Lockman Hole low-frequency radio sources Virtual Observatory Resource

Authors
  1. Mahony E.K.
  2. Morganti R.
  3. Prandoni I.
  4. Van Bemmel I.M.
  5. Shimwell T.W.,Brienza M.
  6. Best P.N.
  7. Bruggen M.
  8. Calistro Rivera G.
  9. De Gasperin F.,Hardcastle M.J.
  10. Harwood J.J.
  11. Heald G.
  12. Jarvis M.J.
  13. Mandal S.,Miley G.K.
  14. Retana-montenegro E.
  15. Rottgering H.J.A.
  16. Sabater J.
  17. Tasse C.,Van Velzen S.
  18. Van Weeren R.J.
  19. Williams W.L.
  20. White G.J.
  21. Published by
    CDS
Abstract

The Lockman Hole is a well-studied extragalactic field with extensive multi-band ancillary data covering a wide range in frequency, essential for characterizing the physical and evolutionary properties of the various source populations detected in deep radio fields (mainly star-forming galaxies and AGNs). In this paper, we present new 150-MHz observations carried out with the LOw-Frequency ARray (LOFAR), allowing us to explore a new spectral window for the faint radio source population. This 150-MHz image covers an area of 34.7 square degrees with a resolution of 18.6x14.7-arcsec and reaches an rms of 160{mu}Jy/beam at the centre of the field. As expected for a low-frequency selected sample, the vast majority of sources exhibit steep spectra, with a median spectral index of {alpha}_150_^1400^=-0.78+/-0.015. The median spectral index becomes slightly flatter (increasing from {alpha}_150_^1400^=-0.84 to {alpha}_150_^1400^=-0.75) with decreasing flux density down to S_150_ ~10mJy before flattening out and remaining constant below this flux level. For a bright subset of the 150-MHz selected sample, we can trace the spectral properties down to lower frequencies using 60-MHz LOFAR observations, finding tentative evidence for sources to become flatter in spectrum between 60 and 150MHz. Using the deep, multi-frequency data available in the Lockman Hole, we identify a sample of 100 ultra-steep-spectrum sources and 13 peaked-spectrum sources. We estimate that up to 21 per cent of these could have z>4 and are candidate high-z radio galaxies, but further follow-up observations are required to confirm the physical nature of these objects.

Keywords
  1. Surveys
  2. Radio galaxies
  3. Radio continuum emission
Bibliographic source Bibcode
2016MNRAS.463.2997M
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/463/2997
IVOA Identifier IVOID
ivo://CDS.VizieR/J/MNRAS/463/2997

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/463/2997
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/463/2997
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/463/2997
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/MNRAS/463/2997/table4?
https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/463/2997/table4?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/463/2997/table4?

History

2019-05-29T17:11:56Z
Resource record created
2019-05-29T17:11:56Z
Created
2021-11-02T11:21:03Z
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