Work

THE LICK AGN MONITORING PROJECT: VELOCITY-DELAY MAPS FROM THE MAXIMUM-ENTROPY METHOD FOR Arp 151

Year: 2010

Type: article

Abstract: 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 wings. Comparison with simple models identifies two classes that reproduce these features: free-falling gas and a half-illuminated disk with a hot spot at small radius on the receding lune. Symmetrically illuminated models with gas orbiting in an inclined disk or an isotropic distribution of randomly inclined circular orbits can reproduce the virial structure but not the observed asymmetry. Radial outflows are also largely ruled out by the observed asymmetry. A warped-disk geometry provides a physically plausible mechanism for the asymmetric illumination and hot spot features. Simple estimates show that a disk in the broad-line region of Arp 151 could be unstable to warping induced by radiation pressure. Our results demonstrate the potential power of detailed modeling combined with monitoring campaigns at higher cadence to characterize the gas kinematics and physical processes that give rise to the broad emission lines in active galactic nuclei.

Source: The Astrophysical Journal Letters

DOI: 10.1088/2041-8205/720/1/l46

Authors: 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

Institutions: University of California, Irvine, University of St Andrews, University of California, Santa Barbara, University of California, Riverside, University of California, Berkeley, University of California, Los Angeles, The University of Tokyo, Seoul National University

Language: English

Topic: Galaxies: Formation, Evolution, Phenomena

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: bronze

Funders: National Science Foundation, National Aeronautics and Space Administration, Space Telescope Science Institute, University of St Andrews, University of California, Santa Barbara, University of California, Riverside, University of California, Irvine, Science and Technology Facilities Council

Awards: Astrophysics in St Andrews/SUPA, CAREER: The Highest and Lowest- Mass Black Holes in the Nuclei of Nearby Galaxies, CAREER: Dark Matter and Black Holes Over Cosmic Time, G433322167, G4518818167, Triggering Mechanisms, Duty Cycles, and Black Hole Masses in QSOs, Supernovae In Nearby Galaxies: Discovery, Rates, and Detailed Studies, G58316358, G6273510985, Nearby Supernovae: Discovery at Birth and Follow-up Studies, G767601387, G8210229802

OpenAlex ID: W2027949865

FWCI: 5.591

Cites: 33

Cited by: 127

Related to: 10