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1791. VERA 22GHz Fringe Search Survey
ID:
ivo://CDS.VizieR/J/AJ/133/2487
Title:
VERA 22GHz Fringe Search Survey
Short Name:
J/AJ/133/2487
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents results of a survey search for bright compact radio sources at 22GHz with the VERA radio interferometer. Each source from a list of 2494 objects was observed in one scan for 2 minutes. The purpose of this survey was to find compact extragalactic sources bright enough at 22GHz to be useful as phase calibrators. Observed sources were either (1) within 6{deg} of the Galactic plane, or (2) within 11{deg} of the Galactic center, or (3) within 2{deg} of known water masers. Among the observed sources, 549 were detected, including 180 extragalactic objects that were not previously observed with the very long baseline interferometry technique. Estimates of the correlated flux densities of the detected sources are presented. It was found that the probability of detecting a 200mJy source with 120s of integration time is 60%.
1792. Very cold C-rich circumstellar envelopes
ID:
ivo://CDS.VizieR/J/A+A/267/515
Title:
Very cold C-rich circumstellar envelopes
Short Name:
J/A+A/267/515
Date:
21 Oct 2021
Publisher:
CDS
Description:
The paper develops a method for identification of very cold C-rich circumstellar envelopes (CSEs) in IR regions colder than region VII (i.e., larger value of IRAS flux ratio S25/S12), by reviewing the different criteria and by identifying C-rich CSEs in a sample of 228 bright IRAS sources. By using the results of OH surveys and catalogs together with the results of additional HCN/CO millimeter observations performed on critical classes of objects, a C/O classification is proposed for 94 percent of the sources with a good probability. It is shown that the low-resolution spectra by themselves are a reasonable and easy way to identify C-rich late AGB CSEs. For post-AGB object with cold CSEs, HCN and OH observations or visible/near IR spectroscopy are necessary.
1793. Very rich Abell clusters radio analysis
ID:
ivo://CDS.VizieR/J/ApJS/146/267
Title:
Very rich Abell clusters radio analysis
Short Name:
J/ApJS/146/267
Date:
21 Oct 2021
Publisher:
CDS
Description:
Radio observations were used to detect the "active" galaxy population within rich clusters of galaxies in a nonbiased manner that is not plagued by dust extinction or the K-correction. We present wide-field radio, optical (imaging and spectroscopy), and ROSAT All-Sky Survey (RASS, Cat. <IX/10>) X-ray data for a sample of 30 very rich Abell (R>=2) cluster with z<=0.25. The VLA radio data samples the ultrafaint radio (L(1.4GHz)>=2x10^22^W/Hz) galaxy population within these extremely rich clusters for galaxies with RMAG<=-21. This is the largest sample of low-luminosity 20 cm radio galaxies within rich Abell clusters collected to date.
1794. Very Small Array. Flux density at 33GHz
ID:
ivo://CDS.VizieR/J/MNRAS/360/340
Title:
Very Small Array. Flux density at 33GHz
Short Name:
J/MNRAS/360/340
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe the source subtraction strategy and observations for the extended Very Small Array (VSA), a cosmic microwave background interferometer operating at 33GHz. A total of 453 sources were monitored at 33GHz using a dedicated source subtraction baseline. 131 sources brighter than 20mJy were directly subtracted from the VSA visibility data. Some characteristics of the subtracted sources, such as spectra and variability, are discussed. The 33GHz source counts are estimated from a sample selected at 15GHz. The selection of VSA fields in order to avoid bright sources introduces a bias into the observed counts. This bias is corrected and the resulting source count is estimated to be complete in the flux-density range 20114mJy. The 33GHz source counts are used to calculate a correction to the VSA power spectrum for sources below the subtraction limit.
1795. Very Small Array. II. CMB at 34GHz
ID:
ivo://CDS.VizieR/J/MNRAS/341/1066
Title:
Very Small Array. II. CMB at 34GHz
Short Name:
J/MNRAS/341/1066
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have observed the cosmic microwave background (CMB) temperature fluctuations in eight fields covering three separated areas of sky with the Very Small Array at 34GHz. A total area of 101 square degrees has been imaged, with sensitivity on angular scales of 3.6{deg}-0.4{deg} (equivalent to angular multipoles l=150-900).
1796. VLA-A Array AL218 Texas Survey Source Snapshots (AL218)
ID:
ivo://mast.stsci/siap/al218
Title:
VLA-A Array AL218 Texas Survey Source Snapshots (AL218)
Short Name:
VLA.AL218
Date:
23 Jul 2020 19:30:09
Publisher:
Space Telescope Science Institute Archive
Description:
The VLA-A Texas Survey consists of a sample of objects extracted from the earlier Texas Interferometer 365 MHz Survey of radio sources covering a strip of sky from approximately -35.5 degrees declination to +71.5 degrees declination, and complete to flux densities of 0.25 Jy, with positional accuracies of ~1 arcsecond in RA and DEC. The sample is a subset of 71 sources drawn from the area of one optical Schmidt sky survey plate (covering ~6.5x6.5 degrees), Region S861, centered at approximately RA=190.640822109, DEC=-0.273834224277 (J2000), from the UK Schmidt SRC-J Survey. The Region S861 was initially chosen because it represented the combination of the deepest UK Schmidt plate material (the best optical survey material available at the time of the sample definition in 1989) and the highest galactic latitude, thereby emphasizing the extragalactic nature of the survey and also maximizing the likelihood of having more optical detections. Much more recently, the area of this plate has been covered by a number of important sky surveys including 2MASS, NRAO VLA FIRST, and the Sloan Digital Sky Survey (SDSS) which is now public. In particular, the availability of the Sloan Survey data provides 5-band ugriz color information at optical wavelengths, to depth of g,r=22.2.
1797. VLA, ALMA and SMA monitoring of Sgr A*
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.
1798. VLA and IR observations of the S235A-B region
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.
1799. 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.
1800. VLA & Chandra obs. of IRAS20126+4104 region
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.