- ID:
- ivo://CDS.VizieR/J/ApJS/75/801
- Title:
- MGIV (Fourth MIT-Green Bank) 5GHz Survey
- Short Name:
- J/ApJS/75/801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The MIT-Green Bank IV (MG IV) 5 GHz survey covers 0.504 sr of sky in the right ascension range 15.5 to 2.5 hours, between +37.00 and +50.98 degrees declination (B1950). The final MG IV catalog contains 3427 sources detected with a signal-to-noise ratio greater than 5. The catalog was produced from two separate north and south surveys with the National Radio Astronomy Observatory (NRAO) 91m transit telescope. The north survey was produced from data collected while scanning the telescope north from +39.0 to +50.98 degrees declination and the south survey from data collected from scans from +48.98 to +37.00 degrees declination. The completeness and reliability of the final source list is checked by examination of north and south source lists in a twice observed comparison region, lying between +39.15 and +48.83 degrees declination and excluding the area between +/-10 degrees Galactic latitude. The comparison region covers 0.270 sr of sky and contains 1094 sources. In this region, the MG IV catalog contains 423 sources brighter than 90 mJy and is shown to be 99.1 +/- 1.2% complete at this flux density level. Spectral indices are computed for sources identified in the NRAO 1400 MHz Survey (published by Condon and Broderick in 1985). A comparison of the spectral index distributions between +/- 10 and outside of +/- 10 degrees Galactic latitude is presented.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/134/1488
- Title:
- MG1 Variable Star Catalog (MG1-VSC)
- Short Name:
- J/AJ/134/1488
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the first MOTESS-GNAT variable-star survey, a deep, wide-field variability survey conducted over 2yr with a total sky coverage of 300deg^2^. In this survey, we identified 26042 variable-star candidates with magnitudes R=13-19, including 5271 that are periodic at the 99% confidence level. We recovered 59 out of 68 members of the General Catalogue of Variable Stars (GCVS) that are in this brightness range. We discuss the implications for completeness and accuracy for both this survey and the GCVS; the implied completeness for distinctly classifiable variable stars in our survey is ~85%-90%. We also discuss some of the caveats of our survey results. We conclude that this instrument design is ideal for an inexpensive, longitudinally distributed telescope network that could be used to study faint or rare transient phenomena in a previously unexplored regime of parameter space.
- ID:
- ivo://CDS.VizieR/J/MNRAS/402/2792
- Title:
- 1388MHz ATLBS Low-Brightness Survey
- Short Name:
- J/MNRAS/402/2792
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a radio survey carried out with the Australia Telescope Compact Array. A motivation for the survey was to make a complete inventory of the diffuse emission components as a step towards a study of the cosmic evolution in radio source structure and the contribution from radio-mode feedback on galaxy evolution. The Australia Telescope Low-Brightness Survey (ATLBS) at 1388MHz covers 8.42deg^2^ of the sky in an observing mode designed to yield images with exceptional surface brightness sensitivity and low confusion. The survey was carried out in two adjacent regions on the sky centred at 00:35:00-67:00:00 and 00:59:17=-67:00:00 (J2000.0). The ATLBS radio images, made with 0.08mJy/beam rms noise and 50arcsec beam, detect a total of 1094 sources with peak flux exceeding 0.4mJy/beam. The ATLBS source counts were corrected for blending, noise bias, resolution and primary beam attenuation; the normalized differential source counts are consistent with no upturn down to 0.6mJy.
- ID:
- ivo://CDS.VizieR/J/A+AS/58/1
- Title:
- 1412 MHz catalogue of Westerbork survey. I.
- Short Name:
- J/A+AS/58/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A radio survey has been conducted with the Westerbork Synthesis Radio Telescope for nine fields in four high latitude areas for which deep, multicolor Kitt Peak 4-m plates are available. A total of 471 sources are tabulated; 306 of these form a well defined, complete sample. The influence of the selection criteria on sample completeness is discussed. Angular size distribution has been precisely derived, in virtue of the 3 km resolution obtainable with the present instrument, and a smaller fraction of sources larger than about 20arcsec is noted for the 1-10mJy range than for the 10-100mJy. The 1412MHz source counts are consistent at different cutoff levels, showing that the statistical corrections for population and resolution bias are reliable. The present counts are consistent with previous 1.4GHz counts, which are here given for the 1-100000mJy flux range.
