- ID:
- ivo://nasa.heasarc/vla23901p4
- Title:
- VLA A2390 Cluster of Galaxies 1.4-GHz Source Catalog
- Short Name:
- VLA23901P4
- Date:
- 18 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the 1.4-GHz source catalog for the field of the cluster of galaxies A2390 as observed with the Very Large Array (VLA). This is one of the deepest radio images of a cluster field ever taken. The image covers an area of 34' x 34' with a synthesized beam of ~1.4" and a noise level of ~5.6 µJy (µJy) near the field center. In the reference paper, the authors construct differential number counts for the central regions (radius < 16') of this cluster, and find that the faint (S<sub>1.4GHz</sub> < 3 mJy) counts of A2390 are roughly consistent with the lowest blank field number counts. Their analyses indicate that the number counts are primarily from field radio galaxies. The authors suggest that the disagreement of their number counts for this cluster with those from a similarly deep observation of A370 that was also presented in the reference paper can be largely attributed to cosmic variance. The authors observed the A2390 cluster field with the VLA in the A configuration for ~31.4hr on-source during 2008 October. The field center is located at 21:53:36 +17:41:52 (J2000). This table was created by the HEASARC in August 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/202/2/">CDS Catalog J/ApJS/202/2/</a> file table2.dat. This file contained 699 entries for sources detected at 1.4 GHz in the A370 field, as well as 524 entries for sources detected at 1.4 GHz in the A2390 field. Only the latter are included in this HEASARC table, while the former can be found in the HEASARC's <a href="vla3701p4.html">VLA3701P4</a> table. This is a service provided by NASA HEASARC .
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/802/69
- Title:
- VLA, ALMA and SMA monitoring of Sgr A*
- Short Name:
- J/ApJ/802/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report new observations with the Very Large Array, Atacama Large Millimeter Array, and Submillimeter Array at frequencies from 1.0 to 355GHz of the Galactic Center black hole, Sagittarius A*. These observations were conducted between 2012 October and 2014 November. While we see variability over the whole spectrum with an amplitude as large as a factor of 2 at millimeter wavelengths, we find no evidence for a change in the mean flux density or spectrum of Sgr A* that can be attributed to interaction with the G2 source. The absence of a bow shock at low frequencies is consistent with a cross-sectional area for G2 that is less than 2x10^29^cm2. This result fits with several model predictions including a magnetically arrested cloud, a pressure-confined stellar wind, and a stellar photosphere of a binary merger. There is no evidence for enhanced accretion onto the black hole driving greater jet and/or accretion flow emission. Finally, we measure the millimeter wavelength spectral index of Sgr A* to be flat; combined with previous measurements, this suggests that there is no spectral break between 230 and 690GHz. The emission region is thus likely in a transition between optically thick and thin at these frequencies and requires a mix of lepton distributions with varying temperatures consistent with stratification.
- ID:
- ivo://CDS.VizieR/J/A+A/453/911
- Title:
- VLA and IR observations of the S235A-B region
- Short Name:
- J/A+A/453/911
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on new aspects of the star-forming region S235AB revealed through high-resolution observations at radio and mid-infrared wavelengths. Using the Very Large Array, we carried out sensitive observations of S235AB in the cm continuum (6, 3.6, 1.3, and 0.7) and in the 22GHz water maser line. These were complemented with Spitzer Space Telescope Infrared Array Camera archive data to clarify the correspondence between radio and IR sources. We made also use of newly presented data from the Medicina water maser patrol, started in 1987, to study the variability of the water masers found in the region.
