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California Polytechnic State University, San Luis Obispo

Seyfert

Articles 1 - 17 of 17

Full-Text Articles in Physics

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 Jan 2013

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 Oct 2012

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 Mar 2012

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 or dispersion, σ) and of the AGN continuum luminosity at 5100 Å (L 5100). From the distribution of the "virial products" ( FWHM 2 L 0.5 ...


Megamaser Detection And Nuclear Obscuration In Seyfert Galaxies, M. Ramolla, M. Hass, V. N. Bennert, R. Chini Jun 2011

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 ...


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 Nov 2010

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 Sep 2010

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 Jun 2010

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 here the ...


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 Jun 2010

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*) 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 obtained with the ...


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 Nov 2009

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 objects ...


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 Nov 2009

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 2 ...


A Search For H2O Megamasers In High-Z Type-2 Active Galactic Nuclei, Vardha N. Bennert, Richard Barvainis, Christian Henkel, Robert Antonucci Apr 2009

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 Dec 2008

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 ...


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 Sep 2006

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 compare our ...


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 Sep 2006

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 Aug 2006

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 Feb 2006

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 Aug 2002

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 of the [O ...