Near-IR photometry of asymptotic giant branch stars in the dwarf elliptical galaxy NGC 185

A. Kang, Y. J. Sohn, J. Rhee, M. Shin, M. S. Chun, Ho Il Kim

Research output: Contribution to journalArticle

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Abstract

J, H and K' images obtained with the Canada-France-Hawaii Telescope were used to investigate the stellar contents of the asymptotic giant branch (AGB) in the dwarf elliptical galaxy NGC 185. The bright parts of (K, J - K) and (K, H - K) color-magnitude diagrams consist of a group of bright blue stars, a dominant population of M-giants and a red C star population. There were 73 C stars with a mean magnitude of (K) = 16.26 ± 0.38, corresponding to (MK) = -7.93, and mean colors of ((J - K)0) = 2.253 and 〈(H - K) 0〉 = 0.865. The number ratio of C stars to M-giants was estimated to be 0.11 ± 0.04 without any radial gradient from the center of NGC 185. The (J - K) and (H - K) color distributions of AGB stars showed an M-giant peak and blue and red tails, where the latter two correspond to AGB stars younger than those along M-giant peak and C stars. The bolometric luminosity functions of M-giants and C stars indicate that the M-giant AGB sequence has terminated at Mb01 = -6.2, while the most luminous C star has Mbol = -5.5. The bolometric luminosity function of C stars in NGC 185 is very similar to that of recent literature values derived from Vi band photometry. The logarithmic slope of the luminosity function for bright M-giant stars was estimated to be 0.83 ± 0.02 in K band. Theoretical isochrone models, compared with the observed near-infrared photometric properties of AGB stars, indicate that star formation in NGC 185 has a wide range of ages with possibly two different epochs of star formation.

Original languageEnglish
Pages (from-to)61-68
Number of pages8
JournalAstronomy and Astrophysics
Volume437
Issue number1
DOIs
Publication statusPublished - 2005 Jan 1

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carbon stars
asymptotic giant branch stars
elliptical galaxies
dwarf galaxies
photometry
giant stars
M stars
luminosity
near infrared
diagram
star formation
color
blue stars
color-magnitude diagram
extremely high frequencies
France
Canada
time measurement
telescopes
slopes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Kang, A. ; Sohn, Y. J. ; Rhee, J. ; Shin, M. ; Chun, M. S. ; Kim, Ho Il. / Near-IR photometry of asymptotic giant branch stars in the dwarf elliptical galaxy NGC 185. In: Astronomy and Astrophysics. 2005 ; Vol. 437, No. 1. pp. 61-68.
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abstract = "J, H and K' images obtained with the Canada-France-Hawaii Telescope were used to investigate the stellar contents of the asymptotic giant branch (AGB) in the dwarf elliptical galaxy NGC 185. The bright parts of (K, J - K) and (K, H - K) color-magnitude diagrams consist of a group of bright blue stars, a dominant population of M-giants and a red C star population. There were 73 C stars with a mean magnitude of (K) = 16.26 ± 0.38, corresponding to (MK) = -7.93, and mean colors of ((J - K)0) = 2.253 and 〈(H - K) 0〉 = 0.865. The number ratio of C stars to M-giants was estimated to be 0.11 ± 0.04 without any radial gradient from the center of NGC 185. The (J - K) and (H - K) color distributions of AGB stars showed an M-giant peak and blue and red tails, where the latter two correspond to AGB stars younger than those along M-giant peak and C stars. The bolometric luminosity functions of M-giants and C stars indicate that the M-giant AGB sequence has terminated at Mb01 = -6.2, while the most luminous C star has Mbol = -5.5. The bolometric luminosity function of C stars in NGC 185 is very similar to that of recent literature values derived from Vi band photometry. The logarithmic slope of the luminosity function for bright M-giant stars was estimated to be 0.83 ± 0.02 in K band. Theoretical isochrone models, compared with the observed near-infrared photometric properties of AGB stars, indicate that star formation in NGC 185 has a wide range of ages with possibly two different epochs of star formation.",
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Near-IR photometry of asymptotic giant branch stars in the dwarf elliptical galaxy NGC 185. / Kang, A.; Sohn, Y. J.; Rhee, J.; Shin, M.; Chun, M. S.; Kim, Ho Il.

In: Astronomy and Astrophysics, Vol. 437, No. 1, 01.01.2005, p. 61-68.

Research output: Contribution to journalArticle

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T1 - Near-IR photometry of asymptotic giant branch stars in the dwarf elliptical galaxy NGC 185

AU - Kang, A.

AU - Sohn, Y. J.

AU - Rhee, J.

AU - Shin, M.

AU - Chun, M. S.

AU - Kim, Ho Il

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N2 - J, H and K' images obtained with the Canada-France-Hawaii Telescope were used to investigate the stellar contents of the asymptotic giant branch (AGB) in the dwarf elliptical galaxy NGC 185. The bright parts of (K, J - K) and (K, H - K) color-magnitude diagrams consist of a group of bright blue stars, a dominant population of M-giants and a red C star population. There were 73 C stars with a mean magnitude of (K) = 16.26 ± 0.38, corresponding to (MK) = -7.93, and mean colors of ((J - K)0) = 2.253 and 〈(H - K) 0〉 = 0.865. The number ratio of C stars to M-giants was estimated to be 0.11 ± 0.04 without any radial gradient from the center of NGC 185. The (J - K) and (H - K) color distributions of AGB stars showed an M-giant peak and blue and red tails, where the latter two correspond to AGB stars younger than those along M-giant peak and C stars. The bolometric luminosity functions of M-giants and C stars indicate that the M-giant AGB sequence has terminated at Mb01 = -6.2, while the most luminous C star has Mbol = -5.5. The bolometric luminosity function of C stars in NGC 185 is very similar to that of recent literature values derived from Vi band photometry. The logarithmic slope of the luminosity function for bright M-giant stars was estimated to be 0.83 ± 0.02 in K band. Theoretical isochrone models, compared with the observed near-infrared photometric properties of AGB stars, indicate that star formation in NGC 185 has a wide range of ages with possibly two different epochs of star formation.

AB - J, H and K' images obtained with the Canada-France-Hawaii Telescope were used to investigate the stellar contents of the asymptotic giant branch (AGB) in the dwarf elliptical galaxy NGC 185. The bright parts of (K, J - K) and (K, H - K) color-magnitude diagrams consist of a group of bright blue stars, a dominant population of M-giants and a red C star population. There were 73 C stars with a mean magnitude of (K) = 16.26 ± 0.38, corresponding to (MK) = -7.93, and mean colors of ((J - K)0) = 2.253 and 〈(H - K) 0〉 = 0.865. The number ratio of C stars to M-giants was estimated to be 0.11 ± 0.04 without any radial gradient from the center of NGC 185. The (J - K) and (H - K) color distributions of AGB stars showed an M-giant peak and blue and red tails, where the latter two correspond to AGB stars younger than those along M-giant peak and C stars. The bolometric luminosity functions of M-giants and C stars indicate that the M-giant AGB sequence has terminated at Mb01 = -6.2, while the most luminous C star has Mbol = -5.5. The bolometric luminosity function of C stars in NGC 185 is very similar to that of recent literature values derived from Vi band photometry. The logarithmic slope of the luminosity function for bright M-giant stars was estimated to be 0.83 ± 0.02 in K band. Theoretical isochrone models, compared with the observed near-infrared photometric properties of AGB stars, indicate that star formation in NGC 185 has a wide range of ages with possibly two different epochs of star formation.

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