Bibcode
Guglielmo, V.; Poggianti, Bianca M.; Moretti, Alessia; Fritz, Jacopo; Calvi, R.; Vulcani, Benedetta; Fasano, Giovanni; Paccagnella, Angela
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 450, Issue 3, p.2749-2763
Advertised on:
7
2015
Citations
58
Refereed citations
55
Description
We analyse the star formation history (SFH) of galaxies as a function of
present-day environment, galaxy stellar mass and morphology. The SFH is
derived by means of a non-parametric spectrophotometric model applied to
individual galaxies at z ˜ 0.04-0.1 in the WIde-field Nearby
Galaxy-cluster Survey (WINGS) clusters and the Padova Millennium Galaxy
and Group Catalogue (PM2GC) field. The field reconstructed evolution of
the star formation rate density (SFRD) follows the values observed at
each redshift, except at z > 2, where our estimate is ˜1.7
× higher than the high-z observed value. The slope of the SFRD
decline with time gets progressively steeper going from low-mass to
high-mass haloes. The decrease of the SFRD since z = 2 is due to (1)
quenching - 50 per cent of the SFRD in the field and 75 per cent in
clusters at z > 2 originated in galaxies that are passive today - and
(2) the fact that the average SFR of today's star-forming galaxies has
decreased with time. We quantify the contribution to the SFRD(z) of
galaxies of today's different masses and morphologies. The current
morphology correlates with the current star formation activity but is
irrelevant for the past stellar history. The average SFH depends on
galaxy mass, but galaxies of a given mass have different histories
depending on their environment. We conclude that the variation of the
SFRD(z) with environment is not driven by different distributions of
galaxy masses and morphologies in clusters and field, and must be due to
an accelerated formation in high-mass haloes compared to low-mass ones
even for galaxies that will end up having the same galaxy mass today.