- ID:
- ivo://CDS.VizieR/J/AJ/133/1331
- Title:
- Radio observation of HDFS at 2.5, 5.2, and 8.7GHz
- Short Name:
- J/AJ/133/1331
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep radio observations of a wide region centered on the Hubble Deep Field-South have been performed, providing one of the most sensitive sets of radio observations acquired on the Australia Telescope Compact Array to date. A central rms of ~10uJy is reached at four frequencies (1.4, 2.5, 5.2, and 8.7GHz). In this paper the full source catalogs from the 2.5, 5.2, and 8.7GHz observations are presented to complement Paper II (Huynh et al., 2005, Cat. J/AJ/130/1373) in this series, along with a detailed analysis of image quality and noise. We produce a consolidated catalog by matching sources across all four frequencies of our survey.
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- ID:
- ivo://CDS.VizieR/J/ApJ/895/23
- Title:
- Radio observation of the transient CSS161010
- Short Name:
- J/ApJ/895/23
- Date:
- 16 Mar 2022 00:23:37
- Publisher:
- CDS
- Description:
- We present X-ray and radio observations of the Fast Blue Optical Transient CRTS-CSS161010J045834-081803 (CSS161010 hereafter) at t=69-531days. CSS161010 shows luminous X-ray (Lx~5x1039erg/s) and radio (L{nu}~1029erg/s/Hz) emission. The radio emission peaked at ~100days post-transient explosion and rapidly decayed. We interpret these observations in the context of synchrotron emission from an expanding blast wave. CSS161010 launched a mildly relativistic outflow with velocity {Gamma}{beta}c>~0.55c at ~100days. This is faster than the non- relativistic AT 2018cow ({Gamma}{beta}c~0.1c) and closer to ZTF18abvkwla ({Gamma}{beta}c>~0.3c at 63days). The inferred initial kinetic energy of CSS161010 (Ek>~1051erg) is comparable to that of long gamma-ray bursts, but the ejecta mass that is coupled to the mildly relativistic outflow is significantly larger (~0.01-0.1M{odot}). This is consistent with the lack of observed {gamma}-rays. The luminous X-rays were produced by a different emission component to the synchrotron radio emission. CSS161010 is located at ~150Mpc in a dwarf galaxy with stellar mass M*~107M{sun} and specific star formation rate sSFR~0.3/Gyr. This mass is among the lowest inferred for host galaxies of explosive transients from massive stars. Our observations of CSS161010 are consistent with an engine-driven aspherical explosion from a rare evolutionary path of a H-rich stellar progenitor, but we cannot rule out a stellar tidal disruption event on a centrally located intermediate-mass black hole. Regardless of the physical mechanism, CSS161010 establishes the existence of a new class of rare (rate<0.4% of the local core-collapse supernova rate) H-rich transients that can launch mildly relativistic outflows.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A69
- Title:
- Radio observations of G074.11+00.11
- Short Name:
- J/A+A/630/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present molecular line and dust continuum observations of a Planck-detected cold cloud, G074.11+00.11. The cloud consists of a system of curved filaments and a central star-forming clump. The clump is associated with several infrared sources and H_2_O maser emission. We aim to determine the mass distribution and gas dynamics within the clump, to investigate if the filamentary structure seen around the clump repeats itself on a smaller scale, and to estimate the fractions of mass contained in dense cores and filaments. The velocity distribution of pristine dense gas can be used to investigate the global dynamical state of the clump, the role of filamentary inflows, filament fragmentation and core accretion. We use molecular line and continuum observations from single dish observatories and interferometry facilities to study the kinematics of the region. The molecular line observations show that the central clump may have formed as a result of a large-scale filament collision. The central clump contains three compact cores. Assuming a distance of 2.3kpc, based on Gaia observations and a three-dimensional extinction method of background stars, the mass of the central clump exceeds 700 solar masses, which is roughly 25% of the total mass of the cloud. Our virial analysis suggests that the central clump and all identified substructures are collapsing. We find no evidence for small-scale filaments associated with the cores. Our observations indicate that the clump is fragmented into three cores with masses in the range of [10,50] solar masses and that all three are collapsing. The presence of an H_2_O maser emission suggests active star formation. However the CO lines show only weak signs of outflows. We suggest that the region is young and any processes leading to star formation have just recently begun.
