J/A+A/445/69 JHK' photometry of C stars in NGC 147 (Sohn+, 2006)
Near-IR photometry of asymptotic giant branch stars in the dwarf elliptical
galaxy NGC 147.
Sohn Y.J., Kang A., Rhee J., Shin M., Chun M.S., Kim H.I.
<Astron. Astrophys. 445, 69 (2006)>
=2006A&A...445...69S 2006A&A...445...69S
ADC_Keywords: Galaxies, nearby ; Photometry, infrared ; Stars, carbon ;
Stars, giant
Keywords: galaxies: individual: NGC 147 - galaxies: stellar content -
stars: AGB and post-AGB
Abstract:
Near-infrared J, H and K' images were used to investigate the stellar
contents of the asymptotic giant branch (AGB) population in the nearby
dwarf elliptical galaxy NGC 147. The obtained (K,J-K) and (K,H-K)
color-magnitude diagrams contain stars of AGB and red giant branch
populations, where the former consists of a group of bright blue
stars, a dominant population of M giant and a red C star population.We
identified 91 AGB C stars in NGC 147 with the mean absolute magnitude
and colors of <MK≥-7.56, <(J-K)0≥1.81 and <(H-K)0≥0.74. The
estimated number ratio of C stars to M giant stars (C/M) is
0.16±0.02. The estimated local C/M ratios of 0.14±0.02 for the
inner region (r<70") and 0.19±0.03 for the outer region (r>70")
indicate a weak radial gradient. The mean bolometric magnitude of 91 C
stars in NGC 147 is <Mbol≥-4.32±0.49. The bolometric luminosity
function of M giant stars in NGC 147 extends up to Mbol=-5.8
magnitude, and that of only C stars spans -5.6<Mbol←3.5. The color
histograms of AGB stars in (J-K) and (H-K) show a main peak containing
M giant stars, a red tail containing C stars with a weak excess, and a
blue excess possibly due to bright blue foreground stars and AGB stars
younger than M giants. The comparison of the theoretical isochrone
models with the color distribution and the brightness of AGB stars
indicates that most of the bright M giants in NGC 147 were formed at
log(tyr)∼8.4 with a range of 8.2∼8.6. Ages of the majority of M
giant stars in NGC 147 are similar to those of younger M giant stars
in its companion NGC 185, while their formation occurred more recently
than the older M giant stars in NGC 185 by ∼2Gyrs.
Description:
The equatorial coordinates, near-infrared photometric properties of 91
C stars, and color indices in VRI bands of cross-identified C stars
with Nowotny et al. (2003, Cat. J/A+A/403/93) and Battinelli &
Demers (2004, Cat. J/A+A/418/33).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 82 91 Coordinates and near-IR photometric properties
for 91 C stars
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See also:
J/A+A/403/93 : Photometry of AGB stars in NGC 185 and NGC 147 (Nowotny+, 2003)
J/A+A/418/33 : RI photometry of C stars in NGC 147 (Battinelli+, 2004)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq ID number of C star
4- 5 I2 h RAh Right Ascension J2000 (hours)
7- 8 I2 min RAm Right Ascension J2000 (minutes)
10- 14 F5.2 s RAs Right Ascension J2000 (seconds)
16 A1 --- DE- Declination J2000 (sign)
17- 18 I2 deg DEd Declination J2000 (degrees)
20- 21 I2 arcmin DEm Declination J2000 (minutes)
23- 26 F4.1 arcsec DEs Declination J2000 (seconds)
28- 33 F6.3 mag K'mag K' band (2.12um) magnitude of C star
35- 39 F5.3 mag e_K'mag Error of K magnitude
41- 45 F5.3 mag (J-K') (J-K') color index
47- 51 F5.3 mag e_(J-K') Error of (J-K') color index
53- 57 F5.3 mag (H-K') (H-K') color index
59- 63 F5.3 mag e_(H-K') Error of (H-K') color index
65- 68 F4.2 mag (V-i)0 ? (V-i) color index by Nowotny et al., 2003,
Cat. J/A+A/403/93
70- 72 I3 --- Nowotny ? ID number of Nowotny et al., 2003,
Cat. J/A+A/403/93, recno number in Vizir
74- 78 F5.3 mag R-I ? (R-I) color index by Battinelli & Demers,
2004, Cat. J/A+A/418/33
80- 82 I3 --- [BD2004c] ? ID number of Battinelli & Demers, 2004,
Cat. J/A+A/418/33
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Acknowledgements: Aram Kang, breeze82(at)galaxy.yonsei.ac.kr
(End) Patricia Vannier [CDS] 06-Sep-2005