Bibcode
Wuyts, S.; Wang, L.; Valtchanov, I.; Tacconi, L. J.; Sturm, E.; Scott, D.; Sanchez-Portal, M.; Roseboom, I.; Rosario, D.; Rodighiero, G.; Riguccini, L.; Pozzi, F.; Popesso, P.; Poglitsch, A.; Pérez-García, A. M.; Page, M.; Oliver, S. J.; Nordon, R.; Maiolino, R.; Magdis, G.; Le Floc'h, E.; Ivison, R. J.; Genzel, R.; Förster Schreiber, N. M.; Elbaz, D.; Daddi, E.; Conley, A.; Cimatti, A.; Cepa, J.; Bongiovanni, A.; Bock, J.; Béthermin, M.; Aussel, H.; Andreani, P.; Altieri, B.; Symeonidis, M.; Santini, P.; Berta, S.; Saintonge, A.; Lutz, D.; Magnelli, B.
Bibliographical reference
Astronomy and Astrophysics, Volume 561, id.A86, 22 pp.
Advertised on:
1
2014
Journal
Citations
217
Refereed citations
206
Description
We study the evolution of the dust temperature of galaxies in the SFR-
M∗ plane up to z ~ 2 using far-infrared and
submillimetre observations from the Herschel Space Observatory taken as
part of the PACS Evolutionary Probe (PEP) and Herschel Multi-tiered
Extragalactic Survey (HerMES) guaranteed time key programmes. Starting
from a sample of galaxies with reliable star-formation rates (SFRs),
stellar masses (M∗) and redshift estimates, we grid
the SFR- M∗parameter space in several redshift ranges
and estimate the mean dust temperature (Tdust) of each
SFR-M∗ - z bin. Dust temperatures are inferred using
the stacked far-infrared flux densities (100-500 μm) of our
SFR-M∗ - z bins. At all redshifts, the dust
temperature of galaxies smoothly increases with rest-frame infrared
luminosities (LIR), specific SFRs (SSFR; i.e.,
SFR/M∗), and distances with respect to the main
sequence (MS) of the SFR- M∗ plane (i.e., Δlog
(SSFR)MS = log
[SSFR(galaxy)/SSFRMS(M∗,z)]). The
Tdust - SSFR and Tdust - Δlog
(SSFR)MS correlations are statistically much more significant
than the Tdust - LIR one. While the slopes of
these three correlations are redshift-independent, their normalisations
evolve smoothly from z = 0 and z ~ 2. We convert these results into a
recipe to derive Tdust from SFR, M∗ and z,
valid out to z ~ 2 and for the stellar mass and SFR range covered by our
stacking analysis. The existence of a strong Tdust -
Δlog (SSFR)MS correlation provides us with several
pieces of information on the dust and gas content of galaxies. Firstly,
the slope of the Tdust - Δlog (SSFR)MS
correlation can be explained by the increase in the star-formation
efficiency (SFE; SFR/Mgas) with Δlog
(SSFR)MS as found locally by molecular gas studies. Secondly,
at fixed Δlog (SSFR)MS, the constant dust temperature
observed in galaxies probing wide ranges in SFR and M∗
can be explained by an increase or decrease in the number of
star-forming regions with comparable SFE enclosed in them. And thirdly,
at high redshift, the normalisation towards hotter dust temperature of
the Tdust - Δlog (SSFR)MS correlation can be
explained by the decrease in the metallicities of galaxies or by the
increase in the SFE of MS galaxies. All these results support the
hypothesis that the conditions prevailing in the star-forming regions of
MS and far-above-MS galaxies are different. MS galaxies have
star-forming regions with low SFEs and thus cold dust, while galaxies
situated far above the MS seem to be in a starbursting phase
characterised by star-forming regions with high SFEs and thus hot dust.
Herschel is an ESA space observatory with science instruments provided
by European-led Principal Investigator consortia and with important
participation from NASA.Appendices are available in electronic form at
http://www.aanda.org
Related projects
Evolution of Galaxies
Galaxy evolution is a crucial topic in modern extragalactic astrophysics, linking cosmology to the Local Universe. Their study requires collecting statistically significant samples of galaxies of different luminosities at different distances. It implies the ability to observe faint objects using different techniques, and at different wavelengths
Jorge
Cepa Nogue