Caught in the Act: The Assembly of Massive Cluster Galaxies at z=1.62
| Autor: | Daniel H. McIntosh, Kim-Vy Tran, Amélie Saintonge, Dale D. Kocevski, Kyoung-Soo Lee, Ivelina Momcheva, Jennifer M. Lotz, Arjen van der Wel, Gregory Rudnick, Henry C. Ferguson, Anton M. Koekemoer, Yicheng Guo, Christopher N. A. Willmer, S. M. Faber, Norman A. Grogin, Casey Papovich |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Active galactic nucleus
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Stellar mass FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics DEEP SURVEY FIELD Hubble space telescope Galaxy formation and evolution STAR-FORMING GALAXIES clusters: general [galaxies] EXTRAGALACTIC LEGACY SURVEY RED SEQUENCE GALACTIC NUCLEUS Galaxy cluster Astrophysics::Galaxy Astrophysics Physics COSMIC cancer database interactions [galaxies] Astronomy Astronomy and Astrophysics Galaxy Red shift Physics and Astronomy Space and Planetary Science LUMINOSITY FUNCTION QUIESCENT GALAXIES HIGH-REDSHIFT STELLAR MASS DISTANT CLUSTER high-redshift [galaxies] Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | ASTROPHYSICAL JOURNAL |
| ISSN: | 0004-637X 1538-4357 |
| Popis: | We present the recent merger history of massive galaxies in a spectroscopically-confirmed proto-cluster at z=1.62. Using HST WFC3 near-infrared imaging from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), we select cluster galaxies and z ~ 1.6 field galaxies with M_star >= 3 x 10^10 M_sun, and determine the frequency of double nuclei or close companions with projected separations less than 20 kpc co-moving and stellar mass ratios between 1:1 and roughly 10:1. We find that four out of five spectroscopically-confirmed massive proto-cluster galaxies have double nuclei, and 42 +13/-25 % of all M_star >= 3 x 10^10 M_sun cluster candidates are either in close pair systems or have double nuclei. In contrast, only 4.5 +/- 2.6% of the field galaxies are in close pair/double nuclei systems. The implied merger rate per massive galaxy in the proto-cluster is 3-10 times higher than the merger rate of massive field galaxies at z ~ 1.6, depending upon the assumed mass ratios. Close pairs in the cluster have minor merger stellar mass ratios (M_primary:M_satellite ~ 6:1), while the field pairs are typically major mergers with stellar mass ratios between 1:1 and 4:1. At least half of the cluster mergers are dissipationless, as indicated by their red colors and low 24 micron fluxes. Two of the double-nucleated cluster members have X-ray detected AGN with L_x > 10^43 erg/s, and are strong candidates for dual or offset super-massive black holes. We conclude that the massive z = 1.62 proto-cluster galaxies are undergoing accelerated assembly relative to the field population, and discuss the implications for galaxy evolution in proto-cluster environments. 9 paper, 6 color figure, 1 table; submitted to ApJ |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|