J/MNRAS/382/515 SDSS ultracool and halo WD candidates (Vidrih+, 2007)
New ultracool and halo white dwarf candidates in SDSS Stripe 82.
Vidrih S., Bramich D.M., Hewett P.C., Evans N.W., Gilmore G., Hodgkin S.,
Smith M., Wyrzykowski L., Belokurov V., Fellhauer M., Irwin M.J.,
Mcmahon R.G., Zucker D., Munn J.A., Lin H., Miknaitis G., Harris H.C.,
Lupton R.H., Schneider D.P.
<Mon. Not. R. Astron. Soc., 382, 515-525 (2007)>
=2007MNRAS.382..515V 2007MNRAS.382..515V
ADC_Keywords: Stars, white dwarf ; Photometry, SDSS ; Proper motions
Keywords: catalogues - stars: atmospheres - stars: evolution - white dwarfs
Abstract:
A 2.5x100°2 region along the celestial equator (Stripe 82) has
been imaged repeatedly from 1998 to 2005 by the Sloan Digital Sky
Survey (SDSS). A new catalogue of ∼4 million light-motion curves,
together with over 200 derived statistical quantities, for objects in
Stripe 82 brighter than r∼21.5 has been constructed by combining these
data by Bramich et al. (2008MNRAS.386..887B 2008MNRAS.386..887B). This catalogue is at
present the deepest catalogue of its kind. Extracting ∼130000 objects
with highest signal-to-noise ratio proper motions, we build a reduced
proper motion diagram to illustrate the scientific promise of the
catalogue. In this diagram, disc and halo subdwarfs are well-separated
from the cool white dwarf sequence. Our sample of 1049 cool white
dwarf candidates includes at least eight and possibly 21 new ultracool
H-rich white dwarfs (Teff<4000K) and one new ultracool He-rich white
dwarf candidate identified from their SDSS optical and UKIDSS infrared
photometry. At least 10 new halo white dwarfs are also identified from
their kinematics.
Description:
SDSS is an imaging and spectroscopic survey that has mapped more than
a quarter of the sky. Imaging data are produced simultaneously in five
photometric bands, namely u, g, r, i and z. The data are processed
through pipelines to measure photometric and astrometric properties .
SDSS Stripe 82 covers a ∼250deg2 area of sky, consisting of a
2.5° strip along the celestial equator from right ascension
-49.5° to +49.5°. The stripe has been repeatedly imaged
between June and December each year from 1998 to 2005. Sixty-two of
the total of 134 available imaging runs were obtained in 2005.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 136 24 Properties of the ultracool white dwarf candidates
table2.dat 133 34 Properties of the halo white dwarf candidates
notes.dat 74 34 Notes
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See also:
II/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2007)
http://www.sdss.org : SDSS Home Page
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- SDSSJ Object SDSS J name (HHMMSS.ss+DDMMSS.s)
19 A1 --- f_SDSSJ [*] Not fully confirmed halo WD candidate (1)
20 A1 --- n_SDSSJ Note on SDSSJ, in notes.dat file
22- 26 F5.2 mag gmag SDSS g magnitude in AB system
28- 31 F4.2 mag e_gmag rms uncertainty on gmag
33- 37 F5.2 mag rmag SDSS r magnitude in AB system
39- 42 F4.2 mag e_rmag rms uncertainty on rmag
44- 48 F5.2 mag imag SDSS i magnitude in AB system
50- 53 F4.2 mag e_imag rms uncertainty on imag
55- 59 F5.2 mag zmag SDSS z magnitude in AB system
61- 64 F4.2 mag e_zmag rms uncertainty on zmag
66- 70 F5.2 mag Jmag ? J magnitude in AB system (2)
72- 75 F4.2 mag e_Jmag ? rms uncertainty on Jmag (2)
77 A1 --- l_Hmag Limit flag on Hmag
78- 82 F5.2 mag Hmag ? H magnitude in AB system (2)
83 A1 --- n_Hmag [c] 5σ detection limit
84- 87 F4.2 mag e_Hmag ? rms uncertainty on Hmag (2)
89 A1 --- l_Kmag Limit flag on Kmag
90- 94 F5.2 mag Kmag ? K magnitude in AB system (2)
95 A1 --- n_Kmag [c] 5σ detection limit
96- 99 F4.2 mag e_Kmag ? rms uncertainty on Kmag (2)
101-104 I4 mas/yr pm Total proper motion
106-107 I2 mas/yr e_pm rms uncertainty on pm
109-111 I3 deg pmPA Proper motion position angle
113-116 I4 pc Dist Heliocentric distance
118-120 I3 km/s Vt Tangential velocity
122-126 I5 K Teff Effective temperature
128-131 F4.1 ---- chi2 chi2 value
133-136 A4 --- Type [H/He ] H-rich and/or He-rich white dwarf
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Note (1): * = Only the best and not also the second best solution predict a
halo white dwarf candidate.
Note (2): The UKIDSS Vega magnitudes are converted to the AB system
adopting a magnitude for Vega of +0.03 and the pass-band zero-point
offsets from Hewett et al. (2006MNRAS.367..454H 2006MNRAS.367..454H).
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1 A1 --- ID Note identification letter
3- 74 A72 --- Note Text of the note
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Nov-2008