J/A+A/537/A108 NGC 6822 AGB spectroscopic catalogue (Kacharov+, 2012)
Spectra probing the number ratio between C- and M-type AGB stars in the
NGC 6822 galaxy.
Kacharov N., Rejkuba M., Cioni M.-R. L.
<Astron. Astrophys. 537, A108 (2012)>
=2012A&A...537A.108K 2012A&A...537A.108K
ADC_Keywords: Galaxies, photometry ; Stars, giant ; Stars, carbon ; Spectroscopy
Keywords: stars: AGB and post-AGB - galaxies: dwarf -
galaxies: stellar content - Local Group - galaxies: irregular -
galaxies: individual: NGC 6822
Abstract:
We calibrate spectroscopically the C- versus (vs.) M-type asymptotic
giant branch (AGB) star selection made using near-IR photometry, and
investigate the spatial distribution of the C/M ratio in NGC 6822,
based on low resolution spectroscopy and near-IR photometry.
Description:
We present a spectrophotometric catalogue of more than 500 objects
towards the direction of NGC 6822, for which we have obtained good
quality spectra. The catalogue is in table2. It contains information
for 122 M-type giants, 150 C-type giants, 9 S-type giants (genuine NGC
6822 AGB stars) and 226 foreground M- and K-type dwarfs. The spectrum
for each star is presented in the subdirectory sp. Index 'a' or 'b'
in the title means that two spectra exist for the same star.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 102 546 Spectrophotometric catalogue for 542 stars
sp/* . 546 Individual spectra
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See also:
J/A+A/454/717 : Near-IR photometry of C and AGB stars in NGC 6822 (Kang+, 2006)
J/A+A/456/905 : JKs, i'g'r' photometry of C stars in NGC 6822 (Demers+, 2006)
J/AJ/123/832 : C star population in NGC 6822 (Letarte+, 2002)
J/AJ/132/378 : HST and UV photometry of NGC 6822 (Bianchi+, 2006)
J/AJ/132/1372 : Chandra observation of NGC 6822 (Tennant+, 2006)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- Seq Stellar sequential number
8- 15 F8.3 pix Xpos X position in the pre-imaging frame
17- 24 F8.3 pix Ypos Y position in the pre-imaging frame
26- 35 F10.6 deg RAdeg Right ascension (J2000) (1)
37- 46 F10.6 deg DEdeg Declination (J2000) (1)
48- 57 F10.8 deg Dist Radial distance from galaxy centre
59- 64 F6.3 mag Rmag R band magnitude
66- 71 F6.3 mag Jmag J band magnitude (1)
73- 78 F6.3 mag Hmag H band magnitude (1)
80- 85 F6.3 mag Kmag K band magnitude (1)
87- 89 A3 --- SpTph Spectral type assigned through photometry (1)
91- 98 A8 --- SpType Spectral type assigned through spectroscopy
100 I1 --- q_SpType [4/6] Quality flag, 6=excellent (2)
102 A1 --- Nsp [1/2] Number of spectra for this star
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Note (1): Coordinates, JHK photometry and Phot column are from the work of
Sibbons et al. (2011) in preparation.
Note (2): poor quality (2 or 3 were excluded). Values used here:
4 = we can determine whether the star is M- or C-type and eventually
whether it is a giant or a foreground dwarf;
5 = very good quality spectra, the error in the spectral classification
is within ±1 subtype;
6 = excellent quality and precise determination of the spectral class.
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 4 I4 pix Pix Pixel number
7- 13 F7.2 0.1nm lambda Wavelength (Angstroms)
15- 23 F9.6 aW/m2/nm Flux Original flux (1)
25- 33 F9.6 aW/m2/nm FluxS Flux smoothed by level 5 boxcar (1)
34- 43 F10.6 --- FluxN Smoothed flux normalized at 6100Å
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Note (1): the spectral flux density is expressed in
10-16erg/cm2/s/Å = 10-18W/m2/nm
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Acknowledgements:
Nikolay Kacharov, kacni(at)abv.bg
History:
* 03-Nov-2011: Original version
* 06-Mar-2012: K-magnitudes fixed (all between 10 and 20)
(End) Nikolay Kacharov [IA, BAS, Bulgaria], Patricia Vannier [CDS] 03-Nov-2011