J/A+A/585/A141 Galactic center early-type stars catalog (Grosboel, 2016)
A catalog of early-type stars toward the Galactic center.
Grosboel P.
<Astron. Astrophys. 585, A141 (2016)>
=2016A&A...585A.141G 2016A&A...585A.141G
ADC_Keywords: Surveys ; Galactic plane ; Stars, early-type ; Extinction ;
Spectroscopy
Keywords: stars: early-type - dust, extinction - Galaxy: disk -
Galaxy: stellar content - Galaxy: structure - surveys
Abstract:
It is still unclear whether the Sagittarius spiral arm is a major
spiral arm in the Galaxy or whether it just outlines a region of
enhanced star formation because of the local compression of gas. The
best way to separate these scenarios out is to study the kinematics
across the arm to determine the velocity perturbation it induces.
A survey of early-type stars in the direction of the Galactic center
is performed covering an area of 100 sq. deg with the aim of
identifying candidates for a radial velocity study.
Objective prism plates were obtained with the 4° prism on the ESO
Schmidt telescope using IIaO, 4415, and IIIaJ emulsions. The plates
were digitized and more than 100k spectra were extracted down to a
limiting magnitude of B=15m. The spectra were cross-correlated with a
template with Balmer lines, which yielded a candidate list of 12675
early-type stars. Magnitudes and equivalent widths of strong lines
were calculated from the spectra, which allowed us to estimate the
individual extinctions and distances for 11075 stars.
Description:
Catalog of 12675 early-type stars with Balmer lines and B<15mag in a
100 square degree field toward the Galactic center identified on
objective prism plates obtained at the 1m ESO Schmidt telescope at La
Silla, Chile. The typical positional error is 1" perpendicular to the
dispersion direction (i.e. right ascension) while it is 6" along the
dispersion (i.e. declination). A 10 character scan identifier is
provided consisting of the five digit ESO plate number, a letter
indicating the plate scan section (i.e. a-d), and finally a 4 digit
sequence number of the detection. Apparent B magnitude is given with a
mean error of 0.2mag. Johnson's (U-B), Stroemgren's (u-v) and (v-b)
color indices have all errors around 0.2mag. Equivalent width of
Balmer lines (i.e. Hgamma, Hdelta, and Hepsilon) and the CaII K-line
are listed with mean errors of the order of 0.2nm. Visual extinction
and effective temperature are given for stars with (v-b)-(u-b) colors
which are consistent with them being reddened from the "zero-age"
mean-sequence (ZAMS) given by Marigo et al. (2008A&A...482..883M 2008A&A...482..883M) for
solar abundances. For B stars, the equivalent width of Hgamma was used
to estimate the magnitude above the ZAMS, dBmag. Applying this
correction, when available, the absolute B magnitude and distance were
calculated as listed. Typical errors in distance are 30%. The scans of
the objective prism spectra are provided in relative intensities with
a linear step size of 10um corresponding to 0.456nm in wavelength at
Hγ. The start of the spectral scans is relative to the Hγ
line.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ets_tgc.dat 148 12675 Catalog of early-type stars toward the
Galactic center
ets_tgc.fit 2880 18062 Catalog of early-type stars toward the
Galactic center with spectra in fits format
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Byte-by-byte Description of file: ets_tgc.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [OPS]
4- 17 A14 --- OPS Objective Prism Survey identifier,
HHMMSSs+ddMMSS (J2000)
19- 27 F9.5 deg RAdeg Right Ascension (J2000)
29- 37 F9.5 deg DEdeg Declination (J2000)
39- 48 A10 --- IdScan Scan identifier
51- 55 F5.2 mag Bmag [9/17.5] Johnson B-band magnitude (apparent)
58- 62 F5.2 mag U-B [-2.3/2.7]? Johnson (U-B) index
65- 69 F5.2 mag u-v [-0.7/5.6]? Stroemgren (u-v) index
72- 76 F5.2 mag v-b [-0.1/1.3]? Stroemgren (v-b) index
78- 82 F5.2 nm EWHg [0.1/3.3] Equivalent width of Hγ-line
84- 88 F5.2 nm EWHd [0.1/3.0] Equivalent width of Hδ-line
90- 94 F5.2 nm EWHe [0.0/2.6] Equivalent width of Hε-line
96-100 F5.2 nm EWCa [0.0/3.0] Equivalent width of CaII K-line
103-107 F5.2 mag AV [-0.31/6.1]?=- Extinction in V
109-113 F5.2 [K] logTe [3.7/4.9]?=- Effective temperature
115-119 F5.2 mag dBmag [-1.2/0] Magnitude above ZAMS in Johnson B filter
122-127 F6.2 mag BMAG [-11/5.4]? Absolute Magnitude in Johnson B filter
130-136 F7.3 kpc Dist [0.06/172]?=- Distance from Sun
139-145 F7.1 um Start [-8300/-3120] Start of spectral scan
relative to Hγ
147-148 I2 um Step [10] Step size of spectral scan
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Acknowledgements:
Preben Grosboel, pgrosbol(at)eso.org
History:
* 12-Jan-2016: First on-line version
* 15-Jan=2016: Corrected names version
(End) Preben Grosboel [ESO], Patricia Vannier [CDS] 03-Dec-2015