V-LoTSS: The circularly polarised LOFAR Two-metre Sky Survey

DOI: 
10.1051/0004-6361/202245567
Publication date: 
15/02/2023
Main author: 
Callingham, J. R.
IAA authors: 
Pérez-Torres, M.
Authors: 
Callingham, J. R.;Shimwell, T. W.;Vedantham, H. K.;Bassa, C. G.;O'Sullivan, S. P.;Yiu, T. W. H.;Bloot, S.;Best, P. N.;Hardcastle, M. J.;Haverkorn, M.;Kavanagh, R. D.;Lamy, L.;Pope, B. J. S.;Röttgering, H. J. A.;Schwarz, D. J.;Tasse, C.;van Weeren, R. J.;White, G. J.;Zarka, P.;Bomans, D. J.;Bonafede, A.;Bonato, M.;Botteon, A.;Bruggen, M.;Chyży, K. T.;Drabent, A.;Emig, K. L.;Gloudemans, A. J.;Gürkan, G.;Hajduk, M.;Hoang, D. N.;Hoeft, M.;Iacobelli, M.;Kadler, M.;Kunert-Bajraszewska, M.;Mingo, B.;Morabito, L. K.;Nair, D. G.;Pérez-Torres, M.;Ray, T. P.;Riseley, C. J.;Rowlinson, A.;Shulevski, A.;Sweijen, F.;Timmerman, R.;Vaccari, M.;Zheng, J.
Journal: 
Astronomy and Astrophysics
Publication type: 
Article
Volume: 
670
Pages: 
A124
Abstract: 
We present the detection of 68 sources from the most sensitive radio survey in circular polarisation conducted to date. We used the second data release of the 144 MHz LOFAR Two-metre Sky Survey to produce circularly polarised maps with a median noise of 140 µJy beam<SUP>−1</SUP> and resolution of 20″ for ≈27% of the northern sky (5634 deg<SUP>2</SUP>). The leakage of total intensity into circular polarisation is measured to be ≈0.06%, and our survey is complete at flux densities ≥1 mJy. A detection is considered reliable when the circularly polarised fraction exceeds 1%. We find the population of circularly polarised sources is composed of four distinct classes: stellar systems, pulsars, active galactic nuclei, and sources unidentified in the literature. The stellar systems can be further separated into chromospherically active stars, M dwarfs, and brown dwarfs. Based on the circularly polarised fraction and lack of an optical counterpart, we show it is possible to infer whether the unidentified sources are likely unknown pulsars or brown dwarfs. By the completion of this survey of the northern sky, we expect to detect 300±100 circularly polarised sources. <P />V-LoTSS catalogue is only available at the CDS via anonymous ftp to <A href="https://cdsarc.cds.unistra.fr/">cdsarc.cds.unistra.fr</A> (ftp://130.79.128.5) or via <A href="https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/670/A124">https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/670/A124</A>
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023A&A...670A.124C/abstract
ADS Bibcode: 
2023A&A...670A.124C
Keywords: 
surveys;catalogs;radio continuum: general;polarization;Astrophysics - Astrophysics of Galaxies;Astrophysics - High Energy Astrophysical Phenomena;Astrophysics - Solar and Stellar Astrophysics