- ID:
- ivo://CDS.VizieR/J/ApJ/727/20
- Title:
- The Megamaser Cosmology Project (MCP). III.
- Short Name:
- J/ApJ/727/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of H_2_O masers from circumnuclear disks in active galaxies for the Megamaser Cosmology Project (MCP) allow accurate measurement of the mass of supermassive black holes (BH) in these galaxies. We present the Very Long Baseline Interferometry images and kinematics of water maser emission in six active galaxies: NGC 1194, NGC 2273, NGC 2960 (Mrk 1419), NGC 4388, NGC 6264 and NGC 6323. We use the Keplerian rotation curves of these six megamaser galaxies, plus a seventh previously published, to determine accurate enclosed masses within the central ~0.3pc of these galaxies, smaller than the radius of the sphere of influence of the central mass in all cases.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/123/2402
- Title:
- The microJansky sky at 8.4GHz
- Short Name:
- J/AJ/123/2402
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from two deep radio integrations at 8.4 GHz using the Very Large Array. One of the fields, at 13h, +43{deg} (SA 13 field), has an rms noise level of 1.49{mu}Jy and is the deepest radio image yet made. Thirty-four sources in a complete sample were detected above 7.5{mu}Jy, and 25 are optically identified to a limit of I=25.8, using our deep Hubble Space Telescope and ground-based images. The radio sources are usually located within 0.5" (typically 5kpc) of a galaxy nucleus and generally have a diameter less than 2.5". We have also analyzed a complete flux density-limited sample at 8.4GHz of 89 sources from five deep radio surveys, including the Hubble deep and flanking fields, as well as the two new fields. Half of all the optical counterparts are with galaxies brighter than I=23mag, but 20% are fainter than I=25.5mag. There may be a small tendency for the microJansky radio sources to prefer multigalaxy systems. The distribution of the radio spectral index between 1.4 and 8.4GHz peaks at {alpha}~-0.75 (S~{nu}^+{alpha}^) with a median value of -0.6. The average spectral index becomes steeper (lower values) for sources below 35{mu}Jy and for sources identified with optical counterparts fainter than I=25.5mag. This correlation suggests that there is an increasing contribution from starburst galaxies compared to AGNs at lower radio flux densities and fainter optical counterparts. The differential radio count between 7.5 and 1000{mu}Jy has a slope of -2.11+/-0.13 and a surface density of 0.64 sources (arcmin)^-2^ with a flux density greater than 7.5{mu}Jy.
453. The Phoenix Survey
- ID:
- ivo://CDS.VizieR/J/MNRAS/306/708
- Title:
- The Phoenix Survey
- Short Name:
- J/MNRAS/306/708
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a deep Australia Telescope Compact Array (ATCA) radio survey covering an area of ~3deg^2^ to a 4{sigma} sensitivity of >=100mmJy at 1.4GHz, we study the nature of faint radio galaxies. About 50 per cent of the detected radio sources are identified with an optical counterpart revealed by CCD photometry to m_R=22.5mag. Near-infrared (K-band) data are also available for a selected sample of the radio sources, while spectroscopic observations have been carried out for about 40 per cent of the optically identified sample. These provide redshifts and information on the stellar content. Emission-line ratios imply that most of the emission-line sources are star-forming galaxies, with a small contribution (~10 per cent) from Sy1/Sy2 type objects. We also find a significant number of absorption-line systems, likely to be ellipticals. These dominate at high flux densities (>1mJy) but are also found at sub-mJy levels. Using the Balmer decrement we find a visual extinction A_V_=1.0 for the star-forming faint radio sources. This moderate reddening is consistent with the V-R and R-K colours of the optically identified sources. For emission-line galaxies, there is a correlation between the radio power and the Halpha luminosity, in agreement with the result of Benn et al. (1993MNRAS.263....9B). This suggests that the radio emission of starburst radio galaxies is a good indicator of star formation activity.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/55
- Title:
- The SPT-SZ catalog at 95, 150, and 220GHz
- Short Name:
- J/ApJ/900/55
- Date:
- 21 Mar 2022 09:29:14
- Publisher:
- CDS
- Description:
- We present a catalog of emissive point sources detected in the SPT-SZ survey, a contiguous 2530 square degree area surveyed with the South Pole Telescope (SPT) from 2008-2011 in three bands centered at 95, 150, and 220GHz. The catalog contains 4845 sources measured at a significance of 4.5{sigma} or greater in at least one band, corresponding to detections above approximately 9.8, 5.8, and 20.4mJy in 95, 150, and 220GHz, respectively. The spectral behavior in the SPT bands is used for source classification into two populations based on the underlying physical mechanisms of compact, emissive sources that are bright at millimeter wavelengths: synchrotron radiation from active galactic nuclei and thermal emission from dust. The latter population includes a component of high-redshift sources often referred to as submillimeter galaxies (SMGs). In the relatively bright flux ranges probed by the survey, these sources are expected to be magnified by strong gravitational lensing. The survey also contains sources consistent with protoclusters, groups of dusty galaxies at high redshift undergoing collapse. We cross-match the SPT-SZ catalog with external catalogs at radio, infrared, and X-ray wavelengths and identify available redshift information. The catalog splits into 3980 synchrotron-dominated and 865 dust-dominated sources, and we determine a list of 506 SMGs. Ten sources in the catalog are identified as stars. We calculate number counts for the full catalog, and synchrotron and dusty components, using a bootstrap method and compare our measured counts with models. This paper represents the third and final catalog of point sources in the SPT-SZ survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/917
- Title:
- The Super-CLASS GMRT catalogue - SCG
- Short Name:
