J/A+A/405/531 IR spectra of ISOGAL sources in Galactic Bulge (Schultheis+, 2003)
Near-IR spectra of ISOGAL sources in the inner Galactic Bulge.
Schultheis M., Lancon A., Omont A., Schuller F., Ojha D.K.
<Astron. Astrophys. 405, 531 (2003)>
=2003A&A...405..531S 2003A&A...405..531S
ADC_Keywords: Infrared sources ; Spectra, infrared ; Photometry, infrared ;
Equivalent widths
Keywords: infrared: stars - ISM: dust, extinction - Galaxy: bulge -
stars: AGB and post-AGB
Abstract:
In this work we present near-IR spectra (HK-band) of a sample of 107
sources with mid-IR excesses at 7 and 15µm detected during the
ISOGAL survey. Making use of the DENIS interstellar extinction map
from Schultheis et al. (1999, Cat. J/A+A/349/L69) we derive
luminosities and find that the Mbol vs. 12CO and Mbol vs. H2O
diagrams are powerful tools for identifying supergiants, AGB stars,
giants and young stellar objects. The majority of our sample are AGB
stars (∼80%) while we find four good supergiant candidates, nine young
stellar objects and 12 RGB candidates. We have used the most recent
K0-[15] relation by Jeong et al. (2002, in Mass-losing Pulsating
tars and their Circumstellar Matter, ed. Y. Nakasa, M. Honma, & M.
Sekiin) based on recent theoretical modeling of dust formation of AGB
stars to determine mass-loss rates. The mass-loss rates of the
supergiants are comparable with those in the solar neighbourhood while
the long-period Variables cover a mass-loss range from
-5<log(dM/dt)←7. The red giant candidates lie at the lower end of the
mass-loss rate range between -6.5<log(dM/dt)←9. We used the
equivalent width of the CO bandhead at 2.3 mum, the NaI doublet and
the CaI triplet to estimate metallicities using the relation by
Ramirez et al. (2000ApJ...537..205R 2000ApJ...537..205R). The metallicity distribution of
the ISOGAL objects shows a mean [Fe/H]~-0.25dex with a dispersion of
±0.40dex which is in agreement with the values of Ramirez et al.
(2000ApJ...537..205R 2000ApJ...537..205R) for Galactic Bulge fields between b=-4° and
b=-1.3°. A comparison with the solar neighbourhood sample of
Lancon & Wood (2000, Cat. J/A+AS/146/217) shows that our sample
is ∼0.5dex more metal-rich on average.
Description:
A table with photometric, spectroscopic parameters of the 107 spectra
are presented. For each object, the coordinates, the DENIS JK
magnitudes, the ISOGAL [7] and [15] magnitudes, the extinction Av
values, the equivalent widths of 12CO, NaI,CaI and H2O, the bolometric
magnitudes, the log of the mass-loss rates and the type of the object.
For each of the object we provide also the corresponding dereddened
spectrum as ASCII file.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 122 107 Positions, photometric and spectroscopic
indices of observed ISOGAL sources
spectra/* . 107 *ASCII file of spectra
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Note on spectra/*: The spectra are dereddened using the extinction curve by
Mathis et al. (1990ARA&A..28...37M 1990ARA&A..28...37M) and the DENIS extinction map
(Schultheis et al., 1999, Cat. J/A+A/349/L69)
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See also:
J/A+A/349/L69 : Interstellar extinction (Schultheis+, 1999)
J/A+AS/146/217 : Library of Spectra (0.5 to 2.5um) of Cool Stars (Lancon+ 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 -- Name Object name
5- 6 I2 h RAh Right ascension (J2000.0)
8- 9 I2 min RAm Right ascension (J2000.0)
11- 14 F4.1 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- 27 F4.1 arcsec DEs Declination (J2000.0)
29- 33 F5.2 mag Jmag ?=0.0 DENIS J magnitude
35- 39 F5.2 mag Kmag DENIS K magnitude
41- 45 F5.2 mag [7]mag ?=99.99 ISOGAL 7 magnitude
47- 51 F5.2 mag [15]mag ?=99.99 ISOGAL 15 magnitude
53- 57 F5.2 mag Av Absorption in V band
59- 63 F5.2 0.1nm EWCO Equivalent width of CO band
65- 69 F5.2 0.1nm EWNa Equivalent width of Na line
71- 78 F8.2 0.1nm EWCa Equivalent width of Ca line
80- 87 F8.2 0.1nm EWH2O Equivalent width of H2O band
90- 94 F5.2 mag Mbol Bolometric absolute magnitude
97-102 F6.2 [solMass/yr] log(dM/dt) Mass-loss rate
105-114 A10 --- Type Type of object
116-122 A7 --- spFile File name in "spectra" subdirectory
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Byte-by-byte Description of file: spectra/*
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Bytes Format Units Label Explanations
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8- 12 F5.3 um lambda Wavelength in micron
15- 25 F11.8 --- F/F2.28 Normalized flux (F=1 at lambda=2.28um)
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Acknowledgements: Mathias Schultheis
(End) Patricia Bauer [CDS] 07-Aug-2003