Stellar populations of the dwarf galaxy UKS 2323-326 in the sculptor group

Myung Gyoon Lee, Yong-Ik Byun

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy UKS 2323-326 in the Sculptor Group. The color-magnitude diagrams of the measured stars in UKS 2323-326 show a blue plume that consists mostly of young stellar populations and a well-defined red giant branch (RGB). The tip of the RGB is found to be at ITRGB = 22.65 ± 0.10 mag. From this, the distance to this galaxy is estimated to be d = 2.08 ± 0.12 Mpc. The corresponding distance of this galaxy from the center of the Local Group is 1.92 Mpc, showing that it is located outside the Local Group. The large distance, combined with its velocity information, indicates that it is very likely a member of the Sculptor Group. The mean metallicity of the RGB is estimated to be [Fe/H] = -1.98 ± 0.17 dex. The total magnitudes of UKS 2323-326 (<rH[=70″]) are derived to be BT = 14.07, VT = 13.50, RT = 13.18, and IT = 12.83 mag, and the corresponding absolute magnitudes are MB = -12.58, MV = -13.14, MR = -13.45, and MI = - 13.79 mag. Surface brightness profiles of the central part of UKS 2323-326 are approximately consistent with a King model with a core concentration parameter c = log (rt/rc) ≈ 1.0, and those of the outer part follow an exponential law with a scale length of 21″. The magnitudes and colors of the brightest blue and red stars in UKS 2323-326 (BSG and RSG) are measured to be, respectively, <V(3)>BSG = 20.33 ± 0.25, <(B - V)(3)>BSG = 0.14 ± 0.07, <V(3)>RSG = 20.74 ± 0.18, and <(B - V)(3)>RSG = 1.35 ± 0.08 mag. The corresponding absolute magnitudes are derived to be <MV(3)>BSG = -6.31 and <MV(3)>RSG = - 5.91 mag, which are about a half-magnitude fainter than those expected from conventional correlations with galaxy luminosity.

Original languageEnglish
Pages (from-to)817-825
Number of pages9
JournalAstronomical Journal
Volume118
Issue number2
DOIs
Publication statusPublished - 1999 Jan 1

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dwarf galaxies
galaxies
irregular galaxies
stars
color-magnitude diagram
young population
metallicity
plumes
photometry
charge coupled devices
luminosity
plume
diagram

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

@article{eb0f7d18282541329121a3bf77141274,
title = "Stellar populations of the dwarf galaxy UKS 2323-326 in the sculptor group",
abstract = "We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy UKS 2323-326 in the Sculptor Group. The color-magnitude diagrams of the measured stars in UKS 2323-326 show a blue plume that consists mostly of young stellar populations and a well-defined red giant branch (RGB). The tip of the RGB is found to be at ITRGB = 22.65 ± 0.10 mag. From this, the distance to this galaxy is estimated to be d = 2.08 ± 0.12 Mpc. The corresponding distance of this galaxy from the center of the Local Group is 1.92 Mpc, showing that it is located outside the Local Group. The large distance, combined with its velocity information, indicates that it is very likely a member of the Sculptor Group. The mean metallicity of the RGB is estimated to be [Fe/H] = -1.98 ± 0.17 dex. The total magnitudes of UKS 2323-326 (H[=70″]) are derived to be BT = 14.07, VT = 13.50, RT = 13.18, and IT = 12.83 mag, and the corresponding absolute magnitudes are MB = -12.58, MV = -13.14, MR = -13.45, and MI = - 13.79 mag. Surface brightness profiles of the central part of UKS 2323-326 are approximately consistent with a King model with a core concentration parameter c = log (rt/rc) ≈ 1.0, and those of the outer part follow an exponential law with a scale length of 21″. The magnitudes and colors of the brightest blue and red stars in UKS 2323-326 (BSG and RSG) are measured to be, respectively, <V(3)>BSG = 20.33 ± 0.25, <(B - V)(3)>BSG = 0.14 ± 0.07, <V(3)>RSG = 20.74 ± 0.18, and <(B - V)(3)>RSG = 1.35 ± 0.08 mag. The corresponding absolute magnitudes are derived to be <MV(3)>BSG = -6.31 and <MV(3)>RSG = - 5.91 mag, which are about a half-magnitude fainter than those expected from conventional correlations with galaxy luminosity.",
author = "Lee, {Myung Gyoon} and Yong-Ik Byun",
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Stellar populations of the dwarf galaxy UKS 2323-326 in the sculptor group. / Lee, Myung Gyoon; Byun, Yong-Ik.

