Recent results from the Herschel-ATLAS – Seminar by Matt Jarvis

This week, Matt Jarvis (from the University of the Western Cape and the University of Hertfordshire) brought us up to speed on the latest results from Herschel, the infrared space telescope launched by ESA in 2009. Matt reminded us of the amount of information that can be gained from the mission because about half the light emitted by stars is absorbed and re-emitted by dust in the infrared.

Matt spoke specifically about ATLAS, which is a wide area extragalactic survey using Herschel. Although the survey is not yet complete, the data collected so far has yielded some interesting science. For example, Dunne et al. have shown that the dust mass function evolves over time, where galaxies at higher redshift have much higher dust masses. Coppin et al. found an excess of far-infrared sources in the centres of galaxy clusters, which could affect the Sunyaev-Zel’dovich signal in telescopes such as ACT and SPT.

Selection of gravitational lenses at submillimetre wavelengths. Strongly lensed SMGs (submillimetre galaxies) dominate at very bright fluxes. Negrello et al. (2011).

Strongly lensed galaxies have been detected in the Science Demonstration Phase (SDP)
and Negrello et al. have shown that Herschel is primed to detect many more strongly lensed, high redshift galaxies, which are powerful probes of galaxy evolution and cosmology. Matt also spoke about the far-infrared–radio correlation, showing that even outside the local universe, radio seems to trace star formation just as well as the far-infrared.

The Herschel-ATLAS survey looks set to yield many interesting results as the data is analysed. There are many opportunities for collaboration, since SALT is one of the primary spectroscopic telescopes used in the survey and MeerKAT will be an excellent instrument for cross-matching of far-infrared sources.

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