensively studied across the entire EM spectrum. Herschel observations have been requested and will be synergistic with the Spitzer database. IRAC and MIPS imaging will allow us to separate the nuclear and galactic continua. We are completing full IR observations of the local AGN population, most of which have already been done. The only remaining observations we request are 10 IRS/HIRES, 57 MIPS-24 and 30 IRAC pointings. These high-quality observations of bright AGN in the bolometric-flux-limited samples should be completed, for the high legacy value of complete uniform datasets. We will measure quantitatively the emission at each wavelength arising from stars and from accretion in each galactic center. Since our complete samples come from flux-limited all-sky surveys in the IR and HX, we will calculate the bi-variate AGN and star formation Luminosity Functions for the local population of active galaxies, for comparison with higher redshifts.Our second aim is to understand the physical differences between AGN classes. This requires statistical comparisons of full multiwavelength observations of complete representative samples. If the difference between Sy1s and Sy2s is caused by orientation, their isotropic properties, including those of the surrounding galactic centers, should be similar. In contrast, if they are different evolutionary stages following a galaxy encounter, then we may find observational evidence that the circumnuclear ISM of Sy2s is relatively younger.

  6. Near-IR TRGB Distance Modulus of Dwarf Irregular Galaxy IC 1613

    Directory of Open Access Journals (Sweden)

    M. Y. Jung

    2009-12-01

    Full Text Available The JHKs magnitudes of the red giant branch tip (TRGB and the distance moduli of the nearby dwarf irregular galaxy IC 1613 have been determined from the nearinfrared luminosity functions (LFs of the resolved stars in the galaxy. Applying a Savitzky-Golay filtering, we derived the second derivatives of the LFs, and estimated the apparent magnitudes of the TRGB as mJ = 19.1, mH = 18.4, and mKs = 18:0. The mean values of the theoretical absolute magnitudes of the TRGB were measured by using the Yonsei-Yale isochrones with a metallicity range of -2.1 < [Fe/H] < -0.5 and age of 12 Gyr. The derived values of near-infrared TRGB distance moduli for IC 1613 are (m-M = 24.12±0:25, 24.20±0.44, and 24.00±0.52 for J;H, and Ks bands, respectively.

  7. Complex optical/UV and X-ray variability of the Seyfert 1 galaxy 1H 0419-577

    Science.gov (United States)

    Pal, Main; Dewangan, Gulab C.; Kembhavi, Ajit K.; Misra, Ranjeev; Naik, Sachindra

    2018-01-01

    We present detailed broad-band UV/optical to X-ray spectral variability of the Seyfert 1 galaxy 1H 0419-577 using six XMM-Newton observations performed during 2002-2003. These observations covered a large amplitude variability event in which the soft X-ray (0.3-2 keV) count rate increased by a factor of ∼4 in six months. The X-ray spectra during the variability are well described by a model consisting of a primary power law, blurred and distant reflection. The 2-10 keV power-law flux varied by a factor of ∼7 while the 0.3-2 keV soft X-ray excess flux derived from the blurred reflection component varied only by a factor of ∼2. The variability event was also observed in the optical and UV bands but the variability amplitudes were only at the 6-10 per cent level. The variations in the optical and UV bands appear to follow the variations in the X-ray band. During the rising phase, the optical bands appear to lag behind the UV band but during the declining phase, the optical bands appear to lead the UV band. Such behaviour is not expected in the reprocessing models where the optical/UV emission is the result of reprocessing of X-ray emission in the accretion disc. The delayed contribution of the broad emission lines in the UV band or the changes in the accretion disc/corona geometry combined with X-ray reprocessing may give rise to the observed behaviour of the variations.

  8. Long term X-ray variability characteristics of the narrow-line Seyfert 1 galaxy RE J1034+396

    Science.gov (United States)

    Chaudhury, K.; Chitnis, V. R.; Rao, A. R.; Singh, K. P.; Bhattacharyya, Sudip; Dewangan, G. C.; Chakraborty, S.; Chandra, S.; Stewart, G. C.; Mukerjee, K.; Dey, R. K.

    2018-05-01

    We present the results of our study of the long term X-ray variability characteristics of the Narrow Line Seyfert 1 galaxy RE J1034+396. We use data obtained from the AstroSat satellite along with the light curves obtained from XMM-Newton and Swift-XRT. We use the 0.3 - 7.0 keV and 3 - 20 keV data, respectively, from the SXT and the LAXPC of AstroSat. The X-ray spectra in the 0.3 - 20 keV region are well fit with a model consisting of a power-law and a soft excess described by a thermal-Compton emission with a large optical depth, consistent with the earlier reported results. We have examined the X-ray light curves in the soft and hard X-ray bands of SXT and LAXPC, respectively, and find that the variability is slightly larger in the hard band. To investigate the variability characteristics of this source at different time scales, we have used X-ray light curves obtained from XMM-Newton data (200 s to 100 ks range) and Swift-XRT data (1 day to 100 day range) and find that there are evidences to suggest that the variability sharply increases at longer time scales. We argue that the mass of the black hole in RE J1034+396 is likely to be ˜3 × 106 M⊙, based on the similarity of the observed QPO to the high frequency QPO seen in the Galactic black hole binary, GRS 1915+105.

  9. The Swift Burst Alert Telescope Detected Seyfert 1 Galaxies: X-Ray Broadband Properties and Warm Absorbers

    Science.gov (United States)

    Winter, Lisa M.; Veilleux, Sylvain; McKernan, Barry; Kallman, T.

    2012-01-01

    We present results from an analysis of the broadband, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey conducted in the 14-195 keV band. Therefore, our sources are largely unbiased toward both obscuration and host galaxy properties. Our detailed and uniform model fits to Suzaku/BAT and XMM-Newton/BAT spectra include the neutral absorption, direct power-law, reflected emission, soft excess, warm absorption, and narrow Fe I K[alpha] emission properties for the entire sample. We significantly detect O VII and O VIII edges in 52% of our sample. The strength of these detections is strongly correlated with the neutral column density measured in the spectrum. Among the strongest detections, X-ray grating and UV observations, where available, indicate outflowing material. The ionized column densities of sources with O VII and O VIII detections are clustered in a narrow range with Nwarm [approx] 1021 cm-2, while sources without strong detections have column densities of ionized gas an order of magnitude lower. Therefore, we note that sources without strong detections likely have warm ionized outflows present but at low column densities that are not easily probed with current X-ray observations. Sources with strong complex absorption have a strong soft excess, which may or may not be due to difficulties in modeling the complex spectra of these sources. Still, the detection of a flat [Gamma] [approx] 1 and a strong soft excess may allow us to infer the presence of strong absorption in low signal-to-noise active galactic nucleus spectra. Additionally, we include a useful correction from the Swift BAT luminosity to bolometric luminosity, based on a comparison of our spectral fitting results with published spectral energy distribution fits from 33 of our sources.

  10. Correlated X-ray/UV/optical emission and short-term variability in a Seyfert 1 galaxy NGC 4593

    Science.gov (United States)

    Pal, Main; Naik, Sachindra

    2018-03-01

    We present a detailed multifrequency analysis of an intense monitoring programme of Seyfert 1 galaxy NGC 4593 over a duration of nearly for a month with Swift observatory. We used 185 pointings to study the variability in six ultraviolet/optical and two soft (0.3-1.5 keV) and hard X-ray (1.5-10 keV) bands. The amplitude of the observed variability is found to decrease from high energy to low energy (X-ray to optical) bands. Count-count plots of ultraviolet/optical bands with hard X-rays clearly suggest the presence of a mixture of two major components: (i) highly variable component such as hard X-ray emission, and (ii) slowly varying disc-like component. The variations observed in the ultraviolet/optical emission are strongly correlated with the hard X-ray band. Cross-correlation analysis provides the lags for the longer wavelengths compared to the hard X-rays. Such lags clearly suggest that the changes in the ultraviolet/optical bands follow the variations in the hard X-ray band. This implies that the observed variation in longer wavelengths is due to X-ray reprocessing. Though, the measured lag spectrum (lag versus wavelength) is well described by λ4/3 as expected from the standard disc model, the observed lags are found to be longer than the predicted values from standard disc model. This implies that the actual size of the disc of NGC 4593 is larger than the estimated size of standard thin disc as reported in active galactic nuclei such as NGC 5548 and Fairall 9.

  11. Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1

    Science.gov (United States)

    Bruhweiler, F.; Verner, E.

    2008-03-01

    We use the narrow-lined broad-line region (BLR) of the Seyfert 1 galaxy, I Zw 1, as a laboratory for modeling the ultraviolet (UV) Fe II 2100-3050 Å emission complex. We calculate a grid of Fe II emission spectra representative of BLR clouds and compare them with the observed I Zw 1 spectrum. Our predicted spectrum for log [nH/(cm -3) ] = 11.0, log [ΦH/(cm -2 s-1) ] = 20.5, and ξ/(1 km s-1) = 20, using Cloudy and an 830 level model atom for Fe II with energies up to 14.06 eV, gives a better fit to the UV Fe II emission than models with fewer levels. Our analysis indicates (1) the observed UV Fe II emission must be corrected for an underlying Fe II pseudocontinuum; (2) Fe II emission peaks can be misidentified as that of other ions in active galactic nuclei (AGNs) with narrow-lined BLRs possibly affecting deduced physical parameters; (3) the shape of 4200-4700 Å Fe II emission in I Zw 1 and other AGNs is a relative indicator of narrow-line region (NLR) and BLR Fe II emission; (4) predicted ratios of Lyα, C III], and Fe II emission relative to Mg II λ2800 agree with extinction corrected observed I Zw 1 fluxes, except for C IV λ1549 (5) the sensitivity of Fe II emission strength to microturbulence ξ casts doubt on existing relative Fe/Mg abundances derived from Fe II (UV)/Mg II flux ratios. Our calculated Fe II emission spectra, suitable for BLRs in AGNs, are available at http://iacs.cua.edu/people/verner/FeII. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 05-26555.

  12. The mass of the central black hole in the nearby Seyfert galaxy NGC 5273

    Energy Technology Data Exchange (ETDEWEB)

    Bentz, Misty C.; Horenstein, Daniel; Bazhaw, Craig; Manne-Nicholas, Emily R.; Ou-Yang, Benjamin J.; Anderson, Matthew; Jones, Jeremy; Norris, Ryan P.; Parks, J. Robert; Saylor, Dicy; Teems, Katherine G.; Turner, Clay, E-mail: bentz@astro.gsu.edu [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 600, Atlanta, GA 30303 (United States)

    2014-11-20

    We present the results of a reverberation-mapping program targeting NGC 5273, a nearby early-type galaxy with a broad-lined active galactic nucleus (AGN). Over the course of the monitoring program, NGC 5273 showed strong variability that allowed us to measure time delays in the responses of the broad optical recombination lines to changes in the continuum flux. A weighted average of these measurements results in a black hole mass determination of M {sub BH} = (4.7 ± 1.6) × 10{sup 6} M {sub ☉}. An estimate of the size of the black hole sphere of influence in NGC 5273 puts it just at the limit of the resolution achievable with current ground-based large aperture telescopes. NGC 5273 is therefore an important future target for a black hole mass determination from stellar dynamical modeling, especially because it is the only nearby early-type galaxy hosting an AGN with a reverberation-based mass, allowing the best comparison for the masses determined from these two techniques.

  13. Probing the Physics of Narrow-line Regions in Active Galaxies. IV. Full Data Release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Adam D.; Dopita, Michael A.; Davies, Rebecca; Hampton, Elise; Kewley, Lisa; Banfield, Julie; Groves, Brent; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Sairam, Lalitha [Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034 (India); James, Bethan L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Jin, Chichuan [Max-Planck-Institut für Extraterrestrische Physik, Garching (Germany); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Kharb, Preeti [National Centre for Radio Astrophysics—Tata Institute of Fundamental Research, Pune University Campus, Post Bag 3, Ganeshkhind Pune 411007 (India); Scharwächter, Julia [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, Hawaii 96720 (United States); Shalima, P. [Regional Institute of Education, Manasagangotri, Mysore 570006 (India); Sundar, M. N. [Jain University, 3rd Block Jayanagar, Bengaluru 560011 (India); Zaw, Ingyin, E-mail: adam.thomas@anu.edu.au [New York University (Abu Dhabi), 70 Washington Sq. S, New York, NY 10012 (United States)

    2017-09-01

    We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D emission-line fitting products for the full S7 sample of 131 galaxies. The S7 uses the WiFeS instrument on the ANU 2.3 m telescope to obtain spectra with a spectral resolution of R  = 7000 in the red (540–700 nm) and R  = 3000 in the blue (350–570 nm), over an integral field of 25 × 38 arcsec{sup 2} with 1 × 1 arcsec{sup 2} spatial pixels. The S7 contains both the largest sample of active galaxies and the highest spectral resolution of any comparable integral field survey to date. The emission-line fitting products include line fluxes, velocities, and velocity dispersions across the WiFeS field of view, and an artificial neural network has been used to determine the optimal number of Gaussian kinematic components for emission-lines in each spaxel. Broad Balmer lines are subtracted from the spectra of nuclear spatial pixels in Seyfert 1 galaxies before fitting the narrow lines. We bin nuclear spectra and measure reddening-corrected nuclear fluxes of strong narrow lines for each galaxy. The nuclear spectra are classified on optical diagnostic diagrams, where the strength of the coronal line [Fe vii] λ 6087 is shown to be correlated with [O iii]/H β . Maps revealing gas excitation and kinematics are included for the entire sample, and we provide notes on the newly observed objects.

  14. Broad Paschen-alpha emission in two extremely infrared luminous Seyfert 2 galaxies

    International Nuclear Information System (INIS)

    Hines, D.C.

    1991-01-01

    The Paschen-alpha emission line in the extremely luminous IRAS-selected galaxies IRAS 20460 + 1925 and IRAS 23060 + 0505 is observed. The observed width of H-α of Pa-α in IRAS 20460 + 1925 is 3300 km/s, with a possible broader component of about 3860 km/s, while the observed width of H-α of Pa-α in IRAS 23060 + 0505 is 3270 km/s, with a possible broader component of about 4780 km/s. Considering these results as well as their bolometric luminosities, IRAS 20460 + 1925 and IRAS 23060 + 0505 are proposed to be classified as QSO's. It is suggested that there is a population of obscured QSO's, and that they can be selected by their warmth infrared energy distributions and QSO-like luminosities. 17 refs

  15. A Search for Blazar-Like Radio-Loud Narrow-Line Seyfert 1 Galaxies

    Directory of Open Access Journals (Sweden)

    Hugh R. Miller

    2017-03-01

    Full Text Available We report the results of an observational program to investigate the gamma-ray and optical variability properties of the vRL NLSY1 galaxies listed in the Yuan et al. sample. We have identified 17 members of the Yuan et al. sample possibly associated with gamma-ray sources based on a combination of their optical polarization and optical variability and their gamma-ray properties. Eight have previously been associated with gamma-ray sources. We find nine additional members that we predict are excellent candidates to be associated with gamma-ray sources in the future. All 17 sources have many properties in common with flat spectrum radio quasars (FSRQs, suggesting that they may, in fact, constitute a new subclass of FSRQs.

  16. Exploring the Powerful Ionised Wind in the Seyfert Galaxy PG1211+143

    Science.gov (United States)

    Pounds, Ken

    2013-10-01

    Highly-ionised high-speed winds in AGN (UFOs) were first detected with XMM-Newton a decade ago, and are now established as a key factor in the study of SMBH accretion, and in the growth and metal enrichment of their host galaxies. However, information on the ionisation and dynamical structure, and the ultimate fate of UFOs remains very limited. We request a 600ks extended XMM-Newton study of the prototype UFO PG1211+143 in AO-13, to obtain high quality EPIC and RGS spectra, to map the flow structure and variability, while seeking evidence for the anticipated interaction with the ISM and possible conversion of the energetic wind to a momentum-driven flow.

  17. The X-ray Power Density Spectrum of the Seyfert 2 Galaxy NGC 4945: Analysis and Application of the Method of Light Curve Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Martin; /SLAC

    2010-12-16

    The study of the power density spectrum (PDS) of fluctuations in the X-ray flux from active galactic nuclei (AGN) complements spectral studies in giving us a view into the processes operating in accreting compact objects. An important line of investigation is the comparison of the PDS from AGN with those from galactic black hole binaries; a related area of focus is the scaling relation between time scales for the variability and the black hole mass. The PDS of AGN is traditionally modeled using segments of power laws joined together at so-called break frequencies; associations of the break time scales, i.e., the inverses of the break frequencies, with time scales of physical processes thought to operate in these sources are then sought. I analyze the Method of Light Curve Simulations that is commonly used to characterize the PDS in AGN with a view to making the method as sensitive as possible to the shape of the PDS. I identify several weaknesses in the current implementation of the method and propose alternatives that can substitute for some of the key steps in the method. I focus on the complications introduced by uneven sampling in the light curve, the development of a fit statistic that is better matched to the distributions of power in the PDS, and the statistical evaluation of the fit between the observed data and the model for the PDS. Using archival data on one AGN, NGC 3516, I validate my changes against previously reported results. I also report new results on the PDS in NGC 4945, a Seyfert 2 galaxy with a well-determined black hole mass. This source provides an opportunity to investigate whether the PDS of Seyfert 1 and Seyfert 2 galaxies differ. It is also an attractive object for placement on the black hole mass-break time scale relation. Unfortunately, with the available data on NGC 4945, significant uncertainties on the break frequency in its PDS remain.

  18. FERMI/LAT OBSERVATIONS OF SWIFT/BAT SEYFERT GALAXIES: ON THE CONTRIBUTION OF RADIO-QUIET ACTIVE GALACTIC NUCLEI TO THE EXTRAGALACTIC γ-RAY BACKGROUND

    International Nuclear Information System (INIS)

    Teng, Stacy H.; Mushotzky, Richard F.; Reynolds, Christopher S.; Sambruna, Rita M.; Davis, David S.

    2011-01-01

    We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R X,BAT where radio-loud objects have log R X,BAT > –4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be ∼2 × 10 –11 photons cm –2 s –1 , approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the γ-ray (1-100 GeV) luminosity of ∼ 41 erg s –1 . In addition, we identified 120 new Fermi/LAT sources near the Swift/BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

  19. GEMINI NEAR INFRARED FIELD SPECTROGRAPH OBSERVATIONS OF THE SEYFERT 2 GALAXY MRK 573: IN SITU ACCELERATION OF IONIZED AND MOLECULAR GAS OFF FUELING FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Travis C.; Straughn, A. N. [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Machuca, C.; Crenshaw, D. M.; Baron, F.; Revalski, M.; Pope, C. L. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, 25 Park Place, Suite 605, Atlanta, GA 30303 (United States); Diniz, M. R.; Riffel, R. A. [Departamento de Física, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Kraemer, S. B. [Institute for Astrophysics and Computational Sciences, Department of Physics, The Catholic University of America, Washington, DC 20064 (United States); Schmitt, H. R. [Naval Research Laboratory, Washington, DC 20375 (United States); Storchi-Bergmann, T., E-mail: travis.c.fischer@nasa.gov [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, IF, CP 15051, 91501-970 Porto Alegre, RS (Brazil)

    2017-01-01

    We present near-infrared and optical emission-line and stellar kinematics of the Seyfert 2 galaxy Mrk 573 using the Near-Infrared Field Spectrograph (NIFS) at Gemini North and Dual Imaging Spectrograph at Apache Point Observatory, respectively. By obtaining full kinematic maps of the infrared ionized and molecular gas and stellar kinematics in a ∼700 × 2100 pc{sup 2} circumnuclear region of Mrk 573, we find that kinematics within the Narrow-Line Region are largely due to a combination of both rotation and in situ acceleration of material originating in the host disk. Combining these observations with large-scale, optical long-slit spectroscopy that traces ionized gas emission out to several kpcs, we find that rotation kinematics dominate the majority of the gas. We find that outflowing gas extends to distances less than 1 kpc, suggesting that outflows in Seyfert galaxies may not be powerful enough to evacuate their entire bulges.

  20. Fermi/LAT Observations of Swift/BAT Seyfert Galaxies: On the Contribution of Radio-Quiet Active Galactic Nuclei to the Extragalactic gamma-Ray Background

    Science.gov (United States)

    Teng, Stacy H.; Mushotzky, Richard F.; Sambruna, Rita M.; Davis, David S.; Reynolds, Christopher S.

    2011-01-01

    We present the analysis of 2.1 years of Fermi Large Area Telescope (LAT) data on 491 Seyfert galaxies detected by the Swift Burst Alert Telescope (BAT) survey. Only the two nearest objects, NGC 1068 and NGC 4945, which were identified in the Fermi first year catalog, are detected. Using Swift/BAT and radio 20 cm fluxes, we define a new radio-loudness parameter R(sub X,BAT) where radio-loud objects have logR(sub X,BAT) > -4.7. Based on this parameter, only radio-loud sources are detected by Fermi/LAT. An upper limit to the flux of the undetected sources is derived to be approx.2x10(exp -11) photons/sq cm/s, approximately seven times lower than the observed flux of NGC 1068. Assuming a median redshift of 0.031, this implies an upper limit to the gamma-ray (1-100 GeV) luminosity of BAT Seyfert galaxies with significant Fermi/LAT detections. A majority of these objects do not have Swift/BAT counterparts, but their possible optical counterparts include blazars, flat-spectrum radio quasars, and quasars.

  1. X-ray monitoring of the radio and γ-ray loud Narrow-Line Seyfert 1 Galaxy PKS2004–447

    Directory of Open Access Journals (Sweden)

    Kreikenbohm A.

    2013-12-01

    Full Text Available We present preliminary results of the X-ray analysis of XMM-Newton and Swift observations as part of a multi-wavelength monitoring campaign in 2012 of the radio-loud narrow line Seyfert 1 galaxy PKS 2004–447. The source was recently detected in γ-rays by Fermi/LAT among only four other galaxies of that type. The 0:5 – 10 keV X-ray spectrum is well-described by a simple absorbed powerlaw (Γ ∼ 1.6. The source brightness exhibits variability on timescales of months to years with indications for spectral variability, which follows a “bluer-when-brighter” behaviour, similar to blazars.

  2. X-RAY HIGH-RESOLUTION SPECTROSCOPY REVEALS FEEDBACK IN A SEYFERT GALAXY FROM AN ULTRA-FAST WIND WITH COMPLEX IONIZATION AND VELOCITY STRUCTURE

    International Nuclear Information System (INIS)

    Longinotti, A. L.; Krongold, Y.; Guainazzi, M.; Santos-Lleo, M.; Rodriguez-Pascual, P.; Giroletti, M.; Panessa, F.; Costantini, E.

    2015-01-01

    Winds outflowing from active galactic nuclei (AGNs) may carry significant amounts of mass and energy out to their host galaxies. In this paper we report the detection of a sub-relativistic outflow observed in the narrow line Seyfert 1 galaxy IRAS 17020+4544 as a series of absorption lines corresponding to at least five absorption components with an unprecedented wide range of associated column densities and ionization levels and velocities in the range of 23,000–33,000 km s −1 , detected at X-ray high spectral resolution (E/ΔE ∼ 1000) with the ESA's observatory XMM-Newton. The charge states of the material constituting the wind clearly indicate a range of low to moderate ionization states in the outflowing gas and column densities that are significantly lower than observed in highly ionized ultra-fast outflows. We estimate that at least one of the outflow components may carry sufficient energy to substantially suppress star formation and heat the gas in the host galaxy. IRAS 17020+4544 therefore provides an interesting example of feedback by a moderately luminous AGN that is hosted in a spiral galaxy, a case barely envisaged in most evolution models, which often predict that feedback processes take place in massive elliptical galaxies hosting luminous quasars in a post-merger phase

  3. X-RAY HIGH-RESOLUTION SPECTROSCOPY REVEALS FEEDBACK IN A SEYFERT GALAXY FROM AN ULTRA-FAST WIND WITH COMPLEX IONIZATION AND VELOCITY STRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Longinotti, A. L. [Catedrática CONACYT—Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis E. Erro 1, Tonantzintla, Puebla, C.P. 72840, México (Mexico); Krongold, Y. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apartado Postal 70264, 04510 Mexico D.F. (Mexico); Guainazzi, M.; Santos-Lleo, M.; Rodriguez-Pascual, P. [ESAC, P.O. Box, 78 E-28691 Villanueva de la Cañada, Madrid (Spain); Giroletti, M. [INAF Osservatorio di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Panessa, F. [INAF—Istituto di Astrofisica e Planetologia Spaziali di Roma (IAPS), Via del Fosso del Cavaliere 100, I-00133 Roma (Italy); Costantini, E. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands)

    2015-11-10

    Winds outflowing from active galactic nuclei (AGNs) may carry significant amounts of mass and energy out to their host galaxies. In this paper we report the detection of a sub-relativistic outflow observed in the narrow line Seyfert 1 galaxy IRAS 17020+4544 as a series of absorption lines corresponding to at least five absorption components with an unprecedented wide range of associated column densities and ionization levels and velocities in the range of 23,000–33,000 km s{sup −1}, detected at X-ray high spectral resolution (E/ΔE ∼ 1000) with the ESA's observatory XMM-Newton. The charge states of the material constituting the wind clearly indicate a range of low to moderate ionization states in the outflowing gas and column densities that are significantly lower than observed in highly ionized ultra-fast outflows. We estimate that at least one of the outflow components may carry sufficient energy to substantially suppress star formation and heat the gas in the host galaxy. IRAS 17020+4544 therefore provides an interesting example of feedback by a moderately luminous AGN that is hosted in a spiral galaxy, a case barely envisaged in most evolution models, which often predict that feedback processes take place in massive elliptical galaxies hosting luminous quasars in a post-merger phase.

  4. SUBMILLIMETER LINE SPECTRUM OF THE SEYFERT GALAXY NGC 1068 FROM THE HERSCHEL-SPIRE FOURIER TRANSFORM SPECTROMETER

    International Nuclear Information System (INIS)

    Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma; Schirm, Maximilien R. P.; Wilson, Christine D.; Parkin, Tara J.; Glenn, Jason; Kamenetzky, Julia; Rangwala, Naseem; Maloney, Philip R.; Bendo, George J.; Madden, Suzanne C.; Wolfire, Mark G.; Boselli, Alessandro; Cooray, Asantha; Page, Mathew J.

    2012-01-01

    The first complete submillimeter spectrum (190-670 μm) of the Seyfert 2 galaxy NGC 1068 has been observed with the SPIRE Fourier transform spectrometer on board the Herschel Space Observatory. The sequence of CO lines (J up = 4-13), lines from H 2 O, the fundamental rotational transition of hydrogen fluoride, two o-H 2 O + lines, and one line each from CH + and OH + have been detected, together with the two [C I] lines and the [N II] 205 μm line. The observations in both single pointing mode with sparse image sampling and in mapping mode with full image sampling allow us to disentangle two molecular emission components, one due to the compact circumnuclear disk (CND) and one from the extended region encompassing the star-forming ring (SF-ring). Radiative transfer models show that the two CO components are characterized by densities of n(H 2 ) = 10 4.5 and 10 2.9 cm –3 and temperatures of T kin = 100 K and 127 K, respectively. A comparison of the CO line intensities with the photodissociation region (PDR) and X-ray-dominated region (XDR) models, together with the other observational constraints, such as the observed CO surface brightness and the radiation field, indicates that the best explanation for the CO excitation of the CND is an XDR with a density of n(H 2 ) ∼ 10 4 cm –3 and an X-ray flux of 9 erg s –1 cm –2 , consistent with illumination by the active galactic nucleus, while the CO lines in the SF-ring are better modeled by a PDR. The detected water transitions, together with those observed with the Herschel PACS spectrometer, can be modeled by a large velocity gradient model with low temperature (T kin ∼ 40 K) and high density (n(H 2 ) in the range 10 6.7 -10 7.9 cm –3 ). The emission of H 2 O + and OH + are in agreement with PDR models with cosmic-ray ionization. The diffuse ionized atomic component observed through the [N II] 205 μm line is consistent with previous photoionization models of the starburst.

  5. SUBMILLIMETER LINE SPECTRUM OF THE SEYFERT GALAXY NGC 1068 FROM THE HERSCHEL-SPIRE FOURIER TRANSFORM SPECTROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Schirm, Maximilien R. P.; Wilson, Christine D.; Parkin, Tara J. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Glenn, Jason; Kamenetzky, Julia; Rangwala, Naseem; Maloney, Philip R. [Center for Astrophysics and Space Astronomy, 389-UCB, University of Colorado, Boulder, CO 80303 (United States); Bendo, George J. [UK ALMA Regional Centre Node, Jordell Bank Center for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Madden, Suzanne C. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Wolfire, Mark G. [Astronomy Department, University of Maryland, College Park, MD 20742 (United States); Boselli, Alessandro [Laboratoire d' Astrophysique de Marseille-LAM, Universite d' Aix-Marseille and CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cooray, Asantha [Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Page, Mathew J., E-mail: luigi.spinoglio@iaps.inaf.it [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)

    2012-10-20

    The first complete submillimeter spectrum (190-670 {mu}m) of the Seyfert 2 galaxy NGC 1068 has been observed with the SPIRE Fourier transform spectrometer on board the Herschel Space Observatory. The sequence of CO lines (J {sub up} = 4-13), lines from H{sub 2}O, the fundamental rotational transition of hydrogen fluoride, two o-H{sub 2}O{sup +} lines, and one line each from CH{sup +} and OH{sup +} have been detected, together with the two [C I] lines and the [N II] 205 {mu}m line. The observations in both single pointing mode with sparse image sampling and in mapping mode with full image sampling allow us to disentangle two molecular emission components, one due to the compact circumnuclear disk (CND) and one from the extended region encompassing the star-forming ring (SF-ring). Radiative transfer models show that the two CO components are characterized by densities of n(H{sub 2}) = 10{sup 4.5} and 10{sup 2.9} cm{sup -3} and temperatures of T {sub kin} = 100 K and 127 K, respectively. A comparison of the CO line intensities with the photodissociation region (PDR) and X-ray-dominated region (XDR) models, together with the other observational constraints, such as the observed CO surface brightness and the radiation field, indicates that the best explanation for the CO excitation of the CND is an XDR with a density of n(H{sub 2}) {approx} 10{sup 4} cm{sup -3} and an X-ray flux of 9 erg s{sup -1} cm{sup -2}, consistent with illumination by the active galactic nucleus, while the CO lines in the SF-ring are better modeled by a PDR. The detected water transitions, together with those observed with the Herschel PACS spectrometer, can be modeled by a large velocity gradient model with low temperature (T {sub kin} {approx} 40 K) and high density (n(H{sub 2}) in the range 10{sup 6.7}-10{sup 7.9} cm{sup -3}). The emission of H{sub 2}O{sup +} and OH{sup +} are in agreement with PDR models with cosmic-ray ionization. The diffuse ionized atomic component observed through the [N

  6. SUZAKU MONITORING OF THE SEYFERT 1 GALAXY NGC 5548: WARM ABSORBER LOCATION AND ITS IMPLICATION FOR COSMIC FEEDBACK

    International Nuclear Information System (INIS)

    Krongold, Y.; Andrade-Velazquez, M.; Binette, L.; Jimenez-Bailon, E.; Elvis, M.; Nicastro, F.; Brickhouse, N. S.; Liu, Y.; Wilkes, B.; Mathur, S.; Reeves, J. N.; Grupe, D.; McHardy, I. M.; Minezaki, T.; Yoshii, Y.

    2010-01-01

    We present a 2 month Suzaku X-ray monitoring of the Seyfert 1 galaxy NGC 5548. The campaign consists of seven observations (with exposure time of ∼30 ks each), separated by ∼1 week. This paper focus on the X-ray Imaging Spectrometer data of NGC 5548. We analyze the response in the opacity of the gas that forms the well-known ionized absorber in this source for ionizing flux variations. Despite variations by a factor of ∼4 in the impinging continuum, the soft X-ray spectra of the source show little spectral variations, suggesting no response from the ionized absorber. A detailed time modeling of the spectra confirms the lack of opacity variations for an absorbing component with high ionization (U X ∼ -0.85), and high outflow velocity (v out ∼ 1040 km s -1 ), as the ionization parameter was found to be consistent with a constant value during the whole campaign. Instead, the models suggest that the ionization parameter of a low ionization (U X ∼ -2.8), low velocity (v out ∼ 590 km s -1 ) absorbing component might be changing linearly with the ionizing flux, as expected for gas in photoionization equilibrium. However, given the lack of spectral variations among observations, we consider the variations in this component as tentative. Using the lack of variations, we set an upper limit of n e 7 cm -3 for the electron density of the gas forming the high ionization, high velocity component. This implies a large distance from the continuum source (R>0.033 pc; R>5000R S ). If the variations in the low ionization, low velocity component are real, they imply n e >9.8 x 10 4 cm -3 and R 1.2 x 10 56 erg) can be enough to disrupt the interstellar medium, possibly quenching or regulating large-scale star formation. However, the total mass and energy ejected by the wind may still be lower than the one required for cosmic feedback, even when extrapolated to quasar luminosities. Such feedback would require that we are observing the wind before it is fully accelerated.

  7. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

    International Nuclear Information System (INIS)

    Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Dalla Bontà, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Ciroi, S.

    2013-01-01

    The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n e ∼ 10 5 cm –3 ) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

  8. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 610, Atlanta, GA 30303 (United States); Vestergaard, M.; Kilerci-Eser, E. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Dalla Bontà, E.; Ciroi, S. [Dipartimento di Fisica e Astronomia " G. Galilei," Università di Padova, Vicolo dell' Osservatorio 3 I-35122, Padova (Italy)

    2013-12-20

    The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n {sub e} ∼ 10{sup 5} cm{sup –3}) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

  9. Einstein Observatory SSS and MPC observations of the complex X-ray spectra of Seyfert galaxies. [Solid State Spectrometer and Monitor Proportional Counter

    Science.gov (United States)

    Turner, T. J.; Weaver, K. A.; Mushotzky, R. F.; Holt, S. S.; Madejski, G. M.

    1991-01-01

    The X-ray spectra of 25 Seyfert galaxies measured with the Solid State Spectrometer on the Einstein Observatory have been investigated. This new investigation utilizes simultaneous data from the Monitor Proportional Counter, and automatic correction for systematic effects in the Solid State Spectrometer which were previously handled subjectively. It is found that the best-fit single-power-law indices generally agree with those previously reported, but that soft excesses of some form are inferred for about 48 percent of the sources. One possible explanation of the soft excess emission is a blend of soft X-ray lines, centered around 0.8 keV. The implications of these results for accretion disk models are discussed.

  10. ALMA Maps of Dust and Warm Dense Gas Emission in the Starburst Galaxy IC 5179

    Science.gov (United States)

    Zhao, Yinghe; Lu, Nanyao; Díaz-Santos, Tanio; Xu, C. Kevin; Gao, Yu; Charmandaris, Vassilis; van der Werf, Paul; Zhang, Zhi-Yu; Cao, Chen

    2017-08-01

    We present our high-resolution (0.″15 × 0.″13, ˜34 pc) observations of the CO (6-5) line emission, which probes the warm and dense molecular gas, and the 434 μm dust continuum emission in the nuclear region of the starburst galaxy IC 5179, conducted with the Atacama Large Millimeter Array (ALMA). The CO (6-5) emission is spatially distributed in filamentary structures with many dense cores and shows a velocity field that is characteristic of a circumnuclear rotating gas disk, with 90% of the rotation speed arising within a radius of ≲150 pc. At the scale of our spatial resolution, the CO (6-5) and dust emission peaks do not always coincide, with their surface brightness ratio varying by a factor of ˜10. This result suggests that their excitation mechanisms are likely different, as further evidenced by the southwest to northeast spatial gradient of both CO-to-dust continuum ratio and Pa-α equivalent width. Within the nuclear region (radius ˜ 300 pc) and with a resolution of ˜34 pc, the CO line flux (dust flux density) detected in our ALMA observations is 180 ± 18 Jy km s-1 (71 ± 7 mJy), which accounts for 22% (2.4%) of the total value measured by Herschel. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  11. ALMA Maps of Dust and Warm Dense Gas Emission in the Starburst Galaxy IC 5179

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yinghe [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Lu, Nanyao; Xu, C. Kevin [National Astronomical Observatories of China, Chinese Academy of Sciences, Beijing 100012 (China); Díaz-Santos, Tanio [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Gao Yu [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Charmandaris, Vassilis [Department of Physics, University of Crete, GR-71003 Heraklion (Greece); Werf, Paul van der [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Zhang Zhi-Yu [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Cao, Chen, E-mail: zhaoyinghe@ynao.ac.cn [School of Space Science and Physics, Shandong University at Weihai, Weihai, Shandong 264209 (China)

    2017-08-10

    We present our high-resolution (0.″15 × 0.″13, ∼34 pc) observations of the CO (6−5) line emission, which probes the warm and dense molecular gas, and the 434 μ m dust continuum emission in the nuclear region of the starburst galaxy IC 5179, conducted with the Atacama Large Millimeter Array (ALMA). The CO (6−5) emission is spatially distributed in filamentary structures with many dense cores and shows a velocity field that is characteristic of a circumnuclear rotating gas disk, with 90% of the rotation speed arising within a radius of ≲150 pc. At the scale of our spatial resolution, the CO (6−5) and dust emission peaks do not always coincide, with their surface brightness ratio varying by a factor of ∼10. This result suggests that their excitation mechanisms are likely different, as further evidenced by the southwest to northeast spatial gradient of both CO-to-dust continuum ratio and Pa- α equivalent width. Within the nuclear region (radius ∼ 300 pc) and with a resolution of ∼34 pc, the CO line flux (dust flux density) detected in our ALMA observations is 180 ± 18 Jy km s{sup −1} (71 ± 7 mJy), which accounts for 22% (2.4%) of the total value measured by Herschel .

  12. H I IMAGING OBSERVATIONS OF SUPERTHIN GALAXIES. II. IC 2233 AND THE BLUE COMPACT DWARF NGC 2537

    International Nuclear Information System (INIS)

    Matthews, Lynn D.; Uson, Juan M.

    2008-01-01

    We have used the Very Large Array to image the H I 21 cm line emission in the edge-on Sd galaxy IC 2233 and the blue compact dwarf NGC 2537. We also present new optical B, R, and Hα imaging of IC 2233 obtained with the WIYN telescope. Despite evidence of localized massive star formation in the form of prominent H II regions and shells, supergiant stars, and a blue integrated color, IC 2233 is a low surface brightness system with a very low global star formation rate (∼ sun yr -1 ), and we detect no significant 21 cm radio continuum emission from the galaxy. The H I and ionized gas disks of IC 2233 are clumpy and vertically distended, with scale heights comparable to that of the young stellar disk. Both the stellar and H I disks of IC 2233 appear flared, and we also find a vertically extended, rotationally anomalous component of H I extending to ∼ 2.4d 10 kpc from the midplane. The H I disk exhibits a mild lopsidedness as well as a global corrugation pattern with a period of ∼7d 10 kpc and an amplitude of ∼150d 10 pc. To our knowledge, this is the first time corrugations of the gas disk have been reported in an external galaxy; these undulations may be linked to bending instabilities or to underlying spiral structure and suggest that the disk is largely self-gravitating. Lying at a projected distance of 16'.7 from IC 2233, NGC 2537 has an H I disk with a bright, tilted inner ring and a flocculent, dynamically cold outer region that extends to ∼3.5 times the extent of the stellar light (D 25 ). Although NGC 2537 is rotationally-dominated, we measure H I velocity dispersions as high as σ V.HI ∼25 km s -1 near its center, indicative of significant turbulent motions. The inner rotation curve rises steeply, implying a strong central mass concentration. Our data indicate that IC 2233 and NGC 2537 do not constitute a bound pair and most likely lie at different distances. We also find no compelling evidence of a recent minor merger in either IC 2233 or NGC

  13. DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masaomi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Morokuma, Tomoki; Doi, Mamoru; Kikuchi, Yuki [Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Itoh, Ryosuke [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Akitaya, Hiroshi; Tanaka, Yasuyuki T.; Kawabata, Koji S. [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, Kobe, Hyogo 658-8501 (Japan); Saito, Yoshihiko; Kawai, Nobuyuki [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Stawarz, Łukasz [Institute of Space and Astronautical Science, JAXA, Sagamihara, Kanagawa 252-5210 (Japan); Gandhi, Poshak [Department of Physics, Durham University, Durham DH1-3LE (United Kingdom); Ali, Gamal; Essam, Ahmad; Hamed, Gamal [National Research Institute of Astronomy and Geophysics, Helwan, Cairo (Egypt); Aoki, Tsutomu [Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, Kiso, Nagano 397-0101 (Japan); Contreras, Carlos; Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Iwata, Ikuru, E-mail: masaomi.tanaka@nao.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); and others

    2014-10-01

    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of ∼10{sup 7} M {sub ☉} implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ≅ 4 × 10{sup 2}-3 × 10{sup 3}, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and γ-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.

  14. Evolved stars in the Local Group galaxies - II. AGB, RSG stars and dust production in IC10

    Science.gov (United States)

    Dell'Agli, F.; Di Criscienzo, M.; Ventura, P.; Limongi, M.; García-Hernández, D. A.; Marini, E.; Rossi, C.

    2018-06-01

    We study the evolved stellar population of the Local Group galaxy IC10, with the aim of characterizing the individual sources observed and to derive global information on the galaxy, primarily the star formation history and the dust production rate. To this aim, we use evolutionary sequences of low- and intermediate-mass (M account for 40% of the sources brighter than the tip of the red giant branch. Most of these stars descend from ˜1.1 - 1.3 M⊙ progenitors, formed during the major epoch of star formation, which occurred ˜2.5 Gyr ago. The presence of a significant number of bright stars indicates that IC10 has been site of significant star formation in recent epochs and currently hosts a group of massive stars in the core helium-burning phase. Dust production in this galaxy is largely dominated by carbon stars; the overall dust production rate estimated is 7 × 10-6 M⊙/yr.

  15. EVN observations of the OH megamaser galaxies Mrk 231 and IC 694

    NARCIS (Netherlands)

    Klockner, HR; Baan, WA; Migenes,; Reid, MJ

    2002-01-01

    We present EVN observations of hydroxyl (OH) main-line emission in two megamaser sources Mrk 231 and IC 694. The observations indicate that the broad maser emission lines originate within the nuclear regions. A single 1667 MHz main-line feature is seen at the nucleus of IC 694. In Mrk 231 both

  16. RAPID INFRARED VARIABILITY OF THREE RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES: A VIEW FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Ning; Zhou Hongyan; Wang Tinggui; Dong Xiaobo; Jiang Peng [Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Chinese Academy of Science, Hefei, Anhui 230026 (China); Ho, Luis C. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Yuan Weimin [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Ji Tuo; Tian Qiguo, E-mail: jnac@mail.ustc.edu.cn [Polar Research Institute of China, 451 Jinqiao Road, Pudong, Shanghai 200136 (China)

    2012-11-10

    Using newly released data from the Wide-field Infrared Survey Explorer, we report the discovery of rapid infrared variability in three radio-loud narrow-line Seyfert 1 galaxies (NLS1s) selected from the 23 sources in the sample of Yuan et al. J0849+5108 and J0948+0022 clearly show intraday variability, while J1505+0326 has a longer measurable timescale within 180 days. Their variability amplitudes, corrected for measurement errors, are {approx}0.1-0.2 mag. The detection of intraday variability restricts the size of the infrared-emitting region to {approx}10{sup -3} pc, significantly smaller than the scale of the torus but consistent with the base of a jet. The three variable sources are exceptionally radio-loud, have the highest radio brightness temperature among the whole sample, and all show detected {gamma}-ray emission in Fermi/LAT observations. Their spectral energy distributions resemble those of low-energy-peaked blazars, with a synchrotron peak around infrared wavelengths. This result strongly confirms the view that at least some radio-loud NLS1s are blazars with a relativistic jet close to our line of sight. The beamed synchrotron emission from the jet contributes significantly to and probably dominates the spectra in the infrared and even optical bands.

