Abstract Active galactic nuclei (AGNs) are powered by geometrically thin accretion disks surrounding a central supermassive black hole. Here we explore the evolution of stars embedded in these extreme astrophysical environments (AGN stars). Because AGN much hotter and denser than most components interstellar medium, subject to very different boundary conditions normal stars. They also strongly ...

We measure the build-up of the stellar mass of galaxies from z = 6 to z = 1. Using 15 band multicolor imaging data in the NICMOS Ultra Deep Field we derive photometric redshifts and masses for 796 galaxies down to HAB = 26.5. The derived evolution of the global stellar mass density of galaxies is consistent with previous star formation rate density measurements over the observed range of redshi...