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J/A+A/454/717   Near-IR photometry of C and AGB stars in NGC 6822 (Kang+, 2006)

The evolved asymptotic giant branch stars in the central bar of the dwarf irregular galaxy NGC 6822. Kang A., Sohn Y.-J., Kim H.-I., Rhee J., Kim J.-W., Hwang N., Lee M.G, Kim Y.-C., Chun M.-S. <Astron. Astrophys. 464, 717 (2006)> =2006A&A...454..717K
ADC_Keywords: Galaxies, photometry ; Stars, giant ; Stars, carbon ; Photometry, infrared Keywords: galaxies: individual: NGC 6822 - galaxies: stellar content - stars: AGB and post-AGB Abstract: Images of JHK and gi obtained with the Canada-France-Hawaii Telescope are used to investigate the stellar contents of the resolved asymptotic giant branch (AGB) population in the area of 3.6'x6.3' on the central bar of the dwarf irregular galaxy NGC 6822. The upper envelope of near-infrared (J-K, K) and (H-K, K) color-magnitude diagrams (CMDs) shows four components of main-sequence stars, foreground stars, massive supergiants, and AGB stars. These components are also noticeable in the bright part of (g-i, g) CMD. We select AGB stars in NGC 6822 from the (g-K, g) CMD, which has a long spectral wavelength base line in the color index. There are 141 C stars with a mean absolute magnitude of <MK≥-7.60±0.50, and with mean colors of <(J-K)o≥1.77±0.41, and <(H-K)o≥0.75±0.28. The number ratio of C stars to M-giants (C/M) is estimated as 0.27±0.03, while the northern part of the bar has a somewhat lower C/M ratio than the southern part. The (J-K) and (H-K) color distributions of AGB stars contain a main peak of M-giant stars and a red tail of C stars. The broad color distributions for M-giants indicate that NGC 6822 has a wide range of intermediate ages with a peak at log(tyr)∼9.0. The MK luminosity function (LF) for C stars in the central bar of NGC 6822 is likely to be a Gaussian distribution, while the LF of C stars in the southern part is slightly skewed to the brighter side than in northern part. The mean bolometric magnitude of 141 C stars in NGC 6822 is <Mbol≥-4.36±0.54. The bolometric LF for M-giants extends up to Mbol=-6.5, while the one for C stars spans -5.8<Mbol←3.5. Description: Table 2 lists the equatorial coordinates, near-infrared photometric properties of 141 C stars, and color indices in RI bands of cross-identified C stars with Letarte et al. (2002, Cat. J/AJ/123/832). Table 3 lists those of the rest 522 M-giants of AGB stars. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 108 141 Coordinates and photometric properties for 141 C stars table3.dat 108 522 Coordinates and photometric properties for 522 M-giant stars
See also: J/AJ/123/832 : C star population in NGC 6822 (Letarte+, 2002) Byte-by-byte Description of file: table2.dat table3.dat
Bytes Format Units Label Explanations
2- 4 I3 --- Seq [1/522] Sequential number of C star (table2) or M-giant star (table3) 7- 8 I2 h RAh Right Ascension J2000 (hours) 10- 11 I2 min RAm Right Ascension J2000 (minutes) 13- 17 F5.2 s RAs Right Ascension J2000 (seconds) 19 A1 --- DE- Declination J2000 (sign) 20- 21 I2 deg DEd Declination J2000 (degrees) 23- 24 I2 arcmin DEm Declination J2000 (minutes) 26- 29 F4.1 arcsec DEs Declination J2000 (seconds) 32- 37 F6.3 mag Kmag K band magnitude 39- 43 F5.3 mag e_Kmag Error of K magnitude 46- 50 F5.3 mag J-K (J-K) color index 52- 56 F5.3 mag e_J-K Error of (J-K) color index 59- 63 F5.3 mag H-K (H-K) color index 65- 69 F5.3 mag e_H-K Error of (H-K) color index 72- 77 F6.3 mag gmag g band magnitude 79- 83 F5.3 mag e_gmag Error of g magnitude 85- 90 F6.3 mag g-i (g-i) color index 92- 96 F5.3 mag e_g-i Error of (g-i) color index 99-103 F5.3 mag R-I ? (R-I) color index by Letarte et al., 2002, Cat. J/AJ/123/832 (1) 106-108 I3 --- [LDB2002] ? ID number of Letarte et al., 2002, Cat. J/AJ/123/832 (1)
Note (1): Only for table2.dat objects.
Acknowledgements: Aram Kang, breeze82(at)
(End) Patricia Vannier [CDS] 16-Mar-2006
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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