TY - JOUR
T1 - Cosmic evolution of submillimeter galaxies and their contribution to stellar mass assembly
AU - Michałowski, M.
AU - Hjorth, J.
AU - Watson, D.
PY - 2010/5/1
Y1 - 2010/5/1
N2 - The nature of galaxies selected at submillimeter wavelengths (SMGs,
S850 ≳ 3 mJy), some of the bolometrically most luminous
objects at high redshifts, is still elusive. In particular their star
formation histories and source of emission are not accurately
constrained. In this paper we introduce a new approach to analyse the
SMG data. Namely, we present the first self-consistent UV-to-radio
spectral energy distribution fits of 76 SMGs with spectroscopic
redshifts using all photometric datapoints from ultraviolet to radio
simultaneously. We find that they are highly star-forming (median star
formation rate 713 M_&sun; yr-1 for SMGs at z > 0.5),
moderately dust-obscured (median A_V ~ 2 mag), hosting significant
stellar populations (median stellar mass 3.7 × 1011
M_&sun;) of which only a minor part has been formed in the ongoing
starburst episode. This implies that in the past, SMGs experienced
either another starburst episode or merger with several galaxies. The
properties of SMGs suggest that they are progenitors of present-day
elliptical galaxies. We find that these bright SMGs contribute
significantly to the cosmic star formation rate density (~20%) and
stellar mass density (~30-50%) at redshifts 2-4. Using number counts at
low fluxes we find that as much as 80% of the cosmic star formation at
these redshifts took place in SMGs brighter than 0.1 mJy. We find
evidence that a linear infrared-radio correlation holds for SMGs in an
unchanged form up to redshift of 3.6, though its normalization is offset
from the local relation by a factor of ~2.1 towards higher radio
luminosities. We present a compilation of photometry data of SMGs and
determinations of cosmic SFR and stellar mass densities.
Appendix is only available in electronic form at http://www.aanda.org
AB - The nature of galaxies selected at submillimeter wavelengths (SMGs,
S850 ≳ 3 mJy), some of the bolometrically most luminous
objects at high redshifts, is still elusive. In particular their star
formation histories and source of emission are not accurately
constrained. In this paper we introduce a new approach to analyse the
SMG data. Namely, we present the first self-consistent UV-to-radio
spectral energy distribution fits of 76 SMGs with spectroscopic
redshifts using all photometric datapoints from ultraviolet to radio
simultaneously. We find that they are highly star-forming (median star
formation rate 713 M_&sun; yr-1 for SMGs at z > 0.5),
moderately dust-obscured (median A_V ~ 2 mag), hosting significant
stellar populations (median stellar mass 3.7 × 1011
M_&sun;) of which only a minor part has been formed in the ongoing
starburst episode. This implies that in the past, SMGs experienced
either another starburst episode or merger with several galaxies. The
properties of SMGs suggest that they are progenitors of present-day
elliptical galaxies. We find that these bright SMGs contribute
significantly to the cosmic star formation rate density (~20%) and
stellar mass density (~30-50%) at redshifts 2-4. Using number counts at
low fluxes we find that as much as 80% of the cosmic star formation at
these redshifts took place in SMGs brighter than 0.1 mJy. We find
evidence that a linear infrared-radio correlation holds for SMGs in an
unchanged form up to redshift of 3.6, though its normalization is offset
from the local relation by a factor of ~2.1 towards higher radio
luminosities. We present a compilation of photometry data of SMGs and
determinations of cosmic SFR and stellar mass densities.
Appendix is only available in electronic form at http://www.aanda.org
UR - http://www.scopus.com/inward/record.url?scp=77952918012&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/200913634
DO - 10.1051/0004-6361/200913634
M3 - Article
SN - 0004-6361
VL - 514
SP - 67
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
ER -