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521. Flat-spectrum radio sources long-term variability
ID:
ivo://CDS.VizieR/J/AZh/89/388
Title:
Flat-spectrum radio sources long-term variability
Short Name:
J/AZh/89/388
Date:
21 Oct 2021
Publisher:
CDS
Description:
The paper reports the results of ten-year centimeter-wavelength observations with the RATAN-600 radio telescope of a complete sample of 83 flat-spectrum sources from the GB6 catalog of the MGB Survey (Cat. VIII/40), with S_4.85_>200mJy at declinations 10{deg}-12{deg}30'. Starting in 2000, the observations were conducted simultaneously at six frequencies in the range 0.97-21.7GHz. Seventy-six sources (including 54 quasars) have been identified with optical objects, which have redshifts in the range z=0.331-3.601.
522. Flat-spectrum symmetric radio sources
ID:
ivo://CDS.VizieR/J/MNRAS/368/1411
Title:
Flat-spectrum symmetric radio sources
Short Name:
J/MNRAS/368/1411
Date:
21 Oct 2021
Publisher:
CDS
Description:
The radio sources listed below were selected from the Jodrell-VLA Astrometric Survey and the Cosmic-Lens All-Sky Survey (part 1) and constitute a (non-complete) parent sample for the selection of flat-spectrum symmetric object candidates (the ones which show structure, when their VLA-A 8.4GHz data are analysed). The parent sample contains northern hemisphere objects with 8.4GHz flux densities greater than 100mJy, galactic latitudes greater than 10 degrees and 1.40-to-4.85GHz spectral indices (when known; if not, the source is kept in the sample) smaller than 0.50 (flat). The most relevant properties of the parent sample are listed in the Table.
523. Flux densities at 22.25 MHz. I.
ID:
ivo://CDS.VizieR/J/AJ/74/366
Title:
Flux densities at 22.25 MHz. I.
Short Name:
J/AJ/74/366
Date:
21 Oct 2021
Publisher:
CDS
Description:
Flux densities for 200 radio sources have been derived from observations with the 22.25MHz radio telescope at the Dominion Radio Astrophysical Observatory. Ionospheric conditions, the method of calibration, and the reduction procedure are described. The effects of these new measures on the spectral indices of the sources are indicated. Note: this catalogue is superseded by Cat. <J/A+AS/65/485>
524. Flux densities for 290 blazars
ID:
ivo://CDS.VizieR/J/AN/338/700
Title:
Flux densities for 290 blazars
Short Name:
J/AN/338/700
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of nine years of the blazar observing programme at the RATAN-600 radio telescope (2005-2014). The data were obtained at six frequency bands (1.1, 2.3, 4.8, 7.7, 11.2, 21.7GHz) for 290 blazars, mostly BL Lacs. In addition, we used data at 37GHz obtained quasi-simultaneously with the Metsahovi radio observatory for some sources. For each source NVSS name (RA (hhmmss) and DEC (ddmmss) for the J2000.0 epoch), and flux densities at seven frequencies are presented (1.1-37GHz).
525. Flux densities of 235 pulsars at 102.5MHz
ID:
ivo://CDS.VizieR/J/AZh/77/499
Title:
Flux densities of 235 pulsars at 102.5MHz
Short Name:
J/AZh/77/499
Date:
21 Oct 2021
Publisher:
CDS
Description:
The flux densities of 235 mostly faint pulsars at 102.5MHz are presented. The observations were carried out on the very sensitive Large Phased Array of the Lebedev Institute of Physics in 1994-1998. The procedure used for the observations and data processing is described in detail, and estimates of probable errors, including the effect of interstellar scintillations, are given. The mean spectral indices at 102-408MHz for normal and millisecond pulsars are calculated and compared with information from higher frequency data. There is a deficit of pulsars at distances of less than 3 kpc.
526. Flux-density-complete sample of radio sources
ID:
ivo://CDS.VizieR/J/AZh/83/241
Title:
Flux-density-complete sample of radio sources
Short Name:
J/AZh/83/241
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of observations of flux-density- complete sample of radio with the RATAN-600 radio telescope at 0.97, 2.3, 3.9, 7.7, 11.1, and 21.7GHz. The sample was extracted from the GB6 catalog (<VIII/40>) at 4.85GHz, and contains all the sources at declination zone 74-75{deg} (J2000) with flux densities S(4.85)>100mJy. We have obtained optical identifications for 67% of radio sources with flat spectra and 36% of those with normal spectra.
