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.
Instrument
PHT03 , PHT22 , PHT37 , PHT39
Temporal Coverage
1996-04-11T06:54:15Z/1997-11-15T22:12:14Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, Richter et al., 1999, 'ISOPHOT Observations of an Unbiased Sample of Blue Compact Galaxies ', 1.0, European Space Agency, https://doi.org/10.5270/esa-oayx12q
