MeerKAT Absorption Line Survey (MALS). I. DR1 Virtual Observatory Resource

Authors
  1. Deka P.P.
  2. Gupta N.
  3. Jagannathan P.
  4. Sekhar S.
  5. Momjian E.
  6. Bhatnagar S.,Wagenveld J.
  7. Klockner H.-R.
  8. Jose J.
  9. Balashev S.A.
  10. Combes F.,Hilton M.
  11. Borgaonkar D.
  12. Chatterjee A.
  13. Emig K.L.
  14. Gaunekar A.N.,Jozsa G.I.G.
  15. Klutse D.Y.
  16. Knowles K.
  17. Krogager J.-K.
  18. Mohapatra A.,Moodley K.
  19. Muller S.
  20. Noterdaeme P.
  21. Petitjean P.
  22. Salas P.,Sikhosana S.
  23. Published by
    CDS
Abstract

The MeerKAT Absorption Line Survey (MALS) has observed 391 telescope pointings at the L band (900-1670MHz) at {delta}<~+20{deg}. We present radio continuum images and a catalog of 495325 (240321) radio sources detected at a signal-to-noise ratio (S/N)>5 over an area of 2289deg^2^ (1132deg^2^) at 1006MHz (1381MHz). Every MALS pointing contains a central bright radio source (S_1GHz_>~0.2Jy). The median spatial resolution is 12" (8"). The median rms noise away from the pointing center is 25{mu}Jy/beam (22{mu}Jy/beam) and is within ~15% of the achievable theoretical sensitivity. The flux density scale ratio and astrometric accuracy deduced from multiply observed sources in MALS are <1% (8% scatter) and 1", respectively. Through comparisons with NVSS and FIRST at 1.4GHz, we establish the catalog's accuracy in the flux density scale and astrometry to be better than 6% (15% scatter) and 0.8", respectively. The median flux density offset is higher (9%) for an alternate beam model based on holographic measurements. The MALS radio source counts at 1.4GHz are in agreement with literature. We estimate spectral indices ({alpha}) of a subset of 125621 sources (S/N>8), confirm the flattening of spectral indices with decreasing flux density, and identify 140 ultra-steep-spectrum ({alpha}{<}-1.3) sources as prospective high-z radio galaxies (z>2). We have identified 1308 variable and 122 transient radio sources comprising primarily active galactic nuclei that demonstrate long-term (26yr) variability in their observed flux densities.

Keywords
  1. radio-continuum-emission
  2. redshifted
  3. surveys
  4. active-galactic-nuclei
Bibliographic source Bibcode
2024ApJS..270...33D
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/270/33
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJS/270/33
Document Object Identifer DOI
doi:10.26093/cds/vizier.22700033

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/270/33
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/270/33
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/270/33
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
IVOA Cone Search SCS
For use with a cone search client (e.g., TOPCAT).
http://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/270/33/catalog?
https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/270/33/catalog?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/270/33/catalog?

History

2024-04-10T08:38:07Z
Resource record created
2024-04-10T08:38:07Z
Created
2024-09-11T20:26:22Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr