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Articles 91 - 120 of 132
Full-Text Articles in Physics
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 Study Of The Orbits Of The Logarithmic Potential For Galaxies, Sree Ram Valluri, Paul Wiegert, John Drozd, Matt Dasilva
A Study Of The Orbits Of The Logarithmic Potential For Galaxies, Sree Ram Valluri, Paul Wiegert, John Drozd, Matt Dasilva
Physics and Astronomy Publications
The logarithmic potential is of great interest and relevance in the study of the dynamics of galaxies. Some small corrections to the work of Contopoulos & Seimenis (1990) who used the method of Prendergast (1982) to find periodic orbits and bifurca- tions within such a potential are presented. The solution of the orbital radial equation for the purely radial logarithmic potential is then considered using the p-ellipse (pre- cessing ellipse) method pioneered by Struck (2006). This differential orbital equation is a special case of the generalized Burgers equation. The apsidal angle is also deter- mined, both numerically as well as …
The Mass Of The Black Hole In Arp 151 From Bayesian Modeling Of Reverberation Mapping Data, Brendon J. Brewer, Tommaso Treu, Anna Pancoast, Aaron J. Barth, Vardha N. Bennert, Misty C. Bentz, Alexei V. Filippenko, Jenney E. Greene, Matthew A. Malkan, Jong-Hak Woo
The Mass Of The Black Hole In Arp 151 From Bayesian Modeling Of Reverberation Mapping Data, Brendon J. Brewer, Tommaso Treu, Anna Pancoast, Aaron J. Barth, Vardha N. Bennert, Misty C. Bentz, Alexei V. Filippenko, Jenney E. Greene, Matthew A. Malkan, Jong-Hak Woo
Physics
Supermassive black holes are believed to be ubiquitous at the centers of galaxies. Measuring their masses is extremely challenging yet essential for understanding their role in the formation and evolution of cosmic structure. We present a direct measurement of the mass of a black hole in an active galactic nucleus (Arp 151) based on the motion of the gas responsible for the broad emission lines. By analyzing and modeling spectroscopic and photometric time series, we find that the gas is well described by a disk or torus with an average radius of 3.99 ± 1.25 light days and an opening …
Forecasting The Cosmological Constraints With Anisotropic Baryon Acoustic Oscillations From Multipole Expansion, Atsushi Taruya, Shun Saito, Takahiro Nishimichi
Forecasting The Cosmological Constraints With Anisotropic Baryon Acoustic Oscillations From Multipole Expansion, Atsushi Taruya, Shun Saito, Takahiro Nishimichi
Physics Faculty Research & Creative Works
Baryon acoustic oscillations imprinted in the galaxy power spectrum can be used as a standard ruler to determine the angular diameter distance and Hubble parameter from high-redshift galaxies. Combining redshift distortion effect which apparently distorts the galaxy clustering pattern, we can also constrain the growth rate of large-scale structure formation. Usually, future forecasts for constraining these parameters from galaxy redshift surveys are made with the full 2D power spectrum characterized as a function of wave number k and directional cosine µ between line-of-sight direction and wave vector, i.e., P(k,µ). Here, we apply the multipole expansion to the full 2D power …
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 …
Accuracy Of The Thin-Lens Approximation In Strong Lensing By Smoothly Truncated Dark Matter Haloes, S. Frittelli, Thomas Kling
Accuracy Of The Thin-Lens Approximation In Strong Lensing By Smoothly Truncated Dark Matter Haloes, S. Frittelli, Thomas Kling
Physics Faculty Publications
The accuracy of mass estimates by gravitational lensing using the thin-lens approximation applied to Navarro–Frenk–White mass models with a soft truncation mechanism recently proposed by Baltz, Marshall and Oguri is studied. The gravitational lens scenario considered is the case of the inference of lens mass from the observation of Einstein rings (strong lensing). It is found that the mass error incurred by the simplifying assumption of thin lenses is below 0.5 per cent. As a byproduct, the optimal tidal radius of the soft truncation mechanism is found to be at most 10 times the virial radius of the mass model.
