| Description |
Despite IRAS, ISO and Spitzer, there is still much we do know about
dust in galaxies, partly because of sensitivity limitations and partly
because previous telescopes were insensitive to dust colder than about
15 K. Our knowledge is especially poor for ellipticals which have barely
been detected by previous telescopes. As part of the SPIRE GT programme,
we propose to obtain images at 250, 350 and 520 microns of a sample of
323 galaxies selected to be useful both for studying the dust in individual
galaxies and for drawing statistical conclusions about the role of dust in
galaxies in general. The Herschel Reference Survey will be the first survey
sensitive to all the dust in galaxies and which will detect dust in galaxies of all
Hubble types. Apart from its legacy value, we intend to use the survey for
the following projects: 1) We will make a comprehensive study of dust
along the Hubble sequence, investigating how the dust mass varies with
Hubble type. mass of stars, current star formation rate, past star formation
rate, and the masses of molecular and atomic gas. 2) We will investigate
within individual galaxies the connections between the star formation
rate and the different phases of the ISM, from the nucleus to the HI outside
the optical disk. 3) We will investigate how the mass and distribution of
dust depend on a galaxys environment. 4) We will investigate whether
there is an intergalactic dust cycle by looking for dusty halos, dusty
superwinds and tidally-stripped dust around galaxies. 5) We will
investigate the origin of dust in ellipticals, and the evolution
of the galaxies themselves, by looking for dust disks and dust shells
and by looking for correlations between the mass and distribution
of the dust and the other properties of the galaxy. 6) We will measure
the local luminosity and dust-mass functions, which will be necessary to
interpret the results of the deep surveys, another part of the
proposed GT programme. The total time required for the survey is
112.6 hours. |