  17. MINUTE-SCALE RAPID VARIABILITY OF THE OPTICAL POLARIZATION IN THE NARROW-LINE SEYFERT 1 GALAXY PMN J0948+0022

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Ryosuke; Tanaka, Yasuyuki T.; Fukazawa, Yasushi; Kawaguchi, Kenji; Takaki, Katsutoshi; Ueno, Issei [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kawabata, Koji S.; Moritani, Yuki; Uemura, Makoto; Akitaya, Hiroshi; Yoshida, Michitoshi; Ohsugi, Takashi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Hanayama, Hidekazu; Miyaji, Takeshi [Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, 1024-1 Arakawa, Ishigaki, Okinawa 907-0024 (Japan); Kawai, Nobuyuki, E-mail: itoh@hep01.hepl.hiroshima-u.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2013-09-20

    We report on optical photopolarimetric results of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy PMN J0948+0022 on 2012 December to 2013 February triggered by flux enhancements in the near infrared and γ-ray bands. With the one-shot polarimetry of the Hiroshima One-shot Wide field Polarimeter installed on the Kanata Telescope, we detected very rapid variability in the polarized-flux (PF) light curve on MJD 56281 (2012 December 20). The rise and decay times were about 140 s and 180 s, respectively. The polarization degree (PD) reached 36% ± 3% at the peak of the short-duration pulse, while the polarization angle remained almost constant. In addition, temporal profiles of the total flux and PD showed highly variable but well correlated behavior and discrete correlation function analysis revealed that no significant time lag of more than 10 minutes was present. The high PD and minute-scale variability in PF provides clear evidence of synchrotron radiation from a very compact emission region of ∼10{sup 14} cm size with a highly ordered magnetic field. Such micro-variability of polarization is also observed in several blazar jets, but its complex relation between total flux and PD are explained by a multi-zone model in several blazars. The implied single emission region in PMN J0948+0022 might reflect a difference of jets between RL-NLSy1s and blazars.

  18. VERY LONG BASELINE ARRAY IMAGING OF PARSEC-SCALE RADIO EMISSIONS IN NEARBY RADIO-QUIET NARROW-LINE SEYFERT 1 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Asada, Keiichi; Inoue, Makoto [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Fujisawa, Kenta [The Research Institute of Time Studies, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8511 (Japan); Nagai, Hiroshi; Hagiwara, Yoshiaki [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Wajima, Kiyoaki, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China)

    2013-03-01

    We conducted Very Long Baseline Array (VLBA) observations of seven nearby narrow-line Seyfert 1 (NLS1) galaxies at 1.7 GHz ({lambda}18 cm) with milliarcsecond resolution. This is the first systematic very long baseline interferometry study focusing on the central parsec-scale regions of radio-quiet NLS1s. Five of the seven were detected at a brightness temperature of {approx}> 5 Multiplication-Sign 10{sup 6} K and contain radio cores with high brightness temperatures of >6 Multiplication-Sign 10{sup 7} K, indicating a nonthermal process driven by jet-producing central engines as in radio-loud NLS1s and other active galactic nucleus classes. VLBA images of MRK 1239, MRK 705, and MRK 766 exhibit parsec-scale jets with clear linear structures. A large portion of the radio power comes from diffuse emission components that are distributed within the nuclear regions ({approx}< 300 pc), which is a common characteristic throughout the observed NLS1s. Jet kinetic powers limited by the Eddington limit may be insufficient to allow the jets to escape to kiloparsec scales for these radio-quiet NLS1s with low-mass black holes of {approx}< 10{sup 7} M {sub Sun }.

  19. Survey of Water and Ammonia in Nearby Galaxies (SWAN): Resolved Ammonia Thermometry and Water and Methanol Masers in IC 342, NGC 6946, and NGC 2146

    Science.gov (United States)

    Gorski, Mark; Ott, Jürgen; Rand, Richard; Meier, David S.; Momjian, Emmanuel; Schinnerer, Eva

    2018-04-01

    The Survey of Water and Ammonia in Nearby galaxies (SWAN) studies atomic and molecular species across the nuclei of four star-forming galaxies: NGC 253, IC 342, NGC 6946, and NGC 2146. As part of this survey, we present Karl G. Jansky Very Large Array molecular line observations of three galaxies: IC 342, NGC 6946, and NGC 2146. NGC 253 is covered in a previous paper. These galaxies were chosen to span an order of magnitude in star formation rates and to select a variety of galaxy types. We target the metastable transitions of ammonia NH3(1, 1) to (5, 5), the 22 GHz water (H2O) (616–523) transition, and the 36.1 GHz methanol (CH3OH) (4‑1–30) transition. We use the NH3 metastable lines to perform thermometry of the dense molecular gas. We show evidence for uniform heating across the central kiloparsec of IC 342 with two temperature components for the molecular gas, similar to NGC 253, of 27 and 308 K, and that the dense molecular gas in NGC 2146 has a temperature 36 GHz CH3OH masers in IC 342 and NGC 6946. For the four external galaxies the total CH3OH luminosity in each galaxy suggests a correlation with galactic star formation rate, whereas the morphology of the emission is similar to that of HNCO, a weak shock tracer.

  20. Optical observations of the nearby galaxy IC342 with narrow band [SII] and hα filters. II - detection of 16 optically-identified supernova remnant candidates

    Directory of Open Access Journals (Sweden)

    Vučetić M.M.

    2015-01-01

    Full Text Available We present the detection of 16 optical supernova remnant (SNR candidates in the nearby spiral galaxy IC342. The candidates were detected by applying the [Sii]/Hα ratio criterion on observations made with the 2 m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper, we report the coordinates, diameters, Hα and [S ii] fluxes for 16 SNRs detected in two fields of view in the IC342 galaxy. Also, we estimate the contamination of total Hα flux from SNRs in the observed portion of IC342 to be 1.4%. This would represent the fractional error when the star formation rate (SFR for this galaxy is derived from the total galaxy’s Hα emission.

  1. Short-term radio variability and parsec-scale structure in A gamma-ray narrow-line Seyfert 1 galaxy 1H 0323+342

    Energy Technology Data Exchange (ETDEWEB)

    Wajima, Kiyoaki [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Xuhui District, Shanghai 200030 (China); Fujisawa, Kenta [The Research Institute for Time Studies, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8511 (Japan); Hayashida, Masaaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Isobe, Naoki [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Ishida, Takafumi [Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8512 (Japan); Yonekura, Yoshinori, E-mail: kwajima@shao.ac.cn [Center for Astronomy, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan)

    2014-02-01

    We made simultaneous single-dish and very long baseline interferometer (VLBI) observations of a narrow-line Seyfert 1 galaxy 1H 323+342, showing gamma-ray activity revealed by Fermi/Large Area Telescope observations. We found significant variation of the total flux density at 8 GHz on the timescale of one month by the single-dish monitoring. The total flux density varied by 5.5% in 32 days, which is comparable to the gamma-ray variability timescale, corresponding to the variability brightness temperature of 7.0 × 10{sup 11} K. The source consists of central and southeastern components on the parsec (pc) scale. Only the flux of the central component decreased in the same way as the total flux density, indicating that the short-term radio variability, and probably the gamma-ray-emitting region, is associated with this component. From the VLBI observations, we obtained brightness temperatures of greater than (5.2 ± 0.3) × 10{sup 10} K and derived an equipartition Doppler factor of greater than 1.7, a variability Doppler factor of 2.2, and an 8 GHz radio power of 10{sup 24.6} W Hz{sup –1}. Combining them, we conclude that acceleration of radio jets and creation of high-energy particles are ongoing in the central engine and that the apparent very radio-loud feature of the source is due to the Doppler boosting effect, resulting in the intrinsic radio loudness being an order of magnitude smaller than the observed values. We also conclude that the pc-scale jet represents recurrent activity from the spectral fitting and the estimated kinematic age of pc- and kpc-scale extended components with different position angles.

  2. Broadband spectral study of the jet-disc emission in the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342

    Science.gov (United States)

    Ghosh, Ritesh; Dewangan, Gulab C.; Mallick, Labani; Raychaudhuri, Biplab

    2018-06-01

    We present a broadband spectral study of the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 based on multi-epoch observations performed with NuSTAR on 2014 March 15, and two simultaneous observations performed with Suzaku and Swift on 2009 July 26 and 2013 March 1. We found the presence of a strong soft X-ray excess emission, a broad but weak Fe line and hard X-ray excess emission. We used the blurred reflection (relxill) and the intrinsic disc Comptonization (optxagnf), two physically motivated models, to describe the broadband spectra and to disentangle the disk/corona and jet emission. The relxill model is mainly constrained by the strong soft X-ray excess although the model failed to predict this excess when fitted above 3{keV} and extrapolated to lower energies. The joint spectral analysis of the three datasets above 3{keV} with this model resulted in a high black hole spin (a > 0.9) and moderate reflection fraction R ˜ 0.5. The optxagnf model fitted to the two simultaneous datasets resulted in an excess emission in the UV band. The simultaneous UV-to-hard X-ray spectra of 1H 0323+342 are best described by a model consisting of a primary X-ray power-law continuum with Γ ˜ 1.8, a blurred reflection component with R ˜ 0.5, Comptonised disk emission as the soft X-ray excess, optical/UV emission from a standard accretion disk around a black hole of mass ˜107M⊙ and a steep power law (Γ ˜ 3 - 3.5) component, most likely the jet emission in the UV band. The fractional RMS variability spectra suggest that both the soft excess and the powerlaw component are variable in nature.

  3. A Survey of X-Ray Variability in Seyfert 1 Galaxies with XMM-Newton to study the soft excess and the broad Fe lines

    Science.gov (United States)

    Ponti, Gabriele

    The nature of the soft excess and the presence of the broad Fe lines is still nowadays highly debated because the different absorption/emission models are degenerate. Spectral variability studies have the potential to break this degeneracy. I will present the results of a spectral variability RMS survey of the 36 brightest type 1 Seyfert galaxies observed by XMM-Newton for more than 30 ks. More than 80 as already measured, on longer timescales, with RXTE (Markowitz et al. 2004). About half of the sample show lower variability in the soft energy band, indicating that the emission from the soft excess is more stable than the one of the continuum. While the other sources show a soft excess that is as variable as the continuum. About half of the sample do not show an excess of variability where the warm absorber component imprints its stronger features, suggesting that for these sources the soft excess is not produced by a relativistic absorbing wind. In a few bright and well exposed sources it has been possible to measure an excess of variability at the energy of the broad component of the Fe K line, in agreement with the broad emission line interpretation. For the sources where more than one observation was available the stability of the shape of the RMS spectrum has been investigated. Moreover, it will be presented the results of the computation of the excess variance of all the radio quiet type 1 AGN of the XMM-Newton database. The relations between variability, black hole mass, accretion rate and luminosity are investigated and their scatter measured.

  4. STRONG UV AND X-RAY VARIABILITY OF THE NARROW LINE SEYFERT 1 GALAXY WPVS 007-ON THE NATURE OF THE X-RAY LOW STATE

    Energy Technology Data Exchange (ETDEWEB)

    Grupe, Dirk; Barlow, Brad N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Komossa, S. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Scharwaechter, Julia [Research School of Astronomy and Astrophysics, Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Dietrich, Matthias [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Leighly, Karen M.; Lucy, Adrian, E-mail: dxg35@psu.edu, E-mail: julia.scharwaechter@obspm.fr, E-mail: leighly@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States)

    2013-10-01

    We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS1) galaxy WPVS 007. The galaxy was monitored with Swift between 2005 October and 2013 July, after it had previously undergone a dramatic drop in its X-ray flux. For the first time, we are able to repeatedly detect this NLS1 in X-rays again. This increased number of detections in the last couple of years may suggest that the strong absorber that has been found in this active galactic nucleus (AGN) is starting to become leaky and may eventually disappear. The X-ray spectra obtained for WPVS 007 are all consistent with a partial covering absorber model. A spectrum based on the data during the extreme low X-ray flux states shows that the absorption column density is of the order of 4 Multiplication-Sign 10{sup 23} cm{sup -2} with a covering fraction of 95%. WPVS 007 also displays one of the strongest UV variabilities seen in NLS1s. The UV continuum variability anti-correlates with the optical/UV slope {alpha}{sub UV}, which suggests that the variability may be primarily due to reddening. The UV variability timescales are consistent with moving dust ''clouds'' located beyond the dust sublimation radius of R{sub sub} Almost-Equal-To 20 lt-days. We present for the first time near-infrared JHK data of WPVS 007, which reveal a rich emission-line spectrum. Recent optical spectroscopy does not indicate significant variability in the broad permitted and Fe II emission lines, implying that the ionizing continuum seen by those gas clouds has not significantly changed over the last decades. All X-ray and UV observations are consistent with a scenario in which an evolving broad absorption line (BAL) flow obscures the continuum emission. As such, WPVS 007 is an important target for our understanding of BAL flows in low-mass AGNs.

  5. The Gamma-Ray Emitting Radio-Loud Narrow-Line Seyfert 1 Galaxy PKS 2004-447 II. The Radio View

    Science.gov (United States)

    Schulz, R.; Kreikenbohm, A.; Kadler, M.; Ojha, R.; Ros, E.; Stevens, J.; Edwards, P. G.; Carpenter, B.; Elsaesser, D.; Gehrels, N.; hide

    2016-01-01

    Context. gamma-ray-detected radio-loud narrow-line Seyfert 1 (gamma-NLS1) galaxies constitute a small but interesting sample of the gamma-ray-loud AGN. The radio-loudest gamma-NLS1 known, PKS2004447, is located in the southern hemisphere and is monitored in the radio regime by the multiwavelength monitoring programme TANAMI. Aims. We aim for the first detailed study of the radio morphology and long-term radio spectral evolution of PKS2004447, which are essential for understanding the diversity of the radio properties of gamma-NLS1s. Methods. The TANAMI VLBI monitoring program uses the Australian Long Baseline Array (LBA) and telescopes in Antarctica, Chile, New Zealand, and South Africa to monitor the jets of radio-loud active galaxies in the southern hemisphere. Lower resolution radio flux density measurements at multiple radio frequencies over four years of observations were obtained with the Australia Telescope Compact Array (ATCA). Results. The TANAMI VLBI image at 8.4GHz shows an extended one-sided jet with a dominant compact VLBI core. Its brightness temperature is consistent with equipartition, but it is an order of magnitude below other gamma-NLS1s with the sample value varying over two orders of magnitude. We find a compact morphology with a projected large-scale size 11 kpc and a persistent steep radio spectrum with moderate flux-density variability. Conclusions. PKS2004447 appears to be a unique member of the gamma-NLS1 sample. It exhibits blazar-like features, such as a flat featureless X-ray spectrum and a core-dominated, one-sided parsec-scale jet with indications for relativistic beaming. However, the data also reveal properties atypical for blazars, such as a radio spectrum and large-scale size consistent with compact-steep-spectrum (CSS) objects, which are usually associated with young radio sources. These characteristics are unique among all gamma-NLS1s and extremely rare among gamma-ray-loud AGN.

  6. Exploring the making of a galactic wind in the starbursting dwarf irregular galaxy IC 10 with LOFAR

    Science.gov (United States)

    Heesen, V.; Rafferty, D. A.; Horneffer, A.; Beck, R.; Basu, A.; Westcott, J.; Hindson, L.; Brinks, E.; ChyŻy, K. T.; Scaife, A. M. M.; Brüggen, M.; Heald, G.; Fletcher, A.; Horellou, C.; Tabatabaei, F. S.; Paladino, R.; Nikiel-Wroczyński, B.; Hoeft, M.; Dettmar, R.-J.

    2018-05-01

    Low-mass galaxies are subject to strong galactic outflows, in which cosmic rays may play an important role; they can be best traced with low-frequency radio continuum observations, which are less affected by spectral ageing. We present a study of the nearby starburst dwarf irregular galaxy IC 10 using observations at 140 MHz with the Low-Frequency Array (LOFAR), at 1580 MHz with the Very Large Array (VLA), and at 6200 MHz with the VLA and the 100-m Effelsberg telescope. We find that IC 10 has a low-frequency radio halo, which manifests itself as a second component (thick disc) in the minor axis profiles of the non-thermal radio continuum emission at 140 and 1580 MHz. These profiles are then fitted with 1D cosmic ray transport models for pure diffusion and advection. We find that a diffusion model fits best, with a diffusion coefficient of D = (0.4-0.8) × 1026(E/GeV)0.5 cm2 s-1, which is at least an order of magnitude smaller than estimates both from anisotropic diffusion and the diffusion length. In contrast, advection models, which cannot be ruled out due to the mild inclination, while providing poorer fits, result in advection speeds close to the escape velocity of ≈ 50 km s- 1, as expected for a cosmic ray-driven wind. Our favoured model with an accelerating wind provides a self-consistent solution, where the magnetic field is in energy equipartition with both the warm neutral and warm ionized medium with an important contribution from cosmic rays. Consequently, cosmic rays can play a vital role for the launching of galactic winds in the disc-halo interface.

  7. HIGH STAR FORMATION RATES IN TURBULENT ATOMIC-DOMINATED GAS IN THE INTERACTING GALAXIES IC 2163 AND NGC 2207

    International Nuclear Information System (INIS)

    Elmegreen, Bruce G.; Kaufman, Michele; Bournaud, Frédéric; Juneau, Stéphanie; Elmegreen, Debra Meloy; Struck, Curtis; Brinks, Elias

    2016-01-01

    CO observations of the interacting galaxies IC 2163 and NGC 2207 are combined with HI, H α , and 24 μ m observations to study the star formation rate (SFR) surface density as a function of the gas surface density. More than half of the high-SFR regions are HI dominated. When compared to other galaxies, these HI-dominated regions have excess SFRs relative to their molecular gas surface densities but normal SFRs relative to their total gas surface densities. The HI-dominated regions are mostly located in the outer part of NGC 2207 where the HI velocity dispersion is high, 40–50 km s −1 . We suggest that the star-forming clouds in these regions have envelopes at lower densities than normal, making them predominantly atomic, and cores at higher densities than normal because of the high turbulent Mach numbers. This is consistent with theoretical predictions of a flattening in the density probability distribution function for compressive, high Mach number turbulence.

  8. HIGH STAR FORMATION RATES IN TURBULENT ATOMIC-DOMINATED GAS IN THE INTERACTING GALAXIES IC 2163 AND NGC 2207

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G. [IBM Research Division, T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States); Kaufman, Michele [110 Westchester Rd, Newton, MA 02458 (United States); Bournaud, Frédéric; Juneau, Stéphanie [Laboratoire AIM-Paris-Saclay, CEA/DSM-CNRS-Université Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif sur Yvette (France); Elmegreen, Debra Meloy [Department of Physics and Astronomy, Vassar College, Poughkeepsie, NY 12604 (United States); Struck, Curtis [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Brinks, Elias, E-mail: bge@us.ibm.com, E-mail: kaufmanrallis@icloud.com, E-mail: frederic.bournaud@gmail.com, E-mail: stephanie.juneau@cea.fr, E-mail: elmegreen@vassar.edu, E-mail: struck@iastate.edu, E-mail: e.brinks@herts.ac.uk [University of Hertfordshire, Centre for Astrophysics Research, College Lane, Hatfield AL10 9AB (United Kingdom)

    2016-05-20

    CO observations of the interacting galaxies IC 2163 and NGC 2207 are combined with HI, H α , and 24 μ m observations to study the star formation rate (SFR) surface density as a function of the gas surface density. More than half of the high-SFR regions are HI dominated. When compared to other galaxies, these HI-dominated regions have excess SFRs relative to their molecular gas surface densities but normal SFRs relative to their total gas surface densities. The HI-dominated regions are mostly located in the outer part of NGC 2207 where the HI velocity dispersion is high, 40–50 km s{sup −1}. We suggest that the star-forming clouds in these regions have envelopes at lower densities than normal, making them predominantly atomic, and cores at higher densities than normal because of the high turbulent Mach numbers. This is consistent with theoretical predictions of a flattening in the density probability distribution function for compressive, high Mach number turbulence.

  9. The Near-infrared Tip of the Red Giant Branch. I. A Calibration in the Isolated Dwarf Galaxy IC 1613

    Science.gov (United States)

    Madore, Barry F.; Freedman, Wendy L.; Hatt, Dylan; Hoyt, Taylor J.; Monson, Andrew J.; Beaton, Rachael L.; Rich, Jeffrey A.; Jang, In Sung; Lee, Myung Gyoon; Scowcroft, Victoria; Seibert, Mark

    2018-05-01

    Based on observations from the FourStar near-infrared camera on the 6.5 m Baade-Magellan telescope at Las Campanas, Chile, we present calibrations of the JHK luminosities of stars defining the tip of the red giant branch (TRGB) in the halo of the Local Group dwarf galaxy IC 1613. We employ metallicity-independent (rectified) T-band magnitudes—constructed using J-, H-, and K-band magnitudes and both (J ‑ H) and (J ‑ K) colors to flatten the upward-sloping red giant branch tips as otherwise seen in their apparent color–magnitude diagrams. We describe and quantify the advantages of working at these particular near-infrared wavelengths, which are applicable to both the Hubble Space Telescope (HST) and the James Webb Space Telescope (JWST). We also note that these same wavelengths can be accessed from the ground for an eventual tie-in to Gaia for absolute astrometry and parallaxes to calibrate the intrinsic luminosity of the TRGB. Adopting the color terms derived from the IC 1613 data, as well as the zero points from a companion study of the Large Magellanic Cloud, whose distance is anchored to the geometric distances of detached eclipsing binaries, we find a true distance modulus of 24.32 ± 0.02 (statistical) ±0.05 mag (systematic) for IC 1613, which compares favorably with the recently published multi-wavelength, multi-method consensus modulus of 24.30 ± 0.05 mag by Hatt et al.

  10. A Uniformly Selected Sample of Low-mass Black Holes in Seyfert 1 Galaxies. II. The SDSS DR7 Sample

    Science.gov (United States)

    Liu, He-Yang; Yuan, Weimin; Dong, Xiao-Bo; Zhou, Hongyan; Liu, Wen-Juan

    2018-04-01

    A new sample of 204 low-mass black holes (LMBHs) in active galactic nuclei (AGNs) is presented with black hole masses in the range of (1–20) × 105 M ⊙. The AGNs are selected through a systematic search among galaxies in the Seventh Data Release (DR7) of the Sloan Digital Sky Survey (SDSS), and careful analyses of their optical spectra and precise measurement of spectral parameters. Combining them with our previous sample selected from SDSS DR4 makes it the largest LMBH sample so far, totaling over 500 objects. Some of the statistical properties of the combined LMBH AGN sample are briefly discussed in the context of exploring the low-mass end of the AGN population. Their X-ray luminosities follow the extension of the previously known correlation with the [O III] luminosity. The effective optical-to-X-ray spectral indices α OX, albeit with a large scatter, are broadly consistent with the extension of the relation with the near-UV luminosity L 2500 Å. Interestingly, a correlation of α OX with black hole mass is also found, with α OX being statistically flatter (stronger X-ray relative to optical) for lower black hole masses. Only 26 objects, mostly radio loud, were detected in radio at 20 cm in the FIRST survey, giving a radio-loud fraction of 4%. The host galaxies of LMBHs have stellar masses in the range of 108.8–1012.4 M ⊙ and optical colors typical of Sbc spirals. They are dominated by young stellar populations that seem to have undergone continuous star formation history.

  11. A COMPREHENSIVE X-RAY AND MULTIWAVELENGTH STUDY OF THE COLLIDING GALAXY PAIR NGC 2207/IC 2163

    Energy Technology Data Exchange (ETDEWEB)

    Mineo, S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street Cambridge, MA 02138 (United States); Rappaport, S. [37-602B, M.I.T. Department of Physics and Kavli Institute for Astrophysics and Space Research, 70 Vassar Street, Cambridge, MA 02139 (United States); Levine, A.; Homan, J. [M.I.T. Kavli Institute for Astrophysics and Space Research, Room 37-575, 70 Vassar Street, Cambridge, MA 02139 (United States); Pooley, D. [Eureka Scientific, Inc., 2452 Delmer Street, Suite 100, Oakland, CA 94602 (United States); Steinhorn, B., E-mail: smineo@cfa.harvard.edu, E-mail: sar@mit.edu, E-mail: aml@space.mit.edu, E-mail: jeroen@space.mit.edu, E-mail: dave@shsu.edu, E-mail: bsteinho@mit.edu [Harvard-MIT Division of Health Sciences and Technology, Harvard Medical School, 260 Longwood Avenue, Boston, MA 02115 (United States)

    2014-12-20

    We present a comprehensive study of the total X-ray emission from the colliding galaxy pair NGC 2207/IC 2163, based on Chandra, Spitzer, and GALEX data. We detect 28 ultraluminous X-ray sources (ULXs), 7 of which were not detected previously because of X-ray variability. Twelve sources show significant long-term variability, with no correlated spectral changes. Seven sources are transient candidates. One ULX coincides with an extremely blue star cluster (B – V = –0.7). We confirm that the global relation between the number and luminosity of ULXs and the integrated star-formation rate (SFR) of the host galaxy also holds on local scales. We investigate the effects of dust extinction and age on the X-ray binary (XRB) population on subgalactic scales. The distributions of N {sub X} and L {sub X} are peaked at L {sub IR}/L {sub NUV} ∼ 1, which may be associated with an age of ∼10 Myr for the underlying stellar population. We find that approximately one-third of the XRBs are located in close proximity to young star complexes. The luminosity function of the XRBs is consistent with that typical for high-mass XRBs and appears unaffected by variability. We disentangle and compare the X-ray diffuse spectrum with that of the bright XRBs. The hot interstellar medium dominates the diffuse X-ray emission at E ≲ 1 keV and has a temperature kT=0.28{sub −0.04}{sup +0.05} keV and intrinsic 0.5-2 keV luminosity of 7.9×10{sup 40} erg s{sup −1}, a factor of ∼2.3 higher than the average thermal luminosity produced per unit SFR in local star-forming galaxies. The total X-ray output of NGC 2207/IC 2163 is 1.5×10{sup 41} erg s{sup −1}, and the corresponding total integrated SFR is 23.7 M {sub ☉} yr{sup –1}.

  12. Modeling the Broad-Band Emission from the Gamma-Ray Emitting Narrow-Line Seyfert-1 Galaxies 1H 0323+342 and B2 0954+25A

    International Nuclear Information System (INIS)

    Arrieta-Lobo, Maialen; Boisson, Catherine; Zech, Andreas

    2017-01-01

    Prior to the Fermi-LAT era, only two classes of Active Galactic Nuclei (AGN) were thought to harbor relativistic jets that radiate up to gamma-ray energies: blazars and radio galaxies. The detection of variable gamma-ray emission from Narrow Line Seyfert 1 (NLSy1) galaxies has put them on the spotlight as a new class of gamma-ray emitting AGN. In this respect, gamma-ray emitting NLSy1s seem to be situated between blazars (dominated by non-thermal emission) and Seyferts (accretion disc dominated). In this work, we model the Spectral Energy Distribution (SED) of two gamma-loud NLSy1s, 1H 0323+342 and B2 0954+25A, during quiescent and flaring episodes via a multi-component radiative model that features a relativistic jet and external photon fields from the torus, disc, corona and Broad Line Region (BLR). We find that the interpretation of the high-energy emission of jetted NLSy1s requires taking into account Inverse Compton emission from particles in the relativistic jet that interact with external photon fields. Minimal changes are applied to the model parameters to transition from average to flaring states. In this scenario, the observed variability is explained mainly by means of changes in the jet density and Doppler factor.

  13. Modeling the Broad-Band Emission from the Gamma-Ray Emitting Narrow-Line Seyfert-1 Galaxies 1H 0323+342 and B2 0954+25A

    Energy Technology Data Exchange (ETDEWEB)

    Arrieta-Lobo, Maialen; Boisson, Catherine; Zech, Andreas, E-mail: maialen.arrieta@obspm.fr [Laboratoire Univers et Theories, Observatoire de Paris, CNRS, Université Paris-Diderot, PSL Research University, Meudon (France)

    2017-12-08

    Prior to the Fermi-LAT era, only two classes of Active Galactic Nuclei (AGN) were thought to harbor relativistic jets that radiate up to gamma-ray energies: blazars and radio galaxies. The detection of variable gamma-ray emission from Narrow Line Seyfert 1 (NLSy1) galaxies has put them on the spotlight as a new class of gamma-ray emitting AGN. In this respect, gamma-ray emitting NLSy1s seem to be situated between blazars (dominated by non-thermal emission) and Seyferts (accretion disc dominated). In this work, we model the Spectral Energy Distribution (SED) of two gamma-loud NLSy1s, 1H 0323+342 and B2 0954+25A, during quiescent and flaring episodes via a multi-component radiative model that features a relativistic jet and external photon fields from the torus, disc, corona and Broad Line Region (BLR). We find that the interpretation of the high-energy emission of jetted NLSy1s requires taking into account Inverse Compton emission from particles in the relativistic jet that interact with external photon fields. Minimal changes are applied to the model parameters to transition from average to flaring states. In this scenario, the observed variability is explained mainly by means of changes in the jet density and Doppler factor.

  14. THE RISE OF AN IONIZED WIND IN THE NARROW-LINE SEYFERT 1 GALAXY Mrk 335 OBSERVED BY XMM-NEWTON AND HST

    International Nuclear Information System (INIS)

    Longinotti, A. L.; Krongold, Y.; Kriss, G. A.; Ely, J.; Gallo, L.; Grupe, D.; Komossa, S.; Mathur, S.; Pradhan, A.

    2013-01-01

    We present the discovery of an outflowing ionized wind in the Seyfert 1 galaxy Mrk 335. Despite having been extensively observed by most of the largest X-ray observatories in the last decade, this bright source was not known to host warm absorber gas until recent XMM-Newton observations in combination with a long-term Swift monitoring program have shown extreme flux and spectral variability. High-resolution spectra obtained by the XMM-Newton Reflection Grating Spectrometer (RGS) detector reveal that the wind consists of three distinct ionization components, all outflowing at a velocity of ∼5000 km s –1 . This wind is clearly revealed when the source is observed at an intermediate flux state (2-5 × 10 –12 erg cm –2 s –1 ). The analysis of multi-epoch RGS spectra allowed us to compare the absorber properties at three very different flux states of the source. No correlation between the warm absorber variability and the X-ray flux has been determined. The two higher ionization components of the gas (log ξ ∼ 2.3 and 3.3) may be consistent with photoionization equilibrium, but we can exclude this for the only ionization component that is consistently present in all flux states (log ξ ∼ 1.8). We have included archival, non-simultaneous UV data from Hubble Space Telescope (FOS, STIS, COS) with the aim of searching for any signature of absorption in this source that so far was known for being absorption-free in the UV band. In the Cosmic Origins Spectrograph (COS) spectra obtained a few months after the X-ray observations, we found broad absorption in C IV lines intrinsic to the active galactic nucleus and blueshifted by a velocity roughly comparable to the X-ray outflow. The global behavior of the gas in both bands can be explained by variation of the covering factor and/or column density, possibly due to transverse motion of absorbing clouds moving out of the line of sight at broad line region scale.

  15. SPIRITS 15c and SPIRITS 14buu: Two Obscured Supernovae in the Nearby Star-forming Galaxy IC 2163

    International Nuclear Information System (INIS)

    Jencson, Jacob E.; Kasliwal, Mansi M.; Cao, Yi; Johansson, Joel; Contreras, Carlos; Castellón, Sergio; Morrell, Nidia; Phillips, Mark; Bond, Howard E.; Monson, Andrew J.; Masci, Frank J.; Helou, George; Cody, Ann Marie; Andrews, Jennifer E.; Bally, John; Green, Wayne; Fox, Ori D.; Gburek, Timothy; Gehrz, Robert D.; Hsiao, Eric

    2017-01-01

    SPitzer InfraRed Intensive Transients Survey—SPIRITS—is an ongoing survey of nearby galaxies searching for infrared (IR) transients with Spitzer /IRAC. We present the discovery and follow-up observations of one of our most luminous ( M [4.5] = −17.1 ± 0.4 mag, Vega) and reddest ([3.6] − [4.5] = 3.0 ± 0.2 mag) transients, SPIRITS 15c. The transient was detected in a dusty spiral arm of IC 2163 ( D ≈ 35.5 Mpc). Pre-discovery ground-based imaging revealed an associated, shorter-duration transient in the optical and near-IR (NIR). NIR spectroscopy showed a broad (≈8400 km s −1 ), double-peaked emission line of He i at 1.083 μ m, indicating an explosive origin. The NIR spectrum of SPIRITS 15c is similar to that of the Type IIb SN 2011dh at a phase of ≈200 days. Assuming an A V = 2.2 mag of extinction in SPIRITS 15c provides a good match between their optical light curves. The NIR light curves, however, show some minor discrepancies when compared with SN 2011dh, and the extreme [3.6]–[4.5] color has not been previously observed for any SN IIb. Another luminous ( M 4.5 = −16.1 ± 0.4 mag) event, SPIRITS 14buu, was serendipitously discovered in the same galaxy. The source displays an optical plateau lasting ≳80 days, and we suggest a scenario similar to the low-luminosity Type IIP SN 2005cs obscured by A V ≈ 1.5 mag. Other classes of IR-luminous transients can likely be ruled out in both cases. If both events are indeed SNe, this may suggest that ≳18% of nearby core-collapse SNe are missed by currently operating optical surveys.

  16. SPIRITS 15c and SPIRITS 14buu: Two Obscured Supernovae in the Nearby Star-forming Galaxy IC 2163

    Energy Technology Data Exchange (ETDEWEB)

    Jencson, Jacob E.; Kasliwal, Mansi M.; Cao, Yi [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Johansson, Joel [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Contreras, Carlos; Castellón, Sergio; Morrell, Nidia; Phillips, Mark [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Bond, Howard E.; Monson, Andrew J. [Dept. of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Masci, Frank J.; Helou, George [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Andrews, Jennifer E. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Bally, John; Green, Wayne [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Fox, Ori D. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Gburek, Timothy; Gehrz, Robert D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S. E., University of Minnesota, Minneapolis, MN 55455 (United States); Hsiao, Eric, E-mail: jj@astro.caltech.edu [Department of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL, 32306 (United States); and others

    2017-03-10

    SPitzer InfraRed Intensive Transients Survey—SPIRITS—is an ongoing survey of nearby galaxies searching for infrared (IR) transients with Spitzer /IRAC. We present the discovery and follow-up observations of one of our most luminous ( M {sub [4.5]} = −17.1 ± 0.4 mag, Vega) and reddest ([3.6] − [4.5] = 3.0 ± 0.2 mag) transients, SPIRITS 15c. The transient was detected in a dusty spiral arm of IC 2163 ( D ≈ 35.5 Mpc). Pre-discovery ground-based imaging revealed an associated, shorter-duration transient in the optical and near-IR (NIR). NIR spectroscopy showed a broad (≈8400 km s{sup −1}), double-peaked emission line of He i at 1.083 μ m, indicating an explosive origin. The NIR spectrum of SPIRITS 15c is similar to that of the Type IIb SN 2011dh at a phase of ≈200 days. Assuming an A {sub V} = 2.2 mag of extinction in SPIRITS 15c provides a good match between their optical light curves. The NIR light curves, however, show some minor discrepancies when compared with SN 2011dh, and the extreme [3.6]–[4.5] color has not been previously observed for any SN IIb. Another luminous ( M {sub 4.5} = −16.1 ± 0.4 mag) event, SPIRITS 14buu, was serendipitously discovered in the same galaxy. The source displays an optical plateau lasting ≳80 days, and we suggest a scenario similar to the low-luminosity Type IIP SN 2005cs obscured by A{sub V} ≈ 1.5 mag. Other classes of IR-luminous transients can likely be ruled out in both cases. If both events are indeed SNe, this may suggest that ≳18% of nearby core-collapse SNe are missed by currently operating optical surveys.

  17. RADIO VARIABILITY IN SEYFERT NUCLEI

    International Nuclear Information System (INIS)

    Mundell, C. G.; Ferruit, P.; Nagar, N.; Wilson, A. S.

    2009-01-01

    Comparison of 8.4 GHz radio images of a sample of eleven, early-type Seyfert galaxies with previous observations reveals possible variation in the nuclear radio flux density in five of them over a seven year period. Four Seyferts (NGC 2110, NGC 3081, MCG -6-30-15, and NGC 5273) show a decline in their 8.4 GHz nuclear flux density between 1992 and 1999, while one (NGC 4117) shows an increase; the flux densities of the remaining six Seyferts (Mrk 607, NGC 1386, Mrk 620, NGC 3516, NGC 4968, and NGC 7465) have remained constant over this period. New images of MCG -5-23-16 are also presented. We find no correlation between radio variability and nuclear radio luminosity or Seyfert nuclear type, although the sample is small and dominated by type 2 Seyferts. Instead, a possible correlation between the presence of nuclear radio variability and the absence of hundred parsec-scale radio emission is seen, with four out of five marginally resolved or unresolved nuclei showing a change in nuclear flux density, while five out of six extended sources show no nuclear variability despite having unresolved nuclear sources. NGC 2110 is the only source in our sample with significant extended radio structure and strong nuclear variability (∼38% decline in nuclear flux density over seven years). The observed nuclear flux variability indicates significant changes are likely to have occurred in the structure of the nucleus on scales smaller than the VLA beam size (i.e., within the central ∼0.''1 (15 pc)), between the two epochs, possibly due to the appearance and fading of new components or shocks in the jet, consistent with previous detection of subparsec-scale nuclear structure in this Seyfert. Our results suggest that all Seyferts may exhibit variation in their nuclear radio flux density at 8.4 GHz, but that variability is more easily recognized in compact sources in which emission from the variable nucleus is not diluted by unresolved, constant flux density radio jet emission

  18. Crashing galaxies, cosmic fireworks

    International Nuclear Information System (INIS)

    Keel, W.C.

    1989-01-01

    The study of binary systems is reviewed. The history of the study of interacting galaxies, the behavior of gas in binary systems, studies to identify the processes that occur when galaxies interact, and the relationship of Seyfert galaxies and quasars to binary systems are discussed. The development of an atlas of peculiar galaxies (Arp, 1966) and methods for modeling galaxy interactions are examined

  19. DEEP RADIO CONTINUUM IMAGING OF THE DWARF IRREGULAR GALAXY IC 10: TRACING STAR FORMATION AND MAGNETIC FIELDS

    International Nuclear Information System (INIS)

    Heesen, V.; Brinks, E.; Rau, U.; Rupen, M. P.; Hunter, D. A.

    2011-01-01

    We exploit the vastly increased sensitivity of the Expanded Very Large Array to study the radio continuum and polarization properties of the post-starburst, dwarf irregular galaxy IC 10 at 6 cm, at a linear resolution of ∼50 pc. We find close agreement between radio continuum and Hα emission, from the brightest H II regions to the weaker emission in the disk. A quantitative analysis shows a strictly linear correlation, where the thermal component contributes 50% to the total radio emission, the remainder being due to a non-thermal component with a surprisingly steep radio spectral index of between -0.7 and -1.0 suggesting substantial radiation losses of the cosmic-ray electrons. We confirm and clearly resolve polarized emission at the 10%-20% level associated with a non-thermal superbubble, where the ordered magnetic field is possibly enhanced due to the compression of the expanding bubble. A fraction of the cosmic-ray electrons has likely escaped because the measured radio emission is a factor of three lower than what is suggested by the Hα-inferred star formation rate.

  20. SN 2010ay IS A LUMINOUS AND BROAD-LINED TYPE Ic SUPERNOVA WITHIN A LOW-METALLICITY HOST GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, N. E.; Soderberg, A. M.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Valenti, S.; Smartt, S.; Botticella, M. T. [Astrophysics Research Centre, School of Maths and Physics, Queen' s University, Belfast BT7 1NN (United Kingdom); Hurley, K. [Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Barthelmy, S. D.; Gehrels, N.; Cline, T. [NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Levesque, E. M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Narayan, G. [Department of Physics, Harvard University, Cambridge, MA 02138 (United States); Briggs, M. S.; Connaughton, V. [CSPAR, University of Alabama in Huntsville, Huntsville, AL (United States); Terada, Y. [Department of Physics, Saitama University, Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama 338-8570 (Japan); Golenetskii, S.; Mazets, E., E-mail: nsanders@cfa.harvard.edu [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St. Petersburg 194021 (Russian Federation); and others

    2012-09-10

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3{pi} survey just {approx}4 days after explosion. The supernova (SN) had a peak luminosity, M{sub R} Almost-Equal-To -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v{sub Si} Almost-Equal-To 19 Multiplication-Sign 10{sup 3} km s{sup -1} at {approx}40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines {approx}2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of {sup 56}Ni, M{sub Ni} = 0.9 M{sub Sun }. Applying scaling relations to the light curve, we estimate a total ejecta mass, M{sub ej} Almost-Equal-To 4.7 M{sub Sun }, and total kinetic energy, E{sub K} Almost-Equal-To 11 Multiplication-Sign 10{sup 51} erg. The ratio of M{sub Ni} to M{sub ej} is {approx}2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H){sub PP04} + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and {approx}0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E{sub {gamma}} {approx}< 6 Multiplication-Sign 10{sup 48} erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E {approx}> 10{sup 48} erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less

  1. A close look at Seyfert 2 nuclei

    International Nuclear Information System (INIS)

    Fischer, Sebastian; Smajic, S; Valencia-S, M; Vitale, A; Zuther, J; Eckart, A

    2012-01-01

    We present SINFONI adaptive optics assisted and seeing limited NIR integral field spectroscopy of the central hundreds of pc of ten z < 0.01 Seyfert 2 galaxies. The main goal of this study is to assess the significance of star formation and extinction in the circumnuclear region of Seyfert 2s. The immediate surroundings of the nuclei are resolved at linear scales of about 50-100 parsecs for most of the observed sources. The intensity and line-of-sight velocity distribution of different species is derived from the 3D SINFONI data by calculating the higher order moments of the emission lines. As part of this work in progress, the resulting maps are currently analyzed following the approach of generalized surface photometry, which allows us to identify the multiple kinematical components in the circumnuclear region of Seyfert 2s.

  2. The ionizing radiation of Seyfert 2 galactic nuclei

    Science.gov (United States)

    Ho, Luis C.; Shields, Joseph C.; Filippenko, Alexei V.

    1993-01-01

    We report the discovery of a nonrandom trend in the dispersion of emission-line intensity ratios for Seyfert 2 galaxies. The sense of this pattern suggests the influence of a single physical parameter, the hardness of the ionizing continuum, which controls the heating energy per ionizing photon. We compare the observed line ratios with new photoionization calculations and find that the observed distributions can be reproduced if the ionizing continuum is parametrized by a power law. Our results also suggest an inverse correlation between luminosity and continuum hardness for Seyfert 2 nuclei; if true, this trend extends a similar pattern known in quasars and Seyfert 1 galaxies to active galactic nuclei of lower luminosity. Samples of Seyfert 2 nuclei with improved selection uniformity are desirable for elaboration of these findings.

  3. The broad-band X-ray spectrum of IC 4329A from a joint NuSTAR/Suzaku observation

    DEFF Research Database (Denmark)

    Brenneman, L. W.; Madejski, G.; Fuerst, F.

    2014-01-01

    We have obtained a deep, simultaneous observation of the bright, nearby Seyfert galaxy IC 4329A with Suzaku andNuSTAR. Through a detailed spectral analysis, we are able to robustly separate the continuum, absorption, and distant reflection components in the spectrum. The absorbing column is found...... also updated our previously reported measurement of the high-energy cutoff of the hard X-ray emission using both observatories rather than justNuSTAR alone: Ecut = 186±14 keV. This high-energy cutoff acts as a proxy for the temperature of the coronal electron plasma, enabling us to further separate...

  4. Was the Narrow Line Seyfert 1 RGB J0044+193 ever radio loud?

    NARCIS (Netherlands)

    Maccarone, T.J.; Miller-Jones, J.C.A.; Fender, R.P.; Pooley, G.G.

    2005-01-01

    We show new radio data and a re-analysis of old data for the Narrow Line Seyfert 1 (NLSy1) galaxy RGB J0044+193. This galaxy has previously been suggested to be both radio loud, and highly variable in the radio. As most NLSy 1 galaxies are radio quiet, this was interpreted as possible evidence that

  5. Transformation of a Virgo Cluster Dwarf Irregular Galaxy by Ram Pressure Stripping: IC3418 and Its Fireballs

    Czech Academy of Sciences Publication Activity Database

    Kenney, J.D.P.; Geha, M.; Jáchym, Pavel; Crowl, H.H.; Dague, W.; Chung, A.; van Gorkom, J.; Vollmer, B.

    2014-01-01

    Roč. 780, č. 2 (2014), 119/1-119/20 ISSN 0004-637X Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100031203 Program:M Institutional support: RVO:67985815 Keywords : galaxies * cluster * evolution Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.993, year: 2014

  6. Search for very high energy gamma-ray emission from the peculiar radio galaxy IC 310 with TACTIC during 2012 to 2015

    Science.gov (United States)

    Ghosal, B.; Singh, K. K.; Yadav, K. K.; Tickoo, A. K.; Rannot, R. C.; Chandra, P.; Kothari, M.; Gaur, K. K.; Goyal, H. C.; Goyal, A.; Kumar, N.; Marandi, P.; Chanchalani, K.; Agarwal, N. K.; Dhar, V. K.; Koul, M. K.; Koul, R.; Venugopal, K.; Bhat, C. K.; Chouhan, N.; Borwankar, C.; Kaul, S. R.; Bhatt, H.; Agarwal, A.; Gupta, A. C.

