The following document lists the file abstract/GRICHTER_BCGALAXY.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
SCIENTIFIC ABSTRACT
Blue Compact Galaxies are explained as star formation bursts in old unevolved
galaxies of primordial gas clouds. They are therefore of considerable
interest for the formation and evolution of galaxies. Many of the open
problems in the present knowledge of their nature are connected with
phenomena which manifest themselves in the IR range. Whereas some individual
BCGs are observed extensively, there is a lack of systematic observations of
well defined statistical samples. We propose IR broadband photometry in 4
bands (11.5, 25, 60, 100 um) of an unbiased sample of BDGs which have
been selected from an objective prism survey by well defined criteria
(high excitation HII region characteristics) and for which complete data on
element abundances, radial velocities and UBVR photometry are already
available. Supplementary optical CCD, near-infrared (JHK) and radio
observations are planned.
Many of the objects in our list have not been detected by IRAS, and
very few of them in only one band (60um).
OBSERVATION SUMMARY
The spectral energy distributions of the BCGs in our list will be
measured in the four IRAS bands with PHT-P (11.5, 25 um) and PHT-C
(60, 100 um).
All objects are rather compact with sizes smaller than 20" so that one
telescope pointing is sufficient to measure the total flux. For PHT-P we
choose the 52" aperture in order to be independent of the telescope
pointing accuracy. For accurate determination of the celestial background
chopped measurements with two reference positions (triangular chopping)
will be performed. For
all measurements a chopper throw of 150 arcsec will be used in order to
obtain the reference fluxes for background subtraction at the same
positions for all filters.
The objects will be observed with the multi-filter AOTs PHT03 (11 and 25 um),
and PHT22 (60 and 100 um),
except 0335-052 where mapping with PHT32 is required due to the vicinity
to a bright point source and cirrus emission. For this object a map
with 4 X 5 positions will be performed at 60 and 100mu.
The on-source integration times at 60 and 100 um are 32 sec for all objects
except for the one to be mapped with PHT32, where the total integration
time is 520 sec for each filter. At 11.5 and 25 um the brighter objects
which have been detected by IRAS at 60 um will be observed 64 sec in each
filter.
For the fainter objects not detected by IRAS the integration time will be
32 sec at
11.5 um and 128 sec at 25 um, respectively (Note that the observations
with the P1 detector are performed during heating of the P2. The integration of
32 sec with the P1 detector completely falls into the heating time of 90 sec
required for the P2 detector. Thus the total spacecraft time does not change
if the P1 observations are performed or not.).
The majority ot the sample is located in the strip
RA = 9h - 16h and delta = 49deg - 61deg.