- ID:
- ivo://CDS.VizieR/J/A+AS/73/103
- Title:
- The 64W part of the WRST Survey
- Short Name:
- J/A+AS/73/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a deep 92cm survey down to 4.5mJy (5{sigma}) carried out with the Westerbork Synthesis Radio Telescope (WSRT) of a field in Lynx, previously observed at three other radio frequencies: 6, 21, and 49cm. The observations, totalising 4*12h were made in the redundancy mode, which makes it possible to achieve a high dynamic range. In total, 384 sources above a 5{sigma} peak flux limit were detected, of which 337 form a complete sample.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/71/221
- Title:
- The 65W part of the WSRT 21 cm survey in Lynx
- Short Name:
- J/A+AS/71/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the field Lynx 3A, obtained at 21cm with 5{sigma} peak flux 85{mu}Jy using the 3-km array of the Westerbork Synthesis Radio Telescope for 16x12h periods during 1984, are reported. Details of the observations and the data reduction are given, and the results are presented in extensive tables and maps. A complete sample of 321 objects within the 0.5{deg} attenuation radius is selected from the 349 objects detected above 85{mu}Jy, and the 1.412GHz source counts down to 100{mu}Jy are found to be in good agreement with VLA surveys of similar depth. The median angular size of sources with total flux density between 350{mu}Jy and 10mJy is shown to be less than 10arcsec.
- ID:
- ivo://CDS.VizieR/J/A+A/638/A46
- Title:
- The XXL Survey. XLI. GMRT XXL-N 610MHz
- Short Name:
- J/A+A/638/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the space density evolution of active galactic nuclei (AGN) using the 610MHz radio survey of the XXL-North field, performed with the Giant Metrewave Radio Telescope (GMRT). The survey covers an area of 30.4deg^2^, with a beamsize of 6.5arcsec. The survey is divided into two parts, one covering an area of 11.9deg^2^ with 1{sigma} rms noise of 200uJy/beam and the other spanning 18.5deg^2^ with rms noise of 45uJy/beam. We extracted the catalog of radio components above 7. The catalog was cross-matched with a multi-wavelength catalog of the XXL-North field (covering about 80% of the radio XXL-North field) using a likelihood ratio method, which determines the counterparts based on their positions and their optical properties. The multi-component sources were matched visually with the aid of a computer code: Multi-Catalog Visual Cross-Matching (MCVCM). A flux density cut above 1mJy selects AGN hosts with a high purity in terms of star formation contamination based on the available source counts. After crossmatching and elimination of observational biases arising from survey incompleteness, the number of remaining sources was 1150. We constructed the rest-frame 1.4GHz radio luminosity functions of these sources using the maximum volume method. This survey allows us to probe luminosities of 23<~log(L1.4GHz[W/Hz])<~28 up to redshifts of z~=2.1. Our results are consistent with the results from the literature in which AGN are comprised of two differently evolving populations, where the high luminosity end of the luminosity functions evolves more strongly than the low-luminosity end.
1744. The Zelenchuk Surveys
- ID:
- ivo://CDS.VizieR/VIII/49
- Title:
- The Zelenchuk Surveys
- Short Name:
- VIII/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main catalog contains positions and flux densities for 8511 sources detected in the Zelenchuk 3.9 GHz Survey with declinations between 0 and 14 degrees. The survey was originally published in Amirkhanyan et al. 1989, MIR Publ., Moscow, and contained 8511 sources. The machine version has been cleaned from a few spurious sources by the authors. The angular resolution is (RA x DEC) 70"/cos(decl) x 50'. The survey is 95 percent complete to the limiting flux density 50 mJy, except near the boundaries of the declination zone. A supplementary catalogue of 2946 radio sources observed during Zelenchuk survey at 3.9 GHz in the flux density from 40 to 50 mJy within the declination range 0-14 degrees are presented. ratan is the first results of the deep search survey over a portion of the celestial sphere with the radio telescope RATAN-600 at several cm-wavelengths. The catalogue contains 691 radio sources at 3.9 GHz. Fluxes at the frequencies 3.9, 4.8, 7.5 and 11.2 GHz have been measured for the complete sample of the radio sources from the Zelenchuk survey. The sample contains all sources with S > 200 mJy in the 4-6 degree declination range.
