Atacama Cosmology Telescope: Dusty Star-forming Galaxies and Active Galactic Nuclei in the Equatorial Survey

Abstract

We present a catalog of 510 radio-loud active galactic nuclei (AGN, primarily blazars) and 287 dusty star-forming galaxies (DSFGs) detected by the Atacama Cosmology Telescope at > 5σ significance in frequency bands centered on 148 GHz (2 mm), 218 GHz (1.4 mm) and 277 GHz (1.1 mm), from a 480 sqdeg strip centered at R.A. 00 h on the celestial equator with additional 360 sq-deg shallower auxiliary fields at other longitudes. The combination of the deepest available 218 GHz wide-field imaging, our 277 GHz data, and multiband filtering results in the most sensitive wide-field millimeter-wave DSFG selection to date with rms noise level referenced to 218 GHz reaching below 2 mJy. We have developed new techniques to remove Galactic contamination (including evidence for CO(2-1) line emission) from the extragalactic catalog, yielding a catalog of 321 Galactic sources in addition to the extragalactic catalog. We employ a new flux debiasing method that accounts for the heterogeneous sample selection in the presence of Galactic cuts. We present the spectral properties and source counts of the AGN and DSFGs. The DSFG spectra depart from the Rayleigh-Jeans regime of an optically thin modified blackbody between 218 GHz and 277 GHz, consistent with optically thick emission. For AGN with 148 and 218 GHz flux density > 50 mJy, we estimate the inter-year RMS fractional deviation in flux density due to source variability to be 40% with a 0.98 inter-band correlation coefficient. We provide source counts for AGN in the range 8-2870 mJy and for DSFGs in the range 8-90 mJy. Our DSFG arXiv:1905.04592v1 [astro-ph.GA] 11 May 2019 counts probe both the brighter, lensed population and the fainter, unlensed population. At 277 GHz we report the first measurements of source counts at these flux densities, finding an excess above most model count predictions. Finally, we present thirty of the brightest DSFGs that were selected for multi-frequency study as candidate high-z lensed systems.

Millimeter-wave Point Sources from the 2500 Square Degree SPT-SZ Survey: Catalog and Population Statistics

“…The current work features a roughly 50% reduction in the error bars on our measured number counts, consistent with the increase in sky area utilized. We find our measured number counts are also consistent with all-sky results from Planck (Planck Collaboration et al 2013 and recently released results from ACT (Gralla et al 2020).…”

“…Figure 17. Upper: total source counts (with no cuts applied other than removing sources identified as stars) for the current work, compared with total source counts from Planck (Planck Collaboration et al 2013) and the ACT (Gralla et al 2020). Lower: synchrotron-dominated counts for the current work (shown with no cuts applied other than removing stars), compared with the Planck Multi-frequency Catalog of Non-thermal Sources (Planck Collaboration et al 2018), where the counts were calculated applying the 70% Galactic mask, GAL070, and ACT AGN counts from Gralla et al (2020).…”

“…The upper panels of Figure 17 provide a comparison between the total counts from SPT-SZ from the current work (with only stars removed) with number counts from the allsky survey from Planck at 100, 143, and 217 GHz (Planck Collaboration et al 2013), and number counts from the Atacama Cosmology Telescope (ACT; Gralla et al 2020). The total counts from ACT presented here have been drawn from the sum of synchrotron-and dust-dominated subpopulations, as presented in Table 5 of Gralla et al (2020). The lower panels of Figure 17 compare synchrotron-dominated counts from SPT-SZ (similarly shown with only stars removed) compared with number counts from the Planck Multi-frequency Catalog of Non-thermal Sources(Planck Collaboration et al 2018), excluding Galactic-plane sources using the GAL070 mask, and counts for AGN sources from ACT (Gralla et al 2020).…”

“…The total counts from ACT presented here have been drawn from the sum of synchrotron-and dust-dominated subpopulations, as presented in Table 5 of Gralla et al (2020). The lower panels of Figure 17 compare synchrotron-dominated counts from SPT-SZ (similarly shown with only stars removed) compared with number counts from the Planck Multi-frequency Catalog of Non-thermal Sources(Planck Collaboration et al 2018), excluding Galactic-plane sources using the GAL070 mask, and counts for AGN sources from ACT (Gralla et al 2020). The total and synchrotron-dominated number counts from SPT-SZ are broadly consistent with both Planck and ACT across the full range of fluxes overlapping between the different surveys.…”

“…The advent of large-area and multiband surveys allowed detections probing the brightest and rarest SMGs. This included surveys conducted using the SPT at 1.4, 2.0, and 3.2 mm (e.g., V10), the Spectral and Photometric Imaging Receiver (SPIRE) at 250, 350, and 500 μm on the Herschel Space Observatory (e.g., Eales et al 2010), the Planck satellite(e.g., Planck Collaboration et al 2016a), and the Atacama Cosmology Telescope(e.g., Gralla et al 2020).…”