Andrew Bunker

Abstract:

The study of the physical properties of high-redshift galaxies has become one of the major goals of extragalactic astronomy. In particular the massassembly histories of galaxies have been the focus of many studies at redshifts 1 to 3. In the purpose of probing the dynamics of intermediate and high-redshift galaxies, we have designed a research program to carry out a near-infrared spectroscopic follow up of spatially resolved distant galaxies. Here, we present the results for A370-A5 (z=1.341), an arc behind the lens cluster Abell 370 (z=0.374), observed in the case of science verification programme of SINFONI/VLT. The natural magni fication due to massive galaxy clusters allows to spatially resolve and constrain the dynamics of young star forming galaxies 1 to 3 magnitudes fainter than those selected in blank fields. Thus, the study of lensed galaxies allows to probe a low mass regime of galaxies not accessible in standard observation. In this particular case, we found that the gas distribution and kinematics are consistent with a bipolar outflow with a range of velocities of v ∼ 100km/s. © 2007 Springer-Verlag Berlin Heidelberg.

Abstract:

We present results from a Keck optical and near IR spectroscopic study of the giant emission line halos of the z>3 High Redshift Radio Galaxies (HiZRGs) 4C 41.17, 4C 60.07 and B2 0902+34. The outer regions of these halos show quiet kinematics with typical velocity dispersions of a few hundred km∈s-1 and velocity shears consistent with rotation. The inner regions contain shocked, clumpy cocoons of gas closely associated with the radio lobes with disturbed kinematics and expansion velocities and/or velocity dispersions >1000 km∈s-1. We also find evidence for the ejection of chemically enriched material in 4C 41.17 up to a distance of 60 kpc along the radio-axis. We infer that these HiZRGs are undergoing a final jet-induced phase of star formation with the ejection of most of their interstellar medium before evolving to become "red and dead" Elliptical galaxies. © 2007 Springer Science+Business Media B.V.