Manfred Stickel , D. Lemke , U. Klaas , L.V. Toth , et al. (on behalf of the ISOPHOT CISS Consortium MPIA, ESA, AIP, ICSTM, IPAC)
Max-Planck-Institut für Astronomie Koenigstuhl 17 D-69117 Heidelberg, Germany
The ISOPHOT Serendipity Survey utilized the otherwise unused slew time
between ISO's pointed observations with strip scanning measurements of
the sky in the far-infrared at 170 
.
During ISO's lifetime, more
than 12000 slew measurements totalling nearly 550 hours of observing
time were collected with ISOPHOT's 
pixel C200 array. The total
slew length exceeds 150000 degrees, leading to an incomplete sky
survey with a coverage of
.
The slews contain information about two fundamentally different types
of objects, namely unresolved extragalactic sources as well as
extended regions of galactic molecular clouds and cirrus
emission. Initial emphasis in the software development has been put on
the detection of point sources and the extraction of astrophysically
interesting parameters such as 170
fluxes from the crossed sources.
During the ISO mission, an initial study of detected point sources in
a 100 square degree high galactic latitude field near the North
Galactic Pole crossed by 
350 slews (``Minisurvey'') indicated that
detection completeness with respect to previously known IRAS sources
will be almost 100% for sources with 100 flux greater than 2 Jy. It
drops below
for 100
fluxes below 1.5 Jy with a detection
limit for the faintest sources of
at 170 .
At present the
bulk processing of the whole Serendipity database is underway. Since
the vast majority of the sources were found to be galaxies, it is
anticipated that a final Serendipity Survey catalogue will result in a
large catalogue of 2000 galaxies, where almost all have not been
previously observed at 170 .
Dedicated calibration observations have
been carried out during the ISO mission to tie the derived Serendipity
fluxes to an absolute photometric level. For most of the sources
lying closer than 1 arc-minute to the slews, a photometric accuracy
of
is expected.
The investigation of the galactic FIR emission has been started with a
search for cold spots in star forming regions and the analysis of the
170 to 100
flux ratio as a temperature indicator. Already known
compact CO sources in Chameleon and Ophiucus are used for calibration
purposes. First results from this study will be presented.