    2018-04-01

    Non-blazar active galactic nuclei like radio galaxies have emerged as a new class of γ-ray sources in the sky. Observations of very high energy (VHE) γ-rays from radio galaxies with misaligned jets offer a unique tool to understand the physical processes involved in these type of objects. In this work, we present the results of our observations of the nearby peculiar radio galaxy IC 310 (z = 0.0189) with TACTIC telescope for nearly 95.5 hours from 03 December, 2012 to 19 January, 2015 (MJD 56265 - 57041). Detailed analysis of the data reveals absence of a statistically significant γ-ray signal from the source direction (both on the overall period and on yearly basis). Our results suggest that the source was possibly in a low-TeV emission state (below the TACTIC sensitivity level) during the above mentioned observation period and the resulting 3σ upper limit on the integral flux above 850 GeV has been estimated to be 4.99 ×10-12phcm-2s-1 (23% of the Crab Nebula flux). Analysis of the contemporaneous data collected by Fermi-LAT in the 30 - 300 GeV energy range, also indicate the absence of a statistically significant γ-ray signal, therefore 2σ upper limit on the integral flux above 30 GeV has been estimated on yearly basis. We also report the results from dedicated optical observations in B, V and R bands from ARIES observatory carried out from December, 2014 to March, 2015.

  7. INTEGRAL observations of the GeV blazar PKS 1502+106 and the hard X-ray bright Seyfert galaxy Mkn 841

    Czech Academy of Sciences Publication Activity Database

    Pian, E.; Ubertini, P.; Bazzano, A.; Beckmann, V.; Eckert, D.; Ghisellini, G.; Pursimo, T.; Tagliaferri, G.; Tavecchio, F.; Türler, M.; Bianchi, S.; Bianchin, V.; Hudec, René; Maraschi, L.; Raiteri, C.M.; Soldi, S.; Treves, A.; Villata, M.

    2011-01-01

    Roč. 526, February (2011), A125/1-A125/7 ISSN 0004-6361 Grant - others:ESA(XE) ESA PECS project No.98023; GA ČR(CZ) ga102/09/0997 Institutional research plan: CEZ:AV0Z10030501 Keywords : active galaxies * blazar PKS 1502+106 Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

  8. Emission Line Galaxies Behind the Planetary Nebula IC 5148: Potential for a Serendipity Survey with Archival Data

    Science.gov (United States)

    Kimeswenger, S.; Barria, D.; Kausch, W.; Goldman, D. S.

    2018-04-01

    During the start of a survey program using FORS2 long slit spectroscopy on planetary nebulae (PN) and their haloes, we serendipitously discovered six background emission line galaxies (ELG) with redshifts of z = 0.2057, 0.3137, 0.37281, 0.4939, 0.7424 and 0.8668. Thus they clearly do not belong to a common cluster structure. We derived the major physical properties of the targets. Since the used long slit covers a sky area of only 570 arcsec2 (= 4.3×10-5 square degrees), we discuss further potential of serendipitous discoveries in archival data, beside the deep systematic work of the ongoing and upcoming big surveys. We conclude that archival data provide a decent potential for extending the overall data on ELGs without any selection bias.

  9. FHILs in Seyferts and Liners in the optical spectra

    Science.gov (United States)

    Vera, R. J. C.; Rodriguez, A. M.; Portilla, J. G.

    2014-10-01

    We present the main results from a selection of optical spectra of Seyfert and LINER galaxies taken from the 9^{th} release of the SDSS with detectable emission of forbidden high ionization lines (FHILs), better known as coronal lines. A catalog of 345 Seyfert 1 (Sy1) and Seyfert 2 (Sy2) galaxies with FHILs emission is presented. By analyzing their spectra and utilizing data from the literature we found the following results: (1) The flux ratios between FHILs suggests anisotropy of emission between Sy1 and Sy2 galaxies, which agrees with the results found by Nagao et al. (2002) and Portilla (2012). Sy1 seems to emit more FHILs than Sy2. (2) This anisotropy suggests the idea that an important, but not the majority, of the emission of FHILs comes from the inner part of the obscuring torus. (3) We present diagnostic diagrams between FHILs lines which indicate clear correlations between the flux ratios. (4) It is observed that the ratio of Ne V/Fe VII is of the order of 3 to 10, while the ratios between iron lines (i.e., Fe VII, Fe X, Fe XI) are roughly around the unity. (5) At least in the optical spectra, the present study continues to support the general idea that LINERs are not energetic enough to present FHILs. A complete version of this study including the catalog with the objects of study, and diagnosis diagrams using only this kind of lines can be found in Vera & Portilla (in prep).

  10. Simultaneous NuSTAR and XMM-Newton 0.5-80 keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654

    DEFF Research Database (Denmark)

    Marinucci, A.; Matt, G.; Kara, E.

    2014-01-01

    We present a broad-band spectral analysis of the joint XMM-Newton and Nuclear Spectroscopic Telescope Array observational campaign of the narrow-line Seyfert 1 SWIFT J2127.4+5654, consisting of 300 ks performed during three XMM-Newton orbits. We detect a relativistic broadened iron Kα line...

  11. H{sub 2}O Megamasers toward Radio-bright Seyfert 2 Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J. S.; Liu, Z. W. [Center for Astrophysics, Guangzhou University, Guangzhou, 510006 (China); Henkel, C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Wang, J. Z. [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Coldwell, G. V., E-mail: jszhang@gzhu.edu.cn [FCEFyN-UNSJ-CONICET, San Juan (Argentina)

    2017-02-20

    Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H{sub 2}O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 ( z ∼ 0.0448), was detected four times during our observations, with a typical maser flux density of ∼30 mJy and a corresponding (very large) luminosity of ∼1135 L {sub ⊙}. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H{sub 2}O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H{sub 2}O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies.

  12. H2O Megamasers toward Radio-bright Seyfert 2 Nuclei

    Science.gov (United States)

    Zhang, J. S.; Liu, Z. W.; Henkel, C.; Wang, J. Z.; Coldwell, G. V.

    2017-02-01

    Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H2O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 (z ˜ 0.0448), was detected four times during our observations, with a typical maser flux density of ˜30 mJy and a corresponding (very large) luminosity of ˜1135 L ⊙. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H2O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H2O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies. Based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg.

  13. Central structures of Seyfert galaxy NGC 1672

    Science.gov (United States)

    Firpo, V.; Díaz, R.; Dottori, H.; Aguero, M. P.; Bosch, G.; Hagele, G.; Cardaci, M.; Dors, O.

    2017-10-01

    We present the velocity field of the inner 4"(350 pc) of NGC1672, observed with Gemini GMOS/IFU with a spatial sampling of 0.2", spatial resolution of 0.4", and spectral resolution 6000. We determine an upper limit for the mass of the SMBH in the LINER core using the ionized gas radial velocity field, and we confirmed that the active galactic nucleus is located off-center respect to the circumnuclear disk rotation symmetry center.

  14. A High-definition View Of The Circum-nuclear Regions In Nearby Seyferts With Chandra And HST

    Science.gov (United States)

    Wang, Junfeng; Fabbiano, G.; Elvis, M.; Risaliti, G.; Karovska, M.; Zezas, A.; Mundell, C. G.

    2011-09-01

    To improve our understanding of AGN feedback, it is crucial to evaluate the true role of outflows on galaxy evolution observationally. I will present new results from the CHandra survey of Extended Emission-line Regions in nearby Seyfert galaxies (CHEERS), which aims to examine feedback in action in much greater detail than at high redshift. Findings from Chandra studies of the circum-nuclear region in the archetypal Seyfert 1 galaxy NGC 4151 will be discussed in detail. Exploiting Chandra's highest possible resolution, we find evidence for X-ray emission from interaction between radio outflow and the optical narrow-line region clouds, in addition to the emission from photoionized gas.

  15. A molecular line survey toward the nearby galaxies NGC 1068, NGC 253, and IC 342 at 3 mm with the Nobeyama 45 m radio telescope: Impact of an AGN on 1 kpc scale molecular abundances

    Science.gov (United States)

    Nakajima, Taku; Takano, Shuro; Kohno, Kotaro; Harada, Nanase; Herbst, Eric

    2018-01-01

    It is important to investigate the relationships between the power sources and the chemical compositions of galaxies in order to understand the scenario of galaxy evolution. We carried out an unbiased molecular line survey towards active galactic nucleus (AGN) host galaxy NGC1068, and prototypical starburst galaxies, NGC 253 and IC 342, with the Nobeyama 45 m telescope in the 3 mm band. The advantage of this line survey is that the obtained spectra have the highest angular resolution ever obtained with single-dish telescopes. In particular, the beam size of this telescope is ˜15″-19″, which is able to separate spatially the nuclear molecular emission from that of the starburst ring (d ˜ 30″) in NGC 1068. We successfully detected approximately 23 molecular species in each galaxy, and calculated rotation temperatures and column densities. We estimate the molecular fractional abundances with respect to 13CO and CS molecules and compare them among three galaxies in order to investigate the chemical signatures of an AGN environment. As a result, we found clear trends in the abundances of molecules surrounding the AGN on a 1-kpc scale. HCN, H13CN, CN, 13CN, and HC3N are more abundant, and CH3CCH is deficient in NGC 1068 compared with the starburst galaxies. High abundances of HCN, H13CN, and HC3N suggest that the circumnuclear disk in NGC 1068 is in a high-temperature environment. The reason for the non-detection of CH3CCH is likely to be dissociation by high-energy radiation or less sublimation of a precursor of CH3CCH from grains.

  16. Submillimeter Array/Plateau de Bure Interferometer Multiple Line Observations of the Nearby Seyfert 2 Galaxy NGC 1068: Shock-related Gas Kinematics and Heating in the Central 100 pc?

    Czech Academy of Sciences Publication Activity Database

    Krips, M.; Martin, S.; Eckart, A.; Neri, R.; Garcia-Burillo, S.; Matsushita, S.; Peck, A.; Stoklasová, Ivana; Petitpas, G.; Usero, A.; Combes, F.; Schinnerer, E.; Humphreys, L.; Baker, A.

    2011-01-01

    Roč. 736, 1-4 (2011), 37/1-37/27 ISSN 0004-637X R&D Projects: GA MŠk(CZ) LC06014 Institutional research plan: CEZ:AV0Z10030501 Keywords : galaxies * active galaxies * NGC 1068 Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.024, year: 2011

  17. Which observational differences are still left between Seyfert 1 and Seyfert 2 nuclei?

    CERN Document Server

    Alloin, D

    1979-01-01

    Reviews the different observational properties used, up to now, to discriminate between Seyfert 1 and Seyfert 2: emission lines widths, Fe II lines, intensity ration (OIII) 500.7 nm/H beta , radio, infrared, visible, UV and X-emission. Most of these parameters exhibit a more or less continuous distribution from the less powerful Seyfert 2 up to the Seyfert 1 nuclei (except in the radio range). (0 refs).

  18. A long XMM-Newton observation of an extreme narrow-line Seyfert 1: PG 1244+026

    NARCIS (Netherlands)

    Jin, C.; Done, C.; Middleton, M.; Ward, M.

    2013-01-01

    We explore the origin of the strong soft X-ray excess in narrow-line Seyfert 1 galaxies using spectral-timing information from a 120 ks XMM-Newton observation of PG 1244+026. Spectral fitting alone cannot distinguish between a true additional soft X-ray continuum component and strongly

  19. The AGN Population in Nearby Galaxies

    International Nuclear Information System (INIS)

    Filho, Mercedes; Barthel, Peter; Ho, Luis

    2006-01-01

    In order to determine the incidence of black hole accretion-driven nuclear activity in nearby galaxies, we have compiled radio data for the LINERs, composite LINER,/Hn and Seyfert galaxies from a complete magnitude-limited sample of bright nearby galaxies (Palomar sample). Our results show an overall radio detection rate of 54% (22% of all bright nearby galaxies) and we estimate that at least ∼50% (∼20% of all bright nearby galaxies) are true AGN. By comparing the radio luminosity function of the LINERs, composite LINER/Hll and Seyferts galaxies in the Palomar sample with those of selected moderate-redshift AGN, we fhd that our sources naturally extend the radio luminosity function of powerful AGN down to powers of about 10 times that of Sgr A*

  20. Atomic hydrogen properties of active galactic nuclei host galaxies: H I in 16 nuclei of galaxies (NUGA) sources

    International Nuclear Information System (INIS)

    Haan, Sebastian; Schinnerer, Eva; Mundell, Carole G.; García-Burillo, Santiago; Combes, Francoise

    2008-01-01

    We present a comprehensive spectroscopic imaging survey of the distribution and kinematics of atomic hydrogen (H I) in 16 nearby spiral galaxies hosting low luminosity active galactic nuclei (AGN), observed with high spectral and spatial resolution (resolution: ∼20'', ∼5 km s –1 ) using the NRAO Very Large Array (VLA). The sample contains a range of nuclear types ranging from Seyfert to star-forming nuclei, and was originally selected for the NUclei of GAlaxies project (NUGA)—a spectrally and spatially resolved interferometric survey of gas dynamics in nearby galaxies designed to identify the fueling mechanisms of AGN and the relation to host galaxy evolution. Here we investigate the relationship between the H I properties of these galaxies, their environment, their stellar distribution, and their AGN type. The large-scale H I morphology of each galaxy is classified as ringed, spiral, or centrally concentrated; comparison of the resulting morphological classification with the AGN type reveals that ring structures are significantly more common in low-ionization narrow emission-line regions (LINER) than in Seyfert host galaxies, suggesting a time evolution of the AGN activity together with the redistribution of the neutral gas. Dynamically disturbed H I disks are also more prevalent in LINER host galaxies than in Seyfert host galaxies. While several galaxies are surrounded by companions (some with associated H I emission), there is no correlation between the presence of companions and the AGN type (Seyfert/LINER).

  1. Star formation in active galaxies and quasars

    International Nuclear Information System (INIS)

    Heckman, T.M.

    1987-01-01

    I review the observational evidence for a causal or statistical link between star formation and active galactic nuclei. The chief difficulty is in quantitatively ascertaining the star formation rate in active galaxies: most of the readily observable manifestations of star formation superficially resemble those of an active nucleus. Careful multi-wavelength spatially-resolved observations demonstrate that many Seyfert galaxies are undergoing star formation. Our survey of CO emission from Seyferts (interpreted in conjunction IRAS data) suggests that type 2 Seyferts have unusually high rates of star formation, but type 1 Seyferts do not. Recent work also suggests that many powerful radio galaxies may be actively forming stars: radio galaxies with strong emission-lines often have blue colors and strong far-infrared emission. Determining the star formation rate in the host galaxies of quasars is especially difficult. Multi-color imaging and long-slit spectroscopy suggests that many of the host galaxies of radio-loud quasars are blue and a cold interstellar medium has been detected in some quasar hosts

  2. IC 3639 - A new bona fide Compton thick AGN unveiled by NuSTAR

    DEFF Research Database (Denmark)

    Boorman, Peter G.; Gandhi, P.; Alexander, D.

    2016-01-01

    We analyse high-quality NuSTAR observations of the local (z = 0.011) Seyfert 2 active galactic nucleus (AGN) IC 3639, in conjunction with archival Suzaku and Chandra data. This provides the first broadband X-ray spectral analysis of the source, spanning nearly two decades in energy (0.5 -30 keV)....

  3. Imaging Spectrophotometry of the Jet/ISM Interaction in IC5063

    Science.gov (United States)

    Cecil, G.; Schuft, B.; Morse, J.; Bland-Hawthorn, J.

    2004-01-01

    IC5063 is a somewhat dusty z=0.0110 S0 galaxy with a Seyfert 2 nucleus. It has a triple radio source that spans 3 arcsec, mostly blueshifted H I absorption that spans 700 km/s, and ionization cones that extend for more than 2 arcmins. We obtained fully sampled [O III]\\lambda5007 grids at 0."9 and 70 km/s FWHM resolution using the Rutgers Fabry-Perot system on the Blanco 4m telescope. Complementary long-slit spectra using the RC spectrograph on the Blanco, and Taurus Tunable Filter spectral images in H\\alpha and [N II]\\lambda6583, were also obtained to assess gaseous ionization conditions. We present the results of our analysis, and correlate spectral structures to those visible in archival WFPC2 images. We find that, in the region near the radio triple, gaseous ionization and line velocity width is tightly correlated, in excellent quantitative agreement with the high-velocity shock regime in the diagnostic emission-line ratio diagrams of Dopita & Sutherland. We separate kinematically gas in normal disk rotation that is illuminated by the AGN in the ionization cones from that agitated mechanically by the jet, and assess the energy input from both processes.

  4. Measuring the coronal properties of IC 4329A with NuSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Brenneman, L. W.; Elvis, M. [Harvard-Smithsonian CfA, 60 Garden Street MS-67, Cambridge, MA 02138 (United States); Madejski, G. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Fuerst, F.; Harrison, F. A.; Grefenstette, B. W.; Madsen, K. K.; Rivers, E.; Walton, D. J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Matt, G.; Marinucci, A. [Dipartimento di Matematica e Fisica, Università Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Ballantyne, D. R. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Boggs, S. E. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E.; Craig, W. W. [DTU Space National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, W. W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-02-01

    We present an analysis of a ∼160 ks NuSTAR observation of the nearby bright Seyfert galaxy IC 4329A. The high-quality broadband spectrum enables us to separate the effects of distant reflection from the direct coronal continuum, and to therefore accurately measure the high-energy cutoff to be E{sub cut}=178{sub −40}{sup +74} keV. The coronal emission arises from accretion disk photons Compton up-scattered by a thermal plasma, with the spectral index and cutoff being due to a combination of the finite plasma temperature and optical depth. Applying standard Comptonization models, we measure both physical properties independently using the best signal to noise obtained to date in an active galactic nucleus over the 3-79 keV band. We derive kT{sub e}=37{sub −6}{sup +7} keV with τ=1.25{sub −0.10}{sup +0.20} assuming a slab geometry for the plasma, and kT{sub e}=33{sub −6}{sup +6} keV with τ=3.41{sub −0.38}{sup +0.58} for a spherical geometry, with both having an equivalent goodness-of-fit.

  5. Measuring the coronal properties of IC 4329A with NuSTAR

    DEFF Research Database (Denmark)

    Brenneman, L. W.; Madejski, G.; Fuerst, F.

    2014-01-01

    We present an analysis of a ~160 ks NuSTAR observation of the nearby bright Seyfert galaxy IC 4329A. The highquality broadband spectrum enables us to separate the effects of distant reflection from the direct coronal continuum, and to therefore accurately measure the high-energy cutoff to be Ecut...... = 178-40+74 keV. The coronal emission arises from accretion disk photons Compton up-scattered by a thermal plasma, with the spectral index and cutoff being due to a combination of the finite plasma temperature and optical depth. Applying standard Comptonization models, we measure both physical...... properties independently using the best signal to noise obtained to date in an active galactic nucleus over the 3-79 keV band. We derive kTe = 37-6+7 keV with τ = 1.25-0.10+0.20 assuming a slab geometry for the plasma, and kTe = 33-6+6 keV with τ = 3.41-0.38+0.58 for a spherical geometry, with both having...

  6. On the relationship between optical and radio emission from active galaxy nuclei

    International Nuclear Information System (INIS)

    Zentsova, A.S.; Fedorenko, V.N.

    1991-01-01

    Model in which the radio emission of nuclei of Seyfert galaxies emerges in the regions of formation of their narrow emission lines, R∼100 pc is developed. Gaseous clouds, producing this emission, are moving in the surrounding hot gas and induce shock waves. The shock waves accelerate electrons, which produce radio emission via synchrotron mechanism. The model explains an observational correlation between the radio and optical properties of Seyfert galaxies and makes some predictions on the parameters of the region R∼100 pc

  7. The Phoenix galaxy as seen by NuSTAR

    DEFF Research Database (Denmark)

    Masini, A.; Comastri, A.; Puccetti, S.

    2017-01-01

    Aims. We study the long-term variability of the well-known Seyfert 2 galaxy Mrk 1210 (also known as UGC 4203, or the Phoenix galaxy). Methods. The source was observed by many X-ray facilities in the last 20 yr. Here we present a NuSTAR observation and put the results in the context of previously ...

  8. 150 southern compact and bright-nucleus galaxies

    International Nuclear Information System (INIS)

    Fairall, A.P.

    1977-01-01

    Galaxies having regions of exceptionally high surface brightness have been selected from the ESO Quick Blue Survey and investigated by 'grating photography' -direct photography plus low-dispersion slitless spectroscopy. Two new Seyfert galaxies and a peculiar multiple system have been discovered. Differences in red continua are also noted. (author)

  9. Integral Field Spectroscopy of Markarian 273: Mapping High-Velocity Gas Flows and an Off-Nucleus Seyfert 2 Nebula.

    Science.gov (United States)

    Colina; Arribas; Borne

    1999-12-10

    Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies.

  10. The environments of Markarian galaxies

    International Nuclear Information System (INIS)

    Mackenty, J.W.; Simpson, C.; Mclean, B.

    1990-01-01

    The extensively studied Markarian sample of 1500 ultraviolet excess galaxies contains many Seyfert, starburst, and peculiar galaxies. Using the 20 minute V plates obtained for the construction of the Hubble Space Telescope Guide Star Catalog, the authors investigated the morphologies of the Markarian galaxies and the environments in which they are located. The relationship between the types of nuclear activity and the morphologies and environments of the Markarian galaxies is discussed. The authors conclude that the type of nuclear activity present in the galaxies of the Markarian sample is not dependent on either the morphology or the local environment of the galaxy. This is not to imply that nuclear activity per se is not influenced by the environment in which the nucleus is located. Rather the type of nuclear activity (at least in the Markarian population) does not appear to be determined by the environment

  11. Men and IC

    Science.gov (United States)

    ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ...

  12. IC Treatment: Surgical Procedures

    Science.gov (United States)

    ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ...

  13. IC: Frequently Asked Questions

    Science.gov (United States)

    ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ...

  14. General IC Symptoms

    Science.gov (United States)

    ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ...

  15. Children and IC

    Science.gov (United States)

    ... Cola, and Orange Crush, for example), Kool-Aid, chocolate, and many fruits, fruit juices and drinks (including ... Guideline IC Treatments IC Diet & Self Management Physical Therapy Antidepressants Antihistamines Pentosan Polysulfate Sodium Bladder Instillations Immunosuppresants ...

  16. Galaxies and gamma-ray astronomy

    International Nuclear Information System (INIS)

    Bignami, G.F.; Fichtel, C.E.; Hartman, R.C.; Thompson, D.J.

    1979-01-01

    Comparisons between the recently measured X-ray spectra of active galaxies, the intensity upper limits to the γ-ray emission above 35 MeV from the same objects obtained from data from SAS 2, and other γ-ray data are used to address the nature of the high-energy spectra of several types of active galaxies, their contribution to the measured diffuse γ-ray emission between 1 and 150 MeV, and constraints which may be placed on cosmological evolutionary factors. It is found that a substantial increase in slope of the photon energy spectrum must occur in the low-energy γ-ray region for Seyfert galaxies, BL Lac objects, and emission line galaxies. A spectral steepening is also seen for 3C 273 and Cen A, the only quasar and radio galaxy for which accurate X-ray spectra are presently available above 20 keV. A cosmological integration shows that Seyfert galaxies, BL Lac objects, and quasars may account for most of the 1--150 MeV diffuse background, even without significant evolution. Sharp emission line galaxies and radio galaxies made a much smaller contribution under the same assumptions. The observed isotropic γ-radiation limits the γ-ray evolution possible for Seyfert galaxies, BL Lac objects, and quasars. The high-latitude galactic radiation limits the γ-ray evolution of normal field galaxies. The integrated emission of normal field galaxies with evolution back to z=4 cannot exceed about 10 times the integrated emission assuming no evolution

  17. Spitzer Observations Of IC 2118

    Science.gov (United States)

    2010-09-01

    Micron All-Sky Survey ( 2MASS ; Skrutskie et al. 2006) photometric data in an effort to segregate YSOs from background galaxies. While one previously known T...Spectral Typea Other names IRAS 04591−0856 05 01 30.2 −08 52 14 . . . HHL 17, G13 2MASS 05020630−0850467 05 02 06.3 −08 50 47 M2 IV . . . RXJ 0502.4−0744b...05 02 20.8 −07 44 10 . . . 2MASS 05022084−0744099 2MASS 05060574−0646151c 05 06 05.7 −06 46 15 G8: (May not be a member of IC 2118; see Kun et al

  18. Pregnancy and IC

    Science.gov (United States)

    ... have not already done so, try to identify foods, beverages, and supplements that are irritating to your bladder ... Other Medicines Over-the-counter Medicines Pain Management Management of IC ... Diet Food Diaries Least and Most Bothersome Foods IC-Friendly ...

  19. Extreme warm absorber variability in the Seyfert galaxy Mrk 704

    Czech Academy of Sciences Publication Activity Database

    Matt, G.; Bianchi, S.; Guainazzi, M.; Longinotti, A. L.; Dadina, M.; Karas, Vladimír; Malaguti, G.; Miniutti, G.; Petrucci, P. O.; Piconcelli, E.; Ponti, G.

    Roč. 533, September (2011), A1/1-A1/9 ISSN 0004-6361 Institutional research plan: CEZ:AV0Z10030501 Keywords : active galactic nuclei Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

  20. The ultraviolet spectrum of the Seyfert galaxy NGC 4151

    International Nuclear Information System (INIS)

    Boksenberg, A.; Penston, M.V.

    1976-01-01

    Spectra at 1.3 A resolution of the spectral region lambda lambda 3100 to 4000 have been obtained. Identifications and equivalent widths of emission lines are presented. The He I lambda 3889 absorption varied by a factor 3.5 in 37 days and He I lambda 3188 absorption was seen when lambda 3889 was strong. The [N I] line ratio lambda 5199 to 3466 is consistent with nsub(e) approximately 10 4 cm -2 in the region emitting the forbidden lines. Several short-wavelength lines are identified including the He II lambda 3203 and several lines of [Fe V] multiplet 3F. (author)

  1. The Broadband XMM-Newton and NuSTAR X-ray Spectra of Two Ultraluminous X-ray Sources in the Galaxy IC 342

    DEFF Research Database (Denmark)

    Rana, Vikram; Harrison, Fiona A.; Bachetti, Matteo

    2015-01-01

    We present results for two Ultraluminous X-ray Sources (ULXs), IC 342 X-1 and IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by ∼7 days. We observe little spectral or flux variability above 1 keV between epochs, with unabsorbed 0.3-30 keV luminosities being $1.04+0.0...

  2. New radio observations of the Circinus Galaxy

    International Nuclear Information System (INIS)

    Harnett, J.I.; Reynolds, J.E.

    1990-01-01

    We present new radio continuum and OH observations of the Circinus Galaxy which confirm the active nature of the nucleus. The continuum structure is dominated by two spurs of emission, which probably originate in the core and extend roughly along the minor axis of the galaxy. In addition, the OH absorption profiles clearly indicate a rapidly rotating cloud surrounding the nucleus or several independent clouds in the vicinity with inflowing and outflowing motions. The Circinus Galaxy is most probably a Seyfert with underlying nuclear starburst activity. (author)

  3. IC Associated Conditions

    Science.gov (United States)

    ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Newly Diagnosed Toolkit IC Awareness Toolkit Know ... Bowel Syndrome Lupus Pelvic Floor Dysfunction Pudendal Neuralgia Sjogren’s Syndrome Vulvodynia Click to learn more about these and ...

  4. Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra

    Science.gov (United States)

    Thompson, Grant D.; Levenson, N. A.; Sirocky, M. M.; Uddin, S.

    2007-12-01

    Silicate dust emission dominates the mid-infrared spectra of galaxies, and the dust produces two spectral features, at 10 and 18 μm. These features' strengths (in emission or absorption) and peak wavelengths reveal the geometry of the dust distribution, and they are sensitive to the dust composition. We examine mid-infrared spectra of 32 Seyfert 1 active galactic nuclei (AGN), observed with the Infrared Spectrograph aboard the Spitzer Space Telescope. In the spectra, we typically find the shorter-wavelength feature in emission, at an average peak wavelength of 10.0 μm, although it is known historically as the "9.7 μm" feature. In addition, peak wavelength increases with feature strength. The 10 and 18 μm feature strengths together are sensitive to the dust geometry surrounding the central heating engine. Numerical calculations of radiative transfer distinguish between clumpy and smooth distributions, and we find that the surroundings of these AGN (the obscuring "tori" of unified AGN schemes) are clumpy. Polycyclic aromatic hydrocarbon (PAH) features are associated with star formation, and we find strong PAH emission (luminosity ≥ 1042 erg/s) in only four sources, three of which show independent evidence for starbursts. We will explore the effects of luminosity on dust geometry and chemistry in a comparison sample of quasars. We acknowledge work supported by the NSF under grant number 0237291.

  5. LD to IC

    CERN Multimedia

    Association du personnel

    2010-01-01

    LC to IC – Publication of posts: Following the publication of new LD to IC posts, we regret that a large number of post descriptions are not available in both CERN official languages, English and French. Consequently, the Staff Association has decided to provide assistance to those who need it with the translation of one or more posts of interest. To do this, please contact the Staff Association secretariat, tel. 72819 or 72761 or 74224.

  6. The Search for Wolf-Rayet Stars in IC10

    Science.gov (United States)

    Tehrani, Katie; Crowther, Paul; Archer, Isabelle

    2017-11-01

    We present a deep imaging and spectroscopic survey of the Local Group starburst galaxy IC10 using Gemini North/GMOS to unveil the global Wolf-Rayet population. It has previously been suggested that for IC10 to follow the WC/WN versus metallicity dependence seen in other Local Group galaxies, a large WN population must remain undiscovered. Our search revealed 3 new WN stars, and 5 candidates awaiting confirmation, providing little evidence to support this claim. We also compute an updated nebular derived metallicity of log(O/H)+12=8.40 +/- 0.04 for the galaxy using the direct method. Inspection of IC10 WR average line luminosities show these stars are more similar to their LMC, rather than SMC counterparts.

  7. Recent star formation in interacting galaxies

    International Nuclear Information System (INIS)

    Joseph, R.D.; Wright, G.S.

    1985-01-01

    The subset of galaxy-galaxy interactions which have resulted in a merger are, as a class, ultraluminous IR galaxies. Their IR luminosities span a narrow range which overlaps with the most luminous Seyfert galaxies. However, in contrast with Seyfert galaxies, the available optical, IR, and radio properties of mergers show no evidence for a compact non-thermal central source, and are easily understood in terms of a burst of star formation of extraordinary intensity and spatial extent; they are 'super starbursts'. We argue that super starbursts occur in the evolution of most mergers, and discuss the implications of super starbursts for the suggestion that mergers evolve into elliptical galaxies. Finally, we note that merger-induced shocks are likely to leave the gas from both galaxies in dense molecular form which will rapidly cool, collapse, and fragment. Thus a merger might in fact be expected to result in a burst of star formation of exceptional intensity and spatial extent, i.e. a super starburst. (author)

  8. The H II regions of IC 1613

    International Nuclear Information System (INIS)

    Hodge, P.; Lee, M.G.; Gurwell, M.

    1990-01-01

    Narrow-band CCD H-alpha imaging of the Local Group irregular galaxy IC 1613 has revealed a total of 77 H II regions, five of which are complexes of several smaller emission regions. Positions, H-alpha luminosities, and sizes of these objects are tabulated. The H-alpha luminosity function has the same shape as that for more luminous galaxies, following a power law with an exponent of -1.6. The faintest H II regions are at the low-luminosity end of the generally observed luminosity function for H II regions in galaxies, with fluxes of only 10 to the 35th erg/sec. The size distribution has an exponential shape, as for other galaxies, with a size scale of 56 pc. The morphologies of different H II regions are discussed and compared to those in other galaxies. Published radio continuum maps compare well with the H-alpha emission distribution. The distribution of H I is also similar in the central areas to the H II with, however, a tendency for the H II regions to lie to one side of H I peaks. 31 refs

  9. An atlas of Calcium triplet spectra of active galaxies

    CERN Document Server

    Garcia-Rissmann, A; Asari, N V; Fernandes, R C; Schmitt, H; González-Delgado, R M; Storchi-Bergmann, T

    2005-01-01

    We present a spectroscopic atlas of active galactic nuclei covering the region around the 8498, 8542, 8662 Calcium triplet (CaT) lines. The sample comprises 78 objects, divided into 43 Seyfert 2s, 26 Seyfert 1s, 3 Starburst and 6 normal galaxies. The spectra pertain to the inner ~300 pc in radius, and thus sample the central kinematics and stellar populations of active galaxies. The data are used to measure stellar velocity dispersions (sigma_star) both with cross-correlation and direct fitting methods. These measurements are found to be in good agreement with each-other and with those in previous studies for objects in common. The CaT equivalent width is also measured. We find average values and sample dispersions of W_CaT of 4.6+/-2.0, 7.0 and 7.7+/-1.0 angstrons for Seyfert 1s, Seyfert 2s and normal galaxies, respectively. We further present an atlas of [SIII]\\lambda 9069 emission line profiles for a subset of 40 galaxies. These data are analyzed in a companion paper which addresses the connection between ...

  10. Powerful Radio Galaxies with Simbol-X: the Nuclear Environment

    Science.gov (United States)

    Torresi, E.; Grandi, P.; Malaguti, G.; Palumbo, G. G. C.; Bianchin, V.

    2009-05-01

    Fanaroff & Riley type II radio galaxies (FRII) are complex objects. In particular FRII Narrow Line Radio Galaxies (NLRG), optically classified as High Excitation Galaxies (HEG) show X-ray spectra very similar to their radio-quiet counterparts, the Seyfert 2 galaxies. They show 2-10 keV continua heavily obscured (NH~1023-24 cm-2) and intense FeKα lines, typical cold matter reprocessing features. Moreover recent Chandra and XMM-Newton observations suggest that the soft X-ray emission of HEG and Seyfert 2 have a common origin from photoionized gas, reinforcing the idea that not only their nuclear engine but also the circumnuclear gas (at least the warm phase) are similar. On the contrary, our knowledge of NLRG HEG above 10 keV is very poor when compared to brighter Seyfert 2. As a consequence, the physical properties of the cold phase of the circumnuclear gas (possibly linked to a dusty torus) are largely unknown. Thanks to its high sensitivity up to 80 keV, Simbol-X will provide very accurate spectra and will allow a direct comparison between the NLRG and Seyfert 2 cold environments.

  11. The oiling of ICS

    International Nuclear Information System (INIS)

    Hunter, S.

    1993-01-01

    The incident command system (ICS) works for oil spills. It should be the industry standard and some will argue that it already is. But there are a number of temptations to fiddle with it. Fueling these inclinations is the fundamental difference between oil spills and natural disasters: Oil spills make the perpetrator fix the problem - under heavy oversight. Add to this difference the public outcry that attends oil spills and the dual role of government as both helper and prosecutor. From these conditions emerge adaptations of ICS which both weaken and strengthen it. The benefits of ICS are diminished by deputy incident commanders who block unified commanders from access to section chiefs, over-zealous crisis managers who displace command post decisions or its information office, separate press offices with party line slants, government law enforcement activity mixed into spill response, nonstandard operations terminology and structure involving open-quotes containment and clean upclose quotes or open-quotes salvage,close quotes and the commingling of public and private response funds. ICS's application to oil spill response is strengthened by the use of trained unified commanders, deputy incident commanders who operate as staff rather than line, crisis managers who support on-scene objectives, joint information centers, and heavy involvement of skilled, prepared environmental assessment teams in the planning section who generate priorities, strategies, and (operationally coordinated) tactics. Technically, not all these points constitute alterations of ICS, but most do and the others come close. This mixed bag of strengthening and weakening tweaks to oil spill ICS provides an opportunity to take a new look at this faithful friend to the crisis responder

  12. Luminosity function of the brightest galaxies in the IRAS survey

    International Nuclear Information System (INIS)

    Soifer, B.T.; Sanders, D.B.; Madore, B.F.; Neugebauer, G.; Persson, C.J.; Persson, S.E.; Rice, W.L.

    1987-01-01

    Results from a study of the far infrared properties of the brightest galaxies in the IRAS survey are described. There is a correlation between the infrared luminosity and the infrared to optical luminosity ratio and between the infrared luminosity and the far infrared color temperature in these galaxies. The infrared bright galaxies represent a significant component of extragalactic objects in the local universe, being comparable in space density to the Seyferts, optically identified starburst galaxies, and more numerous than quasars at the same bolometric luminosity. The far infrared luminosity in the local universe is approximately 25% of the starlight output in the same volume

  13. Observational properties of compact groups of galaxies

    International Nuclear Information System (INIS)

    Hickson, P.

    1990-01-01

    Compact groups are small, relatively isolated, systems of galaxies with projected separations comparable to the diameters of the galaxies themselves. Two well-known examples are Stephan's Quintet (Stephan, 1877) and Seyfert's Sextet (Seyfert 1948a,b). In groups such as these, the apparent space density of galaxies approaches 10(exp 6) Mpc(sub -3), denser even than the cores of rich clusters. The apparent unlikeliness of the chance occurrence of such tight groupings lead Ambartsumyan (1958, 1975) to conclude that compact groups must be physically dense systems. This view is supported by clear signs of galaxy interactions that are seen in many groups. Spectroscopic observations reveal that typical relative velocities of galaxies in the groups are comparable to their internal stellar velocities. This should be conducive to strong gravitational interactions - more so than in rich clusters, where galaxy velocities are typically much higher. This suggests that compact groups could be excellent laboratories in which to study galaxy interactions and their effects. Compact groups often contain one or more galaxies whose redshift differs greatly from those of the other group members. If these galaxies are at the same distance as the other members, either entire galaxies are being ejected at high velocities from these groups, or some new physical phenomena must be occurring. If their redshifts are cosmological, we must explain why so many discordant galaxies are found in compact groups. In recent years much progress has been made in addressing these questions. Here, the author discusses the current observational data on compact groups and their implications

  14. AGB stars as tracers to IC 1613 evolution.

    Science.gov (United States)

    Hashemi, S. A.; Javadi, A.; van Loon, J. Th.

    We are going to apply AGB stars to find star formation history for IC 1613 galaxy; this a new and simple method that works well for nearby galaxies. IC 1613 is a Local Group dwarf irregular galaxy that is located at distance of 750 kpc, a gas rich and isolated dwarf galaxy that has a low foreground extinction. We use the long period variable stars (LPVs) that represent the very final stage of evolution of stars with low and intermediate mass at the AGB phase and are very luminous and cool so that they emit maximum brightness in near-infrared bands. Thus near-infrared photometry with using stellar evolutionary models help us to convert brightness to birth mass and age and from this drive star formation history of the galaxy. We will use the luminosity distribution of the LPVs to reconstruct the star formation history-a method we have successfully applied in other Local Group galaxies. Our analysis shows that the IC 1613 has had a nearly constant star formation rate, without any dominant star formation episode.

  15. Photometric Signatures of Starbursts in Interacting Galaxies and the Butcher-Oemler Effect

    Science.gov (United States)

    Rakos, Karl D.; Maindl, Thomas I.; Schombert, James M.

    1996-01-01

    This paper presents new and synthetic narrow band photometry of ellipticals, spirals, Seyferts and interacting galaxies in an attempt to identify the cause of the unusually high fraction of blue cluster galaxies in distant clusters (the Butcher-Oemler Effect). The properties and distribution of the low redshift sample specifically points to starbursts as the origin of the blue narrow band colors in interacting Arp galaxies.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  17. Mapping Seyfert and LINER Excitation Modes in the Inner kpc of NGC 3393

    Science.gov (United States)

    Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John; Wang, Junfeng; Storchi-Bergmann, Thaisa

    2016-09-01

    We mapped the extended narrowline region (ENLR) of NGC 3393 on scales of r≲ 4\\prime\\prime (˜ 1 kpc) from the nucleus using emission line images of Hα λ6563, [O III]λ 5007, and [S II]λ λ 6717,6731, taken with the Hubble Space Telescope as part of the CHandra survey of Extended Emission line Regions in nearby Seyfert galaxies (CHEERS). By mapping these lines onto a spatially resolved Baldwin-Phillips-Terlevich diagram, we investigate the impact of feedback from a Compton-thick active galactic nucleus on its circumnuclear ISM. We find that the expected Seyfert-like emission within the ionization bicone (≲ 3\\prime\\prime ; 770 pc). We also find a new, figure-8-shaped low ionization emission line region (LINER) cocoon enveloping the bicone and defining a sharp (≲ 100 pc) transition between higher and lower-ionization zones. These data illustrate the morphological dependence of ionization states of the ENLR relative to bicone and host gas geometries.

  18. "Observing" the Circumnuclear Stars and Gas in Disk Galaxy Simulations

    Science.gov (United States)

    Cook, Angela; Hicks, Erin K. S.

    2018-06-01

    We present simulations based on theoretical models of common disk processes designed to represent potential inflow observed within the central 500 pc of local Seyfert galaxies. Mock observations of these n-body plus smoothed particle hydrodynamical simulations provide the conceptual framework in which to identify the driving inflow mechanism, for example nuclear bars, and to quantify to the inflow based on observable properties. From these mock observations the azimuthal average of the flux distribution, velocity dispersion, and velocity of both the stars and interstellar medium on scales of 50pc have been measured at a range of inclinations angles. A comparison of the simulated disk galaxies with these observed azimuthal averages in 40 Seyfert galaxies measured as part of the KONA (Keck OSIRIS Nearby AGN) survey will be presented.

  19. Multiwavelength Monitoring of the Enigmatic Narrow-Line Seyfert 1 PMN J0948 0022 in March-July 2009

    Energy Technology Data Exchange (ETDEWEB)

    Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Axelsson, M.; /Stockholm U. /Stockholm U., OKC; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R. /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bonamente, E. /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, T.H.; /Washington U., Seattle; Caliandro, G.A.; /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /Milan Polytechnic /DAPNIA, Saclay /ASDC, Frascati /INFN, Perugia /Perugia U. /NASA, Goddard /NASA, Goddard /CSST, Baltimore /SISSA, Trieste /Naval Research Lab, Wash., D.C. /George Mason U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Garching, Max Planck Inst., MPE /Stockholm U. /Stockholm U., OKC /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /ASDC, Frascati /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Ecole Polytechnique /Brera Observ. /INFN, Trieste /Bonn, Max Planck Inst., Radioastron. /Hiroshima U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; /more authors..

    2012-03-29

    Following the recent discovery of {gamma} rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z = 0.5846), we started a multiwavelength campaign from radio to {gamma} rays, which was carried out between the end of 2009 March and the beginning of July. The source displayed activity at all the observed wavelengths: a general decreasing trend from optical to {gamma}-ray frequencies was followed by an increase of radio emission after less than two months from the peak of the {gamma}-ray emission. The largest flux change, about a factor of about 4, occurred in the X-ray band. The smallest was at ultraviolet and near-infrared frequencies, where the rate of the detected photons dropped by a factor 1.6-1.9. At optical wavelengths, where the sampling rate was the highest, it was possible to observe day scale variability, with flux variations up to a factor of about 3. The behavior of PMN J0948+0022 observed in this campaign and the calculated power carried out by its jet in the form of protons, electrons, radiation, and magnetic field are quite similar to that of blazars, specifically of flat-spectrum radio quasars. These results confirm the idea that radio-loud narrow-line Seyfert 1 galaxies host relativistic jets with power similar to that of average blazars.

  20. MULTIWAVELENGTH MONITORING OF THE ENIGMATIC NARROW-LINE SEYFERT 1 PMN J0948+0022 IN 2009 MARCH-JULY

    International Nuclear Information System (INIS)

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

    2009-01-01

    Following the recent discovery of γ rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z = 0.5846), we started a multiwavelength campaign from radio to γ rays, which was carried out between the end of 2009 March and the beginning of July. The source displayed activity at all the observed wavelengths: a general decreasing trend from optical to γ-ray frequencies was followed by an increase of radio emission after less than two months from the peak of the γ-ray emission. The largest flux change, about a factor of about 4, occurred in the X-ray band. The smallest was at ultraviolet and near-infrared frequencies, where the rate of the detected photons dropped by a factor 1.6-1.9. At optical wavelengths, where the sampling rate was the highest, it was possible to observe day scale variability, with flux variations up to a factor of about 3. The behavior of PMN J0948+0022 observed in this campaign and the calculated power carried out by its jet in the form of protons, electrons, radiation, and magnetic field are quite similar to that of blazars, specifically of flat-spectrum radio quasars. These results confirm the idea that radio-loud narrow-line Seyfert 1 galaxies host relativistic jets with power similar to that of average blazars.

