J/MNRAS/332/441 FAUST UV sources towards Ophiuchus (Formiggini+, 2002)
Hidden subluminous stars among the FAUST UV sources towards Ophiuchus.
Formiggini L., Brosch N., Almoznino E., Bowyer S., Lampton M.
<Mon. Not. R. Astron. Soc. 332, 441 (2002)>
=2002MNRAS.332..441F 2002MNRAS.332..441F
ADC_Keywords: Stars, white dwarf ; Ultraviolet ; Photometry ;
Parallaxes, trigonometric ; Proper motions
Keywords: subdwarfs - white dwarfs - Galaxy: stellar content -
ultraviolet: stars
Abstract:
We present results of an analysis of a UV image in the direction of
Ophiuchus, obtained with the FAUST instrument. The image contains 228
UV sources. Most of these are identified as normal early-type stars
through correlations with catalogued objects. For the first time in
this project we identify UV sources as such stars by selecting
suitable candidates in crowded fields as the bluest objects in
colour-colour diagrams using observations from the Wise Observatory.
These candidates are then studied using low-resolution spectroscopy,
which allows the determination of spectral types to an accuracy of
about one-half class, for 60 stars. Synthetic photometry of spectral
data is performed in order to predict the expected UV emission, on the
basis of the photometric information. These results are used along
with the Hipparcos/Tycho (I/239) information, to search for
subluminous stars. The comparison of the predicted emission with the
FAUST measured magnitudes allows us to select 12 stars as highly
probable evolved hot stars. High signal-to-noise spectra are obtained
for nine of these stars, and Balmer line profiles are compared with
the prediction of atmosphere models and with the spectrum of real
stellar atmospheres. Among the nine candidates, six are classified as
previously unrecognized sdB stars, and two as white dwarfs. Our result
indicates that indeed more bright subluminous stars are still
unrecognized in the existing samples.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 45 228 Derived FAUST sources in the Ophiuchus field
table2.dat 75 230 Identified FAUST sources
table4.dat 65 46 Hipparcos data
table5.dat 45 12 Candidates subluminous stars
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See also:
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/A+A/372/173 : ISOCAM observations of rho Ophiuchi cloud (Bontemps+, 2001)
J/ApJ/438/813 : Stellar population in ρ Oph cloud core (Strom+, 1995)
J/ApJ/566/993 : HST/NICMOS survey of Ophiuchus cloud (Allen+, 2002)
J/ApJS/96/461 : Far-UV Point Sources from FAUST (Bowyer+ 1995)
J/ApJS/104/101 : Far-UV stellar photometry (Schmidt+, 1996)
J/ApJS/112/109 : Rho Oph Near IR Positions and Photometry (Barsony+, 1997)
J/MNRAS/316/326 : Redshifts of Ophiuchus region galaxies (Hasegawa+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [FBA2002] Identification (sequential number)
5- 6 I2 h RAh Right ascension (J2000.0)
8- 9 I2 min RAm Right ascension (J2000.0)
11- 15 F5.2 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 28 F5.2 arcsec DEs Declination (J2000.0)
30- 34 F5.2 mag UVmag FAUST UV magnitude
36- 39 F4.2 mag e_UVmag rms uncertainty on UVmag
41- 44 I4 --- FAUST ? FAUST number
45 A1 --- n_FAUST [*] * when no FAUST number
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- [FBA2002] Identification (sequential number)
4 A1 --- n_[FBA2002] [*] * indicates two identifications proposed
5- 6 I2 h RAh Right ascension (J2000.0)
8- 9 I2 min RAm Right ascension (J2000.0)
11- 15 F5.2 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 28 F5.2 arcsec DEs Declination (J2000.0)
30- 49 A20 --- ID Proposed star identification
51- 60 A10 --- SpType MK spectral type
62 A1 --- l_Bmag Limit flag on Bmag
63- 68 F6.3 mag Bmag ? Blue magnitude
70- 75 F6.3 mag Vmag ? Visual magnitude
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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- 3 I3 --- [FBA2002] Identification (sequential number)
4 A1 --- n_[FBA2002] [*] * indicates two identifications proposed
5- 9 F5.1 mas plx Tycho (I/239) parallax
11- 14 F4.1 mas e_plx rms uncertainty on plx
16- 21 F6.2 pc Dist Derived distance
23 A1 --- l_VMAG Limit flag on VMAG
24- 28 F5.2 mag VMAG Derived absolute V magnitude
30- 38 A9 --- SpType MK spectral type
40- 45 F6.1 mas/yr pmRA ? Proper motion in right ascension
47- 51 F5.2 mas/yr e_pmRA ? rms uncertainty on pmRA
53- 59 F7.2 mas/yr pmDE ? Proper motion in declination
61- 65 F5.2 mas/yr e_pmDE ? rms uncertainty on pmDE
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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- 3 I3 --- [FBA2002] Identification (sequential number)
5- 10 A6 --- SpType MK spectral type
13- 16 F4.1 mag Vmag Visual magnitude
18- 22 F5.1 mas plx Parallax
24- 27 F4.1 mas e_plx rms uncertainty on plx
29- 32 F4.1 mag E(UV) UV-excess
34- 45 A12 --- Class New classification
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History:
* 17-Jun-2002: From electronic version of the journal
* 25-Feb-2006: two corrections were made on positions in table 2:
11 17 37 39.10 -17 49 76.1 modified into 17 37 39.10 -17 49 37.1
179 17 19 23.00 -20 46 172.0 modified into 17 19 23.00 -20 46 17.2
* 25-Sep-2006: four corrections was made on position in table 2:
63 17 19 40.66 -17 39 23.4 modified into 17 22 35.34 -17 42 12.9
68 17 26 30.67 -18 37 31.5 modified into 17 29 26.70 -18 39 51.2
102 17 16 06.00 -18 31 00.0 modified into 17 19 11.78 -18 30 58.5
141 17 25 31.77 -20 19 10.2 modified into 17 25 02.60 -20 21 44.3
These corrections are based on the Simbad position of the
Proposed star identification.
(End) James Marcout, Patricia Bauer [CDS] 17-Jun-2002