J/A+A/678/A161 Low-freq. radio emission M dwarfs spectra (Gloudemans+, 2023)
Plausible association of distant late M dwarfs with low-frequency radio
emission.
Gloudemans A.J., Callingham J.R., Duncan K.J., Saxena A., Harikane Y.,
Hill G.J., Zeimann G.R., Rottgering H.J.A., Hardcastle M.J., Pineda J.S.,
Shimwell T.W., Smith D.J.B., Wagenveld J.D.
<Astron. Astrophys. 678, A161 (2023)>
=2023A&A...678A.161G 2023A&A...678A.161G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, M-type ; Radio continuum ; Spectra, optical
Keywords: stars: low-mass - radio continuum: stars - techniques: spectroscopy
Abstract:
We present the serendipitous discovery of 8 distant (>50pc) late M
dwarfs with plausible associated radio emission at 144MHz. The M dwarf
nature of our sources has been confirmed with optical spectroscopy
performed using HET/LRS2 and Subaru/FOCAS, and their radio flux
densities are within the range of 0.5-1.0mJy at 144MHz. Considering
the radio-optical source separation and source densities of the parent
catalogues, we suggest that it is statistically probable the M dwarfs
are associated with the radio emission. However, it remains plausible
that for some of the sources the radio emission originates from an
optically faint and red galaxy hiding behind the M dwarf. The
isotropic radio luminosities (∼1017-18erg/s/Hz) of the M dwarfs
suggest that if the association is real, the radio emission is likely
driven by a coherent emission process produced via plasma or
electron-cyclotron maser instability processes, which is potentially
caused by binary interaction. Long term monitoring in the radio and
high-resolution radio follow-up observations are necessary to search
for any variability and pinpoint the radio emission to determine
whether our tentative conclusion that these ultracool dwarfs are radio
emitting is correct. If the low-frequency radio emission is
conclusively associated with the M dwarfs, this would reveal a new
population of optically faint and distant (>50pc) radio emitting M
dwarfs.
Description:
Properties of the 8 distant M dwarfs, and spectra.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 110 8 Measurements of M dwarfs
list.dat 90 8 List of spectra fits files
fits/* . 8 Individusl fits spectra
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Source name (ILTJJJMM+DDMM)
15- 28 F14.10 deg RAdeg Right ascension Legacy Surveys DR8 (J2000.0)
30- 42 F13.10 deg DEdeg Declination Legacy Surveys DR8 (J2000.0)
44- 57 F14.10 deg RALdeg Right ascension from LoTSS-DR2 (J2000.0)
59- 71 F13.10 deg DELdeg Declination from LoTSS-DR2 (J2000.0)
73- 75 F3.1 arcsec Sep Separation between optical and radio source
77- 80 F4.2 mJy F144MHz Total flux at 144MHz
82- 85 F4.2 mJy e_F144MHz Total flux error at 144MHz
87- 91 F5.2 mag zmag Legacy z-band magnitude
93- 96 F4.2 mag e_zmag Legacy z-band magnitude error
98-103 F6.2 mag Jmag ?=-99 UHS J-band magnitude
105-110 F6.2 mag e_Jmag ?=-99 UHS J-band magnitude error
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Source name
15- 28 F14.10 deg RAdeg Right ascension (J2000.0)
30- 42 F13.10 deg DEdeg Declination (J2000.0)
44- 53 A10 "date" Obs.date Observations date (dd-mm-yyyy)
55- 59 A5 --- Inst Name of instrument
61- 66 A6 --- Tel Name of telescope
68- 90 A23 --- Filename Name of FITS file in subdirectory fits
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Acknowledgements:
Anniek Gloudemans, gloudemans(at)strw.leidenuniv.nl
(End) Anniek Gloudemans [Leiden Univ.], Patricia Vannier [CDS] 16-Aug-2023