J/MNRAS/352/285 u(bj)r & BV photometry of blue HB stars (Clewley+, 2004)
Distant field blue horizontal branch stars and the mass of the Galaxy -
II. Photometry and spectroscopy of UKST candidates 16<B<19.5, 11<R<52kpc
Clewley L., Warren S.J., Hewett P.C., Norris J.E., Evans N.W.
<Mon. Not. R. Astron. Soc., 352, 285-298 (2004)>
=2004MNRAS.352..285C 2004MNRAS.352..285C
ADC_Keywords: Stars, horizontal branch ; Blue objects ; Photometry, CCD ;
Photometry, UBV ; Radial velocities ; Stars, distances
Keywords: stars: horizontal branch - Galaxy: halo
Abstract:
This is the second in a series of papers presenting a new calculation
of the mass of the Galaxy based on radial velocities and distances for
a sample of faint 16<B<21.3 field blue horizontal-branch (BHB)
stars. We present accurate BV CCD photometry and spectra for 142
candidate A-type stars selected from ubjr photometry of UK Schmidt
telescope plates in six high-Galactic-latitude fields. Classification
of these candidates produces a sample of 60 BHB stars at distances of
11-52kpc from the Sun (mean 28kpc), with heliocentric line-of-sight
velocities accurate to 15km/s, and distance errors <10 per cent. We
provide a summary table listing coordinates and velocities of these
stars.
Description:
To achieve a higher degree of photometric accuracy, BV CCD
observations were made of candidate BHB stars drawn from Table 4. We
made a total of 421 observations of 280 stars over 47 photometric
nights during the period 1998 to 2001.
We obtained medium-resolution optical spectra of 156 survey stars over
a total of 21 clear nights at the 4.2-m William Herschel Telescope
(WHT), La Palma, and the 3.9-m Anglo-Australian Telescope (AAT),
Siding Spring Observatory, Australia.
Regions:
----------------------------------------------
RA (2000) DE Designation(s) (l , b)
----------------------------------------------
0 55 -27 47 SGP 250 -89
2 53 0 12 SA94 175 -50
3 38 -34 50 F358 236 -54
10 23 -00 15 F854 244 45
12 43 -05 16 F789 299 58
22 06 -18 39 MT 37 -51
----------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 64 461 Photometric catalogue of A-type stars selected
from six UKST fields
table7.dat 68 280 Photometric data for the blue horizontal-branch
star candidates, corrected for extinction
table11.dat 88 142 Spectroscopic data for the horizontal-branch
star candidates
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See also:
J/A+AS/109/171 : Blue horizontal branch stars catalog (Flynn+, 1995)
J/AJ/108/1722 : Blue horizontal branch stars (Kinman+ 1994)
J/AJ/127/899 : Blue HB stars in SDSS (Sirko+, 2004)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- [CWH2004] Name
11- 12 I2 h RAh Right ascension (J2000.0)
14- 15 I2 min RAm Right ascension (J2000.0)
17- 21 F5.2 s RAs Right ascension (J2000.0)
23 A1 --- DE- Declination sign (J2000.0)
24- 25 I2 deg DEd Declination (J2000.0)
27- 28 I2 arcmin DEm Declination (J2000.0)
30- 34 F5.2 arcsec DEs Declination (J2000.0)
36- 40 F5.2 mag bjmag bj magnitude (1)
42- 46 F5.2 mag u-bj u-bj colour index (1)
48- 52 F5.2 mag bj-or bj-or colour index (1)
54- 57 F4.2 mag e_u-bj rms uncertainty on u-bj
59- 62 F4.2 mag e_bj-or rms uncertainty on bj-or
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Note (1): UKST filters:
---------------------------------------------------------
Name Wavelength (nm) at transmittances of
1/10 and 9/10 maximum values
---------------------------------------------------------
bj : GG395 365 415
u : UG1 315,390 330,375
or : OG590 580 600
---------------------------------------------------------
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- [CWH2004] Name (1)
10 A1 --- m_[CWH2004] [qv] Multiplicity index on [CWH2004]
12- 13 I2 h RAh Right ascension (J2000.0)
15- 16 I2 min RAm Right ascension (J2000.0)
18- 22 F5.2 s RAs Right ascension (J2000.0)
24 A1 --- DE- Declination sign (J2000.0)
25- 26 I2 deg DEd Declination (J2000.0)
28- 29 I2 arcmin DEm Declination (J2000.0)
31- 35 F5.2 arcsec DEs Declination (J2000.0)
37- 41 F5.2 mag Vmag V magnitude
43- 47 F5.2 mag (B-V)0 Dereddend B-V colour index
49- 53 F5.3 mag e_Vmag rms uncertainty on Vmag
55- 59 F5.3 mag e_(B-V)0 rms uncertainty on (B-V)0
61- 65 F5.3 mag E(B-V) Reddening in B-V
67 I1 --- N Number of photometric nights (2)
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Note (1): Suspected variables are labelled 'V'.
