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Full-Text Articles in Physical Sciences and Mathematics
The Nature Of Lobal Qsos. Ii. Hst/Wfc3 Observations Reveal Host Galaxies Dominated By Mergers, Mariana S. Lazarova, Gabriela Canalizo, Mark Lacy, Wyatt Behn, Kaitlyn Raub, Vardha N. Bennert, Duncan Farrah
The Nature Of Lobal Qsos. Ii. Hst/Wfc3 Observations Reveal Host Galaxies Dominated By Mergers, Mariana S. Lazarova, Gabriela Canalizo, Mark Lacy, Wyatt Behn, Kaitlyn Raub, Vardha N. Bennert, Duncan Farrah
Physics
Low-ionization broad absorption line QSOs (LoBALs) are suspected to be merging systems in which extreme, active galactic nucleus-driven outflows have been triggered. Whether or not LoBALs are uniquely associated with mergers, however, has yet to be established. To characterize the morphologies of LoBALs, we present the first high-resolution morphological analysis of a volume-limited sample of 22 Sloan Digital Sky Survey (SDSS)-selected LoBALs at 0.5 < z < 0.6 from Hubble Space Telescope Wide Field Camera 3 observations. Host galaxies are resolved in 86% of the systems in F125W, which is sensitive to old stellar populations, while only 18% are detected in F475W, which traces young, unobscured stellar populations. Signs of recent or ongoing tidal interaction are present in 45%–64% of the hosts, including double nuclei, tidal tails, bridges, plumes, shells, and extended debris. Ongoing interaction with a companion is apparent in 27%−41% of the LoBALs, with as much as 1/3 of the sample representing late-stage mergers at projected nuclear separations <10 kpc. Detailed surface brightness modeling indicates that 41% of the hosts are bulge dominated while only 18% are disks. We discuss trends in various properties as a function of merger stage and parametric morphology. Notably, mergers are associated with slower, dustier winds than those seen in undisturbed/unresolved hosts. Our results favor an evolutionary scenario in which quasar-level accretion during various merger stages is associated with the observed outflows in low-z LoBALs. We discuss differences between LoBALs and FeLoBALs and show that selection via the traditional balnicity index would have excluded all but one of the mergers.
A Significant Excess In Major Merger Rate For Agns With The Highest Eddington Ratios At Z < 0.2, Victor Marian, Knud Jahnke, Irham Andika, Eduardo Bañados, Vardha N. Bennert, Seth Cohen, Bernd Husemann, Melanie Kaasinen, Anton M. Koekemoer, Mira Mechtley, Masafusa Onoue, Jan-Torge Schindler, Malte Schramm, Andreas Schulze, John D. Silverman, Irina Smirnova-Pinchukova, Arjen Van Der Wel, Carolin Villforth, Rogier A. Windhorst
A Significant Excess In Major Merger Rate For Agns With The Highest Eddington Ratios At Z < 0.2, Victor Marian, Knud Jahnke, Irham Andika, Eduardo Bañados, Vardha N. Bennert, Seth Cohen, Bernd Husemann, Melanie Kaasinen, Anton M. Koekemoer, Mira Mechtley, Masafusa Onoue, Jan-Torge Schindler, Malte Schramm, Andreas Schulze, John D. Silverman, Irina Smirnova-Pinchukova, Arjen Van Der Wel, Carolin Villforth, Rogier A. Windhorst
Physics
Observational studies are increasingly finding evidence against major mergers being the dominant mechanism responsible for triggering an active galactic nucleus (AGN). After studying the connection between major mergers and AGNs with the highest Eddington ratios at z = 2, we here expand our analysis to z < 0.2, exploring the same AGN parameter space. Using ESO VLT/FORS2 B-, V-, and color images, we examine the morphologies of 17 galaxies hosting AGNs with Eddington ratios , and 25 mass- and redshift-matched control galaxies. To match the appearance of the two samples, we add synthetic point sources to the inactive comparison galaxies. The combined sample of AGN and inactive galaxies was …
The American Astronomical Society, Find Out More The Institute Of Physics, Find Out More Where Do Quasar Hosts Lie With Respect To The Size–Mass Relation Of Galaxies?, John D. Silverman, Tommaso Treu, Xuheng Ding, Knud Jahnke, Vardha N. Bennert, Simon Birrer, Malte Schramm, Andreas Schulze, Jeyhan S. Kartaltepe, David B. Sanders, Renyue Cen
The American Astronomical Society, Find Out More The Institute Of Physics, Find Out More Where Do Quasar Hosts Lie With Respect To The Size–Mass Relation Of Galaxies?, John D. Silverman, Tommaso Treu, Xuheng Ding, Knud Jahnke, Vardha N. Bennert, Simon Birrer, Malte Schramm, Andreas Schulze, Jeyhan S. Kartaltepe, David B. Sanders, Renyue Cen
Physics
