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

J. R. Callingham; T. W. Shimwell; H. K. Vedantham; C. G. Bassa; S. P. O’Sullivan; T. W. H. Yiu; S. Bloot; P. N. Best; M. J. Hardcastle; M. Haverkorn; R. D. Kavanagh; L. Lamy; B. J. S. Pope; H. J. A. Röttgering; D. J. Schwarz; C. Tasse; R. J. Van Weeren; G. J. White; P. Zarka; D. J. Bomans; A. Bonafede; M. Bonato; A. Botteon; M. Bruggen; K. T. Chyży; A. Drabent; K. L. Emig; A. J. Gloudemans; G. Gürkan; M. Hajduk; D. N. Hoang; M. Hoeft; M. Iacobelli; M. Kadler; M. Kunert-Bajraszewska; B. Mingo; L. K. Morabito; D. G. Nair; M. Pérez-Torres; T. P. Ray; C. J. Riseley; A. Rowlinson; A. Shulevski; F. Sweijen; R. Timmerman; M. Vaccari; J. Zheng

doi:10.1051/0004-6361/202245567

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

J. R. Callingham^*, T. W. Shimwell, H. K. Vedantham, C. G. Bassa, S. P. O’Sullivan, T. W. H. Yiu, S. Bloot, P. N. Best, M. J. Hardcastle, M. Haverkorn, R. D. Kavanagh, L. Lamy, B. J. S. Pope, H. J. A. Röttgering, D. J. Schwarz, C. Tasse, R. J. Van Weeren, G. J. White, P. Zarka, D. J. BomansA. Bonafede, M. Bonato, A. Botteon, M. Bruggen, K. T. Chyży, A. Drabent, K. L. Emig, A. J. Gloudemans, G. Gürkan, M. Hajduk, D. N. Hoang, M. Hoeft, M. Iacobelli, M. Kadler, M. Kunert-Bajraszewska, B. Mingo, L. K. Morabito, D. G. Nair, M. Pérez-Torres, T. P. Ray, C. J. Riseley, A. Rowlinson, A. Shulevski, F. Sweijen, R. Timmerman, M. Vaccari, J. Zheng

^*Corresponding author for this work

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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^-1 and resolution of 20" for ≈27% of the northern sky (5634 deg²). 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.

Original language	English
Article number	A124
Pages (from-to)	1-15
Number of pages	15
Journal	Astronomy and Astrophysics
Volume	670
DOIs	https://doi.org/10.1051/0004-6361/202245567
Publication status	Published - 1 Feb 2023
Externally published	Yes

Bibliographical note

Keywords

Catalogs
Polarization
Radio continuum: general
Surveys

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10.1051/0004-6361/202245567Licence: CC BY

Publisher version (open access)Final published version, 5.97 MBLicence: CC BY

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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., ... Zheng, J. (2023). V-LoTSS: The circularly polarised LOFAR Two-metre Sky Survey. Astronomy and Astrophysics, 670, 1-15. Article A124. https://doi.org/10.1051/0004-6361/202245567

@article{502b6eb463504541a2a4169da5b6fe5f,

title = "V-LoTSS: The circularly polarised LOFAR Two-metre Sky Survey",

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-1 and resolution of 20{"} for ≈27\% of the northern sky (5634 deg2). 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.",

keywords = "Catalogs, Polarization, Radio continuum: general, Surveys",

author = "Callingham, \{J. R.\} and Shimwell, \{T. W.\} and Vedantham, \{H. K.\} and Bassa, \{C. G.\} and O{\textquoteright}Sullivan, \{S. P.\} and Yiu, \{T. W. H.\} and S. Bloot and Best, \{P. N.\} and Hardcastle, \{M. J.\} and M. Haverkorn and Kavanagh, \{R. D.\} and L. Lamy and Pope, \{B. J. S.\} and R{\"o}ttgering, \{H. J. A.\} and Schwarz, \{D. J.\} and C. Tasse and \{Van Weeren\}, \{R. J.\} and White, \{G. J.\} and P. Zarka and Bomans, \{D. J.\} and A. Bonafede and M. Bonato and A. Botteon and M. Bruggen and Chy{\.z}y, \{K. T.\} and A. Drabent and Emig, \{K. L.\} and Gloudemans, \{A. J.\} and G. G{\"u}rkan and M. Hajduk and Hoang, \{D. N.\} and M. Hoeft and M. Iacobelli and M. Kadler and M. Kunert-Bajraszewska and B. Mingo and Morabito, \{L. K.\} and Nair, \{D. G.\} and M. P{\'e}rez-Torres and Ray, \{T. P.\} and Riseley, \{C. J.\} and A. Rowlinson and A. Shulevski and F. Sweijen and R. Timmerman and M. Vaccari and J. Zheng",

