The First MAXI/GSC Catalog in the High Galactic-Latitude Sky
Isobe, Naoki; Yamaoka, Kazutaka; Nakagawa, Yujin E.; Yoshida, Atsumasa; Ueda, Yoshihiro; Kawai, Nobuyuki; Shidatsu, Megumi; Tomida, Hiroshi; Tsuboi, Yohko; Tsunemi, Hiroshi; Kimura, Masashi; Mihara, Tatehiro; Nakajima, Motoki; Sugizaki, Mutsumi; Morii, Mikio; Hiroi, Kazuo; Hayashida, Masaaki; Eguchi, Satoshi; Matsuoka, Masaru; Ishikawa, Masaki; Kitayama, Hiroki; Kohama, Mitsuhiro; Matsumura, Takanori; Nakahira, Satoshi; Negoro, Hitoshi; Serino, Motoko; Sootome, Tetsuya; Sugimori, Kousuke; Suwa, Fumitoshi; Toizumi, Takahiro; Ueno, Shiro; Usui, Ryuichi; Yamamoto, Takayuki; Yamazaki, Kyohei
Japan
Abstract
We present the first unbiased source catalog of the Monitor of All-sky X-ray Image (MAXI) mission at high Galactic latitudes ( $\vert b\vert$$>$ 10 $^{\circ}$ ), produced from the first 7-month data (2009 September 1 to 2010 March 31) of the Gas Slit Camera in the 4-10 keV band. We have developed an analysis procedure to detect faint sources from the MAXI data, utilizing a maximum likelihood image fitting method, where the image response, background, and detailed observational conditions are taken into account. The catalog consists of 143 X-ray sources above the 7 $\sigma$ significance level with a limiting sensitivity of $\sim\ $ 1.5 $\times$ 10 $^{-11}\ $ erg cm $^{-2}\ $ s $^{-1}$ (1.2 mCrab) in the 4-10 keV band. Among them, we have identified 38 Galactic/LMC/SMC objects, 48 galaxy clusters, 39 Seyfert galaxies, 12 blazars, and 1 galaxy. Four other sources are confused with multiple objects, and one remains unidentified. The log $\ N$ -log $\ S$ relation of extragalactic objects is in good agreement with the HEAO-1 A-2 result, although the list of the brightest AGNs in the entire sky has significantly changed since that produced 30 yr ago.