J/AJ/123/3409 SDSS M, L, and T dwarfs (Hawley+, 2002)
Characterization of M, L, and T dwarfs in the Sloan Digital Sky Survey.
Hawley S.L., Covey K.R., Knapp G.R., Golimowski D.A., Fan X., Anderson S.F.,
Gunn J.E., Harris H.C., Ivezic Z., Long G.M., Lupton R.H., McGehee P.M.,
Narayanan V., Peng E., Schlegel D., Schneider D.P., Spahn E.Y.,
Strauss M.A., Szkody P., Tsvetanov Z., Walkowicz L.M., Brinkmann J.,
Harvanek M., Hennessy G.S., Kleinman S.J., Krzesinski J., Long D.,
Neilsen E.H., Newman P.R., Nitta A., Snedden S.A., York D.G.
<Astron. J. 123, 3409 (2002)>
=2002AJ....123.3409H 2002AJ....123.3409H
ADC_Keywords: Stars, late-type ; MK spectral classification ;
Photometry, infrared
Keywords: stars: late-type - stars: low-mass, brown dwarfs - surveys
Abstract:
An extensive sample of M, L, and T dwarfs identified in the Sloan
Digital Sky Survey (SDSS) has been compiled. The sample of 718 dwarfs
includes 677 new objects (629 M dwarfs and 48 L dwarfs), together with
41 that have been previously published. All new objects and some of
the previously published ones have new optical spectra obtained either
with the SDSS spectrographs or with the Apache Point Observatory 3.5 m
ARC telescope. Spectral types and SDSS colors are available for all
objects; approximately 35% also have near-infrared magnitudes measured
by 2MASS (Two Micron All Sky Survey) or on the Mauna Kea system. We
use this sample to characterize the color-spectral type and color-color
relations of late-type dwarfs in the SDSS filters and to derive
spectroscopic and photometric parallax relations for use in future
studies of the luminosity and mass functions based on SDSS data. We
find that the i*-z* and i*-J colors provide good spectral type and
absolute magnitude (Mi*) estimates for M and L dwarfs. Our distance
estimates for the current sample indicate that SDSS is finding early M
dwarfs out to ∼1.5kpc, L dwarfs to ∼100pc, and T dwarfs to ∼20pc.
The T dwarf photometric data show large scatter and are therefore less
reliable for spectral type and distance estimation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 62 19 Template information
table3.dat 48 27 Average color by spectral type
table4.dat 110 94 SDSS M9, L, and T dwarfs with new optical spectra
spectra.dat 81 53 Spectra list
sp/* . 53 Individual spectra
ml/* . 14 *Sloan templates for M and L stars
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Note on ml/*:
No spectrum is available for L0 type (corrupted file)
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See also:
J/AJ/123/567 : SDSS quasar catalog (Schneider+, 2002)
B/2mass : The 2MASS database (IPAC/UMass, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- SpType Spectral type (G1)
9- 23 A15 --- Name Object name
25- 28 A4 --- Obs Observatory (1)
30- 52 A23 --- Note Alias name
54- 62 A9 --- spFile Name of the Sloan ML template file in
"ml" subdirectory
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Note (1): Observatory as follows:
APO = Apache Point Observatory 3.5m data
Keck = Keck data from Neill Raid, http://www.physics.upenn.edu/~inr,
and described in Kirckpatrick et al., 1999ApJ...519..802K 1999ApJ...519..802K and
2000AJ....120..447K 2000AJ....120..447K
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- SpType Spectral Type (G1)
4- 7 F4.2 mag r*-i* ? r*-i* colour index mean value
9- 12 F4.2 mag e_r*-i* ? rms uncertainty on r*-i* (1)
14- 17 F4.2 mag i*-z* ? i*-z* colour index mean value
19- 22 F4.2 mag e_i*-z* ? rms uncertainty on i*-z* (1)
24- 27 F4.2 mag z*-J ? z*-J colour index mean value
(J: 2MASS magnitude)
29- 32 F4.2 mag e_z*-J ? rms uncertainty on z*-J (1)
34- 37 F4.2 mag i*-J ? i*-J colour index mean value
(J: 2MASS magnitude)
39- 42 F4.2 mag e_i*-J ? rms uncertainty on i*-J (1)
44- 48 F5.2 mag JMAG Absolute 2MASS J magnitude (2)
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Note (1): If there is only one measurement, the rms uncertainty
is set equal to 0.50.
