We present the results of the first, deep ALMA imaging covering the full 4.5 arcmin 2 of the HUDF imaged with WFC3/IR on HST. Using a 45-pointing mosaic, we have obtained a homogeneous 1.3-mm image reaching σ 1.335 µJy, at a resolution of 0.7 arcsec. From an initial list of 50 > 3.5σ peaks, a rigorous analysis confirms 16 sources with S 1.3 > 120 µJy. All of these have secure galaxy counterparts with robust redshifts ( z = 2.15). Due to the unparalleled supporting data, the physical properties of the ALMA sources are well constrained, including their stellar masses (M * ) and UV+FIR star-formation rates (SFR). Our results show that stellar mass is the best predictor of SFR in the high-redshift Universe; indeed at z ≥ 2 our ALMA sample contains 7 of the 9 galaxies in the HUDF with M * ≥ 2 × 10 10 M , and we detect only one galaxy at z > 3.5, reflecting the rapid drop-off of high-mass galaxies with increasing redshift. The detections, coupled with stacking, allow us to probe the redshift/mass distribution of the 1.3-mm background down to S 1.3 10 µJy. We find strong evidence for a steep star-forming 'main sequence' at z 2, with SFR ∝ M * and a mean specific SFR 2.2 Gyr −1 . Moreover, we find that 85% of total star formation at z 2 is enshrouded in dust, with 65% of all star formation at this epoch occurring in high-mass galaxies (M * > 2 × 10 10 M ), for which the average obscured:unobscured SF ratio is 200. Finally, we revisit the cosmic evolution of SFR density; we find this peaks at z 2.5, and that the star-forming Universe transits from primarily unobscured to primarily obscured at z 4.

The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with a unique combination of high angular resolution (≈2 5), sensitivity (a 1σ goal of 70 μJy/beam in the coadded data), full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). The first observations began in 2017 September, and observing for the survey will finish in 2024. VLASS will use approximately 5500 hr of time on the Karl G. Jansky Very Large Array (VLA) to cover the whole sky visible to the VLA (decl. >−40°), a total of 33 885deg 2. The data will be taken in three epochs to allow the discovery of variable and transient radio sources. The survey is designed to engage radio astronomy experts, multi-wavelength astronomers, and citizen scientists alike. By utilizing an "on the fly" interferometry mode, the observing overheads are much reduced compared to a conventional pointed survey. In this paper, we present the science case and observational strategy for the survey, and also results from early survey observations.

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTWe present ;0 4 resolution extinction-independent distributions of star formation and dust in 11 star-forming galaxies (SFGs) at z=1.3-3.0. These galaxies are selected from sensitive blank-field surveys of the 2′×2′ Hubble Ultra-Deep Field at λ=5 cm and 1.3 mm using the Karl G. Jansky Very Large Array and Atacama Large Millimeter/submillimeter Array. They have star formation rates (SFRs), stellar masses, and dust properties representative of massive main-sequence SFGs at z∼2. Morphological classification performed on spatially resolved stellar mass maps indicates a mixture of disk and morphologically disturbed systems; half of the sample harbor X-ray active galactic nuclei (AGNs), thereby representing a diversity of z∼2 SFGs undergoing vigorous mass assembly. We find that their intense star formation most frequently occurs at the location of stellar-mass concentration and extends over an area comparable to their stellar-mass distribution, with a median diameter of 4.2±1.8 kpc. This provides direct evidence of galaxy-wide star formation in distant blank-field-selected mainsequence SFGs. The typical galactic-average SFR surface density is 2.5 M e yr −1 kpc −2 , sufficiently high to drive outflows. In X-ray-selected AGN where radio emission is enhanced over the level associated with star formation, the radio excess pinpoints the AGNs, which are found to be cospatial with star formation. The median extinctionindependent size of main-sequence SFGs is two times larger than those of bright submillimeter galaxies, whose SFRs are 3-8 times larger, providing a constraint on the characteristic SFR (∼300 M e yr −1 ) above which a significant population of more compact SFGs appears to emerge.

NGC 1266 is a nearby lenticular galaxy that harbors a massive outflow of molecular gas powered by the mechanical energy of an active galactic nucleus (AGN). It has been speculated that such outflows hinder star formation (SF) in their host galaxies, providing a form of feedback to the process of galaxy formation. Previous studies, however, indicated that only jets from extremely rare, high power quasars or radio galaxies could impart significant feedback on their hosts. Here we present detailed observations of the gas and dust continuum of NGC 1266 at millimeter wavelengths. Our observations show that molecular gas is being driven out of the nuclear region atṀ out ≈ 110 M ⊙ yr −1 , of which the vast majority cannot escape the nucleus. Only 2 M ⊙ yr −1 is actually capable of escaping the galaxy. Most of the molecular gas that remains is very inefficient at forming stars. The far-infrared emission is dominated by an ultra-compact ( 50 pc) source that could either be powered by an AGN or by an ultra-compact starburst. The ratio of the SF surface density (Σ SFR ) to the gas surface density (Σ H2 ) indicates that SF is suppressed by a factor of ≈ 50 compared to normal star-forming galaxies if all gas is forming stars, and ≈150 for the outskirt (98%) dense molecular gas if the central region is is powered by an ultra-compact starburst. The AGN-driven bulk outflow could account for this extreme suppression by hindering the fragmentation and gravitational collapse necessary to form stars through a process of turbulent injection. This result suggests that even relatively common, low-power AGNs are able to alter the evolution of their host galaxies as their black holes grow onto the M-σ relation.