  1. LeMMINGs - I. The eMERLIN legacy survey of nearby galaxies. 1.5-GHz parsec-scale radio structures and cores

    Science.gov (United States)

    Baldi, R. D.; Williams, D. R. A.; McHardy, I. M.; Beswick, R. J.; Argo, M. K.; Dullo, B. T.; Knapen, J. H.; Brinks, E.; Muxlow, T. W. B.; Aalto, S.; Alberdi, A.; Bendo, G. J.; Corbel, S.; Evans, R.; Fenech, D. M.; Green, D. A.; Klöckner, H.-R.; Körding, E.; Kharb, P.; Maccarone, T. J.; Martí-Vidal, I.; Mundell, C. G.; Panessa, F.; Peck, A. B.; Pérez-Torres, M. A.; Saikia, D. J.; Saikia, P.; Shankar, F.; Spencer, R. E.; Stevens, I. R.; Uttley, P.; Westcott, J.

    2018-05-01

    We present the first data release of high-resolution (≤0.2 arcsec) 1.5-GHz radio images of 103 nearby galaxies from the Palomar sample, observed with the eMERLIN array, as part of the LeMMINGs survey. This sample includes galaxies which are active (low-ionization nuclear emission-line regions [LINER] and Seyfert) and quiescent (H II galaxies and absorption line galaxies, ALGs), which are reclassified based upon revised emission-line diagrams. We detect radio emission ≳0.2 mJy for 47/103 galaxies (22/34 for LINERS, 4/4 for Seyferts, 16/51 for H II galaxies, and 5/14 for ALGs) with radio sizes typically of ≲100 pc. We identify the radio core position within the radio structures for 41 sources. Half of the sample shows jetted morphologies. The remaining half shows single radio cores or complex morphologies. LINERs show radio structures more core-brightened than Seyferts. Radio luminosities of the sample range from 1032 to 1040 erg s-1: LINERs and H II galaxies show the highest and lowest radio powers, respectively, while ALGs and Seyferts have intermediate luminosities. We find that radio core luminosities correlate with black hole (BH) mass down to ˜107 M⊙, but a break emerges at lower masses. Using [O III] line luminosity as a proxy for the accretion luminosity, active nuclei and jetted H II galaxies follow an optical Fundamental Plane of BH activity, suggesting a common disc-jet relationship. In conclusion, LINER nuclei are the scaled-down version of FR I radio galaxies; Seyferts show less collimated jets; H II galaxies may host weak active BHs and/or nuclear star-forming cores; and recurrent BH activity may account for ALG properties.

  2. Simplified design of IC amplifiers

    CERN Document Server

    Lenk, John

    1996-01-01

    Simplified Design of IC Amplifiers has something for everyone involved in electronics. No matter what skill level, this book shows how to design and experiment with IC amplifiers. For experimenters, students, and serious hobbyists, this book provides sufficient information to design and build IC amplifier circuits from 'scratch'. For working engineers who design amplifier circuits or select IC amplifiers, the book provides a variety of circuit configurations to make designing easier.Provides basics for all phases of practical design.Covers the most popular forms for amplif

  3. ESO 113-IG45 galaxy and/or quasar?

    CERN Document Server

    West, R M; Danks, A C

    1978-01-01

    Spectroscopy, UBV photometry and photography have been obtained of the extraordinary 13th magnitude object ESO 113-IG45 identified as a Seyfert galaxy by Fairall (1977); R.A.=01/sup h/ 21/sup m/.9; Decl .=-59 degrees 04' (1950). V/sub 0/=13630+or-50 km s/sup -1/; M/sub V /=-24/sup m/.0; largest diameter 75 kpc or more (with H/sub 0/=55 km s /sup -1/ Mpc/sup -1/). The nucleus is stellar-like and several times more luminous than the surrounding envelope which has a well-developed lane-structure. It is the intrinsically most luminous Seyfert nuclear yet known, and may be described as a 'quasar in the center of a (spiral) galaxy'. It is probably associated with the X-ray source 2A0120-591. (14 refs).

  4. A CHARACTERISTIC DIVISION BETWEEN THE FUELING OF QUASARS AND SEYFERTS: FIVE SIMPLE TESTS

    International Nuclear Information System (INIS)

    Hopkins, Philip F.; Hernquist, Lars

    2009-01-01

    Given the existence of the M BH -σ relation, models of self-regulated black hole (BH) growth require both a fuel supply and concomitant growth of the host bulge to deepen the central potential, or else the system will either starve or immediately self-regulate without any sustained activity. This leads to a generic prediction that the brightest quasars must be triggered in major mergers: a large fraction of the galaxy mass must be added/converted to new bulge mass and a galactic supply of gas must lose angular momentum in less than a dynamical time. Low-luminosity active galactic nuclei, in contrast, require little bulge growth and small gas supplies, and could be triggered in more common nonmerger events. This leads to the expectation of a characteristic transition to merger-induced fueling around the traditional quasar-Seyfert luminosity division (growth of BH masses above/below ∼10 7 M sun ). We compile and survey a number of observations in order to test several predictions of such a division, including (1) a transition to bulge-dominated hosts (which any major merger remnant, regardless of difficult-to-observe tidal features, should be). (2) A transition between 'pseudobulges' and 'classical' bulges hosting the remnant BHs: pseudobulges are formed in secular processes and minor mergers, whereas classical bulges are relics of major mergers. (3) An increase in the amplitude of small-scale clustering (increased halo occupation of small group environments) where mergers are more efficient. (4) Different redshift evolution, with gas-rich merger rates rising to redshifts z > 2 while secular processes are relatively constant in time. (5) An increasing prominence of post-starburst features in more luminous systems. Our compilation of observations in each of these areas provides tentative evidence for the predicted division around the Seyfert-quasar threshold, and we discuss how future observations can improve these constraints and, in combination with the tests

  5. IRAS bright galaxy sample. II. The sample and luminosity function

    International Nuclear Information System (INIS)

    Soifer, B.T.; Sanders, D.B.; Neugebauer, G.; Madore, B.F.; Danielson, G.E.; David Dunlap Observatory, Richmond Hill, Canada; Palomar Observatory; California Institute of Technology, Pasadena)

    1987-01-01

    A statistically complete sample of 324 of the brightest infrared galaxies discovered at 60 microns in the IRAS all-sky survey is described. The results show that far-infrared emission is a significant luminosity component in the local universe, representing 25 percent of the luminosity emitted by stars in the same volume. Above 10 to the 11th solar luminosities, the infrared luminous galaxies are the dominant population of objects in the universe, being as numerous as the Seyfert galaxies and more numerous than quasars at higher luminosities. The infrared luminosity appears to be independent of the optical luminosity of galaxies. Most infrared bright galaxies appear to require much of the interstellar matter to be contributing to the observed infrared luminosity. Approximately 60-80 percent of the far-infrared luminosity of the local universe can be attributed, directly or indirectly, to recent or ongoing star formation. 67 references

  6. Bio-medical CMOS ICs

    CERN Document Server

    Yoo, Hoi-Jun

    2011-01-01

    This book is based on a graduate course entitled, Ubiquitous Healthcare Circuits and Systems, that was given by one of the editors. It includes an introduction and overview to biomedical ICs and provides information on the current trends in research.

  7. An Infrared Method for Discovering AGN: Lick Spectroscopy of New Seyfert I’s in the Kepler Fields

    Science.gov (United States)

    Tsan, Tran; Edelson, Rick; Smith, Krista Lynne; Malkan, Matthew Arnold

    2016-06-01

    Spectra of Active Galactic Nuclei (AGN) candidates in the Kepler fields were observed at Lick Observatory. We used the Shane 3.0-meter telescope with the Kast double spectrograph, covering from 0.35-0.8 μm. Using IRAF, we extracted 1D spectra from the original 2D long-slit images of the candidates. Our main goals are to determine the redshift of the candidates and identify any new AGN. The wavelength and flux calibration are fairly accurate, and most spectra have a good signal-to-noise ratio. Twenty- seven nights of data (consisting of 106 candidates) have been analyzed. For 89% of them, we have determined the redshifts to a precision of δz = 0.0005 in most cases. The rest give inconclusive results. 19 of the candidates turn out to be galactic stars. The most commonly identified emission lines are Hα+[NII], the [OIII] doublet, and Hβ. 44 of the candidates show a Broad Line Region, meaning that their wide permitted lines classify them as either Seyfert I’s or quasars. 6 of these have redshifts above 0.5, indicating that they are highly luminous quasars. One candidate appears to be a bl-lac object. We are now analyzing the Kepler light curves of these Seyfert galaxies.

  8. A NuSTAR survey of nearby ultraluminous infrared galaxies

    DEFF Research Database (Denmark)

    Teng, Stacy H.; Rigby, Jane R.; Stern, Daniel

    2015-01-01

    We present a Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton survey of nine of the nearest ultraluminous infrared galaxies (ULIRGs). The unprecedented sensitivity of NuSTAR at energies above 10 keV enables spectral modeling with far better precision than was previously......] line luminosity than do Seyfert 1 galaxies. We identify IRAS 08572+3915 as another candidate intrinsically X-ray weak source, similar to Mrk 231. We speculate that the X-ray weakness of IRAS 08572+3915 is related to its powerful outflow observed at other wavelengths....

  9. XMM-Newton observation of the NLS1 galaxy Ark 564. I. Spectral analysis of the time-average spectrum

    NARCIS (Netherlands)

    Papadakis, I.E.; Brinkmann, W.; Page, M.J.; McHardy, I.; Uttley, P.

    2007-01-01

    Context: .We present the results from the spectral analysis of the time-average spectrum of the Narrow Line Seyfert 1 (NLS1) galaxy Ark 564 from a ~100 ks XMM-Newton observation. Aims: .Our aim is to characterize accurately the shape of the time-average, X-ray continuum spectrum of the source and

  10. An intermediate-mass black hole in the darf galaxy Pox 52

    Science.gov (United States)

    Barth, Aaron

    2005-01-01

    Do dwarf elliptical and dwarf spiral galaxies contain central black holes with masses below 106 solar masses? Beyond the Local Group dynamical searches for black holes in this mass range are very difficult but the detection of accretion-powered nuclear activity could be used to infer the presence of a black hole. The nearby dwarf spiral galaxy NGC 4395 hosts a faint Seyfert 1 nucleus with a likely black hole mass in the range 104-105 solar masses and for more than a decade it has been the only known example of a Seyfert 1 nucleus in a dwarf galaxy. I will present new Keck spectra of the dwarf galaxy POX 52 which demonstrate that it has a Seyfert 1 spectrum nearly identical to that of NGC 4395. Its velocity dispersion is 37 km/s suggesting a possible black hole mass of order 105 solar masses. I will discuss the prospects for systematic searches for nuclear activity in dwarf galaxies and the implications for black hole demographics.

  11. An Intermediate-Mass Black Hole in the Dwarf Galaxy Pox 52

    Science.gov (United States)

    Barth, Aaron

    Do dwarf elliptical and dwarf spiral galaxies contain central black holes with masses below 106 solar masses? Beyond the Local Group dynamical searches for black holes in this mass range are very difficult but the detection of accretion-powered nuclear activity could be used to infer the presence of a black hole. The nearby dwarf spiral galaxy NGC 4395 hosts a faint Seyfert 1 nucleus with a likely black hole mass in the range 104-105 solar masses and for more than a decade it has been the only known example of a Seyfert 1 nucleus in a dwarf galaxy. I will present new Keck spectra of the dwarf galaxy POX 52 which demonstrate that it has a Seyfert 1 spectrum nearly identical to that of NGC 4395. Its velocity dispersion is 37 km/s suggesting a possible black hole mass of order 105 solar masses. I will discuss the prospects for systematic searches for nuclear activity in dwarf galaxies and the implications for black hole demographics.

  12. SPITZER INFRARED LOW-RESOLUTION SPECTROSCOPIC STUDY OF BURIED ACTIVE GALACTIC NUCLEI IN A COMPLETE SAMPLE OF NEARBY ULTRALUMINOUS INFRARED GALAXIES

    International Nuclear Information System (INIS)

    Imanishi, Masatoshi; Maiolino, Roberto; Nakagawa, Takao

    2010-01-01

    We present the results of Spitzer Infrared Spectrograph low-resolution infrared 5-35 μm spectroscopy of 17 nearby ultraluminous infrared galaxies (ULIRGs) at z 12 L sun , are found in eight sources. We combine these results with those of our previous research to investigate the energy function of buried AGNs in a complete sample of optically non-Seyfert ULIRGs in the local universe at z < 0.3 (85 sources). We confirm a trend that we previously discovered: that buried AGNs are more common in galaxies with higher infrared luminosities. Because optical Seyferts also show a similar trend, we argue more generally that the energetic importance of AGNs is intrinsically higher in more luminous galaxies, suggesting that the AGN-starburst connections are luminosity dependent. This may be related to the stronger AGN feedback scenario in currently more massive galaxy systems, as a possible origin of the galaxy downsizing phenomenon.

  13. Galaxy collisions

    International Nuclear Information System (INIS)

    Combes, F.

    1987-01-01

    Galaxies are not isolated systems of stars and gas, ''independent universes'' as believed by astronomers about ten years ago, but galaxies are formed and evolve by interaction with their environment, and in particular with their nearest neighbors. Gravitational interactions produce enormous tides in the disk of spiral galaxies, generate spiral arms and trigger bursts of star formation. Around elliptical galaxies, the collision with a small companion produces a series of waves, or shells. A galaxy interaction leads, in most cases, to the coalescence of the two coliders; therefore all galaxies are not formed just after the Big-Bang, when matter recombines: second generation galaxies are still forming now by galaxy mergers, essentially elliptical galaxies, but also compact dwarfs. Collisions between galaxies could also trigger activity in nuclei for radiogalaxies and quasars [fr

  14. LUMINOUS BURIED ACTIVE GALACTIC NUCLEI AS A FUNCTION OF GALAXY INFRARED LUMINOSITY REVEALED THROUGH SPITZER LOW-RESOLUTION INFRARED SPECTROSCOPY

    International Nuclear Information System (INIS)

    Imanishi, Masatoshi

    2009-01-01

    We present the results of Spitzer Infrared Spectrograph 5-35 μm low-resolution spectroscopic energy diagnostics of ultraluminous infrared galaxies (ULIRGs) at z> 0.15, classified optically as non-Seyferts. Based on the equivalent widths of polycyclic aromatic hydrocarbon emission and the optical depths of silicate dust absorption features, we searched for signatures of intrinsically luminous, but optically elusive, buried active galactic nuclei (AGNs) in these optically non-Seyfert ULIRGs. We then combined the results with those of non-Seyfert ULIRGs at z IR 12 L sun . We found that the energetic importance of buried AGNs clearly increases with galaxy infrared luminosity, becoming suddenly discernible in ULIRGs with L IR > 10 12 L sun . For ULIRGs with buried AGN signatures, a significant fraction of infrared luminosities can be accounted for by the detected buried AGN and modestly obscured (A V < 20 mag) starburst activity. The implied masses of spheroidal stellar components in galaxies for which buried AGNs become important roughly correspond to the value separating red massive and blue less-massive galaxies in the local universe. Our results may support the widely proposed AGN-feedback scenario as the origin of galaxy downsizing phenomena, where galaxies with currently larger stellar masses previously had higher AGN energetic contributions and star formation originating infrared luminosities, and have finished their major star formation more quickly, due to stronger AGN feedback.

  15. Isolated galaxies

    International Nuclear Information System (INIS)

    Einasto, Maret

    1990-01-01

    To test for the possible presence of really isolated galaxies, which form a randomly distributed population in voids, we compare the distribution of most isolated galaxies in an observed sample with distributions of the same number of random points using the nearest neighbour test. The results show that the random population of really isolated galaxies does not exist - even the most isolated galaxies are connected with systems of galaxies, forming their outlying parts. (author)

  16. PELE-IC test problems

    International Nuclear Information System (INIS)

    Gong, E.Y.; Alexander, E.E.; McMaster, W.H.; Quinones, D.F.

    1979-01-01

    This report provides prospective users of the Lawrence Livermore Laboratory (LLL) fluid-structure interaction computer code, PELE-IC, a variety of test problems for verifying the code on CDC 7600 computer systems at facilities external to the LLL environment. The test problems have been successfully run on CDC 7600 computers at the LLL and Lawrence Berkeley Laboratory (LBL) computer centers

  17. INSPIRALLING SUPERMASSIVE BLACK HOLES: A NEW SIGNPOST FOR GALAXY MERGERS

    International Nuclear Information System (INIS)

    Comerford, Julia M.; Gerke, Brian F.; Newman, Jeffrey A.; Davis, Marc; Yan, Renbin; Cooper, Michael C.; Coil, Alison L.; Faber, S. M.; Koo, David C.; Rosario, D. J.; Dutton, Aaron A.

    2009-01-01

    We present a new technique for observationally identifying galaxy mergers spectroscopically rather than through host galaxy imaging. Our technique exploits the dynamics of supermassive black holes (SMBHs) powering active galactic nuclei (AGNs) in merger-remnant galaxies. Because structure in the universe is built up through galaxy mergers and nearly all galaxies host a central SMBH, some galaxies should possess two SMBHs near their centers as the result of a recent merger. These SMBHs spiral to the center of the resultant merger-remnant galaxy, and one or both of the SMBHs may power AGNs. Using the DEEP2 Galaxy Redshift Survey, we have examined 1881 red galaxies, of which 91 exhibit [O III] and Hβ emission lines indicative of Seyfert 2 activity. Of these, 32 AGNs have [O III] emission-line redshifts significantly different from the redshifts of the host galaxies' stars, corresponding to velocity offsets of ∼50 km s -1 to ∼300 km s -1 . Two of these AGNs exhibit double-peaked [O III] emission lines, while the remaining 30 AGNs each exhibit a single set of velocity-offset [O III] emission lines. After exploring a variety of physical models for these velocity offsets, we argue that the most likely explanation is inspiralling SMBHs in merger-remnant galaxies. Based on this interpretation, we find that roughly half of the red galaxies hosting AGNs are also merger remnants, which implies that mergers may trigger AGN activity in red galaxies. The AGN velocity offsets we find imply a merger fraction of ∼30% and a merger rate of ∼3 mergers Gyr -1 for red galaxies at redshifts 0.34 < z < 0.82.

  18. Deconvolving X-ray spectral variability components in the Seyfert 1.5 NGC 3227

    International Nuclear Information System (INIS)

    Arévalo, P.; Markowitz, A.

    2014-01-01

    We present the variability analysis of a 100 ks XMM-Newton observation of the Seyfert 1.5 active galaxy, NGC 3227. The observation found NGC 3227 in a period where its hard power-law component displayed remarkably little long-term variability. This lucky event allows us to clearly observe a soft spectral component undergoing a large-amplitude but slow flux variation. Using combined spectral and timing analysis, we isolate two independent variable continuum components and characterize their behavior as a function of timescale. Rapid and coherent variations throughout the 0.2-10 keV band reveal a spectrally hard (photon index Γ ∼ 1.7-1.8) power law, dominating the observed variability on timescales of 30 ks and shorter. Another component produces coherent fluctuations in the 0.2-2 keV range and is much softer (Γ ∼ 3); it dominates the observed variability on timescales greater than 30 ks. Both components are viewed through the same absorbers identified in the time-averaged spectrum. The combined spectral and timing analysis breaks the degeneracy between models for the soft excess: it is consistent with a power-law or thermal Comptonized component but not with a blackbody or an ionized reflection component. We demonstrate that the rapid variability in NGC 3227 is intrinsic to continuum-emitting components and is not an effect of variable absorption.

  19. The broad-band X-ray spectrum of IC 4329A from a joint NuSTAR/Suzaku observation

    Energy Technology Data Exchange (ETDEWEB)

    Brenneman, L. W.; Elvis, M. [Harvard-Smithsonian CfA, 60 Garden St., MS-67, Cambridge, MA 02138 (United States); Madejski, G. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Fuerst, F.; Harrison, F. A.; Grefenstette, B. W.; Madsen, K. K.; Rivers, E.; Walton, D. J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Matt, G.; Marinucci, A. [Dipartimento di Matematica e Fisica, Università Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Ballantyne, D. R. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Boggs, S. E. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E.; Craig, W. W. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Stern, D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, W. W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-06-10

    We have obtained a deep, simultaneous observation of the bright, nearby Seyfert galaxy IC 4329A with Suzaku and NuSTAR. Through a detailed spectral analysis, we are able to robustly separate the continuum, absorption, and distant reflection components in the spectrum. The absorbing column is found to be modest (∼6×10{sup 21} cm{sup −2} ), and does not introduce any significant curvature in the Fe K band. We are able to place a strong constraint on the presence of a broadened Fe Kα line (E{sub rest}=6.46{sub −0.07}{sup +0.08} keV with σ=0.33{sub −0.07}{sup +0.08} keV and EW=34{sub −7}{sup +8} eV), though we are not able to constrain any of the parameters of a relativistic reflection model. These results highlight the range in broad Fe K line strengths observed in nearby, bright, active galactic nuclei (roughly an order of magnitude), and imply a corresponding range in the physical properties of the inner accretion disk in these sources. We have also updated our previously reported measurement of the high-energy cutoff of the hard X-ray emission using both observatories rather than just NuSTAR alone: E {sub cut} = 186 ± 14 keV. This high-energy cutoff acts as a proxy for the temperature of the coronal electron plasma, enabling us to further separate this parameter from the plasma's optical depth and to update our results for these parameters as well. We derive kT=50{sub −3}{sup +6} keV with τ=2.34{sub −0.11}{sup +0.16} using a spherical geometry, kT = 61 ± 1 keV with τ = 0.68 ± 0.02 for a slab geometry, with both having an equivalent goodness-of-fit.

  20. Galaxy mergers

    International Nuclear Information System (INIS)

    Roos, N.

    1981-01-01

    This thesis contains a series of four papers dealing with the effects of interactions among galaxies during the epoch of cluster formation. Galaxy interactions are investigated and the results incorporated in numerical simulations of the formation of groups and clusters of galaxies. The role of galaxy interactions is analysed in the more general context of simulations of an expanding universe. The evolution of galaxies in rich clusters is discussed. The results of the investigations are presented and their relation to other work done in the field are briefly reviewed and an attempt is made to link galaxy mergers to the occurrence of activity in galactic nuclei. (Auth.)

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  2. CMOS Analog IC Design: Fundamentals

    OpenAIRE

    Bruun, Erik

    2018-01-01

    This book is intended for use as the main textbook for an introductory course in CMOS analog integrated circuit design. It is aimed at electronics engineering students who have followed basic courses in mathematics, physics, circuit theory, electronics and signal processing. It takes the students directly from a basic level to a level where they can start working on simple analog IC design projects or continue their studies using more advanced textbooks in the field. A distinct feature of thi...

  3. Galaxy Formation

    DEFF Research Database (Denmark)

    Sparre, Martin

    Galaxy formation is an enormously complex discipline due to the many physical processes that play a role in shaping galaxies. The objective of this thesis is to study galaxy formation with two different approaches: First, numerical simulations are used to study the structure of dark matter and how...... galaxies form stars throughout the history of the Universe, and secondly it is shown that observations of gamma-ray bursts (GRBs) can be used to probe galaxies with active star formation in the early Universe. A conclusion from the hydrodynamical simulations is that the galaxies from the stateof...... is important, since it helps constraining chemical evolution models at high redshift. A new project studying how the population of galaxies hosting GRBs relate to other galaxy population is outlined in the conclusion of this thesis. The core of this project will be to quantify how the stellar mass function...

  4. THE M bh-σ DIAGRAM AND THE OFFSET NATURE OF BARRED ACTIVE GALAXIES

    International Nuclear Information System (INIS)

    Graham, Alister W.; Li Ihui

    2009-01-01

    From a sample of 50 predominantly inactive galaxies with direct supermassive black hole mass measurements, it has recently been established that barred galaxies tend to reside rightward of the M bh -σ relation defined by nonbarred galaxies. Either black holes in barred galaxies tend to be anemic or the central velocity dispersions in these galaxies have a tendency to be elevated by the presence of the bar. The latter option is in accord with studies connecting larger velocity dispersions in galaxies with old bars, while the former scenario is at odds with the observation that barred galaxies do not deviate from the M bh -luminosity relation. Using a sample of 88 galaxies with active galactic nuclei, whose supermassive black hole masses have been estimated from their associated emission lines, we reveal for the first time that they also display this same general behavior in the M bh -σ diagram depending on the presence of a bar or not. A new symmetrical and nonsymmetrical 'barless' M bh -σ relation is derived using 82 nonbarred galaxies. The barred galaxies are shown to reside on or up to ∼1 dex below this relation. This may explain why narrow-line Seyfert 1 galaxies appear offset from the 'barless' M bh -σ relation, and has far-reaching implications given that over half of the disk galaxy population are barred.

  5. Watching AGN feedback at its birth: HST observations of nascent outflow host IC860

    Science.gov (United States)

    Alatalo, Katherine

    2016-10-01

    IC860 is a nearby IR-luminous early-type spiral with a unique set of properties: it is a shocked, poststarburst galaxy that hosts an AGN-driven neutral wind and a compact core of molecular gas. IC860 can serve as a rosetta stone for the early stages of triggering AGN feedback. We propose to use WFC3 on HST to obtain NUV, optical and near-IR imaging of IC860. We will create a spatially-resolved history of star formation quenching through SED-fitting of 7 requested broadband filters, and compare the spatially resolved star formation histories to in different positions within the underlying stellar features (such as spiral structure) that might define a narrative of how star formation is quenching in IC860. These observations will also resolve the super-star cluster sites to trace the most recent star formation. Finally, these observations will trace the mass of the outflow by building an absorption map of the dust. IC860 presents a unique opportunity to study a galaxy at an early stage of transitioning from blue spiral to red early-type galaxy, that also hosts an AGN-driven neutral wind and a compact, turbulent molecular gas core.

  6. Properties of hot gas in halos of active galaxies and clusters of galaxies

    International Nuclear Information System (INIS)

    Durret-Isnard, F.

    1982-05-01

    The importance of the inverse Compton effect in the X-ray emission of cluster galaxies is discussed; the X-ray origin problem from galaxy clusters (spectra and emission mechanisms) is studied. The insufficiency of the X-ray bremsstrahlung emission model in an isothermal gas is proved. The ionized halos in narrow-line galaxies (NLG) are studied; after some general points on NLG, one NLG is described and a brief view an emission mechanism models is given; a detailed study of the galaxy IC 5063 and its nebulosity is given: the ionized gas density is calculated together with the evaporation rate for such clouds [fr

  7. Black holes at the centers of nearby dwarf galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Moran, Edward C.; Shahinyan, Karlen; Sugarman, Hannah R.; Vélez, Darik O. [Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States); Eracleous, Michael [Department of Astronomy and Astrophysics, and Institute for Gravitation and the Cosmos, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

    2014-12-01

    Using a distance-limited portion of the Sloan Digital Sky Survey (SDSS) Data Release 7, we have identified 28 active galactic nuclei (AGNs) in nearby (d⩽80 Mpc) low-mass, low-luminosity dwarf galaxies. The accreting objects at the galaxy centers are expected to be intermediate-mass black holes (IMBHs) with M{sub BH}⩽10{sup 6} M{sub ⊙}. The AGNs were selected using several optical emission-line diagnostics after careful modeling of the continuum present in the spectra. We have limited our survey to objects with spectral characteristics similar to those of Seyfert nuclei, excluding emission-line galaxies with ambiguous spectra that could be powered by stellar processes. Thus, as a set, the host galaxies in our sample are the least massive objects in the very local universe certain to contain central black holes. Our sample is dominated by narrow-line (type 2) AGNs, and it appears to have a much lower fraction of broad-line objects than that observed for luminous, optically selected Seyfert galaxies. Given our focus on the nearest objects included in the SDSS, our survey is more sensitive to low-luminosity emission than previous optical searches for AGNs in low-mass galaxies. The [O iii] λ5007 luminosities of the Seyfert nuclei in our sample have a median value of L{sub 5007}=2×10{sup 5} L{sub ⊙} and extend down to ∼10{sup 4} L{sub ⊙}. Using published data for broad-line IMBH candidates, we have derived an [O iii] bolometric correction of log(L{sub bol}/L{sub 5007})=3.0±0.3, which is significantly lower than values obtained for high-luminosity AGNs. Applying this correction to our sample, we obtain minimum black hole mass estimates that fall mainly in the 10{sup 3} M{sub ⊙}–10{sup 4} M{sub ⊙} range, which is roughly where the predicted mass functions for different black hole seed formation scenarios overlap the most. In the stellar mass range that includes the bulk of the AGN host galaxies in our sample, we derive a lower limit on the AGN fraction

  8. Host Galaxy Properties of the Swift BAT Ultra Hard X-Ray Selected AGN

    Science.gov (United States)

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

    2011-01-01

    We have assembled the largest sample of ultra hard X-ray selected (14-195 keV) AGN with host galaxy optical data to date, with 185 nearby (zBAT) sample. The BAT AGN host galaxies have intermediate optical colors (u -- r and g -- r) that are bluer than a comparison sample of inactive galaxies and optically selected AGN from the Sloan Digital Sky Survey (SDSS) which are chosen to have the same stellar mass. Based on morphological classifications from the RC3 and the Galaxy Zoo, the bluer colors of BAT AGN are mainly due to a higher fraction of mergers and massive spirals than in the comparison samples. BAT AGN in massive galaxies (log Stellar Mass >10.5) have a 5 to 10 times higher rate of spiral morphologies than in SDSS AGN or inactive galaxies. We also see enhanced far-IR emission in BAT AGN suggestive of higher levels of star formation compared to the comparison samples. BAT AGN are preferentially found in the most massive host galaxies with high concentration indexes indicative of large bulge-to-disk ratios and large supermassive black holes. The narrow-line (NL) BAT AGN have similar intrinsic luminosities as the SDSS NL Seyferts based on measurements of [O III] Lambda 5007. There is also a correlation between the stellar mass and X-ray emission. The BAT AGN in mergers have bluer colors and greater ultra hard X-ray emission compared to the BAT sample as whole. In agreement with the Unified Model of AGN, and the relatively unbiased nature of the BAT sources, the host galaxy colors and morphologies are independent of measures of obscuration such as X-ray column density or Seyfert type. The high fraction of massive spiral galaxies and galaxy mergers in BAT AGN suggest that host galaxy morphology is related to the activation and fueling of local AGN.

  9. Computing fundamentals IC3 edition

    CERN Document Server

    Wempen, Faithe

    2014-01-01

    Kick start your journey into computing and prepare for your IC3 certification With this essential course book you'll be sending e-mails, surfing the web and understanding the basics of computing in no time. Written by Faithe Wempen, a Microsoft Office Master Instructor and author of more than 120 books, this complete guide to the basics has been tailored to provide comprehensive instruction on the full range of entry-level computing skills. It is a must for students looking to move into almost any profession, as entry-level computing courses have become a compulsory requirement in the modern w

  10. An outflow in the Seyfert ESO 362-G18 revealed by Gemini-GMOS/IFU observations

    Science.gov (United States)

    Humire, Pedro K.; Nagar, Neil M.; Finlez, Carolina; Firpo, Verónica; Slater, Roy; Lena, Davide; Soto-Pinto, Pamela; Muñoz-Vergara, Dania; Riffel, Rogemar A.; Schmitt, Henrique R.; Kraemer, Steven B.; Schnorr-Müller, Allan; Fischer, Travis C.; Robinson, Andrew; Storchi-Bergmann, Thaisa; Crenshaw, Mike; Elvis, Martin S.

    2018-06-01

    We present two-dimensional stellar and gaseous kinematics of the inner 0.7 × 1.2 kpc2 of the Seyfert 1.5 galaxy ESO 362-G18, derived from optical (4092-7338 Å) spectra obtained with the GMOS integral field spectrograph on the Gemini South telescope at a spatial resolution of ≈170 pc and spectral resolution of 36 km s-1. ESO 362-G18 is a strongly perturbed galaxy of morphological type Sa or S0/a, with a minor merger approaching along the NE direction. Previous studies have shown that the [O III] emission shows a fan-shaped extension of ≈10'' to the SE. We detect the [O III] doublet, [N II] and Hα emission lines throughout our field of view. The stellar kinematics is dominated by circular motions in the galaxy plane, with a kinematic position angle of ≈137° and is centred approximately on the continuum peak. The gas kinematics is also dominated by rotation, with kinematic position angles ranging from 122° to 139°, projected velocity amplitudes of the order of 100 km s-1, and a mean velocity dispersion of 100 km s-1. A double-Gaussian fit to the [O III]λ5007 and Hα lines, which have the highest signal to noise ratios of the emission lines, reveal two kinematic components: (1) a component at lower radial velocities which we interpret as gas rotating in the galactic disk; and (2) a component with line of sight velocities 100-250 km s-1 higher than the systemic velocity, interpreted as originating in the outflowing gas within the AGN ionization cone. We estimate a mass outflow rate of 7.4 × 10-2 M⊙ yr-1 in the SE ionization cone (this rate doubles if we assume a biconical configuration), and a mass accretion rate on the supermassive black hole (SMBH) of 2.2 × 10-2 M⊙ yr-1. The total ionized gas mass within 84 pc of the nucleus is 3.3 × 105 M⊙; infall velocities of 34 km s-1 in this gas would be required to feed both the outflow and SMBH accretion. The reduced datacube (FITS file) is only available at the CDS via anonymous ftp to http

  11. SEM probe of IC radiation sensitivity

    Science.gov (United States)

    Gauthier, M. K.; Stanley, A. G.

    1979-01-01

    Scanning Electron Microscope (SEM) used to irradiate single integrated circuit (IC) subcomponent to test for radiation sensitivity can localize area of IC less than .03 by .03 mm for determination of exact location of radiation sensitive section.

  12. Star Formation in the Central Regions of Galaxies

    Science.gov (United States)

    Tsai, Mengchun

    2015-08-01

    The galactic central region connects the galactic nucleus to the host galaxy. If the central black hole co-evolved with the host galaxies, there should be some evidence left in the central region. We use the environmental properties in the central regions such as star-forming activity, stellar population and molecular abundance to figure out a possible scenario of the evolution of galaxies. In this thesis at first we investigated the properties of the central regions in the host galaxies of active and normal galaxies. We used radio emission around the nuclei of the host galaxies to represent activity of active galactic nuclei (AGNs), and used infrared ray (IR) emission to represent the star-forming activity and stellar population of the host galaxies. We determined that active galaxies have higher stellar masses (SMs) within the central kiloparsec radius than normal galaxies do independent of the Hubble types of the host galaxies; but both active and normal galaxies exhibit similar specific star formation rates (SSFRs). We also discovered that certain AGNs exhibit substantial inner stellar structures in the IR images; most of the AGNs with inner structures are Seyferts, whereas only a few LINERs exhibit inner structures. We note that the AGNs with inner structures show a positive correlation between the radio activity of the AGNs and the SFRs of the host galaxies, but the sources without inner structures show a negative correlation between the radio power and the SFRs. These results might be explained with a scenario of starburst-AGN evolution. In this scenario, AGN activities are triggered following a nuclear starburst; during the evolution, AGN activities are accompanied by SF activity in the inner regions of the host galaxies; at the final stage of the evolution, the AGNs might transform into LINERs, exhibiting weak SF activity in the central regions of the host galaxies. For further investigation about the inner structure, we choose the most nearby and luminous

  13. Violence in the hearts of galaxies: aberration or adolescence?

    Science.gov (United States)

    Mundell, Carole G.

    2002-12-01

    Violent activity in the nuclei of galaxies has long been considered a curiosity in its own right; manifestations of this phenomenon include distant quasars in the early Universe and comparatively nearby Seyfert galaxies, both thought to be powered by the release of gravitational potential energy as material from the host galaxy accretes onto a central supermassive black hole (SMBH). Traditionally, the broader study of the formation, structure and evolution of galaxies has largely excluded active galactic nuclei. Recently, however, this situation has changed dramatically, both observationally and theoretically, with the realization that the growth and influence of the SMBH, the origin and development of galaxies and nuclear activity at different epochs in the Universe may be intimately related. The most spectacular fireworks seen in distant quasars may be relatively easy to explain, since the era of greatest quasar activity seems to coincide with turbulent dynamics at the epoch of galaxy formation in the young, gas-rich Universe. Ubiquitous black holes are believed to be a legacy of this violent birth. Alternatively, black holes may be the seeds that drive galaxy formation in the first place. Closer to home, and hence more recently in the history of the Universe, a fraction of comparatively ordinary galaxies, similar to our own, has reignited their central engines, albeit at a lower level of activity. Since these galaxies are more established than their younger and more distant counterparts, the activity here is all the more puzzling. Whatever the mechanisms involved, they are likely to play an important role in galaxy evolution. I review the intriguing evidence for causal links between SMBHs, nuclear activity and the formation and evolution of galaxies, and describe opportunities for testing these relationships using the next generation of earthbound and space-borne astronomical facilities.

  14. Violence in the hearts of galaxies: aberration or adolescence?

    Science.gov (United States)

    Mundell, Carole G

    2002-12-15

    Violent activity in the nuclei of galaxies has long been considered a curiosity in its own right; manifestations of this phenomenon include distant quasars in the early Universe and comparatively nearby Seyfert galaxies, both thought to be powered by the release of gravitational potential energy as material from the host galaxy accretes onto a central supermassive black hole (SMBH). Traditionally, the broader study of the formation, structure and evolution of galaxies has largely excluded active galactic nuclei. Recently, however, this situation has changed dramatically, both observationally and theoretically, with the realization that the growth and influence of the SMBH, the origin and development of galaxies and nuclear activity at different epochs in the Universe may be intimately related. The most spectacular fireworks seen in distant quasars may be relatively easy to explain, since the era of greatest quasar activity seems to coincide with turbulent dynamics at the epoch of galaxy formation in the young, gas-rich Universe. Ubiquitous black holes are believed to be a legacy of this violent birth. Alternatively, black holes may be the seeds that drive galaxy formation in the first place. Closer to home, and hence more recently in the history of the Universe, a fraction of comparatively ordinary galaxies, similar to our own, has reignited their central engines, albeit at a lower level of activity. Since these galaxies are more established than their younger and more distant counterparts, the activity here is all the more puzzling. Whatever the mechanisms involved, they are likely to play an important role in galaxy evolution. I review the intriguing evidence for causal links between SMBHs, nuclear activity and the formation and evolution of galaxies, and describe opportunities for testing these relationships using the next generation of earthbound and space-borne astronomical facilities.

  15. Galaxy formation

    International Nuclear Information System (INIS)

    Gribbin, J.

    1979-01-01

    The current debate on the origin and evolution of galaxies is reviewed and evidence to support the so-called 'isothermal' and 'adiabatic' fluctuation models considered. It is shown that new theories have to explain the formation of both spiral and elliptical galaxies and the reason for their differences. It is stated that of the most recent models the best indicates that rotating spiral galaxies are formed naturally when gas concentrates in the centre of a great halo and forms stars while ellipticals are explained by later interactions between spiral galaxies and merging, which can cancel out the rotation while producing an elliptical galaxy in which the stars, coming from two original galaxies, follow very elliptical, anisotropic orbits. (UK)

  16. NuSTAR reveals the Comptonizing corona of the broad-line radio galaxy 3C 382

    Energy Technology Data Exchange (ETDEWEB)

    Ballantyne, D. R.; Bollenbacher, J. M. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Brenneman, L. W. [Harvard-Smithsonian CfA, 60 Garden Street MS-67, Cambridge, MA 02138 (United States); Madsen, K. K.; Baloković, M.; Harrison, F. A.; Walton, D. J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Boggs, S. E. [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E.; Craig, W. W. [DTU SpaceNational Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Gandhi, P. [Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Lohfink, A. M. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Marinucci, A. [Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy); Markwardt, C. B.; Zhang, W. W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Stern, D., E-mail: david.ballantyne@physics.gatech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2014-10-10

    Broad-line radio galaxies (BLRGs) are active galactic nuclei that produce powerful, large-scale radio jets, but appear as Seyfert 1 galaxies in their optical spectra. In the X-ray band, BLRGs also appear like Seyfert galaxies, but with flatter spectra and weaker reflection features. One explanation for these properties is that the X-ray continuum is diluted by emission from the jet. Here, we present two NuSTAR observations of the BLRG 3C 382 that show clear evidence that the continuum of this source is dominated by thermal Comptonization, as in Seyfert 1 galaxies. The two observations were separated by over a year and found 3C 382 in different states separated by a factor of 1.7 in flux. The lower flux spectrum has a photon-index of Γ=1.68{sub −0.02}{sup +0.03}, while the photon-index of the higher flux spectrum is Γ=1.78{sub −0.03}{sup +0.02}. Thermal and anisotropic Comptonization models provide an excellent fit to both spectra and show that the coronal plasma cooled from kT{sub e} = 330 ± 30 keV in the low flux data to 231{sub −88}{sup +50} keV in the high flux observation. This cooling behavior is typical of Comptonizing corona in Seyfert galaxies and is distinct from the variations observed in jet-dominated sources. In the high flux observation, simultaneous Swift data are leveraged to obtain a broadband spectral energy distribution and indicates that the corona intercepts ∼10% of the optical and ultraviolet emitting accretion disk. 3C 382 exhibits very weak reflection features, with no detectable relativistic Fe Kα line, that may be best explained by an outflowing corona combined with an ionized inner accretion disk.

  17. THE OFF-CENTERED SEYFERT-LIKE COMPACT EMISSION IN THE NUCLEAR REGION OF NGC 3621

    Energy Technology Data Exchange (ETDEWEB)

    Menezes, R. B.; Steiner, J. E.; Silva, Patricia da, E-mail: robertobm@astro.iag.usp.br [Instituto de Astronomia Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Rua do Matão 1226, Cidade Universitária, São Paulo, SP CEP 05508-090 (Brazil)

    2016-02-01

    We analyze an optical data cube of the nuclear region of NGC 3621, taken with the integral field unit of the Gemini Multi-object Spectrograph. We found that the previously detected central line emission in this galaxy actually comes from a blob, located at a projected distance of 2.″14 ± 0.″08 (70.1 ± 2.6 pc) from the stellar nucleus. Only diffuse emission was detected in the rest of the field of view, with a deficit of emission at the position of the stellar nucleus. Diagnostic diagram analysis reveals that the off-centered emitting blob has a Seyfert 2 spectrum. We propose that the line-emitting blob may be a “fossil” emission-line region or a light “echo” from an active galactic nucleus (AGN), which was significantly brighter in the past. Our estimates indicate that the bolometric luminosity of the AGN must have decreased by a factor of ∼13–500 during the past ∼230 yr. A second scenario to explain the morphology of the line-emitting areas in the nuclear region of NGC 3621 involves no decrease of the AGN bolometric luminosity and establishes that the AGN is highly obscured toward the observer but not toward the line-emitting blob. The third scenario proposed here assumes that the off-centered line-emitting blob is a recoiling supermassive black hole, after the coalescence of two black holes. Finally, an additional hypothesis is that the central X-ray source is not an AGN, but an X-ray binary. This idea is consistent with all the scenarios we proposed.

  18. Emission-line galaxies and quasars in the southern hemisphere. I. Description and applications of an objective-prism survey

    International Nuclear Information System (INIS)

    Smith, M.G.

    1975-01-01

    A selection of objects from the first plates of a low-dispersion, objective-prism survey for emission-line galaxies and quasars is used to illustrate the application of the survey to the following lines of research in extragalactic astronomy: quasi-stellar objects, Seyfert galaxies, instabilities in galaxies produced by tidal interaction or explosive events, and rates of star formation and the general chemical evolution of galaxies. Included in the discussion is a description of how the survey provides a new, purely optical, color-independent method for the direct isolation of bright, high-redshift QSOs with strong emission lines (Lα is often directly visible on the Schmidt-survey plates). The newly discovered objects used for illustration are a radio-quiet QSO of redshift 2.07, a luminous, class 2 Seyfert galaxy, a compact blue emission-line galaxy with a jet or streamer, yet with no obvious interacting companion, and a blue galaxy with Hβ flux 50 times that of 30 Doradus, and low metal abundances, which is undergoing a very intense burst of star formation. These objects are to be discussed in greater detail in subsequent papers in this series

  19. Mod 1 ICS TI Report: ICS Conversion of a 140% HPGe Detector

    Energy Technology Data Exchange (ETDEWEB)

    Bounds, John Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-05

    This report evaluates the Mod 1 ICS, an electrically cooled 140% HPGe detector. It is a custom version of the ORTEC Integrated Cooling System (ICS) modified to make it more practical for us to use in the field. Performance and operating characteristics of the Mod 1 ICS are documented, noting both pros and cons. The Mod 1 ICS is deemed a success. Recommendations for a Mod 2 ICS, a true field prototype, are provided.

