We present ALMA 870 µm (345 GHz) data for 49 high redshift (0.47< z <2.85), luminous (11.7 < log(L bol /L ) < 14.2) radio-powerful AGN, obtained to constrain cool dust emission from starbursts concurrent with highly obscured radiative-mode black hole (BH) accretion in massive galaxies which possess a small radio jet. The sample was selected from WISE with extremely steep (red) midinfrared (MIR) colors and with compact radio emission from NVSS/FIRST. Twenty-six sources are detected at 870 µm, and we find that the sample has large mid-to far-infrared luminosity ratios consistent with a dominant and highly obscured quasar. The rest-frame 3 GHz radio powers are 24.7 < log(P 3.0GHz /W Hz −1 ) < 27.3, and all sources are radio-intermediate or radio-loud. BH mass estimates are 7.7 < log(M BH /M ) < 10.2. The rest frame 1-5 µm SEDs are very similar to the "Hot DOGs" (Hot Dust Obscured Galaxies), and steeper (redder) than almost any other known extragalactic sources. ISM masses estimated for the ALMA detected sources are 9.9 < log(M ISM /M ) <11.75 assuming a dust temperature of 30K. The cool dust emission is consistent with star formation rates (SFRs) reaching several thousand M yr −1 , depending on the assumed dust temperature, however we cannot rule out the alternative that the AGN powers all the emission in some cases. Our best constrained source has radiative transfer solutions with ∼ equal contributions from an obscured AGN and a young (10-15 Myr) compact starburst.

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will observe several Deep Drilling Fields (DDFs) to a greater depth and with a more rapid cadence than the main survey. In this paper, we describe the “DeepDrill” survey, which used the Spitzer Space Telescope Infrared Array Camera (IRAC) to observe three of the four currently defined DDFs in two bands, centered on 3.6 μm and 4.5 μm. These observations expand the area which was covered by an earlier set of observations in these three fields by the Spitzer Extragalactic Representative Volume Survey (SERVS). The combined DeepDrill and SERVS data cover the footprints of the LSST DDFs in the Extended Chandra Deep Field–South field (ECDFS), the ELAIS-S1 field (ES1), and the XMM-Large-Scale Structure Survey field (XMM-LSS). The observations reach an approximate 5σ point-source depth of 2 μJy (corresponding to an AB magnitude of 23.1; sufficient to detect a 1011M⊙ galaxy out to z≈ 5) in each of the two bands over a total area of ≈ 29deg2. The dual-band catalogues contain a total of 2.35 million sources. In this paper we describe the observations and data products from the survey, and an overview of the properties of galaxies in the survey. We compare the source counts to predictions from the shark semi-analytic model of galaxy formation. We also identify a population of sources with extremely red ([3.6]-[4.5] &gt;1.2) colours which we show mostly consists of highly-obscured active galactic nuclei.

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We combine a deep 0.5 deg 2 , 1.4 GHz deep radio survey in the Lockman Hole with infrared and optical data in the same field, including the SERVS and UKIDSS near-infrared surveys, to make the largest study to date of the host galaxies of radio sources with typical radio flux densities ∼ 50 µJy. 87% (1274/1467) of radio sources have identifications in SERVS to AB ≈ 23.1 at 3.6 or 4.5µm, and 9% are blended with bright objects (mostly stars), leaving only 4% (59 objects) which are too faint to confidently identify in the near-infrared. We are able to estimate photometric redshifts for 68% of the radio sources. We use mid-infrared diagnostics to show that the source population consists of a mixture of star forming galaxies, rapidly accreting (cold mode) AGN and low accretion rate, hot mode AGN, with neither AGN nor starforming galaxies clearly dominating. We see the breakdown in the K − z relation in faint radio source samples, and show that it is due to radio source populations becoming dominated by sources with radio luminosities ∼ 10 23 WHz −1 . At these luminosities, both the star forming galaxies and the cold mode AGN have hosts with stellar luminosities about a factor of two lower than those of hot mode AGN, which continue to reside in only the most massive hosts. We show that out to at least z ∼ 2, galaxies with stellar masses > 10 11.5 M ⊙ have a radio-loud fraction up to ∼ 30%. This is consistent with there being a sufficient number of radio sources that radio-mode feedback could play a role in galaxy evolution.