note = "{\textcopyright} 2023 The Authors. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.",

year = "2023",

month = feb,

day = "1",

doi = "10.1051/0004-6361/202245567",

language = "English",

volume = "670",

pages = "1--15",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

}

Callingham, JR, Shimwell, TW, Vedantham, HK, Bassa, CG, O’Sullivan, SP, Yiu, TWH, Bloot, S, Best, PN, Hardcastle, MJ, Haverkorn, M, Kavanagh, RD, Lamy, L, Pope, BJS, Röttgering, HJA, Schwarz, DJ, Tasse, C, Van Weeren, RJ, White, GJ, Zarka, P, Bomans, DJ, Bonafede, A, Bonato, M, Botteon, A, Bruggen, M, Chyży, KT, Drabent, A, Emig, KL, Gloudemans, AJ, Gürkan, G, Hajduk, M, Hoang, DN, Hoeft, M, Iacobelli, M, Kadler, M, Kunert-Bajraszewska, M, Mingo, B, Morabito, LK, Nair, DG, Pérez-Torres, M, Ray, TP, Riseley, CJ, Rowlinson, A, Shulevski, A, Sweijen, F, Timmerman, R, Vaccari, M & Zheng, J 2023, 'V-LoTSS: The circularly polarised LOFAR Two-metre Sky Survey', Astronomy and Astrophysics, vol. 670, A124, pp. 1-15. https://doi.org/10.1051/0004-6361/202245567

TY - JOUR

T1 - V-LoTSS

T2 - The circularly polarised LOFAR Two-metre Sky Survey

AU - Callingham, J. R.

AU - Shimwell, T. W.

AU - Vedantham, H. K.

AU - Bassa, C. G.

AU - O’Sullivan, S. P.

AU - Yiu, T. W. H.

AU - Bloot, S.

AU - Best, P. N.

AU - Hardcastle, M. J.

AU - Haverkorn, M.

AU - Kavanagh, R. D.

AU - Lamy, L.

AU - Pope, B. J. S.

AU - Röttgering, H. J. A.

AU - Schwarz, D. J.

AU - Tasse, C.

AU - Van Weeren, R. J.

AU - White, G. J.

AU - Zarka, P.

AU - Bomans, D. J.

AU - Bonafede, A.

AU - Bonato, M.

AU - Botteon, A.

AU - Bruggen, M.

AU - Chyży, K. T.

AU - Drabent, A.

AU - Emig, K. L.

AU - Gloudemans, A. J.

AU - Gürkan, G.

AU - Hajduk, M.

AU - Hoang, D. N.

AU - Hoeft, M.

AU - Iacobelli, M.

AU - Kadler, M.

AU - Kunert-Bajraszewska, M.

AU - Mingo, B.

AU - Morabito, L. K.

AU - Nair, D. G.

AU - Pérez-Torres, M.

AU - Ray, T. P.

AU - Riseley, C. J.

AU - Rowlinson, A.

AU - Shulevski, A.

AU - Sweijen, F.

AU - Timmerman, R.

AU - Vaccari, M.

AU - Zheng, J.

PY - 2023/2/1

Y1 - 2023/2/1

N2 - 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-1 and resolution of 20" for ≈27% of the northern sky (5634 deg2). 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.

AB - 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-1 and resolution of 20" for ≈27% of the northern sky (5634 deg2). 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.

KW - Catalogs

KW - Polarization

KW - Radio continuum: general

KW - Surveys

UR - https://www.scopus.com/pages/publications/85148673364

U2 - 10.1051/0004-6361/202245567

DO - 10.1051/0004-6361/202245567

M3 - Article

AN - SCOPUS:85148673364

SN - 0004-6361

VL - 670

SP - 1

EP - 15

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A124

ER -

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

Abstract

Bibliographical note

Keywords

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