J/AJ/131/2722 New L and T dwarfs from the SDSS (Chiu+, 2006)
Seventy-one new L and T dwarfs from the Sloan Digital Sky Survey.
Chiu K., Fan X., Leggett S.K., Golimowski D.A., Zheng W., Geballe T.R.,
Schneider D.P., Brinkmann J.
<Astron. J., 131, 2722-2736 (2006)>
=2006AJ....131.2722C 2006AJ....131.2722C
ADC_Keywords: Stars, dwarfs ; Infrared sources ; Spectral types ;
Photometry, SDSS
Keywords: infrared: stars - stars: low-mass, brown dwarfs
Abstract:
We present near-infrared observations of 71 newly discovered L and T
dwarfs, selected from imaging data of the Sloan Digital Sky Survey
(SDSS) using the i-dropout technique. Sixty-five of these dwarfs have
been classified spectroscopically according to the near-infrared L
dwarf classification scheme of Geballe et al. (2002ApJ...564..466G 2002ApJ...564..466G)
and the unified T dwarf classification scheme of Burgasser et al.
(2006, Cat. J/ApJ/637/1067). The spectral types of these dwarfs
range from L3 to T7 and include the latest types yet found in the
SDSS. Six of the newly identified dwarfs are classified as early to
mid-L dwarfs according to their photometric near-infrared colors, and
two others are classified photometrically as M dwarfs. We also present
new near-infrared spectra for five previously published SDSS L and T
dwarfs, and one L dwarf and one T dwarf discovered by Burgasser et al.
(2006, Cat. J/ApJ/637/1067) from the Two Micron All Sky Survey. The
new SDSS sample includes 27 T dwarfs and 30 dwarfs with spectral types
spanning the complex L-T transition (L7-T3).
Description:
We obtained z-band images with the SPICAM imager on the Astrophysical
Research Consortium (ARC) 3.5m telescope at the Apache Point
Observatory. We obtained J-band images with the 256x256 NICMOS camera
on Steward Observatory's 2.3m Bok Telescope, and the GRIM II and
NIC-FPS imagers on the ARC 3.5m telescope. The candidates were imaged
through the Mauna Kea Observatory (MKO) J, H, and K bands using the
United Kingdom Infrared Telescope (UKIRT) Fast-Track Imager or the
NASA Infrared Telescope Facility (IRTF) imager/spectrometer SpeX.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 127 77 New M, L, and T dwarf photometry
table2.dat 127 10 Additional ZJHK photometry
table3.dat 126 61 Spectral indices of L-T1 dwarfs
(Geballe et al. (2002ApJ...564..466G 2002ApJ...564..466G) scheme)
table4.dat 136 43 Spectral indices of L8-T dwarfs (Burgasser et
al., 2006 (Cat. J/ApJ/637/1067) scheme)
table5.dat 102 73 L and T Dwarf colors versus spectral type
--------------------------------------------------------------------------------
See also:
http://www.sdss.org : SDSS Home Page
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/ApJ/637/1067 : T dwarf NIR spectral classification (Burgasser+, 2006)
J/AJ/127/3553 : JHK photometry and spectroscopy for L and T dwarfs
(Knapp+, 2004)
J/ApJ/564/421 : Spectra of T dwarfs. I. (Burgasser+, 2002)
J/AJ/126/2487 : T dwarfs in the southern hemisphere (Burgasser+, 2003)
Byte-by-byte Description of file: table1.dat table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Source identification
25- 26 A2 --- m_Name Multiple index on Name
28 A1 --- n_Name Photometrically identified star (1)
30- 34 F5.2 mag imag ? SDSS i band AB magnitude
36- 39 F4.2 mag e_imag ? Uncertainty in imag
40 A1 --- f_imag []] Denotes a asinh magnitude of a dwarf
not detected in SDSS
42- 46 F5.2 mag zmag ? SDSS z band AB magnitude
48- 51 F4.2 mag e_zmag ? Uncertainty in zmag
53- 56 I4 --- Run ? SDSS run number
58- 67 A10 "YYYY/MM/DD" Obs1 UT Date of SDSS observation
69- 73 F5.2 mag Zmag ? United Kingdom Infrared Telecope's
Fast-Track Imager Z band magnitude
(0.850-1.055{um}m)
75- 78 F4.2 mag e_Zmag ? Uncertainty in Zmag
80- 84 F5.2 mag Jmag ? Mauna Kea Observatory J band Vega magnitude
86- 89 F4.2 mag e_Jmag ? Uncertainty in Jmag
91- 95 F5.2 mag Hmag ? Mauna Kea Observatory H band Vega magnitude
97-100 F4.2 mag e_Hmag ? Uncertainty in Hmag
102-106 F5.2 mag Kmag ? Mauna Kea Observatory K band Vega magnitude
108-111 F4.2 mag e_Kmag ? Uncertainty in Kmag
113-116 A4 --- Inst Mauna Kea Observatory instrument used (3)
118-127 A10 "YYYY/MM/DD" Obs2 UT Date of MKO observation
--------------------------------------------------------------------------------
Note (1): Note on SDSS, defined as follows:
b = Photometrically identified M dwarf; no spectrum obtained.
