Physics Commons^™

The Close Agn Reference Survey (Cars): A Parsec-Scale Multi-Phase Outflow In The Super-Eddington Nls1 Mrk 1044, N. Winkel, B. Husemann, M. Singha, V. N. Bennert, F. Combes, T. A. Davis, M. Gaspari, K. Jahnke, R. Mcelroy, C. P. O'Dea, M. A. Pérez-Torres

Physics

Context. The interaction between active galactic nuclei (AGNs) and their host galaxies is scarcely resolved. Narrow-line Seyfert 1 (NLS1) galaxies are believed to represent AGN at early stages of their evolution and to allow one to observe feeding and feedback processes at high black hole accretion rates.

Aims. We aim to constrain the properties of the ionised gas outflow in Mrk 1044, a nearby super-Eddington accreting NLS1. Based on the outflow energetics and the associated timescales, we estimate the outflow’s future impact on the ongoing host galaxy star formation on different spatial scales.

Methods. We applied a spectroastrometric analysis to …

The Close Agn Reference Survey (Cars): Tracing The Circumnuclear Star Formation In The Super-Eddington Nls1 Mrk 1044, N. Winkel, T. A. Davis, I. Smirnova-Pinchukova, V. N. Bennert, F. Combes, M. Gaspari, K. Jahnke, J. Neumann, C. P. O'Dea, M. Pérez-Torres, M. Singha, G. R. Tremblay, H. W. Rix

Physics

Context. The host galaxy conditions for rapid supermassive black hole growth are poorly understood. Narrow-line Seyfert 1 (NLS1) galaxies often exhibit high accretion rates and are hypothesized to be prototypes of active galactic nuclei (AGN) at an early stage of their evolution.

Aims. We present adaptive optics (AO) assisted VLT MUSE NFM observations of Mrk 1044, the nearest super-Eddington accreting NLS1. Together with archival MUSE WFM data, we aim to understand the host galaxy processes that drive Mrk 1044’s black hole accretion.

Methods. We extracted the faint stellar continuum emission from the AGN-deblended host and performed spatially resolved emission line …

Spatially Offset Active Galactic Nuclei. Ii. Triggering In Galaxy Mergers, R Scott Barrows, Julia M. Comerford, Jenny E. Greene, David Pooley

Physics and Astronomy Faculty Research

Galaxy mergers are likely to play a role in triggering active galactic nuclei (AGNs), but the conditions under which this process occurs are poorly understood. In Paper I, we constructed a sample of spatially offset X-ray AGNs that represent galaxy mergers hosting a single AGN. In this paper, we use our offset AGN sample to constrain the parameters that affect AGN observability in galaxy mergers. We also construct dual-AGN samples with similar selection properties for comparison. We find that the offset AGN fraction shows no evidence for a dependence on AGN luminosity, while the dual-AGN fractions show stronger evidence for …

A Deep Look At The Nuclear Region Of Ugc 5101 Through High Angular Resolution Mid-Ir Data With Gtc/Canaricam, M. Martínez-Paredes, Almudena Alonso-Herrero, Itziar Aretxaga, C. Ramos Almeida, A. Hernán-Caballero, O. González-Martín, M. Pereira-Santaella, Christopher Packham, A. Asensio Ramos, T. Díaz-Santos, Moshe Elitzur, P. Esquej, I. García-Bernete, Masatoshi Imanishi, Nancy A. Levenson, José Miguel Rodríguez Espinosa

Physics and Astronomy Faculty Publications

We present an analysis of the nuclear infrared (IR, 1.6–18 μm) emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of its active galactic nucleus (AGN) and its obscuring material. We use new mid-IR high angular resolution (0.3–0.5 arcsec) imaging using the Si-2 filter (λ_C = 8.7 μm) and 7.5–13 μm spectroscopy taken with CanariCam (CC) on the 10.4 m Gran Telescopio CANARIAS. We also use archival Hubble Space Telescope/NICMOS and Subaru/COMICS imaging and Spitzer/IRS spectroscopy. We estimate the near- and mid-IR unresolved nuclear emission by modelling the imaging data with GALFIT. We decompose …

