CfA Colloquium Schedule Fall 2009
 10 September 2009

10 September 2009

Speaker: Chris Carilli (NRAO)

Title:Radio observations of galaxy formation

Abstract:Remarkable progress has been made in the study of galaxy formation over the last decade, primarily through optical and near-IR observations. The cosmic history of star formation, and the build-up of stellar mass, has been well quantified as a function of galaxy mass and environment, through its peak during the 'epoch of galaxy assembly' (z ~ 2), back to the near-edge of cosmic reionization and first light (z > 6). While progress has been impressive, optical studies of galaxy formation are limited to the stars and ionized gas, and are plagued by uncertainties in obscuration. Studies at centimeter through submillimeter wavelengths are required to probe deep into the earliest, most active, and dust obscured, phases of galaxy formation, revealing the star formation, dust, and cool molecular and atomic gas. I will present radio and (sub)mm observations of forming galaxies at two key epochs in the early Universe. I will start with massive galaxy formation at the end of cosmic reionization, through the study of the host galaxies of the most distant quasars (z ~ 6). These galaxies are under-going 'maximal starbursts', with star formation rates > 1000 Mo/year, and molecular gas masses > 1e10 Mo. Through gas dynamics we estimate the ratio of the bulge mass to black hole mass. These observations imply that we are witnessing the co-eval formation of large elliptical galaxies, and super-massive black holes, within 1 Gyr of the Big Bang. I will then present observations of normal galaxy formation during the epoch of galaxy assembly. We observe rapid secular galaxy evolution over a broad range in mass scale, and we find that the dominant baryon component is molecular gas (ie. gas mass/stellar mass > 1). I will conclude with a summary of the remarkable potential of ALMA and the EVLA to determine the cool gas density history of the Universe.

Video of the Presentation (Talks can be viewed with RealPlayer. Free download is available from )


Section Photo