The evolution of the galaxy size–mass relation has been a puzzle for over a decade. High-redshift galaxies are significantly more compact than galaxies observed today at an equivalent mass, but how much of this apparent growth is driven by progenitor bias, minor mergers, secular processes, or feedback from active galactic nuclei (AGNs) is unclear. To help disentangle the physical mechanisms at work by addressing the latter, we study the size–Mstellar relation of 32 carefully selected broad-line AGN hosts at 1.2 < z < 1.7 (7.5 < log MBH < 8.5; Lbol/LEdd ≳ 0.1). Using the Hubble Space Telescope with multiband photometry and …
The Seoul National University Agn Monitoring Project. Ii. Blr Size And Black Hole Mass Of Two Agns, Suvendu Rakshit, Jong-Hak Woo, Elena Gallo, Edmund Hodges-Kluck, Jaejin Shin, Yiseul Jeon, Hyun-Jin Bae, Vivienne Baldassare, Hojin Cho, Wanjin Cho, Adi Foord, Daeun Kang, Wonseok Kang, Marios Karouzos, Minjin Kim, Taewoo Kim, Huynh Anh N. Lee, Daeseong Park, Hyun-Il Sung, Vardha N. Bennert, Matthew A. Malkan
The Seoul National University Agn Monitoring Project. Ii. Blr Size And Black Hole Mass Of Two Agns, Suvendu Rakshit, Jong-Hak Woo, Elena Gallo, Edmund Hodges-Kluck, Jaejin Shin, Yiseul Jeon, Hyun-Jin Bae, Vivienne Baldassare, Hojin Cho, Wanjin Cho, Adi Foord, Daeun Kang, Wonseok Kang, Marios Karouzos, Minjin Kim, Taewoo Kim, Huynh Anh N. Lee, Daeseong Park, Hyun-Il Sung, Vardha N. Bennert, Matthew A. Malkan
Physics
Active galactic nuclei (AGNs) show a correlation between the size of the broad line region and the monochromatic continuum luminosity at 5100 Å, allowing black hole mass estimation based on single-epoch spectra. However, the validity of the correlation is yet to be clearly tested for high-luminosity AGNs. We present the first reverberation mapping results of the Seoul National University AGN Monitoring Project (SAMP), which is designed to focus on luminous AGNs for probing the high end of the size–luminosity relation. We report time lag measurements of two AGNs, namely, 2MASS J10261389+5237510 and SDSS J161911.24+501109.2, using the light curves obtained over …
Studying The Potential Of The [Oii] Emission Line As A Surrogate For Stellar Velocity Dispersion In Active Galactic Nuclei, Edward F. Donohue
Studying The Potential Of The [Oii] Emission Line As A Surrogate For Stellar Velocity Dispersion In Active Galactic Nuclei, Edward F. Donohue
Physics
We study the emission profiles of 80 active galaxies to find a surrogate for stellar velocity dispersion. We focus on the width of the emission line of once ionized oxygen, [OII], and compare our results to previous work that used [OIII]. In previous research, [OIII] was found to be a good candidate for a surrogate for stellar velocity dispersion, but analysis of the line was complicated by the presence of wings caused by gas infall and outflow in the region. Emission lines with lower ionization levels, like [OII], are known to have less artificial line-broadening from wings. The study of …
A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. Ii. Measuring Stellar Velocity Dispersion In Active Galaxies, Chelsea E. Harris, Vardha N. Bennert, Matthew W. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. Ii. Measuring Stellar Velocity Dispersion In Active Galaxies, Chelsea E. Harris, Vardha N. Bennert, Matthew W. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
Physics
We derive spatially resolved stellar kinematics for a sample of 84 out of 104 observed local (0.02 < z < 0.09) galaxies hosting type-1 active galactic nuclei (AGNs), based on long-slit spectra obtained at the 10 m W. M. Keck-1 Telescope. In addition to providing central stellar velocity dispersions, we measure major axis rotation curves and velocity dispersion profiles using three separate wavelength regions, including the prominent Ca H&K, Mg Ib, and Ca II NIR stellar features. In this paper, we compare kinematic measurements of stellar velocity dispersion obtained for different apertures, wavelength regions, and signal-to-noise ratios, and provide recipes to cross-calibrate the measurements reducing systematic effects to the level of a few percent. We also provide simple recipes based on readily observable quantities such as global colors and Ca H&K equivalent width that will allow observers of high-redshift AGN hosts to increase the probability of obtaining reliable stellar kinematic measurements from unresolved spectra in the region surrounding the Ca H&K lines. In subsequent papers in this series, we will combine this unprecedented spectroscopic data set with surface photometry and black hole mass measurements to study in detail the scaling relations between host galaxy properties and black hole mass.
