J/A+A/373/608 Early-type stars towards the Galactic Center. II. (Dufton+, 2001)
A UKST survey of blue objects towards the Galactic Centre -
seven additional fields.
Dufton P.L., Smartt S.J., Hambly N.C.
<Astron. Astrophys. 373, 608 (2001)>
=2001A&A...373..608D 2001A&A...373..608D
ADC_Keywords: Stars, early-type ; Stars, blue ; Photometry ; Equivalent widths
Keywords: stars: early-type - stars: fundamental parameters - stars: imaging -
galaxy: center
Abstract:
We are searching for early-type stars towards the Galactic centre
which are potentially young objects situated within the inner few
kiloparsecs of the disk. Photographic photometry from the UK Schmidt
Telescope has been used to identify the bluest candidates in nineteen
Schmidt fields (centred close to the Galactic centre). We have
previously obtained FLAIR low dispersion spectroscopy for three of
these fields to estimate spectral types and here we present
spectroscopy for an additional seven fields. Combining the results for
all ten fields, 56 stars were initially classified as early-B type.
Estimates of the equivalent widths of their Balmer and He I lines have
been used to estimate atmospheric parameters and 32 targets have
effective temperatures greater than or equal to 17000K (corresponding
to a spectral type of B3 or earlier). The spectra of seven of these
targets also have absorption lines due to O II and Si III and can be
reliably classified as early-B type. Additionally 78 stars have
estimated effective temperatures between 11000 and 16000K with a
further 50 objects identified as late-B (or early-A) type. All but two
of the early B-type candidates have magnitudes in the range
12.0≤V≤16.0, and our best estimates of their distance suggest that
they could be close to (i.e. Rg<3kpc), or even beyond the Galactic
centre.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 28 10 The 10 Galactic Centre Survey fields for which
spectroscopy has been obtained.
table2.dat 75 58 Blue stellar candidates for Field 279
table3.dat 76 61 Blue stellar candidates for Field 333
table4.dat 75 64 Blue stellar candidates for Field 391
table5.dat 76 64 Blue stellar candidates for Field 520
table6.dat 75 63 Blue stellar candidates for Field 522
table7.dat 75 61 Blue stellar candidates for Field 589
table8.dat 76 61 Blue stellar candidates for Field 591
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See also:
J/A+AS/139/231 : Early-type stars towards the Galactic Centre (Dufton+, 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Field Field number (1)
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 13 I2 s RAs Right ascension (J2000.0)
15 A1 --- DE- Declination sign (J2000.0)
16- 17 I2 deg DEd Declination (J2000.0)
19- 20 I2 arcmin DEm Declination (J2000.0)
22- 24 F3.1 h Blue Blue Exposure times
26- 28 F3.1 h Red ? Red Exposure times
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Note (1): Standard United Kingdom Schmidt Telescope field numbers are
defined in Tritton (1983, United Kingdom Schmidt Telescope Handbook,
Royal Observatory Edinburgh) see also the UKSTU online catalogue at
http://www.roe.ac.uk/
Spectroscopy for the fields 391, 454 and 456 has been discussed
by DSH (Dufton et al., 1999, Cat. J/A+AS/139/231)
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Byte-by-byte Description of file: table[2-8].dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Field Field number
5- 6 I2 --- Star Star number in the field
([DSH2001] FFF-NN in Simbad)
8- 9 I2 h RAh Right ascension (J2000.0)
11- 12 I2 min RAm Right ascension (J2000.0)
14- 18 F5.2 s RAs Right ascension (J2000.0)
20 A1 --- DE- Declination sign (J2000.0)
21- 22 I2 deg DEd Declination (J2000.0)
24- 25 I2 arcmin DEm Declination (J2000.0)
27- 30 F4.1 arcsec DEs Declination sign (J2000.0)
32- 36 F5.2 mag Vmag V magnitude
38- 42 F5.2 mag (u-v) (u-v) colour index
44- 49 I6 --- Cb ? Mean count in the summed spectra for the
wavelength ranges 3900 to 4600Å (blue)
51- 55 I5 --- Cr ? Mean count in the summed spectra for the
wavelength ranges 5600 to 6800Å (red)
57- 66 A10 --- BlueSp Blue spectra classification
69- 78 A10 --- RedSp Red spectra classification
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 10-Sep-2001