- ID:
- ivo://CDS.VizieR/J/MNRAS/227/607
- Title:
- Optical identifications of Molonglo sources
- Short Name:
- J/MNRAS/227/607
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical identifications have been sought for 304 radio sources from the declination -20{deg} region of the first Molonglo deep survey. Optical objects have been measured using the Palomar sky survey to an accuracy of 1 arcsec and magnitude estimates are to 0.4mag. Finding charts are given for all fields with optical objects within +/-2{sigma} of the radio position. Sixteen QSOs have been confirmed (details have been reported elsewhere) amongst the blue stellar-like objects and spectroscopy is complete to m_o_=19.5. The mean magnitude of the QSOs is 19.2 and the mean redshift is 1.34. A study of the background densities of objects indicates that about half of the remaining blue stellar-like objects are QSOs and about 80 per cent of the galaxies are associated with the radio emission. The QSOs are amongst the fainter and the bluer of the blue stellar-like objects. There is no evidence for any average offset between the radio and optical positions.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/115/11
- Title:
- Optical identifications of radio sources
- Short Name:
- J/A+AS/115/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD images of the fields of 115 radio sources from the 1Jy, S4 and S5 catalogues are presented. New optical counterparts have been found for a total of 34 sources, a large fraction of which had as yet only been described as empty fields on Sky Survey Plates. Of the 54 radio sources with previously published identifications, 50 optical counterparts have been confirmed while for 4 sources new identifications are proposed. R band magnitudes, derived from the CCD images, are provided for all but a few identified optical counterparts. The fields at the positions of 27 radio sources are still empty down to a limiting magnitude of at least m_R_=22mag, requiring much deeper optical as well as additional infrared images for establishing their optical counterparts.
- ID:
- ivo://CDS.VizieR/J/A+AS/105/211
- Title:
- Optical identification status of 1Jy catalogue
- Short Name:
- J/A+AS/105/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/PAZh/34/920
- Title:
- Optical ident. of 230 HIPASS radio sources
- Short Name:
- J/PAZh/34/920
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the coordinates, apparent magnitudes, and morphological types for 230 galaxies presumably identified with HIPASS (HI Parkes All-Sky Survey) sources. The new optical counterparts of the HIPASS sources follow the well-known statistical relationships between the hydrogen mass, luminosity, and type of galaxies. Low-surface-brightness galaxies constitute a significant fraction among these objects. The median value of the hydrogen mass-to-luminosity ratio for them is a factor of 2 or 3 higher than that for bright HIPASS galaxies, reaching 1.7M_{sun}_/L_{sun}_. A number of our objects are located near the boundary log (M(HI)/L(B))=0.2(M(B)+20) that defines the zone of gravitational stability of disk galaxies against large-scale star formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/329/700
- Title:
- Optical IDs of JVAS using APM
- Short Name:
- J/MNRAS/329/700
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Files list1, list2, and list3 contain the lists of flat spectrum radio sources with their optical identifications from the APM (Automated Plate Measurement Facility at Cambridge) catalogue. List1 corresponds to the sources which are part of both the complete JVAS++ (a new complete sample constructed with selection criteria similar to those of JVAS -- Jodrell Bank VLA Astrometric Survey: S_5GHz_>200mJy, {alpha}_1.4-5GHz_>-0.5), and with the use of the more accurate GB6 and NVSS surveys) and original JVAS sample, List2 corresponds to sources which are only part of JVAS++, and List3 to sources which are only part of JVAS. The combination of List1 and List2 is a complete sample with S_6cm_>200mJy.