527. Fluxes of Faint Radio Sources at 2.7/4.75 GHz
ID:
ivo://CDS.VizieR/VIII/57
Title:
Fluxes of Faint Radio Sources at 2.7/4.75 GHz
Short Name:
VIII/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
This table is a compilation of revised 4.75 GHz and 2.695 GHz flux densities and corresponding spectral indices at epoch 1986.2 of a catalog of 239 sources, which has previously been published by Forkert and Altschuler, (1987A&AS...70...77F). It comprises 209 sources (marked 'A'), forming a complete, flux density limited sample above 50 mJy at 4.76 GHz in 1981.9 (Altschuler, 1986A&AS...65..267A), and 30 sources (marked 'a') below this limit, but with 5.0 GHz flux densities from 1971.0 (Davis, 1971AJ.....76..980D). The catalogue covers a narrow strip of the sky around declination of 33 degrees. The flux densities were calibrated with 3C286 on the scale of Kellermann, Pauliny-Toth and Williams (1969ApJ...157....1K). After publication of the catalog a statistical analysis for flux density variability in the data has been performed (Forkert, 1990), using 6cm flux density measurements of Davis (1971AJ.....76..980D) and Altschuler (1986A&AS...65..267A) and the 2.695 GHz flux densities of Pauliny-Toth et al. (1974A&A....35..421P), the details and results of which are going to be published elsewhere (Altschuler & Forkert, in preparation). For the purposes of this analysis it has become necessary to obtain more individual error estimates of the 1986.2 data, not dominated by the effect of overall scale errors. This revision for some of the sources also led to slightly different flux densities from those previously published. The variability study proved the flux density errors to represent the individual 1-sigma uncertainties, WITHOUT the effect of overall scale errors. From the aforementioned comparison with other measurements scale errors of ~1% at 2.695 GHz and ~3% at 4.75 GHz seem likely.
528. Formaldehyde maser flares in IRAS 18566+0408
ID:
ivo://CDS.VizieR/J/ApJ/717/L133
Title:
Formaldehyde maser flares in IRAS 18566+0408
Short Name:
J/ApJ/717/L133
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report results of an extensive observational campaign of the 6cm formaldehyde maser in the young massive stellar object IRAS 18566+0408 (G37.55+0.20) conducted from 2002 to 2009. Using the Arecibo Telescope, the Very Large Array, and the Green Bank Telescope, we discovered quasi-periodic formaldehyde flares (P~237 days). Based on Arecibo observations, we also discovered correlated variability between formaldehyde (H_2_CO) and methanol (CH_3_OH) masers. The H_2_CO and CH_3_OH masers are not spatially coincident, as demonstrated by different line velocities and high angular resolution MERLIN observations. The flares could be caused by variations in the infrared radiation field, possibly modulated by periodic accretion onto a young binary system.
529. Fourth Cambridge Survey (4C)
ID:
ivo://CDS.VizieR/VIII/4
Title:
Fourth Cambridge Survey (4C)
Short Name:
VIII/4
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Fourth Cambridge Radio Survey (4C) Catalogue contains all survey data from the papers of Pilkington and Scott (1965MmRAS..69..183P) and Gower, Scott and Wills (1967MmRAS..71...49G). These data result from a survey of radio sources between declinations -07 and +80 degrees using the large Cambridge interferometer at 178 MHz. The computerized catalog contains for each source the 4C number, 1950 position, measured flux density, accuracy class, galactic coordinates, and remarks. For some sources miscellaneous brief comments such as cross identifications to the 3C catalog or remarks on contamination from nearby sources are given at the ends of the data records. A flag (*) is included if there are additional remarks in the published catalog.
530. Fourth catalog of Fermi LAT-detected AGNs (4LAC)
ID:
ivo://CDS.VizieR/J/ApJ/892/105
Title:
Fourth catalog of Fermi LAT-detected AGNs (4LAC)
Short Name:
J/ApJ/892/105
Date:
17 Jan 2022 00:31:09
Publisher:
CDS
Description:
The fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between 2008 August 4 and 2016 August 2 contains 2863 objects located at high Galactic latitudes (|b|>10{deg}). It includes 85% more sources than the previous 3LAC catalog based on 4yr of data. AGNs represent at least 79% of the high-latitude sources in the fourth Fermi-Large Area Telescope Source Catalog (4FGL), which covers the energy range from 50MeV to 1TeV. In addition, 344 gamma-ray AGNs are found at low Galactic latitudes. Most of the 4LAC AGNs are blazars (98%), while the remainder are other types of AGNs. The blazar population consists of 24% Flat Spectrum Radio Quasars (FSRQs), 38% BL Lac-type objects, and 38% blazar candidates of unknown types (BCUs). On average, FSRQs display softer spectra and stronger variability in the gamma-ray band than BL Lacs do, confirming previous findings. All AGNs detected by ground-based atmospheric Cerenkov telescopes are also found in the 4LAC.