The Herschel ATLAS is an Open Time Key Project to be
carried out by an international collaboration of institutions that
will use the Herschel Space Observatory to survey a
large area of sky in 5 photometric infrared/submm bands. It will be the first
wide-field blind survey in this crucial wavelength range.
The flagship science project is the
survey of the dust and dust-obscured star formation in ~105 galaxies
in the nearby (z<0.3) universe. However, there are many other science goals: to
determine the nature of the highly-confused Planck sources
in the ATLAS fields,
to estimate the relative contributions of star-forming galaxies and the
Sunyaev-Zeldovich effect in high-redshift clusters, to investigate the
evolution of the mass
profiles of galaxies, the relation between the formation of stars and
black-holes in quasars, the large-scale structure of the universe on 100-1000
Mpc scales, and to carry out the first census of prestellar cores and
protostars at high galactic latitude.
UCLan will be involved in the
Local Universe Program
of the Herschel ATLAS, in particular in the analysis of the far-IR/submm
properties of elliptical galaxies and
in the analysis of the data overlapping
with the optical/near-IR GAMA survey (of which we
are also a co-investigator institute).
The main objective of the analysis of Herschel ATLAS data of
elliptical galaxies will be to characterise their
(temperatures and masses) by combining Herschel data with data
from radio to infrared wavebands and fitting their spectral energy
distributions. This will give a census of the dust
properties of these
galaxies in the local universe. The presence of cool dust in some ellipticals
given the sputtering effects expected from hot X-ray emitting gas in them.
Dust lifetimes are expected to be short in those hostile environments.
The presence of dust will be correlated with other galaxy properties to
find out which types of ellipticals harbour cool dust and whether its presence
could be a relic from relatively recent merger events, or if it is a more
ubiquitous and long-lived property of ellipticals.
The main objective of the analysis of Herschel ATLAS data
of GAMA galaxies will be to
derive the infrared (IR) luminosity function (LF)
of gas-rich local Universe galaxies. The
measurements will be compared with theoretical prediction as to how the
function depend on the macroscopic quantities such as mass and
morphology. Crucially, this would provide a local Universe reference
measurement to quantify the effects of downsizing
over cosmic time - that is
to understand the extent to which SF activity becomes incresingly limited to
systems of lower mass as redshift decreases. Finally, the precise measurement
of the IR LF will yield a better estimate of the local IR
and thus of the contribution of local Universe galaxies to the IR background.
Another objective is to apply our panchromatic SED modelling tool to
the combined optical/NIR and far-IR/submm data from GAMA and
Herschel-ATLAS observations of gas rich galaxies to derive for the first
time intrinsic physical
parameters like dust opacities, star-formation
rates (SFRs) and star-formation histories on an object by object base.