  20. Galaxy formation

    International Nuclear Information System (INIS)

    Silk, J.; Di Cintio, A.; Dvorkin, I.

    2014-01-01

    Galaxy formation is at the forefront of observation and theory in cosmology. An improved understanding is essential for improving our knowledge both of the cosmological parameters, of the contents of the universe, and of our origins. In these lectures intended for graduate students, galaxy formation theory is reviewed and confronted with recent observational issues. In lecture 1, the following topics are presented: star formation considerations, including IMF, star formation efficiency and star formation rate, the origin of the galaxy luminosity function, and feedback in dwarf galaxies. In lecture 2, we describe formation of disks and massive spheroids, including the growth of supermassive black holes, negative feedback in spheroids, the AGN-star formation connection, star formation rates at high redshift and the baryon fraction in galaxies.

  1. Revealing the nebular properties and Wolf-Rayet population of IC10 with Gemini/GMOS

    Science.gov (United States)

    Tehrani, Katie; Crowther, Paul A.; Archer, I.

    2017-12-01

    We present a deep imaging and spectroscopic survey of the Local Group irregular galaxy IC10 using Gemini North and GMOS to unveil its global Wolf-Rayet (WR) population. We obtain a star formation rate (SFR) of 0.045 ± 0.023 M⊙ yr-1, for IC10 from the nebular H α luminosity, which is comparable to the Small Magellanic Cloud. We also present a revised nebular oxygen abundance of log(O/H) + 12 = 8.40 ± 0.04, comparable to the LMC. It has previously been suggested that for IC10 to follow the WR subtype-metallicity dependance seen in other Local Group galaxies, a large WN population awaits discovery. Our search revealed three new WN stars, and six candidates awaiting confirmation, providing little evidence to support this claim. The new global WR star total of 29 stars is consistent with the Large Magellanic Cloud population when scaled to the reduced SFR of IC10. For spectroscopically confirmed WR stars, the WC/WN ratio is lowered to 1.0; however, including all potential candidates, and assuming those unconfirmed to be WN stars, would reduce the ratio to ∼0.7. We attribute the high WC/WN ratio to the high star formation surface density of IC10 relative to the Magellanic Clouds, which enhances the frequency of high-mass stars capable of producing WC stars.

  2. Wafer level 3-D ICs process technology

    CERN Document Server

    Tan, Chuan Seng; Reif, L Rafael

    2009-01-01

    This book focuses on foundry-based process technology that enables the fabrication of 3-D ICs. The core of the book discusses the technology platform for pre-packaging wafer lever 3-D ICs. However, this book does not include a detailed discussion of 3-D ICs design and 3-D packaging. This is an edited book based on chapters contributed by various experts in the field of wafer-level 3-D ICs process technology. They are from academia, research labs and industry.

  3. ENERGY-DEPENDENT TIME LAGS IN THE SEYFERT 1 GALAXY NGC 4593

    International Nuclear Information System (INIS)

    Sriram, K.; Agrawal, V. K.; Rao, A. R.

    2009-01-01

    We investigate the energy-time lag dependence of the source NGC 4593 using XMM-Newton/EPIC pn data. We found that the time lag dependency is linear in nature with respect to the logarithm of different energy bands. We also investigate the frequency-dependent time lags and identify that at some frequency range (5 x 10 -5 Hz to 2 x 10 -4 Hz) the X-ray emission is highly coherent, mildly frequency dependent, and very strongly energy dependent. These observations can be explained in the framework of the thermal Comptonization process, and they indicate a truncated accretion disk very close to the black hole. We discuss the plausible spectral state to explain the phenomenon and conclude that the observed properties bear a close resemblance to the intermediate state or the steep power-law state, found in galactic black hole sources.

  4. Spectral energy distribution variations of nearby Seyfert galaxies during AGN watch monitoring programs

    Science.gov (United States)

    Kilerci Eser, Ece; Vestergaard, M.

    2018-02-01

    We present and analyse quasi-simultaneous multi-epoch spectral energy distributions (SEDs) of seven reverberation-mapped active galactic nuclei (AGNs) for which accurate black hole mass measurements and suitable archival data are available from the `AGN Watch' monitoring programs. We explore the potential of optical-UV and X-ray data, obtained within 2 d, to provide more accurate SED-based measurements of individual AGN and quantify the impact of source variability on key measurements typically used to characterize the black hole accretion process plus on bolometric correction factors at 5100 Å, 1350 Å and for the 2-10 keV X-ray band, respectively. The largest SED changes occur on long time-scales (≳1 year). For our small sample, the 1μm to 10 keV integrated accretion luminosity typically changes by 10 per cent on short time-scales (over 20 d), by ˜30 per cent over a year, but can change by 100 per cent or more for individual AGN. The extreme ultraviolet (EUV) gap is the most uncertain part of the intrinsic SED, introducing a ˜25 per cent uncertainty in the accretion-induced luminosity, relative to the model independent interpolation method that we adopt. That aside, our analysis shows that the uncertainty in the accretion-induced luminosity, the Eddington luminosity ratio and the bolometric correction factors can be reduced (by a factor of two or more) by use of the SEDs built from data obtained within 20 d. However, \\dot{M} and η are mostly limited by the unknown EUV emission and the unknown details of the central engine and our aspect angle.

  5. Equipartition Jet Model for the Seyfert 1 Galaxy 3C120

    Directory of Open Access Journals (Sweden)

    Siek Hyung

    2003-09-01

    Full Text Available The motion of 3C120 Jet relative to the core is reasonably uniform and the VLBI scale jet connects outwards to a VLA ˜ 100 kpc scale. We measured the jet width variation from the center and found some indication of a power law which indicates the jet expands roughly with a constant opening angle and a constant flow velocity, Vf \\cong c, from subparsec scales to ˜ 100 kpc. With such a constant flow velocity and based on other physical parameters deduced from observed emission characteristics of the jet, we have established an equipartition jet model which might accommodate the basic parameters of the jet on subparsec scales, with which one can fit the radio intensities over all the scale of the jet even to ˜ 100 kpc.

  6. Radiative bow shock wave (?) driven by nuclear ejecta in a Seyfert galaxy

    International Nuclear Information System (INIS)

    Wilson, A.S.; Ulvestad, J.S.; California Institute of Technology, Pasadena)

    1987-01-01

    New VLA maps at 2 cm of the 13-arcsec-scale linear radio source in the center of NGC 1068 are described. The northeast lobe shows a limb-brightened conical morphology, very sharp leading edges, and a magnetic field running parallel to these edges. The spectral index between 2 and 6 cm in these line-brightened regions is near 1.0. The northeast subpeak has a very steep radio spectrum between 18 and 2 cm which is attributed to inverse Compton losses of the relativistic electrons on the infrared photons. The spectral indices in the southwest lobe lie in the range 0.9-1.5 except in its northern parts, where a much larger index is found. The northeast lobe radio emission could arise in either the cocoon of old jet material which has passed through the internal shock in the ejecta and blown out to either side, or in interstellar material compressed by a bow shock wave driven into the galactic ISM. 45 references

  7. VizieR Online Data Catalog: Broad Hβ emission line in 102 Seyfert galaxies (Runco+, 2016)

    Science.gov (United States)

    Runco, J. N.; Cosens, M.; Bennert, V. N.; Scott, B.; Komossa, S.; Malkan, M. A.; Lazarova, M. S.; Auger, M. W.; Treu, T.; Park, D.

    2018-02-01

    A sample of 102 local (0.02=Kast spectrograph and 60 minutes total exposure time per object. The slit was aligned either along the major axis or perpendicular to it. 1D spectra were extracted using a 4 pixel (~3") width centered on the peak flux to mimic the 3" diameter circular fiber of SDSS. (2 data files).

  8. Eleven years of monitoring the Seyfert 1 Mrk 335 with Swift: Characterizing the X-ray and UV/optical variability

    Science.gov (United States)

    Gallo, L. C.; Blue, D. M.; Grupe, D.; Komossa, S.; Wilkins, D. R.

    2018-05-01

    The narrow-line Seyfert 1 galaxy (NLS1) Mrk 335 has been continuously monitored with Swift since May 2007 when it fell into a long-lasting, X-ray low-flux interval. Results from the nearly 11 years of monitoring are presented here. Structure functions are used to measure the UV-optical and X-ray power spectra. The X-ray structure function measured between 10 - 100 days is consistent with the flat, low-frequency part of the power spectrum measured previously in Mrk 335. The UV-optical structure functions of Mrk 335 are comparable with those of other Seyfert 1 galaxies and of Mrk 335 itself when it was in a normal bright state. There is no indication that the current X-ray low-flux state is attributed to changes in the accretion disc structure of Mrk 335. The characteristic timescales measured in the structure functions can be attributed to thermal (for the UV) and dynamic (for the optical) timescales in a standard accretion disc. The high-quality UVW2 (˜1800 Å in the source frame) structure function appears to have two breaks and two different slopes between 10 - 160 days. Correlations between the X-ray and other bands are not highly significant when considering the entire 11-year light curves, but more significant behaviour is present when considering segments of the light curves. A correlation between the X-ray and UVW2 in 2014 (Year-8) may be predominately caused by an giant X-ray flare that was interpreted as jet-like emission. In 2008 (Year-2), possible lags between the UVW2 emission and other UV-optical waveband may be consistent with reprocessing of X-ray or UV emission in the accretion disc.

  9. Anatomy of a merger - CO in Arp 299 (IC 694-NGC 3690)

    International Nuclear Information System (INIS)

    Sargent, A.; Scoville, N.

    1991-01-01

    High-resolution (2.4-arcsec) CO observations of the interacting system Arp 299 (Mrk 171: IC 694 and NGC 3690) reveal major gas condensations at the nuclei of both galaxies and in the disk overlap region. The 0.9 x 10 to the 9th solar masses of H2 at the nucleus of NGC 3690 extends to radii of 310 pc and probably sustains a starburst. A compact source (radius not greater than 250 pc) of mass 3.9 x 10 to the 9th solar masses is found at the nucleus of IC 694; this galaxy may harbor an AGN. At least three discrete subcondensations, probably active star-forming knots, are detected in the 1800 x 640 pc overlap region. 24 refs

  10. Deficiency of normal galaxies among Markaryan galaxies

    International Nuclear Information System (INIS)

    Iyeveer, M.M.

    1986-01-01

    Comparison of the morphological types of Markaryan galaxies and other galaxies in the Uppsala catalog indicates a strong deficiency of normal ellipticals among the Markaryan galaxies, for which the fraction of type E galaxies is ≤ 1% against 10% among the remaining galaxies. Among the Markaryan galaxies, an excess of barred galaxies is observed - among the Markaryan galaxies with types Sa-Scd, approximately half or more have bars, whereas among the remaining galaxies of the same types bars are found in about 1/3

  11. Galaxy Formation

    CERN Document Server

    Longair, Malcolm S

    2008-01-01

    This second edition of Galaxy Formation is an up-to-date text on astrophysical cosmology, expounding the structure of the classical cosmological models from a contemporary viewpoint. This forms the background to a detailed study of the origin of structure and galaxies in the Universe. The derivations of many of the most important results are derived by simple physical arguments which illuminate the results of more advanced treatments. A very wide range of observational data is brought to bear upon these problems, including the most recent results from WMAP, the Hubble Space Telescope, galaxy surveys like the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey, studies of Type 1a supernovae, and many other observations.

  12. The first γ-ray detection of the narrow-line Seyfert 1 FBQS J1644+2619

    International Nuclear Information System (INIS)

    D'Ammando, F.; Istituto Nazionale di Astrofisica; Orienti, M.; Larsson, J.; Giroletti, M.

    2015-01-01

    Here, we report the discovery of γ-ray emission from the narrow-line Seyfert 1 (NLSy1) galaxy FBQS J1644+2619 by the Large Area Telescope on board the Fermi satellite. The Third Fermi LAT Source catalogue reports an unidentified γ-ray source, detected over the first four years of Fermi operation, 0.°23 from the radio position of the NLSy1. Analysing 76 months of γ-ray data (2008 August 4–2014 December 31) we are able to better constrain the localization of the γ-ray source. The new position of the γ- ray source is 0.°05 from FBQS J1644+2619, suggesting a spatial association with the NLSy1. This is the sixth NLSy1 detected at high significance by Fermi-LAT so far. Notably, a significant increase of activity was observed in γ-rays from FBQS J1644+2619 during 2012 July–October, and an increase of activity in V -band was detected by the Catalina Real-Time Sky Survey in the same period.

  13. Imaging the Obscuring Torus in Nearby Active Galaxies

    Science.gov (United States)

    Wilson, Andrew S.; Storchi Bergmann, Thaisa; Morris, Simon

    2000-02-01

    We propose to study a sample of Seyfert galaxies with the aim of resolving spatially the torus of dense molecular gas and dust which is believed to surround the nuclei of these objects. The galaxies, selected to have strong molecular hydrogen emission and jet-like radio continuum sources, will be imaged in various molecular hydrogen lines and in [Fe II] or Br (gamma). The goals are to a) confirm the existence of such tori, b) determine whether the extended molecular gas is excited thermally or through fluorescence, and c) compare with the distribution of ionized gas, which may show an ionization cone structure from polar escape of ionizing photons. The availability of IR imaging capabilities with tip-tilt and narrow-band filters, which allow imaging in the H_2(lambda) 2.122(micron) line up to a recession velocity of 6,000 km s^-1, makes the Blanco 4m telescope very well suited to this project.

  14. ULTRALUMINOUS INFRARED GALAXIES IN THE WISE AND SDSS SURVEYS

    International Nuclear Information System (INIS)

    Su, Shanshan; Kong, Xu; Li, Jinrong; Fang, Guanwen

    2013-01-01

    In this paper, we present a large catalog of 419 Ultraluminous infrared galaxies (ULIRGs), carefully selected from the Wide-field Infrared Survey Explorer mid-infrared data and the Sloan Digital Sky Survey eighth data release, and classify them into three subsamples, based on their emission line properties: H II-like ULIRGs, Seyfert 2 ULIRGs, and composite ULIRGs. We apply our new efficient spectral synthesis technique, which is based on mean field approach to Bayesian independent component analysis (MF-ICA) method, to the galaxy integrated spectra. We also analyze the stellar population properties, including percentage contribution, stellar age, and stellar mass, for these three types of ULIRGs, and explore the evolution among them. We find no significant difference between the properties of stellar populations in ULIRGs with or without active galactic nucleus components. Our results suggest that there is no evolutionary link among these three type ULIRGs

  15. A probabilistic approach to emission-line galaxy classification

    Science.gov (United States)

    de Souza, R. S.; Dantas, M. L. L.; Costa-Duarte, M. V.; Feigelson, E. D.; Killedar, M.; Lablanche, P.-Y.; Vilalta, R.; Krone-Martins, A.; Beck, R.; Gieseke, F.

    2017-12-01

    We invoke a Gaussian mixture model (GMM) to jointly analyse two traditional emission-line classification schemes of galaxy ionization sources: the Baldwin-Phillips-Terlevich (BPT) and WH α versus [N II]/H α (WHAN) diagrams, using spectroscopic data from the Sloan Digital Sky Survey Data Release 7 and SEAGal/STARLIGHT data sets. We apply a GMM to empirically define classes of galaxies in a three-dimensional space spanned by the log [O III]/H β, log [N II]/H α and log EW(H α) optical parameters. The best-fitting GMM based on several statistical criteria suggests a solution around four Gaussian components (GCs), which are capable to explain up to 97 per cent of the data variance. Using elements of information theory, we compare each GC to their respective astronomical counterpart. GC1 and GC4 are associated with star-forming galaxies, suggesting the need to define a new starburst subgroup. GC2 is associated with BPT's active galactic nuclei (AGN) class and WHAN's weak AGN class. GC3 is associated with BPT's composite class and WHAN's strong AGN class. Conversely, there is no statistical evidence - based on four GCs - for the existence of a Seyfert/low-ionization nuclear emission-line region (LINER) dichotomy in our sample. Notwithstanding, the inclusion of an additional GC5 unravels it. The GC5 appears associated with the LINER and passive galaxies on the BPT and WHAN diagrams, respectively. This indicates that if the Seyfert/LINER dichotomy is there, it does not account significantly to the global data variance and may be overlooked by standard metrics of goodness of fit. Subtleties aside, we demonstrate the potential of our methodology to recover/unravel different objects inside the wilderness of astronomical data sets, without lacking the ability to convey physically interpretable results. The probabilistic classifications from the GMM analysis are publicly available within the COINtoolbox at https://cointoolbox.github.io/GMM_Catalogue/.

  16. CO mapping of the nuclear region of NGC 6946 and IC 342 with Nobeyama millimeter array

    Science.gov (United States)

    Ishizuki, Sumio; Kawabe, Ryohei; Okumura, Sachiko K.; Morita, Koh-Ichiro; Ishiguro, Masato

    1990-01-01

    CO observations of nearby galaxies with nuclear active star forming regions (and starburst galaxies) with angular resolutions around 7 seconds revealed that molecular bars with a length of a few kiloparsecs have been formed in the central regions of the galaxies. The molecular bar is interpreted as part of shock waves induced by an oval or barred potential field. By shock dissipation or dissipative cloud-cloud collisions, the molecular gas gains an infall motion and the nuclear star formation activity is fueled. But the distribution and kinematics of the molecular gas in the nuclear regions, which are sites of active star formation, remain unknown. Higher angular resolutions are needed to investigate the gas in the nuclear regions. Researchers made aperture synthesis observations of the nuclear region of the late-type spiral galaxies NGC 6946 and IC 342 with resolutions of 7.6 seconds x 4.2 seconds (P.A. = 147 deg) and 2.4 seconds x 2.3 seconds (P.A. = 149 deg), respectively. The distances to NGC 6496 and IC 342 are assumed to be 5.5 Mpc and 3.9 Mpc, respectively. Researchers have found 100-300 pc nuclear gas disk and ring inside a few kpc molecular gas bars. Researchers present the results of the observations and propose a possible mechanism of active star formation in the nuclear region.

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

    Science.gov (United States)

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

    2017-03-01

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

  18. INTERGALACTIC 'PIPELINE' FUNNELS MATTER BETWEEN COLLIDING GALAXIES

    Science.gov (United States)

    2002-01-01

    in NGC 1409, either. The glancing blow between the galaxies was enough, however, to toss stars deep into space and ignite a rash of star birth in NGC 1410. The arms of NGC 1410, an active, gas-rich spiral galaxy classified as a Seyfert, are awash in blue, the signature color of star-forming regions. The bar of material bisecting the center of NGC 1409 also is a typical byproduct of galaxy collisions. Astronomers expect more fireworks to come. The galaxies are doomed to continue their game of 'bumper cars,' hitting each other and moving apart several times until finally merging in another 200 million years. The galaxies' centers are only 23,000 light-years apart, which is slightly less than Earth's distance from the center of the Milky Way. They are bound together by gravity, orbiting each other at 670,000 miles an hour (1 million kilometers an hour). The galaxies reside about 300 million light-years from Earth in the constellation Taurus. The Hubble picture was taken Oct. 25, 1999. Credits: NASA, William C. Keel (University of Alabama, Tuscaloosa)

  19. A Polarimetric Search for Hidden Quasars in Three Radio-selected Ultraluminous Infrared Galaxies

    International Nuclear Information System (INIS)

    Tran, H.D.; Brotherton, M.S.; Stanford, S.A.; Breugel, W. van; Dey, A.; Stern, D.; Antonucci, R.

    1999-01-01

    We have carried out a spectropolarimetric search for hidden broad-line quasars in three ultraluminous infrared galaxies (ULIRGs) discovered in the positional correlations between sources detected in deep radio surveys and the IRAS Faint Source Catalog. Only the high-ionization Seyfert 2 galaxy TF J1736+1122 is highly polarized, displaying a broad-line spectrum visible in polarized light. The other two objects, TF J1020+6436 and FF J1614+3234, display spectra dominated by a population of young (A type) stars similar to those of open-quotes E+Aclose quotes galaxies. They are unpolarized, showing no sign of hidden broad-line regions. The presence of young starburst components in all three galaxies indicates that the ULIRG phenomenon encompasses both active galactic nuclei (AGNs) and starburst activity, but the most energetic ULIRGs do not necessarily harbor open-quotes buried quasars.close quotes We find that a luminous infrared galaxy is most likely to host an obscured quasar if it exhibits a high-ionization ([O iii] λ5007/Hβ approx-gt 5) spectrum typical of a 'classic' Seyfert 2 galaxy with little or no Balmer absorption lines, is 'ultraluminous' (L IR approx-gt 10 12 L circle-dot ), and has a 'warm' IR color (f 25 /f 60 approx-gt 0.25). The detection of hidden quasars in this group but not in the low-ionization, starburst-dominated ULIRGs (classified as LINERs or H ii galaxies) may indicate an evolutionary connection, with the latter being found in younger systems. copyright copyright 1999. The American Astronomical Society

  20. Unusual broad-line Mg II emitters among luminous galaxies in the baryon oscillation spectroscopic survey

    International Nuclear Information System (INIS)

    Roig, Benjamin; Blanton, Michael R.; Ross, Nicholas P.

    2014-01-01

    Many classes of active galactic nuclei (AGNs) have been observed and recorded since the discovery of Seyfert galaxies. In this paper, we examine the sample of luminous galaxies in the Baryon Oscillation Spectroscopic Survey. We find a potentially new observational class of AGNs, one with strong and broad Mg II λ2799 line emission, but very weak emission in other normal indicators of AGN activity, such as the broad-line Hα, Hβ, and the near-ultraviolet AGN continuum, leading to an extreme ratio of broad Hα/Mg II flux relative to normal quasars. Meanwhile, these objects' narrow-line flux ratios reveal AGN narrow-line regions with levels of activity consistent with the Mg II fluxes and in agreement with that of normal quasars. These AGN may represent an extreme case of the Baldwin effect, with very low continuum and high equivalent width relative to typical quasars, but their ratio of broad Mg II to broad Balmer emission remains very unusual. They may also be representative of a class of AGN where the central engine is observed indirectly with scattered light. These galaxies represent a small fraction of the total population of luminous galaxies (≅ 0.1%), but are more likely (about 3.5 times) to have AGN-like nuclear line emission properties than other luminous galaxies. Because Mg II is usually inaccessible for the population of nearby galaxies, there may exist a related population of broad-line Mg II emitters in the local universe which is currently classified as narrow-line emitters (Seyfert 2 galaxies) or low ionization nuclear emission-line regions.

  1. Supermassive black holes do not correlate with galaxy disks or pseudobulges.

    Science.gov (United States)

    Kormendy, John; Bender, R; Cornell, M E

    2011-01-20

    The masses of supermassive black holes are known to correlate with the properties of the bulge components of their host galaxies. In contrast, they seem not to correlate with galaxy disks. Disk-grown 'pseudobulges' are intermediate in properties between bulges and disks; it has been unclear whether they do or do not correlate with black holes in the same way that bulges do. At stake in this issue are conclusions about which parts of galaxies coevolve with black holes, possibly by being regulated by energy feedback from black holes. Here we report pseudobulge classifications for galaxies with dynamically detected black holes and combine them with recent measurements of velocity dispersions in the biggest bulgeless galaxies. These data confirm that black holes do not correlate with disks and show that they correlate little or not at all with pseudobulges. We suggest that there are two different modes of black-hole feeding. Black holes in bulges grow rapidly to high masses when mergers drive gas infall that feeds quasar-like events. In contrast, small black holes in bulgeless galaxies and in galaxies with pseudobulges grow as low-level Seyfert galaxies. Growth of the former is driven by global processes, so the biggest black holes coevolve with bulges, but growth of the latter is driven locally and stochastically, and they do not coevolve with disks and pseudobulges.

  2. Superclusters and galaxy formation

    International Nuclear Information System (INIS)

    Einasto, J.; Joeveer, M.; Saar, E.

    1979-01-01

    The spatial distribution of Galaxies and Galaxy congestions in the southern galactic hemisphere is studied. The rich galaxy congestions, containing many elliptic Galaxies and radiogalaxies, are linked with each other by chains of scanty congestions with moderate content of elliptic Galaxies and radiogalaxies. The flat formation, linking the density pikes and the intermediate chains, can reasonably be called supercongestion. In the central region of supercongestions there is a thin layer of Galaxies consisting of only spiral Galaxies. The neighbouring supercongestions touch each other, while the intersupercongestion space contains no Galaxy congestions and almost no Galaxies. It is shown that such a structure was, apparently, formed before the formation of Galaxies

  3. Spin orientation for nearby galaxies

    International Nuclear Information System (INIS)

    Karachentsev, I.D.

    1989-01-01

    The spatial orientations and the absolute values of angular momentum are determined for galaxies in the Local Group and the M 81/IC 342 group. For this purpose, the data on both velocity field and the dust knots configuration have been used. The spin direction has been established unambiguously for 21 objects; however, for the remaining 14 dwarf members the spin orientations are presented by pairs of alternative directions. The distribution of the spin vectors on the sky does not slow pronounced sings of anisotropy

  4. S0 galaxies in Formax

    DEFF Research Database (Denmark)

    Bedregal...[], A. G.; Aragón-Salamanca, A.; Merrifield, M. R.

    2006-01-01

    Galaxies: elliptical and lenticular, cD: galaxies: kinematics and dynamics Udgivelsesdato: Oct.1......Galaxies: elliptical and lenticular, cD: galaxies: kinematics and dynamics Udgivelsesdato: Oct.1...

  5. Space density and clustering properties of a new sample of emission-line galaxies

    International Nuclear Information System (INIS)

    Wasilewski, A.J.

    1982-01-01

    A moderate-dispersion objective-prism survey for low-redshift emission-line galaxies has been carried out in an 825 sq. deg. region of sky with the Burrell Schmidt telescope of Case Western Reserve University. A 4 0 prism (300 A/mm at H#betta#) was used with the Illa-J emulsion to show that a new sample of emission-line galaxies is available even in areas already searched with the excess uv-continuum technique. The new emission-line galaxies occur quite commonly in systems with peculiar morphology indicating gravitational interaction with a close companion or other disturbance. About 10 to 15% of the sample are Seyfert galaxies. It is suggested that tidal interaction involving matter infall play a significant role in the generation of an emission-line spectrum. The space density of the new galaxies is found to be similar to the space density of the Makarian galaxies. Like the Markarian sample, the galaxies in the present survey represent about 10% of all galaxies in the absolute magnitude range M/sub p/ = -16 to -22. The observations also indicate that current estimates of dwarf galaxy space densities may be too low. The clustering properties of the new galaxies have been investigated using two approaches: cluster contour maps and the spatial correlation function. These tests suggest that there is weak clustering and possibly superclustering within the sample itself and that the galaxies considered here are about as common in clusters of ordinary galaxies as in the field

  6. A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

    International Nuclear Information System (INIS)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C.; Denney, K. D.; Bentz, M. C.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Bord, D. J.; Che, X.; Chen, C.; Cohen, S. A.

    2012-01-01

    We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II λ4686 broad emission line relative to the optical continuum to be 2.7 ± 0.6 days and the lag in the Hβλ4861 broad emission line to be 13.9 ± 0.9 days. Combined with the line width, the He II lag yields a black hole mass M BH = (2.6 ± 0.8) × 10 7 M ☉ . This measurement is consistent with measurements made using the Hβλ4861 line, suggesting that the He II emission originates in the same structure as Hβ, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

  7. A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

    Energy Technology Data Exchange (ETDEWEB)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Denney, K. D. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); Chen, C.; Cohen, S. A. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); and others

    2012-01-15

    We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II {lambda}4686 broad emission line relative to the optical continuum to be 2.7 {+-} 0.6 days and the lag in the H{beta}{lambda}4861 broad emission line to be 13.9 {+-} 0.9 days. Combined with the line width, the He II lag yields a black hole mass M{sub BH} = (2.6 {+-} 0.8) Multiplication-Sign 10{sup 7} M{sub Sun }. This measurement is consistent with measurements made using the H{beta}{lambda}4861 line, suggesting that the He II emission originates in the same structure as H{beta}, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

  8. RESOLVING THE BRIGHT HCN(1–0) EMISSION TOWARD THE SEYFERT 2 NUCLEUS OF M51: SHOCK ENHANCEMENT BY RADIO JETS AND WEAK MASING BY INFRARED PUMPING?

    International Nuclear Information System (INIS)

    Matsushita, Satoki; Trung, Dinh-V-; Boone, Frédéric; Krips, Melanie; Lim, Jeremy; Muller, Sebastien

    2015-01-01

    We present high angular resolution observations of the HCN(1-0) emission (at ∼1'' or ∼34 pc), together with CO J = 1-0, 2-1, and 3-2 observations, toward the Seyfert 2 nucleus of M51 (NGC 5194). The overall HCN(1-0) distribution and kinematics are very similar to that of the CO lines, which have been indicated as the jet-entrained molecular gas in our past observations. In addition, high HCN(1-0)/CO(1-0) brightness temperature ratio of about unity is observed along the jets, similar to that observed at the shocked molecular gas in our Galaxy. These results strongly indicate that both diffuse and dense gases are entrained by the jets and outflowing from the active galactic nucleus. The channel map of HCN(1-0) at the systemic velocity shows a strong emission right at the nucleus, where no obvious emission has been detected in the CO lines. The HCN(1-0)/CO(1-0) brightness temperature ratio at this region reaches >2, a value that cannot be explained considering standard physical/chemical conditions. Based on our calculations, we suggest infrared pumping and possibly weak HCN masing, but still requiring an enhanced HCN abundance for the cause of this high ratio. This suggests the presence of a compact dense obscuring molecular gas in front of the nucleus of M51, which remains unresolved at our ∼1'' (∼34 pc) resolution, and consistent with the Seyfert 2 classification picture

  9. RESOLVING THE BRIGHT HCN(1–0) EMISSION TOWARD THE SEYFERT 2 NUCLEUS OF M51: SHOCK ENHANCEMENT BY RADIO JETS AND WEAK MASING BY INFRARED PUMPING?

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Satoki [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Trung, Dinh-V- [Institute of Physics, Vietnamese Academy of Science and Technology, 10, Daotan, BaDinh, Hanoi (Viet Nam); Boone, Frédéric [Université de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse (France); Krips, Melanie [Institute de Radio Astronomie Millimétrique, 300 Rue de la Piscine, F-38406 Saint Martin d' Hères (France); Lim, Jeremy [Department of Physics, University of Hong Kong, Pokfulam Road (Hong Kong); Muller, Sebastien [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden)

    2015-01-20

    We present high angular resolution observations of the HCN(1-0) emission (at ∼1'' or ∼34 pc), together with CO J = 1-0, 2-1, and 3-2 observations, toward the Seyfert 2 nucleus of M51 (NGC 5194). The overall HCN(1-0) distribution and kinematics are very similar to that of the CO lines, which have been indicated as the jet-entrained molecular gas in our past observations. In addition, high HCN(1-0)/CO(1-0) brightness temperature ratio of about unity is observed along the jets, similar to that observed at the shocked molecular gas in our Galaxy. These results strongly indicate that both diffuse and dense gases are entrained by the jets and outflowing from the active galactic nucleus. The channel map of HCN(1-0) at the systemic velocity shows a strong emission right at the nucleus, where no obvious emission has been detected in the CO lines. The HCN(1-0)/CO(1-0) brightness temperature ratio at this region reaches >2, a value that cannot be explained considering standard physical/chemical conditions. Based on our calculations, we suggest infrared pumping and possibly weak HCN masing, but still requiring an enhanced HCN abundance for the cause of this high ratio. This suggests the presence of a compact dense obscuring molecular gas in front of the nucleus of M51, which remains unresolved at our ∼1'' (∼34 pc) resolution, and consistent with the Seyfert 2 classification picture.

  10. A combined optical, infrared and radio study of the megamaser galaxy III Zw 35

    International Nuclear Information System (INIS)

    Chapman, J.M.; Axon, D.J.; Cohen, R.J.; Pedlar, A.; Davies, R.D.; Unger, S.W.

    1990-01-01

    III Zw 35 is a pair of galaxies characterized by powerful radio continuum, far-infrared and OH maser radiation. We have made a multi-frequency study of the galaxy pair based on optical, infrared and radio observations. The brighter northern component is identified as an early-type LINER or Seyfert galaxy containing an active nuclear region from which radio continuum, OH maser and thermal dust emission are detected. We propose that the northern component has a compact active nucleus deeply embedded in a highly obscured region of diameter ∼ 210 pc, within which enhanced star-formation occurs. The lower luminosity southern component is of low mass and is undergoing starburst activity over an extended region of diameter ∼ 5.5 kpc. The origin of the starburst and non-thermal activity appears to be an interaction between the two components. (author)

  11. THE NUCLEAR ACTIVITIES OF NEARBY S0 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Meng-Yuan; Gu, Qiu-Sheng; Chen, Yan-Mei; Zhou, Luwenjia, E-mail: qsgu@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093, P. R. China (China)

    2016-11-01

    We present a study of nuclear activities in nearby S0 galaxies. After cross-matching the Sloan Digital Sky Survey Data Release 7 with the Third Reference Catalog of Bright Galaxies (RC3) and visually checking the SDSS images, we derive a sample of 583 S0 galaxies with the central spectrophotometric information. In order to separate nebular emission lines from the underlying stellar contribution, we fit the stellar population model to the SDSS spectra of these S0 galaxies. According to the BPT diagram, we find that 8% of S0 galaxies show central star-forming activity, while the fractions of Seyfert, Composite, and low-ionization nuclear emission-line regions (LINERs) are 2%, 8%, and 21.4%, respectively. We also find that star-forming S0s have the lowest stellar masses, over one magnitude lower than the others, and that the active S0s are mainly located in the sparse environment, while the normal S0s are located in the dense environment, which might suggest that the environment plays an important role in quenching star formation and/or AGN activity in S0 galaxies. By performing bulge-disk decomposition of 45 star-forming S0s in g - and r -bands with the 2D fitting software Galfit, as well as exploiting the catalog of 2D photometric decompositions of Meert et al., we find that the bulges of approximately one-third of star-forming S0 galaxies (16/45) are bluer than their disks, while for other types of S0s the bulge and disk components show similar color distributions. Besides, the Sérsic index of most star-forming S0s bulges is less than two, while for normal S0s, it is between two and six.

  12. THE ROLE OF STARBURST-ACTIVE GALACTIC NUCLEUS COMPOSITES IN LUMINOUS INFRARED GALAXY MERGERS: INSIGHTS FROM THE NEW OPTICAL CLASSIFICATION SCHEME

    International Nuclear Information System (INIS)

    Yuan, T.-T.; Kewley, L. J.; Sanders, D. B.

    2010-01-01

    We investigate the fraction of starbursts, starburst-active galactic nucleus (AGN) composites, Seyferts, and low-ionization narrow emission-line region galaxies (LINERs) as a function of infrared luminosity (L IR ) and merger progress for ∼500 infrared (IR)-selected galaxies. Using the new optical classifications afforded by the extremely large data set of the Sloan Digital Sky Survey, we find that the fraction of LINERs in IR-selected samples is rare ( IR > 10 12 L sun ), starburst-AGN composite galaxies dominate at early-intermediate stages of the merger, and AGN galaxies dominate during the final merger stages. Our results are consistent with models for IR-luminous galaxies where mergers of gas-rich spirals fuel both starburst and AGN, and where the AGN becomes increasingly dominant during the final merger stages of the most luminous IR objects.

  13. The H I chronicles of little things BCDs II: The origin of IC 10's H I structure

    Energy Technology Data Exchange (ETDEWEB)

    Ashley, Trisha; Simpson, Caroline E.; Pokhrel, Nau Raj [Department of Physics, Florida International University, 11200 SW 8th Street, CP 204, Miami, FL 33199 (United States); Elmegreen, Bruce G. [IBM T. J. Watson Research Center, PO Box 218, Yorktown Heights, New York 10598 (United States); Johnson, Megan [CSIRO Astronomy and Space Science P.O. Box 76, Epping, NSW 1710 Australia (Australia); Nidever, David L., E-mail: trisha.l.ashley@nasa.gov, E-mail: simpsonc@fiu.edu, E-mail: npokh001@fiu.edu, E-mail: bge@us.ibm.com, E-mail: megan.johnson@csiro.au, E-mail: dnidever@umich.edu [Department of Astronomy, University of Michigan Ann Arbor, MI, 48109 (United States)

    2014-12-01

    In this paper we analyze Very Large Array (VLA) telescope and Green Bank Telescope (GBT) atomic hydrogen (H I) data for the LITTLE THINGS (Local Irregulars That Trace Luminosity Extremes, The H I Nearby Galaxy Survey; https://science.nrao.edu/science/surveys/littlethings) blue compact dwarf galaxy IC 10. The VLA data allow us to study the detailed H I kinematics and morphology of IC 10 at high resolution while the GBT data allow us to search the surrounding area at high sensitivity for tenuous H I. IC 10's H I appears highly disturbed in both the VLA and GBT H I maps with a kinematically distinct northern H I extension, a kinematically distinct southern plume, and several spurs in the VLA data that do not follow the general kinematics of the main disk. We discuss three possible origins of its H I structure and kinematics in detail: a current interaction with a nearby companion, an advanced merger, and accretion of intergalactic medium. We find that IC 10 is most likely an advanced merger or a galaxy undergoing accretion.

  14. The H I chronicles of little things BCDs II: The origin of IC 10's H I structure

    International Nuclear Information System (INIS)

    Ashley, Trisha; Simpson, Caroline E.; Pokhrel, Nau Raj; Elmegreen, Bruce G.; Johnson, Megan; Nidever, David L.

    2014-01-01

    In this paper we analyze Very Large Array (VLA) telescope and Green Bank Telescope (GBT) atomic hydrogen (H I) data for the LITTLE THINGS (Local Irregulars That Trace Luminosity Extremes, The H I Nearby Galaxy Survey; https://science.nrao.edu/science/surveys/littlethings) blue compact dwarf galaxy IC 10. The VLA data allow us to study the detailed H I kinematics and morphology of IC 10 at high resolution while the GBT data allow us to search the surrounding area at high sensitivity for tenuous H I. IC 10's H I appears highly disturbed in both the VLA and GBT H I maps with a kinematically distinct northern H I extension, a kinematically distinct southern plume, and several spurs in the VLA data that do not follow the general kinematics of the main disk. We discuss three possible origins of its H I structure and kinematics in detail: a current interaction with a nearby companion, an advanced merger, and accretion of intergalactic medium. We find that IC 10 is most likely an advanced merger or a galaxy undergoing accretion.

  15. Mismatch and noise in modern IC processes

    CERN Document Server

    Marshall, Andrew

    2009-01-01

    Component variability, mismatch, and various noise effects are major contributors to design limitations in most modern IC processes. Mismatch and Noise in Modern IC Processes examines these related effects and how they affect the building block circuits of modern integrated circuits, from the perspective of a circuit designer.Variability usually refers to a large scale variation that can occur on a wafer to wafer and lot to lot basis, and over long distances on a wafer. This phenomenon is well understood and the effects of variability are included in most integrated circuit design with the use

  16. Design Developing of IC- Model Using VHDL

    International Nuclear Information System (INIS)

    Inzar-Anas

    2005-01-01

    In present, the electronic design required to become simple, small and flexible. The physical dimension of IC and number of pin can be significantly reduced while the flexibility and compatibility of IC was not change. Implementation of VHDL(VHSIC Hardware Description Language) seem as a great progress in the design of digital circuit. By using this language designing of model can be more simple, flexible and efficient. This paper was purposed to introduce VHDL and its features. Sample in modeling to illustrate the advantage of VHDL will also be described. (author)

  17. Preliminary I&C Design for LORELEI

    International Nuclear Information System (INIS)

    Korotkin, S.; Kaufman, Y.; Guttmann, E. B.; Levy, S.; Amidan, D.; Gdalyho, B.; Cahana, T.; Ellenbogen, A.; Arad, M.; Weiss, Y.; Sasson, A.; Ferry, L.; Bourrelly, F.; Cohen, Y.

    2014-01-01

    This document summarizes the preliminary I&C design for LORELEI experiment The preliminary design deals with considerations regarding appropriate safety and service instrumentation. The determined closed loop control rules for temperature and position will be implemented in the detailed design. The Computer Aided Operator Decisions System (CAODS) will be used for prediction of hot spot temperature and thickness of oxidation layer using Baker-Just correlation. The proposed hybrid simulation system comprising of both virtual and real hardware will be in-cooperated for LORELEI verification. It will perform both integration cold tests for a partial hardware loop and virtual tests for the final I&C design

  18. Abundances of Planetary Nebulae IC 418, IC 2165 and NGC 5882

    NARCIS (Netherlands)

    Pottasch, [No Value; Bernard-Salas, J; Beintema, DA; Feibelman, WA

    The ISO and IUE spectra of the elliptical nebulae NGC 5882, IC 418 and IC 2165 are presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to

  19. CATCHING QUENCHING GALAXIES: THE NATURE OF THE WISE INFRARED TRANSITION ZONE

    Energy Technology Data Exchange (ETDEWEB)

    Alatalo, Katherine; Appleton, Philip N.; Rich, Jeffrey A. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cales, Sabrina L. [Department of Astronomy, Faculty of Physical and Mathematical Sciences, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Kewley, Lisa J. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Lacy, Mark [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Lisenfeld, Ute [Departamento de Física Teórica y del Cosmos, Universidad de Granada, Granada (Spain); Nyland, Kristina, E-mail: kalatalo@caltech.edu [Physics Department, New Mexico Tech, Socorro, NM 87801 (United States)

    2014-10-10

    We present the discovery of a prominent bifurcation between early-type galaxies and late-type galaxies, in [4.6]-[12] μm colors from the Wide Field Infrared Survey Explorer (WISE). We then use an emission-line diagnostic comparison sample to explore the nature of objects found both within and near the edges of this WISE infrared transition zone (IRTZ). We hypothesize that this bifurcation might be due to the presence of hot dust and polyaromatic hydrocarbon (PAH) emission features in late-type galaxies. Using a sample of galaxies selected through the Shocked Poststarburst Galaxy Survey (SPOGS), we are able to identify galaxies with strong Balmer absorption (EW(Hδ) > 5 Å) as well as emission lines inconsistent with star formation (deemed SPOG candidates, or SPOGs*) that lie within the optical green valley. Seyferts and low-ionization nuclear emission line regions, whose u – r colors tend to be red, are strongly represented within IRTZ, whereas SPOGs* tend to sit near the star-forming edge. Although active galactic nuclei are well represented in the IRTZ, we argue that the dominant IRTZ population is composed of galaxies that are in late stages of transitioning across the optical green valley, shedding the last of their remnant interstellar media.

  20. X-ray Point Source Populations in Spiral and Elliptical Galaxies

    Science.gov (United States)

    Colbert, E.; Heckman, T.; Weaver, K.; Strickland, D.

    2002-01-01

    The hard-X-ray luminosity of non-active galaxies has been known to be fairly well correlated with the total blue luminosity since the days of the Einstein satellite. However, the origin of this hard component was not well understood. Some possibilities that were considered included X-ray binaries, extended upscattered far-infrared light via the inverse-Compton process, extended hot 107 K gas (especially in ellipitical galaxies), or even an active nucleus. Chandra images of normal, elliptical and starburst galaxies now show that a significant amount of the total hard X-ray emission comes from individual point sources. We present here spatial and spectral analyses of the point sources in a small sample of Chandra obervations of starburst galaxies, and compare with Chandra point source analyses from comparison galaxies (elliptical, Seyfert and normal galaxies). We discuss possible relationships between the number and total hard luminosity of the X-ray point sources and various measures of the galaxy star formation rate, and discuss possible options for the numerous compact sources that are observed.

  1. Spherical galaxies.

    Science.gov (United States)

    Telles, J. E.; de Souza, R. E.; Penereiro, J. C.

