Reddening and Distance of the Local Group Starburst Galaxy IC 10

• Published in: arXiv.org 2009-07
• Main Authors: Kim, Minsun, Kim, Eunhyeuk, Hwang, Narae, Lee, Myung Gyoon, Im, Myungshin, Karoji, Hiroshi, Noumaru, Junichi, and Ichi Tanaka
• Format: Article
• Language: English
• Subjects: Color-magnitude diagram; Galactic clusters; Galaxies; Globular clusters; Infrared cameras; Infrared photometry; Local group (astronomy); Metallicity; Photometry; Reflecting telescopes; Starburst galaxies; Stars & galaxies
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0907.4844

We estimate the reddening and distance of the nearest starburst galaxy IC 10 using deep near infrared \(JHK_{S}\) photometry obtained with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru telescope. We estimate the foreground reddening toward IC 10 using \(UBV\) photometry of IC 10 from the Local Group Survey, obtaining \(E(B-V)=0.52\pm 0.04\) mag. We derive the total reddening including the internal reddening, \(E(B-V)=0.98\pm 0.06\) mag, using \(UBV\) photometry of early-type stars in IC 10 and comparing \(JHK_{S}\) photometry of red giant branch stars in IC 10 and the SMC. Using the 2MASS point source catalog of 20 Galactic globular clusters, we derive a relation between the metallicity [Fe/H]\(_{CG97}\) and the slope of the red giant branch in the \(K_{S}- (J-K_{S})\) color-magnitude diagram. The mean metallicity of the red giant branch stars in IC 10 is estimated to be [Fe/H]\(_{CG97}=-1.08\pm0.28\). The magnitude of the tip of the red giant branch (TRGB) of IC 10 in the \(K_{S}\) band is measured to be \(K_{S,TRGB}=18.28\pm0.01\). Based on the TRGB method, we estimate the distance modulus of IC 10 to be \((m-M)_{0}=24.27\pm0.03{\rm (random)}\pm0.18{\rm (systematic)}\), corresponding to the distance of \(d=715\pm10\pm60\) kpc. This confirms that IC 10 is a member of the Local Group.