- 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 Note: this catalogue is superseded by Cat.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>
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- 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).
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/377/801
- Title:
- Fourth list of the Karachentsev catalog
- Short Name:
- J/A+A/377/801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents HI observations of 165 dwarf galaxy candidates from the Karachentsev catalog of candidates for nearby dwarf galaxies prepared from film copies of POSSII and the ESO/SERC southern extension. Now a total of 601 galaxies from the published Karachentsev catalog have been searched for HI emission. Table 1 lists coordinates and general optical properties while Table 2 presents HI data and some global properties of these galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1872
- Title:
- Fourth VLBA calibrator survey: VCS4
- Short Name:
- J/AJ/131/1872
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the fourth extension to the VLBA Calibrator Survey, containing 258 new sources not previously observed with very long baseline interferometry (VLBI). This survey, based on three 24hr Very Long Baseline Array observing sessions, fills remaining areas on the sky above declination -40{deg} where the calibrator density is less than one source within a 4{deg} radius disk in any given direction. The share of these areas was reduced from 4.6% to 1.9%. Source positions were derived from astrometric analysis of group delays determined at 2.3 and 8.6GHz frequency bands using the Calc/Solve software package. The VCS4 catalog of source positions, plots of correlated flux density versus projected baseline length, contour plots, and fits files of naturally weighted CLEAN images, as well as calibrated visibility function files, are available online at http://vlbi.gsfc.nasa.gov/vcs4 .