    1990-11-01

    RESUMEN. Presentamos fotometria fotografica de 8 objetos y espectrosco- pla para 3 galaxias, las cuales son buenos candidatos para galaxias esfericas. Los resultados fotometricos se presentan en la forma de iso- fotas y de perfiles radiales promedlo, de los cuales se derivan para- metros estructurales. Estas observaciones combinadas con parametros di- namicos obtenidos de observaciones espectrosc6picas, son consistentes con el plano fundamental derivado por Djorgovski y Davis (1987). ABSTRACT. We present photographic surface photometry for 8 objects and spectroscopy for 3 galaxies which are good candidates for spherical galaxies. Photometric results are presented in the form of isophotes and mean radial profiles from which we derived structural parameters. These observations combined with dynamical parameters obtained from spectroscopic observations are consistent with the fundamental plane derived by Djorgovski and Davis (1987). Keq wo : CALAXIES-ELLIPTICAL

  2. EXPLORING THE LOW-MASS END OF THE MBH-σ* RELATION WITH ACTIVE GALAXIES

    International Nuclear Information System (INIS)

    Xiao Ting; Barth, Aaron J.; Greene, Jenny E.; Ludwig, Randi R.; Ho, Luis C.; Bentz, Misty C.; Jiang Yanfei

    2011-01-01

    We present new measurements of stellar velocity dispersions, using spectra obtained with the Keck Echellette Spectrograph and Imager (ESI) and the Magellan Echellette (MagE), for 76 Seyfert 1 galaxies from the recent catalog of Greene and Ho. These objects were selected from the Sloan Digital Sky Survey (SDSS) to have estimated black hole (BH) masses below 2 x 10 6 M sun . Combining our results with previous ESI observations of similar objects, we obtain an expanded sample of 93 galaxies and examine the relation between BH mass and velocity dispersion (the M BH -σ * relation) for active galaxies with low BH masses. The low-mass active galaxies tend to follow the extrapolation of the M BH -σ * relation of inactive galaxies. Including results for active galaxies of higher BH mass from the literature, we find a zero point α = 7.68 ± 0.08 and slope of β = 3.32 ± 0.22 for the M BH -σ * relation (in the form log M BH = α + βlog (σ * /200 km s -1 )), with intrinsic scatter of 0.46 ± 0.03 dex. This result is consistent, within the uncertainties, with the slope of the M BH -σ * relation for reverberation-mapped active galaxies with BH masses from 10 6 to 10 9 M sun . For the subset of our sample having morphological information from Hubble Space Telescope images, we examine the slope of the M BH -σ * relation separately for subsamples of barred and unbarred host galaxies, and find no significant evidence for a difference in slope. We do find a mild offset between low-inclination and high-inclination disk galaxies, such that more highly inclined galaxies tend to have larger σ * at a given value of BH mass, presumably due to the contribution of disk rotation within the spectroscopic aperture. We also find that the velocity dispersion of the ionized gas, measured from narrow emission lines including [N II] λ6583, [S II] λλ6716, 6731, and the core of [O III] λ5007 (with the blueshifted wing removed), trace the stellar velocity dispersion well for this large

  3. IC 3639 - A New Bona Fide Compton-Thick AGN Unveiled By NuSTAR

    Science.gov (United States)

    Boorman, Peter G.; Gandhi, P.; Alexander, D. M.; Annuar, A.; Ballantyne, D. R.; Bauer, F.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; hide

    2016-01-01

    We analyze high-quality NuSTAR observations of the local (z = 0.011) Seyfert 2 active galactic nucleus (AGN) IC 3639, in conjunction with archival Suzaku and Chandra data. This provides the first broadband X-ray spectral analysis of the source, spanning nearly two decades in energy (0.5-30 keV). Previous X-ray observations of the source below 10 keV indicated strong reflection/obscuration on the basis of a pronounced iron fluorescence line at 6.4 keV. The hard X-ray energy coverage of NuSTAR, together with self-consistent toroidal reprocessing models, enables direct broadband constraints on the obscuring column density of the source. We find the source to be heavily Compton-thick (CTK) with an obscuring column in excess of 3.6 x 10(exp 24) cm(exp -2), unconstrained at the upper end. We further find an intrinsic 2-10 keV luminosity of log(sub 10) (L(sub 2-10 keV) [erg s(exp -1)])= 43.4(+0.6/-1.1) to 90% confidence, almost 400 times the observed flux, and consistent with various multiwavelength diagnostics. Such a high ratio of intrinsic to observed flux, in addition to an Fe-K(alpha) fluorescence line equivalent width exceeding 2 keV, is extreme among known bona fide CTK AGNs, which we suggest are both due to the high level of obscuration present around IC 3639. Our study demonstrates that broadband spectroscopic modeling with NuSTAR enables large corrections for obscuration to be carried out robustly and emphasizes the need for improved modeling of AGN tori showing intense iron fluorescence.

  4. The ACS LCID project. X. the star formation history of IC 1613: Revisiting the over-cooling problem

    Energy Technology Data Exchange (ETDEWEB)

    Skillman, Evan D. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Hidalgo, Sebastian L.; Monelli, Matteo; Gallart, Carme; Aparicio, Antonio, E-mail: skillman@astro.umn.edu, E-mail: shidalgo@iac.es, E-mail: monelli@iac.es, E-mail: carme@iac.es, E-mail: aparicio@iac.es [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38200 La Laguna, Tenerife, Canary Islands (Spain); and others

    2014-05-01

    We present an analysis of the star formation history (SFH) of a field near the half-light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telescope Advanced Camera for Surveys imaging. Our observations reach the oldest main sequence turn-off, allowing a time resolution at the oldest ages of ∼1 Gyr. Our analysis shows that the SFH of the observed field in IC 1613 is consistent with being constant over the entire lifetime of the galaxy. These observations rule out an early dominant episode of star formation in IC 1613. We compare the SFH of IC 1613 with expectations from cosmological models. Since most of the mass is in place at early times for low-mass halos, a naive expectation is that most of the star formation should have taken place at early times. Models in which star formation follows mass accretion result in too many stars formed early and gas mass fractions that are too low today (the 'over-cooling problem'). The depth of the present photometry of IC 1613 shows that, at a resolution of ∼1 Gyr, the star formation rate is consistent with being constant, at even the earliest times, which is difficult to achieve in models where star formation follows mass assembly.

  5. Dwarf spheroidal galaxies: Keystones of galaxy evolution

    Science.gov (United States)

    Gallagher, John S., III; Wyse, Rosemary F. G.

    1994-01-01

    Dwarf spheroidal galaxies are the most insignificant extragalactic stellar systems in terms of their visibility, but potentially very significant in terms of their role in the formation and evolution of much more luminous galaxies. We discuss the present observational data and their implications for theories of the formation and evolution of both dwarf and giant galaxies. The putative dark-matter content of these low-surface-brightness systems is of particular interest, as is their chemical evolution. Surveys for new dwarf spheroidals hidden behind the stars of our Galaxy and those which are not bound to giant galaxies may give new clues as to the origins of this unique class of galaxy.

  6. An X-Ray Luminous, Dwarf Seyfert Companion of Markarian 273 (ApJ, 496, L9 [1998])

    Science.gov (United States)

    Xia, X.-Y.; Boller, Th.; Wu, H.; Deng, Z.-G.; Gao, Y.; Zou, Z.-L.; Mao, S.; Börner, G.

    1998-11-01

    In the Letter ``An X-Ray Luminous, Dwarf Seyfert Companion of Markarian 273'' by X.-Y. Xia, Th. Boller, H. Wu, Z.-G. Deng, Y. Gao, Z.-L. Zou, S. Mao, and G. Börner (ApJ, 496, L9 [1998]), an observational error occurred that invalidates some of our conclusions. Since Mrk 273x was essentially invisible (B~21) in our acqusition image, in order to position the slit on the faint Mrk 273x, a slit rotation had to be applied. Unfortunately, the amount of rotation was applied incorrectly. As a result, the spectrum obtained (shown in Fig. 2) was not for the intended target, Mrk 273x, but for an object very close to, but northeast of, Mrk 273. A new spectrum of Mrk 273x indicates that Mrk 273x is at redshift 0.458, not at 0.0378 as quoted in the Letter. The larger redshift implies that both the optical and X-ray luminosity have to be revised upward by a factor of ~170. Mrk 273x is therefore not a dwarf galaxy optically. The X-ray properties of Mrk 273x remain the same except that its soft X-ray luminosity now reaches ~1044 ergs s-1 for H0=50 km s-1 Mpc-1. The new observations will be presented in a subsequent paper (X.-Y. Xia et al., in preparation [1998]) in order to make corrections and shed further insights on the objects in the Mrk 273 field.

  7. METALLICITY DISTRIBUTION FUNCTIONS OF FOUR LOCAL GROUP DWARF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Teresa L.; Holtzman, Jon [Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States); Saha, Abhijit [NOAO, 950 Cherry Avenue, Tucson, AZ 85726-6732 (United States); Anthony-Twarog, Barbara J., E-mail: rosst@nmsu.edu, E-mail: holtz@nmsu.edu, E-mail: bjat@ku.edu [Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045-7582 (United States)

    2015-06-15

    We present stellar metallicities in Leo I, Leo II, IC 1613, and Phoenix dwarf galaxies derived from medium (F390M) and broad (F555W, F814W) band photometry using the Wide Field Camera 3 instrument on board the Hubble Space Telescope. We measured metallicity distribution functions (MDFs) in two ways, (1) matching stars to isochrones in color–color diagrams and (2) solving for the best linear combination of synthetic populations to match the observed color–color diagram. The synthetic technique reduces the effect of photometric scatter and produces MDFs 30%–50% narrower than the MDFs produced from individually matched stars. We fit the synthetic and individual MDFs to analytical chemical evolution models (CEMs) to quantify the enrichment and the effect of gas flows within the galaxies. Additionally, we measure stellar metallicity gradients in Leo I and II. For IC 1613 and Phoenix our data do not have the radial extent to confirm a metallicity gradient for either galaxy. We find the MDF of Leo I (dwarf spheroidal) to be very peaked with a steep metal-rich cutoff and an extended metal-poor tail, while Leo II (dwarf spheroidal), Phoenix (dwarf transition), and IC 1613 (dwarf irregular) have wider, less peaked MDFs than Leo I. A simple CEM is not the best fit for any of our galaxies; therefore we also fit the “Best Accretion Model” of Lynden-Bell. For Leo II, IC 1613, and Phoenix we find similar accretion parameters for the CEM even though they all have different effective yields, masses, star formation histories, and morphologies. We suggest that the dynamical history of a galaxy is reflected in the MDF, where broad MDFs are seen in galaxies that have chemically evolved in relative isolation and narrowly peaked MDFs are seen in galaxies that have experienced more complicated dynamical interactions concurrent with their chemical evolution.

  8. Chemical evolution of galaxies

    International Nuclear Information System (INIS)

    Vigroux, Laurent

    1979-01-01

    This research thesis addresses theories on the chemical evolution of galaxies which aim at explaining abundances of different elements in galaxies, and more particularly aims at improving the model by modifying hypotheses. After a description of the simple model and of its uncertainties, the author shows how it is possible to understand the evolution of the main elements. Predictions obtained with this model are then compared with the present knowledge on galaxies by considering them according to an increasing complexity: Sun's neighbourhood, our galaxy, other spiral galaxies, elliptical galaxies, and finally galaxy clusters. A specific attention is given to irregular galaxies which are the simplest systems [fr

  9. IC 630: Piercing the Veil of the Nuclear Gas

    Science.gov (United States)

    Durré, Mark; Mould, Jeremy; Schartmann, Marc; Ashraf Uddin, Syed; Cotter, Garrett

    2017-04-01

    IC 630 is a nearby early-type galaxy with a mass of 6× {10}10 M ⊙ with an intense burst of recent (6 Myr) star formation (SF). It shows strong nebular emission lines, with radio and X-ray emission, which classifies it as an active galactic nucleus (AGN). With VLT-SINFONI and Gemini North-NIFS adaptive optics observations (plus supplementary ANU 2.3 m WiFeS optical IFU observations), the excitation diagnostics of the nebular emission species show no sign of standard AGN engine excitation; the stellar velocity dispersion also indicates that a supermassive black hole (if one is present) is small ({M}\\bullet =2.25× {10}5 {M}⊙ ). The luminosity at all wavelengths is consistent with SF at a rate of about 1-2 M ⊙ yr-1. We measure gas outflows driven by SF at a rate of 0.18 M ⊙ yr-1 in a face-on truncated cone geometry. We also observe a nuclear cluster or disk and other clusters. Photoionization from young, hot stars is the main excitation mechanism for [Fe II] and hydrogen, whereas shocks are responsible for the H2 excitation. Our observations are broadly comparable with simulations where a Toomre-unstable, self-gravitating gas disk triggers a burst of SF, peaking after about 30 Myr and possibly cycling with a period of about 200 Myr.

  10. Multiwavelength search and studies of active galaxies and quasars

    Science.gov (United States)

    Mickaelian, Areg M.

    2017-12-01

    The Byurakan Astrophysical Observatory (BAO) has always been one of the centres for surveys and studies of active galaxies. Here we review our search and studies of active galaxies during last 30 years using various wavelength ranges, as well as some recent related works. These projects since late 1980s were focused on multiwavelength search and studies of AGN and Starbursts (SB). 1103 blue stellar objects (BSOs) on the basis of their UV-excess were selected using Markarian Survey (First Byurakan Survey, FBS) plates and Markarian's criteria used for the galaxies. Among many blue stars, QSOs and Seyfert galaxies were found by follow-up observations. 1577 IRAS point sources were optically identified using FBS low-dispersion spectra and many AGN, SB and high-luminosity IR galaxies (LIRG/ULIRG) were discovered. 32 extremely high IR/opt flux ratio galaxies were studies with Spitzer. 2791 ROSAT FSC sources were optically identified using Hamburg Quasar Survey (HQS) low-dispersion spectra and many AGN were discovered by follow-up observations. Fine analysis of emission line spectra was carried out using spectral line decomposition software to establish true profiles and calculate physical parameters for the emitting regions, as well as to study the spectral variability of these objects. X-ray and radio selection criteria were used to find new AGN and variable objects for further studies. We have estimated AGN content of X-ray sources as 52.9%. We have also combined IRAS PSC and FSC catalogs and compiled its extragalactic sample, which allowed us to estimate AGN content among IR sources as 23.7%. Multiwavelength approach allowed revealing many new AGN and SB and obtaining a number of interesting relations using their observational characteristics and physical properties.

  11. SUPER-LUMINOUS TYPE Ic SUPERNOVAE: CATCHING A MAGNETAR BY THE TAIL

    International Nuclear Information System (INIS)

    Inserra, C.; Smartt, S. J.; Jerkstrand, A.; Fraser, M.; Wright, D.; Smith, K.; Chen, T.-W.; Kotak, R.; Nicholl, M.; Valenti, S.; Pastorello, A.; Benetti, S.; Bresolin, F.; Kudritzki, R. P.; Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Botticella, M. T.; Ergon, M.; Fynbo, J. P. U.

    2013-01-01

    We report extensive observational data for five of the lowest redshift Super-Luminous Type Ic Supernovae (SL-SNe Ic) discovered to date, namely, PTF10hgi, SN2011ke, PTF11rks, SN2011kf, and SN2012il. Photometric imaging of the transients at +50 to +230 days after peak combined with host galaxy subtraction reveals a luminous tail phase for four of these SL-SNe. A high-resolution, optical, and near-infrared spectrum from xshooter provides detection of a broad He I λ10830 emission line in the spectrum (+50 days) of SN2012il, revealing that at least some SL-SNe Ic are not completely helium-free. At first sight, the tail luminosity decline rates that we measure are consistent with the radioactive decay of 56 Co, and would require 1-4 M ☉ of 56 Ni to produce the luminosity. These 56 Ni masses cannot be made consistent with the short diffusion times at peak, and indeed are insufficient to power the peak luminosity. We instead favor energy deposition by newborn magnetars as the power source for these objects. A semi-analytical diffusion model with energy input from the spin-down of a magnetar reproduces the extensive light curve data well. The model predictions of ejecta velocities and temperatures which are required are in reasonable agreement with those determined from our observations. We derive magnetar energies of 0.4 ∼ 51 erg) ∼ ej (M ☉ ) ∼< 8.6. The sample of five SL-SNe Ic presented here, combined with SN 2010gx—the best sampled SL-SNe Ic so far—points toward an explosion driven by a magnetar as a viable explanation for all SL-SNe Ic.

  12. Challenges in IC design for hearing aids

    DEFF Research Database (Denmark)

    Jørgensen, Ivan Harald Holger

    2012-01-01

    Designing modern hearing aids is a formidable challenge. The size of hearing aids is constantly decreasing, making them virtually invisible today. Still, as in all other modern electronics, more and more features are added to these devices driven by the development in modern IC technology....... The demands for performance and features at very low supply voltage and power consumption constantly prove a challenge to the physical design of hearing aids and not at least the design of the ICs for these. As a result of this all large hearing aid manufacturers use fully customized ASICs in their products...... to produce a competitive advantage. This presentation will give a brief insight into the hearing aid market and industry, a brief view of the historic development of hearing aids and an introduction to how a modern hearing is constructed showing the amplifier as the key component in the modern hearing aid...

  13. Found: A Galaxy's Missing Gamma Rays

    Science.gov (United States)

    Kohler, Susanna

    2016-04-01

    Recent reanalysis of data from the Fermi Gamma-ray Space Telescope has resulted in the first detection of high-energy gamma rays emitted from a nearby galaxy. This discovery reveals more about how supernovae interact with their environments.Colliding Supernova RemnantAfter a stellar explosion, the supernovas ejecta expand, eventually encountering the ambient interstellar medium. According to models, this generates a strong shock, and a fraction of the kinetic energy of the ejecta is transferred into cosmic rays high-energy radiation composed primarily of protons and atomic nuclei. Much is still unknown about this process, however. One open question is: what fraction of the supernovas explosion power goes into accelerating these cosmic rays?In theory, one way to answer this is by looking for gamma rays. In a starburst galaxy, the collision of the supernova-accelerated cosmic rays with the dense interstellar medium is predicted to produce high-energy gamma rays. That radiation should then escape the galaxy and be visible to us.Pass 8 to the RescueObservational tests of this model, however, have beenstumped by Arp 220. This nearby ultraluminous infrared galaxy is the product of a galaxy merger ~700 million years ago that fueled a frenzy of starbirth. Due to its dusty interior and extreme levels of star formation, Arp 220 has long been predicted to emit the gamma rays produced by supernova-accelerated cosmic rays. But though weve looked, gamma-ray emission has never been detected from this galaxy until now.In a recent study, a team of scientists led by Fang-Kun Peng (Nanjing University) reprocessed 7.5 years of Fermi observations using the new Pass 8 analysis software. The resulting increase in resolution revealed the first detection of GeV emission from Arp 220!Acceleration EfficiencyGamma-ray luminosity vs. total infrared luminosity for LAT-detected star-forming galaxies and Seyferts. Arp 220s luminosities are consistent with the scaling relation. [Peng et al. 2016

  14. Simulation of SEU transients in CMOS ICs

    International Nuclear Information System (INIS)

    Kaul, N.; Bhuva, B.L.; Kerns, S.E.

    1991-01-01

    This paper reports that available analytical models of the number of single-event-induced errors (SEU) in combinational logic systems are not easily applicable to real integrated circuits (ICs). An efficient computer simulation algorithm set, SITA, predicts the vulnerability of data stored in and processed by complex combinational logic circuits to SEU. SITA is described in detail to allow researchers to incorporate it into their error analysis packages. Required simulation algorithms are based on approximate closed-form equations modeling individual device behavior in CMOS logic units. Device-level simulation is used to estimate the probability that ion-device interactions produce erroneous signals capable of propagating to a latch (or n output node), and logic-level simulation to predict the spread of such erroneous, latched information through the IC. Simulation results are compared to those from SPICE for several circuit and logic configurations. SITA results are comparable to this established circuit-level code, and SITA can analyze circuits with state-of-the-art device densities (which SPICE cannot). At all IC complexity levels, SITAS offers several factors of 10 savings in simulation time over SPICE

  15. The DEEP2 Galaxy Redshift Survey: AEGIS observations of a Dual AGNat z = 0.7

    International Nuclear Information System (INIS)

    Gerke1, Brian F.; Newman, Jeffrey A.; Lotz, Jennifer; Yan, Renbin; Barmby, P.; Coil, Alison L.; Conselice, Christopher J.; Ivison, R.J.; Lin, Lihwai; Koo, David C.; Nandra, Kirpal; Salim, Samir; Small, Todd; Weiner, Benjamin J.; Cooper, Michael C.; Davis, Marc; Faber, S.M.; Guhathakurta, Puragra

    2006-01-01

    We present evidence for a dual Active Galactic Nucleus (AGN) within an early-type galaxy at z = 0.709 in the Extended Groth Strip. The galaxy lies on the red sequence, with absolute magnitude M B = -21.0 ( AB, w , with h = 0 0.7) and rest-frame color U - B = 1.38. Its optical spectrum shows strong, double-peaked [O III] emission lines and weak Hβ emission, with Seyfert-like line ratios. The two narrow peaks are separate by 630 km s-1 in velocity and arise from two distinct regions, spatially resolved in the DEIMOS spectrum, with a projected physical separation of 1.2 kpc. HST/ACS imaging shows an early-type (E/S0) galaxy with hints of disturbed structure, consistent with the remnant of a dissipationless merger. Multiwavelength photometric information from the AEGIS consortium confirm the identification of a dust-obscured AGN in an early-type galaxy, with detections in X-ray, optical, infrared and radio wavebands. These data are most readily explained as a single galaxy harboring two AGN--the first such system to be observed in an otherwise typical early-type galaxy

  16. Nuclear Gas Dynamics of NGC2110: A Black Hole Offset from the Host Galaxy Mass Center?

    Science.gov (United States)

    Mundell, C. G.; Ferruit, P.; Nagar, N.; Wilson, A. S.

    2004-01-01

    It has been suggested that the central regions of many galaxies are unlikely to be in a static steady state, with instabilities caused by sinking satellites, the influence of a supermassive black hole or residuals of galaxy formation, resulting in the nuclear black hole orbiting the galaxy center. The observational signature of such an orbiting black hole is an offset of the active nucleus (AGN) from the kinematic center defined by the galaxy rotation curve. This orbital motion may provide fuel for the AGN, as the hole 'grazes' on the ISM, and bent radio jets, due to the motion of their source. The early type (E/SO) Seyfert galaxy, NGC2210, with its striking twin, 'S'-shaped radio jets, is a unique and valuable test case for the offset-nucleus phenomenon since, despite its remarkably normal rotation curve, its kinematically-measured mass center is displaced both spatially (260 pc) and kinematically (170 km/s) from the active nucleus located in optical and radio studies. However, the central kinematics, where the rotation curve rises most steeply, have been inaccessible with ground-based resolutions. We present new, high resolution WFPC2 imaging and long-slit STIS spectroscopy of the central 300 pc of NGC2110. We discuss the structure and kinematics of gas moving in the galactic potential on subarcsecond scales and the reality of the offset between the black hole and the galaxy mass center.

  17. The Unexpected Past of a Dwarf Galaxy

    Science.gov (United States)

    1996-08-01

    understood by Knut Lundmark and P.J. Melotte. The designation WLM is shorthand of Wolf-Lundmark-Melotte. More recent investigations have fixed its distance at about 2.9 million light years, somewhat farther away than the Andromeda galaxy (2 million light years) and placing it at the very edge of the region occupied by the Local Group. WLM is one of the most isolated members; its nearest neighbour dwarf galaxy, IC 1613, is more 1 million light years away. A halo around WLM The ESO astronomers recently obtained deep CCD images of WLM with the 3.5-m ESO New Technology Telescope (NTT) and the ESO Multi-Mode Instrument (EMMI). With the excellent imaging capabilities of this facility, they were able to see large numbers of individual stars in this galaxy. A mosaic of two of these images is reproduced as ESO Press Photo 34/96 that accompanies this Press Release. WLM appears to be quite elongated, and surprisingly, its largest extension is about 8000 light years or more than twice as large as thought before. Nevertheless, this is still 12 times smaller than the Milky Way galaxy. There is a clear excess of very faint stars that extends to the edge of the sky field covered by the NTT exposures. Some of these are probably foreground stars inside the Milky Way, but there are many more than expected, and their numbers increase closer to WLM . These stars look quite different from the ones in the central region of that galaxy: they are much redder and relatively faint; this is a strong indication that they are much older. The distant stars thus appear to belong to an old halo around this dwarf galaxy. This shows that WLM must be very old, perhaps as old as the Milky Way, and in any case much older than indicated by the ages of the stars near its centre. The present discovery furthermore proves that a halo may also form around a dwarf galaxy, and it is not a feature exclusively reserved for large spiral galaxies. Implications of this discovery WLM is so isolated that it has most probably

  18. High energy ion implantation for IC processing

    International Nuclear Information System (INIS)

    Oosterhoff, S.

    1986-01-01

    In this thesis the results of fundamental research on high energy ion implantation in silicon are presented and discussed. The implantations have been carried out with the 500 kV HVEE ion implantation machine, that was acquired in 1981 by the IC technology and Electronics group at Twente University of Technology. The damage and anneal behaviour of 1 MeV boron implantations to a dose of 10 13 /cm 2 have been investigated as a function of anneal temperature by sheet resistance, Hall and noise measurements. (Auth.)

  19. Galaxy angular momentum

    International Nuclear Information System (INIS)

    Thompson, L.A.

    1974-01-01

    In order to test the theories which purport to explain the origin of galaxy angular momentum, this study presents new data for about 1000 individual galaxies in eight rich clusters. The clusters which are studied include Virgo, A 119, A 400, A 1656 (Coma), A 2147, A 2151 (Hercules), A 2197, and A 2199. Selected samples of these data are used to investigate systematic alignment effects in clusters of galaxies and to investigate the intrinsic ellipticities of E, SO, and spiral galaxies. The following new results are reported: Galaxies in the cluster A 2197 show a significant alignment effect (chi 2 probability less than 0.0002), and the preferential direction of alignment corresponds approximately to the major axis of the overall cluster elongation. None of the other seven clusters show any significant alignment trends. The spiral galaxy samples in four clusters (Virgo, A 1656, A 2151, and A 2197) were large enough to analyze the number distributions of forward and reverse winding spirals. Large and small spiral galaxies have identical ellipticity distributions. Large E and SO galaxies tend to be more spherical, and small E and SO galaxies more flattened. The intrinsic ellipticities of E, SO, and spiral galaxies are the same for galaxies in the ''field'' and for galaxies in rich clusters. Six models of galaxy formation are reviewed, and the major []mphasis is placed on how each model explains the origin of galaxy angular momentum. (Diss. Abstr. Int., B)

  20. Substance accretion onto supermassive black holes and X radiation of active galaxy nuclei

    International Nuclear Information System (INIS)

    Zentsova, A.S.

    1980-01-01

    The X-ray radiation of quasars and Seyfert galaxies is explained on the ground of the two-temperature model of the disk accretion onto a supermassive black hole. The inner region of the disk is optically thin to absorption, gas-pressure dominated and the electron temperature is approximately 5x10 8 K and ion temperature is approximately 10 3 times higher. X radiation is produced by inverse Compton scatetring of soft radiation in the inner region of the disk. The source of soft radiation is the outer region of the disk. This model predicts a power spectrum of the radiation from 1 to 60 keV with the index γ=1, the latter approaches to a mean spectral index of X radiation of active galaxy nuclei [ru

  1. Infrared tip of the red giant branch and distances to the MAFFEI/IC 342 group

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Po-Feng; Tully, R. Brent; Jacobs, Bradley A. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, HI 96822 (United States); Rizzi, Luca [W. M. Keck Observatory, 65-1120 Mamalahoa Hwy, Kamuela, HI 96743 (United States); Dolphin, Andrew E. [Raytheon, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Karachentsev, Igor D. [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnij Arkhyz, Karachai-Cherkessian Republic 369167 (Russian Federation)

    2014-07-01

    In this paper, we extend the use of the tip of the red giant branch (TRGB) method to near-infrared wavelengths from the previously used I-band, using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3). Upon calibration of a color dependency of the TRGB magnitude, the IR TRGB yields a random uncertainty of ∼5% in relative distance. The IR TRGB methodology has an advantage over the previously used Advance Camera for Surveys F606W and F814W filter set for galaxies that suffer from severe extinction. Using the IR TRGB methodology, we obtain distances toward three principal galaxies in the Maffei/IC 342 complex, which are located at low Galactic latitudes. New distance estimates using the TRGB method are 3.45{sub −0.13}{sup +0.13} Mpc for IC 342, 3.37{sub −0.23}{sup +0.32} Mpc for Maffei 1, and 3.52{sub −0.30}{sup +0.32} Mpc for Maffei 2. The uncertainties are dominated by uncertain extinction, especially for Maffei 1 and Maffei 2. Our IR calibration demonstrates the viability of the TRGB methodology for observations with the James Webb Space Telescope.

  2. An Optical Low-frequency Quasi-Periodic Oscillation in the Kepler Light Curve of an Active Galaxy

    Science.gov (United States)

    Mushotzky, Richard; Smith, Krista Lynne; Boyd, Patricia; Wagoner, Robert

    2018-01-01

    We report the discovery of a candidate quasi-periodic oscillation (QPO) in the optical light curve of KIC 9650712, a Seyfert 1 galaxy in the original Kepler field. After the development and application of a pipeline for Kepler data specific to active galactic nuclei (AGN), one of our sample of 21 AGN selected by infrared photometry and X-ray flux demonstrates a peak in the power spectrum at 10-6.58 Hz, corresponding to a temporal period of 44 days. >From optical spectroscopy, we measure the black hole mass of this AGN as log M = 8.17 M_sun. Despite this high mass, the optical spectrum of KIC 9650712 bears many similarities to Narrow Line Seyfert 1 (NLS1) galaxies, including strong Fe II emission and a low [O III]/Hβ ratio. So far, X-ray QPOs have primarily been seen in NLS1 galaxies. Finally, we find that this frequency lies along a correlation between low-frequency QPOs and black hole mass from stellar and intermediate mass black holes to AGN, similar to the known correlation in high-frequency QPOs.

  3. PDC IC WELD FAILURE EVALUATION AND RESOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Korinko, P.; Howard, S.; Maxwell, D.; Fiscus, J.

    2012-04-16

    During final preparations for start of the PDCF Inner Can (IC) qualification effort, welding was performed on an automated weld system known as the PICN. During the initial weld, using a pedigree canister and plug, a weld defect was observed. The defect resulted in a hole in the sidewall of the canister, and it was observed that the plug sidewall had not been consumed. This was a new type of failure not seen during development and production of legacy Bagless Transfer Cans (FB-Line/Hanford). Therefore, a team was assembled to determine the root cause and to determine if the process could be improved. After several brain storming sessions (MS and T, R and D Engineering, PDC Project), an evaluation matrix was established to direct this effort. The matrix identified numerous activities that could be taken and then prioritized those activities. This effort was limited by both time and resources (the number of canisters and plugs available for testing was limited). A discovery process was initiated to evaluate the Vendor's IC fabrication process relative to legacy processes. There were no significant findings, however, some information regarding forging/anneal processes could not be obtained. Evaluations were conducted to compare mechanical properties of the PDC canisters relative to the legacy canisters. Some differences were identified, but mechanical properties were determined to be consistent with legacy materials. A number of process changes were also evaluated. A heat treatment procedure was established that could reduce the magnetic characteristics to levels similar to the legacy materials. An in-situ arc annealing process was developed that resulted in improved weld characteristics for test articles. Also several tack welds configurations were addressed, it was found that increasing the number of tack welds (and changing the sequence) resulted in decreased can to plug gaps and a more stable weld for test articles. Incorporating all of the process

  4. Scalable IC Platform for Smart Cameras

    Directory of Open Access Journals (Sweden)

    Harry Broers

    2005-08-01

    Full Text Available Smart cameras are among the emerging new fields of electronics. The points of interest are in the application areas, software and IC development. In order to reduce cost, it is worthwhile to invest in a single architecture that can be scaled for the various application areas in performance (and resulting power consumption. In this paper, we show that the combination of an SIMD (single-instruction multiple-data processor and a general-purpose DSP is very advantageous for the image processing tasks encountered in smart cameras. While the SIMD processor gives the very high performance necessary by exploiting the inherent data parallelism found in the pixel crunching part of the algorithms, the DSP offers a friendly approach to the more complex tasks. The paper continues to motivate that SIMD processors have very convenient scaling properties in silicon, making the complete, SIMD-DSP architecture suitable for different application areas without changing the software suite. Analysis of the changes in power consumption due to scaling shows that for typical image processing tasks, it is beneficial to scale the SIMD processor to use the maximum level of parallelism available in the algorithm if the IC supply voltage can be lowered. If silicon cost is of importance, the parallelism of the processor should be scaled to just reach the desired performance given the speed of the silicon.

  5. Studying Radiation Tolerant ICs for LHC

    CERN Multimedia

    Faccio, F; Snoeys, W; Campbell, M; Casas-cubillos, J; Gomes, P

    2002-01-01

    %title\\\\ \\\\In the recent years, intensive work has been carried out on the development of custom ICs for the readout electronics for LHC experiments. As far as radiation hardness is concerned, attention has been focussed on high total dose applications, mainly for the tracker systems. The dose foreseen in this inner region is estimated to be higher than 1~Mrad/year. In the framework of R&D projects (RD-9 and RD-20) and in the ATLAS and CMS experiments, the study of different radiation hard processes has been pursued and good contacts with the manufacturers have been established. The results of these studies have been discussed during the Microelectronics User Group (MUG) rad-hard meetings, and now some HEP groups are working to develop radiation hard ICs for the LHC experiments on some of the available rad-hard processes.\\\\ \\\\In addition, a lot of the standard commercial electronic components and ASICs which are planned to be installed near the LHC machine and in the detectors will receive total doses in ...

  6. Electron Storage Ring Development for ICS Sources

    Energy Technology Data Exchange (ETDEWEB)

    Loewen, Roderick [Lyncean Technologies, Inc., Palo Alto, CA (United States)

    2015-09-30

    There is an increasing world-wide interest in compact light sources based on Inverse Compton Scattering. Development of these types of light sources includes leveraging the investment in accelerator technology first developed at DOE National Laboratories. Although these types of light sources cannot replace the larger user-supported synchrotron facilities, they offer attractive alternatives for many x-ray science applications. Fundamental research at the SLAC National Laboratory in the 1990’s led to the idea of using laser-electron storage rings as a mechanism to generate x-rays with many properties of the larger synchrotron light facilities. This research led to a commercial spin-off of this technology. The SBIR project goal is to understand and improve the performance of the electron storage ring system of the commercially available Compact Light Source. The knowledge gained from studying a low-energy electron storage ring may also benefit other Inverse Compton Scattering (ICS) source development. Better electron storage ring performance is one of the key technologies necessary to extend the utility and breadth of applications of the CLS or related ICS sources. This grant includes a subcontract with SLAC for technical personnel and resources for modeling, feedback development, and related accelerator physics studies.

  7. Conceptualising Intellectual Capital (IC) as Language Game and Power

    DEFF Research Database (Denmark)

    Jørgensen, Kenneth Mølbjerg

    2006-01-01

    Intellectual Capital (IC) can be viewed as knowledge about knowledge, knowledge creation and how such processes might be leveraged into value. Developing a critical understanding of IC requires a historical and contextual understanding of how IC has emerged and how IC is used. This paper, drawing...... this process of social construction. The paper concludes by proposing some methodological guidelines for conducting critical genealogical research on intellectual capital....

  8. Polar ring galaxies in the Galaxy Zoo

    Science.gov (United States)

    Finkelman, Ido; Funes, José G.; Brosch, Noah

    2012-05-01

    We report observations of 16 candidate polar-ring galaxies (PRGs) identified by the Galaxy Zoo project in the Sloan Digital Sky Survey (SDSS) data base. Deep images of five galaxies are available in the SDSS Stripe82 data base, while to reach similar depth we observed the remaining galaxies with the 1.8-m Vatican Advanced Technology Telescope. We derive integrated magnitudes and u-r colours for the host and ring components and show continuum-subtracted Hα+[N II] images for seven objects. We present a basic morphological and environmental analysis of the galaxies and discuss their properties in comparison with other types of early-type galaxies. Follow-up photometric and spectroscopic observations will allow a kinematic confirmation of the nature of these systems and a more detailed analysis of their stellar populations.

  9. Star Formation in Irregular Galaxies.

    Science.gov (United States)

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  10. Combining Galaxy-Galaxy Lensing and Galaxy Clustering

    Energy Technology Data Exchange (ETDEWEB)

    Park, Youngsoo [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Krause, Elisabeth [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Dodelson, Scott [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Jain, Bhuvnesh [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Amara, Adam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Becker, Matt [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Bridle, Sarah [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Clampitt, Joseph [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Crocce, Martin [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Honscheid, Klaus [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Gaztanaga, Enrique [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Sanchez, Carles [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Wechsler, Risa [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-01-01

    Combining galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth rate of large scale structure, a quantity that will shed light on the mechanism driving the acceleration of the Universe. The Dark Energy Survey (DES) is a prime candidate for such an analysis, with its measurements of both the distribution of galaxies on the sky and the tangential shears of background galaxies induced by these foreground lenses. By constructing an end-to-end analysis that combines large-scale galaxy clustering and small-scale galaxy-galaxy lensing, we also forecast the potential of a combined probes analysis on DES datasets. In particular, we develop a practical approach to a DES combined probes analysis by jointly modeling the assumptions and systematics affecting the different components of the data vector, employing a shared halo model, HOD parametrization, photometric redshift errors, and shear measurement errors. Furthermore, we study the effect of external priors on different subsets of these parameters. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/ optimistically constraining the growth function to 8%/4.9% with its first-year data covering 1000 square degrees, and to 4%/2.3% with its full five-year data covering 5000 square degrees.

  11. Formation of galaxies

    International Nuclear Information System (INIS)

    Szalay, A.S.

    1984-12-01

    The present theories of galaxy formation are reviewed. The relation between peculiar velocities and the correlation function of galaxies points to the possibility that galaxies do not form uniformly everywhere. Scale invariant properties of the cluster-cluster correlations are discussed. Comparing the correlation functions in a dimensionless way, galaxies appear to be stronger clustered, in contrast with the comparison of the dimensional amplitudes of the correlation functions. Theoretical implications of several observations as Lyman-α clouds, correlations of faint galaxies are discussed. None of the present theories of galaxy formation can account for all facts in a natural way. 29 references

  12. Too Fast, Too Furious: A Galaxy's Fatal Plunge

    Science.gov (United States)

    2004-01-01

    multimillion-degree trail of gas. Chandra's data indicate that this hot gas was probably enriched in heavy elements by the starburst and driven out of the galaxy by its supersonic motion through the much larger cloud of gas that pervades the cluster. Collectively, these observations offer evidence that the ram pressure of external gas in the cluster is stripping away the galaxy's own gas. This process has long been hypothesized to account for the forced evolution of cluster galaxies. Its aftermath has been seen in several ways. Some nearby examples, Seyfert's Sextet and Stefan's Quintet, are tight clusters that show the aftermath of high-velocity collisions. The galaxy C153 is destined to lose the last vestiges of its spiral arms and become a bland S0-type galaxy having a central bulge and disk, but no spiral-arm structure. These types of galaxies are common in the dense galaxy clusters seen today. Astronomers plan to make new observations with Gemini again in 2004 to study the dynamics of the gas and stars in the tail. The science team members are William Keel (University of Alabama), Frazer Owen (National Radio Astronomy Observatory), Michael Ledlow (Gemini Observatory), and Daniel Wang (University of Massachusetts). NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

  13. BULGELESS GIANT GALAXIES CHALLENGE OUR PICTURE OF GALAXY FORMATION BY HIERARCHICAL CLUSTERING ,

    International Nuclear Information System (INIS)

    Kormendy, John; Cornell, Mark E.; Drory, Niv; Bender, Ralf

    2010-01-01

    To better understand the prevalence of bulgeless galaxies in the nearby field, we dissect giant Sc-Scd galaxies with Hubble Space Telescope (HST) photometry and Hobby-Eberly Telescope (HET) spectroscopy. We use the HET High Resolution Spectrograph (resolution R ≡ λ/FWHM ≅ 15, 000) to measure stellar velocity dispersions in the nuclear star clusters and (pseudo)bulges of the pure-disk galaxies M 33, M 101, NGC 3338, NGC 3810, NGC 6503, and NGC 6946. The dispersions range from 20 ± 1 km s -1 in the nucleus of M 33 to 78 ± 2 km s -1 in the pseudobulge of NGC 3338. We use HST archive images to measure the brightness profiles of the nuclei and (pseudo)bulges in M 101, NGC 6503, and NGC 6946 and hence to estimate their masses. The results imply small mass-to-light ratios consistent with young stellar populations. These observations lead to two conclusions. (1) Upper limits on the masses of any supermassive black holes are M . ∼ 6 M sun in M 101 and M . ∼ 6 M sun in NGC 6503. (2) We show that the above galaxies contain only tiny pseudobulges that make up ∼ circ > 150 km s -1 , including M 101, NGC 6946, IC 342, and our Galaxy, show no evidence for a classical bulge. Four may contain small classical bulges that contribute 5%-12% of the light of the galaxy. Only four of the 19 giant galaxies are ellipticals or have classical bulges that contribute ∼1/3 of the galaxy light. We conclude that pure-disk galaxies are far from rare. It is hard to understand how bulgeless galaxies could form as the quiescent tail of a distribution of merger histories. Recognition of pseudobulges makes the biggest problem with cold dark matter galaxy formation more acute: How can hierarchical clustering make so many giant, pure-disk galaxies with no evidence for merger-built bulges? Finally, we emphasize that this problem is a strong function of environment: the Virgo cluster is not a puzzle, because more than 2/3 of its stellar mass is in merger remnants.

  14. Formation of massive clouds and dwarf galaxies during tidal encounters

    Science.gov (United States)

    Kaufman, Michele; Elmegreen, Bruce G.; Thomasson, Magnus; Elmegreen, Debra M.

    1993-01-01

    Gerola et al. (1983) propose that isolated dwarf galaxies can form during galaxy interactions. As evidence of this process, Mirabel et al. (1991) find 10(exp 9) solar mass clouds and star formation complexes at the outer ends of the tidal arms in the Antennae and Superantennae galaxies. We describe observations of HI clouds with mass greater than 10(exp 8) solar mass in the interacting galaxy pair IC 2163/NGC 2207. This pair is important because we believe it represents an early stage in the formation of giant clouds during an encounter. We use a gravitational instability model to explain why the observed clouds are so massive and discuss a two-dimensional N-body simulation of an encounter that produces giant clouds.

  15. Nanometer CMOS ICs from basics to ASICs

    CERN Document Server

    J M Veendrick, Harry

    2017-01-01

    This textbook provides a comprehensive, fully-updated introduction to the essentials of nanometer CMOS integrated circuits. It includes aspects of scaling to even beyond 12nm CMOS technologies and designs. It clearly describes the fundamental CMOS operating principles and presents substantial insight into the various aspects of design implementation and application. Coverage includes all associated disciplines of nanometer CMOS ICs, including physics, lithography, technology, design, memories, VLSI, power consumption, variability, reliability and signal integrity, testing, yield, failure analysis, packaging, scaling trends and road blocks. The text is based upon in-house Philips, NXP Semiconductors, Applied Materials, ASML, IMEC, ST-Ericsson, TSMC, etc., courseware, which, to date, has been completed by more than 4500 engineers working in a large variety of related disciplines: architecture, design, test, fabrication process, packaging, failure analysis and software.

  16. System reduction for nanoscale IC design

    CERN Document Server

    2017-01-01

    This book describes the computational challenges posed by the progression toward nanoscale electronic devices and increasingly short design cycles in the microelectronics industry, and proposes methods of model reduction which facilitate circuit and device simulation for specific tasks in the design cycle. The goal is to develop and compare methods for system reduction in the design of high dimensional nanoelectronic ICs, and to test these methods in the practice of semiconductor development. Six chapters describe the challenges for numerical simulation of nanoelectronic circuits and suggest model reduction methods for constituting equations. These include linear and nonlinear differential equations tailored to circuit equations and drift diffusion equations for semiconductor devices. The performance of these methods is illustrated with numerical experiments using real-world data. Readers will benefit from an up-to-date overview of the latest model reduction methods in computational nanoelectronics.

  17. Clusters of Galaxies

    Science.gov (United States)

    Huchtmeier, W. K.; Richter, O. G.; Materne, J.

