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Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/46079
Title: Herschel-ATLAS Galaxy Counts and High-redshift Luminosity Functions: The Formation of Massive Early-type Galaxies
Authors: Lapi, A.; Herranz, D.; López-Caniego, M.
Keywords: Galaxies: evolution
Galaxies: formation
Galaxies: high-redshift
Submilimeter: galaxies
Issue Date: Nov-2011
Publisher: Institute of Physics Publishing
American Astronomical Society
Citation: Astrophysical Journal 742(1): 24 (2011)
Abstract: Exploiting the Herschel-ATLAS Science Demonstration Phase (SDP) survey data, we have determined the luminosity functions (LFs) at rest-frame wavelengths of 100 and 250 micron and at several redshifts z>1, for bright sub-mm galaxies with star formation rates (SFR) >100 M_sun/yr. We find that the evolution of the comoving LF is strong up to z~2.5, and slows down at higher redshifts. From the LFs and the information on halo masses inferred from clustering analysis, we derived an average relation between SFR and halo mass (and its scatter). We also infer that the timescale of the main episode of dust-enshrouded star formation in massive halos (M_H>3*10^12 M_sun) amounts to ~7*10^8 yr. Given the SFRs, which are in the range 10^2-10^3 M_sun/yr, this timescale implies final stellar masses of order of 10^11-10^12 M_sun. The corresponding stellar mass function matches the observed mass function of passively evolving galaxies at z>1. The comparison of the statistics for sub-mm and UV selected galaxies suggests that the dust-free, UV bright phase, is >10^2 times shorter than the sub-mm bright phase, implying that the dust must form soon after the onset of star formation. Using a single reference Spectral Energy Distribution (SED; the one of the z~2.3 galaxy SMM J2135-0102), our simple physical model is able to reproduce not only the LFs at different redshifts > 1 but also the counts at wavelengths ranging from 250 micron to ~1 mm. Owing to the steepness of the counts and their relatively broad frequency range, this result suggests that the dispersion of sub-mm SEDs of z>1 galaxies around the reference one is rather small.
Description: Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.-- El Pdf del artículo es la version pre-print: arXiv:1108.3911v1.-- et al.
Publisher version (URL): http://dx.doi.org/10.1088/0004-637X/742/1/24
URI: http://hdl.handle.net/10261/46079
DOI: 10.1088/0004-637X/742/1/24
ISSN: 0004-637X
E-ISSN: 1538-4357
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