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
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 Energetics Of Molecular Gas In Ngc 891 From H2 And Far-Infrared Spectroscopy, G. J. Stacey, Vassilis Charmandaris, F. Boulanger, Yanling Wu, F. Combes, S. J. U. Higdon, J. D. T. Smith, T. Nikola
The Energetics Of Molecular Gas In Ngc 891 From H2 And Far-Infrared Spectroscopy, G. J. Stacey, Vassilis Charmandaris, F. Boulanger, Yanling Wu, F. Combes, S. J. U. Higdon, J. D. T. Smith, T. Nikola
Department of Physics and Astronomy Faculty Publications
We have studied the molecular hydrogen energetics of the edge-on spiral galaxy NGC?891, using a 34 position map in the lowest three pure rotational H2 lines observed with the Spitzer Infrared Spectrograph. The S(0), S(1), and S(2) lines are bright with an extinction-corrected total luminosity of ~2.8 × 107 L ?, or 0.09% of the total-infrared luminosity of NGC?891. The H2 line ratios are nearly constant along the plane of the galaxy?we do not observe the previously reported strong drop-off in the S(1)/S(0) line intensity ratio in the outer regions of the galaxy, so …
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
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 …
Baryon Acoustic Oscillations In 2d: Modeling Redshift-Space Power Spectrum From Perturbation Theory, Atsushi Taruya, Takahiro Nishimichi, Shun Saito
Baryon Acoustic Oscillations In 2d: Modeling Redshift-Space Power Spectrum From Perturbation Theory, Atsushi Taruya, Takahiro Nishimichi, Shun Saito
Physics Faculty Research & Creative Works
We present an improved prescription for the matter power spectrum in redshift space taking proper account of both nonlinear gravitational clustering and redshift distortion, which are of particular importance for accurately modeling baryon acoustic oscillations (BAOs). Contrary to the models of redshift distortion phenomenologically introduced but frequently used in the literature, the new model includes the corrections arising from the nonlinear coupling between the density and velocity fields associated with two competitive effects of redshift distortion, i.e., Kaiser and Finger-of-God effects. Based on the improved treatment of perturbation theory for gravitational clustering, we compare our model predictions with the monopole …
Herschel Photometry Of Brightest Cluster Galaxies In Cooling Flow Clusters, A. C. Edge, J. B. R. Oonk, R. Mittal, S. W. Allen, S. A. Baum, H. Böhringer, J. N. Bregman, M. N. Bremer, F. Combes, C. S. Crawford, M. Donahue, E. Egami, A. C. Fabian, Gary J. Ferland, S. L. Hamer, N. A. Hatch, W. Jaffe, R. M. Johnstone, B. R. Mcnamara, C. P. O'Dea, P. Popesso, A. C. Quillen, P. Salomé, C. L. Sarazin, G. M. Voit, R. J. Wilman, M. W. Wise
Herschel Photometry Of Brightest Cluster Galaxies In Cooling Flow Clusters, A. C. Edge, J. B. R. Oonk, R. Mittal, S. W. Allen, S. A. Baum, H. Böhringer, J. N. Bregman, M. N. Bremer, F. Combes, C. S. Crawford, M. Donahue, E. Egami, A. C. Fabian, Gary J. Ferland, S. L. Hamer, N. A. Hatch, W. Jaffe, R. M. Johnstone, B. R. Mcnamara, C. P. O'Dea, P. Popesso, A. C. Quillen, P. Salomé, C. L. Sarazin, G. M. Voit, R. J. Wilman, M. W. Wise
Physics and Astronomy Faculty Publications
The dust destruction timescales in the cores of clusters of galaxies are relatively short given their high central gas densities. However, substantial mid-infrared and sub-mm emission has been detected in many brightest cluster galaxies. In this letter we present Herschel PACS and SPIRE photometry of the brightest cluster galaxy in three strong cooling flow clusters, A1068, A2597 and Zw3146. This photometry indicates that a substantial mass of cold dust is present (> 3×107 M⊙) at temperatures significantly lower (20–28 K) than previously thought based on limited MIR and/or sub-mm results. The mass and temperature of the dust appear …
Herschel Observations Of Fir Emission Lines In Brightest Cluster Galaxies, A. C. Edge, J. B. R. Oonk, R. Mittal, S. W. Allen, S. A. Baum, H. Böhringer, J. N. Bregman, M. N. Bremer, F. Combes, C. S. Crawford, M. Donahue, E. Egami, A. C. Fabian, Gary J. Ferland, S. L. Hamer, N. A. Hatch, W. Jaffe, R. M. Johnstone, B. R. Mcnamara, C. P. O'Dea, P. Popesso, A. C. Quillen, P. Salomé, C. L. Sarazin, G. M. Voit, R. J. Wilman, M. W. Wise
Herschel Observations Of Fir Emission Lines In Brightest Cluster Galaxies, A. C. Edge, J. B. R. Oonk, R. Mittal, S. W. Allen, S. A. Baum, H. Böhringer, J. N. Bregman, M. N. Bremer, F. Combes, C. S. Crawford, M. Donahue, E. Egami, A. C. Fabian, Gary J. Ferland, S. L. Hamer, N. A. Hatch, W. Jaffe, R. M. Johnstone, B. R. Mcnamara, C. P. O'Dea, P. Popesso, A. C. Quillen, P. Salomé, C. L. Sarazin, G. M. Voit, R. J. Wilman, M. W. Wise
Physics and Astronomy Faculty Publications
The question of how much gas cools in the cores of clusters of galaxies has been the focus of many, multiwavelength studies in the past 30 years. In this letter we present the first detections of the strongest atomic cooling lines, [Cii], [Oi] and [Nii] in two strong cooling flow clusters, A1068 and A2597, using Herschel-PACS. These spectra indicate that the substantial mass of cold molecular gas (> 109 M⊙) known to be present in these systems is being irradiated by intense UV radiation, most probably from young stars. The line widths of these FIR lines …
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
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
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 …
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 …
Dark Matter Halos And Evolution Of Bars In Disk Galaxies: Varying Gas Fraction And Gas Spatial Resolution, Jorge Villa-Vargas, Isaac Schlosman, Clayton Heller
Dark Matter Halos And Evolution Of Bars In Disk Galaxies: Varying Gas Fraction And Gas Spatial Resolution, Jorge Villa-Vargas, Isaac Schlosman, Clayton Heller
Jorge Villa-Vargas
We conduct numerical experiments by evolving gaseous/stellar disks embedded in live dark matter halos aiming at quantifying the effect of gas spatial resolution and gas content on the bar evolution. Three model sequences have been constructed using different resolutions, and the gas fraction has been varied along each sequence within the range of fg = 0%-50%, but keeping the disk and halo properties unchanged. We find that the spatial resolution becomes important with an increase in the gas content. For the higher resolution model sequences, we observe a bimodal behavior in the bar evolution with respect to the gas …
Discovery Of A Young L Dwarf Binary, Sdss224953.47+004404.6ab, Katelyn N. Allers, Michael C. Liu, Trent J. Dupuy, Michael C. Cushing
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.