    1981-09-01

    The large-scale structure of the universe is dominated by clustering. Most galaxies seem to be members of pairs, groups, clusters, and superclusters. To that degree we are able to recognize a hierarchical structure of the universe. Our local group of galaxies (LG) is centred on two large spiral galaxies: the Andromeda nebula and our own galaxy. Three sr:naller galaxies - like M 33 - and at least 23 dwarf galaxies (KraanKorteweg and Tammann, 1979, Astronomische Nachrichten, 300, 181) can be found in the evironment of these two large galaxies. Neighbouring groups have comparable sizes (about 1 Mpc in extent) and comparable numbers of bright members. Small dwarf galaxies cannot at present be observed at great distances.

  18. Cosmology and galaxy formation

    International Nuclear Information System (INIS)

    Rees, M.J.

    1977-01-01

    Implications of the massive halos and ''missing mass'' for galaxy formation are addressed; it is suggested that this mass consists of ''Population III'' stars that formed before the galaxies did. 19 references

  19. Star-formation rates in the nuclei of violently interacting galaxies

    International Nuclear Information System (INIS)

    Bushouse, H.A.

    1986-01-01

    Spectrophotometry has been obtained of the nuclear regions of a large sample of violently interacting spiral galaxies. The sample galaxies were chosen to include only those systems having tails, plumes, or other morphological features consistent with strong tidal interactions involving disk galaxies. The interacting galaxies are found to exhibit a wide range of nuclear optical emission-line strengths, but show a significantly higher overall level in both Hα emission-line equivalent width and luminosity than samples of field spirals observed in a similar fashion. While galaxy-galaxy interactions can lead to large nuclear star-formation bursts, this is not a ubiquitous phenomenon. A large fraction (approx.30%) of the nuclei show only weak or no detectable optical emission lines and are characterized by stellar absorption spectra of old, elliptical galaxy-like stellar populations, thus indicating little recent or continuing star-formation activity. These circumstances can occur even in instances where the nucleus of the other component has a large population of young stars. While exhaustion of a galaxy's gas supply during the later phases of interaction can account for post-burst systems, it cannot explain systems that have experienced no significant star-formation activity throughout the entire interaction process. Seyfert and low-ionization nuclei also are rare in violently interacting systems which, coupled with the large number of nuclei found to have little star-formation activity, suggests either an initial lack of near-nuclear gas or that gas is present but in inappropriate forms to support star formation or fuel nuclear activity

  20. The discrimination between star-forming and AGN galaxies in the absence of Hαand [NII]: A machine learning approach

    Science.gov (United States)

    Teimoorinia, H.; Keown, J.

    2018-05-01

    In the absence of the two emission lines Hαand [NII] (6584Å) in a BPT diagram, we show that other spectral information is sufficiently informative to distinguish AGN galaxies from star-forming galaxies. We use pattern recognition methods and a sample of galaxy spectra from the Sloan Digital Sky Survey (SDSS) to show that, in this survey, the flux and equivalent width of [OIII] (5007Å) and Hβ, along with the 4000Å break, can be used to classify galaxies in a BPT diagram. This method provides a higher accuracy of predictions than those which use stellar mass and [OIII]/Hβ. First, we use BPT diagrams and various physical parameters to re-classify the galaxies. Next, using confusion matrices, we determine the `correctly' predicted classes as well as confused cases. In this way, we investigate the effect of each parameter in the confusion matrices and rank the physical parameters used in the discrimination of the different classes. We show that in this survey, for example, {g - r} colour can provide the same accuracy as galaxy stellar mass to predict whether or not a galaxy hosts an AGN. Finally, with the same information, we also rank the parameters involved in the discrimination of Seyfert and LINER galaxies.

  1. Sagittarius Dwarf Galaxy

    Science.gov (United States)

    Ibata, R.; Murdin, P.

    2000-11-01

    The Sagittarius DWARF GALAXY is the closest member of the Milky Way's entourage of satellite galaxies. Discovered by chance in 1994, its presence had previously been overlooked because it is largely hidden by the most crowded regions of our own Galaxy with which it is merging....

  2. Tidal interaction of galaxies

    International Nuclear Information System (INIS)

    Kozlov, N.N.; Syunyaev, R.A.; Ehneev, T.M.

    1974-01-01

    One of the hypotheses explaining the occurrence of anomalous details in interacting galaxies has been investigated. Pairs of galaxies with 'tails' oppositely directed or neighbouring galaxies with cofferdams 'bridges', as if connecting the galaxies, are called interacting galaxies. The hypothesis connects the origin of cofferdams and 'tails' of interacting galaxies with tidal effects ; the action of power gravitational forces in the intergalactic space. A source of such forces may be neighbouring stellar systems or invisible bodies, for instance, 'dead' quasars after a gravitational collapse. The effect of large masses of matter on the galaxy evolution has been investigated in the Institute of Applied Mathematics of the Academy of Sciences of the USSSR in 1971-1972 by numerical simulation of the process on a digital computer with the subsequent data transmission on a display. Different versions of a massive body flight relative to a galaxy disk are considered. Photographs of a display screen at different moments of time are presented. As a result of mathematical simulation of galaxies gravitational interactions effects are discovered which resemble real structures in photographs of galaxies. It seems to be premature to state that namely these mechanisms cause the formation of 'tails' and cofferdams between galaxies. However, even now it is clear that the gravitational interaction strongly affects the dynamics of the stellar system evolution. Further studies should ascertain a true scale of this effect and its genuine role in galaxy evolution

  3. Inverse Compton X-Ray Halos Around High-z Radio Galaxies: A Feedback Mechanism Powered by Far-Infrared Starbursts or the Cosmic Microwave Background?

    Science.gov (United States)

    Small, Ian; Blundell, Katherine M.; Lehmer, B. D.; Alexander, D. M.

    2012-01-01

    We report the detection of extended X-ray emission around two powerful radio galaxies at z approx. 3.6 (4C 03.24 and 4C 19.71) and use these to investigate the origin of extended, inverse Compton (IC) powered X-ray halos at high redshifts. The halos have X-ray luminosities of L(sub X) approx. 3 x 10(exp 44) erg/s and sizes of approx.60 kpc. Their morphologies are broadly similar to the approx.60 kpc long radio lobes around these galaxies suggesting they are formed from IC scattering by relativistic electrons in the radio lobes, of either cosmic microwave background (CMB) photons or far-infrared photons from the dust-obscured starbursts in these galaxies. These observations double the number of z > 3 radio galaxies with X-ray-detected IC halos. We compare the IC X-ray-to-radio luminosity ratios for the two new detections to the two previously detected z approx. 3.8 radio galaxies. Given the similar redshifts, we would expect comparable X-ray IC luminosities if millimeter photons from the CMB are the dominant seed field for the IC emission (assuming all four galaxies have similar ages and jet powers). Instead we see that the two z approx. 3.6 radio galaxies, which are 4 fainter in the far-infrared than those at z 3.8, also have approx.4x fainter X-ray IC emission. Including data for a further six z > or approx. 2 radio sources with detected IC X-ray halos from the literature, we suggest that in the more compact, majority of radio sources, those with lobe sizes < or approx.100-200 kpc, the bulk of the IC emission may be driven by scattering of locally produced far-infrared photons from luminous, dust-obscured starbursts within these galaxies, rather than millimeter photons from the CMB. The resulting X-ray emission appears sufficient to ionize the gas on approx.100-200 kpc scales around these systems and thus helps form the extended, kinematically quiescent Ly(alpha) emission line halos found around some of these systems. The starburst and active galactic nucleus

  4. Accretion Properties of a Sample of Hard X-Ray (<60 keV) Selected Seyfert 1 Galaxies

    Science.gov (United States)

    Wang, J.; Mao, Y. F.; Wei, J. Y.

    2009-02-01

    We examine the accretion properties in a sample of 42 hard (3-60 keV) X-ray selected nearby broad-line active galactic nuclei (AGNs). The energy range in the sample is harder than that usually used in similar previous studies. These AGNs are mainly complied from the RXTE All Sky Survey, and complemented by the released INTEGRAL AGN catalog. The black hole masses, bolometric luminosities of AGN, and Eddington ratios are derived from their optical spectra in terms of the broad Hβ emission line. The tight correlation between the hard X-ray (3-20 keV) and bolometric/line luminosity is well identified in our sample. Also identified is a strong inverse Baldwin relationship of the Hβ emission line. In addition, all of these hard X-ray AGNs are biased toward luminous objects with a high Eddington ratio (mostly between 0.01 and 0.1) and a low column density (Simbol-X, and NeXT. Finally, the correlation between RFe (= optical Fe II/Hβ) and disk temperature as assessed by T vprop (L/L Edd)M -1 BH leads us to suggest that the strength of the Fe II emission is mainly determined by the shape of the ionizing spectrum.

  5. Chemical evolution of galaxies

    CERN Document Server

    Matteucci, Francesca

    2012-01-01

    The term “chemical evolution of galaxies” refers to the evolution of abundances of chemical species in galaxies, which is due to nuclear processes occurring in stars and to gas flows into and out of galaxies. This book deals with the chemical evolution of galaxies of all morphological types (ellipticals, spirals and irregulars) and stresses the importance of the star formation histories in determining the properties of stellar populations in different galaxies. The topic is approached in a didactical and logical manner via galaxy evolution models which are compared with observational results obtained in the last two decades: The reader is given an introduction to the concept of chemical abundances and learns about the main stellar populations in our Galaxy as well as about the classification of galaxy types and their main observables. In the core of the book, the construction and solution of chemical evolution models are discussed in detail, followed by descriptions and interpretations of observations of ...

  6. LES of Gas Exchange in IC Engines

    Directory of Open Access Journals (Sweden)

    Mittal V.

    2013-10-01

    Full Text Available As engine technologies become increasingly complex and engines are driven to new operating points, understanding transient phenomena is important to ensure reliable engine operation. Unlike Reynolds Averaged Navier-Stokes (RANS studies that only provide cycle-averaged information, Large Eddy Simulation (LES studies are capable of simulating cycle-to-cycle dynamics. In this work, a finite difference based structured methodology for LES of IC engines is presented. This structured approach allows for an efficient mesh generation process and provides potential for higher order numerical accuracy. An efficient parallel scalable block decomposition is done to overcome the challenges associated with the low ratio of fluid elements to overall mesh elements. The motion of the valves and piston is handled using a dynamic cell blanking approach and the Arbitrary Lagrangian Eulerian (ALE method, respectively. Modified three-dimensional Navier-Stokes Characteristic Boundary Conditions (NSCBC are used in the simulation to prescribe conditions in the manifolds. The accuracy of the simulation framework is validated using various canonical configurations. Flow bench simulations of an axisymmetric configuration and an actual engine geometry are done with the LES methodology. Simulations of the gas exchange in an engine under motored conditions are also performed. Overall, good agreement is obtained with experiments for all the cases. Therefore, this framework can be used for LES of engine simulations. In the future, reactive LES simulations will be performed using this framework.

  7. VizieR Online Data Catalog: Properties of OB associations in IC 1613 (Garcia+, 2010)

    Science.gov (United States)

    Garcia, M.; Herrero, A.; Castro, N.; Corral, L.; Rosenberg, A.

    2014-06-01

    To understand the structure and evolution of massive stars, systematic surveys of the Local Group galaxies have been undertaken, to find these objects in environments of different chemical abundances. We focus on the metal-poor irregular galaxy IC 1613 to analyze the stellar and wind structure of its low-metallicity massive stars. We ultimately aim to study the metallicity-dependent driving mechanism of the winds of blue massive stars and use metal-poor massive stars of the Local Volume as a proxy for the stars in the early Universe. In a previous paper we produced a list of OB associations in IC 1613. Their properties are not only a powerful aid towards finding the most interesting candidate massive stars, but also reveal the structure and recent star formation history of the galaxy. We characterize these OB associations and study their connection with the galactic global properties. The reddening-free Q parameter is a powerful tool in the photometric analysis of young populations of massive stars, since it exhibits a smaller degree of degeneracy with OB spectral types than the B-V color. The color-magnitude diagram (Q vs. V) of the OB associations in IC 1613 is studied to determine their age and mass, and confirm the population of young massive stars. We identified more than 10 stars with M>=50M⊙. Spectral classification available for some of them confirm their massive nature, yet we find the common discrepancy with the spectroscopically derived masses. There is a general increasing trend of the mass of the most massive member with the number of members of each association, but not with the stellar density. The average diameter of the associations of this catalog is 40pc, half the historically considered typical size of OB associations. Size increases with the association population. The distribution of the groups strongly correlates with that of neutral and ionized hydrogen. We find the largest dispersion of association ages in the bubble region of the galaxy

  8. THE STELLAR MASS COMPONENTS OF GALAXIES: COMPARING SEMI-ANALYTICAL MODELS WITH OBSERVATION

    International Nuclear Information System (INIS)

    Liu Lei; Yang Xiaohu; Mo, H. J.; Van den Bosch, Frank C.; Springel, Volker

    2010-01-01

    We compare the stellar masses of central and satellite galaxies predicted by three independent semi-analytical models (SAMs) with observational results obtained from a large galaxy group catalog constructed from the Sloan Digital Sky Survey. In particular, we compare the stellar mass functions of centrals and satellites, the relation between total stellar mass and halo mass, and the conditional stellar mass functions, Φ(M * |M h ), which specify the average number of galaxies of stellar mass M * that reside in a halo of mass M h . The SAMs only predict the correct stellar masses of central galaxies within a limited mass range and all models fail to reproduce the sharp decline of stellar mass with decreasing halo mass observed at the low mass end. In addition, all models over-predict the number of satellite galaxies by roughly a factor of 2. The predicted stellar mass in satellite galaxies can be made to match the data by assuming that a significant fraction of satellite galaxies are tidally stripped and disrupted, giving rise to a population of intra-cluster stars (ICS) in their host halos. However, the amount of ICS thus predicted is too large compared to observation. This suggests that current galaxy formation models still have serious problems in modeling star formation in low-mass halos.

  9. IC 3639—a New Bona Fide Compton-Thick AGN Unveiled by NuSTAR

    Science.gov (United States)

    Boorman, Peter G.; Gandhi, P.; Alexander, D. M.; Annuar, A.; Ballantyne, D. R.; Bauer, F.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Farrah, D.; Hailey, C. J.; Harrison, F. A.; Hönig, S. F.; Koss, M.; LaMassa, S. M.; Masini, A.; Ricci, C.; Risaliti, G.; Stern, D.; Zhang, W. W.

    2016-12-01

    We analyze high-quality NuSTAR observations of the local (z = 0.011) Seyfert 2 active galactic nucleus (AGN) IC 3639, in conjunction with archival Suzaku and Chandra data. This provides the first broadband X-ray spectral analysis of the source, spanning nearly two decades in energy (0.5-30 keV). Previous X-ray observations of the source below 10 keV indicated strong reflection/obscuration on the basis of a pronounced iron fluorescence line at 6.4 keV. The hard X-ray energy coverage of NuSTAR, together with self-consistent toroidal reprocessing models, enables direct broadband constraints on the obscuring column density of the source. We find the source to be heavily Compton-thick (CTK) with an obscuring column in excess of 3.6× {10}24 cm-2, unconstrained at the upper end. We further find an intrinsic 2-10 keV luminosity of {{log}}10({L}2{--10{keV}} [{erg} {{{s}}}-1])={43.4}-1.1+0.6 to 90% confidence, almost 400 times the observed flux, and consistent with various multiwavelength diagnostics. Such a high ratio of intrinsic to observed flux, in addition to an Fe-Kα fluorescence line equivalent width exceeding 2 keV, is extreme among known bona fide CTK AGNs, which we suggest are both due to the high level of obscuration present around IC 3639. Our study demonstrates that broadband spectroscopic modeling with NuSTAR enables large corrections for obscuration to be carried out robustly and emphasizes the need for improved modeling of AGN tori showing intense iron fluorescence.

  10. Galaxy Zoo: dust in spiral galaxies star

    OpenAIRE

    Masters, Karen L.; Nichol, Robert; Bamford, Steven; Mosleh, Moein; Lintott, Chris J.; Andreescu, Dan; Edmondson, Edward M.; Keel, William C.; Murray, Phil; Raddick, M. Jordan; Schawinski, Kevin; Slosar, Anze; Szalay, Alexander S.; Thomas, Daniel; Vandenberg, Jan

    2010-01-01

    We investigate the effect of dust on spiral galaxies by measuring the inclination dependence of optical colours for 24 276 well-resolved Sloan Digital Sky Survey (SDSS) galaxies visually classified via the Galaxy Zoo project. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4 mag for the ugri passbands (estimating 0.3 mag of extinction in z band). We split the sample into ‘bulgy’ (early-type) and ‘discy’ (late-typ...

  11. A close nuclear black-hole pair in the spiral galaxy NGC 3393.

    Science.gov (United States)

    Fabbiano, G; Wang, Junfeng; Elvis, M; Risaliti, G

    2011-08-31

    The current picture of galaxy evolution advocates co-evolution of galaxies and their nuclear massive black holes, through accretion and galactic merging. Pairs of quasars, each with a massive black hole at the centre of its galaxy, have separations of 6,000 to 300,000 light years (refs 2 and 3; 1 parsec = 3.26 light years) and exemplify the first stages of this gravitational interaction. The final stages of the black-hole merging process, through binary black holes and final collapse into a single black hole with gravitational wave emission, are consistent with the sub-light-year separation inferred from the optical spectra and light-variability of two such quasars. The double active nuclei of a few nearby galaxies with disrupted morphology and intense star formation (such as NGC 6240 with a separation of about 2,600 light years and Mrk 463 with a separation of about 13,000 light years between the nuclei) demonstrate the importance of major mergers of equal-mass spiral galaxies in this evolution; such mergers lead to an elliptical galaxy, as in the case of the double-radio-nucleus elliptical galaxy 0402+379 (with a separation of about 24 light years between the nuclei). Minor mergers of a spiral galaxy with a smaller companion should be a more common occurrence, evolving into spiral galaxies with active massive black-hole pairs, but have hitherto not been seen. Here we report the presence of two active massive black holes, separated by about 490 light years, in the Seyfert galaxy NGC 3393 (50 Mpc, about 160 million light years). The regular spiral morphology and predominantly old circum-nuclear stellar population of this galaxy, and the closeness of the black holes embedded in the bulge, provide a hitherto missing observational point to the study of galaxy/black hole evolution. Comparison of our observations with current theoretical models of mergers suggests that they are the result of minor merger evolution. © 2011 Macmillan Publishers Limited. All rights

  12. Infrared and optical polarimetry of the radio elliptical IC 5063 (PKS2048-57): discovery of a highly polarized non-thermal nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Hough, J H; Brindle, C; Axon, D J; Bailey, J; Sparks, W B

    1987-02-15

    Two-aperture optical and near-infrared polarization and flux measurements of the radio elliptical galaxy IC 5063 are presented. Analysis of the polarized flux shows that the large infrared excess in the nucleus most likely arises from a steep-spectrum non-thermal source with a polarization of 17 per cent and near-infrared luminosity 6x10/sup 41/ erg s/sup -1/. This result suggests that IC5063 is closely related to the more luminous blazars. The origin of the polarization in the optical is, however, not clear.

  13. Infrared and optical polarimetry of the radio elliptical IC 5063 (PKS2048-57): discovery of a highly polarized non-thermal nucleus

    International Nuclear Information System (INIS)

    Hough, J.H.; Brindle, C.; Axon, D.J.; Bailey, J.; Sparks, W.B.

    1987-01-01

    Two-aperture optical and near-infrared polarization and flux measurements of the radio elliptical galaxy IC 5063 are presented. Analysis of the polarized flux shows that the large infrared excess in the nucleus most likely arises from a steep-spectrum non-thermal source with a polarization of 17 per cent and near-infrared luminosity 6x10 41 erg s -1 . This result suggests that IC5063 is closely related to the more luminous blazars. The origin of the polarization in the optical is, however, not clear. (author)

  14. Isolated galaxies, pairs, and groups of galaxies

    International Nuclear Information System (INIS)

    Kuneva, I.; Kalinkov, M.

    1990-01-01

    The authors searched for isolated galaxies, pairs and groups of galaxies in the CfA survey (Huchra et al. 1983). It was assumed that the distances to galaxies are given by R = V/H sub o, where H sub o = 100 km s(exp -1) Mpc(exp -1) and R greater than 6 Mpc. The searching procedure is close to those, applied to find superclusters of galaxies (Kalinkov and Kuneva 1985, 1986). A sphere with fixed radius r (asterisk) is described around each galaxy. The mean spatial density in the sphere is m. Let G 1 be any galaxy and G 2 be its nearest neighbor at a distance R 2 . If R sub 2 exceeds the 95 percent quintile in the distribution of the distances of the second neighbors, then G 1 is an isolated galaxy. Let the midpoint of G 1 and G 2 be O 2 and r 2 =R 2 2. For the volume V 2 , defined with the radius r 2 , the density D 2 less than k mu, the galaxy G 2 is a single one and the procedure for searching for pairs and groups, beginning with this object is over and we have to pass to another object. Here the authors present the groups - isolated and nonisolated - with n greater than 3, found in the CfA survey in the Northern galactic hemisphere. The parameters used are k = 10 and r (asterisk) = 5 Mpc. Table 1 contains: (1) the group number, (2) the galaxy, nearest to the multiplet center, (3) multiplicity n, (4) the brightest galaxy if it is not listed in (2); (5) and (6) are R.A. and Dec. (1950), (7) - mean distance D in Mpc. Further there are the mean density rho (8) of the multiplet (galaxies Mpc (exp -3)), (9) the density rho (asterisk) for r (asterisk) = 5 Mpc and (10) the density rho sub g for the group with its nearest neighbor. The parenthesized digits for densities in the last three columns are powers of ten

  15. : Nuclear Spirals and Mass Accretion to Supermassive Black Holes in Weakly-Barred Galaxies

    Science.gov (United States)

    Kim, Woong-Tae; Elmegreen, Bruce

    2018-01-01

    Disk galaxies, especially barred-spiral galaxies, abound with rings and spirals in their nuclear regions. Nuclear spirals existing even in weakly barred galaxies are thought to channel gas inflows to supermassive black holes residing at the centers. We use high-resolution hydrodynamic simulations to study the properties of nuclear gas spirals driven by weak bar-like or oval potentials. The amplitude of the spirals increases toward the center by a geometric effect, readily developing into shocks at small radii even for very weak potentials. The shape of the spirals and shocks depends rather sensitively on the background shear. When shear is low, the nuclear spirals are loosely wound and the shocks are almost straight, resulting in large mass inflows toward the center. When shear is high, on the other hand, the spirals are tightly wound and the shocks are oblique, forming a circumnuclear disk through which gas flows inward at a relatively lower rate. The induced mass inflow rates are enough to power black hole accretion in various types of Seyfert galaxies.

  16. Estimatining biases in the stellar dynamical black hole mass measurements in barred galaxies and prospects for measuring SMBH masses with JWST

    Science.gov (United States)

    Valluri, Monica; Vasiliev, Eugene; Bentz, Misty; Shen, Juntai

    2018-04-01

    Although 60% of disk galaxies are barred, stellar dynamical measurements of the masses of supermassive black holes (SMBH) in barred galaxies have always been obtained under the assumption that the bulges are axisymmetric. We use N-body simulations with self-consistently grown SMBHs in barred and unbarred galaxies to create a suite of mock Integral Field Spectrographic (IFS) datasets for galaxies with various observed orientations. We then apply an axisymmetric orbit superposition code to these mock IFS datasets to assess the reliability with which SMBH masses can be recovered. We also assess which disk and bar orientations give rise to biases. We use these simulations to assess whether or not existing SMBH measurements in barred galaxies are likely to be biased. We also present a brief preview of our JWST Early Release Science proposal to study the nuclear dynamics of nearby Seyfert I galaxy NGC 4151 with the NIRSpec Integral Field Spectrograph and describe how simulations of disk galaxies will used to create mock NIRSpec data to prepare for the real data.

  17. The RSA survey of dwarf galaxies, 1: Optical photometry

    Science.gov (United States)

    Vader, J. Patricia; Chaboyer, Brian

    1994-01-01

    We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r(exp 1/4) law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r(exp 1/4) law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are

  18. Diversity among galaxy clusters

    International Nuclear Information System (INIS)

    Struble, M.F.; Rood, H.J.

    1988-01-01

    The classification of galaxy clusters is discussed. Consideration is given to the classification scheme of Abell (1950's), Zwicky (1950's), Morgan, Matthews, and Schmidt (1964), and Morgan-Bautz (1970). Galaxies can be classified based on morphology, chemical composition, spatial distribution, and motion. The correlation between a galaxy's environment and morphology is examined. The classification scheme of Rood-Sastry (1971), which is based on clusters's morphology and galaxy population, is described. The six types of clusters they define include: (1) a cD-cluster dominated by a single large galaxy, (2) a cluster dominated by a binary, (3) a core-halo cluster, (4) a cluster dominated by several bright galaxies, (5) a cluster appearing flattened, and (6) an irregularly shaped cluster. Attention is also given to the evolution of cluster structures, which is related to initial density and cluster motion

  19. Galaxy formation and evolution

    CERN Document Server

    Mo, Houjun; White, Simon

    2010-01-01

    The rapidly expanding field of galaxy formation lies at the interface between astronomy, particle physics, and cosmology. Covering diverse topics from these disciplines, all of which are needed to understand how galaxies form and evolve, this book is ideal for researchers entering the field. Individual chapters explore the evolution of the Universe as a whole and its particle and radiation content; linear and nonlinear growth of cosmic structure; processes affecting the gaseous and dark matter components of galaxies and their stellar populations; the formation of spiral and elliptical galaxies; central supermassive black holes and the activity associated with them; galaxy interactions; and the intergalactic medium. Emphasizing both observational and theoretical aspects, this book provides a coherent introduction for astronomers, cosmologists, and astroparticle physicists to the broad range of science underlying the formation and evolution of galaxies.

  20. The origin of galaxies

    International Nuclear Information System (INIS)

    Carr, B.J.

    1982-01-01

    The existence of galaxies implies that the early Universe must have contained initial density fluctuations. Overdense regions would then expand more slowly than the background and eventually - providing the fluctuations were not damped out first - they would stop expanding altogether and collapse to form bound objects. To understand how galaxies form we therefore need to know: how the initial density fluctuations arise, under what circumstances they evolve into bound objects, and how the bound objects develop the observed characteristics of galaxies. (author)

  1. Galaxy correlations and cosmology

    International Nuclear Information System (INIS)

    Fall, S.M.

    1979-01-01

    Correlations in the distribution of galaxies provide some important clues about the structure and evolution of the Universe on scales larger than individual galaxies. In recent years much effort has been devoted to estimating and interpreting galaxy correlations. This is a review of these efforts. It is meant to provide both an introductory overview of the subject and a critical assessment of some recent developments

  2. Neighbours of our galaxy

    International Nuclear Information System (INIS)

    Wielebinski, R.

    1982-01-01

    Large telescope and radio-astronomy bring remote regions of the universe into view. Radio waves are emitted by all celestial objects. Precise examination of our own galaxy, the Milky Way, is useful for investigating more remote objects. Some of the remote galaxies are noteworthy, because they emit up to 1,000 times more radio waves than their neighbours. Centaurus A is an example of such an active galaxy. (orig.)

  3. Prometheus Reactor I&C Software Development Methodology, for Action

    Energy Technology Data Exchange (ETDEWEB)

    T. Hamilton

    2005-07-30

    The purpose of this letter is to submit the Reactor Instrumentation and Control (I&C) software life cycle, development methodology, and programming language selections and rationale for project Prometheus to NR for approval. This letter also provides the draft Reactor I&C Software Development Process Manual and Reactor Module Software Development Plan to NR for information.

  4. CORE-COLLAPSE SUPERNOVAE FROM THE PALOMAR TRANSIENT FACTORY: INDICATIONS FOR A DIFFERENT POPULATION IN DWARF GALAXIES

    International Nuclear Information System (INIS)

    Arcavi, Iair; Gal-Yam, Avishay; Kasliwal, Mansi M.; Quimby, Robert M.; Ofek, Eran O.; Kulkarni, Shrinivas R.; Law, Nicholas; Cooke, Jeff; Nugent, Peter E.; Poznanski, Dovi; Cenko, S. Bradley; Bloom, Joshua S.; Filippenko, Alexei V.; Sullivan, Mark; Hook, Isobel; Joensson, Jakob; Blake, Sarah; Howell, D. Andrew; Dekany, Richard; Rahmer, Gustavo

    2010-01-01

    We use the first compilation of 72 core-collapse supernovae (SNe) from the Palomar Transient Factory (PTF) to study their observed subtype distribution in dwarf galaxies compared to giant galaxies. Our sample is the largest single-survey, untargeted, spectroscopically classified, homogeneous collection of core-collapse events ever assembled, spanning a wide host-galaxy luminosity range (down to M r ∼ -14 mag) and including a substantial fraction (>20%) of dwarf (M r ≥ -18 mag) hosts. We find more core-collapse SNe in dwarf galaxies than expected and several interesting trends emerge. We use detailed subclassifications of stripped-envelope core-collapse SNe and find that all Type I core-collapse events occurring in dwarf galaxies are either SNe Ib or broad-lined SNe Ic (SNe Ic-BL), while 'normal' SNe Ic dominate in giant galaxies. We also see a significant excess of SNe IIb in dwarf hosts. We hypothesize that in lower metallicity hosts, metallicity-driven mass loss is reduced, allowing massive stars that would have appeared as 'normal' SNe Ic in metal-rich galaxies to retain some He and H, exploding as Ib/IIb events. At the same time, another mechanism allows some stars to undergo extensive stripping and explode as SNe Ic-BL (and presumably also as long-duration gamma-ray bursts). Our results are still limited by small-number statistics, and our measurements of the observed N(Ib/c)/N(II) number ratio in dwarf and giant hosts (0.25 +0.3 -0.15 and 0.23 +0.11 -0.08 , respectively; 1σ uncertainties) are consistent with previous studies and theoretical predictions. As additional PTF data accumulate, more robust statistical analyses will be possible, allowing the evolution of massive stars to be probed via the dwarf-galaxy SN population.

  5. LONG-TERM X-RAY VARIABILITY STUDY OF IC342 FROM XMM-NEWTON OBSERVATIONS

    International Nuclear Information System (INIS)

    Mak, Daisy S. Y.; Pun, Chun S. J.; Kong, Albert K. H.

    2011-01-01

    We presented the results of an analysis of four XMM-Newton observations of the starburst galaxy IC342 taken over a four-year span from 2001 to 2005, with an emphasis on investigating the long-term flux and spectral variability of the X-ray point sources. We detected a total of 61 X-ray sources within 35' x 30' of the galaxy down to a luminosity of (1-2) x 10 37 erg s -1 depending on the local background. We found that 39 of the 61 detected sources showed long-term variability, in which 26 of them were classified as X-ray transients. We also found 19 sources exhibiting variations in hardness ratios or undergoing spectral transitions among observations, and were identified as spectral variables. In particular, eight of the identified X-ray transients showed spectral variability in addition to flux variability. The diverse patterns of variability observed are indicative of a population of X-ray binaries. We used X-ray colors, flux and spectral variability, and in some cases the optical or radio counterparts to classify the detected X-ray sources into several stellar populations. We identified a total of 11 foreground stars, 1 supersoft source (SSS), 3 quasisoft sources (QSSs), and 2 supernova remnants (SNRs). The identified SSS/QSSs are located near or on the spiral arms, associated with young stellar populations; the 2 SNRs are very close to the starburst nucleus where current star formation activities are dominated. We also discovered a spectral change in the nuclear source of IC342 for the first time by a series of X-ray spectrum analysis.

  6. Galaxy Zoo: dust in spiral galaxies

    Science.gov (United States)

    Masters, Karen L.; Nichol, Robert; Bamford, Steven; Mosleh, Moein; Lintott, Chris J.; Andreescu, Dan; Edmondson, Edward M.; Keel, William C.; Murray, Phil; Raddick, M. Jordan; Schawinski, Kevin; Slosar, Anže; Szalay, Alexander S.; Thomas, Daniel; Vandenberg, Jan

    2010-05-01

    We investigate the effect of dust on spiral galaxies by measuring the inclination dependence of optical colours for 24276 well-resolved Sloan Digital Sky Survey (SDSS) galaxies visually classified via the Galaxy Zoo project. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4mag for the ugri passbands (estimating 0.3mag of extinction in z band). We split the sample into `bulgy' (early-type) and `discy' (late-type) spirals using the SDSS fracdeV (or fDeV) parameter and show that the average face-on colour of `bulgy' spirals is redder than the average edge-on colour of `discy' spirals. This shows that the observed optical colour of a spiral galaxy is determined almost equally by the spiral type (via the bulge-disc ratio and stellar populations), and reddening due to dust. We find that both luminosity and spiral type affect the total amount of extinction, with discy spirals at Mr ~ -21.5mag having the most reddening - more than twice as much as both the lowest luminosity and most massive, bulge-dominated spirals. An increase in dust content is well known for more luminous galaxies, but the decrease of the trend for the most luminous has not been observed before and may be related to their lower levels of recent star formation. We compare our results with the latest dust attenuation models of Tuffs et al. We find that the model reproduces the observed trends reasonably well but overpredicts the amount of u-band attenuation in edge-on galaxies. This could be an inadequacy in the Milky Way extinction law (when applied to external galaxies), but more likely indicates the need for a wider range of dust-star geometries. We end by discussing the effects of dust on large galaxy surveys and emphasize that these effects will become important as we push to higher precision measurements of galaxy properties and their clustering. This publication has been made possible by the participation of more than

  7. Interrogating Seyferts with NebulaBayes: Spatially Probing the Narrow-line Region Radiation Fields and Chemical Abundances

    Science.gov (United States)

    Thomas, Adam D.; Dopita, Michael A.; Kewley, Lisa J.; Groves, Brent A.; Sutherland, Ralph S.; Hopkins, Andrew M.; Blanc, Guillermo A.

    2018-04-01

    NebulaBayes is a new Bayesian code that implements a general method of comparing observed emission-line fluxes to photoionization model grids. The code enables us to extract robust, spatially resolved measurements of abundances in the extended narrow-line regions (ENLRs) produced by Active Galactic Nuclei (AGN). We observe near-constant ionization parameters but steeply radially declining pressures, which together imply that radiation pressure regulates the ENLR density structure on large scales. Our sample includes four “pure Seyfert” galaxies from the S7 survey that have extensive ENLRs. NGC 2992 shows steep metallicity gradients from the nucleus into the ionization cones. An inverse metallicity gradient is observed in ESO 138-G01, which we attribute to a recent gas inflow or minor merger. A uniformly high metallicity and hard ionizing continuum are inferred across the ENLR of Mrk 573. Our analysis of IC 5063 is likely affected by contamination from shock excitation, which appears to soften the inferred ionizing spectrum. The peak of the ionizing continuum E peak is determined by the nuclear spectrum and the absorbing column between the nucleus and the ionized nebula. We cannot separate variation in this intrinsic E peak from the effects of shock or H II region contamination, but E peak measurements nevertheless give insights into ENLR excitation. We demonstrate the general applicability of NebulaBayes by analyzing a nuclear spectrum from the non-active galaxy NGC 4691 using a H II region grid. The NLR and H II region model grids are provided with NebulaBayes for use by the astronomical community.

  8. Broad Line Radio Galaxies Observed with Fermi-LAT: The Origin of the GeV Gamma-Ray Emission

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, J.; /Waseda U., RISE; Stawarz, L.; /JAXA, Sagamihara /Jagiellonian U., Astron. Observ.; Takahashi, Y.; /Waseda U., RISE; Cheung, C.C.; /Natl. Acad. Sci. /Naval Research Lab, Wash., D.C.; Hayashida, M.; /SLAC /Stanford U., HEPL /KIPAC, Menlo Park; Grandi, P.; /Bologna Observ.; Burnett, T.H.; /Washington U., Seattle; Celotti, A.; /SISSA, Trieste; Fegan, S.J.; Fortin, P.; /Ecole Polytechnique; Maeda, K.; Nakamori, T.; /Waseda U., RISE; Taylor, G.B.; /New Mexico U.; Tosti, G.; /INFN, Perugia /Perugia U.; Digel, S.W.; /SLAC /Stanford U., HEPL /KIPAC, Menlo Park; McConville, W.; /NASA, Goddard /Maryland U.; Finke, J.; /Naval Research Lab, Wash., D.C.; D' Ammando, F.; /IASF, Palermo /INAF, Rome

    2012-06-07

    We report on a detailed investigation of the {gamma}-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the GeV photon energy range; a detailed look at the temporal characteristics of the observed {gamma}-ray emission reveals in addition possible flux variability in both sources. No statistically significant {gamma}-ray detection of the other BLRGs was however found in the considered dataset. Though the sample size studied is small, what appears to differentiate 3C 111 and 3C 120 from the BLRGs not yet detected in {gamma}-rays is the particularly strong nuclear radio flux. This finding, together with the indications of the {gamma}-ray flux variability and a number of other arguments presented, indicate that the GeV emission of BLRGs is most likely dominated by the beamed radiation of relativistic jets observed at intermediate viewing angles. In this paper we also analyzed a comparison sample of high accretion-rate Seyfert 1 galaxies, which can be considered radio-quiet counterparts of BLRGs, and found none were detected in {gamma}-rays. A simple phenomenological hybrid model applied for the broad-band emission of the discussed radio-loud and radio-quiet type 1 active galaxies suggests that the relative contribution of the nuclear jets to the accreting matter is {ge} 1% on average for BLRGs, while {le} 0.1% for Seyfert 1 galaxies.

  9. Gemini NIFS survey of feeding and feedback processes in nearby active galaxies - II. The sample and surface mass density profiles

    Science.gov (United States)

    Riffel, R. A.; Storchi-Bergmann, T.; Riffel, R.; Davies, R.; Bianchin, M.; Diniz, M. R.; Schönell, A. J.; Burtscher, L.; Crenshaw, M.; Fischer, T. C.; Dahmer-Hahn, L. G.; Dametto, N. Z.; Rosario, D.

    2018-02-01

    We present and characterize a sample of 20 nearby Seyfert galaxies selected for having BAT 14-195 keV luminosities LX ≥ 1041.5 erg s-1, redshift z ≤ 0.015, being accessible for observations with the Gemini Near-Infrared Field Spectrograph (NIFS) and showing extended [O III]λ5007 emission. Our goal is to study Active Galactic Nucleus (AGN) feeding and feedback processes from near-infrared integral-field spectra, which include both ionized (H II) and hot molecular (H2) emission. This sample is complemented by other nine Seyfert galaxies previously observed with NIFS. We show that the host galaxy properties (absolute magnitudes MB, MH, central stellar velocity dispersion and axial ratio) show a similar distribution to those of the 69 BAT AGN. For the 20 galaxies already observed, we present surface mass density (Σ) profiles for H II and H2 in their inner ˜500 pc, showing that H II emission presents a steeper radial gradient than H2. This can be attributed to the different excitation mechanisms: ionization by AGN radiation for H II and heating by X-rays for H2. The mean surface mass densities are in the range (0.2 ≤ ΣH II ≤ 35.9) M⊙ pc-2, and (0.2 ≤ ΣH2 ≤ 13.9)× 10-3 M⊙ pc-2, while the ratios between the H II and H2 masses range between ˜200 and 8000. The sample presented here will be used in future papers to map AGN gas excitation and kinematics, providing a census of the mass inflow and outflow rates and power as well as their relation with the AGN luminosity.

  10. The radio halo and active galaxies in the Coma cluster

    International Nuclear Information System (INIS)

    Cordey, R.A.

    1985-01-01

    The Cambridge Low-Frequency Synthesis Telescope has been used to map the Coma cluster at 151 MHz. Two new extended sources are found, associated with the cluster galaxies NGC4839 and NGC4849. The central halo radio source is shown not to have a simple symmetrical structure but to be distorted, with separate centres of brightening near the radio galaxies NGC4874 and IC4040. The structure cannot be accounted for by cluster-wide acceleration processes but implies a close connection with current radio galaxies and, in particular, models requiring diffusion of electrons out of radio sources seem to be favoured. The other large source, near Coma A, is detected and higher resolution data at 1407 MHz are used to clarify its structure. (author)

  11. A MAGELLAN-IMACS-IFU SEARCH FOR DYNAMICAL DRIVERS OF NUCLEAR ACTIVITY. I. REDUCTION PIPELINE AND GALAXY CATALOG

    International Nuclear Information System (INIS)

    Westoby, P. B.; Mundell, C. G.; Maciejewski, W.; Baldry, I. K.; Nagar, N. M.; Emsellem, E.; Roth, M. M.; Gerssen, J.

    2012-01-01

    Using the IMACS integral-field unit (IFU) on the 6.5 m Magellan telescope, we have designed the first statistically significant investigation of the two-dimensional distribution and kinematics of ionized gas and stars in the central kiloparsec regions of a well-matched sample of Seyfert and inactive control galaxies selected from the Sloan Digital Sky Survey. The goals of the project are to use the fine spatial sampling (0.2 arcsec pixel –1 ) and large wavelength coverage (4000-7000 Å) of the IMACS-IFU to search for dynamical triggers of nuclear activity in the central region where active galactic nucleus (AGN) activity and dynamical timescales become comparable, to identify and assess the impact of AGN-driven outflows on the host galaxy and to provide a definitive sample of local galaxy kinematics for comparison with future three-dimensional kinematic studies of high-redshift systems. In this paper, we provide the first detailed description of the procedure to reduce and calibrate data from the IMACS-IFU in 'long mode' to obtain two-dimensional maps of the distribution and kinematics of ionized gas and stars. The sample selection criteria are presented, the observing strategy is described, and resulting maps of the sample galaxies are presented along with a description of the observed properties of each galaxy and the overall observed properties of the sample.

  12. The Carnegie Hubble Program: The Infrared Leavitt Law in IC 1613

    Science.gov (United States)

    Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Monson, Andrew J.; Persson, S. E.; Seibert, Mark; Rigby, Jane R.; Melbourne, Jason

    2013-01-01

    We have observed the dwarf galaxy IC 1613 at multiple epochs in the midinfrared using Spitzer and the in the near-infrared using the new FourStar near-IR camera on Magellan. We have constructed Cepheid period luminosity relations in the J, H, Ks, [3.6] and [4.5] bands and have used the run of their apparent distance moduli as a function of wavelength to derive the line of sight reddening and distance to IC 1613. Using a nineband fit, we find E(BV ) = 0.050.01 mag and an extinction corrected distance modulus of 0 = 24.29 0.03statistical 0.03systematic mag. By comparing our multiband and [3.6] distance moduli to results from the tip of the red giant branch and red clump distance indicators, we find that metallicity has no measurable effect on Cepheid distances at 3.6 m in the metallicity range 1.0 [Fe/H] 0.2, hence derivations of the Hubble constant at this wavelength require no correction for metallicity.

  13. The Implications Related to Different IC, Different Projects and Different Thinking Addressing the Common Core of IC

    DEFF Research Database (Denmark)

    Lindgren, Peter; Saghaug, Kristin Margrethe

    2009-01-01

    challenge the development of IC: - The IC at the organizational level seems to diminish when innovation gets highly dispersed and is operated outside the core of the organization - The attractiveness of the organization to different ICA, which is one fundament to sustainable and successful innovation, seems...... to fall when the IC at the organizational core level diminishes The objective of this paper is therefore to understand 1) How the IC at the organizational core level may continue to be developed, when at the same time innovation is taking place in dispersed groups and projects. 2) How to motivate...... the different ICA´s to bring learning and knowledge back to the core with the purpose to develop IC at the organizational core level....

  14. The formation of galaxies

    International Nuclear Information System (INIS)

    Gunn, J.E.

    1983-01-01

    The presently fashionable ideas for galaxy formation are reviewed briefly, and it is concluded that the standard isothermal heirarchy fits the available data best. A simple infall picture is presented which explains many of the observed properties of disk galaxies. (orig.)

  15. The galaxy builders

    Science.gov (United States)

    Cho, Adrian

    2018-06-01

    Philip Hopkins, a theoretical astrophysicist at the California Institute of Technology in Pasadena, likes to prank his colleagues. An expert in simulating the formation of galaxies, Hopkins sometimes begins his talks by projecting images of his creations next to photos of real galaxies and defying his audience to tell them apart. "We can even trick astronomers," Hopkins says. For decades, scientists have tried to simulate how the trillions of galaxies in the observable universe arose from clouds of gas after the big bang. But only in the past few years have the simulations begun to reproduce both the details of individual galaxies and their distribution of masses and shapes. As the fake universes improve, their role is also changing. Previously, information flowed one way: from the astronomers studying real galaxies to the modelers trying to simulate them. Now, insight is flowing the other way, too, with the models helping guide astronomers and astrophysicists. The models suggest that the earliest galaxies were oddly pickle-shaped, that wafer-thin spiral galaxies are surprisingly rugged in the face of collisions, and, perhaps most important, that galaxies must form stars far more slowly than astrophysicists expected. Progress is coming so fast, says Tiziana Di Matteo, a numerical cosmologist at Carnegie Mellon University in Pittsburgh, Pennsylvania, that "the whole thing has reached this little golden age."

