- ID:
- ivo://CDS.VizieR/J/ApJ/884/140
- Title:
- VLA obs. of the H2O maser source G25.65+1.05
- Short Name:
- J/ApJ/884/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The source G25.65+1.05 (RAFGL7009S, IRAS 18316-0602) is the least studied of the three regions of massive star formation known to show exceptionally powerful H_2_O maser bursts. We report spectral line observations of the H_2_O maser at 22GHz, the methanol maser transitions at 6.7, 12.2, and 44GHz, and the continuum in these same frequency bands with The Karl G. Jansky Very Large Array at the post-burst epoch of 2017. For the first time, maps of 22GHz H_2_O and 44GHz CH_3_OH maser spots are obtained and the absolute position of the 22GHz H_2_O bursting feature is determined with milliarcsecond precision. We detected four continuum components, three of which are closely spaced in a linear orientation, suggesting a physical link between them.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/133/77
- Title:
- VLA radio continuum survey of Seyfert galaxies
- Short Name:
- J/ApJS/133/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Very Large Array (VLA) to conduct a survey for radio continuum emission in the sample of 52 Seyfert nuclei selected from the optical spectroscopic galaxy catalog of Ho, Filippenko, & Sargent (1995, Cat. <J/ApJS/98/477>. This Seyfert sample is the most complete and least biased available, and, as such, it will be useful for a variety of statistical analyses. Here we present the observations, measurements, and an atlas of radio maps. The observations were made at 6 cm in the B array and at 20 cm in the A array, yielding matched angular resolutions of ~1". We detected 44 objects (85%) at 6 cm and 37 objects (71%) at 20 cm above a 3{sigma} threshold of 0.12mJy/beam. The sources have a wide range of radio powers (P~10^19^-10^25^W/Hz), spectral indices ({alpha}^20^_6_~+0.5 to 1), and linear sizes (L~few tens pc - 15kpc). The morphology of the radio emission is predominantly that of a compact core, either unresolved or slightly resolved, occasionally accompanied by elongated, jetlike features. Linearly polarized emission was detected at 6 cm in 12 sources, nine of which were also detected at 20 cm.
- ID:
- ivo://CDS.VizieR/J/ApJ/728/97
- Title:
- VLA rotation measures in the Galactic plane
- Short Name:
- J/ApJ/728/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have determined 194 Faraday rotation measures (RMs) of polarized extragalactic radio sources using new, multi-channel polarization observations at frequencies around 1.4GHz from the Very Large Array in the Galactic plane at 17{deg}<=l<=63{deg} and 205{deg}<=l<=253{deg}. This catalog fills in gaps in the RM coverage of the Galactic plane between the Canadian Galactic Plane Survey (CGPS; Taylor et al. 2003, Cat. VI/128; Brown et al. 2003, Cat. J/ApJS/145/213) and Southern Galactic Plane Survey (SGPS; Haverkorn et al. 2006ApJS..167..230H; Brown et al. 2007, Cat. J/ApJ/663/258).
- ID:
- ivo://CDS.VizieR/J/ApJ/740/65
- Title:
- VLA search for 5GHz radio transients
- Short Name:
- J/ApJ/740/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a 5GHz survey with the Very Large Array (VLA) and the expanded VLA, designed to search for short-lived (<~1day) transients and to characterize the variability of radio sources at milli-Jansky levels. A total sky area of 2.66deg^2^, spread over 141 fields at low Galactic latitudes (b~6-8{deg}), was observed 16 times with a cadence that was chosen to sample timescales of days, months, and years. Most of the data were reduced, analyzed, and searched for transients in near real-time. Interesting candidates were followed up using visible light telescopes (typical delays of 1-2hr) and the X-ray Telescope on board the Swift satellite. The final processing of the data revealed a single possible transient with a peak flux density of f_{nu}_~2.4mJy. Furthermore, we use the data to measure the source variability on timescales of days to years, and we present the variability structure function of 5GHz sources.
- ID:
- ivo://CDS.VizieR/J/ApJS/255/30
- Title:
- VLASS QL Ep.1 Catalog, CIRADA version
- Short Name:
- J/ApJS/255/30
- Date:
- 09 Feb 2022 14:56:38
- Publisher:
- CDS
- Description:
- The Very Large Array Sky Survey (VLASS) is observing the entire sky north of -40{deg} in the S-band (2-4GHz), with the highest angular resolution (2.5") of any all-sky radio continuum survey to date. VLASS will cover its entire footprint over three distinct epochs, the first of which has now been observed in full. Based on Quick Look images from this first epoch, we have created a catalog of 1.9x10^6 reliably detected radio components. Due to the limitations of the Quick Look images, component flux densities are underestimated by ~15% at S>3mJy/beam and are often unreliable for fainter components. We use this catalog to perform statistical analyses of the 3GHz radio sky. Comparisons with the Faint Images of the Radio Sky at Twenty cm survey (FIRST) show the typical 1.4-3GHz spectral index to be -0.71. The radio color-color distribution of point and extended components is explored by matching with FIRST and the LOFAR Two Meter Sky Survey. We present the VLASS source counts, dN/dS, which are found to be consistent with previous observations at 1.4 and 3GHz. Resolution improvements over FIRST result in excess power in the VLASS two-point correlation function at angular scales <7", and in 18% of active galactic nuclei associated with a single FIRST component being split into multi-component sources by VLASS.
