------------------------------------------------------------------------ sgrb_paper.tex PASJ,Aug_2009,61 From: "Ryu G. Syukyo" cc: ryu@cr.scphys.kyoto-u.ac.jp X-Mailer: Mew version 5.2.51 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii X-MailScanner-Information: Please contact the postmaster@aoc.nrao.edu for more information X-MailScanner: Found to be clean X-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=2.796, required 5, autolearn=disabled, MIME_BASE64_TEXT 2.80) X-MailScanner-SpamScore: ss X-MailScanner-From: ryu@cr.scphys.kyoto-u.ac.jp X-Spam-Status: No Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by dropbox.aoc.nrao.edu id n7IGKuiV013756 %astro-ph/0904.4550 %http://pasj.asj.or.jp/v61/n4/610419/610419.pdf \documentclass{pasj00} \begin{document} \Received{2009/01/26}%{yyyy/mm/dd} \Accepted{2009/04/20}%{yyyy/mm/dd} \author{Syukyo G. \textsc{Ryu}, Katsuji \textsc{Koyama},\\ Masayoshi \textsc{Nobukawa}, Ryosuke \textsc{Fukuoka}, and Takeshi Go \textsc{Tsuru}} \affil{Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502} \email{ryu@cr.scphys.kyoto-u.ac.jp} \title{An X-Ray Face-on View of the Sgr B Molecular Clouds \\ Observed with Suzaku} \KeyWords{Galaxy: center --- ISM: molecules, clouds, structure --- X-ray spectra} \maketitle \begin{abstract} We present a new methodology to derive the positions of the Sgr B molecular clouds (MCs) along the line of sight, as an application study of the Galactic center diffuse X-rays (GCDX). The GCDX is composed of hot plasma emission of about 7 keV and 1 keV temperatures, and non-thermal continuum emission including the 6.4 keV line from neutral irons. The former, the Galactic center plasma emission (GCPE), is uniformly distributed over 1 degree in longitude, while the latter is clumpy emission produced by Thomson scattering and fluorescence from MCs irradiated by external X-rays (the X-ray reflection nebula emission: XRNE). We examined the Suzaku X-ray spectra of the GCPE and XRNE near to the Sgr B MC complex, and found that the spectra suffer from two different absorptions of $N_{\rm H}$ (Abs1) $\geq 10^{23}$~H~cm$^{-2}$ and $N_{\rm H}$ (Abs2) $\simeq 6\times$10$^{22}$ ~H~cm$^{-2}$. Abs1 is proportional to the 6.4 keV-line flux, and hence is due to the MCs, while Abs2 is typical of interstellar absorption toward the Galactic center. Assuming that the GCPE plasma is spherically-extended around Sgr A* with a uniform density and the same angular distribution of the two temperature components, we quantitatively estimated the line-of-sight positions of the MCs from the flux ratio the GCPE spectrum suffered by Abs1 and that with no Abs1. The results suggest that the Sgr B MCs are located at the near side of Sgr A* in the GCPE. \end{abstract} \end{document}