X-RAY DIAGNOSTICS OF GIANT MOLECULAR CLOUDS IN THE GALACTIC CENTER REGION AND PAST ACTIVITY OF Sgr A*

Journal Article · Thu Oct 20 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/740/2/103; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21587332

Odaka, Hirokazu; Watanabe, Shin; Tanaka, Yasuyuki; Khangulyan, Dmitry; Takahashi, Tadayuki ^[1]; Aharonian, Felix ^[2]

---

1. Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Sagamihara, Kanagawa 252-5210 (Japan)
2. Dublin Institute for Advanced Studies (DIAS), 31 Fitzwilliam Place, Dublin 2 (Ireland)

Strong iron fluorescence at 6.4 keV and hard-X-ray emissions from giant molecular clouds in the Galactic center region have been interpreted as reflections of a past outburst of the Sgr A* supermassive black hole. Careful treatment of multiple interactions of photons in a complicated geometry is essential to modeling the reprocessed emissions from the dense clouds. We develop a new calculation framework of X-ray reflection from molecular clouds based on Monte Carlo simulations for accurate interpretation of high-quality observational data. By utilizing this simulation framework, we present the first calculations of morphologies and spectra of the reflected X-ray emission for several realistic models of Sgr B2, which is the most massive molecular cloud in our Galaxy. The morphology of scattered hard X-rays above 20 keV is significantly different from that of iron fluorescence due to their large penetrating power into dense regions of the cloud, probing the structure of the cloud. High-resolution spectra provide quantitative evaluation of the iron line including its Compton shoulder to constrain the mass and the chemical composition of the cloud as well as the luminosity of the illuminating source. These predictions can be checked in the near future with future X-ray missions such as NuStar (hard X-rays) and ASTRO-H (both iron lines and hard X-rays).

• OSTI ID: 21587332
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 740; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
CALCULATION METHODS
CHEMICAL COMPOSITION
CLOUDS
COMPUTERIZED SIMULATION
ELECTROMAGNETIC RADIATION
ELEMENTS
EMISSION
FLUORESCENCE
GALAXIES
HARD X RADIATION
IONIZING RADIATIONS
IRON
LUMINESCENCE
LUMINOSITY
METALS
MONTE CARLO METHOD
MORPHOLOGY
OPTICAL PROPERTIES
PHOTON EMISSION
PHYSICAL PROPERTIES
RADIATIONS
SCATTERING
SIMULATION
SPECTRA
TRANSITION ELEMENTS
X RADIATION
X-RAY SPECTRA