- J/MNRAS/462/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of 325MHz Giant Metrewave Radio Telescope observations of a supercluster field, known to contain five Abell clusters at redshift z~0.2. We achieve a nominal sensitivity of 34uJy/beam towards the phase centre. We compile a catalogue of 3257 sources with flux densities in the range 183uJy-1.5Jy within the entire ~6.5deg^2^ field of view. Subsequently, we use available survey data at other frequencies to derive the spectral index distribution for a sub-sample of these sources, recovering two distinct populations - a dominant population which exhibit spectral index trends typical of steep-spectrum synchrotron emission, and a smaller population of sources with typically flat or rising spectra. We identify a number of sources with ultrasteep spectra or rising spectra for further analysis, finding two candidate high-redshift radio galaxies and three gigahertz-peaked-spectrum radio sources. Finally, we derive the Euclidean-normalized differential source counts using the catalogue compiled in this work, for sources with flux densities in excess of 223uJy. Our differential source counts are consistent with both previous observations at this frequency and models of the low-frequency source population. These represent the deepest source counts yet derived at 325MHz. Our source counts exhibit the well-known flattening at mJy flux densities, consistent with an emerging population of star-forming galaxies; we also find marginal evidence of a downturn at flux densities below 308uJy, a feature so far only seen at 1.4GHz.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1974
- Title:
- The VLA-COSMOS survey
- Short Name:
- J/AJ/128/1974
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 246 radio sources found in the central 1{deg} of the COSMOS field at 1.4GHz. The VLA pilot project data have a resolution of 1.9"x1.6" and an rms noise limit of ~25-100{mu}Jy/beam covering 0.837{deg}^2. About 20 radio sources are clearly extended, and most of them appear to be double-lobed radio galaxies. We find evidence for a cluster of seven radio galaxies with an extent of ~10' southeast of the COSMOS field center.
- ID:
- ivo://CDS.VizieR/J/ApJS/188/384
- Title:
- The VLA-COSMOS survey. IV.
- Short Name:
- J/ApJS/188/384
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the context of the VLA-COSMOS Deep project, additional VLA A array observations at 1.4GHz were obtained for the central degree of the COSMOS field and combined with the existing data from the VLA-COSMOS Large project. A newly constructed Deep mosaic with a resolution of 2.5" was used to search for sources down to 4{sigma} with 1{sigma}~12uJy/beam in the central 50'x50'. This new catalog is combined with the catalog from the Large project (obtained at 1.5"x1.4" resolution) to construct a new Joint catalog. All sources listed in the new Joint catalog have peak flux densities of >=5{sigma} at 1.5" and/or 2.5" resolution to account for the fact that a significant fraction of sources at these low flux levels are expected to be slightly resolved at 1.5" resolution. All properties listed in the Joint catalog, such as peak flux density, integrated flux density, and source size, are determined in the 2.5" resolution Deep image. In addition, the Joint catalog contains 43 newly identified multi-component sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/2590
- Title:
- The VLA-COSMOS Survey. V. 324MHz
- Short Name:
- J/MNRAS/443/2590
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 90cm Very Large Array imaging of the COSMOS field, comprising a circular area of 3.14 square degrees at 8.0"x6.0" angular resolution with an average rms of 0.5mJy/beam. The extracted catalogue contains 182 sources (down to 5.5{sigma}), 30 of which are multicomponent sources. Using Monte Carlo artificial source simulations, we derive the completeness of the catalogue, and we show that our 90cm source counts agree very well with those from previous studies. Using X-ray, NUV-NIR and radio COSMOS data to investigate the population mix of our 90cm radio sample, we find that our sample is dominated by active galactic nuclei. The average 90-20cm spectral index (S_{nu}_{prop.to}{nu}^{alpha}^, where S_{nu}_ is the flux density at frequency {nu} and {alpha} the spectral index) of our 90cm selected sources is -0.70, with an interquartile range from -0.90 to -0.53. Only a few ultra-steep-spectrum sources are present in our sample, consistent with results in the literature for similar fields. Our data do not show clear steepening of the spectral index with redshift. Nevertheless, our sample suggests that sources with spectral indices steeper than -1 all lie at z>~1, in agreement with the idea that ultra-steep-spectrum radio sources may trace intermediate-redshift galaxies (z>~1).
- ID:
- ivo://CDS.VizieR/J/ApJS/194/25
- Title:
- The VLBA calibrator search for the BeSSeL survey
- Short Name:
- J/ApJS/194/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a survey of radio continuum sources near the Galactic plane using the Very Long Baseline Array (VLBA). Our observations are designed to identify compact extragalactic sources of milliarcsecond size that can be used for parallax measurements in the Bar and Spiral Structure Legacy Survey. We selected point sources from the NVSS and CORNISH catalogs with flux densities above 30mJy and within 1.5{deg} of known maser targets. Of the 1529 sources observed, 199 were detected. For sources detected on three or more baselines, we determined accurate positions and evaluated their quality as potential calibrators. Most of the 1330 sources that were not detected with the VLBA are probably of extragalactic origin.
- ID:
- ivo://CDS.VizieR/J/ApJS/148/97
- Title:
- The WMAP First Year Source Catalog (WMAP1)
- Short Name:
- J/ApJS/148/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The WMAP mission has mapped the full sky to determine the geometry, content, and evolution of the universe. Full-sky maps are made in five microwave frequency bands to separate the temperature anisotropy of the cosmic microwave background (CMB) from foreground emission, including diffuse Galactic emission and Galactic and extragalactic point sources. We define masks that excise regions of high foreground emission, so CMB analyses can be carried out with minimal foreground contamination. We also present maps and spectra of the individual emission components, leading to an improved understanding of Galactic astrophysical processes.
