J/A+A/589/A49 Photometric brown-dwarf classification (Skrzypek+, 2016)
Photometric brown-dwarf classification.
II. A homogeneous sample of 1361 L and T dwarfs brighter than J = 17.5 with
accurate spectral types.
Skrzypek N., Warren S.J., Faherty J.K.
<Astron. Astrophys. 589, A49 (2016)>
=2016A&A...589A..49S 2016A&A...589A..49S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Stars, late-type ; Photometry, infrared
Keywords: catalogs - surveys - stars: low-mass - brown dwarfs
Abstract:
We present a homogeneous sample of 1361 L and T dwarfs brighter than
J=17.5 (of which 998 are new), from an effective area of 3070deg2,
classified by the photo-type method to an accuracy of one spectral
sub-type using izY JHKW1W2 photometry from SDSS+UKIDSS+WISE. Other
than a small bias in the early L types, the sample is shown to be
effectively complete to the magnitude limit, for all spectral types L0
to T8. The nature of the bias is an incompleteness estimated at 3%
because peculiar blue L dwarfs of type L4 and earlier are classified
late M. There is a corresponding overcompleteness because peculiar red
(likely young) late M dwarfs are classified early L. Contamination of
the sample is confirmed to be small: so far spectroscopy has been
obtained for 19 sources in the catalogue and all are confirmed to be
ultracool dwarfs. We provide coordinates and izY JHKW1W2 photometry of
all sources. We identify an apparent discontinuity, Δm∼0.4mag.,
in the Y-K colour between spectral types L7 and L8. We present
near-infrared spectra of nine sources identified by photo-type as
peculiar, including a new low-gravity source ULAS J005505.68+013436.0,
with spectroscopic classification L2γ. We provide revised
izYJHKW1W2 template colours for late M dwarfs, types M7 to M9.
Description:
Table 3 (L dwarfs) and Table 4 (T dwarfs) provide coordinates and
photometry of the 1281 L dwarfs and 80 T dwarfs, J<17.5, found by
Skrzypek et al. 2016 using the photo-type classification method.
Coordinates and photometry in izYJHKW1W2 (on the Vega system) is
provided, as well as the photo-type classification, and any existing
spectroscopic classification in the literature.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 147 1281 List of L dwarfs
table4.dat 147 80 List of T dwarfs
refs.dat 67 29 References
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Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [ULAS]
6- 24 A19 --- ULAS ULAS designation (JHHMMSS.ss+DDMMSS.s)
26- 30 F5.2 mag imag ?=99 SDSS i magnitude (in Vega)
32- 36 F5.2 mag e_imag ?=99 SDSS i magnitude error (in Vega)
38- 42 F5.2 mag zmag ?=99 SDSS z magnitude (in Vega)
44- 48 F5.2 mag e_zmag ?=99 SDSS z magnitude error (in Vega)
50- 54 F5.2 mag Ymag UKIDSS Y magnitude (in Vega)
56- 60 F5.2 mag e_Ymag UKIDSS Y magnitude error (in Vega)
62- 66 F5.2 mag Jmag UKIDSS J magnitude (in Vega)
68- 72 F5.2 mag e_Jmag UKIDSS J magnitude error (in Vega)
74- 78 F5.2 mag Hmag UKIDSS H magnitude (in Vega)
80- 84 F5.2 mag e_Hmag UKIDSS H magnitude error (in Vega)
86- 90 F5.2 mag Kmag UKIDSS K magnitude (in Vega)
92- 96 F5.2 mag e_Kmag UKIDSS K magnitude error (in Vega)
98-102 F5.2 mag W1mag ?=99 WISE W1 magnitude (in Vega)
104-108 F5.2 mag e_W1mag ?=99 WISE W1 magnitude error (in Vega)
110-114 F5.2 mag W2mag ?=99 WISE W2 magnitude (in Vega)
116-120 F5.2 mag e_W2mag ?=99 WISE W2 magnitude error (in Vega)
122-128 A7 --- PhType Photo-type classification
130-136 F7.2 --- chi2 chi2 value from photo-type classification
138-144 A7 --- SpType Spectral type given in literature (1)
146-147 I2 --- Ref ? Paper it was spectroscopically classified
in, in refs.dat file
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Note (1): In table3.dat, many of the spectral types in ref (6) are not from a
spectrum, rather are estimated from colours.
These are designated uncertain e.g. L3:
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 41 A18 --- Aut Author's name
43- 67 A25 --- Com Comments
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Acknowledgements:
Stephen Warren, s.j.warren(at)imperial.ac.uk
(End) Nat Skrzypek [Imperial College London], Pat Vannier [CDS] 25-Feb-2016