Strong Variability Of The Coronal Line Region In Ngc 5548, Hermine Landt, Martin J. Ward, Katrien C. Steenbrugge, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present the second extensive study of the coronal line variability in an active galaxy. Our data set for the well-studied Seyfert galaxy NGC 5548 consists of five epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about five years and three epochs of X-ray spectroscopy overlapping in time with it. Whereas the broad emission lines and hot dust emission varied only moderately, the coronal lines varied strongly. However, the observed high variability is mainly due to a flux decrease. Using the optical [Fe vii] and X-ray O vii emission lines we estimate that the coronal line gas …

Variability Of The Coronal Line Region In Ngc 4151, Hermine Landt, Martin J. Ward, Katrien C. Steenbrugge, Gary J. Ferland

Physics and Astronomy Faculty Publications

We present the first extensive study of the coronal line variability in an active galaxy. Our data set for the nearby source NGC 4151 consists of six epochs of quasi-simultaneous optical and near-infrared spectroscopy spanning a period of about 8 yr and five epochs of X-ray spectroscopy overlapping in time with it. None of the coronal lines showed the variability behaviour observed for the broad emission lines and hot dust emission. In general, the coronal lines varied only weakly, if at all. Using the optical [Fe vii] and X-ray O vii emission lines we estimate that the coronal line gas …

Spitzer Space Telescope Measurements Of Dust Reverberation Lags In The Seyfert 1 Galaxy Ngc 6418, Billy Vazquez, Pasquale Galianni, Michael Richmond, Andrew Robinson, David J. Axon, Keith Horne, Triana Almeyda, Michael Fausnaugh, Bradley M. Peterson, Mark Bottorff, Jack Gallimore, Moshe Elitzur, Hagai Netzer, Thaisa Storchi-Bergmann, Alessandro Marconi, Alessandro Capetti, Dan Batcheldor, Catherine Buchanan, Giovanna Stirpe, Makoto Kishimoto, Christopher Packham, Enrique Perez, Clive Tadhunter, John Upton, Vincente Estrada-Carpenter

Physics and Astronomy Faculty Publications

We present results from a 15 month campaign of high-cadence (~3 days) mid-infrared Spitzer and optical (B and V) monitoring of the Seyfert 1 galaxy NGC 6418, with the objective of determining the characteristic size of the dusty torus in this active galactic nucleus (AGN). . . .

For the remainder of the abstract, please visit:

http://dx.doi.org/10.1088/0004-637X/801/2/127

The Dust Geometric Distribution In Seyfert 1 And Seyfert 2 Galaxies, Isolated And In Interaction, S. Mendoza-Castrejón, D. Dultzin, Y. Krongold, J. J. González, Moshe Elitzur

Physics and Astronomy Faculty Publications

We analyse the mid-infrared (MIR) spectra of 39 Seyfert galaxies observed with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. Our sample consists of 19 Seyfert type 1 (Sy1) galaxies, three intermediate Seyfert galaxies and 17 type 2 Seyfert (Sy2) galaxies in the nearby Universe. This sample was extracted from a larger sample, the circumgalactic environment of which was studied in a previous work by Dultzin-Hacyan et al., who found that Sy2 objects are in interaction more frequently than normal galaxies, while Sy1s are not. In this article, we study the silicate dust distribution that dominates the …

Galaxy Zoo: Are Bars Responsible For The Feeding Of Active Galactic Nuclei At 0.2 < Z < 1.0?, Edmond Cheung, Jonathan R. Trump, E. Athanassoula, Steven P. Bamford, Eric F. Bell, A. Bosma, Carolin N. Cardamone, Kevin R. V. Casteels, S. M. Faber, Jerome J. Fang, Lucy F. Fortson, Dale D. Kocevski, David C. Koo, Seppo Laine, Chris Lintott, Karen L. Masters, Thomas Melvin, Robert C. Nichol, Kevin Schawinski, Brooke Simmons, Rebecca Smethurst, Kyle W. Willett

