J/ApJ/701/535 A sample of candidate radio stars (Kimball+, 2009)
A sample of candidate radio stars in FIRST and SDSS.
Kimball A.E., Knapp G.R., Ivezic Z., West A.A., Bochanski J.J.,
Plotkin R.M., Gordon M.S.
<Astrophys. J., 701, 535-546 (2009)>
=2009ApJ...701..535K 2009ApJ...701..535K
ADC_Keywords: Stars, radio ; Surveys ; Photometry, SDSS
Keywords: radio continuum: stars - stars: statistics - surveys
Abstract:
We conduct a search for radio stars by combining radio and optical
data from the FIRST survey (Cat. VIII/71) and the Sloan Digital Sky
Survey (SDSS-DR6, Cat. II/282, obsoleted by II/294). The faint limit
of SDSS makes possible a homogeneous search for radio emission from
stars of low optical luminosity. We select a sample of 112 candidate
radio stars in the magnitude range 15<i≲19.1 and with radio flux
S20≥1.25mJy, from about 7000deg2 of sky. The selection criteria
are positional coincidence within 1", radio and optical point source
morphology, and an SDSS spectrum classified as stellar. The sample
contamination is estimated by random matching to be 108±13,
suggesting that at most a small fraction of the selected candidates
are genuine radio stars. Therefore, we rule out a very rare population
of extremely radio-loud stars: no more than 1.2 of every million stars
in the magnitude range 15<i<19.1 stars has radio flux S20≥1.25mJy.
We investigate the optical and radio colors of the sample to find
candidates that show the largest likelihood of being real radio stars.
The significant outliers from the stellar locus, as well as the
magnetically active stars, are the best candidates for follow-up radio
observations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 118 112 Properties of the radio star candidates sample
table2.dat 118 16 Candidate radio stars with resolved radio emission
table3.dat 118 60 Candidate radio stars with complex radio emission
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
VIII/71 : The FIRST Survey Catalog, Version 03Apr11 (Becker+ 2003)
II/199 : Radio continuum emission from stars (Wendker, 1995)
V/67 : An astrometric catalogue of radio stars (Hering+ 1990)
J/A+A/281/161 : Radio emission from stars at 250GHz (Altenhoff+, 1994)
http://www.sdss.org/ : SDSS home page
http://www.atnf.csiro.au/people/rnorris/emu/ : Evolutionary Map of the
Universe project
Byte-by-byte Description of file: table[123].dat
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Bytes Format Units Label Explanations
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1- 11 F11.7 deg RAdeg SDSS Right Ascension in decimal degrees (J2000)
13- 24 F12.8 deg DEdeg SDSS Declination in decimal degrees (J2000)
26- 34 F9.5 deg RAFdeg FIRST Right Ascension in decimal degrees (J2000)
36- 44 F9.5 deg DEFdeg FIRST Declination in decimal degrees (J2000)
46- 49 F4.2 arcsec Sep Separation between SDSS and FIRST positions
51- 60 F10.3 pc Dist Heliocentric distance (1)
62- 63 A2 --- Sp Visually-confirmed MK spectral type
65 A1 --- Ha? [ynm] Spectrum with reliable Hα emission?
(y=yes, n=no, m=maybe)
68- 73 F6.2 mJy Speak FIRST peak 20cm flux density in mJy/beam
75- 80 F6.2 mJy Sint FIRST integrated 20cm flux density
82- 85 F4.1 mag umag SDSS u band model magnitude
87- 90 F4.1 mag gmag SDSS g band model magnitude
92- 95 F4.1 mag rmag SDSS r band model magnitude
97-100 F4.1 mag imag SDSS i band model magnitude
102-105 F4.1 mag zmag SDSS z band model magnitude
107-110 F4.1 --- 4DCD Four-dimensional color distance (3)
112-118 I7 --- [KI2008] Internal identification number (4)
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Note (1): Determined using the photometric parallax relation of
Ivezic et al. (2008ApJ...684..287I 2008ApJ...684..287I); the relation is valid
only for stars on the main sequence.
Note (3): describes the statistical significance of the distance in color
space between a target object and the point on the stellar locus with
the same g–i color as the target; outliers have 4DCD>2, extreme
outliers 4DCD>3. See Section 4.1 of the paper for more details.
Note (4): From the radio catalog of Kimball & Ivezic (2008AJ....136..684K 2008AJ....136..684K).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 08-Sep-2011