Cosmic star formation history associated with QSO activity: an approach using the black hole to bulge mass correlation

The tight correlation between the masses of central black holes and their host spheroids in nearby galaxies and active galactic nuclei (AGN) suggests that black hole growth is closely related to their spheroid formation. Based on our previous work regarding such a joint evolutionary scheme and the consequential black hole to bulge mass correlation, we use the X-ray luminosity function of AGN and the cosmological evolution rate which are from ROSAT X-ray surveys to estimate the cosmic star formation history associated with the black hole growth. By the basic assumption that the major black hole growth occurs during the luminous AGN phase, the luminosity function of AGNs as a function of redshift traces not only the accretion history of the black holes but also the cosmic star formation history of the spheroids. Although the space density of the especially luminous QSOs is very low, we show that the total amount of star formation associated with the massive black hole growth is almost the same as that of Lyman Break Galaxies detected by the current optical deep surveys. We thus argue that the optical deep surveys may miss about half of the net star formation in our Universe. This is probably due to in part significant dust extinction as well as the small field of view of previous optical surveys which cannot sample such rare events with relatively short time scale. However, the far infrared emission from the dust heated by star formation on-going during the black hole growth could sufficiently account for the observed SCUBA number counts, and would be the probable dominating energy source of the SCUBA population. Subject headings: galaxies: elliptical and lenticular, cD–galaxies: active–galaxies: evolution–quasars: general–(ISM:) dust, extinction