The Relation Between Black Hole Mass And Host Spheroid Stellar Mass Out To Z~2, Vardha N. Bennert, Matthew A. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
The Relation Between Black Hole Mass And Host Spheroid Stellar Mass Out To Z~2, Vardha N. Bennert, Matthew A. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
Physics
We combine Hubble Space Telescope images from the Great Observatories Origins Deep Survey with archival Very Large Telescope and Keck spectra of a sample of 11 X-ray-selected broad-line active galactic nuclei in the redshift range 1 < z < 2 to study the black-hole-mass-stellar-mass relation out to a look-back time of 10 Gyr. Stellar masses of the spheroidal component (M sph, ) are derived from multi-filter surface photometry. Black hole masses (M BH) are estimated from the width of the broad Mg II emission line and the 3000 Å nuclear luminosity. Comparing with a uniformly measured local sample and taking into account selection effects, we find evolution in the form M BH/M sph, (1 + z)1.96 …
Hubble Space Telescope Imaging Of Post-Starburst Quasars, S. L. Cales, M. S. Brotherton, Zhaohui Shang, Vardha N. Bennert, G. Canalizo, R. Stoll, R. Ganguly, D. Vanden Berk, C. Paul, A. Diamond-Stanic
Hubble Space Telescope Imaging Of Post-Starburst Quasars, S. L. Cales, M. S. Brotherton, Zhaohui Shang, Vardha N. Bennert, G. Canalizo, R. Stoll, R. Ganguly, D. Vanden Berk, C. Paul, A. Diamond-Stanic
Physics
We present images of 29 post-starburst quasars (PSQs) from a Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Wide Field Channel Snapshot program. These broadlined active galactic nuclei (AGNs) possess the spectral signatures of massive (M burst ~ 1010 M ☉), moderate-aged stellar populations (hundreds of Myr). Thus, their composite nature provides insight into the AGN-starburst connection. We measure quasar-to-host galaxy light contributions via semi-automated two-dimensional light profile fits of point-spread-function-subtracted images. We examine the host morphologies and model the separate bulge and disk components. The HST/ACS-F606W images reveal an equal number …
A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. I. Methodology And Results Of Pilot Study, Vardha Nicola Bennert, Matthew W. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. I. Methodology And Results Of Pilot Study, Vardha Nicola Bennert, Matthew W. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
Physics
We present high-quality Keck/LRIS long-slit spectroscopy of a pilot sample of 25 local active galaxies selected from the SDSS (0.02 ≤z ≤ 0.1; M BH>107 M ☉) to study the relations between black hole mass (M BH) and host-galaxy properties. We determine stellar kinematics of the host galaxy, deriving stellar-velocity dispersion profiles and rotation curves from three spectral regions (including CaH&K, MgIb triplet, and Ca II triplet). In addition, we perform surface photometry on SDSS images, using a newly developed code for joint multi-band analysis. BH masses are estimated from the width of the …
Sdss J1254+0846: A Binary Quasar Caught In The Act Of Merging, Paul J. Green, Adam D. Myers, Wayne A. Barkhouse, John S. Mulchaey, Vardha N. Bennert, Thomas J. Cox, Thomas L. Aldcroft
Sdss J1254+0846: A Binary Quasar Caught In The Act Of Merging, Paul J. Green, Adam D. Myers, Wayne A. Barkhouse, John S. Mulchaey, Vardha N. Bennert, Thomas J. Cox, Thomas L. Aldcroft
Physics
We present the first luminous, spatially resolved binary quasar that clearly inhabits an ongoing galaxy merger. SDSS J125455.09+084653.9 and SDSS J125454.87+084652.1 (SDSS J1254+0846 hereafter) are two luminous z = 0.44 radio-quiet quasars, with a radial velocity difference of just 215 km s–1, separated on the sky by 21 kpc in a disturbed host galaxy merger showing obvious tidal tails. The pair was targeted as part of a complete sample of binary quasar candidates with small transverse separations drawn from SDSS DR6 photometry. We present follow-up optical imaging which shows broad, symmetrical tidal arm features spanning some 75 kpc …
Cosmic Evolution Of Black Holes And Spheroids. Iv. The MBh - LSph Relation, Vardha N. Bennert, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan, Alexandre Le Bris, Matthew W. Auger, Sarah Gallagher, Roger D. Blandford