- ID:
- ivo://CDS.VizieR/J/AJ/142/105
- Title:
- Optically Bright Extragalactic Radio Sources
- Short Name:
- J/AJ/142/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is expected that the European Space Agency mission Gaia will make possible to determine coordinates in the optical domain of more than 500,000 quasars. In 2006, a radio astrometry project was launched with the overall goal to make comparison of coordinate systems derived from future space-born astrometry instruments with the coordinate system constructed from analysis of the global very long baseline interferometry (VLBI) more robust. Investigation of their rotation, zonal errors, and the non-alignment of the radio and optical positions caused by both radio and optical structures are important for validation of both techniques. In order to support these studies, the densification of the list of compact extragalactic objects that are bright in both radio and optical ranges is desirable. A set of 105 objects from the list of 398 compact extragalactic radio sources with declinations >-10{deg} was observed with the VLBA+EVN with the primary goal of producing their images with milliarcsecond resolution. These sources are brighter than 18 magnitude at V band, and they were previously detected at the European VLBI network. In this paper coordinates of observed sources have been derived with milliarcsecond accuracies from analysis of these VLBI observations following the method of absolute astrometry. The catalog of positions of 105 target sources is presented. The accuracies of sources coordinates are in the range of 0.3 to 7mas, with the median 1.1mas.
- ID:
- ivo://CDS.VizieR/J/AJ/146/5
- Title:
- Optically Bright extragalactic Radio Sources II
- Short Name:
- J/AJ/146/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Future space-borne astrometry missions, such as Gaia, will be able to determine the optical positions of hundreds of quasars with submilliarcsecond accuracies comparable to those achieved in radio by very long baseline interferometry (VLBI). Comparisons of coordinate systems from space-borne missions and VLBI will be very important, first for investigations of possible systematic errors and second for investigations of possible shifts between centroids of radio and optical emissions in active galactic nuclei. In order to make such a comparison more robust, a program for densification of the grid of radio sources detectable with both VLBI and Gaia was launched in 2006. Program sources are 398 quasars with declinations >-10{deg} that are brighter than 18mag at the V band. The first two observing campaigns were run in 2007-2008. In the third campaign, a set of 291 objects from that list was observed with the VLBA+EVN in 2010-2011 with the primary goal of producing their images with milliarcsecond resolution. In this paper, following the method of absolute astrometry, coordinates of observed sources have been derived with milliarcsecond accuracies from analysis of these observations. The catalog of positions of 295 target sources, estimates of their correlated flux densities at 2.2 and 8.4GHz, and their images are presented. The accuracies of source coordinates are in a range of 2-200mas, with a median of 3.2mas.
- ID:
- ivo://CDS.VizieR/J/A+A/463/97
- Title:
- Optical observations of GPS radio sources
- Short Name:
- J/A+A/463/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify optical counterparts, address uncertain identifications and measure previously unknown redshifts of the host galaxies of candidate Gigahertz Peaked Spectrum (GPS) radio sources, and study their stellar populations. Long slit spectroscopy and deep optical imaging in the B, V and R bands, were obtained with the Very Large Telescope.
- ID:
- ivo://CDS.VizieR/J/A+AS/117/335
- Title:
- Optical positions of radio emitting stars
- Short Name:
- J/A+AS/117/335
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to contribute to the alignment of the radio and optical reference frames, 50 stars with confirmed radio emission and published radio positions were observed by astrographical means. Additionally, two confirmed radio-stars of fainter magnitude were observed using a CCD direct camera with a long focus, large aperture telescope. The reductions are made relative to four catalogues: the Carlsberg Meridian Catalogue #4, the International Reference Stars Catalogue, the Positions and Proper Motion Catalogue and the Astrographical Catalogue of Reference Stars. The best results were obtained with the CAMC catalogue. The plate error of a radio star position is 0.07" for both right ascension and declination, rising to 0.10"-0.20" for bright stars. Ten of the program stars are not in the HIPPARCOS Input Catalogue and 12 do not belong to any of the major reference catalogues used. As soon as the HIPPARCOS results become available, its reference stars already measured in the plates will enable us to get positions for those 10 radio stars in the HIPPARCOS system.
- ID:
- ivo://CDS.VizieR/J/A+AS/89/311
- Title:
- Optical positions of 221 radio stars
- Short Name:
- J/A+AS/89/311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains optical positions of 221 radio stars observed with the Bordeaux automatic meridian circle. The observations were strictly differential, a convenient number of FK5 stars being used each night to calculate the instrumental parameters. The mean positions were corrected for chromatic refraction and also for photocenter effect in the case of duplicity. The asymptotic accuracy is expected to be about 0.05" for the Northern stars with a number of observations greater than 25. Some positions have been published previously, and the improved positions given here supersede earlier published data.