Note (2): The J-band absolute magnitudes come from the calibrated
spectroscopic parallax relation described in Sect. 5.3.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [SDSS]
6- 15 A10 --- SDSS SDSS designation
17- 18 I2 h RAh Right ascension (J2000.0)
20- 21 I2 min RAm Right ascension (J2000.0)
23- 27 F5.2 s RAs Right ascension (J2000.0)
29 A1 --- DE- Declination sign (J2000.0)
30- 31 I2 deg DEd Declination (J2000.0)
33- 34 I2 arcmin DEm Declination (J2000.0)
36- 39 F4.1 arcsec DEs Declination (J2000.0)
41- 45 F5.2 mag r*mag r* magnitude
46 A1 --- u_r*mag Uncertainty flag on r*mag (when e_r*mag>0.5)
47 A1 --- n_r*mag [b] Note on r*mag (1)
49- 53 F5.2 mag i*mag i* magnitude
54 A1 --- u_i*mag Uncertainty flag on i*mag (when e_i*mag>0.2)
55 A1 --- n_i*mag [b] Note on i*mag (1)
57- 61 F5.2 mag z*mag z* magnitude (e_z*mag always lower than 0.2)
63- 67 F5.2 mag Jmag ? J magnitude
68 A1 --- n_Jmag [i] Note on Jmag (2)
70- 74 F5.2 mag Hmag ? H magnitude
75 A1 --- n_Hmag [i] Note on Hmag (2)
77- 81 F5.2 mag Ksmag ? 2MASS Ks magnitude unless otherwise noted
82 A1 --- n_Ksmag [i] Note on KsJmag (2)
84- 85 A2 --- SpType Spectral type (G1)
86 A1 --- n_SpType [j] Note on SpType (3)
88- 93 A6 --- SpType2 Other possible spectral type (G1)
94 A1 --- n_SpType2 [jgmfe] Note on SpType2 (3)
95- 98 A4 --- SpType3 Other possible spectral type (G1)
99 A1 --- n_SpType3 [g] Note on SpType3 (3)
101-106 A6 --- Source Source (4)
108-110 A3 --- n_Source [cdefhklmn, ] Note on Source (3)
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Note (1): b: Magnitude is fainter than formal 5σ limits:
r* = 23.1; i* = 22.3; z* = 20.8
Note (2): i: Near-IR observations reported by Leggett et al.
(2000ApJ...536L..35L 2000ApJ...536L..35L), in the MKO filter system
Note (3): Notes as follows:
c = Position within released 2MASS survey limits.
Object not detected in IR
d = Photometry from preliminary processing of data not contained in
the final SDSS database
e = Identified by, and spectral type from, Gizis et al.
(2000AJ....120.1085G 2000AJ....120.1085G) as 2MASS W J1707+6439
f = Identified by, and spectral type from, Martin et al.
(1999AJ....118.2466M 1999AJ....118.2466M) as DENISp 1159.6+0057
g = Spectral type given by Schneider et al. (2002AJ....123..458S 2002AJ....123..458S)
h = First identified by Schneider et al. (2002AJ....123..458S 2002AJ....123..458S)
j = Spectral type given by Geballe et al. (2002ApJ...564..466G 2002ApJ...564..466G)
k = First identified by Geballe et al. (2002ApJ...564..466G 2002ApJ...564..466G)
l = First identified by Fan et al. (2000AJ....119..928F 2000AJ....119..928F)
m = Identified by, and spectral type from, Kirkpatrick et al.
(2000AJ....120..447K 2000AJ....120..447K) as 2MASS WJ0801+4628
n = First identified by Leggett et al. (2000ApJ...536L..35L 2000ApJ...536L..35L)
Note (4): Sources as follows:
APO = 3.5m ARC telescope at Apache Point Observatory
EDR = SDSS Early Data Release (Stoughton et al., 2002AJ....123..485S 2002AJ....123..485S)
Recent = SDSS spectral database as of 2001 July
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Byte-by-byte Description of file: spectra.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Name Name
26- 27 I2 h RAh Simbad right ascension (J2000)
29- 30 I2 min RAm Simbad right ascension (J2000)
32- 35 F4.1 s RAs Simbad right ascension (J2000)
37 A1 --- DE- Simbad declination sign (J2000)
38- 39 I2 deg DEd Simbad declination (J2000)
41- 42 I2 arcmin DEm Simbad declination (J2000)
44- 45 I2 arcsec DEs Simbad declination (J2000)
47- 81 A35 --- FITSfile Name of the file containing the spectrum
in "sp" subdirectory
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Global notes:
Note (G1): New spectral types (Kirkpatrick et al., 1999ApJ...519..802K 1999ApJ...519..802K):
L = cooler dwarfs where metallic oxides are replaced by metallic
hydrides and neutral alkali metals as the major spectroscopic
signatures.
T = methane-dominated spectral class with Gl 229B as proto-type
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 06-Sep-2002