- ID:
- ivo://CDS.VizieR/J/A+A/398/901
- Title:
- VLA survey at 6 cm in the Lockman Hole
- Short Name:
- J/A+A/398/901
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A deep radio image was obtained with the Very Large Array at 6cm in the Lockman Hole, during three runs of eleven hours each on January 16, 17 and 19, 1999 at 4835 and 4885MHz with a bandwidth of 50MHz in C configuration. From these data a catalogue of 63 radio sources was extracted, having a maximum distance of 10arcmin from the field center and a peak flux density greater than 4.5 times the local rms noise. The noise level in the central part of the field is ~11{mu}Jy.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/155
- Title:
- VLA survey for faint compact radio sources in ONC
- Short Name:
- J/ApJ/831/155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Karl G. Jansky Very Large Array 1.3, 3.6, and 6cm continuum maps of compact radio sources in the Orion Nebular Cluster (ONC). We mosaicked 34arcmin^2^ at 1.3cm, 70arcmin^2^ at 3.6cm and 109arcmin^2^ at 6cm, containing 778 near-infrared detected young stellar objects and 190 Hubble Space Telescope-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source, we fitted a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from submillimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3cm data, to search for and quantify the variability of our sources.
- ID:
- ivo://CDS.VizieR/J/ApJS/80/501
- Title:
- VLA survey of Abell clusters. II.
- Short Name:
- J/ApJS/80/501
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radio contour maps, models, and optical identifications for 130 radio galaxies in Abell clusters of galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/109/853
- Title:
- VLA survey of Abell clusters. IV.
- Short Name:
- J/AJ/109/853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the fourth in a series of papers describing an in depth study of a large statistical sample of radio galaxies in Abell clusters. This sample forms the basis of a detailed optical and radio study of the host galaxy properties, environments, and evolutionary models for radio galaxies as a class of objects. In this paper, we examine the radio detection statistics as a function of cluster morphological type, galaxy richness, and spatial location within the cluster galaxy distribution. These relationships are also parametrized as a function of radio power. The spatial distributions of the radio sources as a function of distance from the cluster center indicate that radio galaxies are preferentially located at small radii from the center of the cluster potential. This is observed as a factor of 2-3 excess over that predicted by a King-model surface-density distribution. The excess is higher in the upper radio power bin. This result is easily explained, however, from the spatial distribution of the brightest galaxies and the relationship between radio and optical luminosity. The sample is divided into richness classes 0, 1, and 2, according to Abell's criterion, and in two radio power ranges. While simple counting shows that richer clusters have more radio galaxies in both radio power bins, when the detections are scaled to the number of galaxies surveyed in each cluster, no significant correlations are found. This result implies that the number of radio galaxies detected simply scales with the number of galaxies surveyed. The higher galaxy density (and presumably higher ICM gas density) in richer clusters does not appear to affect the rate of radio source formation. The clusters are divided into Rood-Sastry and Bautz-Morgan morphological types. While it would appear that the more regular clusters have higher radio detection rates, when the classes are normalized to the number of galaxies, the radio detection rates are found to be identical regardless of cluster morphology. In conclusion, it is the optical properties of the host galaxy which most influence both the radio detection rate and the radio source properties. The cluster properties, galaxy density, and spatial location of the galaxy do not significantly affect the observed radio statistics.
- ID:
- ivo://CDS.VizieR/J/AJ/98/64
- Title:
- VLA survey of Abell clusters of galaxies I.
- Short Name:
- J/AJ/98/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a VLA survey at 20cm of a complete sample of nearby Abell clusters (D<=3). We have compiled an extensive catalog of cluster radio sources with S_20_>10mJy from a combination of our VLA observations and observations of similar resolution with the Westerbork Synthesis Radio Telescope (WSRT). Using these radio data and X-ray data from the Einstein observatory, we have analyzed the properties of these clusters. Unlike that previously suggested, no significant correlation is found between 20cm radio power and X-ray luminosity. There is weak evidence that richer clusters have a higher probability of radio emission. Based on Rood-Sastry morphological types of clusters, we do not find any strong evidence that regular-type clusters are statistically more likely to be radio loud than irregular-type clusters. However, Bautz-Morgan types I and II-III are found to have comparable radio-detection rates; but Bautz-Morgan Type III clusters are likely to have a lower radio-detection rate. A weak correlation between X-ray-cooling mass-accretion rates and radio powers was found for central, dominant galaxies in cooling-flow clusters. This might suggest that either cooling accretion directly fuels the central engine and/or cooling flows strongly interact with (e.g., confine) the radio plasma. In addition, radio sources associated with central dominant galaxies in cooling-flow clusters tend to be small in comparison with those in non-cooling-flow clusters. This might suggest that cooling flows tend to obstruct the propagation of radio jets from central, dominant galaxies.
