J/AJ/126/1362 Century Survey Galactic Halo Project. I. (Brown+, 2003)
The Century Survey Galactic Halo Project. I. Stellar spectral analysis.
Brown W.R., Allende Prieto C., Beers T.C., Wilhelm R., Geller M.J.,
Kenyon S.J., Kurtz M.J.
<Astron. J. 126, 1362 (2003)>
=2003AJ....126.1362B 2003AJ....126.1362B
ADC_Keywords: Milky Way ; Stars, blue ; Photometry ; Abundances, [Fe/H] ;
Radial velocities
Keywords: Galaxies: halo - Galaxy: stellar content - stars: abundances -
stars: horizontal-branch
Abstract:
The Century Survey Galactic Halo Project is a photometric and
spectroscopic survey from which we select relatively blue stars
(V-R<0.30mag) as probes of the Milky Way halo. The survey strip spans
the range of Galactic latitude 35°<b<88°, allowing us to study
the nature of populations of stars and their systematic motions as a
function of Galactic latitude. One of our primary goals is to use blue
horizontal-branch stars to trace potential star streams in the halo,
and to test the hierarchical model for the formation of the Galaxy. In
this paper we discuss spectroscopy and multipassband photometry for a
sample of 764 blue stars in the Century Survey region. Our sample
consists predominantly of A- and F-type stars. We describe our
techniques for determination of radial velocities, effective
temperatures, metallicities, and surface gravities. Based on these
measurements, we derive distance estimates by comparison with a set
of calibrated isochrones. We devote special attention to the
classification of blue horizontal-branch stars, and compare the
results obtained from the application of the techniques of Kinman et
al. 1994, Cat. J/AJ/108/1722, Wilhelm et al. (1999, Cat.
J/AJ/117/2308), and Clewley et al. (2002MNRAS.337...87C 2002MNRAS.337...87C). We
identify 55 blue horizontal-branch stars. Our large sample of stars
also uncovers a number of unusual objects, including three
carbon-enhanced stars, a late B-type star located 0.8kpc above the
Galactic plane, and a DZ white dwarf.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 34 33 Comparison with Kinman et al.
(1994, Cat. J/AJ/108/1722)
table4.dat 96 130 The Blue Horizontal Branch (BHB) Selection
table5.dat 105 33 The BHB standards
table6.dat 93 34 Unusual objects
table7.dat 105 737 Photometry
table8.dat 57 737 Spectroscopic Measurements
table9.dat 60 737 Stellar Parameters
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See also:
J/AJ/130/1097 : Century Survey Galactic Halo Project. II. (Brown+, 2005)
J/AJ/108/1722 : Blue horizontal branch stars (Kinman+ 1994)
J/AJ/117/2308 : Spectroscopy of hot stars in the halo (Wilhelm+, 1999)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Stellar identification (G1)
14- 17 F4.2 mag BJA0 This work's BJA0 spectrophotometric index (1)
19- 22 F4.1 0.1nm L0 ? This work's λ0 parameter (2)
25- 28 F4.2 mag K-BJA0 Kinman et al. (1994, J/AJ/108/1722)
BJA0 spectrophotometric index (1)
30- 33 F4.1 0.1nm K-L0 Kinman et al. (1994, J/AJ/108/1722)
λ0 parameter (2)
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Note (1): Quantifies the size of the Balmer jump (Kinman et al., 1994,
Cat. J/AJ/108/1722).
Note (2): Measures the slope of the Balmer jump (Kinman et al., 1994,
Cat. J/AJ/108/1722). In units of Angstroems.
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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 --- --- [CHSS]
6- 8 I3 --- CHSS CHSS number (G2)
12- 15 F4.1 --- SpType Spectral type from this work
17- 19 F3.1 --- e_SpType Error in SpType
21- 24 F4.2 mag BJA0 The BJA0 spectrophotometric index
26- 29 F4.2 mag e_BJA0 Error in BJA0
31 I1 --- BHB1 Classified as BHB by the modified Kinman et
al. (1994, Cat. J/AJ/108/1722) method (2)
33- 36 I4 K Teff Effective temperature
38- 41 I4 K e_Teff Error in Teff
43- 45 F3.1 [cm/s2] log(g) Log of the surface gravity
47- 49 F3.1 [cm/s2] e_log(g) Error in log(g)