Physics and Astronomy Faculty Publications

We present a new study investigating whether active galactic nuclei (AGN) beyond the local universe are preferentially fed via large-scale bars. Our investigation combines data from Chandra and Galaxy Zoo: Hubble (GZH) in the AEGIS (All-wavelength Extended Groth strip International Survey), COSMOS (Cosmological Evolution Survey), and (Great Observatories Origins Deep Survey-South) GOODS-S surveys to create samples of face-on, disc galaxies at 0.2 < z < 1.0. We use a novel method to robustly compare a sample of 120 AGN host galaxies, defined to have 10⁴² erg s⁻¹ < L_X < 10⁴⁴ erg s⁻¹, with inactive control galaxies matched in stellar mass, rest-frame colour, size, Sérsic index, and redshift. Using the GZH bar classifications of each sample, we demonstrate that …

No More Active Galactic Nuclei In Clumpy Disks Than In Smooth Galaxies At Z ~ 2 In Candels/3d-Hst*, Jonathan R. Trump, Guillermo Barro, Stéphanie Juneau, Benjamin J. Weiner, Bin Luo, Gabriel B. Brammer, Eric F. Bell, W. N. Brandt, Avishai Dekel, Yicheng Guo, Philip F. Hopkins, David C. Koo, Dale D. Kocevski, Daniel H. Mcintosh, Ivelina Momcheva, S. M. Faber, Henry C. Ferguson, Norman A. Grogin, Jeyhan Kartaltepe, Anton M. Koekemoer, Jennifer Lotz, Michael Maseda, Mark Mozena, Kirpal Nandra, David J. Rosario, Gergory R. Zeimann

Physics and Astronomy Faculty Publications

We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to investigate if active galactic nuclei (AGNs) are preferentially fueled by violent disk instabilities funneling gas into galaxy centers at 1.3 < z < 2.4. We select galaxies undergoing gravitational instabilities using the number of clumps and degree of patchiness as proxies. The CANDELS visual classification system is used to identify 44 clumpy disk galaxies, along with mass-matched comparison samples of smooth and intermediate morphology galaxies. We note that despite being mass-matched and having similar star formation rates, the smoother galaxies tend to be smaller disks with more prominent bulges compared to the clumpy galaxies. The lack of smooth extended disks is probably a general feature of the z ~ 2 galaxy population, and means we cannot directly compare with the clumpy and smooth extended disks observed at lower redshift. We find that z ~ 2 clumpy galaxies have slightly enhanced AGN fractions selected by integrated line ratios (in the mass-excitation method), but the spatially resolved line ratios indicate this is likely due to extended phenomena rather than nuclear AGNs. Meanwhile, the X-ray data show that …

The Properties Of Post-Starburst Quasars Based On Optical Spectroscopy, Sabrina L. Cales, Michael S. Brotherton, Zhaohui Shang, Jessie C. Runnoe, Michael A. Dipompeo, Vardha Nicola Bennert, Gabriela Canalizo, Kyle D. Hiner, R. Stoll, Rajib Ganguly, Aleksandar Diamond-Stanic

Physics

We present optical spectroscopy of a sample of 38 post-starburst quasars (PSQs) at z ~ 0.3, 29 of which have morphological classifications based on Hubble Space Telescope imaging. These broad-lined active galactic nuclei (AGNs) possess the spectral signatures of massive intermediate-aged stellar populations, making them potentially useful for studying connections between nuclear activity and host galaxy evolution. We model the spectra in order to determine the ages and masses of the host stellar populations, and the black hole masses and Eddington fractions of the AGNs. Our model components include an instantaneous starburst, a power law, and emission lines. We find …

Accretion Properties Of High- And Low-Excitation Young Radio Galaxies, Donghoon Son, Jong-Hak Woo, Sang Chul Kim, Hai Fu, Nozomu Kawakatu, Vardha N. Bennert, Tohru Nagao, Daeseong Park

