The relationship between star formation rates, local density and stellar mass up to z ∼ 3 in the GOODS NICMOS Survey

Autor: Alice Mortlock, Robert Chuter, Tim Weinzirl, Fernando Buitrago, Asa F. L. Bluck, Ruth Grützbauch, A. E. Bauer, C. J. Conselice, Shardha Jogee
Rok vydání: 2011
Předmět:
Zdroj: Monthly Notices of the Royal Astronomical Society. 418:938-948
ISSN: 0035-8711
Popis: We investigate the relation between star formation rates and local galaxy environment for a stellar-mass-selected galaxy sample in the redshift range 1.5 ≤z≤ 3. We use near-infrared imaging from an extremely deep Hubble Space Telescope survey, the GOODS NICMOS Survey (GNS), to measure local galaxy densities based on the nearest neighbour approach, while star formation rates are estimated from rest-frame ultraviolet fluxes. Due to our imaging depth, we can examine galaxies down to a colour-independent stellar mass completeness limit of log M*= 9.5 M⊙ at z∼ 3. We find a strong dependence of star formation activity on galaxy stellar mass over the whole redshift range, which does not depend on local environment. The average star formation rates are largely independent of local environment, apart from those in the highest relative overdensities. Galaxies in overdensities of a factor of >5 have on average lower star formation rates by a factor of 2–3, but only up to redshifts of z∼ 2. We do not see any evidence for active galactic nucleus activity influencing these relations. We also investigate the influence of the very local environment on star formation activity by counting neighbours within 30 kpc radius. This shows that galaxies with two or more close neighbours have on average significantly lower star formation rates as well as lower specific star formation rates up to z∼ 2.5. We suggest that this might be due to star formation quenching induced by galaxy merging processes.
Databáze: OpenAIRE
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