Cosmic Evolution Of Black Holes And Spheroids. Iv. The MBh - LSph Relation, Vardha N. Bennert, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan, Alexandre Le Bris, Matthew W. Auger, Sarah Gallagher, Roger D. Blandford
Physics
From high-resolution images of 23 Seyfert-1 galaxies at z = 0.36 and z = 0.57 obtained with the Near-Infrared Camera and Multi-Object Spectrometer on board the Hubble Space Telescope (HST), we determine host-galaxy morphology, nuclear luminosity, total host-galaxy luminosity, and spheroid luminosity. Keck spectroscopy is used to estimate black hole mass (M BH). We study the cosmic evolution of the M BH-spheroid luminosity (L sph) relation. In combination with our previous work, totaling 40 Seyfert-1 galaxies, the covered range in BH mass is substantially increased, allowing us to determine for the first time …
A Search For H2O Megamasers In High-Z Type-2 Active Galactic Nuclei, Vardha N. Bennert, Richard Barvainis, Christian Henkel, Robert Antonucci
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.
Evidence For Merger Remnants In Early-Type Host Galaxies Of Low-Redshift Qsos, Nicola Bennert, Gabriela Canalizo, Bruno Jungwiert, Alan Stockton, François Schweizer, Chien Y. Peng, Mark Lacy
Evidence For Merger Remnants In Early-Type Host Galaxies Of Low-Redshift Qsos, Nicola Bennert, Gabriela Canalizo, Bruno Jungwiert, Alan Stockton, François Schweizer, Chien Y. Peng, Mark Lacy
Physics
We present results from a pilot HST ACS deep imaging study in broadband V of five low-redshift QSO host galaxies classified in the literature as ellipticals. The aim of our study is to determine whether these early-type hosts formed at high redshift and have since evolved passively, or whether they have undergone relatively recent mergers that may be related to the triggering of the nuclear activity. We perform two-dimensional modeling of the light distributions to analyze the host galaxies' morphology. We find that, while each host galaxy is reasonably well fitted by a de Vaucouleurs profile, the majority of them …
Spectacular Shells In The Host Galaxy Of The Qso Mc2 1635+119, Gabriela Canalizo, Nicola Bennert, Bruno Jungwiert, Alan Stockton, François Schweizer, Mark Lacy, Chien Peng
Spectacular Shells In The Host Galaxy Of The Qso Mc2 1635+119, Gabriela Canalizo, Nicola Bennert, Bruno Jungwiert, Alan Stockton, François Schweizer, Mark Lacy, Chien Peng
Physics
We present deep HST ACS images and Keck spectroscopy of MC2 1635+119, a QSO hosted by a galaxy previously classified as an undisturbed elliptical galaxy. Our new images reveal dramatic shell structure indicative of a merger event in the relatively recent past. The brightest shells in the central regions of the host are distributed alternately in radius, with at least two distinct shells on one side of the nucleus and three on the other, out to a distance of ~13 kpc. The light within the five shells comprises ~6% of the total galaxy light. Lower surface brightness ripples or tails …
The Radio Structure Of Radio-Quiet Quasars, C. Leipski, H. Falcke, N. Bennert, S. Hüttenmeister
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 …
[O Iii] Profile Substructure In Radio-Quiet Quasars, C. Leipski, N. Bennert
[O Iii] Profile Substructure In Radio-Quiet Quasars, C. Leipski, N. Bennert
Physics
Interactions between the radio jet and the optical emission of the narrow-line region (NLR) are a well known phenomenon in Seyfert galaxies. Here, we present the study of possible jet-NLR interactions in five radio-quiet PG quasars with double or triple radio structure. High spatial and spectral resolution observations were carried out in the H-[O III] 5007 wavelength range. In all cases, there is evidence for [O III] profile substructure (shoulders, subpeaks, blueshifted "broad'' components) with different clarity. To measure the velocity, line width, intensity, and location of these [O III] components, several Gaussians were fitted. Often, the substructures are more …
Size And Structure Of The Narrow-Line Region Of Quasars, Nicola Bennert, Heino Falcke, Hartmut Schulz, Andrew S. Wilson, Beverley J. Wills
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 …