Galaxy formation and evolution

Abstract:

We predict the errors on counts-in-cells statistics measured in the future VIRMOS survey. Several effects are included, such as variation of clustering, biasing, and geometry. Most importantly for the survey strategy, sparse sampling appears to have no particular advantage in this case, especially for higher order statistics at high redshift. The predicted accuracy is a few percent for the variance, and about 10 percent for the skewness at z = 1 in a small dynamic range around 1 h(-1) Mpc.

Abstract:

We demonstrate the possibility of detecting mass concentrations (down to the level of 5 x 10(7) M.) in the center of galaxies with ground-based optical telescopes properly equipped, using Keplerian gaseous disks as probes. We predict that the high spatial resolution of HST equipped with STIS will allow to detect central mass concentrations down to the level of 5 x 10(6) M.. As a consequence, the detection of low mass concentrations in the range 10(6) - 10(7) M. will constitute a very appropriate use of HST.

Abstract:

Spectroscopy from the Infrared Space Observatory ISO has for the first time provided the sensitivity to exploit the diagnostic power of mid-infrared fine structure lines and PAH features for the study of ultraluminous infrared galaxies (L-IR > 10(12)L.). We report on observations obtained with SWS, ISOPHOT-S, and the CVF option of ISOCAM. From both fine structure lines and PAH features, we find that the majority of ULIRGs is predominantly powered by star formation. Our total sample of about 75 ULIRGs allows to search for trends within the class of ULIRGs: The fraction of AGNs increases with luminosity above similar to 3 x 10(12)L. but there is no obvious trend for ULIRGs to be more AGN-like with more advanced merger phase.