2007A&A...468...33E


C.D.S. - SIMBAD4 rel 1.7 - 2019.09.23CEST05:57:55

2007A&A...468...33E - Astronomy and Astrophysics, volume 468, 33-48 (2007/6-2)

The reversal of the star formation-density relation in the distant universe.

ELBAZ D., DADDI E., LE BORGNE D., DICKINSON M., ALEXANDER D.M., CHARY R.-R., STARCK J.-L., BRANDT W.N., KITZBICHLER M., MacDONALD E., NONINO M., POPESSO P., STERN D. and VANZELLA E.

Abstract (from CDS):

We study the relationship between the local environment of galaxies and their star formation rate (SFR) in the Great Observatories Origins Deep Survey, GOODS, at z∼1. We use ultradeep imaging at 24µm with the MIPS camera onboard Spitzer to determine the contribution of obscured light to the SFR of galaxies over the redshift range 0.8≤z≤1.2. Accurate galaxy densities are measured thanks to the large sample of ∼1200 spectroscopic redshifts with high (∼70%) spectroscopic completeness. Morphology and stellar masses are derived from deep HST-ACS imaging, supplemented by ground based imaging programs and photometry from the IRAC camera onboard Spitzer. We show that the star formation-density relation observed locally was reversed at z∼1: the average SFR of an individual galaxy increased with local galaxy density when the universe was less than half its present age. Hierarchical galaxy formation models (simulated lightcones from the Millennium model) predicted such a reversal to occur only at earlier epochs (z>2) and at a lower level. We present a remarkable structure at z∼1.016, containing X-ray traced galaxy concentrations, which will eventually merge into a Virgo-like cluster. This structure illustrates how the individual SFR of galaxies increases with density and shows that it is the ∼1-2Mpc scale that affects most the star formation in galaxies at z∼1. The SFR of z∼1 galaxies is found to correlate with stellar mass suggesting that mass plays a role in the observed star formation-density trend. However the specific SFR (=SFR/M*) decreases with stellar mass while it increases with galaxy density, which implies that the environment does directly affect the star formation activity of galaxies. Major mergers do not appear to be the unique or even major cause for this effect since nearly half (46%) of the luminous infrared galaxies (LIRGs) at z∼1 present the HST-ACS morphology of spirals, while only a third present a clear signature of major mergers. The remaining galaxies are divided into compact (9%) and irregular (14%) galaxies. Moreover, the specific SFR of major mergers is only marginally stronger than that of spirals. These findings constrain the influence of the growth of large-scale structures on the star formation history of galaxies. Reproducing the SFR-density relation at z∼1 is a new challenge for models, requiring a correct balance between mass assembly through mergers and in-situ star formation at early epochs.

Abstract Copyright:

Journal keyword(s): cosmology: observations - Galaxy: formation - Galaxy: evolution - galaxies: starburst - infrared: galaxies - cosmology: large-scale structure of Universe

Simbad objects: 14

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Number of rows : 14

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 NAME Chandra Deep Field-South reg 03 32 28.0 -27 48 30           ~ 1743 1
2 NAME GOODS Southern Field reg 03 32 28.0 -27 48 30           ~ 988 1
3 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5198 6
4 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5620 0
5 SHARDS J123644.39+621133.2 AGN 12 36 44.396 +62 11 33.17 26.48 25.0 24.15 21.96 21.60 ~ 79 0
6 CXOHDFN J123645.0+621142 X 12 36 45.0 +62 11 42           ~ 4 0
7 NAME Chandra Deep Field-North reg 12 36.8 +62 13           ~ 598 0
8 NAME Hubble Deep Field reg 12 36 49.5 +62 12 58           ~ 1800 1
9 NAME GOODS-N Field reg 12 36 55.0 +62 14 15           ~ 869 1
10 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4073 2
11 ACO 1689 ClG 13 11 29.5 -01 20 28           ~ 997 0
12 NAME Extended Groth Strip reg 14 19 +52.8           ~ 536 0
13 IC 4553 SyG 15 34 57.22396 +23 30 11.6084   14.76 13.88     ~ 2606 4
14 NAME SDSS-SN 15207 SN* 20 58 43.45 +01 02 47.0           ~ 3 0

    Equat.    Gal    SGal    Ecl

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2019.09.23-05:57:55

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