- ID:
- ivo://CDS.VizieR/J/ApJ/810/14
- Title:
- Third catalog of LAT-detected AGNs (3LAC)
- Short Name:
- J/ApJ/810/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It is based on the third Fermi-LAT catalog (3FGL) of sources detected between 100MeV and 300GeV with a Test Statistic greater than 25, between 2008 August 4 and 2012 July 31. The 3LAC includes 1591 AGNs located at high Galactic latitudes (|b|>10{deg}), a 71% increase over the second catalog based on 2 years of data. There are 28 duplicate associations, thus 1563 of the 2192 high-latitude gamma-ray sources of the 3FGL catalog are AGNs. Most of them (98%) are blazars. About half of the newly detected blazars are of unknown type, i.e., they lack spectroscopic information of sufficient quality to determine the strength of their emission lines. Based on their gamma-ray spectral properties, these sources are evenly split between flat-spectrum radio quasars (FSRQs) and BL Lacs. The most abundant detected BL Lacs are of the high-synchrotron-peaked (HSP) type. About 50% of the BL Lacs have no measured redshifts. A few new rare outliers (HSP-FSRQs and high-luminosity HSP BL Lacs) are reported. The general properties of the 3LAC sample confirm previous findings from earlier catalogs. The fraction of 3LAC blazars in the total population of blazars listed in BZCAT remains non-negligible even at the faint ends of the BZCAT-blazar radio, optical, and X-ray flux distributions, which hints that even the faintest known blazars could eventually shine in gamma-rays at LAT-detection levels. The energy-flux distributions of the different blazar populations are in good agreement with extrapolation from earlier catalogs.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1163
- Title:
- Third VLBA calibrator survey: VCS3
- Short Name:
- J/AJ/129/1163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the third extension to the Very Long Baseline Array (VLBA) Calibrator Survey, containing 360 new sources not previously observed with Very Long Baseline Interferometry (VLBI). The survey, based on three 24 hour VLBA observing sessions, fills the areas on the sky above declination -45{deg} where the calibrator density is less than one source within a 4{deg} radius disk at any given direction. The positions were derived from astrometric analysis of the group delays determined at 2.3 and 8.6GHz frequency bands using the CALC/SOLVE software package. The VCS3 catalog of source positions, plots of correlated flux density versus length of projected baseline, and contour plots and FITS files of naturally weighted CLEAN images, as well as calibrated visibility function files, are available electronically from the Goddard Geodetic VLBI Group.
1747. THOR DR2 source list
- ID:
- ivo://CDS.VizieR/J/A+A/634/A83
- Title:
- THOR DR2 source list
- Short Name:
- J/A+A/634/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Galactic plane has been observed extensively by a large number of Galactic plane surveys from infrared to radio wavelengths at an angular resolution below 40". However, a 21cm line and continuum survey with comparable spatial resolution is lacking. The first half of THOR data (l=14.0{deg}-37.9{deg}, and l=47.1{deg}-51.2{deg}, |b|<=1.25{deg}) has been published in our data release 1 paper. With this data release 2 paper, we publish all the remaining spectral line data and Stokes I continuum data with high angular resolution (10"-40"), including a new HI dataset for the whole THOR survey region (l=14.0{deg}-67.4{deg} and |b|<=1.25{deg}). As we published the results of OH lines and continuum emission elsewhere, we concentrate on the HI analysis in this paper With the Karl G. Jansky Very Large Array (VLA) in C-configuration, we observed a large portion of the first Galactic quadrant, achieving an angular resolution of 40". At L Band, the WIDAR correlator at the VLA was set to cover the 21cm HI line, four OH transitions, a series of Hn{alpha} radio recombination lines (RRLs; n=151 to 186), and eight 128MHz-wide continuum spectral windows (SPWs), simultaneously. We publish all OH and RRL data from the C-configuration observations, and a new HI dataset combining VLA C+D+GBT (VLA D-configuration and GBT data are from the VLA Galactic Plane Survey) for the whole survey. The HI emission shows clear filamentary substructures at negative velocities with low velocity crowding. The emission at positive velocities is more smeared-out, likely due to higher spatial and velocity crowding of structures at the positive velocities. Compared to the spiral arm model of the Milky Way, the atomic gas follows the Sagittarius and Perseus Arm well, but with significant material in the inter-arm regions. With the C-configuration-only HI+continuum data, we produced a HI optical depth map of the THOR areal coverage from 228 absorption spectra with the nearest-neighbor method. With this map, we corrected the HI emission for optical depth, and the derived column density is 38% higher than the column density with optically thin assumption. The total HI mass with optical depth correction in the survey region is 4.7x10^8^M_{sun}_, 31% more than the mass derived assuming the emission is optically thin. If we applied this 31% correction to the whole Milky Way, the total atomic gas mass would be 9.4-10.5x10^9^M_{sun}_. Comparing the HI with existing CO data, we find a significant increase in the atomic-to-molecular gas ratio from the spiral arms to the inter-arm regions. The high-sensitivity and resolution THOR HI dataset provides an important new window on the physical and kinematic properties of gas in the inner Galaxy. Although the optical depth we derive is a lower limit, our study shows that the optical depth correction is significant for Hi column density and mass estimation. Together with the OH, RRL and continuum emission from the THOR survey, these new HI data provide the basis for high-angular-resolution studies of the interstellar medium (ISM) in different phases.
