- ID:
- ivo://CDS.VizieR/VIII/59
- Title:
- the FIRST Survey, version 1999Jul
- Short Name:
- VIII/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The FIRST survey to produce Faint Images of the Radio Sky at Twenty centimeters began in 1993. It uses the VLA (Very Large Array, a facility of the National Radio Observatory (NRAO)) at a frequency of 1.4GHz, and it is slated to 10,000 deg^2^ to a sensitivity of about 1mJy with an angular resolution of about 5". The co-added images are available on the Internet (see the FIRST home page at http://sundog.stsci.edu/ for details). The source catalogue is derived from the images. This version of the FIRST Survey is derived from the 1993 through 1998 observations, and contains 549,707 sources covering the north and south Galactic caps. The catalog covers about a total of 6060 square degrees of sky (5450 square degrees in the north and 610 square degrees in the south). No new data were taken for the south Galactic cap from the preceding version (catalog <VIII/51>), but the southern images south of about -2 degrees were reprocessed with an improved pipeline script that substantially reduces the sidelobe levels in a small fraction of the fields. Consequently, many of the southern sources have slight changes in their positions, flux densities, and other properties; a small number of sources from the previous catalog are missing from this catalog.
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Search Results
- ID:
- ivo://CDS.VizieR/VIII/105
- Title:
- The GLEAM 4-Jy (G4Jy) Sample
- Short Name:
- VIII/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Murchison Widefield Array (MWA) has observed the entire southern sky (Declination, {delta}<30{deg}) at low radio-frequencies, over the range 72-231MHz. These observations constitute the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey, and we use the extragalactic catalogue (Galactic latitude, |b|>10{deg}) to define the GLEAM 4-Jy (G4Jy) Sample. This is a complete sample of the 'brightest' radio-sources (S_151MHz_>4Jy), the majority of which are active galactic nuclei with powerful radio-jets. Crucially, low-frequency observations allow the selection of such sources in an orientation-independent way (i.e. minimising the bias caused by Doppler boosting, inherent in high-frequency surveys). We then use higher-resolution radio images, and information at other wavelengths, to morphologically classify the brightest components in GLEAM. We also conduct cross-checks against the literature, and perform internal matching, in order to improve sample completeness (which is estimated to be >95.5%). This results in a catalogue of 1,863 sources, making the G4Jy Sample over 10 times larger than that of the revised Third Cambridge Catalogue of Radio Sources (3CRR; S_178MHz_>10.9Jy). Of these G4Jy sources, 78 are resolved by the MWA (Phase-I) synthesised beam (~2' at 200MHz), and we label 67% of the sample as 'single', 26% as 'double', 4% as 'triple', and 3% as having 'complex' morphology at ~1GHz (45" resolution). We characterise the spectral behaviour of these objects in the radio, and find that the median spectral-index is {alpha}=-0.740+/-0.012 between 151MHz and 843MHz, and {alpha}=-0.786+/-0.006 between 151MHz and 1400MHz (assuming a power-law description, S_{nu}_{prop.to}{nu}^{alpha}^), compared to {alpha}=-0.829+/-0.006 within the GLEAM band. Alongside this, our value-added catalogue provides mid-infrared source associations (subject to 6" resolution at 3.4um) for the radio emission, as identified through visual inspection and thorough checks against the literature. As such, the G4Jy Sample can be used as a reliable training set for cross-identification via machine-learning algorithms. We also estimate the angular size of the sources, based on their associated components at ~1GHz, and perform a flux-density comparison for 67 G4Jy sources that overlap with 3CRR. Analysis of multi-wavelength data, and spectral curvature between 72MHz and 20GHz, will be presented in subsequent papers, and details for accessing all G4Jy overlays are provided at https://github.com/svw26/G4Jy.