- ID:
- ivo://CDS.VizieR/J/ApJS/221/26
- Title:
- Radio observations of Galactic WISE HII regions
- Short Name:
- J/ApJS/221/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The WISE Catalog of Galactic H II Regions contains ~2000 H II region candidates lacking ionized gas spectroscopic observations. All candidates have the characteristic H II region mid-infrared morphology of WISE 12{mu}m emission surrounding 22{mu}m emission, and additionally have detected radio continuum emission. We here report Green Bank Telescope hydrogen radio recombination line (RRL) and radio continuum detections in the X-band (9GHz; 3cm) of 302 WISE H II region candidates (out of 324 targets observed) in the zone 225{deg}>=l>=-20{deg}, |b|<=6{deg}. Here we extend the sky coverage of our H II region Discovery Survey, which now contains nearly 800 HII regions distributed across the entire northern sky. We provide LSR velocities for the 302 detections and kinematic distances for 131 of these. Of the 302 new detections, 5 have (l, b, v) coordinates consistent with the Outer Scutum-Centaurus Arm (OSC), the most distant molecular spiral arm of the Milky Way. Due to the Galactic warp, these nebulae are found at Galactic latitudes >1{deg} in the first Galactic quadrant, and therefore were missed in previous surveys of the Galactic plane. One additional region has a longitude and velocity consistent with the OSC but lies at a negative Galactic latitude (G039.183-01.422; -54.9km/s). With Heliocentric distances >22kpc and Galactocentric distances >16kpc, the OSC H II regions are the most distant known in the Galaxy. We detect an additional three HII regions near ~=150{deg} whose LSR velocities place them at Galactocentric radii >19kpc. If their distances are correct, these nebulae may represent the limit to Galactic massive star formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/648/629
- Title:
- Radio observations of late M, L, and T dwarfs
- Short Name:
- J/ApJ/648/629
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I present radio observations of 90 dwarf stars and brown dwarfs of spectral type M5-T8. Three sources exhibit radio activity, in addition to the six objects previously detected in quiescence and outburst, leading to an overall detection rate of ~10% for objects later than M7.
- ID:
- ivo://CDS.VizieR/J/A+A/461/11
- Title:
- Radio observations of MYSO candidates
- Short Name:
- J/A+A/461/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Red MSX Source (RMS) survey is a multi-wavelength programme of follow-up observations designed to distinguish between genuine massive young stellar objects (MYSOs) and other embedded or dusty objects, such as ultra compact (UC) HII regions, evolved stars and planetary nebulae (PNe). We have identified nearly 2000 MYSOs candidates by comparing the colours of MSX and 2MASS point sources to those of known MYSOs. There are several other types of embedded or dust enshrouded objects that have similar colours as MYSOs and contaminate our sample. Two sources of contamination are from UCHII regions and PNe, both of which can be identified from the radio emission emitted by their ionised nebulae. In order to identify UCHII regions and PNe that contaminate our sample we have conducted high resolution radio continuum observations at 3.6 and 6cm of all southern MYSOs candidates (235{deg}<l<350{deg}) using the Australia Telescope Compact Array (ATCA). These observations have a spatial resolution of ~1-2" and typical image rms noise values of ~0.3mJy, sensitive enough to detect a HII region powered by a B0.5 star at the far side of the Galaxy. Of the 826 RMS sources observed we found 199 to be associated with radio emission, ~25% of the sample. The Galactic distribution, morphologies and spectral indices of the radio sources associated with the RMS sources are consistent with these sources being UCHII regions. Importantly, the 627 RMS sources for which no radio emission was detected are still potential MYSOs. In addition to the 802 RMS fields observed we present observations of a further 190 fields. These observations were made towards MSX sources that passed cuts in earlier versions of the survey, but were later excluded.
- ID:
- ivo://CDS.VizieR/J/A+A/299/238
- Title:
- Radio observations of PN candidates
- Short Name:
- J/A+A/299/238
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/274/895
- Title:
- Radio observations of South. PN Candidates
- Short Name:
- J/A+A/274/895
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IRAS sources having IR colours typical of planetary nebulae and located outside the Galactic bulge were observed in the radio continuum at 6cm with the Australian Compact Array (ACA). 18 new planetary nebulae were discovered among 89 candidates. The observations were performed in March and April 1991.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1358
- Title:
- Radio observations of the HDFS region. I
- Short Name:
- J/AJ/130/1358
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is the first of a series describing the results of the Australia Telescope Hubble Deep Field-South radio survey. The survey was conducted at four wavelengths, 20, 11, 6, and 3cm, over a 4 year period and achieves an rms sensitivity of about 10{mu}Jy at each wavelength. We describe the observations and data reduction processes and present data on radio sources close to the center of the Hubble Deep Field-South. We discuss in detail the properties of a subset of these sources. The sources include both starburst galaxies and galaxies powered by an active galactic nucleus and range in redshift from 0.1 to 2.2. Some of them are characterized by unusually high radio-to-optical luminosities, presumably caused by dust extinction.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1373
- Title:
- Radio observations of the HDFS region. II
- Short Name:
- J/AJ/130/1373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is part of a series describing the results from the Australia Telescope Hubble Deep Field-South (ATHDFS) survey obtained with the Australia Telescope Compact Array. This survey consists of observations at 1.4, 2.5, 5.2, and 8.7GHz, all centered on the Hubble Deep Field-South. Here we present the first results from the extended observing campaign at 1.4GHz. A total of 466 sources have been cataloged to a local sensitivity of 5{sigma} (11{mu}Jy rms). A source extraction technique is developed that (1) successfully excludes spurious sources from the final source catalogs and (2) accounts for the nonuniform noise in our image. A source catalog is presented, and the general properties of the 1.4GHz image are discussed. We also present source counts derived from our ATHDFS 1.4GHz catalog.
