- Jung, M.Y.
- 韓國宇宙科學會誌 = Journal of astronomy & space sciences
- 26, n.4
- pp.421-424
- 2009
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The <TEX>$JHK_S$</TEX> magnitudes of the red giant branch tip (TRGB) and the distance moduli of the nearby dwarf irregular galaxy IC 1613 have been determined from the near-infrared luminosity functions (LFs) of the resolved stars in the galaxy. Applying a Savitzky-Golay filtering, we derived the second derivatives of the LFs, and estimated the apparent magnitudes of the TRGB as <TEX>$m_J\;=\;19.1$</TEX>, <TEX>$m_H\;=\;18.4$</TEX>, and <TEX>$m_{Ks}\;=\;18.0$</TEX>. The mean values of the theoretical absolute magnitudes of the TRGB were measured by using the Yonsei-Yale isochrones with a metallicity range of -2.1 < [Fe/H] < -0.5 and age of 12 Gyr. The derived values of near-infrared TRGB distance moduli for IC 1613 are (m - M) = <TEX>$24.12{\pm}0.25$</TEX>, <TEX>$24.20{\pm}0.44$</TEX>, and <TEX>$24.00{\pm}0.52$</TEX> for J, H, and <TEX>$K_S$</TEX> bands, respectively.