- ID:
- ivo://CDS.VizieR/J/A+AS/58/39
- Title:
- 1412 MHz catalogue of Westerbork survey. II
- Short Name:
- J/A+AS/58/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A deep multicolor optical identification program is presented for a complete sample of 302 radio sources that were observed with the Westerbork Synthesis Radio Telescope within 5.52{deg}^2^ down to S_1.4GHz_>~0.6mJy (5{sigma}). Optical identifications are made from multicolor prime focus plates taken with the Kitt Peak 4 meter telescope in the passbands U,J,F and N with approximate respective limiting magnitudes of ~23.3, 23.7, 22.7 and 21.1. The astrometry has systematic errors smaller than 0.2"-0.3", while the random errors are of order 0.4". The agreement between the radio and optical coordinate frames is on average better than 0.25". Identifications are based on positional coincidence using the likelihood ratio method. For 171 out of the 302 radio sources likely identifications are proposed with an a posteriori identification percentage of 53%, 14 expected spurious objects (or 5% of all radio sources), while not more than 4 identifications have been missed. The sample reliability is 92% and its completeness 98%. About 20% of the identifications are stellar objects, the remaining have extended images or are too faint to be classified. About 15% of the identifications appear in possible clusters. The identification statistics are roughly constant from field to field, except for the Hercules 2 field which has an unusually high identification fraction (74%). The identification fraction is presented as a function of 21 cm flux density and limiting magnitude, and amounts to 15% for 1<~S_1.4GHz_<~100mJy down to the Palomar Sky Survey limit and 29% down to the effective 48" Schmidt limit. For S_1.4_<~100mJy the identification fraction remains roughly constant with flux density, contrary to the prediction of higher fractions by some models for cosmological evolution. The magnitude distributions for galaxies plus objects of unknown type generally increase towards fainter magnitudes; the quasar magnitude distributions are also increasing but not as steeply as for the radio galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/741
- Title:
- 150MHz GMRT survey in Eridanus
- Short Name:
- J/MNRAS/390/741
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a 150MHz survey of a field centred on {epsilon} Eridani, undertaken with the Giant Metrewave Radio Telescope (GMRT). The survey covers an area with a diameter of ~2{deg}, has a spatial resolution of ~30arcsec and a noise level of {sigma}=3.1mJy at the pointing centre. These observations provide a deeper and higher resolution view of the 150MHz radio sky than the 7C survey (although the 7C survey covers a much larger area). A total of 113 sources were detected, most are point-like, but 20 are extended. We present an analysis of these sources, in conjunction with the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) telescope Sky Survey (NVSS) (at 1.4GHz) and VLA Low-frequency Sky Survey (VLSS) (at 74MHz). This process allowed us to identify five Ultra-Steep Spectrum (USS) radio sources that are candidate high-redshift radio galaxies (HzRGs). In addition, we have derived the dN/dS distribution for these observations and compare our results with other low-frequency radio surveys.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/650
- Title:
- 325MHz GMRT survey of Herschel-ATLAS/GAMA fields
- Short Name:
- J/MNRAS/435/650
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a 325MHz survey, undertaken with the Giant Metrewave Radio Telescope (GMRT), which covers a large part of the three equatorial fields at 9, 12 and 14.5h of right ascension from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) in the area also covered by the Galaxy And Mass Assembly (GAMA) survey. The full data set, after some observed pointings were removed during the data reduction process, comprises 212 GMRT pointings covering ~90deg^2^ of sky. We have imaged and catalogued the data using a pipeline that automates the process of flagging, calibration, self-calibration and source detection for each of the survey pointings. The resulting images have resolutions of between 14 and 24-arcsec and minimum rms noise (away from bright sources) of ~1mJy/beam, and the catalogue contains 5263 sources brighter than 5{sigma}. We investigate the spectral indices of GMRT sources which are also detected at 1.4GHz and find them to agree broadly with previously published results; there is no evidence for any flattening of the radio spectral index below S_1.4_=10mJy. This work adds to the large amount of available optical and infrared data in the H-ATLAS equatorial fields and will facilitate further study of the low-frequency radio properties of star formation and AGN activity in galaxies out to z~1.
- ID:
- ivo://CDS.VizieR/VIII/98
- Title:
- 180MHz Murchison Commissioning Survey (MWACS)
- Short Name:
- VIII/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Murchison Widefield Array Commissioning Survey (MWACS) is a ~6100deg^2^ 104-196MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The data were combined in the visibility plane before being imaged, and then mosaicked. The survey covers approximately 20.5h<RA<8.5h, -58{deg}<Dec<-14{deg} over three frequency bands centred on 119, 150 and 180MHz. The survey has 3arcmin angular resolution and a typical noise level of 40mJy/beam, with reduced sensitivity near the field boundaries and bright sources. The catalogue consists of flux density and spectral index measurements for 14,110 sources, extracted from the mosaics, 1,247 of which are sub-components of complexes of sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/376/1251
- Title:
- 610MHz observations of Spitzer XFLS
- Short Name:
- J/MNRAS/376/1251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the Spitzer extragalactic First Look Survey field taken at 610MHz with the Giant Metre-wave Radio Telescope are presented. Seven individual pointings were observed, covering a total area of 4 square degrees with a resolution of 5.8x4.7arcsec^2^, PA=60{deg}. The r.m.s. noise at the centre of the pointings is between 27 and 30uJy before correction for the GMRT primary beam. The techniques used for data reduction and production of a mosaicked image of the region are described, and the final mosaic, along with a catalogue of 3944 sources detected above ~5{sigma} are presented. The survey complements existing radio and infrared data available for this region. For further details of the surveys and data analysis procedures please refer to the published paper.
- ID:
- ivo://CDS.VizieR/J/A+A/376/861
- Title:
- 1420MHz radio continuum survey of the southern sky
- Short Name:
- J/A+A/376/861
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of an absolutely calibrated radio continuum survey of the South Celestial Hemisphere at a frequency of 1420MHz are presented. Contour maps show the area 0h<=RA<=24h for the declination range -90{deg} to -10{deg}. Contour steps (50mK T_B_; 3xrms noise) and angular resolution (HPBW 35.4') of the maps match the already existing Stockert telescope Northern Sky Survey at the same frequency (Reich 1982A&AS...48..219R ; Reich & Reich 1986A&AS...63..205R). We compare flux densities of compact and extended sources with published data from the Parkes 64-m telescope and find excellent agreement in general. The survey maps are sensitive enough to constrain synchrotron and thermal emission components which might influence studies of the cosmic microwave background.