Physics

Young radio galaxies (YRGs) provide an ideal laboratory to explore the connection between the accretion disk and radio jet thanks to their recent jet formation. We investigate the relationship between the emission-line properties, the black hole accretion rate, and the radio properties using a sample of 34 low-redshift (z < 0.4) YRGs. We classify YRGs as high-excitation galaxies (HEGs) and low-excitation galaxies (LEGs) based on the flux ratio of high-ionization to low-ionization emission lines. Using the Hα luminosities as a proxy of accretion rate, we find that HEGs in YRGs have ~1 dex higher Eddington ratios than LEGs in YRGs, suggesting that HEGs have a higher mass accretion rate or higher radiative efficiency than LEGs. In agreement with previous studies, we find that the luminosities of emission lines, in particular Hα, are correlated with radio core luminosity, suggesting that accretion and young radio activities are fundamentally connected.

The Lick Agn Monitoring Project 2011: Recalibrating Single-Epoch Virial Black Hole Mass Estimates, Daeseong Park, Jong-Hak Woo, Tommaso Treu, Aaron J. Barth, Misty C. Bentz, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor Gates, Jenny E. Greene, Matthew A. Malkan, Jonelle Walsh

Physics

We investigate the calibration and uncertainties of black hole (BH) mass estimates based on the single-epoch (SE) method, using homogeneous and high-quality multi-epoch spectra obtained by the Lick Active Galactic Nucleus (AGN) Monitoring Project for nine local Seyfert 1 galaxies with BH masses <10⁸ M _☉. By decomposing the spectra into their AGNs and stellar components, we study the variability of the SE Hβ line width (full width at half-maximum intensity, FWHM_Hβ or dispersion, σ_Hβ) and of the AGN continuum luminosity at 5100 Å (L ₅₁₀₀). From the distribution of the "virial products" ( …

Megamaser Detection And Nuclear Obscuration In Seyfert Galaxies, M. Ramolla, M. Hass, V. N. Bennert, R. Chini

Physics

We revisit the relation between H₂O maser detection rate and nuclear obscuration for a sample of 114 Seyfert galaxies drawn from the CfA, 12 μm, and IRAS F25/F60 catalogs. These sources have mid-infrared spectra from the Spitzer Space Telescope and we search for accompanying X-ray and [O III] 5007 Å fluxes from the literature. We use the strength of the [O IV] 25.9 μm emission line as a tracer of the intrinsic AGN strength. After the normalization by [O IV], the observed X-ray flux provides information about X-ray absorption. The distribution of X-ray/[O IV] flux ratios …

The Lick Agn Monitoring Project: Alternate Routes To A Broad-Line Region Radius, Jenny E. Greene, Carol E. Hood, Aaron J. Barth, Vardha N. Bennert, Misty C. Benz, Alexei V. Filippenko, Elinor Gates, Matthew A. Malkan, Tommaso Treu, Jonelle L. Walsh, Jong-Hak Woo

Physics

It is now possible to estimate black hole (BH) masses across cosmic time, using broad emission lines in active galaxies. This technique informs our views of how galaxies and their central BHs coevolve. Unfortunately, there are many outstanding uncertainties associated with these "virial" mass estimates. One of these comes from using the accretion luminosity to infer a size for the broad-line region (BLR). Incorporating the new sample of low-luminosity active galaxies from our recent monitoring campaign at Lick Observatory, we recalibrate the radius-luminosity relation with tracers of the accretion luminosity other than the optical continuum. We find that the radius …

The Lick Agn Monitoring Project: Velocity-Delay Maps From The Maximum-Entropy Method For Arp 151, Misty C. Bentz, Keith Horne, Aaron J. Barth, Vardha Nicola Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor L. Gates, Matthew A. Malkan, Takeo Minezaki, Tommaso Treu, Jong-Hak Woo, Jonelle L. Walsh

Physics

We present velocity-delay maps for optical H I, He I, and He II recombination lines in Arp 151, recovered by fitting a reverberation model to spectrophotometric monitoring data using the maximum-entropy method. H I response is detected over the range 0-15 days, with the response confined within the virial envelope. The Balmer-line maps have similar morphologies but exhibit radial stratification, with progressively longer delays for Hγ to Hβ to Hα. The He I and He II response is confined within 1-2 days. There is a deficit of prompt response in the Balmer-line cores but strong prompt response in the red …

The Lick Agn Monitoring Project: Reverberation Mapping Of Optical Hydrogen And Helium Recombination Lines, Misty C. Bentz, Jonelle L. Walsh, Aaron J. Barth, Yuzuru Yoshii, Jong-Hak Woo, Xiaofeng Wang, Tommaso Treu, Carol E. Thornton, Rachel A. Street, Thea N. Steele, Jeffrey M. Silverman, Frank J.D. Serduke, Yu Sakata, Takeo Minezaki, Matthew A. Malkan, Weidong Li, Nicholas Lee, Kyle D. Hiner, Marton G. Hidas, Jenny E. Greene, Elinor L. Gates, Mohan Ganeshalingam, Alexei V. Filippenko, Gabriela Canalizo, Vardha N. Bennert, Nairn Baliber

Physics

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3 m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~10⁶-10⁷ M _☉ and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hβ emission, which we have previously reported. We present …

The Lick Agn Monitoring Project: The M Bh-Σ* Relation For Reverberation-Mapped Active Galaxies, Jong-Hak Woo, Tommaso Treu, Aaron J. Barth, Shelley A. Wright, Jonelle L. Walsh, Misty C. Bentz, Paul Martini, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor Gates, Jenny Greene, Weidong Li, Matthew A. Malkan, Daniel Stern, Takeo Minezaki

Physics

To investigate the black hole mass versus stellar velocity dispersion (M _BH-σ_*) relation of active galaxies, we measured the velocity dispersions of a sample of local Seyfert 1 galaxies, for which we have recently determined black hole masses using reverberation mapping. For most objects, stellar velocity dispersions were measured from high signal-to-noise ratio optical spectra centered on the Ca II triplet region (~8500 Å), obtained at the Keck, Palomar, and Lick Observatories. For two objects, in which the Ca II triplet region was contaminated by nuclear emission, the measurement was based on high-quality H-band spectra …

Discovery Of A Young L Dwarf Binary, Sdss224953.47+004404.6ab, Katelyn N. Allers, Michael C. Liu, Trent J. Dupuy, Michael C. Cushing

Faculty Journal Articles

No abstract provided.

The Lick Agn Monitoring Project: Broad-Line Region Radii And Black Hole Masses From Reverberation Mapping Of HSs, Misty C. Bentz, Jonelle L. Walsh, Aaron J. Barth, Nairn Baliber, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Mohan Ganeshalingam, Elinor L. Gates, Jenny E. Greene, Marton G. Hidas, Kyle D. Hiner, Nicholas Lee, Weidong Li, Matthew A. Malkan, Takeo Minezaki, Yu Sakata, Frank J.D. Serduke, Jeffrey M. Silverman, Thea N. Steele, Daniel Stern, Rachel A. Street, Carol E. Thornton, Tommaso Treu, Xiaofeng Wang, Jong-Hak Woo, Yuzuru Yoshii

Physics

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~10⁶-10⁷ M _☉ and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hβ emission. We present here the light curves for all …

The Lick Agn Monitoring Project: Photometric Light Curves And Optical Variability Characteristics, Jonelle L. Walsh, Takeo Minezaki, Misty C. Bentz, Aaron J. Barth, Nairn Baliber, Weidong Li, Daniel Stern, Vardha Nicola Bennert, Timothy M. Brown, Gabriela Canalizo, Alexei V. Filippenko, Elinor L. Gates, Jenny E. Greene, Matthew A. Malkan, Yu Sakata, Rachel A. Street, Tommaso Treu, Jong-Hak Woo, Yuzuru Yoshii

Physics

The Lick AGN Monitoring Project targeted 13 nearby Seyfert 1 galaxies with the intent of measuring the masses of their central black holes using reverberation mapping. The sample includes 12 galaxies selected to have black holes with masses roughly in the range 10⁶-10⁷ M _☉, as well as the well-studied active galactic nucleus (AGN) NGC 5548. In conjunction with a spectroscopic monitoring campaign, we obtained broadband B and V images on most nights from 2008 February through 2008 May. The imaging observations were carried out by four telescopes: the 0.76 m Katzman Automatic Imaging Telescope, the …

A Search For H2O Megamasers In High-Z Type-2 Active Galactic Nuclei, Vardha N. Bennert, Richard Barvainis, Christian Henkel, Robert Antonucci

Physics

We report a search for H₂O megamasers in 274 SDSS type-2 active galactic nuclei (AGNs; 0.3 <z< 0.83), half of which can be classified as type-2 quasi-stellar objects (QSOs) from their [O III] 5007 luminosity, using the Robert C. Byrd Green Bank Telescope (GBT) and the Effelsberg 100 m radio telescope. Apart from the detection of the extremely luminous water vapor megamaser SDSS J080430.99+360718.1, already reported by Barvainis & Antonucci, we do not find any additional line emission. This high rate of nondetections is compared to the water maser luminosity function created from the 78 water maser galaxies known to date and its extrapolation toward the higher luminosities of "gigamasers" that we would have been able to detect given the sensitivity of our survey. The properties of the known water masers are summarized and discussed with respect to the nature of high-z type-2 AGNs and megamasers in general. In the Appendix, we list 173 additional objects (mainly radio galaxies, but also QSOs and galaxies) that were observed with the GBT, the Effelsberg 100 m radio telescope, or Arecibo Observatory without leading to the detection of water maser emission.

First Results From The Lick Agn Monitoring Project: The Mass Of The Black Hole In Arp 151, Misty C. Bentz, Jonelle L. Walsh, Aaron J. Barth, Nairn Baliber, Nicola Bennert, Gabriela Canalizo, Alexei V. Filippenko, Mohan Ganeshalingam, Elinor L. Gates, Jenny E. Greene, Marton G. Hidas, Kyle D. Hiner, Nicholas Lee, Weidong Li, Matthew A. Malkan, Takeo Minezaki, Frank J.D. Serduke, Joshua H. Shiode, Jeffrey M. Silverman, Thea N. Steele, Daniel Stern, Rachel A. Street, Carol E. Thornton, Tommaso Treu, Xiaofeng Wang, Jong-Hak Woo, Yuzuru Yoshii

Physics

We have recently completed a 64 night spectroscopic monitoring campaign at the Lick Observatory 3 m Shane telescope with the aim of measuring the masses of the black holes in 13 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~10⁶-10⁷ M_☉. We present here the first results from this project—the mass of the central black hole in Arp 151. Strong variability throughout the campaign led to an exceptionally clean Hβ lag measurement in this object of 4.25_−0.66^+0.68 days in the observed frame. Coupled with the width of the Hβ emission line in the variable spectrum, we determine a black …

Size And Properties Of The Narrow-Line Region In Seyfert-1 Galaxies From Spatially-Resolved Optical Spectroscopy, N. Bennert, B. Jungwiert, S. Komossa, M. Hass, R. Chini

Physics

Context.Spatially resolved emission-line spectroscopy is a powerful tool for determining the physical conditions in the narrow-line region (NLR) of active galactic nuclei (AGNs). We recently used optical long-slit spectroscopy to study the NLRs of a sample of six Seyfert-2 galaxies. We have shown that such an approach, in comparison to the commonly used [ ] narrow-band imaging alone, allows us to probe the size of the NLR in terms of AGN photoionisation. Moreover, several physical parameters of the NLR can be directly accessed. Aims.We here apply the same methods to study the NLR of six Seyfert-1 galaxies and …

Size And Properties Of The Narrow-Line Region In Seyfert-2 Galaxies From Spatially-Resolved Optical Spectroscopy, N. Bennert, B. Jungwiert, S. Komossa, M. Haas, R. Chini

Physics

Context. While [O III] narrow-band imaging is commonly used to measure the size of the narrow-line regions (NLRs) in active galactic nuclei (AGNs), it can be contaminated by emission from surrounding starbursts. Recently, we have shown that long-slit spectroscopy provides a valuable alternative approach to probe the size in terms of AGN photoionisation. Moreover, several parameters of the NLR can be directly accessed. Aims. We here apply the same methods developed and described for the Seyfert-2 galaxy NGC 1386 to study the NLR of five other Seyfert-2 galaxies by using high-sensitivity spatially-resolved optical spectroscopy obtained at the VLT and the …

