Near-infrared photometric properties of asymptotic giant branch stars in the dwarf irregular galaxy IC 1613

Sang Hyun Chun, Miyoung Jung, Minhee Kang, Jae Woo Kim, Young Jong Sohn

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Aims. We investigated the photometric properties of asymptotic giant branch (AGB) stars of the dwarf irregular galaxy IC 1613 and its metallicity. Methods. We used near-infrared JHKs photometric data obtained with the WIRCam array on Canada-France-Hawaii Telescope (CFHT). The optical gi imaging data of a previous study were cross-matched with ours to distinguish the stellar populations in the galaxy and to select the AGB stars. We also separated the C stars from the M-giant stars in the JHKs color-color diagram. Results. We identified 140 C stars and 306 M-giant stars in IC 1613. The (J - Ks) color histogram of AGB stars shows the main peak of M-giant stars and the red tail of C stars. The broad color distribution of M-giant stars and the isochrones in the color magnitude diagram indicate that IC 1613 has a wide range of intermediate-age stars. We also know that most C stars were formed over the past 2-8 Gyr according the Mbol-age relation. The C/M ratio of 0.46 ± 0.05 was estimated and [Fe/H] abundance of -1.23 ± 0.06 was derived from the C/M ratio. Radial distributions of C/M ratio and metallicity show the shallow trend of the negative metallicity gradient from the center. The local C/M ratio also indicates that the HI cavity has higher C/M values than the bright HI spot and HI gas region. However, the low [Fe/H] value near the central region of the galaxy is likely to be caused by the change in age of the dominant stellar population according to the radial distance, not the real metallicity variation. It might also be that relatively younger and metal-rich C stars are concentrated in the center of the galaxy, while the M-giant stars were homogeneously distributed from the center to the borders of the galaxy.

Original languageEnglish
Article numberA51
JournalAstronomy and Astrophysics
Volume578
DOIs
Publication statusPublished - 2015 Jun 1

Fingerprint

irregular galaxies
giant stars
carbon stars
M stars
asymptotic giant branch stars
dwarf galaxies
near infrared
metallicity
galaxies
diagram
color-color diagram
color
color-magnitude diagram
histogram
France
borders
Canada
radial distribution
histograms
cavity

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

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title = "Near-infrared photometric properties of asymptotic giant branch stars in the dwarf irregular galaxy IC 1613",
abstract = "Aims. We investigated the photometric properties of asymptotic giant branch (AGB) stars of the dwarf irregular galaxy IC 1613 and its metallicity. Methods. We used near-infrared JHKs photometric data obtained with the WIRCam array on Canada-France-Hawaii Telescope (CFHT). The optical gi imaging data of a previous study were cross-matched with ours to distinguish the stellar populations in the galaxy and to select the AGB stars. We also separated the C stars from the M-giant stars in the JHKs color-color diagram. Results. We identified 140 C stars and 306 M-giant stars in IC 1613. The (J - Ks) color histogram of AGB stars shows the main peak of M-giant stars and the red tail of C stars. The broad color distribution of M-giant stars and the isochrones in the color magnitude diagram indicate that IC 1613 has a wide range of intermediate-age stars. We also know that most C stars were formed over the past 2-8 Gyr according the Mbol-age relation. The C/M ratio of 0.46 ± 0.05 was estimated and [Fe/H] abundance of -1.23 ± 0.06 was derived from the C/M ratio. Radial distributions of C/M ratio and metallicity show the shallow trend of the negative metallicity gradient from the center. The local C/M ratio also indicates that the HI cavity has higher C/M values than the bright HI spot and HI gas region. However, the low [Fe/H] value near the central region of the galaxy is likely to be caused by the change in age of the dominant stellar population according to the radial distance, not the real metallicity variation. It might also be that relatively younger and metal-rich C stars are concentrated in the center of the galaxy, while the M-giant stars were homogeneously distributed from the center to the borders of the galaxy.",
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Near-infrared photometric properties of asymptotic giant branch stars in the dwarf irregular galaxy IC 1613. / Chun, Sang Hyun; Jung, Miyoung; Kang, Minhee; Kim, Jae Woo; Sohn, Young Jong.

In: Astronomy and Astrophysics, Vol. 578, A51, 01.06.2015.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Near-infrared photometric properties of asymptotic giant branch stars in the dwarf irregular galaxy IC 1613

AU - Chun, Sang Hyun

AU - Jung, Miyoung

AU - Kang, Minhee

AU - Kim, Jae Woo

AU - Sohn, Young Jong

PY - 2015/6/1

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N2 - Aims. We investigated the photometric properties of asymptotic giant branch (AGB) stars of the dwarf irregular galaxy IC 1613 and its metallicity. Methods. We used near-infrared JHKs photometric data obtained with the WIRCam array on Canada-France-Hawaii Telescope (CFHT). The optical gi imaging data of a previous study were cross-matched with ours to distinguish the stellar populations in the galaxy and to select the AGB stars. We also separated the C stars from the M-giant stars in the JHKs color-color diagram. Results. We identified 140 C stars and 306 M-giant stars in IC 1613. The (J - Ks) color histogram of AGB stars shows the main peak of M-giant stars and the red tail of C stars. The broad color distribution of M-giant stars and the isochrones in the color magnitude diagram indicate that IC 1613 has a wide range of intermediate-age stars. We also know that most C stars were formed over the past 2-8 Gyr according the Mbol-age relation. The C/M ratio of 0.46 ± 0.05 was estimated and [Fe/H] abundance of -1.23 ± 0.06 was derived from the C/M ratio. Radial distributions of C/M ratio and metallicity show the shallow trend of the negative metallicity gradient from the center. The local C/M ratio also indicates that the HI cavity has higher C/M values than the bright HI spot and HI gas region. However, the low [Fe/H] value near the central region of the galaxy is likely to be caused by the change in age of the dominant stellar population according to the radial distance, not the real metallicity variation. It might also be that relatively younger and metal-rich C stars are concentrated in the center of the galaxy, while the M-giant stars were homogeneously distributed from the center to the borders of the galaxy.

AB - Aims. We investigated the photometric properties of asymptotic giant branch (AGB) stars of the dwarf irregular galaxy IC 1613 and its metallicity. Methods. We used near-infrared JHKs photometric data obtained with the WIRCam array on Canada-France-Hawaii Telescope (CFHT). The optical gi imaging data of a previous study were cross-matched with ours to distinguish the stellar populations in the galaxy and to select the AGB stars. We also separated the C stars from the M-giant stars in the JHKs color-color diagram. Results. We identified 140 C stars and 306 M-giant stars in IC 1613. The (J - Ks) color histogram of AGB stars shows the main peak of M-giant stars and the red tail of C stars. The broad color distribution of M-giant stars and the isochrones in the color magnitude diagram indicate that IC 1613 has a wide range of intermediate-age stars. We also know that most C stars were formed over the past 2-8 Gyr according the Mbol-age relation. The C/M ratio of 0.46 ± 0.05 was estimated and [Fe/H] abundance of -1.23 ± 0.06 was derived from the C/M ratio. Radial distributions of C/M ratio and metallicity show the shallow trend of the negative metallicity gradient from the center. The local C/M ratio also indicates that the HI cavity has higher C/M values than the bright HI spot and HI gas region. However, the low [Fe/H] value near the central region of the galaxy is likely to be caused by the change in age of the dominant stellar population according to the radial distance, not the real metallicity variation. It might also be that relatively younger and metal-rich C stars are concentrated in the center of the galaxy, while the M-giant stars were homogeneously distributed from the center to the borders of the galaxy.

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