Bibcode
Oliver, Seb; Frost, M.; Farrah, D.; Gonzalez-Solares, E.; Shupe, D. L.; Henriques, B.; Roseboom, I.; Alonso-Luis, A.; Babbedge, T. S. R.; Frayer, D.; Lencz, C.; Lonsdale, C. J.; Masci, F.; Padgett, D.; Polletta, M.; Rowan-Robinson, M.; Siana, B.; Smith, H. E.; Surace, J. A.; Vaccari, M.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 405, Issue 4, pp. 2279-2294.
Fecha de publicación:
7
2010
Número de citas
114
Número de citas referidas
112
Descripción
We use the Spitzer Wide-area InfraRed Extragalactic Legacy Survey
(SWIRE) to explore the specific star formation activity of galaxies and
their evolution near the peak of the cosmic far-infrared (FIR)
background at 70 and 160 μm. We use a stacking analysis to determine
the mean FIR properties of well-defined subsets of galaxies at flux
levels well below the FIR catalogue detection limits of SWIRE and other
Spitzer surveys. We tabulate the contribution of different subsets of
galaxies to the FIR background at 70 and 160 μm. These long
wavelengths provide a good constraint on the bolometric obscured
emission. The large area provides good constraints at low z and in finer
redshift bins than previous work. At all redshifts we find that the
specific FIR luminosity decreases with increasing mass, following a
trend LFIR/M* ~ Mβ*
with β = -0.38 +/- 0.14. This is a more continuous change than
expected from the De Lucia & Blaizot semi-analytic model suggesting
modifications to the feedback prescriptions. We see an increase in the
specific FIR luminosity by about a factor of ~100 from 0 < z < 2
and find that the specific FIR luminosity evolves as (1 +
z)α with α = 4.4 +/- 0.3 for galaxies with 10.5
< log10 M*/Msolar <= 12. This is
considerably steeper than the De Lucia & Blaizot semi-analytic model
(α ~ 2.5). When separating galaxies into early and late types on
the basis of the optical/IR spectral energy distributions we find that
the decrease in specific FIR luminosity with stellar mass is stronger in
early-type galaxies (β ~ -0.46), while late-type galaxies exhibit a
flatter trend (β ~ -0.15). The evolution is strong for both classes
but stronger for the early-type galaxies. The early types show a trend
of decreasing strength of evolution as we move from lower to higher
masses while the evolution of the late-type galaxies has little
dependence on stellar mass. We suggest that in late-type galaxies we are
seeing a consistently declining specific star formation rate α =
3.36 +/- 0.16 through a common phenomenon, for example, exhaustion of
gas supply, i.e. not systematically dependent on the local properties of
the galaxy.
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Ismael
Pérez Fournon