2. Dust & Gas in High-z QSOs - PhD Thesis

Dust & Gas in High-z QSOs - PhD Thesis

Beelen, A.

This thesis presents the study of dust and gas in high redshift quasars (QSOs) based on (sub)millimeter and radio observations. The surveys of the infrared and radio continuum of optically luminous and radio-quiet QSOs at \(1.9 < z < 6.4\) indicate the presence of large dust masses, including in the \(z > 6\) QSOs. The relationship between infrared and radio emission sfolowed by local galaxies is also found for the high-z QSOs, suggesting that the dust heating is dominated by young massive stars. These studies have allowed us to derive a relationship between the black hole and star formation activity. The high star formation rates (\(\approx 1000\ \mathrm{M_\odot/yr}\)) point to intense starbursts which have to be sustained by massive reservoirs of molecular gas. The detection of CO in J1409+5628 at z=2.56 in described in detail and a global study of the CO emission in high-z sources is presented. In a few cases, the detection of several CO transitions enables to constrain the physical conditions, indicating gas temperatures of 60-100 K, and densities of \(10^{3-4}\ \mathrm{cm^{-3}}\), comparable to what is found in M82 and Arp220. Finally, the detection of CI and HCN is reported in two high-z QSOs. | These studies have allowed us to constrain the physical conditions in the host galaxies of high-z QSOs, among the most massive objects in the universe. These exploratory studies, which open the way to the study of the interstellar medium in the extreme environments of the first galaxies, will come to full maturity when the satellite Herschel and the interferometers eVLA and ALMA will be operational.

You can find my thesis on line on multidisciplinary theses server under the reference tel-00011634. You can find the abstract on ADS under the reference 2004PhDT........43B.