22884. VLA and XMM-EPIX maps of M83
- ID:
- ivo://CDS.VizieR/J/A+A/640/A109
- Title:
- VLA and XMM-EPIX maps of M83
- Short Name:
- J/A+A/640/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Reconnection heating has been considered as a potential source of the heating of the interstellar medium. In some galaxies, significant polarised radio emission has been found between the spiral arms. This emission has a form of 'magnetic arms' that resembles the spiral structure of the galaxy. Reconnection effects could convert some of the energy of the turbulent magnetic field into the thermal energy of the surrounding medium, leaving more ordered magnetic fields, as is observed in the magnetic arms. Sensitive radio and X-ray data for the grand-design spiral galaxy M 83 are used for a detailed analysis of the possible interactions of magnetic fields with hot gas, including a search for signatures of gas heating by magnetic reconnection effects. Magnetic field strengths and energies derived from the radio emission are compared with the parameters of the hot gas calculated from the model fits to sensitive X-ray spectra of the hot gas emission. The available X-ray data allowed us to distinguish two thermal components in the halo of M 83. We found slightly higher average temperatures of the hot gas in the interarm regions, which results in higher energies per particle and is accompanied by a decrease in the energy density of the magnetic fields. The observed differences in the energy budget between the spiral arms and the interarm regions suggest that, similar to the case of another spiral galaxy NGC 6946, we may be observing hints for gas heating by magnetic reconnection effects in the interarm regions. These effects, which act more efficiently on the turbulent component of the magnetic field, are expected to be stronger in the spiral arms. However, with the present data it is only possible to trace them in the interarm regions, where the star formation and the resulting turbulence is low.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/41
- Title:
- VLA & Chandra obs. of IRAS20126+4104 region
- Short Name:
- J/ApJS/219/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from Chandra ACIS-I and Karl G. Jansky Very Large Array 6cm continuum observations of the IRAS 20126+4104 massive star-forming region. We detect 150 X-ray sources within the 17'x17' ACIS-I field, and a total of 13 radio sources within the 9.2' primary beam at 4.9GHz. Among these observations are the first 6cm detections of the central sources reported by Hofner et al. (2007A&A...465..197H), namely, I20N1, I20S, and I20var. A new variable radio source is also reported. Searching the 2MASS archive, we identified 88 near-infrared (NIR) counterparts to the X-ray sources. Only four of the X-ray sources had 6cm counterparts. Based on an NIR color-color analysis and on the Besancon simulation of Galactic stellar populations, we estimate that approximately 80 X-ray sources are associated with this massive star-forming region. We detect an increasing surface density of X-ray sources toward the massive protostar and infer the presence of a cluster of at least 43 young stellar objects within a distance of 1.2pc from the massive protostar.
- ID:
- ivo://nasa.heasarc/vlacomacat
- Title:
- VLA Coma Cluster of Galaxies 1.4-GHz Source Catalog
- Short Name:
- VLACOMACAT
- Date:
- 18 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains results from deep 1.4-GHz Very Large Array (VLA) radio continuum observations of two ~0.5 deg<sup>2</sup> fields in the Coma cluster of galaxies. The two fields, "Coma 1" and "Coma 3", correspond to the cluster core and the southwest infall region, and were selected on account of abundant pre-existing multiwavelength data. In their most sensitive regions, the radio data reach 0.022 mJy (22 µJy) rms per 4.4" beam, sufficient to detect (at 5-sigma) Coma member galaxies with L<sub>1.4GHz</sub> = 1.3 x 10<sup>20</sup> W Hz<sup>-1</sup> (1.3 x 10<sup>27</sup> erg s<sup>-1</sup> Hz<sup>-1</sup>). The full catalog of radio detections at and above a 4.5-sigma significance threshold is presented herein; there are 1030 of these sources which are detected at >= 5 sigma, 628 of which are within the combined Coma 1 and Coma 3 area. The authors also provide optical identifications of the radio sources using data from the Sloan Digital Sky Survey (SDSS). The depth of the radio observations allows them to detect active galactic nuclei in cluster elliptical galaxies with M<sub>r</sub> < -20.5 (AB magnitudes), including radio detections for all cluster ellipticals with M<sub>r</sub> < -21.8. At fainter optical magnitudes (-20.5 < M<sub>r</sub> <~ -19), the radio sources are associated with star-forming galaxies with star formation rates as low as 0.1M_{sun}_ yr<sup>-1</sup>. The VLA observations were performed over five days in 2006 June as program code AM868. On each of the five days, the scheduled time was centered on the transit of Coma. This table was created by the HEASARC in December 2011 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/137/4436">CDS catalog J/AJ/137/4436</a> files table2.dat ('The Radio Source Catalog') and table3.dat ('Optical Counterparts to the Radio Sources'). It does not include table4.dat ('Rejected Optical Counterparts to the Radio Sources'). This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/A+A/602/A1
- Title:
- VLA-COSMOS 3 GHz Large Project
- Short Name:
- J/A+A/602/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the VLA-COSMOS 3GHz Large Project based on 384 hours of observations with the Karl G. Jansky Very Large Array (VLA) at 3GHz (10cm) toward the two square degree Cosmic Evolution Survey (COSMOS) field. The final mosaic reaches a median rms of 2.3 uJy/beam over the two square degrees at an angular resolution of 0.75". To fully account for the spectral shape and resolution variations across the broad (2GHz) band, we image all data with a multiscale, multifrequency synthesis algorithm. We present a catalog of 10,830 radio sources down to 5{sigma}, out of which 67 are combined from multiple components. Comparing the positions of our 3GHz sources with those from the Very Long Baseline Array (VLBA)-COSMOS survey, we estimate that the astrometry is accurate to 0.01" at the bright end (signal-to-noise ratio, S/N_3GHz_>20). Survival analysis on our data combined with the VLA-COSMOS 1.4GHz Joint Project catalog yields an expected median radio spectral index of {alpha}=-0.7. We compute completeness corrections via Monte Carlo simulations to derive the corrected 3GHz source counts. Our counts are in agreement with previously derived 3GHz counts based on single-pointing (0.087 square degrees) VLA data. In summary, the VLA-COSMOS 3GHz Large Project simultaneously provides the largest and deepest radio continuum survey at high (0.75") angular resolution to date, bridging the gap between last-generation and next-generation surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A2
- Title:
- VLA-COSMOS 3 GHz Large Project. II.
