Journal
ASTROPHYSICAL JOURNAL LETTERS
Volume 721, Issue 1, Pages L38-L42Publisher
IOP PUBLISHING LTD
DOI: 10.1088/2041-8205/721/1/L38
Keywords
galaxies: active; galaxies: high-redshift; X-rays: galaxies
Categories
Funding
- NSF [AST-0407295, AST-0449678, AST-0807570]
- Yale University
- National Aeronautics Space Administration [NAS8-03060, PF8-90055, PF9-00069]
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [0807570] Funding Source: National Science Foundation
Ask authors/readers for more resources
Using new, highly accurate photometric redshifts from the MUSYC medium-band survey in the Extended Chandra Deep Field-South (ECDF-S), we fit synthetic stellar population models to compare active galactic nucleus (AGN) host galaxies to inactive galaxies at 0.8 <= z <= 1.2. We find that AGN host galaxies are predominantly massive galaxies on the red sequence and in the green valley of the color-mass diagram. Because both passive and dusty galaxies can appear red in optical colors, we use rest-frame near-infrared colors to separate passively evolving stellar populations from galaxies that are reddened by dust. As with the overall galaxy population, similar to 25% of the red AGN host galaxies and similar to 75% of the green AGN host galaxies have colors consistent with young stellar populations reddened by dust. The dust-corrected rest-frame optical colors are the blue colors of star-forming galaxies, which imply that these AGN hosts are not passively aging to the red sequence. At z similar to 1, AGN activity is roughly evenly split between two modes of black hole growth: the first in passively evolving host galaxies, which may be heating up the galaxy's gas and preventing future episodes of star formation, and the second in dust-reddened young galaxies, which may be ionizing the galaxy's interstellar medium and shutting down star formation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available