Nonlinear Evolution Of Baryon Acoustic Oscillations From Improved Perturbation Theory In Real And Redshift Spaces, Atsushi Taruya, Takahiro Nishimichi, Shun Saito, Takashi Hiramatsu
Nonlinear Evolution Of Baryon Acoustic Oscillations From Improved Perturbation Theory In Real And Redshift Spaces, Atsushi Taruya, Takahiro Nishimichi, Shun Saito, Takashi Hiramatsu
Physics Faculty Research & Creative Works
We study the nonlinear evolution of baryon acoustic oscillations in the matter power spectrum and correlation function from the improved perturbation theory (PT). Based on the framework of renormalized PT, which provides a nonperturbative way to treat the gravitational clustering of large-scale structure, we apply the closure approximation that truncates the infinite series of loop contributions at one-loop order, and obtain a closed set of integral equations for power spectrum and nonlinear propagator. The resultant integral expressions are basically equivalent to those previously derived in the form of evolution equations, and they keep important nonperturbative properties which can dramatically improve …
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
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
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 …
Pah Emission From Ultraluminous Infrared Galaxies, V. Desai, L. Armus, H. W. W. Spoon, Vassilis Charmandaris, J. Bernard-Salas, B. R. Brandl, D. Farrah, B.T. Soifer, H. I. Teplitz, P. M. Ogle, D. Devost, Sarah J.U. Higdon, J. A. Marshall, J. R. Houck
Pah Emission From Ultraluminous Infrared Galaxies, V. Desai, L. Armus, H. W. W. Spoon, Vassilis Charmandaris, J. Bernard-Salas, B. R. Brandl, D. Farrah, B.T. Soifer, H. I. Teplitz, P. M. Ogle, D. Devost, Sarah J.U. Higdon, J. A. Marshall, J. R. Houck
Department of Physics and Astronomy Faculty Publications
We explore the relationships between the Polycyclic Aromatic Hydrocarbon (PAH) feature strengths, mid-infrared continuum luminosities, far-infrared spectral slopes, optical spectroscopic classifications, and silicate optical depths within a sample of 107 ULIRGs observed with the Infrared Spectrograph on the Spitzer Space Telescope. The detected 6.2 µm PAH equivalent widths (EQWs) in the sample span more than two orders of magnitude (∼0.006–0.8 µm), and ULIRGs with HII-like optical spectra or steep far-infrared spectral slopes (S25/S60 < 0.2) typically have 6.2 µm PAH EQWs that are half that of lower-luminosity starbursts. A significant fraction (∼40–60%) of HII-like, LINER-like, and cold ULIRGs have very weak PAH EQWs. Many of these ULIRGs also have large (τ9.7 > 2.3) silicate optical depths. The far-infrared spectral slope is strongly correlated with PAH EQW, but not with silicate optical depth. In addition, the PAH EQW decreases with …
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.
Hubble Space Telescope Morphologies Of Z ~ 2 Dust Obscured Galaxies. I. Power-Law Sources, R.S. Bussman, Arjun Dey, J. Lotz, Lee Armus, Kate Brand, Michael J. I. Brown, Vandana Desai, Peter Eisenhardt, James L. Higdon, Sarah J.U. Higdon, B. T. Jannuzi, Emeric Le Floc'h, J. Melbourne, B. T. Soifer, Daniel Weedman
Hubble Space Telescope Morphologies Of Z ~ 2 Dust Obscured Galaxies. I. Power-Law Sources, R.S. Bussman, Arjun Dey, J. Lotz, Lee Armus, Kate Brand, Michael J. I. Brown, Vandana Desai, Peter Eisenhardt, James L. Higdon, Sarah J.U. Higdon, B. T. Jannuzi, Emeric Le Floc'h, J. Melbourne, B. T. Soifer, Daniel Weedman
Department of Physics and Astronomy Faculty Publications
We present high spatial resolution optical and near-infrared imaging obtained using the ACS, WFPC2 and NICMOS cameras aboard the Hubble Space Telescope of 31 24µm–bright z ≈ 2 Dust Obscured Galaxies (DOGs) identified in the Bo¨otes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral energy distributions dominated by a power-law component suggestive of an AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame UV or optical wavelengths. The observed V − H and I − H colors of the extended components are 0.2−3 …
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
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 …
Radio And Infrared Selected Optically Invisible Sources In The Boötes Ndwfs, James L. Higdon, Sarah J.U. Higdon, Steven P. Willner, Michael J. I. Brown, D. Stern, Emeric Le Floc'h, Peter Eisenhardt
Radio And Infrared Selected Optically Invisible Sources In The Boötes Ndwfs, James L. Higdon, Sarah J.U. Higdon, Steven P. Willner, Michael J. I. Brown, D. Stern, Emeric Le Floc'h, Peter Eisenhardt
Department of Physics and Astronomy Faculty Publications
We have combined data from the NOAO Deep Wide-Field Survey in Bo¨otes and the Spitzer Space Telescope to determine basic properties for sixteen optically “invisible” MIPS 24 µm (OIMS) and thirty-five optically “invisible” radio (OIRS) sources, including their spectral energy distributions (SED) and luminosities. Most OIMSs possess steep power-law SEDs over λrest = 1 − 10 µm, indicating the presence of obscured AGN in agreement with Spitzer spectroscopy. These objects are extremely luminous at rest-frame near and mid-IR (νLν(5 µm) ≈ 1038 − 1039 W), consistent with accretion near the Eddington limit and further implying that they host buried QSOs. …
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 …
Spitzer Observations Of Tidal Dwarf Galaxies, Sarah J.U. Higdon, James L. Higdon
Spitzer Observations Of Tidal Dwarf Galaxies, Sarah J.U. Higdon, James L. Higdon
Department of Physics and Astronomy Faculty Publications
We present Spitzer observations of Tidal Dwarf Galaxies (TDGs) in three interacting systems: NGC 5291, Arp 105 & Stephan’s Quintet. The spectra show bright emission from polyaromatic hydrocarbons (PAHs), nebular lines and warm molecular hydrogen, characteristic of recent episodes of star formation. The PAH emission that falls in the IRAC 8.0 µm band leads to the TDGs having an extremely red IRAC color, with [4.5] − [8.0] > 3. The emission from PAHs is characterized by a model with mainly neutral 100-C PAH atoms.
