we propose to use phot to carry out measurements at wavelengths of 11.5, 60 and 160um (11.5, 60, 135 and 200 for the brightest objects) of a complete sub-sample of optically selected bright quasars taken from two recently completed multicolour (u,b,v,r,i) quasar surveys. the optical fluxes are in the range 15 < b < 17, partially overlapping those of the pg survey, but with a much better photometric accuracy (sigma_b virgul 0.1mag). our samples show that the true surface density of quasars in the range 15<b<16.5 is significantly higher (a factor 3) with respect to the pg survey. no other complete quasar surveys sample such bright fluxes. rosat and vla observations have been obtained or are going to be obtained for the whole bright sub-sample. this programme aims at comparing the space density of optically-selected quasars in the far-infrared (fir) with our new estimation of the blue band space density of these objects. this comparison will be done by means of the first ever calculation of the bivariate luminosity function. this will tell us how the optical-infra-red relation for quasars changes as a function of both luminosity and redshift. using this relation we can derive the relative strengths of the different components responsible for infra-red emission and disentangle the dependences on redshift and luminosity. note that this project cannot be carried out by using iras data because of the low sensitivity of this survey and the lack of any complete quasar sample observed by this satellite. moreover, photometry at different fir frequencies will measure the spectral energy density distribution (s.e.d.) of the population and address the issues of the spectral turnover and the relative importance of thermal and non-thermal emission in the far-infrared. 30 sources will be observed in case of spring launch and the total observing time required is virgul 15 hours, all 49 sources can be observ...ed in case of autumn launch with a total observing time of virgul 20 hours.
Instrument
PHT03 , PHT22
Temporal Coverage
1996-07-20T03:45:39Z/1997-05-05T18:47:09Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's 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, 1999, Fir Photometry Of A Complete Sample Of Optically Selected Bright Quasars., 1.0, European Space Agency, https://doi.org/10.5270/esa-p9xqjan
