- ID:
- ivo://CDS.VizieR/J/A+A/637/A64
- Title:
- Cygnus OB2 e-MERLIN 21cm survey (COBRaS)
- Short Name:
- J/A+A/637/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The role of massive stars is central to an understanding of galactic ecology. It is important to establish the details of how massive stars provide radiative, chemical, and mechanical feedback in galaxies. Central to these issues is an understanding of the evolution of massive stars, and the critical role of mass loss via strongly structured winds and stellar binarity. Ultimately, and acting collectively, massive stellar clusters shape the structure and energetics of galaxies. We aim to conduct high-resolution, deep field mapping at 21cm of the core of the massive Cygnus OB2 association and to characterise the properties of the massive stars and colliding winds at this waveband. We used seven stations of the e-MERLIN radio facility, with its upgraded bandwidth and enhanced sensitivity to conduct a 21cm census of Cygnus OB2. Based on 42 hours of observations, seven overlapping pointings were employed over multiple epochs during 2014 resulting in 1{sigma} sensitivities down to ~21{mu}Jy and a resolution of ~180mas. A total of 61 sources are detected at 21cm over a ~0.48{deg}x0.48{deg} region centred on the heart of the Cyg OB2 association. Of these 61 sources, 33 are detected for the first time. We detect a number of previously identified sources including four massive stellar binary systems, two YSOs, and several known X-ray and radio sources. We also detect the LBV candidate (possible binary system) and blue hypergiant star of Cyg OB2 #12. The 21cm observations secured in the COBRaS Legacy project provide data to constrain conditions in the outer wind regions of massive stars; determine the non-thermal properties of massive interacting binaries; examine evidence for transient sources, including those associated with young stellar objects; and provide unidentified sources that merit follow-up observations. The 21cm data are of lasting value and will serve in combination with other key surveys of Cyg OB2, including Chandra and Spitzer.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/472/557
- Title:
- Cygnus OB2 region 610MHz sources
- Short Name:
- J/A+A/472/557
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The modern generation of Cherenkov telescopes has revealed a new population of gamma-ray sources in the Galaxy. Some of them have been identified with previously known X-ray binary systems while other remain without clear counterparts a lower energies. Our initial goal here was reporting on extensive radio observations of the first extended and yet unidentified source, namely TeV J2032+4130. This object was originally detected by the HEGRA telescope in the direction of the Cygnus OB2 region and its nature has been a matter of debate during the latest years. The situation has become more complex with the Whipple and MILAGRO telescopes new TeV detections in the same field which could be consistent with the historic HEGRA source, although a different origin cannot be ruled out. We aim to pursue our radio exploration of the TeV J2032+4130 position that we initiated in a previous paper but taking now into account the latest results from new Whipple and MILAGRO TeV telescopes. The data presented here are an extended follow up of our previous work.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A1
- Title:
- Cygnus-X CO and SiO outflows datacubes
- Short Name:
- J/A+A/570/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a PdBI study of six massive dense cores in Cygnus-X, with CO (2-1) and SiO (2-1) emission. We studied the outflows of the individual protostars with CO (Duarte-Cabral et al., 2013A&A...558A.125D), and investigated the interstellar shocks responsible for the SiO emission (in Duarte-Cabral et al. 2014A&A...570A...1D).
- ID:
- ivo://CDS.VizieR/J/other/PASA/19.455
- Title:
- Damped Lyman alpha absorption of QSOs
- Short Name:
- J/other/PASA/19.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of the 322 damped Lyman alpha absorbers taken from the literature. All damped Lyman alpha absorbers are included, with no selection on redshift or quasar magnitude. Of these, 123 are candidates and await confirmation using high resolution spectroscopy. For all 322 objects we catalogue the radio properties of the background quasars, when known. Around 60 quasars have radio flux densities above 0.1Jy and approximately half of these have optical magnitudes brighter than V=18. This compilation should prove useful in several areas of extragalactic/cosmological research.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/158
- Title:
- Dark molecular gas in the Galaxy II. Perseus arm
- Short Name:
- J/ApJ/883/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results from a new, highly sensitive ({Delta}T_mb_~3mK) survey for thermal OH emission at 1665 and 1667MHz over a dense, 9x9pix grid covering a 1{deg}x1{deg} patch of sky in the direction of l=105.00{deg}, b=+2.50{deg} toward the Perseus spiral arm of our Galaxy. We compare our Green Bank Telescope 1667MHz OH results with archival ^12^CO(1-0) observations from the Five College Radio Astronomy Observatory Outer Galaxy Survey within the velocity range of the Perseus Arm at these galactic coordinates. Out of the 81 statistically independent pointings in our survey area, 86% show detectable OH emission at 1667MHz, and 19% of them show detectable CO emission. We explore the possible physical conditions of the observed features using a set of diffuse molecular cloud models. In the context of these models, both OH and CO disappear at current sensitivity limits below an A_v_ of 0.2, but the CO emission does not appear until the volume density exceeds 100-200cm^-3^. These results demonstrate that a combination of low column density A_v_ and low volume density n_H_ can explain the lack of CO emission along sight lines exhibiting OH emission. The 18cm OH main lines, with their low critical density of n*~1cm^-3^, are collisionally excited over a large fraction of the quiescent galactic environment and, for observations of sufficient sensitivity, provide an optically thin radio tracer for diffuse H_2_.
