Tuesday, January 22, 2013
Astronomy Tea Talk
More than LESS: First results from the ALMA survey of the Extended Chandra Deep Field South
Alexander Karim, Durham University
Ever since their discovery submillimetre galaxies (SMGs) have been regarded as some of the most fascinating but also controversial objects in the early universe. Their potentially fundamental role in cosmic evolution - as prominent contributors to the global stellar mass growth - has been widely debated while a number of important aspects of their nature remained speculative. The lack of high-resolution imaging of large samples of SMGs at their discovery wavelength made multi-wavelength associations difficult, generally unreliable and often even impossible, with unpredictable consequences to the inferred number statistics and redshifts distribution of this galaxy population. Already in Cycle 0 ALMA's capabilities paved the way for a detailed 870um (band 7) continuum view of the flux-limited sample of 126 SMGs in the Extended Chandra Deep Field South. I will discuss how only 10 hours of ALMA integration time boost our understanding of SMGs with respect to their source number counts and counterpart association but also to reveal starbursts in the very early Universe. Furthermore, I will briefly summarize upcoming efforts in ALMA's Cycle 1 to investigate the SMG population, particularly its most distant constituents at redshifts of z>4. If time allows I will finally summarize the current status of the deep JVLA-COSMOS radio continuum survey -- covering 2 square degrees at 3GHz (10cm) and 0.6" resolution -- that will yield pioneering views of star formation and nuclear activity over a wide range in cosmic time.