J/A+A/598/A92 New ultracool subdwarfs (Lodieu+, 2017)
New ultracool subdwarfs identified in large-scale surveys using VO tools.
II. SDSS DR7 vs. UKIDSS LAS DR6, SDSS DR7 vs. UKIDSS LAS DR8,
SDSS DR9 vs. UKIDSS LAS DR10, and SDSS DR7 vs. 2MASS.
Lodieu N., Espinoza Contreras M., Zapatero Osorio M.R., Solano E.,
Aberasturi M., Martin E.L.
<Astron. Astrophys. 598, A92 (2017)>
=2017A&A...598A..92L 2017A&A...598A..92L (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Stars, late-type ; Photometry, SDSS ;
Photometry, infrared ; Proper motions ; Spectroscopy
Keywords: Galaxy: halo - subdwarfs - techniques: photometric -
techniques: spectroscopic - virtual observatory tools
Abstract:
We developed an efficient method to search for late-type subdwarfs. We
carried out a search cross-matching SDSS, 2MASS, and UKIDSS with VO
tools. We considered different photometric and proper motion criteria
for our selection. We identified 100 late-type subdwarf candidates. We
obtained our own low-resolution optical spectra for 71 of our
candidates and retrieved Sloan spectra for 30 of them (9 in common to
the 71). We classified 92 candidates based on optical spectra. Our new
discoveries include 49 subdwarfs, 25 extreme subdwarfs, six
ultrasubdwarfs, one subdwarf/extreme subdwarf, and two
dwarfs/subdwarfs. In addition, we discovered three early-L subdwarfs.
We double the numbers of cool subdwarfs and derived a surface density
of late-type subdwarfs.
Description:
Optical spectra of 92 late-type dwarfs from GTC/OSIRIS, VLT/FORS2,
NOT/ALFOSC, and SDSS. Each file contains wavelength (in Angstroms) and
the flux (in ergs/cm2/sec/Angstrom) in the first and second column,
respectively. Fluxes are normalised at 1.0 at 7500 Angstroms. Names of
files are composed of ID number followed by HHMMsDDMM of the
coordinates of the object (where 's' is the sign) Tables 1, 2, and 4
of the paper are available through CDS. The data presented in this
paper and CDS are also gathered in a VO-compliant archive at
http://svo2.cab.inta-csic.es/vocats/ltsa/ and include even more
options for visualisation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 157 100 ID, coordinates, photometry, and proper motions
table2.dat 82 87 ID, proper motion, and reduced proper motions
table4.dat 114 101 ID,TiO5,CaH1,CaH2,CaH3,SpT,d,Vh,U,V,W
sp/* . 101 Individual spectra
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See also:
J/A+A/493/L27 : Parallaxes of 10 ultracool subdwarfs (Schilbach+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I03 --- ID ID number
5- 6 I2 h RAh Right ascension (J2000.0)
8- 9 I2 min RAm Right ascension (J2000.0)
11- 15 F5.2 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 27 F4.1 arcsec DEs Declination (J2000.0)
29- 34 F6.3 mag umag SDSS u magnitude
36- 40 F5.3 mag e_umag Error on the SDSS u magnitude
42- 47 F6.3 mag gmag SDSS g magnitude
49- 53 F5.3 mag e_gmag Error on the SDSS g magnitude
55- 60 F6.3 mag rmag SDSS r magnitude
62- 66 F5.3 mag e_rmag Error on the SDSS r magnitude
68- 73 F6.3 mag imag SDSS i magnitude
75- 79 F5.3 mag e_imag Error on the SDSS i magnitude
81- 86 F6.3 mag zmag SDSS z magnitude
88- 92 F5.3 mag e_zmag Error on the SDSS z magnitude
94- 99 F6.3 mag Ymag ?=99.999 UKIDSS Y magnitude
101-105 F5.3 mag e_Ymag ?=9.999 Error on the UKIDSS Y magnitude
107-112 F6.3 mag Jmag 2MASS or UKIDSS J magnitude
114-118 F5.3 mag e_Jmag Error on the 2MASS or UKIDSS J magnitude
120-125 F6.3 mag Hmag ?=99.999 2MASS or UKIDSS H magnitude
127-131 F5.3 mag e_Hmag ?=9.999 Error on the 2MASS or UKIDSS H magnitude
133-138 F6.3 mag Kmag 2MASS or UKIDSS K magnitude
140-144 F5.3 mag e_Kmag Error on the 2MASS or UKIDSS K magnitude
146-150 F5.3 arcsec/yr pm Total proper motion
152-157 F6.3 mag Hr Reduced proper motion
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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- 3 I03 --- ID ID number
5- 9 F5.3 arcsec/yr pmVO Proper motion from the VO
11- 16 F6.3 mag HrVO Reduced proper motion from the VO
18- 23 F6.3 arcsec/yr pmRA Proper motion in RA from images
25- 29 F5.3 arcsec/yr e_pmRA Error on proper motion in RA from images
31- 37 F7.4 arcsec/yr pmDE Proper motion in dec from images
39- 43 F5.3 arcsec/yr e_pmDE Error on proper motion in DE from images
45- 49 F5.3 arcsec/yr pm Revised total proper motion
51- 55 F5.3 arcsec/yr e_pm Error on revised total proper motion
57- 62 F6.3 deg Hr Revised reduced proper motion
64- 68 F5.3 deg e_Hr Error on revised Hr
70- 75 F6.3 deg b_Hr Minimum value of Hr
77- 82 F6.3 deg B_Hr Maximum value on Hr
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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- 3 I03 --- ID ID number
5- 9 F5.3 --- TiO5 TiO5 index
11- 15 F5.3 --- CaH1 CaH1 index
17- 21 F5.3 --- CaH2 CaH2 index
23- 27 F5.3 --- CaH3 CaH3 index
29- 36 A8 --- SpTypeL Spectral type based on Lepine's scheme
38- 51 A14 --- SpType Adopted spectral type
53- 56 A4 --- Tel Telescope
58- 62 F5.1 pc Dist ?=999.9 Distance
64- 68 F5.1 pc e_Dist ?=99.9 Error on the distance
70- 73 I4 km/s HV ?=999 Heliocentric velocity
75- 77 I3 km/s e_HV ?=99 Error on the heliocentric velocity
79- 84 F6.1 km/s Uvel ?=999.9 Space motion: U component
86- 89 F4.1 km/s e_Uvel ?=99.9 Space motion: error on U component
91- 96 F6.1 km/s Vvel ?=999.9 Space motion: V component
98-102 F5.1 km/s e_Vvel ?=99.9 Space motion: error on V component
104-109 F6.1 km/s Wvel ?=999.9 Space motion: W component
111-114 F4.1 km/s e_Wvel ?=99.9 Space motion: error on W component
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 19 F19.13 0.1nm Lambda Wavelength (in Angstroms)
21- 44 E24.18 10mW/m2/nm Flux Flux (in ergs/cm2/s/Å)
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Acknowledgements:
Nicolas Lodieu, nlodieu(at)iac.es
References:
Lodieu et al., Paper I 2012A&A...542A.105L 2012A&A...542A.105L
(End) Nicolas Lodieu [IAC, Tenerife, Spain], Patricia Vannier [CDS] 17-Oct-2016