A&A 459, 745-757 (2006)
DOI: 10.1051/0004-6361:20065475
The Galaxy mass function up to z
in the GOODS-MUSIC
sample: into the epoch of formation of massive galaxies
A. Fontana1, S. Salimbeni1, A. Grazian1, E. Giallongo1, L. Pentericci1, M. Nonino2, F. Fontanot3, N. Menci1, P. Monaco3, 2, S. Cristiani2, E. Vanzella2, C. De Santis1, and S. Gallozzi1 1 INAF - Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio (RM), Italy
e-mail: fontana@mporzio.astro.it
2 INAF - Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, 34131 Trieste, Italy
3 Dipartimento di Astronomia, Università di Trieste, via G.B. Tiepolo 11, 34131 Trieste, Italy
(Received 21 April 2006 / Accepted 21 August 2006 )
Abstract
Aims.The goal of this work is to measure the evolution
of the Galaxy Stellar Mass Function and of the resulting Stellar Mass
Density up to redshift
4, in order to study the assembly of
massive galaxies in the high redshift Universe.
Methods.We have used the GOODS-MUSIC catalog, containing ~3000
Ks-selected galaxies with multi-wavelength coverage extending from the
U band to the Spitzer
m band, of which 27% have spectroscopic
redshifts and the remaining fraction have accurate photometric
redshifts. On this sample we have applied a standard fitting procedure to measure stellar masses. We compute the Galaxy Stellar Mass Function and the resulting Stellar
Mass Density up to redshift
4, taking into proper account the
biases and incompleteness effects.
Results.Within the well known trend of global decline of the Stellar Mass
Density with redshift, we show that the decline of the more massive
galaxies may be described by an exponential timescale of
6 Gyr up to
, and proceeds much faster thereafter, with an exponential timescale of
0.6 Gyr. We also show that there is some evidence for a differential evolution of the Galaxy
Stellar Mass Function, with low mass galaxies evolving faster than
more massive ones up to
and that the Galaxy Stellar
Mass Function remains remarkably flat (i.e. with a slope close to the
local one) up to
.
Conclusions.The observed behaviour of the Galaxy Stellar Mass Function is
consistent with a scenario where about 50% of present-day massive
galaxies formed at a vigorous rate in the epoch between
redshift 4 and 1.5, followed by a milder evolution until the
present-day epoch.
Key words: galaxies: distances and redshift -- galaxies: evolution -- galaxies: high-redshift -- galaxies: fundamental parameters -- galaxies: luminosity fuction, mass function
© ESO 2006

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