Color-Magnitude Relations of Active and Non-Active Galaxies in the Chandra Deep Fields: High-Redshift Constraints and Stellar-Mass Selection Effects - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: Abridged We extend color-magnitude relations for moderate-luminosity X-rayAGN hosts and non-AGN galaxies through the galaxy formation epoch in theChandra Deep Fields. We utilized analyses of color-magnitude diagrams CMDs toassess the role of moderate-luminosity AGNs in galaxy evolution. First, weconfirm some previous results and extend them to higher redshifts, e.g., thereis no apparent color bimodality for AGN hosts from z~0-2, but non-AGN galaxycolor bimodality exists up to z~3; most AGNs reside in massive hosts and theAGN fraction rises strongly toward higher stellar mass up to z~2-3; and thecolors of both AGN hosts and non-AGN galaxies become redder as the stellar massincreases up to z~2-3. Second, we point out that it is critical to usemass-matched samples to examine color-magnitude relations of AGN hosts andnon-AGN galaxies. We show that for mass-matched samples up to z~2-3, AGN hostslie in the same CMD region as non-AGN galaxies; i.e., there is no specificclustering of AGN hosts around the red sequence, the top of the blue cloud, orthe green valley in between. The AGN fraction ~10% is mostly independent ofhost-galaxy color, providing an indication of the duty cycle of SMBH growth intypical massive galaxies. These results are in contrast to those obtained withnon-mass-matched samples where there is apparent AGN clustering in the CMD andthe AGN fraction generally increases as the color becomes redder. We also find,for mass-matched samples, that the SFRs of AGN hosts are typically a factor of~2-3 larger than those of non-AGN galaxies at z~0-1, whereas this differencediminishes at z~1-3. Our results can be reasonably explained by two mainingredients, color-mass correlation and passive or secular evolution ofgalaxies; and thus tightly constrain any effects from moderate-luminosity AGNfeedback upon color-magnitude properties over the ~80% of cosmic time.



Autor: Y. Q. Xue, W. N. Brandt, B. Luo, D. A. Rafferty, D. M. Alexander, F. E. Bauer, B. D. Lehmer, D. P. Schneider, J. D. Silverman

Fuente: https://arxiv.org/







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