Publication Date:
2019-07-12
Description:
We present a catalog of 191 extragalactic sources detected by the Atacama Cosmology Telescope
(ACT) at 148 GHz and/or 218GHz in the 2008 Southern survey. Flux densities span
14-1700mJy, and we use source spectral indices derived using ACT-only data to divide our
sources into two sub-populations: 167 radio galaxies powered by central active galactic nuclei
(AGN), and 24 dusty star-forming galaxies (DSFGs). We cross-identify 97% of our sources
(166 of the AGN and 19 of the DSFGs) with those in currently available catalogs. When
combined with flux densities from the Australian Telescope 20 GHz survey and follow-up
observations with the Australia Telescope Compact Array, the synchrotron-dominated population
is seen to exhibit a steepening of the slope of the spectral energy distribution from 20
to 148GHz, with the trend continuing to 218GHz. The ACT dust-dominated source population
has a median spectral index, alpha(sub 148218), of 3.7+0.62 or
0.86, and includes both local galaxies and
sources with redshifts as great as 5.6. Dusty sources with no counterpart in existing catalogs
likely belong to a recently discovered subpopulation of DSFGs lensed by foreground galaxies
or galaxy groups.
Keywords:
Astronomy; Astrophysics
Type:
GSFC-E-DAA-TN9888
Format:
application/pdf
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