12th of September 2015 |
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ASKAP discovery of HI gas in a young radio galaxy |
by James Allison (CASS) |
The ASKAP Boolardy Engineering Test Array
(BETA) is being used to search for atomic hydrogen (HI) absorption at
redshifts between 0.4 and 1, spanning almost 3.5 billion years of cosmic
history. In their recent paper, Allison et al. (2015) demonstrated the unique capability of
ASKAP for performing future wide-field HI absorption surveys in a largely
unexplored epoch. Their first discovery revealed the cool gas surrounding
the young radio galaxy PKS B1740-517, also providing the first spectroscopic
redshift for this source. The spectrum shown was constructed by averaging
over several observations with BETA and has an RMS sensitivity of 0.15 per
cent of the continuum emission. ASKAP photo credit: Robert Hollow |