- ID:
- ivo://CDS.VizieR/J/A+A/582/A68
- Title:
- Database of circumstellar OH masers
- Short Name:
- J/A+A/582/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new database of circumstellar OH masers at 1612, 1665, and 1667MHz in the Milky Way galaxy. The database (version 2.4) contains 13655 observations and 2341 different stars detected in at least one transition. Detections at 1612MHz are considered to be complete until the end of 2014 as long as they were published in refereed papers. Detections of the main lines (1665 and 1667MHz) and non-detections in all transitions are included only if published after 1983. The database contains flux densities and velocities of the two strongest maser peaks, the expansion velocity of the shell, and the radial velocity of the star. Links are provided for about 100 stars (<5% of all stars with OH masers) to interferometric observations and monitoring programs of the maser emission published since their beginnings in the 1970s. Access to the database is possible over the Web (www.hs.uni-hamburg.de/maserdb), allowing cone searches for individual sources and lists of sources. A general search is possible in selected regions of the sky and by defining ranges of flux densities and/or velocities. Alternative ways to access the data are via the German Virtual Observatory and the CDS.
- ID:
- ivo://CDS.VizieR/J/A+A/653/A53
- Title:
- DEATHSTAR. II. The S-type
- Short Name:
- J/A+A/653/A53
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the re-calibrated and re-imaged fits-cubes of the second set of data from the DEATHSTAR project (DEtermining Accurate mass-loss rates for THermally pulsing AGB STARs, www.astro.uu.se/deathstar): the S-type stars. Fifteen S-type southern AGB stars were mapped in Bands 6 and 7 with the Atacama Compact Array (ACA). The generated beams have sizes of 4-8 and 3-6-arcseconds in Band 6 and 7, respectively. The rms noise level reached is typically 50-70 and 100-150mJy/beam in Band 6 and 7, respectively. The beam sizes and rms values for each source are listed in the paper together with the description of the reduction process, the analysis of the cubes and tentative line detections.
- ID:
- ivo://CDS.VizieR/J/A+A/640/A133
- Title:
- DEATHSTAR. Nearby AGB stars with ALMA ACA
- Short Name:
- J/A+A/640/A133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the re-calibrated and re-imaged fits-cubes of the first set of data from the DEATHSTAR project (DEtermining Accurate mass-loss rates for THermally pulsing AGB STARs, www.astro.uu.se/deathstar). Forty-two southern AGB stars, 21 carbon stars and 21 M-type stars, were mapped in Bands 6 and 7 with the Atacama Compact Array (ACA). Source selection, detected line emission, data calibration procedures etc. are described in detail in the paper. The beams are typically 4-8 and 3-5-arcseconds in Band 6 and 7, respectively. The rms noise level reached is typically 50-70 and 100-150mJy/beam in Band 6 and 7, respectively. More exact beam sizes and rms values for each source are listed in the paper together with tentative line detections.
- ID:
- ivo://CDS.VizieR/J/AJ/132/2409
- Title:
- Deep ATLAS radio observations of CDFS
- Short Name:
- J/AJ/132/2409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the Australia Telescope Large Area Survey, which consists of deep radio observations of a 3.7deg^2^ field surrounding the Chandra Deep Field-South, largely coincident with the infrared Spitzer Wide-Area Infrared Extragalactic (SWIRE) Survey. We also list cross-identifications to infrared and optical photometry data from SWIRE, and ground-based optical spectroscopy. A total of 784 radio components are identified, corresponding to 726 distinct radio sources, nearly all of which are identified with SWIRE sources. Of the radio sources with measured redshifts, most lie in the redshift range 0.5-2 and include both star-forming galaxies and active galactic nuclei. We identify a rare population of infrared-faint radio sources that are bright at radio wavelengths but are not seen in the available optical, infrared, or X-ray data. Such rare classes of sources can only be discovered in wide, deep surveys such as this.
- ID:
- ivo://CDS.VizieR/J/MNRAS/404/1005
- Title:
- Deep 15GHz survey (9C continued)
- Short Name:
- J/MNRAS/404/1005
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 9C survey of radio sources with the Ryle Telescope at 15.2GHz was set up to survey the fields of the cosmic microwave background telescope, the Very Small Array. In our first paper we described three regions of the survey, constituting a total area of to a completeness limit of ~25mJy. Here we present results from series of deeper regions, amounting to an area of 115deg^2^ complete to ~10mJy and of 29deg^2^ complete to ~5.5mJy. The compound source catalogue contains a total of 643 sources.