We present Atacama Large Millimeter/submillimeter Array (ALMA) observations from the 2014 Long Baseline Campaign in dust continuum and spectral line emission from the HL Tau region. The continuum images at wavelengths of 2.9, 1.3, and 0.87 mm have unprecedented angular resolutions of 0″. 075 (10 AU) to 0″. 025 (3.5 AU), revealing an astonishing level of detail in the circumstellar disk surrounding the young solar analog HL Tau, with a pattern of bright and dark rings observed at all wavelengths. By fitting ellipses to the most distinct rings, we measure precise values for the disk inclination (46 .72 0 .05 ± • •) and position angle (138 .02 0 .07).

18 days of MERLIN data and 42 h of A‐array VLA data at 1.4 GHz have been combined to image a 10‐arcmin field centred on the Hubble Deep Field (HDF). This area also includes the Hubble Flanking Fields (HFF). A complete sample of 92 radio sources with S1.4 > 40 μJy was detected using the VLA data alone and then imaged with the MERLIN+VLA combination. The combined images offer (i) higher angular resolution (synthesized beams of diameter 0.2–0.5 arcsec), (ii) improved astrometric accuracy, and (iii) improved sensitivity compared with VLA‐only data. The images are amongst the most sensitive yet made at 1.4 GHz, with rms noise levels of 3.3 μJy beam−1 in the 0.2‐arcsec images. Virtually all the sources are resolved, with angular sizes in the range 0.2 to 3 arcsec. The central 3‐arcmin square was imaged separately to search for sources down to 27 μJy. No additional sources were detected, indicating that sources fainter than 40 μJy are heavily resolved with MERLIN and must have typical angular sizes > 0.5 arcsec. Radio sources associated with compact galaxies have been used to align the HDF, the HFF and a larger CFHT optical field to the radio‐based International Celestial Reference Frame. The HST optical fields have been registered to <50 mas in the HDF itself, and to ≤150 mas in the outer parts of the HFF. We find a statistical association of very faint (≥2 μJy) radio sources with optically bright HDF galaxies down to ∼23 mag. Of the 92 radio sources above 40 μJy, ∼85 per cent are identified with galaxies brighter than I= 25 mag; the remaining 15 per cent are associated with optically faint systems close to or beyond the HFF (or even the HDF) limit. The high astrometric accuracy and the ability of radio waves to penetrate obscuring dust have led to the correct identification of several very red, optically faint systems, including the the strongest submillimetre source in the HDF, HDF 850.1. On the basis of their radio structures and spectra, 72 per cent (66 sources) can be classified as starburst or active galactic nucleus‐type systems; the remainder are unclassified. The proportion of starburst systems increases with decreasing flux density; below 100 μJy > 70 per cent of the sources are starburst‐type systems associated with major disc galaxies in the redshift range 0.3–1.3. Chandra detections are associated with 55 of the 92 radio sources, but their X‐ray flux densities do not appear to be correlated with the radio flux densities or morphologies. The most recent submillimetre results on the HDF and HFF do not provide any unambiguous identifications with these latest radio data, except for HDF 850.1, but suggest at least three strong candidates.

We report on sensitive radio observations made with the VLA at 8.5 GHz centered on the Hubble Deep Field (HDF). We collected data in the A, CnB, C, DnC, and D conÐgurations corresponding to angular resolutions ranging from to 10A. We detected 29 radio sources in a complete sample within 0A .3 of the HDF center and above a Ñux density limit of 9.0 kJy (5 p). Seven of these sources are located 4@ .6 within the HDF itself, while the remaining 22 sources are covered by the Hubble Ñanking Ðelds (HFFs) or ground-based optical images. All of the sources in the HDF are identiÐed with galaxies with a mean magnitude R \ 21.7, while the mean magnitude of the identiÐcations outside the HDF is R \ 22.1. One radio source in the HDF, which is just below our formal completeness level but is conÐrmed by independent 1.4 GHz observations, has no optical counterpart above the HDF limit of R \ 29. Three radio sources outside the HDF have no optical counterparts to R \ 27. Based on a radio and optical positional coincidence, we detected an additional 19 radio sources in this Ðeld (seven of which are contained in the HDF) with 6.3 kJy kJy (3.5 p) and R ¹ 25 but which are not included inThe microjansky radio sources are distributed over a wide range of redshifts (0.1 \ z \ 3) and have a typical monochromatic luminosity of about 1023 W Hz~1. The majority of the optical identiÐcations are with luminous galaxies at modest redshifts many with evidence for recent star for-, mation. The remainder are composed of a mixture of bright Ðeld elliptical galaxies and late-type galaxies with evidence of nuclear activity (LINERs and Seyfert galaxies) and nearby (z \ 0.2) Ðeld spiral galaxies. None of the radio sources in this survey are identiÐed with quasars or galactic stars.