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NRAO/Socorro Colloquium Series

Marusa Bradac

University of California, Davis

Breaking Cosmic Dawn: Studying z~7 Galaxies with Cluster Lenses as Cosmic Telescopes

In the recent years HST enabled us to detect galaxies as far as z~11. They are likely beacons of the epoch of reionization, which marked the end of the so-called ``Dark Ages'' and signified the transformation of the universe from opaque to transparent. However very little is known about those galaxies, and a confirmation of their redshift is still out of our hands. Clusters of galaxies, when used as cosmic telescopes, can greatly simplify the task of studying and finding these and lower-z galaxies. With a massive cluster one can gain several magnitudes of magnification over a typical observing field, enabling imaging and spectroscopic studies of intrinsically lower-luminosity galaxies than would otherwise be observable, even with the largest telescopes. Several large surveys (SURFS UP for Spitzer imaging, GLASS for HST spectrscopy, and Frontier Field innitiative for ultra deep HST imaging) have been started recently with the main goal of identifying and studying star formation of these sources. Still, beyond z~7, galaxies remain enshrouded in mystery, at least from a spectroscopic point of view. To advance our understanding of the epoch of reionization, we need to spectroscopically measure the redshifts and the available fuel for star formation. I will describe why ALMA is a unique telescope that can perform this task.



October 11, 2013
11:00 am

Array Operations Center Auditorium

All NRAO employees are invited to attend via video, available in Charlottesville Room 230, Green Bank Room 137 and Tucson N525.

Local Host: Chris Carilli

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