- ID:
- ivo://CDS.VizieR/VIII/53
- Title:
- The Green Bank Survey
- Short Name:
- VIII/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog presents the parts I, II, and III of the Green Bank survey of extragalactic radio sources at 1400 MHz. The data were obtained with the 300' antenna, producing a beamwidth of 10'x11' FWHM. Part I of the survey covers about 521 square degrees of the sky with RA from 7h17m to 16h23m, DEC from +45.8{deg} to +51.7{deg}. 1086 sources are presented down to a limiting flux density of 90 mJy. These data were originally published in Maslowski, 1972, Acta Astronomica, 22, 227 (1972AcA....22..227M). Part II of the survey covers 0.28 sr of the sky with RA from 7h08m to 16h57m, DEC from +31.9{deg} to +39.7{deg}. 2022 sources are presented down to a limiting flux density of 0.09 mJy. Spectral indices between 1400 MHz and 408 MHz are determined for most sources by comparison with the B2 source catalog (Cat.<VIII/36>). These data were originally published in Machalski 1978, Acta Astronomica, 28, 367 (1978AcA....28..367M) Part III of the survey covers an area of 0.099 sr at declinations between 70 and 76.8 degrees. This catalog contains a total of 676 radio sources, of which 502 are statistically complete to 112 mJy. These data were originally published as Rys and Machalski, 1987, Acta Astronomica, 37, 163 (1987AcA....37..163R).
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/196
- Title:
- The invisible AGN catalogue
- Short Name:
- J/MNRAS/468/196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large fraction of active galactic nuclei (AGN) are 'invisible' in extant optical surveys due to either distance or dust-obscuration. The existence of this large population of dust-obscured, infrared (IR)-bright AGN is predicted by models of galaxy-supermassive black hole coevolution and is required to explain the observed X-ray and IR backgrounds. Recently, IR colour cuts with Wide-field Infrared Survey Explorer have identified a portion of this missing population. However, as the host galaxy brightness relative to that of the AGN increases, it becomes increasingly difficult to differentiate between IR emission originating from the AGN and from its host galaxy. As a solution, we have developed a new method to select obscured AGN using their 20-cm continuum emission to identify the objects as AGN. We created the resulting invisible AGN catalogue by selecting objects that are detected in AllWISE (mid-IR) and FIRST (20 cm), but are not detected in SDSS (optical) or 2MASS (near-IR), producing a final catalogue of 46 258 objects. 30 per cent of the objects are selected by existing selection methods, while the remaining 70 per cent represent a potential previously unidentified population of candidate AGN that are missed by mid-IR colour cuts. Additionally, by relying on a radio continuum detection, this technique is efficient at detecting radio-loud AGN at z>=0.29, regardless of their level of dust obscuration or their host galaxy's relative brightness.
- ID:
- ivo://CDS.VizieR/J/ApJ/854/124
- Title:
- The Megamaser Cosmology Project. X.
- Short Name:
- J/ApJ/854/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution (submas) Very Long Baseline Interferometry maps of nuclear H_2_O megamasers for seven galaxies. In UGC 6093, the well-aligned systemic masers and high-velocity masers originate in an edge-on, flat disk and we determine the mass of the central supermassive black holes (SMBH) to be M_SMBH_=2.58x10^7^M_{sun}_ (+/-7%). For J1346+5228, the distribution of masers is consistent with a disk, but the faint high-velocity masers are only marginally detected, and we constrain the mass of the SMBH to be in the range (1.5-2.0)x10^7^M_{sun}_. The origin of the masers in Mrk 1210 is less clear, as the systemic and high-velocity masers are misaligned and show a disorganized velocity structure. We present one possible model in which the masers originate in a tilted, warped disk, but we do not rule out the possibility of other explanations including outflow masers. In NGC 6926, we detect a set of redshifted masers, clustered within a parsec of each other, and a single blueshifted maser about 4.4pc away, an offset that would be unusually large for a maser disk system. Nevertheless, if it is a disk system, we estimate the enclosed mass to be M_SMBH_<4.8x10^7^M_{sun}_. For NGC 5793, we detect redshifted masers spaced about 1.4pc from a clustered set of blueshifted features. The orientation of the structure supports a disk scenario as suggested by Hagiwara+ (2001ApJ...560..119H). We estimate the enclosed mass to be M_SMBH_<1.3x10^7^M_{sun}_. For NGC 2824 and J0350-0127, the masers may be associated with parsec- or subparsec-scale jets or outflows.
936. The MERLIN Archive
- ID:
- ivo://CDS.VizieR/B/merlin
- Title:
- The MERLIN Archive
- Short Name:
- B/merlin
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This database contains a log of MERLIN archive data since 1992 which have been partially reduced and are electronically available. It is managed and updated by the MERLIN staff. All data are taken using a single IF and correlated using 2-bit digitisation.
