Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-09-08
Astronomy and Astrophysics
Astrophysics
11 pages, 19 figures. Accepted for publication in PASJ Suzaku Special Issue (vol. 59 sp. 1)
Scientific paper
We have observed the diffuse X-ray emission from the Galactic center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provide excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. The most pronounced features are FeI K alpha at 6.4 keV and K-shell absorption edge at 7.1 keV, which are from neutral and/or low ionization states of iron, and the K-shell lines at 6.7 keV and 6.9 keV from He-like (FeXXV K alpha) and hydrogenic (FeXXVI Ly alpha) ions of iron. In addition, K alpha lines from neutral or low ionization nickel (NiI K alpha) and He-like nickel (NiXXVII K alpha), and FeI K beta, FeXXV K beta, FeXXVI Ly beta, FeXXV K gamma and FeXXVI Ly gamma are detected for the first time. The line center energies and widths of FeXXV K alpha and FeXXVI Ly alpha favor a collisional excitation (CE) plasma for the origin of the GCDX. The electron temperature determined from the line flux ratio of FeXXV K alpha / FeXXV K beta is similar to the ionization temperature determined from that of FeXXV K alpha /FeXXVI Ly alpha. Thus it would appear that the GCDX plasma is close to ionization equilibrium. The 6.7 keV flux and temperature distribution to the galactic longitude is smooth and monotonic,in contrast to the integrated point source flux distribution. These facts support the hypothesis that the GCDX is truly diffuse emission rather than the integration of the outputs of a large number of unresolved point sources. In addition, our results demonstrate that the chemical composition of Fe in the interstellar gas near the GC is constrained to be about 3.5 times solar.
Brown Gregory V.
Go Tsuru Takeshi
Holt Stephen S.
Hyodo Yoshiaki
Inui Tatsuya
No associations
LandOfFree
Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-111478