- Short Name:
- J/A+A/602/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the composition of the faint radio population selected from the VLA-COSMOS 3GHz Large Project, a radio continuum survey performed at 10 cm wavelength. The survey covers a 2.6 square degree area with a mean rms of ~2.3uJy/beam, cataloging 10,830 sources above 5sigma, and enclosing the full 2 square degree COSMOS field. By combining these radio data with optical, near-infrared (UltraVISTA), and mid-infrared (Spitzer/IRAC) data, as well as X-ray data (Chandra), we find counterparts to radio sources for ~93% of the total radio sample (in the unmasked areas of the COSMOS field, i.e., those not affected by saturated or bright sources in the optical to NIR bands), reaching out to z~6. We further classify the sources as star forming galaxies or AGN based on various criteria, such as X-ray luminosity, observed MIR color, UV-FIR spectral-energy distribution, rest-frame NUV-optical color corrected for dust extinction, and radio-excess relative to that expected from the hosts' star-formation rate. We separate the AGN into sub-samples dominated by low-to-moderate and moderate-to-high radiative luminosity AGN, candidates for high- redshift analogues to local low- and high-excitation emission line AGN, respectively. We study the fractional contributions of these sub-populations down to radio flux levels of ~11uJy at 3GHz (or ~20uJy at 1.4GHz assuming a spectral index of -0.7). We find that the dominant fraction at 1.4GHz flux densities above ~200uJy is constituted of low-to-moderate radiative luminosity AGN. Below densities of ~100uJy the fraction of star-forming galaxies increases to ~60%, followed by the moderate-to-high radiative luminosity AGN (~20%), and low-to-moderate radiative luminosity AGN (~20%). Based on this observational evidence, we extrapolate the fractions down to sensitivities of the Square Kilometer Array (SKA). Our estimates suggest that at the faint flux limits to be reached by the (Wide, Deep, and UltraDeep) SKA1 surveys, a selection based only on radio flux limits can provide a simple tool to efficiently identify samples highly (>75%) dominated by star-forming galaxies.
- ID:
- ivo://nasa.heasarc/vlacosxoid
- Title:
- VLA-COSMOS 3-GHz Large Project Multiwavelength Counterparts Catalog
- Short Name:
- VLACOSXOID
- Date:
- 18 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- In the reference paper, the authors study the composition of the faint radio population selected from the VLA-COSMOS 3-GHz Large Project, a radio continuum survey performed at 10-cm wavelength. The survey covers a 2.6 square degree area with a mean rms of ~2.3 µJy/beam (µJy/beam), cataloguing 10,830 sources above 5 sigma, and enclosing the full 2 square degree COSMOS field. By combining these radio data with optical, near-infrared (UltraVISTA), and mid-infrared (Spitzer/IRAC) data, as well as X-ray data (Chandra), the authors find counterparts to radio sources for ~93% of the total radio sample in the unmasked areas of the COSMOS field, i.e., those not affected by saturated or bright sources in the optical to near-IR (NIR) bands, reaching out to z ~ 6. They further classify the sources as star-forming galaxies or AGN based on various criteria, such as X-ray luminosity, observed mid-infrare (MIR) color, UV-far-infrared (FIR) spectral-energy distribution (SED), rest-frame near-ultraviolet (NUV)-optical color corrected for dust extinction, and radio-excess relative to that expected from the the hosts' star-formation rate. The authors separate the AGN into sub-samples dominated by low-to-moderate and moderate-to-high radiative luminosity AGN, i.e., candidates for high-redshift analogs to local low- and high-excitation emission line AGN, respectively. They study the fractional contributions of these sub-populations down to radio flux levels of ~11 uJy at 3 GHz (or ~20 uJy at 1.4 GHz assuming a spectral index of -0.7), and find that the dominant fraction at 1.4 GHz flux densities above ~200 uJy is constituted of low-to-moderate radiative luminosity AGN MLAGN). Below densities of ~100 uJy the fraction of star-forming galaxies (SFG) increases to ~60%, followed by the moderate-to-high radiative luminosity AGN (HLAGN) with ~20%, and MLAGN with ~20%. Based on this observational evidence, the authors extrapolate the fractions down to sensitivities of the Square Kilometer Array (SKA). Their estimates suggest that at the faint flux limits to be reached by the (Wide, Deep, and UltraDeep) SKA1 surveys, a selection based only on radio flux limits can provide a simple tool to efficiently identify samples highly (>75%) dominated by star-forming galaxies. This table contains the full list of 9,161 optical-MIR counterparts collected over the largest unmasked area accessible to each catalog, being 1.77, 1.73, and 2.35 square degrees for COSMOS2015, i-band, and IRAC catalogs, respectively. The catalog lists the counterpart IDs, properties, as well as the individual criteria used in this work to classify these radio sources. The authors note that complete, non-overlapping samples within a well defined, effective area of 1.77 square degrees (COSMOS2015 masked area flag_C15 = 0, can be formed by combining (i) HLAGN, MLAGN, and clean SFG samples, or, alternatively, (ii) the radio-excess and no-radio-excess samples. This table was created by the HEASARC in July 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/602/A2">CDS Catalog J/A+A/602/A2</a> file table1.dat, the VLA-COSMOS 3-GHz Large Project multiwavelength counterpart catalog. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/vlacos3ghz
- Title:
- VLA-COSMOS 3-GHz Large Project Source Catalog
- Short Name:
- VLACOS3GHZ
- Date:
- 18 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains some of the results from the VLA-COSMOS 3-GHz Large Project based on 384 hours of observations with the Karl G. Jansky Very Large Array (VLA) at 3 GHz (10 cm) toward the 2 square degree Cosmic Evolution Survey (COSMOS) field. The final mosaic reaches a median rms of 2.3 µJy (µJy) beam<sup>-1</sup> over the 2 square degrees at an angular resolution of 0.75 arcseconds. To fully account for the spectral shape and resolution variations across the broad (2-GHz) band, the authors imaged all the data with a multiscale, multifrequency synthesis algorithm. In this table, the catalog of 10,830 radio sources down to 5 sigma is presented, out of which 67 are combined from multiple components. Comparing the positions of these 3-GHz sources with those from the Very Long Baseline Array (VLBA)-COSMOS survey, the authors estimate that the astrometry is accurate to 0.01 arcseconds at the bright end (signal-to-noise ratio, S/N<sub>3GHz</sub> > 20). Survival analysis on these data combined with the VLA-COSMOS 1.4-GHz Joint Project catalog yields an expected median radio spectral index alpha = -0.7. The authors compute completeness corrections via Monte Carlo simulations to derive the corrected 3-GHz source counts. Their counts are in agreement with previously derived 3-GHz counts based on single-pointing (0.087 square degrees) VLA data. In summary, the VLA-COSMOS 3-GHz Large Project simultaneously provides the largest and deepest radio continuum survey at high (0.75") angular resolution to date, bridging the gap between last-generation and next-generation surveys. The catalog contains sources selected down to a 5-sigma (where sigma ~2.3 µJy/beam) threshold. This catalog can be used for statistical analyses, accompanied with the corrections given in the data & catalog release paper. All completeness and bias corrections and source counts presented in the paper were calculated using this sample. The total fraction of spurious sources in the COSMOS 2 sq.deg. field is below 2.7% within this catalog. However, an increase of spurious sources up to 24% at 5.0 < S/N < 5.5 is present (for details see Sec. 5.2., Fig. 17 and Table 3 of the reference paper). A subsample with a minimal spurious source fraction can be selected by requiring an additional cutoff S/N >= 5.5 for single component sources (MULTI=0). The total fraction of spurious sources in the COSMOS 2 sq.deg. field within such a selected sample is below 0.4%, and the fraction of spurious sources is below 3% even at the lowest S/N of 5.5. This table was created by the HEASARC in June 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/602/A1">CDS Catalog J/A+A/602/A1</a> file table1.dat, the VLA-COSMOS 3-GHz radio source catalog. This is a service provided by NASA HEASARC .