  16. The Evolution of Galaxies

    Czech Academy of Sciences Publication Activity Database

    Palouš, Jan

    2007-01-01

    Roč. 17, - (2007), s. 34-40 ISSN 1220-5168. [Heliospere and galaxy. Sinaia, 03.05.2007-05.05.2007] R&D Projects: GA MŠk(CZ) LC06014 Institutional research plan: CEZ:AV0Z10030501 Keywords : ISM structure * stars formation * evolution of galaxies Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  17. Dwarf Elliptical Galaxies

    Science.gov (United States)

    Caldwell, N.; Murdin, P.

    2000-11-01

    DWARF SPHEROIDAL GALAXIES were first identified by Shapley, who had noticed two very diffuse collections of stars on Harvard patrol plates. Although these systems had about as many stars as a GLOBULAR CLUSTER, they were of much lower density, and hence much larger radius, and thus were considered distinct galaxies. These two, named Fornax and Sculptor after the constellations in which they ap...

  18. Hubble's Menagerie of Galaxies

    Indian Academy of Sciences (India)

    Srimath

    astronom ers have even w ondered ifH ubble's galaxy typ es form an evolutionary sequence: does one type of galaxy evolve into another? 1. T he D iscovery of G alaxies. A stronom ers began to ponder these issues only after they discovered w hat ...

  19. Our galaxy is exploding

    International Nuclear Information System (INIS)

    Closets, Francois de.

    1977-01-01

    Improvements made in radioastronomy, and infrared, X and γ emission studies of the Galaxy have allowed to study the galactic nucleus, which is characterized by an intense activity. The most recent hypotheses made to explain this activity and replace it in the general context of the evolution of the galaxies are presented [fr

  20. Our aging galaxy

    International Nuclear Information System (INIS)

    Lyngaa, G.

    1980-01-01

    The origin and evolution of the galaxies is described, according to the presently prevailing theories. The various types of galaxy and their structures are described, and also the formation of stars from the gas clouds. The spiral structure and the evolution of the disc are discussed. Finally the future development on the time scale of thousands of millions of years is briefly discussed. (JIW)

  1. Visibility of galaxies

    International Nuclear Information System (INIS)

    Disney, M.J.

    1976-01-01

    It is stated that counts of galaxies could be seriously biased by selection effects, largely influenced by the brightness of the night sky. To illustrate this suppose the Earth were situated near the center of a giant elliptical galaxy. The mean surface brightness of the sky would then appear some 8 to 9 mag. brighter than is observed from our position in the Galaxy. Extragalactic space would then appear to be empty void; spiral and irregular galaxies would be invisible, and all that could be easily detected would be the core regions of galaxy ellipticals very similar to our own. Much of the Universe would be blinded by the surface brightness of the parent galaxy. This blinding, however, is a relative matter and the question arises as to what extent we are blinded by the spiral galaxy in which we exist. Strong indirect evidence exists that our knowledge of galaxies is heavily biased by the sky background, and the true population of extragalactic space may be very different from that seen. Other relevant work is also discussed, and further investigational work is indicated. (U.K.)

  2. Distant Galaxy Clusters Hosting Extreme Central Galaxies

    Science.gov (United States)

    McDonald, Michael

    2014-09-01

    The recently-discovered Phoenix cluster harbors the most star-forming central cluster galaxy of any cluster in the known Universe, by nearly a factor of 10. This extreme system appears to be fulfilling early cooling flow predictions, although the lack of similar systems makes any interpretation difficult. In an attempt to find other "Phoenix-like" clusters, we have cross-correlated archival all-sky surveys (in which Phoenix was detected) and isolated 4 similarly-extreme systems which are also coincident in position and redshift with an overdensity of red galaxies. We propose here to obtain Chandra observations of these extreme, Phoenix-like systems, in order to confirm them as relaxed, rapidly-cooling galaxy clusters.

  3. Supergalactic studies. I. Supergalactic distribution of the nearest galaxies

    International Nuclear Information System (INIS)

    de Vaucouleurs, G.

    1975-01-01

    The supergalactic distribution of the nearest galaxies is investigated to test the nature of the Local Supercluster and to determine whether the Local Group is inside or outside its boundaries. Objectively selected samples of galaxies generally nearer than 10 Mpc are defined by members of the Local Group, the largest and/or brightest galaxies (mag 10', with V 0 -1 ), low-velocity galaxies (V 0 -1 ), the DDO dwarfs. The great majority of these objects are distributed in a broad belt well populated in both hemispheres and inclined 14degree to the supergalactic equator. This belt, including the Local Group, the Sculptor ring, the Centaurus chain, the M51, M81, M101, and IC 342 groups, and several others as well as isolated, nearby field galaxies, is a supergalactic analog to the Gould belt in galactic structure. Its north pole is at L=172degree, B=+76degree, and there is a small dip of about -4degree indicating that the Galaxy is approx.0.3 Mpc to the north of the equatorial plane of this Local Cloud of galaxies. The nearby intergalactic H i clouds, and in particular the Magellanic Stream, are also close to the same plane. The probability that the observed distributions could arise by chance if nearby groups and galaxies were randomly distributed is in the range P -3 to P -5 for the varous classes of objects. It is concluded that the Local Supercluster is a disklike physical and dynamical system, and the Local Group is well within the borders of the system. The alternative hypothesis that it is an appearance resulting from a random clumping accident has negligibly small probability

  4. Starbursts and IRAS galaxies

    International Nuclear Information System (INIS)

    Belfort, P.

    1987-01-01

    Several observational hints suggest that most of the IRAS galaxies are undergoing bursts of star formation. A simple photometric model of starburst galaxy was developed in order to check whether starburst events are really able to account for the far-infrared and optical properties of all the IRAS galaxies with HII region-like spectra. FIR activities up to a few hundred are actually easily reached with rather small bursts in red host-galaxies, and L IR /L B , EW(Hα) and U-B) versus (B-V) diagrams can be used to estimate burst strength and extinction. But more observations are required to conclude about the most extreme cases. Four typical infrared-selected IRAS galaxies are presented and their burst strength and extinction estimated

  5. MULTIPLE GALAXY COLLISIONS

    Science.gov (United States)

    2002-01-01

    Here is a sampling of 15 ultraluminous infrared galaxies viewed by NASA's Hubble Space Telescope. Hubble's sharp vision reveals more complexity within these galaxies, which astronomers are interpreting as evidence of a multiple-galaxy pileup. These images, taken by the Wide Field and Planetary Camera 2, are part of a three-year study of 123 galaxies within 3 billion light-years of Earth. The study was conducted in 1996, 1997, and 1999. False colors were assigned to these photos to enhance fine details within these coalescing galaxies. Credits: NASA, Kirk Borne (Raytheon and NASA Goddard Space Flight Center, Greenbelt, Md.), Luis Colina (Instituto de Fisica de Cantabria, Spain), and Howard Bushouse and Ray Lucas (Space Telescope Science Institute, Baltimore, Md.)

  6. Gas accretion onto galaxies

    CERN Document Server

    Davé, Romeel

    2017-01-01

    This edited volume presents the current state of gas accretion studies from both observational and theoretical perspectives, and charts our progress towards answering the fundamental yet elusive question of how galaxies get their gas. Understanding how galaxies form and evolve has been a central focus in astronomy for over a century. These studies have accelerated in the new millennium, driven by two key advances: the establishment of a firm concordance cosmological model that provides the backbone on which galaxies form and grow, and the recognition that galaxies grow not in isolation but within a “cosmic ecosystem” that includes the vast reservoir of gas filling intergalactic space. This latter aspect in which galaxies continually exchange matter with the intergalactic medium via inflows and outflows has been dubbed the “baryon cycle”. The topic of this book is directly related to the baryon cycle, in particular its least well constrained aspect, namely gas accretion. Accretion is a rare area of ast...

  7. Spectral evolution of galaxies

    International Nuclear Information System (INIS)

    Rocca-Volmerange, B.

    1989-01-01

    A recent striking event in Observational Cosmology is the discovery of a large population of galaxies at extreme cosmological distances (extended from spectral redshifts ≅ 1 to ≥ 3) corresponding to a lookback time of 80% of the Universe's age. However when galaxies are observed at such remote epochs, their appearances are affected by at least two simultaneous effects which are respectively a cosmological effect and the intrinsic evolution of their stellar populations which appear younger than in our nearby galaxies. The fundamental problem is first to disentangle the respective contributions of these two effects to apparent magnitudes and colors of distant galaxies. Other effects which are likely to modify the appearance of galaxies are amplification by gravitational lensing and interaction with environment will also be considered. (author)

  8. População estelar nuclear e extranuclear em galáxias Seyfert 2

    Science.gov (United States)

    Raimann, D. I.; Storchi-Bergmann, T.; Cid Fernandes, R., Jr.; Delgado, R. M. G.; Schmitt, H.; Heckman, T.; Leitherer, C.

    2003-08-01

    A luz das estrelas foi, historicamente, vista por observadores de AGNs como uma poluição inconveniente. Conseqüentemente, a informação contida nas características estelares foi, durante muito tempo, largamente omitida. Nos primeiros estudos, o método empregado para remover esta contaminação estelar foi representá-la por um template de galáxia elíptica e subtraí-la do espectro observado, restando o puro AGN como um resíduo. Hoje sabemos que não é tão simples representar essa população. Vários estudos têm mostrado a presença de formação estelar recente próxima a região nuclear de galáxias Seyfert. Neste trabalho foi revisada a abordagem tradicional, tendo-se focalizado a análise na luz estelar. Espectros óticos de fenda longa, com alta razão sinal/ruído, foram usados para estudar a variação radial das larguras equivalentes de linhas de absorção e cores do contínuo. Utilizando o método de síntese espectral de populações estelares, foram estimadas as contribuições de populações estelares de diferentes idades (e de um contínuo tipo lei de potência) para a luz integrada das galáxias, em 4020A. As principais conclusões deste trabalho são: na região nuclear, mais da metade das galáxias Seyfert 2 da amostra (57%) apresenta contribuições das populações com 100 milhões de anos ou mais jovens superior a 20% do fluxo em 4020A, enquanto que em cerca de 40% delas a componente de 3 milhões de anos (e/ou luz que provem de um núcleo ativo) tem contribuição significativa (maior do que 10%). Estas contribuições em geral decrescem quando se vai para regiões mais distantes do centro das galáxias, respectivamente 53% e 30% a 1kpc, 40% e 15% a 3kpc do centro das galáxias. Estes resultados foram comparados com aqueles obtidos para uma amostra de galáxias não ativas de mesmo tipo de Hubble das Seyfert. Em uma análise inicial nota-se que em geral as galáxias Seyfert apresentam contribuições das populações de 100 milh

  9. Low-ionization galaxies and evolution in a pilot survey up to z = 1

    International Nuclear Information System (INIS)

    Giraud, Edmond; Gu Qiusheng; Melnick, Jorge; Selman, Fernando; Quintana, Hernan; Toledo, Ignacio; Zelaya, Paula

    2011-01-01

    We present galactic spectroscopic data from a pencil beam of 10.75' x 7.5' centered on the X-ray cluster RXJ0054.0-2823 at z = 0.29. We study the spectral evolution of galaxies from z = 1 down to the cluster redshift in a magnitude-limited sample at R ≤ 23, for which the statistical properties of the sample are well understood. We divide emission-line galaxies into star-forming galaxies, Low Ionization Nuclear Emission line Regions (LINERs), and Seyferts by using emission-line ratios of [OII], Hβ, and [OIII], and derive stellar fractions from population synthesis models. We focus our analysis on absorption and low-ionization galaxies. For absorption-line galaxies, we recover the well-known result that these galaxies have had no detectable evolution since z ∼ 0.6 - 0.7, but we also find that in the range z = 0.65 - 1, at least 50% of the stars in bright absorption systems are younger than 2.5 Gyr Faint absorption-line galaxies in the cluster at z = 0.29 also had significant star formation during the previous 2 - 3 Gyr, but their brighter counterparts seem to be only composed of old stars. At z ∼ 0.8, our dynamically young cluster had a truncated red-sequence. This result seems to be consistent with a scenario where the final assembly of E/S0 took place at z < 1. In the volume-limited range 0.35 ≤ z ≤ 0.65, we find that 23% of the early-type galaxies have LINER-like spectra with Hβ in absorption and have a significant component of A stars. The vast majority of LINERs in our sample have significant populations of young and intermediate-aged stars and are thus not related to AGNs, but to the population of 'retired galaxies' recently identified by Cid Fernandes et al. in the Sloan Digital Sky Survey (SDSS). Early-type LINERs with various fractions of A stars and E+A galaxies appear to play an important role in the formation of the red sequence.

  10. The galaxy ancestor problem

    Science.gov (United States)

    Disney, M. J.; Lang, R. H.

    2012-11-01

    The Hubble Space Telescope (HST) findsgalaxies whose Tolman dimming exceeds 10 mag. Could evolution alone explain these as our ancestor galaxies or could they be representatives of quite a different dynasty whose descendants are no longer prominent today? We explore the latter hypothesis and argue that surface brightness selection effects naturally bring into focus quite different dynasties from different redshifts. Thus, the HST z = 7 galaxies could be examples of galaxies whose descendants are both too small and too choked with dust to be recognizable in our neighbourhood easily today. Conversely, the ancestors of the Milky Way and its obvious neighbours would have completely sunk below the sky at z > 1.2, unless they were more luminous in the past, although their diffused light could account for the missing re-ionization flux. This Succeeding Prominent Dynasties Hypothesis (SPDH) fits the existing observations both naturally and well even without evolution, including the bizarre distributions of galaxy surface brightness found in deep fields, the angular size ˜(1 + z)-1 law, 'downsizing' which turns out to be an 'illusion' in the sense that it does not imply evolution, 'infant mortality', that is, the discrepancy between stars born and stars seen, the existence of 'red nuggets', and finally the recently discovered and unexpected excess of quasar absorption line damped Lyα systems at high redshift. If galaxies were not significantly brighter in the past and the SPDH were true, then a large proportion of galaxies could remain sunk from sight, possibly at all redshifts, and these sunken galaxies could supply the missing re-ionization flux. We show that fishing these sunken galaxies out of the sky by their optical emissions alone is practically impossible, even when they are nearby. More ingenious methods are needed to detect them. It follows that disentangling galaxy evolution through studying ever higher redshift galaxies may be a forlorn hope because one could

  11. Are spiral galaxies heavy smokers?

    International Nuclear Information System (INIS)

    Davies, J.; Disney, M.; Phillipps, S

    1990-01-01

    The dustiness of spiral galaxies is discussed. Starburst galaxies and the shortage of truly bright spiral galaxies is cited as evidence that spiral galaxies are far dustier than has been thought. The possibility is considered that the dust may be hiding missing mass

  12. Virtual design and qualification of IC backend structures

    NARCIS (Netherlands)

    Silfhout, van R.B.R.; Sluis, van der O.; Driel, van W.D.; Janssen, J.H.J.; Zhang, G.Q.

    2006-01-01

    For Integrated Circuit (IC) wafer backend development, process developers have to design robust backend structures that guarantee both functionality and reliability during waferfab processes, packaging, qualification tests and lifetime. Figure 1 shows a simplified diagram for the design (and

  13. Interband cascade (IC) photovoltaic (PV) architecture for PV devices

    Science.gov (United States)

    Yang, Rui Q.; Tian, Zhaobing; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Klem, John F.

    2015-10-20

    A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

  14. Study on Mine Emergency Mechanism based on TARP and ICS

    Science.gov (United States)

    Xi, Jian; Wu, Zongzhi

    2018-01-01

    By analyzing the experiences and practices of mine emergency in China and abroad, especially the United States and Australia, normative principle, risk management principle and adaptability principle of constructing mine emergency mechanism based on Trigger Action Response Plans (TARP) and Incident Command System (ICS) are summarized. Classification method, framework, flow and subject of TARP and ICS which are suitable for the actual situation of domestic mine emergency are proposed. The system dynamics model of TARP and ICS is established. The parameters such as evacuation ratio, response rate, per capita emergency capability and entry rate of rescuers are set up. By simulating the operation process of TARP and ICS, the impact of these parameters on the emergency process are analyzed, which could provide a reference and basis for building emergency capacity, formulating emergency plans and setting up action plans in the emergency process.

  15. APPLICATTON OF SCTENTIF'IC PRINCIPLES IN MERINO SHEEP ...

    African Journals Online (AJOL)

    THE PRACTICAI- APPLICATTON OF SCTENTIF'IC PRINCIPLES IN MERINO SHEEP BREEDING. C.A. van der ..... There is, however, no practical evidence in this ... 1910" Comparison of three Australian merino strains for wool and body traits.

  16. Simulation of design dependent failure exposure levels for CMOS ICs

    International Nuclear Information System (INIS)

    Kaul, N.; Bhuva, B.L.; Rangavajjhala, V.; van der Molen, H.; Kerns, S.E.

    1990-01-01

    The total dose exposure of CMOS ICs introduces bias-dependent parameter shifts in individual devices. The bias dependency of individual parameter shifts of devices cause different designs to behave differently under identical testing conditions. This paper studies the effect of design and bias on the radiation tolerance of ICs and presents an automated design tool that produces different designs for a logic function, and presents important parameters of each design to circuit designer for trade off analysis

  17. Rebuilding Spiral Galaxies

    Science.gov (United States)

    2005-01-01

    Major Observing Programme Leads to New Theory of Galaxy Formation Summary Most present-day large galaxies are spirals, presenting a disc surrounding a central bulge. Famous examples are our own Milky Way or the Andromeda Galaxy. When and how did these spiral galaxies form? Why do a great majority of them present a massive central bulge? An international team of astronomers [1] presents new convincing answers to these fundamental questions. For this, they rely on an extensive dataset of observations of galaxies taken with several space- and ground-based telescopes. In particular, they used over a two-year period, several instruments on ESO's Very Large Telescope. Among others, their observations reveal that roughly half of the present-day stars were formed in the period between 8,000 million and 4,000 million years ago, mostly in episodic burst of intense star formation occurring in Luminous Infrared Galaxies. From this and other evidence, the astronomers devised an innovative scenario, dubbed the "spiral rebuilding". They claim that most present-day spiral galaxies are the results of one or several merger events. If confirmed, this new scenario could revolutionise the way astronomers think galaxies formed. PR Photo 02a/05: Luminosity - Oxygen Abundance Relation for Galaxies (VLT) PR Photo 02b/05: The Spiral Rebuilding Scenario A fleet of instruments How and when did galaxies form? How and when did stars form in these island universes? These questions are still posing a considerable challenge to present-day astronomers. Front-line observational results obtained with a fleet of ground- and space-based telescopes by an international team of astronomers [1] provide new insights into these fundamental issues. For this, they embarked on an ambitious long-term study at various wavelengths of 195 galaxies with a redshift [2] greater than 0.4, i.e. located more than 4000 million light-years away. These galaxies were studied using ESO's Very Large Telescope, as well as the

  18. Dwarf galaxies : Important clues to galaxy formation

    NARCIS (Netherlands)

    Tolstoy, E

    2003-01-01

    The smallest dwarf galaxies are the most straight forward objects in which to study star formation processes on a galactic scale. They are typically single cell star forming entities, and as small potentials in orbit around a much larger one they are unlikely to accrete much (if any) extraneous

  19. Superclusters and galaxy formation

    Energy Technology Data Exchange (ETDEWEB)

    Einasto, J; Joeveer, M; Saar, E [Tartu Astrophysical Observatory, Toravere, Estonia (USSR)

    1980-01-03

    A study of the structure of superclusters in the Southern galactic hemisphere using Zwicky clusters as principal tracers of the large-scale structure of the Universe is reported. The data presented suggest that the formation of galaxies was a two stage process involving larger spatial dimensions than earlier workers have postulated. In the first stage proto-superclusters and big holes had to form from the non-dissipative dark matter while in the second hot gas, by cooling and settling down into the potential wells caused by dark matter, will form galaxies and clusters of galaxies.

  20. Water saving in IC wafer washing process; IC wafer senjo deno sessui taisaku

    Energy Technology Data Exchange (ETDEWEB)

    Harada, H. [Mitsubishi Corp., Tokyo (Japan); Araki, M.; Nakazawa, T.

    1997-11-30

    This paper reports features of a wafer washing technology, a new IC wafer washing process, its pure water saving effect, and a `QC washing` which has pure water saving effect in the wafer washing. Wafer washing processes generally include the SC1 process (using ammonia + hydrogen peroxide aqueous solution) purposed for removing contamination due to ultrafine particles, the SC2 process (using hydrochloric acid + hydrogen peroxide aqueous solution) purposed for removing contamination due to heavy metals, the piranha washing process (using hot sulfuric acid + hydrogen peroxide aqueous solution) purposed for removing contamination due to organic matters, and the DHF (using dilute hydrofluoric acid) purposed for removing natural oxide films. Natural oxide films are now remained as surface protection films, by which surface contamination has been reduced remarkably. A high-temperature washing chemical circulating and filtering technology developed in Japan has brought about a reform in wafer washing processes having been used previously. Spin washing is used as a water saving measure, in which washing chemicals or pure water are sprayed onto one each of wafers which is spin-rotated, allowing washing and rinsing to be made with small amount of washing chemicals and pure water. The QC washing is a method to replace tank interior with pure was as quick as possible in order to increase the rinsing effect. 7 refs., 5 figs.

  1. Growing Galaxies Gently

    Science.gov (United States)

    2010-10-01

    New observations from ESO's Very Large Telescope have, for the first time, provided direct evidence that young galaxies can grow by sucking in the cool gas around them and using it as fuel for the formation of many new stars. In the first few billion years after the Big Bang the mass of a typical galaxy increased dramatically and understanding why this happened is one of the hottest problems in modern astrophysics. The results appear in the 14 October issue of the journal Nature. The first galaxies formed well before the Universe was one billion years old and were much smaller than the giant systems - including the Milky Way - that we see today. So somehow the average galaxy size has increased as the Universe has evolved. Galaxies often collide and then merge to form larger systems and this process is certainly an important growth mechanism. However, an additional, gentler way has been proposed. A European team of astronomers has used ESO's Very Large Telescope to test this very different idea - that young galaxies can also grow by sucking in cool streams of the hydrogen and helium gas that filled the early Universe and forming new stars from this primitive material. Just as a commercial company can expand either by merging with other companies, or by hiring more staff, young galaxies could perhaps also grow in two different ways - by merging with other galaxies or by accreting material. The team leader, Giovanni Cresci (Osservatorio Astrofisico di Arcetri) says: "The new results from the VLT are the first direct evidence that the accretion of pristine gas really happened and was enough to fuel vigorous star formation and the growth of massive galaxies in the young Universe." The discovery will have a major impact on our understanding of the evolution of the Universe from the Big Bang to the present day. Theories of galaxy formation and evolution may have to be re-written. The group began by selecting three very distant galaxies to see if they could find evidence

  2. Cosmology and galaxy formation

    International Nuclear Information System (INIS)

    Jones, B.J.T.; Gonzalez, E.M.

    1985-05-01

    The aim of the present series of lectures is to be unashamedly pedagogical and present, in simple terms, an overview of our current thinking about our universe and the way in which we believe galaxies have formed. (orig./WL)

  3. Massive stars in galaxies

    International Nuclear Information System (INIS)

    Humphreys, R.M.

    1987-01-01

    The relationship between the morphologic type of a galaxy and the evolution of its massive stars is explored, reviewing observational results for nearby galaxies. The data are presented in diagrams, and it is found that the massive-star populations of most Sc spiral galaxies and irregular galaxies are similar, while those of Sb spirals such as M 31 and M 81 may be affected by morphology (via differences in the initial mass function or star-formation rate). Consideration is also given to the stability-related upper luminosity limit in the H-R diagram of hypergiant stars (attributed to radiation pressure in hot stars and turbulence in cool stars) and the goals of future observation campaigns. 88 references

  4. Interpretation of galaxy counts

    International Nuclear Information System (INIS)

    Tinsely, B.M.

    1980-01-01

    New models are presented for the interpretation of recent counts of galaxies to 24th magnitude, and predictions are shown to 28th magnitude for future comparison with data from the Space Telescope. The results supersede earlier, more schematic models by the author. Tyson and Jarvis found in their counts a ''local'' density enhancement at 17th magnitude, on comparison with the earlier models; the excess is no longer significant when a more realistic mixture of galaxy colors is used. Bruzual and Kron's conclusion that Kron's counts show evidence for evolution at faint magnitudes is confirmed, and it is predicted that some 23d magnitude galaxies have redshifts greater than unity. These may include spheroidal systems, elliptical galaxies, and the bulges of early-type spirals and S0's, seen during their primeval rapid star formation

  5. HERSCHEL SPECTROSCOPIC OBSERVATIONS OF LITTLE THINGS DWARF GALAXIES

    International Nuclear Information System (INIS)

    Cigan, Phil; Young, Lisa; Cormier, Diane; Lebouteiller, Vianney; Madden, Suzanne; Hunter, Deidre; Brinks, Elias; Elmegreen, Bruce; Schruba, Andreas; Heesen, Volker

    2016-01-01

    We present far-infrared (FIR) spectral line observations of five galaxies from the Little Things sample: DDO 69, DDO 70, DDO 75, DDO 155, and WLM. While most studies of dwarfs focus on bright systems or starbursts due to observational constraints, our data extend the observed parameter space into the regime of low surface brightness dwarf galaxies with low metallicities and moderate star formation rates. Our targets were observed with Herschel at the [C ii] 158 μm, [O i] 63 μm, [O iii] 88 μm, and [N ii] 122 μm emission lines using the PACS Spectrometer. These high-resolution maps allow us for the first time to study the FIR properties of these systems on the scales of larger star-forming complexes. The spatial resolution in our maps, in combination with star formation tracers, allows us to identify separate photodissociation regions (PDRs) in some of the regions we observed. Our systems have widespread [C ii] emission that is bright relative to continuum, averaging near 0.5% of the total infrared (TIR) budget—higher than in solar-metallicity galaxies of other types. [N ii] is weak, suggesting that the [C ii] emission in our galaxies comes mostly from PDRs instead of the diffuse ionized interstellar medium (ISM). These systems exhibit efficient cooling at low dust temperatures, as shown by ([O i]+[C ii])/TIR in relation to 60 μm/100 μm, and low [O i]/[C ii] ratios which indicate that [C ii] is the dominant coolant of the ISM. We observe [O iii]/[C ii] ratios in our galaxies that are lower than those published for other dwarfs, but similar to levels noted in spirals

  6. HERSCHEL SPECTROSCOPIC OBSERVATIONS OF LITTLE THINGS DWARF GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Cigan, Phil; Young, Lisa [Physics Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Cormier, Diane [Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Lebouteiller, Vianney; Madden, Suzanne [Laboratoire AIM, CEA/DSM—CNRS—Université Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Hunter, Deidre [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Brinks, Elias [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom); Elmegreen, Bruce [IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Hts., NY 10598 (United States); Schruba, Andreas [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Heesen, Volker, E-mail: pcigan@alumni.nmt.edu [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Collaboration: LITTLE THINGS Team

    2016-01-15

    We present far-infrared (FIR) spectral line observations of five galaxies from the Little Things sample: DDO 69, DDO 70, DDO 75, DDO 155, and WLM. While most studies of dwarfs focus on bright systems or starbursts due to observational constraints, our data extend the observed parameter space into the regime of low surface brightness dwarf galaxies with low metallicities and moderate star formation rates. Our targets were observed with Herschel at the [C ii] 158 μm, [O i] 63 μm, [O iii] 88 μm, and [N ii] 122 μm emission lines using the PACS Spectrometer. These high-resolution maps allow us for the first time to study the FIR properties of these systems on the scales of larger star-forming complexes. The spatial resolution in our maps, in combination with star formation tracers, allows us to identify separate photodissociation regions (PDRs) in some of the regions we observed. Our systems have widespread [C ii] emission that is bright relative to continuum, averaging near 0.5% of the total infrared (TIR) budget—higher than in solar-metallicity galaxies of other types. [N ii] is weak, suggesting that the [C ii] emission in our galaxies comes mostly from PDRs instead of the diffuse ionized interstellar medium (ISM). These systems exhibit efficient cooling at low dust temperatures, as shown by ([O i]+[C ii])/TIR in relation to 60 μm/100 μm, and low [O i]/[C ii] ratios which indicate that [C ii] is the dominant coolant of the ISM. We observe [O iii]/[C ii] ratios in our galaxies that are lower than those published for other dwarfs, but similar to levels noted in spirals.

  7. A Radio Study of the Ultra-luminous FIR Galaxy NGC 6240

    Science.gov (United States)

    Colbert, E.; Wilson, A. S.; Bland-Hawthorn, J.

    1993-05-01

    A number of galaxies observed in the IRAS mission are noted to emit ~ 99% of their bolometric flux in the FIR, with FIR luminosities in excess of 10(11) Lsun. The interacting galaxy NGC 6240 has often been referred to as the ``proto-typical'' ultra-luminous (L_FIR >~ 10(12) Lsun) FIR galaxy. The origin of the FIR excess remains a disputed subject in the literature. New observations of NGC 6240 were taken with the VLA at 20cm in the B-configuration, and at 3.6cm in the A-configuration. No significant radio emission was detected from or near the possible ultra-massive ``dark core'' hypothesized by Bland-Hawthorn et. al. (1991); however, approximately 30% of Seyfert galaxies have 20 cm radio luminosities weaker than the upper limit derived from the radio maps. The non-thermal radio emission from luminous FIR galaxies is tightly correlated with the FIR emission. Previous radio observations of NGC 6240 revealed two compact, steep-spectrum nuclear sources, nearly coincident with the two nuclear sources seen in optical images. The 2 images from the new VLA observations and 5 images from previous VLA observations are used to identify the morphological and spectral features of the strong, compact components in the nuclear regions (~ 3 kpc) from the nucleus. Feasible explanations for the radio emission are discussed. The models that have been proposed in the literature for the FIR excess of NGC 6240 are evaluated for consistency with the observed radio emission.

  8. Automated galaxy surface photometry

    International Nuclear Information System (INIS)

    Cawson, M.G.M.; Kibblewhite, E.J.; Disney, M.J.; Phillipps, S.

    1987-01-01

    Two-dimensional surface photometry of a very large number of galaxies on a deep Schmidt plate has been obtained using the Automatic Plate Measuring System (APM). A method of photometric calibration, suitable for APM measurements, via pixel-by-pixel comparison with CCD frames of a number of the brighter galaxies is described and its advantages are discussed. The same method is used to demonstrate the consistency of measurement of the APM machine when used for surface photometry. (author)

  9. Evolution of galaxies

    International Nuclear Information System (INIS)

    Palous, J.

    1987-01-01

    The proceedings contain 87 papers divided into 8 chapters. The chapter Bipolar outflows and star formations contains papers on optical and infrared observations of young bipolar outflow objects and the theory thereof, and on observations of cometary nebulae. The chapter Masers and early stellar evolution discusses molecular masers and star forming regions. The following chapter contains papers on initial mass function and star formation rates in galaxies. The chapter Clusters and star formation contains data on OB associations and open star clusters, their development and observations, CO and H 2 in our galaxy, the four vector model of radio emission and an atlas of the wavelength dependence of ultraviolet extinction in the Galaxy. The most voluminous is the chapter Evolution of galaxies. It contains papers on the theories of the physical and chemodynamic development of galaxies of different types, rotation research and rotation velocities of galaxies and their arms, and on mathematical and laboratory models of morphological development. Chapter seven contains papers dealing with active extragalactic objects, quasars and active galactic nuclei. The last chapter discusses cosmological models, the theory of the inflationary universe, and presents an interpretation of the central void and X-ray background. (M.D.). 299 figs., 48 tabs., 1651 refs

  10. Coma cluster of galaxies

    Science.gov (United States)

    1999-01-01

    Atlas Image mosaic, covering 34' x 34' on the sky, of the Coma cluster, aka Abell 1656. This is a particularly rich cluster of individual galaxies (over 1000 members), most prominently the two giant ellipticals, NGC 4874 (right) and NGC 4889 (left). The remaining members are mostly smaller ellipticals, but spiral galaxies are also evident in the 2MASS image. The cluster is seen toward the constellation Coma Berenices, but is actually at a distance of about 100 Mpc (330 million light years, or a redshift of 0.023) from us. At this distance, the cluster is in what is known as the 'Hubble flow,' or the overall expansion of the Universe. As such, astronomers can measure the Hubble Constant, or the universal expansion rate, based on the distance to this cluster. Large, rich clusters, such as Coma, allow astronomers to measure the 'missing mass,' i.e., the matter in the cluster that we cannot see, since it gravitationally influences the motions of the member galaxies within the cluster. The near-infrared maps the overall luminous mass content of the member galaxies, since the light at these wavelengths is dominated by the more numerous older stellar populations. Galaxies, as seen by 2MASS, look fairly smooth and homogeneous, as can be seen from the Hubble 'tuning fork' diagram of near-infrared galaxy morphology. Image mosaic by S. Van Dyk (IPAC).

  11. PEARS Emission Line Galaxies

    Science.gov (United States)

    Pirzkal, Nor; Rothberg, Barry; Ly, Chun; Rhoads, James E.; Malhotra, Sangeeta; Grogin, Norman A.; Dahlen, Tomas; Meurer, Gerhardt R.; Walsh, Jeremy; Hathi, Nimish P.; hide

    2012-01-01

    We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitless grism spectroscopic data obtained vl'ith the Advanced Camera for Surveys on HST. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random surveY of galaxies, as well as the availability of a wide variety of ancillary observations to support the spectroscopic results. Using the PEARS data we are able to identify star forming galaxies within the redshift volume 0 galaxies down to a limiting flux of approx 10 - 18 erg/s/sq cm . The ELRs have also been compared to the properties of the host galaxy, including morphology, luminosity, and mass. From this analysis we find three key results: 1) The computed line luminosities show evidence of a flattening in the luminosity function with increasing redshift; 2) The star forming systems show evidence of disturbed morphologies, with star formation occurring predominantly within one effective (half-light) radius. However, the morphologies show no correlation with host stellar mass; and 3) The number density of star forming galaxies with M(*) >= 10(exp 9) Solar M decreases by an order of magnitude at z<=0.5 relative to the number at 0.5 < z < 0.9 in support of the argument for galaxy downsizing.

  12. The Milky Way galaxy

    International Nuclear Information System (INIS)

    Woerden, H. van; Allen, R.J.; Burton, W.B.

    1985-01-01

    IAU Symposium 106, held at the Kapteyn Institute in Groningen, presents an overview of all major aspects of galactic astronomy. The vast subject is covered in 20 authoritative review papers and 22 invited papers, each with discussion, plus 81 shorter contributions. The book opens with 4 reviews by historians of science, outlining the history of galactic research. Part 2 deals with (i) galactic rotation, (ii) the large-scale distributions of matter, of both old and young stellar populations, and of the atomic, molecular and high-energy components of the interstellar medium, (iii) small-scale structure in the gas, (iv) the galactic nucleus, (v) the high-velocity clouds. Part 3 discusses the dynamics of the local group of Galaxies and of the Milky Way-Magellanic clouds system, the dynamical and chemical evolution of the Galaxy and of its disk and halo components and the formation of the Galaxy. The controversial subject of spiral structure and star formation is analyzed in several extensive reviews and lively discussions, featuring both observational and theoretical developments. Results of extragalactic research are blended with studies of our Galaxy throughout the book, and there is a separate comparison between Andromeda and Milky Way Galaxies. The Symposium featured the first maps produced by IRAS, and results from most major telescopes in a variety of wavebands. Many review papers present material not published elsewhere. The book closes with a lecture on life in the Galaxy and with an imaginative symposium summary. (orig.)

  13. RELATIVISTIC PLASMA AS THE DOMINANT SOURCE OF THE OPTICAL CONTINUUM EMISSION IN THE BROAD-LINE RADIO GALAXY 3C 120

    International Nuclear Information System (INIS)

    Leon-Tavares, J.; Lobanov, A. P.; Arshakian, T. G.; Chavushyan, V. H.; Doroshenko, V. T.; Sergeev, S. G.; Efimov, Y. S.; Nazarov, S. V.

    2010-01-01

    We report a relation between radio emission in the inner jet of the Seyfert galaxy 3C 120 and optical continuum emission in this galaxy. Combining the optical variability data with multi-epoch high-resolution very long baseline interferometry observations reveals that an optical flare rises when a superluminal component emerges into the jet, and its maxima is related to the passage of such component through the location of a stationary feature at a distance of ∼1.3 pc from the jet origin. This indicates that a significant fraction of the optical continuum produced in 3C 120 is non-thermal, and it can ionize material in a sub-relativistic wind or outflow. We discuss implications of this finding for the ionization and structure of the broad emission line region, as well as for the use of broad emission lines for determining black hole masses in radio-loud active galactic nucleus.

  14. IUE and Einstein observations of the LINER galaxy NGC 4579

    Science.gov (United States)

    Reichert, G. A.; Puchnarewicz, E. M.; Mason, K. O.

    1990-01-01

    Results of International Ultraviolet Explorer (IUE) and Einstein observations of the LINER galaxy NGC 4579 are reported. Spatial profiles of the long wavelength IUE emission show a two component structure, with an unresolved core superimposed on broader underlying emission. The core spectrum shows strong C II lambda 2326 and broad Mg II lambda 2800 emission, and perhaps emission due to blends of Fe II multiplets (2300 to 23600 angstrom). The short wavelength emission is spatially unresolved, and shows C II lambda 1335, C III lambda 1909 broad C IV lambda 1550 emission, and a broad feature at approximately 1360 angstrom which may be due to 0.1 lambda 1356. Contrary to previous reports no evidence for He II lambda 1640 is found in the spectrum. An unresolved x ray source is detected at the location of the nucleus; its spectrum is well fitted by a power law of energy slope alpha approximately -0.5. These results further support the idea that NGC 4579 may contain a dwarf Seyfert nucleus.

  15. Matching Supernovae to Galaxies

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    One of the major challenges for modern supernova surveys is identifying the galaxy that hosted each explosion. Is there an accurate and efficient way to do this that avoids investing significant human resources?Why Identify Hosts?One problem in host galaxy identification. Here, the supernova lies between two galaxies but though the centroid of the galaxy on the right is closer in angular separation, this may be a distant background galaxy that is not actually near the supernova. [Gupta et al. 2016]Supernovae are a critical tool for making cosmological predictions that help us to understand our universe. But supernova cosmology relies on accurately identifying the properties of the supernovae including their redshifts. Since spectroscopic followup of supernova detections often isnt possible, we rely on observations of the supernova host galaxies to obtain redshifts.But how do we identify which galaxy hosted a supernova? This seems like a simple problem, but there are many complicating factors a seemingly nearby galaxy could be a distant background galaxy, for instance, or a supernovas host could be too faint to spot.The authors algorithm takes into account confusion, a measure of how likely the supernova is to be mismatched. In these illustrations of low (left) and high (right) confusion, the supernova is represented by a blue star, and the green circles represent possible host galaxies. [Gupta et al. 2016]Turning to AutomationBefore the era of large supernovae surveys, searching for host galaxies was done primarily by visual inspection. But current projects like the Dark Energy Surveys Supernova Program is finding supernovae by the thousands, and the upcoming Large Synoptic Survey Telescope will likely discover hundreds of thousands. Visual inspection will not be possible in the face of this volume of data so an accurate and efficient automated method is clearly needed!To this end, a team of scientists led by Ravi Gupta (Argonne National Laboratory) has recently

  16. INTERACTIONS OF GALAXIES IN THE GALAXY CLUSTER ENVIRONMENT

    International Nuclear Information System (INIS)

    Park, Changbom; Hwang, Ho Seong

    2009-01-01

    We study the dependence of galaxy properties on the clustercentric radius and the environment attributed to the nearest neighbor galaxy using the Sloan Digital Sky Survey galaxies associated with the Abell galaxy clusters. We find that there exists a characteristic scale where the properties of galaxies suddenly start to depend on the clustercentric radius at fixed neighbor environment. The characteristic scale is 1-3 times the cluster virial radius depending on galaxy luminosity. Existence of the characteristic scale means that the local galaxy number density is not directly responsible for the morphology-density relation in clusters because the local density varies smoothly with the clustercentric radius and has no discontinuity in general. What is really working in clusters is the morphology-clustercentric radius-neighbor environment relation, where the neighbor environment means both neighbor morphology and the local mass density attributed to the neighbor. The morphology-density relation appears working only because of the statistical correlation between the nearest neighbor distance and the local galaxy number density. We find strong evidence that the hydrodynamic interactions with nearby early-type galaxies is the main drive to quenching star formation activity of late-type galaxies in clusters. The hot cluster gas seems to play at most a minor role down to one tenth of the cluster virial radius. We also find that the viable mechanisms which can account for the clustercentric radius dependence of the structural and internal kinematics parameters are harassment and interaction of galaxies with the cluster potential. The morphology transformation of the late-type galaxies in clusters seems to have taken place through both galaxy-galaxy hydrodynamic interactions and galaxy-cluster/galaxy-galaxy gravitational interactions.

  17. INTERACTIONS OF GALAXIES IN THE GALAXY CLUSTER ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    Park, Changbom; Hwang, Ho Seong [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of)], E-mail: cbp@kias.re.kr, E-mail: hshwang@kias.re.kr

    2009-07-10

    We study the dependence of galaxy properties on the clustercentric radius and the environment attributed to the nearest neighbor galaxy using the Sloan Digital Sky Survey galaxies associated with the Abell galaxy clusters. We find that there exists a characteristic scale where the properties of galaxies suddenly start to depend on the clustercentric radius at fixed neighbor environment. The characteristic scale is 1-3 times the cluster virial radius depending on galaxy luminosity. Existence of the characteristic scale means that the local galaxy number density is not directly responsible for the morphology-density relation in clusters because the local density varies smoothly with the clustercentric radius and has no discontinuity in general. What is really working in clusters is the morphology-clustercentric radius-neighbor environment relation, where the neighbor environment means both neighbor morphology and the local mass density attributed to the neighbor. The morphology-density relation appears working only because of the statistical correlation between the nearest neighbor distance and the local galaxy number density. We find strong evidence that the hydrodynamic interactions with nearby early-type galaxies is the main drive to quenching star formation activity of late-type galaxies in clusters. The hot cluster gas seems to play at most a minor role down to one tenth of the cluster virial radius. We also find that the viable mechanisms which can account for the clustercentric radius dependence of the structural and internal kinematics parameters are harassment and interaction of galaxies with the cluster potential. The morphology transformation of the late-type galaxies in clusters seems to have taken place through both galaxy-galaxy hydrodynamic interactions and galaxy-cluster/galaxy-galaxy gravitational interactions.

  18. The Galaxy Evolution Probe

    Science.gov (United States)

    Glenn, Jason; Galaxy Evolution Probe Team

    2018-01-01

    The Galaxy Evolution Probe (GEP) is a concept for a far-infrared observatory to survey large regions of sky for star-forming galaxies from z = 0 to beyond z = 3. Our knowledge of galaxy formation is incomplete and requires uniform surveys over a large range of redshifts and environments to accurately describe mass assembly, star formation, supermassive black hole growth, interactions between these processes, and what led to their decline from z ~ 2 to the present day. Infrared observations are sensitive to dusty, star-forming galaxies, which have bright polycyclic aromatic hydrocarbon (PAH) emission features and warm dust continuum in the rest-frame mid infrared and cooler thermal dust emission in the far infrared. Unlike previous far-infrared continuum surveys, the GEP will measure photometric redshifts commensurate with galaxy detections from PAH emission and Si absorption features, without the need for obtaining spectroscopic redshifts of faint counterparts at other wavelengths.The GEP design includes a 2 m diameter telescope actively cooled to 4 K and two instruments: (1) An imager covering 10 to 300 um with 25 spectral resolution R ~ 8 bands (with lower R at the longest wavelengths) to detect star-forming galaxies and measure their redshifts photometrically. (2) A 23 – 190 um, R ~ 250 dispersive spectrometer for redshift confirmation and identification of obscured AGN using atomic fine-structure lines. Lines including [Ne V], [O IV], [O III], [O I], and [C II] will probe gas physical conditions, radiation field hardness, and metallicity. Notionally, the GEP will have a two-year mission: galaxy surveys with photometric redshifts in the first year and a second year devoted to follow-up spectroscopy. A comprehensive picture of star formation in galaxies