51 I1 --- BHB2 Classified as BHB by the Wilhelm et al.
(1999, Cat. J/AJ/117/2308) method (2)
53- 57 F5.2 mag B-V The (B-V)0 color
59- 62 F4.2 mag e_B-V Error in B-V
64- 67 F4.1 0.1nm D0.15 D0.15 value from the Sersic profile fit
69- 71 F3.1 0.1nm e_D0.15 Error in D0.15
73 I1 --- BHB3 Classified as BHB by the Clewley et al.
(2002MNRAS.337...87C 2002MNRAS.337...87C) D0.15-color method (2)
75- 78 F4.2 --- c The power of the Sersic profile fit
80- 83 F4.2 --- e_c Error in c
85- 88 F4.1 0.1nm b Scale length of the Sersic profile fit
in Angstroms
90- 92 F3.1 0.1nm e_b Error in b
94 I1 --- BHB4 Classified as BHB by the Clewley et al.
(2002MNRAS.337...87C 2002MNRAS.337...87C) Scale width - Shape
method (2)
96 I1 --- Tot Sum of the four BHB classification methods (3)
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Note (2): Classified as BHB: 1 = yes; 0 = no.
Note (3): We consider the stars selected by three or more of the four
methods as BHB stars.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Stellar identification (G1) (1)
12- 15 F4.1 --- SpType Spectral type from this work
17- 19 F3.1 --- e_SpType Error in SpType
21- 24 F4.2 mag BJA0 The BJA0 spectrophotometric index
26- 29 F4.2 mag e_BJA0 Error in BJA0
31 I1 --- BHB1 Classified as BHB by the modified Kinman et
al. (1994, Cat. J/AJ/108/1722) method (2)
33- 36 I4 K Teff Effective temperature
38- 41 I4 K e_Teff Error in Teff
43- 45 F3.1 [cm/s2] log(g) Log of the surface gravity
47- 49 F3.1 [cm/s2] e_log(g) Error in log(g)
51 I1 --- BHB2 Classified as BHB by the Wilhelm et al.
(1999, Cat. J/AJ/117/2308) method (2)
53- 57 F5.2 mag B-V The (B-V)0 color
59- 62 F4.2 mag e_B-V Error in B-V
64- 67 F4.1 0.1nm D0.15 D0.15 value from the Sersic profile fit
69- 71 F3.1 0.1nm e_D0.15 Error in D0.15
73 I1 --- BHB3 Classified as BHB by the Clewley et al.
(2002MNRAS.337...87C 2002MNRAS.337...87C) D0.15-color method (2)
75- 78 F4.2 --- c The power of the Sersic profile fit
80- 83 F4.2 --- e_c Error in c
85- 88 F4.1 0.1nm b Scale length of the Sersic profile fit
in Angstroms
90- 92 F3.1 0.1nm e_b Error in b
94 I1 --- BHB4 Classified as BHB by the Clewley et al.
(2002MNRAS.337...87C 2002MNRAS.337...87C) Scale width - Shape
method (2)
96 I1 --- Tot Sum of the four BHB classification methods (3)
98-105 A8 --- Class Classification
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Note (1): Name as in table3.dat
Note (2): Classified as BHB: 1 = yes; 0 = no.