c = Photometrically identified mid-L dwarf; no spectrum obtained.
d = Photometrically identified early-L dwarf; no spectrum obtained.
Note (3): Mauna Kea Observatory instrument used:
UFTI = United Kingdom Infrared Telecope's Fast-Track Imager;
SpeX = NASA Infrared Telescope Facility's imager/spectrometer SpeX.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Source identification
25- 26 A2 --- m_Name Multiple index on Name
28- 31 F4.2 --- H2OJ ? The H2O-J index
32 A1 --- u_H2OJ [:] Uncertainty flag on H2OJ (1)
34- 38 A5 --- Sp1 The H2O-J spectral type (1)
40- 43 F4.2 --- CH4J ? The CH4-J index
45- 50 A6 --- Sp2 The CH4-J spectral type
52- 55 F4.2 --- H2OH ? The H2O-H index (1)
56 A1 --- u_H2OH [:] Uncertainty flag on H2OH (1)
58- 62 A5 --- Sp3 The H2O-H spectral type (1)
64- 67 F4.2 --- CH4H ? The CH4-H index (1)
68 A1 --- u_CH4H [:] Uncertainty flag on CH4H (1)
70- 73 A4 --- Sp4 The CH4-H spectral type (1)
75- 78 F4.2 --- CH4K ? The CH4-K index
80- 83 A4 --- Sp5 The CH4-K spectral type
85- 96 A12 --- SpType Mean spectral type (G1)
98-136 A39 --- Com Instrument and observation information (2)
--------------------------------------------------------------------------------
Note (1): Uncertain values have not been included in the final spectral
classification.
Note (2): Dates are UT and in yymmdd format.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 24 A24 --- Name Source identification
25- 26 A2 --- m_Name Multiple index on Name
28 A1 --- n_Name Note on Name (1)
30- 41 A12 --- SpType Spectral type (G1)
43 A1 --- l_i-z The 5σ lower limit flag on i-z (2)
45- 48 F4.2 mag i-z ? The (i-z) color index
50- 53 F4.2 mag e_i-z ? Uncertainty in i-z
55- 58 F4.2 mag z-J ? The (z-J) color index
60- 63 F4.2 mag e_z-J ? Uncertainty in z-J
65- 69 F5.2 mag J-H The (J-H) color index
71- 74 F4.2 mag e_J-H Uncertainty in J-H
76- 80 F5.2 mag H-K The (H-K) color index
82- 85 F4.2 mag e_H-K Uncertainty in H-K
87- 91 F5.2 mag J-K The (J-K) color index
93- 96 F4.2 mag e_J-K Uncertainty in J-K
98-102 F5.2 mag Jmag The J band magnitude (3)
--------------------------------------------------------------------------------
Note (1): Note on Name, defined as follows:
d = Identified by Liu et al. (2006ApJ...647.1393L 2006ApJ...647.1393L) as a close
binary with T1-T2 and T5-T6 components;
e = Spectral type from Burgasser et al. (2006, Cat. J/ApJ/637/1067).
Note (2): The i-z colors of dwarfs not detected in i are calculated using
5σ detection limit of i=22.5.
Note (3): Errors are typically 0.03mag, also refer to Table 1.
--------------------------------------------------------------------------------
Global Notes:
Note (G1): Uncertainties in spectral types are ±0.5 subtype, unless otherwise
noted.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 07-Sep-2007