An X-Ray Face-On View of the Sagittarius B Molecular Clouds Observed with Suzaku

2009/04/29 by Syukyo Gando Ryu, Syukyo G. Ryu, Katsuji Koyama +4 · 44 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Astrophysics and Star Formation Studies #Emission spectrum #Flux (metallurgy) #Galactic Center #Galactic plane #Line (geometry) #Line-of-sight #Molecular cloud #Nebula #Physics #Plasma #Reflection nebula #Sagittarius A* #Spectral line #Stars #astro-ph.GA #astro-ph.HE

paper · pdf · doi:10.1093/pasj/61.4.751

published in Publications of the Astronomical Society of Japan 61(4), 751-761 (Oxford University Press) · 11 pages, 8 figures, accepted for publication in PASJ (Publications of the Astronomical Society of Japan)

arxiv created 2009/04/29 · openalex publication_date 2009/08/25 · arxiv updated 2015/05/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

Abstract We present a new methodology to derive the positions of the Sagittarius (Sgr) B molecular clouds (MCs) along the line of sight, as an application study of the Galactic center diffuse X-rays (GCDX). The GCDX are 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^∘ 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) ≥10²³H cm^-2 and N_{\rm H} (Abs2) ≃6 × 10²²H 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.

Citations

• X-Ray Reflection Nebulae with Large Equivalent Widths of the Neutral Iron Kα Line in the Sagittarius C Region
• The Position of Sagittarius A* at the Galactic Center
• Collisional Plasma Models with APEC/APED: Emission-Line Diagnostics of Hydrogen-like and Helium-like Ions
• A molecular face-on view of the Galactic Centre region
• Suzaku Observation of G359.79-0.26, a New Supernova Remnant Candidate in the Galactic Center
• X-Ray Imaging Spectrometer (XIS) on Board Suzaku
• Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission

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