A Submillimeter Perspective on the GOODS Fields (SUPER GOODS). III. A Large Sample of ALMA Sources in the GOODS-S

Abstract

We analyze the > 4σ sources in the most sensitive 100 arcmin 2 area (rms < 0.56 mJy) of a SCUBA-2 850 µm survey of the GOODS-S and present the 75 band 7 ALMA sources (> 4.5σ) obtained from high-resolution interferometric follow-up observations. The SCUBA-2-and hence ALMA-samples should be complete to 2.25 mJy. Of the 53 SCUBA-2 sources in this complete sample, only five have no ALMA detections, while 13% (68% confidence range 7-19%) have multiple ALMA counterparts. Colorbased high-redshift dusty galaxy selection techniques find at most 55% of the total ALMA sample. In addition to using literature spectroscopic and optical/NIR photometric redshifts, we estimate FIR photometric redshifts based on an Arp 220 template. We identify seven z 4 candidates. We see the expected decline with redshift of the 4.5 µm and 24 µm to 850 µm flux ratios, confirming these as good diagnostics of z 4 candidates. We visually classify 52 ALMA sources, finding 44% (68% confidence range 35-53%) to be apparent mergers. We calculate rest-frame 2 − 8 keV and 8 − 28 keV luminosities using the 7 Ms Chandra X-ray image. Nearly all of the ALMA sources detected at 0.5 − 2 keV are consistent with a known X-ray luminosity to 850 µm flux relation for star-forming galaxies, while most of those detected at 2−7 keV are moderate luminosity AGNs that lie just above the 2−7 keV detection threshold. The latter largely have substantial obscurations of log N H = 23 − 24 cm −2 , but two of the high-redshift candidates may even be Compton thick.

SCUBA-2 Ultra Deep Imaging EAO Survey (Studies). III. Multiwavelength Properties, Luminosity Functions, and Preliminary Source Catalog of 450 μm Selected Galaxies

“…with the majority at z 3. On the other hand, the median redshift of 850-µm detected 450-µm sources is z = 2.30 +0.27 −0.26 with a 16th to 84th percentile range of 1.6 to 3.0, which is in good agreement with previous studies of 850-µm sources (Simpson et al , 2017Dunlop et al 2017;Cowie et al 2018). To gain insight into the redshift distribution of our entire sample, we assume that the 46 sources without 24-µm or radio identifications are at a median redshift of z = 3 ( §3.3).…”

“…We note that the sub-millimeter catalogs used in these works are biased toward brighter SMGs, since their catalogs are all from single-dish submillimeter surveys that have a typical angular resolution of 10 -20 and require radio counterparts. On the other hand, our estimated AGN fraction is more consistent with the ALMA-based estimate from ALESS (17 +16 −6 %; Wang et al 2013), ALMA follow-up observations in S2CLS UDS program AS2UDS (8-28%; Stach et al 2019), and ALMA follow-up observations in SCUBA-2 850-µm survey (∼ 6%; Cowie et al 2018). A trend of higher AGN fraction for SMG population with brighter 870-µm flux density was previously observed , which would imply that brighter SMGs are more likely to host AGNs.…”

An ALMA survey of the SCUBA-2 CLS UDS field: physical properties of 707 sub-millimetre galaxies

“…CDFS from Cowie et al (2018), which show a similar trend. We note that there are 108 SMGs in our sample that are undetected in the K-band (K > 25.7).…”

Extended Hα over compact far-infrared continuum in dusty submillimeter galaxies

“…On the other hand, the more interesting question is perhaps why the A V values agree in the lower infrared luminosity end, despite the spatial mismatches. Based on da Cunha et al (2008Cunha et al ( , 2015, magphys adopts a two-component model (birth cloud and diffuse ISM) to describe the attenuation of stellar emission at the UV-to-NIR regime. Since the UV-to-NIR emissions largely originate from the stars in the diffuse ISM, by increasing the attenuation in the birth clouds, it is possible to boost the infrared luminosity without significantly increasing the total attenuation, which is A V .…”