ACT Data Products - 148/218 GHz Point Source Catalog
This table contains a catalog of 191 extragalactic sources detected by the Atacama Cosmology Telescope (ACT) at 148 and/or 218 GHz in the 2008 Southern survey. Flux densities span 14 -1700 mJy, and the authors use source spectral indices derived using ACT-only data to divide their sources into two subpopulations: 167 radio galaxies powered by central active galactic nuclei (AGN) and 24 dusty star-forming galaxies (DSFGs). They cross-identify 97% of their sources (166 of the AGN and 19 of the DSFGs) with those in currently available catalogs. When combined with flux densities from the Australia 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 148 GHz, with the trend continuing to 218 GHz. The ACT dust-dominated source population has a median spectral index, alpha_148-218GHz , of 3.7^+0.62 _-0.86 , and includes both local galaxies and sources with redshifts up to z=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.
The ACT experiment (Swetz et al., 2011, ApJS, 194, 41) is situated on the slopes of Cerro Toco in the Atacama Desert of Chile at an elevation of 5190m. ACT's latitude gives access to both the northern and southern celestial hemispheres. Observations occurred simultaneously in three frequency bands, at 148 GHz (2.0 mm), 218 GHz (1.4 mm) and 277 GHz (1.1 mm) with angular resolutions of roughly 1.4, 1.0 and 0.9 arcminutes, respectively.
The ACT-detected source list contains 169 sources selected at 148 GHz with S/N > 5, spanning two decades in flux density, from 14 to 1700 mJy. The 218 GHz map independently yielded 133 sources with S/N > 5. The combination of these two independent source lists from which the present table was constructed gives a total count of 191 sources, with 110 galaxies detected with S/N > 5 at both frequencies.
Sync = synchrotron-dominated sources (the vast majority of which are cross-identified with radio catalogs)
Dust = low-redshift dust-dominated sources with IRAS counterparts (typically ULIRGs) and dust-dominated sources also observed by the South Pole Telescope (SPT), or with no cross-identification, either shown or assumed to be high-redshift star-forming galaxies.
Byte-by-byte Description of file: table4.dat
Note (1): Notes as follows:
d = An ACT source not cross-identified with the catalogues specified in Section 5 * = Name from 2010 November follow-up observation catalogue
Note (2): Classification codes are:
Sync = synchrotron-dominated sources (the vast majority of which are cross-identified with radio catalogues) Dust = low-redshift dust-dominated sources with IRAS counterparts (typically ULIRGs) and dust-dominated sources also observed by the South Pole Telescope (SPT), or with no cross-identification, either shown or assumed to be high-redshift star-forming galaxies.
148 GHz Point Source Catalog
This is a catalog of 157 point sources detected in a 148 GHz data collected by ACT during its 2008 observing season. The sources listed in the catalog were detected as >5.25 sigma peaks in a 455 square-degree subset of the ACT map that had been weighted by the square root of the number of observations and optimally filtered for point source detection. All but three sources have counterparts at other frequencies (ACT-S J034157—515140, ACT-S J004042—511830, and ACT-S J035343—534553). These three sources may be spurious detections. The raw flux density is provided for all sources (column 5). For sources with raw flux density less than 50 mJy, deboosted flux densities (column 6) with errors (columns 7 and 8) are also provided and recommended for external use. The deboosted flux density accounts for the fact that, for a source population for which the counts are a steeply falling function of flux, a source's measured flux density in the presence of noise (i.e., the raw flux density) is likely to be an over-estimate of its intrinsic value.
Col 1 : IAU Name