A Significant Population Of Very Luminous Dust-Obscured Galaxies At Redshift Z ~ 2, Arjun Dey, B.T. Soifer, Vandana Desai, Kate Brand, Emeric Le Floc'h, Michael J. I. Brown, Buell T. Jannuzi, Lee Armus, R. Shane Bussmann, Mark Brodwin, Chao Bian, Peter Eisenhardt, Sarah J.U. Higdon, Daniel Weedman, S. P. Willner
A Significant Population Of Very Luminous Dust-Obscured Galaxies At Redshift Z ~ 2, Arjun Dey, B.T. Soifer, Vandana Desai, Kate Brand, Emeric Le Floc'h, Michael J. I. Brown, Buell T. Jannuzi, Lee Armus, R. Shane Bussmann, Mark Brodwin, Chao Bian, Peter Eisenhardt, Sarah J.U. Higdon, Daniel Weedman, S. P. Willner
Department of Physics and Astronomy Faculty Publications
Observations with the Spitzer Space Telescope have recently revealed a significant population of high-redshift (z ∼ 2) dust-obscured galaxies (DOGs) with large (rest-frame) mid-infrared to ultraviolet luminosity ratios. Due to their optical faintness, these galaxies have been previously missed in traditional optical studies of the distant universe. We present a simple method for selecting this high-redshift population based solely on the ratio of the observed mid-infrared 24µm to optical R-band flux density. We apply this method to observations of the ≈ 8.6 deg2 Bo¨otes Field of the NOAO Deep Wide-Field Survey, and uncover ≈2,600 DOG candidates (i.e., a surface density …
Stability Of Hickson Groups Of Galaxies, Ibrahim Selim, Naseer Iqbal
Stability Of Hickson Groups Of Galaxies, Ibrahim Selim, Naseer Iqbal
Turkish Journal of Physics
In this work we have used the Viril theorem to investigate the dynamical stability of Hickson compact groups of galaxies. The average luminous mass of the galaxies member is approximately 1.3 \times 0^{11} M_{\odot} and average total luminous mass of group is approximately 4.6 \times 0^{11} M_{\odot}. The virial theorem has used to estimate the virial mass. The average Virial mass of group of galaxies is approximately 6.3 \times 0^{13} M_{\odot} This is attributed to the presence of large amount of dark matter which is more than 90% in this group. Hickson compact groups of galaxies are unstable system due …
Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula
Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula
Department of Physics and Astronomy Faculty Publications
We investigate formation and evolution of galactic disks immersed in assembling live DM halos. Models have been evolved from cosmological initial conditions and represent the collapse of an isolated density perturbation. The baryons include gas participating in star formation (SF) and stars with the energy feedback onto the ISM. We find that (1) the triaxial halo figure tumbling is insignificant and the angular momentum (J) is channeled into the internal circulation, while the baryonic collapse is stopped by the centrifugal barrier; (2) density response of the (disk) baryons is out of phase with DM, thus washing out the …