- ID:
- ivo://CDS.VizieR/VIII/52B
- Title:
- The MIT-Green Bank 5GHz Survey
- Short Name:
- VIII/52B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The MIT-Green Bank 5GHz survey catalog was produced from four separate surveys with the National Radio Astronomy Observatory (NRAO) 91m transit telescope (Bennett et al., 1986ApJS...61....1B (MG1); Langston et al., 1990ApJS...72..621L (MG2); Griffith et al., 1990ApJS...74..129G (MG3); Griffith et al. 1991ApJS...75..801G (MG4)). The sky coverage of the various surveys is: 00h < RAB < 24h, -00d30'13" < DECB < +19d29'47" for MG1; 04h < RAJ < 21h, +17.0d < DECJ < +39d09' for MG2; 16h30m < RAB < 05h, +17d < DECB < +39d09' for MG3; and 15h30m < RAB < 02h30m, +37.00d < DECB < +50d58'48" for MG4; where RAB and DECB refer to B1950 coordinates, and RAJ and DECJ refer to J2000 coordinates. The catalog contains 20344 sources detected with a signal-to-noise ratio greater than 5 and 3836 possible detections (MG1) with a signal-to-noise ratio less than 5. Spectral indices are computed for MG1 sources also identified in the Texas 365MHz survey (Douglas et al. 1980), and for MG1-MG4 sources also identified in the NRAO 1400MHz Survey (Condon and Broderick 1985).
- ID:
- ivo://CDS.VizieR/J/A+AS/99/545
- Title:
- The Miyun 232 MHz survey. I
- Short Name:
- J/A+AS/99/545
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains a new meter-wave survey of the sky region north of declination 30{deg}, carried out with the Miyun 232 MHz SSSynthesis Radio Telescope (MSRT) at HPBW 3.8' x 3.8' cosec(dec). Results from two fields are presented here; the fields are 8 degrees on a side, centered at 0041+41.2 and 0700+35.0. The accuracy of flux determination is limited by background fluctuation which is about 30 mJy. The catalogue is complete for sources with flux greater than 0.25 Jy. The total number of sources listed in the catalogue is 687.
939. The mJIVE-20 catalog
- ID:
- ivo://CDS.VizieR/J/AJ/147/14
- Title:
- The mJIVE-20 catalog
- Short Name:
- J/AJ/147/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the description and early results of the mJy Imaging VLBA Exploration at 20cm (mJIVE-20). mJIVE-20 is a large project on the Very Long Baseline Array which is systematically inspecting a large sample of mJy radio sources, pre-selected from the Faint Images of the Radio Sky at Twenty cm (FIRST) survey made with the Very Large Array, to identify any compact emission that may be present. The survey is being undertaken using filler time on the VLBA, which utilizes short segments scheduled in bad weather and/or with a reduced number of antennas, during which no highly rated science projects can be scheduled. The newly available multifield capability of the VLBA makes it possible for us to inspect of the order of 100 sources per hour of observing time with a 6.75{sigma} detection sensitivity of approximately 1mJy/beam. The results of the mJIVE-20 survey are made publicly available as soon as the data are calibrated. After 18 months of observing, over 20000 FIRST sources have been inspected, with 4336 very long baseline interferometry detections. These initial results suggest that within the range 1-200mJy, fainter sources are somewhat more likely to be dominated by a very compact component than brighter sources. Over half of all arcsecond-scale mJy radio sources contain a compact component, although the fraction of sources that are dominated by milliarcsecond scale structure (where the majority of the arcsecond scale flux is recovered in the mJIVE-20 image) is smaller at around 30%-35%, increasing toward lower flux densities. Significant differences are seen depending on the optical classification of the source. Radio sources with a stellar/point-like counterpart in the Sloan Digital Sky Survey (SDSS) are more likely to be detected overall, but this detection likelihood appears to be independent of the arcsecond-scale radio flux density. The trend toward higher radio compactness for fainter sources is confined to sources that are not detected in SDSS or that have counterparts classified as galaxies. These results are consistent with a unification model of active galactic nuclei in which less luminous sources have on average slower radio jets, with lower Doppler suppression of compact core emission over a wider range of viewing angles.
940. The MORX catalogue
- ID:
- ivo://CDS.VizieR/V/148
- Title:
- The MORX catalogue
- Short Name:
- V/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This automated catalogue combines all the largest published optical, radio and X-ray sky catalogues to find probable radio/X-ray associations to optical objects, plus double radio lobes, using uniform processing against all input data. The total count is 1002855 optical objects so presented. Each object is displayed with J2000 astrometry, optical and radio/X-ray identifiers, red and blue photometry, and calculated probabilities and optical field solutions of the associations. This is the third and final edition of this method.