In: Astronomical Journal, Vol. 118, No. 2, 01.01.1999, p. 817-825.

Research output: Contribution to journalArticle

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N2 - We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy UKS 2323-326 in the Sculptor Group. The color-magnitude diagrams of the measured stars in UKS 2323-326 show a blue plume that consists mostly of young stellar populations and a well-defined red giant branch (RGB). The tip of the RGB is found to be at ITRGB = 22.65 ± 0.10 mag. From this, the distance to this galaxy is estimated to be d = 2.08 ± 0.12 Mpc. The corresponding distance of this galaxy from the center of the Local Group is 1.92 Mpc, showing that it is located outside the Local Group. The large distance, combined with its velocity information, indicates that it is very likely a member of the Sculptor Group. The mean metallicity of the RGB is estimated to be [Fe/H] = -1.98 ± 0.17 dex. The total magnitudes of UKS 2323-326 (H[=70″]) are derived to be BT = 14.07, VT = 13.50, RT = 13.18, and IT = 12.83 mag, and the corresponding absolute magnitudes are MB = -12.58, MV = -13.14, MR = -13.45, and MI = - 13.79 mag. Surface brightness profiles of the central part of UKS 2323-326 are approximately consistent with a King model with a core concentration parameter c = log (rt/rc) ≈ 1.0, and those of the outer part follow an exponential law with a scale length of 21″. The magnitudes and colors of the brightest blue and red stars in UKS 2323-326 (BSG and RSG) are measured to be, respectively, <V(3)>BSG = 20.33 ± 0.25, <(B - V)(3)>BSG = 0.14 ± 0.07, <V(3)>RSG = 20.74 ± 0.18, and <(B - V)(3)>RSG = 1.35 ± 0.08 mag. The corresponding absolute magnitudes are derived to be <MV(3)>BSG = -6.31 and <MV(3)>RSG = - 5.91 mag, which are about a half-magnitude fainter than those expected from conventional correlations with galaxy luminosity.

AB - We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy UKS 2323-326 in the Sculptor Group. The color-magnitude diagrams of the measured stars in UKS 2323-326 show a blue plume that consists mostly of young stellar populations and a well-defined red giant branch (RGB). The tip of the RGB is found to be at ITRGB = 22.65 ± 0.10 mag. From this, the distance to this galaxy is estimated to be d = 2.08 ± 0.12 Mpc. The corresponding distance of this galaxy from the center of the Local Group is 1.92 Mpc, showing that it is located outside the Local Group. The large distance, combined with its velocity information, indicates that it is very likely a member of the Sculptor Group. The mean metallicity of the RGB is estimated to be [Fe/H] = -1.98 ± 0.17 dex. The total magnitudes of UKS 2323-326 (H[=70″]) are derived to be BT = 14.07, VT = 13.50, RT = 13.18, and IT = 12.83 mag, and the corresponding absolute magnitudes are MB = -12.58, MV = -13.14, MR = -13.45, and MI = - 13.79 mag. Surface brightness profiles of the central part of UKS 2323-326 are approximately consistent with a King model with a core concentration parameter c = log (rt/rc) ≈ 1.0, and those of the outer part follow an exponential law with a scale length of 21″. The magnitudes and colors of the brightest blue and red stars in UKS 2323-326 (BSG and RSG) are measured to be, respectively, <V(3)>BSG = 20.33 ± 0.25, <(B - V)(3)>BSG = 0.14 ± 0.07, <V(3)>RSG = 20.74 ± 0.18, and <(B - V)(3)>RSG = 1.35 ± 0.08 mag. The corresponding absolute magnitudes are derived to be <MV(3)>BSG = -6.31 and <MV(3)>RSG = - 5.91 mag, which are about a half-magnitude fainter than those expected from conventional correlations with galaxy luminosity.

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