Note (3): We consider the stars selected by three or more of the four
methods as BHB stars.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [CHSS]
6- 8 I3 --- CHSS CHSS number (G2)
10- 16 A7 --- Class Classificiation
18- 19 I2 h RAh Right ascension (J2000.0)
21- 22 I2 min RAm Right ascension (J2000.0)
24- 27 F4.1 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- 37 I2 arcsec DEs Declination (J2000.0)
39- 43 F5.2 mag Vmag ? V magnitude
45- 49 F5.3 mag e_Vmag ? rms uncertainty on Vmag
51- 55 F5.2 mag V-R ? V-R colour index
57- 60 F4.2 mag e_V-R ? rms uncertainty on V-R
62- 66 F5.2 mag Jmag ? J magnitude
68- 71 F4.2 mag e_Jmag ? rms uncertainty on Jmag
73- 77 F5.2 mag J-H ? J-H colour index
79- 82 F4.2 mag e_J-H ? rms uncertainty on J-H
84- 88 F5.2 mag H-K ? H-K colour index
90- 93 F4.2 mag e_H-K ? rms uncertainty on H-K
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [CHSS]
6- 8 I3 --- CHSS CHSS number (G2)
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 20 F4.1 s RAs Second of Right Ascension (J2000)
21 A1 --- DE- Sign of Declination (J2000)
22- 23 I2 deg DEd Degree of Declination (J2000)
25- 26 I2 arcmin DEm Arcminute of Declination (J2000)
28- 29 I2 arcsec DEs Arcsecond of Declination (J2000)
32- 36 F5.2 mag Vmag ? The V band magnitude
38- 42 F5.3 mag e_Vmag ? The error in Vmag
45- 49 F5.2 mag V-R ? The (V-R) color
51- 54 F4.2 mag e_V-R ? The error in V-R
57- 61 F5.2 mag B-V The (B-V)0 color (2)
64- 67 F4.2 mag E(B-V) The E(B-V) reddening value (3)
70- 74 F5.2 mag Jmag ? The J band magnitude (4)
76- 79 F4.2 mag e_Jmag ? The error in Jmag (4)
82- 86 F5.2 mag J-H ? The (J-H) band color (4)
88- 91 F4.2 mag e_J-H ? The error in J-H (4)
94- 98 F5.2 mag H-K ? The (H-K) band color (4)
100-103 F4.2 mag e_H-K ? The error in H-K (4)
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Note (2): Predicted from Balmer line strengths.
Note (3): From Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S), reduced according to our
distance estimate.
Note (4): From the 2MASS Second Data Release, B/2mass, See Cat. II/241.
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [CHSS]
6- 8 I3 --- CHSS CHSS number (G2)
11- 15 F5.2 --- KP KP (Ca II) index (pseudo-equivalent width)
18- 22 F5.2 --- HP2 HP2 (Hδ) index (pseudo-equivalent width)
25- 29 F5.2 --- HG2 ? HG2 (Hγ) index (pseudo-equivalent width)
32- 35 F4.2 --- GP ? The GP (G-band) index (pseudo-equivalent width)
38- 41 F4.1 --- SpType Estimated spectral Type (coded B0=10, A0=20, ...)
43- 45 F3.1 --- e_SpType Error in SpType
47- 52 F6.1 km/s RV Radial velocity
54- 57 F4.1 km/s e_RV The error in RV
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [CHSS]
6- 8 I3 --- CHSS CHSS number (G2)
10 A1 --- f_CHSS [b] Flag on CHSS (2)
12- 15 I4 K Teff Effective temperature
18- 21 F4.2 [cm/s2] log(g) Log of the surface gravity
24- 28 F5.2 [Sun] [Fe/H]GA ? [Fe/H] metallicity from the genetic
algorithm (3)
30- 34 F5.2 [Sun] [Fe/H]KP ? [Fe/H] metallicity from the KP index (3)
36- 40 F5.2 [Sun] [Fe/H]EC ? [Fe/H] metallicity from the equivalent
widths/chi-square spectral match procedure (3)
42- 46 F5.2 [Sun] [Fe/H] ? Final average log [Fe/H] metallicity (3)
47 A1 --- u_[Fe/H] Uncertainty flag on [Fe/H]
49- 53 F5.2 kpc Dist ? Estimated distance
55- 59 F5.2 mag VMAA ? Absolute V band magnitude (4)
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Note (2): Note on CHSS:
b = observed in non-photometric conditions and thus have increased
uncertainty in the Dis column.
Note (3): Ratio relative to the Sun.
Note (4): Corrected for reddening and given the estimated distance.
Where there is no V photometry, the 2MASS J magnitude and the mean
(V-J) color are used for the measured spectral type to estimated VMag.
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Global notes:
Note (G1): In Simbad, RR7 NNN = [KSK94] RR 7 NNN
SA57 NNN = [KSK94] SA 57 NNN
Note (G2): The designation CHSS stands for Century Halo Star Survey and is
chosen to be unique from previous surveys.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 24-Oct-2003