THE IMPACT OF GALAXY INTERACTIONS ON ACTIVE GALACTIC NUCLEUS ACTIVITY IN zCOSMOS
- 17 November 2011
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 743 (1), 2
- https://doi.org/10.1088/0004-637x/743/1/2
Abstract
Close encounters between galaxies are expected to be a viable mechanism, as predicted by numerical simulations, by which accretion onto supermassive black holes can be initiated. To test this scenario, we construct a sample of 562 galaxies (M * > 2.5 × 1010 M ☉) in kinematic pairs over the redshift range 0.25 < z < 1.05 that are more likely to be interacting than a well-matched control sample of 2726 galaxies not identified as being in a pair, both from the zCOSMOS 20k spectroscopic catalog. Galaxies that harbor an active galactic nucleus (AGN) are identified on the basis of their X-ray emission (L 0.5-10 keV > 2 × 1042 erg s–1) detected by Chandra. We find a higher fraction of an AGN in galaxies in pairs relative to isolated galaxies of similar stellar mass. Our result is primarily due to an enhancement of AGN activity, by a factor of 1.9 (observed) and 2.6 (intrinsic), for galaxies in pairs of projected separation less than 75 kpc and line-of-sight velocity offset less than 500 km s–1. This study demonstrates that close kinematic pairs are conducive environments for black hole growth, either indicating a causal physical connection or an inherent relation, such as, to enhanced star formation. In the Appendix, we describe a method for estimating the intrinsic fractions of galaxies (either in pairs or the field) hosting an AGN with confidence intervals, and an excess fraction in pairs. We estimate that 17.8+8.4 –7.4% of all moderate-luminosity AGN activity takes place within galaxies undergoing early stages of interaction that leaves open the question as to what physical processes are responsible for fueling the remaining ~80% that may include late-stage mergers.Keywords
This publication has 44 references indexed in Scilit:
- On the Estimation of Confidence Intervals for Binomial Population Proportions in Astronomy: The Simplicity and Superiority of the Bayesian ApproachPublications of the Astronomical Society of Australia, 2011
- THE BULK OF THE BLACK HOLE GROWTH SINCEz∼ 1 OCCURS IN A SECULAR UNIVERSE: NO MAJOR MERGER-AGN CONNECTIONThe Astrophysical Journal, 2010
- Tracking the impact of environment on the galaxy stellar mass function up toz ~ 1 in the 10 k zCOSMOS sampleAstronomy & Astrophysics, 2010
- A RUNAWAY BLACK HOLE IN COSMOS: GRAVITATIONAL WAVE OR SLINGSHOT RECOIL?The Astrophysical Journal, 2010
- THEXMM-NEWTONWIDE-FIELD SURVEY IN THE COSMOS FIELD (XMM-COSMOS): DEMOGRAPHY AND MULTIWAVELENGTH PROPERTIES OF OBSCURED AND UNOBSCURED LUMINOUS ACTIVE GALACTIC NUCLEIThe Astrophysical Journal, 2010
- 1.75 h –1 kpc SEPARATION DUAL ACTIVE GALACTIC NUCLEI AT z = 0.36 IN THE COSMOS FIELDThe Astrophysical Journal, 2009
- GALAXY PAIRS IN THE SLOAN DIGITAL SKY SURVEY. I. STAR FORMATION, ACTIVE GALACTIC NUCLEUS FRACTION, AND THE LUMINOSITY/MASS-METALLICITY RELATIONThe Astronomical Journal, 2008
- Optical and Infrared Properties of the 2 Ms Chandra Deep Field North X-Ray SourcesThe Astronomical Journal, 2003
- Quasi‐Stellar Objects, Ultraluminous Infrared Galaxies, and MergersThe Astrophysical Journal, 2001
- Hubble Space TelescopeImages of a Sample of 20 Nearby Luminous QuasarsThe Astrophysical Journal, 1997