J/AJ/136/2321 Washington photometry of Bootes I stars (Hughes+, 2008)
The age and metallicity of the Bootes I system.
Hughes J., Wallerstein G., Bossi A.
<Astron. J., 136, 2321-2331 (2008)>
=2008AJ....136.2321H 2008AJ....136.2321H
ADC_Keywords: Galaxies, photometry ; Populations, stellar ;
Photometry, CMT1T2V
Keywords: galaxies: dwarf - galaxies: individual (Bootes I) - Local Group
Abstract:
We present Washington CT1T2 photometry of a field central to the
Bootes I dwarf spheroidal galaxy, which was discovered as a stellar
overdensity in the Sloan Digital Sky Survey (DR5). We show that the
Washington filters are much more effective than the Sloan filters in
separating the metal-poor turn-off stars in the dwarf galaxy from
the foreground stars. We detect 165 objects in the field, and
statistically determine that just over 40% of the objects are
nonmembers. Our statistical analysis mostly agrees with radial
velocity measurements of the brighter stars. We find that there is a
distinct main-sequence turn-off and subgiant branch, where there is
some evidence of a spread in chemical abundance.
Description:
We observed one field centered on (RA=14:00:06, DE=14:5; J2000) with
the Apache Point Observatory (APO) 3.5m telescope, using the
direct-imaging SPIcam system.
The data set for Bootes I was taken on 2007 March 19.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 111 165 Sample of objects in Bootes I central field
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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 I3 --- Seq Running identification number,
<[HWB2008] NNN> in Simbad
5- 11 F7.3 pix Xpix X pixel coordinate
13- 20 F8.3 pix Ypix Y pixel coordinate
22- 27 F6.3 mag T1mag Washington T1 band magnitude
29- 33 F5.3 mag e_T1mag The 1σ error in T1mag
35- 40 F6.3 mag Cmag Washington C band magnitude
42- 46 F5.3 mag e_Cmag The 1σ error in Cmag
48- 53 F6.3 mag T2mag Washington T2 band magnitude
55- 59 F5.3 mag e_T2mag The 1σ error in T2mag
61- 62 I2 h RAh Hour of Right Ascension (J2000)
64- 65 I2 min RAm Minute of Right Ascension (J2000)
67- 71 F5.2 s RAs Second of Right Ascension (J2000)
73- 74 I2 deg DEd Degree of Declination (J2000)
76- 77 I2 arcmin DEm Arcminute of Declination (J2000)
79- 82 F4.1 arcsec DEs Arcsecond of Declination (J2000)
84 A1 --- n_Seq [A-F] Star status (1)
86-111 A26 --- Remarks Additional information on star (1)
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Note (1): Source type code as follows:
A = Source has passed statistical cleaning and color-selection, and has an
uncertainties better than 0.05 in all filters
B = Source has passed statistical cleaning and color-selection, does not
have uncertainties better than 0.05 in all filters
C = Source has passed color-selection, failed statistical cleaning, and
has uncertainties better than 0.05 in all filters
D = Source has passed color-selection, failed statistical cleaning, and
does not have uncertainties better than 0.05 in all filters
E = Source has passed statistical cleaning but failed color selection.
F = Source has failed statistical cleaning and color selection
VA = Source accepted by Martin et al.'s (2007, Cat. J/MNRAS/380/281)
radial velocity study
VR = Source rejected by Martin et al.'s (2007, Cat. J/MNRAS/380/281)
radial velocity study
BSS = Possibly a blue straggler star
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 26-May-2011