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This week's colloquium: Cosmology in the radio: from LOFAR to the SKA

Submitter: Mario Santos (CENTRA, Istituto Superior Tecnico, Lisbon)
Description: (NB: Note the unusual start-time: 16:00!)

A new generation of radio telescopes with unprecedented capabilities for astronomy and fundamental physics will be in operation over the next few years. I will address some of the possibilities for Cosmology offered by these instruments, taking advantage of their large survey speed and bandwidths, such as LOFAR, Apertif, ASKAP and the future SKA Phase 1 and 2. In particular, I will discuss observations of the high redshift Universe at low frequencies to probe the Epoch of Reionization and large galaxy surveys that will allow to probe the Universe at low redshifts (z~1) to set stringent constraints on the nature of dark energy, modified gravity and primordial non-Gaussianity. Finally, I will discuss the use of HI intensity mapping techniques to sample the large scale structure of the Universe at low z.

Image caption: The background picture shows a large scale simulation (1 Gpc) of the Epoch of Reionization at redshift ~ 8 when the Universe was about 50% ionised. This was done using a "fast and large" simulation software (see simfast21.org and http://arxiv.org/abs/0911.2219). LOFAR should be able probe this at the statistical level while SKA should be able to actually image this epoch. The foreground bottom right figure shows the expected constraints on dark energy using radio galaxy surveys such as EMU (ASKAP) and WODAN (Apertif) and cross-correlations with a shallow optical survey (see http://arxiv.org/abs/1205.1048).

Copyright: Mario Santos
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