The Radio Structure Of Radio-Quiet Quasars, C. Leipski, H. Falcke, N. Bennert, S. Hüttenmeister

Physics

Aims. We investigate the radio emitting structures of radio-quiet active galactic nuclei with an emphasis on radio-quiet quasars to study their connection to Seyfert galaxies. Methods. We present and analyse high-sensitivity VLA radio continuum images of 14 radio-quiet quasars and six Seyfert galaxies. Results. Many of the low redshift radio-quiet quasars show radio structures that can be interpreted as jet-like outflows. However, the detection rate of extended radio structures on arcsecond scales among our sample decreases with increasing redshift and luminosity, most likely due to a lack of resolution. The morphologies of the detected radio emission indicate strong interactions of …

Size And Properties Of The Nlr In The Seyfert-2 Galaxy Ngc1386, N. Bennert, B. Jungwiert, S. Komossa

Physics

We study the narrow-line region (NLR) of the Seyfert-2 galaxy NGC 1386 by means of long-slit spectroscopy obtained with FORS1 at the VLT. We use the galaxy itself for subtracting the stellar template, applying reddening corrections to fit the stellar template to the spectra of the NLR. The continuum gets steadily redder towards the nucleus. The spatial distribution of the reddening derived from the Balmer decrement differs from the continuum reddening, indicating dust within the NLR with a varying column density along the line of sight. Using spatially resolved spectral diagnostics, we find a transition between central line ratios falling …

Size And Structure Of The Narrow-Line Region Of Quasars, Nicola Bennert, Heino Falcke, Hartmut Schulz, Andrew S. Wilson, Beverley J. Wills

Physics

We have observed the narrow-line regions (NLRs) of the seven brightest radio-quiet Palomar-Green (or Bright Quasar Survey) quasars (z < 0.5) with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope (HST). Linear-ramp filters were used to image the [O III] λ5007 line emission with 00455-01 pixel resolution. We find that the NLRs are very compact with typical extents of 2''-4''. Two quasars show compact filamentary structures similar to Seyfert NLRs. They may be related to radio outflows. Most interestingly, when including a sample of Seyfert galaxies observed with HST, we tentatively find that the size of the NLR is proportional to the square root …

Multiwavelength Monitoring Of The Narrow-Line Seyfert 1 Galaxy Arakelian 564. Iii. Optical Observations And The Optical--Uv--X-Ray Connection, O. Shemmer, P. Romano, R. Bertram, W. Brinkmann, S. Collier, K. A. Crowley, E. Detsis, A. V. Filippenko, C. Martin Gaskell, T. A. George, M. Gliozzi, M. E. Hiller, T. L. Jewell, Shai Kaspi, Elizabeth S. Klimek, M. H. Lannon, W D. Li, P. Martini, Smita Mathur, H. Negoro, Hagai Netzer, Iossif Papadakis, Ioannis Papamastorakis, Bradley M. Peterson, Bradley W. Peterson, Richard William Pogge, V. I. Pronik, Kenneth S. Rumstay, S. G. Sergeev, G. M. Stirpe, C. J. Taylor, R. R. Treffers, T. J. Turner, P. Uttley, Marianne Vestergaard, Kaspar Von Braun, R. M. Wagner, Z. Zheng

Department of Physics and Astronomy: Faculty Publications

We present the results of a 2 yr long optical monitoring program of the narrow-line Seyfert 1 galaxy Ark 564. The majority of this monitoring project was also covered by X-ray observations (RXT E), and for a period of ~50 days, we observed the galaxy in UV (HST) and X-rays (RXTE and ASCA) simultaneously with the ground-based observations. Rapid and large-amplitude variations seen in the X-ray band, on a daily and hourly timescale, were not detected at optical and UV wavelengths, which in turn exhibited much lower variability either on short (1 day) or long (several months) timescales. The only …