We present results from a survey for gravitationally lensed radio lobes. Lensed lobes are a potentially richer source of information about galaxy mass distributions than lensed point sources, which have been the exclusive focus of other recent surveys. Our approach is to identify radio lobes in the Faint Images of the Radio Sky at Twenty cm (FIRST, Cat. <VIII/71>) catalog and then search optical catalogs for coincident foreground galaxies, which are candidate lensing galaxies. We then obtain higher resolution images of these targets at both optical and radio wavelengths and obtain optical spectra for the most promising candidates. We present maps of several radio lobes that are nearly coincident with galaxies. We have not found any new and unambiguous cases of gravitational lensing. One radio lobe in particular, FOV J0743+1553, has two hot spots that could be multiple images produced by a z=0.19 spiral galaxy, but the lensing interpretation is problematic.
The results of observations of a complete sample of flat-spectrum radio sources with spectral indices {alpha}>-0.5 are presented. The sample was selected from the Zelenchuk Survey at 3.9GHz (See Cat. <VIII/49>) and contains all sources with declinations 4-6 degrees, galactic latitudes |b|>10 degrees, and 3.9-GHz fluxes >200mJy. Spectra at 0.97-21.7 GHz were obtained for all 69 sample sources. The spectra were classified and a correlation between variability amplitude and spectrum shape was found.
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.
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.
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>
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.
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.
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.
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.
