J/A+A/670/A124 Circularly polarised LoTSS sources (Callingham+, 2023)
V-LoTSS: The circularly polarised LOFAR Two-metre Sky Survey.
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., Rottgering 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., Chyzy K. T., Drabent A., Emig K.L.,
Gloudemans A.J., Gurkan G., Hajduk M., Hoang D.N., Hoeft M., Iacobelli M.,
Kadler M., Kunert-Bajraszewska M., Mingo B., Morabito L.K., Nair D.G.,
Perez-Torres M., Ray T.P., Riseley C.J., Rowlinson A., Shulevski A.,
Sweijen F., Timmerman R., Vaccari M., Zheng J.
<Astron. Astrophys. 670, A124 (2023)>
=2023A&A...670A.124C 2023A&A...670A.124C (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Polarization ; Radio continuum ; Radio sources
Keywords: surveys - catalogs - radio continuum: general - polarization
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 144MHz LOFAR Two-metre Sky Survey to prodce
circularly polarised maps with a median noise of 140uJy/beam and
resolution of 20-arcsec for 27% of the northern sky (5634deg2). The
leakage of total intensity into circular polarisation is measured to
be ∼0.06%, and our survey is complete at flux densities ≥1mJy. 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.
Description:
The column numbers, names, and units for the V-LoTSS catalogue are
described below. All Stokes I information is similar to that found in
the LoTSS-DR2 catalogue but can differ depending on whether the source
is variable (Shimwell et al., 2022A&A...659A...1S 2022A&A...659A...1S, Cat. J/A+A/659/A1).
For the few sources that are not present in LoTSS-DR2 because of their
variability, we have formed their LoTSS name in line with the
convention defined by (Shimwell et al., 2022A&A...659A...1S 2022A&A...659A...1S, Cat.
J/A+A/659/A1). We report some Gaia DR3 measurements if the Stokes V
source has a counterpart in that survey. Similarly, we report some
pulsar properties if the source has a counterpart in Australia
Telescope National Facility Pulsar Catalogue (PSRCAT; v1.68;
Manchester et al., 2005AJ....129.1993M 2005AJ....129.1993M, Cat. B/psr). Full details can
be found in the paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 561 68 V-LoTSS DR2 flux scaled catalog
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- VLoTSS Name of the source following the naming
convention of LoTSS-DR2,
ILTJHHMMSS.ss+DDMMSS.s (VLoTSS_name)
24- 46 A23 --- Name Name of the source in SIMBAD or PSRCAT
(if known) (Common_name)
48- 66 F19.15 deg RAdeg Stokes V Right ascension (J2000) (RA_v)
68- 86 F19.17 arcsec e_RAdeg rms uncertainty in Stokes V RA (eRAv)
88-105 F18.15 deg DEdeg Stokes V Declination (J2000) (Dec_v)
107-125 F19.17 arcsec e_DEdeg rms uncertainty in Stokes V Declination
(eDecv)
127-145 F19.15 deg RAIdeg Stokes I Right ascension (J2000) (RA_i)
147-166 F20.18 arcsec e_RAIdeg rms uncertainty in Stokes I RA (eRAi)
168-185 F18.15 deg DEIdeg Stokes I Declination (J2000) (Dec_i)
187-206 F20.18 arcsec e_DEIdeg rms uncertainty in Stokes I Declination
(eDeci)
208-218 F11.8 mJy FtotV Integrated Stokes V flux density of the
source (Totalfluxv)
220-230 F11.9 mJy e_FtotV 1-sigma uncertainty on the total Stokes V
flux density (eTotalflux_v)
232-243 F12.8 mJy FtotI Integrated Stokes I flux density of the
source (Totalfluxi)
245-254 F10.8 mJy e_FtotI 1-sigma uncertainty on the total Stokes I
flux density (eTotalflux_i)
256-266 F11.7 % vI Circularly-polarised fraction I (v_i)
268-278 F11.8 % e_vI 1-sigma uncertainty in the
circularly-polarised fraction (vierr)
280-290 F11.9 mJy/beam localrmsV Average background rms value of the source
in Stokes V (localrmsv)
292-302 F11.9 mJy/beam localrmsI Average background rms value of the source
in Stokes I (localrmsi)
304-314 A11 --- Field Field name (field_name)
316-325 A10 "date" Obs.date Date of the LOFAR observation for the
reported field (date_obs)
327-329 F3.1 --- dupdetect Number of independent detections in
different LoTSS fields (dup_detect)
331-358 A28 --- Gaia Gaia DR2 or DR3 source designation,
Gaia DRN NNNNNNNNNNNNNNNNNNN
(designation_gaia)
360-377 F18.14 deg RAGdeg ?=- Gaia DR3 Right ascension (J2000)
(RA_gaia)
379-396 F18.15 deg DEGdeg ?=- Gaia DR3 Declination (J2000) (Dec_gaia)
398-417 F20.16 mas plx ?=- Gaia DR3 parallax (parallax)
419-429 F11.9 mas e_plx ?=- Uncertainty in Gaia DR3 parallax
(e_parallax)
431-441 F11.6 arcsec pm ?=- Gaia DR3 proper motion (pm)
443-448 F6.1 yr refEpGaia ?=- Gaia DR3 reference epoch
(refepochgaia)
450-459 F10.7 mag Gmag ?=- Gaia DR3 G-band mean magnitude
(photgmeanmaggaia)
461-470 F10.8 mag BP-RP ?=- Gaia DR3 BP-RP colour (bprpgaia)
472-490 F19.17 s Per ?=- Period of pulsar in PSRCAT (period_psr)
492-515 E24.16 s e_Per ?=- Uncertainty in the period of pulsar in
PSRCAT (eperiodpsr)
517-538 E22.16 s/s dPer ?=- Period derivative of pulsar in PSRCAT
(periodderivpsr)
540-561 E22.16 s/s e_dPer ?=- Uncertainty in the period derivative of
pulsar in PSRCAT (eperiodderiv_psr)
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Acknowledgements:
Joseph Callingham, jcal(at)strw.leidenuniv.nl
(End) Patricia Vannier [CDS] 26-Dec-2022