Stars that were subsequently found to be quasars are labelled 'q'.
Stars in the complete sample have names prefixed 'C', otherwise the
stars are prefixed 'I'.
Note (2): The dates and total number of photometric nights 'N' for the
photometric survey in each of the six fields presented in Table 1.
Observations were made using the 1.0-m Jacobus Kapteyn Telescope
(JKT), the 2.5-m Isaac Newton Telescope (INT) and the 2.3-m Telescope
at Siding Spring Observatories (SSO).
----------------------------------------------------------------------
Telescope Date N Fields
-----------------------------------------------------------------------
SSO 1998 Sep 13-16 4 SGP
JKT 1998 Oct 15, 17-20 5 SA94, MTF
SSO 1999 Mar 12-18 7 F854, F789, SGP
JKT 1999 April 4, 7-9 4 F854, F789
SSO 1999 Oct 11-17 7 SGP
JKT 1999 Oct 30-31, Sep 1, 3-5 6 SA94, MTF
SSO 1999 Nov 17-20 4 F358
SSO 2000 Feb 24 4 F854, F789
JKT 2000 Mar 23, 26, 28 3 F854, F789
INT 2001 Mar 29-30, Apr 1 3 SA94, MTF
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- [CWH2004] Name
10 A1 --- n_[CWH2004] [Nbv] Multiplicity index on [CWH2004]
12- 16 F5.2 0.1nm D0.15(gd) D0.15 parameter (1)
18- 21 F4.2 0.1nm e_D0.15(gd) rms uncertainty on D0.15
23- 27 F5.2 0.1nm b(gd) b parameter (1)
29- 32 F4.2 0.1nm c(gd) c parameter (1)
34- 38 F5.2 0.1nm A Semi-major axes of the error ellipse
in the b-c plane (2)
40- 44 F5.3 0.1nm B Semi-minor axes of the error ellipse
in the b-c plane (2)
46- 50 F5.3 rad theta Orientation of the semi-major axis measured
anti-clockwise from the b-axis (2)
52- 55 F4.1 [Sun] [Fe/H] ? Measured metallicity
57- 59 F3.1 [Sun] e_[Fe/H] ? rms uncertainty on [Fe/H]
61- 67 F7.2 km/s HRV Heliocentric radial velocity
69- 72 F4.1 km/s e_HRV rms uncertainty on HRV
74- 77 F4.1 kpc Dist Heliocentric distance
79- 81 F3.1 kpc e_Dist rms uncertainty on Dist
83- 87 A5 --- Class Classification as BHB (blue horizontal-branch)
or A/BS (field blue straggler)
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Note (1): Two methods were developed in paper I (Clemens et al.,
2002MNRAS.337...87C 2002MNRAS.337...87C) to separate the two populations of A stars. Both
methods employ a Sersic function fit to the Hγ and Hδ
absorption lines.
-- The first method, the 'D0.15-colour' method, plots the average of
the width of the two Balmer lines against (B-V)0 colour.
-- The second method, called the scale-width-shape method, plots two
parameters of the Sersic fit, the scale-width b, against the
power-law exponent c.
Note (2): The errors on the parameters b(gd) and c(gd) are provided with
the A, B and theta parameters of the error ellipse.
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Acknowledgements: Lee Clewley, clewley(at)astro.ox.ac.uk
References:
Clewley et al., Paper I 2002MNRAS.337...87C 2002MNRAS.337...87C
(End) Patricia Vannier [CDS] 24-Feb-2005