- ID:
- ivo://CDS.VizieR/J/A+A/619/A124
- Title:
- THOR survey in northern Galactic plane
- Short Name:
- J/A+A/619/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio continuum surveys of the Galactic plane can find and characterize HII regions, supernova remnants (SNRs), planetary nebulae (PNe), and extragalactic sources. A number of surveys at high angular resolution (<~25") at different wavelengths exist to study the interstellar medium (ISM), but no comparable high-resolution and high-sensitivity survey exists at long radio wavelengths around 21cm. Our goal is to investigate the 21cm radio continuum emission in the northern Galactic plane at <25" resolution. We observed a large fraction of the Galactic plane in the first quadrant of the Milky Way (l=14.0{deg}-67.4{deg} and |b|<=1.25{deg}) with the Karl G. Jansky Very Large Array (VLA) in the C-configuration covering six continuum spectral windows. These data provide a detailed view on the compact as well as extended radio emission of our Galaxy and thousands of extragalactic background sources. We used the BLOBCAT software and extracted 10916 sources. After removing spurious source detections caused by the sidelobes of the synthesised beam, we classified 10387 sources as reliable detections.We smoothed the images to a common resolution of 25" and extracted the peak flux density of each source in each spectral window (SPW) to determine the spectral indices {alpha} (assuming I(nu){prop.to}nu^alpha^). By cross-matching with catalogs of HII regions, SNRs, PNe, and pulsars, we found radio counterparts for 840 HII regions, 52 SNRs, 164 PNe, and 38 pulsars. We found 79 continuum sources that are associated with X-ray sources. We identified 699 ultrasteep spectral sources (alpha<-1.3) that could be high-redshift galaxies. Around 9000 of the sources we extracted are not classified specifically, but based on their spatial and spectral distribution, a large fraction of them is likely to be extragalactic background sources. More than 7750 sources do not have counterparts in the SIMBAD database, and more than 3760 sources do not have counterparts in the NED database. Studying the long wavelengths cm continuum emission and the associated spectral indices allows us to characterize a large fraction of Galactic and extragalactic radio sources in the area of the northern inner Milky Way. This database will be extremely useful for future studies of a diverse set of astrophysical objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/814/128
- Title:
- Timing noise & astrometry of Fermi-LAT pulsars
- Short Name:
- J/ApJ/814/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have constructed timing solutions for 81 {gamma}-ray pulsars covering more than five years of Fermi data. The sample includes 37 radio-quiet or radio-faint pulsars which cannot be timed with other telescopes. These timing solutions and the corresponding pulse times of arrival are prerequisites for further study, e.g., phase-resolved spectroscopy or searches for mode switches. Many {gamma}-ray pulsars are strongly affected by timing noise (TN), and we present a new method for characterizing the noise process and mitigating its effects on other facets of the timing model. We present an analysis of TN over the population using a new metric for characterizing its strength and spectral shape, namely, its time-domain correlation. The dependence of the strength on {nu} and {dot}{nu} is in good agreement with previous studies. We find that noise process power spectra S(f) for unrecycled pulsars are steep, with strong correlations over our entire data set and spectral indices s(f){propto}f^-{alpha}^ of {alpha}~5-9. One possible explanation for these results is the occurrence of unmodeled, episodic "microglitches". Finally, we show that our treatment of TN results in robust parameter estimation, and in particular we measure a precise timing position for each pulsar. We extensively validate our results with multi-wavelength astrometry, and using our updated position, we firmly identify the X-ray counterpart of PSR J1418-6058.
- ID:
- ivo://CDS.VizieR/J/A+A/653/A87
- Title:
- TOPGot sample, SEDs and CH3CN analysis
- Short Name:
- J/A+A/653/A87
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The TOPGot project targets a sample of 86 high-mass star-forming regions in different evolutionary stages from starless cores to ultra compact HII regions. The aim of the survey is to analyze different molecular species in a statistically significant sample to study the chemical evolution in high-mass star-forming regions, and identify chemical tracers of the different phases. In the first paper we present the sample and analyze the spectral energy distributions (SEDs) of the TOPGot sources to derive physical parameters. We also use the MADCUBA software to analyze the emission of methyl cyanide (CH_3_CN), a well-known tracer of high-mass star formation. The emission of the CH_3_CN(5K-4K) K-transitions has been detected towards 73 sources (85% of the sample). The emission of CH_3_CN has been detected towards all evolutionary stages, with the mean abundances showing a clear increase of an order of magnitude from high-mass starless-cores to later evolutionary stages. We found a conservative abundance upper limit for high-mass starless cores of X_CH_3_CN_<4.0x10^-11^, and a range in abundance of 4.0x10^-11^<X_CH_3_CN_<7.0x10^-11^ for those sources that are likely high-mass starless cores or very early high-mass protostellar objects. In fact, in this range of abundance we have identified five sources previously not classified as being in a very early evolutionary stage. The abundance of CH_3_CN can thus be used to identify high-mass star-forming regions in early phases of star-formation.
