J/A+A/543/A35 Near-IR photometry of C stars in NGC 205 (Jung+, 2012)
Near-infrared properties of asymptotic giant branch stars in nearby dwarf
elliptical galaxy NGC 205.
Jung M.Y., Ko J., Kim J.-W., Chun S.-H., Kim H.-I., Sohn Y.-J.
<Astron. Astrophys. 543, A35 (2012)>
=2012A&A...543A..35J 2012A&A...543A..35J
ADC_Keywords: Galaxies, nearby ; Stars, giant ; Stars, carbon ;
Photometry, infrared
Keywords: galaxies: individual: NGC205 - galaxies: stellar content -
stars: AGB and post-AGB
Abstract:
We investigated the distribution of resolved asymptotic giant branch
(AGB) stars over a much larger area than covered by previous
near-infrared studies in the nearby dwarf elliptical galaxy NGC 205.
Using data obtained with the WIRCam near-infrared imager of the CFHT,
we selected the AGB stars in the JHKs color - magnitude diagrams, and
separated the C stars from M-giant stars in the JHKs color - color
diagram. We identified 1,550 C stars in NGC 205 with a mean absolute
magnitude of <M_Ks≥-7.49±0.54, and colors of <(J-K)_0≥1.81±0.41
and <(H-Ks)_0≥0.76±0.24. The ratio of C stars to M-giant stars
was estimated to be 0.15±0.01 in NGC 205, and the local C/M ratios
for the southern region are somewhat lower than those for the northern
region. The (J-K) color distributions of AGB stars contain the main
peak of the M-giant stars and the red tail of the C stars. A
comparison of the theoretical isochrone models with the observed color
distribution indicates that most of the bright M-giant stars in NGC
205 were formed at log(tyr)∼9.0-9.7. The logarithmic slope of the
MKs luminosity function for M-giant stars was estimated to be
0.84±0.01, which is comparable with dwarf elliptical galaxies NGC
147 and NGC 185. Furthermore, we found that the logarithmic slopes of
the MKs luminosity function for C and M-giant stars are different to
places, implying a different star formation history within NGC 205.
The bolometric luminosity function for M-giant stars extends to
Mbol=-6.0mag, and that for C stars spans -5.6<Mbol←3.0. The
bolometric luminosity function of C stars is unlikely to be a Gaussian
distribution and the mean bolometric magnitude of C stars is estimated
to be Mbol=-4.24±0.55, which is consistent with our results for
dwarf elliptical galaxies NGC 147 and NGC 185.
Description:
Table 1 lists the equatorial coordinates, near-infrared photometric
properties of 1,550 C stars, and color indices in RI bands of
cross-identified C stars with Demers et al. (2003, Cat.
J/AJ/125/3037).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 113 1550 Coordinates and photometric properties for
1550 C stars in NGC 205
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See also:
J/AJ/125/3037 : RI photometry of NGC 205 carbon stars (Demers+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID ID number of C star
7 I1 h RAh Right Ascension J2000 (hours)
9- 10 I2 min RAm Right Ascension J2000 (minutes)
12- 16 F5.2 s RAs Right Ascension J2000 (seconds)
18 A1 --- DE- Declination J2000 (sign)
19- 20 I2 deg DEd Declination J2000 (degrees)
22- 23 I2 arcmin DEm Declination J2000 (minutes)
25- 28 F4.1 arcsec DEs Declination J2000 (seconds)
31- 36 F6.3 mag Ksmag Ks band magnitude of C star
38- 42 F5.3 mag e_Ksmag Error of Ks magnitude
45- 49 F5.3 mag J-Ks J-Ks color index
51- 55 F5.3 mag e_J-Ks Error of J-Ks color index
58- 62 F5.3 mag H-Ks H-Ks color index
64- 68 F5.3 mag e_H-Ks Error of H-Ks color index
71- 76 F6.3 mag Imag ? I band magnitude of C star (1)
78- 82 F5.3 mag e_Imag ? Error of I magnitude (1)
85- 89 F5.3 mag R-I ? R-I color index (1)
91- 95 F5.3 mag e_R-I ? Error of R-I color index (1)
98-102 F5.3 mag CN-TiO ? CN-TiO color index (1)
104-108 F5.3 mag e_CN-TiO ? Error of CN-TiO color index (1)
111-113 I3 --- [DBL2003] ? ID number of Demers et al., 2003,
Cat. J/AJ/125/3037
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Note (1): From Demers et al., 2003, Cat. J/AJ/125/3037
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Acknowledgements:
MiYoung Jung, myjung(at)galaxy.yonsei.ac.kr
(End) Patricia Vannier [CDS] 25-Jul-2012