1 / 12

1) Origin of 6.7/6.9 keV (He-like/H-like Fe Ka) Lines

Spectroscopic Study of the Galactic Center X-Rays with Suzaku Katsuji Koyama, Kyoto University. 1) Origin of 6.7/6.9 keV (He-like/H-like Fe Ka) Lines : Collisional Excitation or Charge Exchange 2) Discoveries of New SNR Candidates 3) Origin of 6.4 keV (Neutral Fe Ka) Line

hakeem-knox
Download Presentation

1) Origin of 6.7/6.9 keV (He-like/H-like Fe Ka) Lines

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Spectroscopic Study of the Galactic Center X-Rays with Suzaku Katsuji Koyama, Kyoto University • 1) Origin of 6.7/6.9 keV (He-like/H-like Fe Ka) Lines • : Collisional Excitation or Charge Exchange • 2) Discoveries of New SNR Candidates • 3) Origin of 6.4 keV (Neutral Fe Ka) Line • : X-Ray Reflection or Electron Bremsstrahlung • : Time Variability of the 6.4 keV clumps • How reliable our “Energy scale calibration” is. • (For detail, please read PASJ special issue)

  2. H-like Observed (eV) Lab D(eV) ----------------------------- S Lya2622 (+4-3) 2622 0 Fe Lya 6970 (+3-2) 6966 4 Mn Ka 5900 (+2-1) 5895 5 Energy Scale Check Using the H-like Lya                 andNeutral Ka    Origin of the 6.7 keV (He-like Fe Ka) Line Charge Exchange or Collisional Excitation ? Collisional Excitation  6680-6685 eV Charge Exchange  6666eV f r i r He-like Ka complex i f l l He-like Fe Ka= 6680 (+-1) eV: Close to 6680-6685eV in Collisional Excitation

  3. 6.9 keV (H-like Lya) is very narrow < 20 eV = Fe velocity < 1000 km/s Lyman Series n>8  n=1 Collisional Excitation (High Temperature Plasma) is more likely Originfor 6.9 keV

  4. Parametersof the GC plasma Ionization Temperature (kTi) Fe KaH-like/He-like: kTi=6.5 keV +/- 0.1 keV Fe Kb H-like/He-like: kTi=5.1 keV + 1.5 -1.0 keV Ni Ka H-like/He-like : kTi=9.3 keV +1.6 -2.5 keV Electron Temperature (kTe) He-like Fe Kb/Ka : kTe=6.2 keV +3 -1 keV H-like Fe Kb/Ka : kTe > 6.5 keV (lower limit) Centroid of He-like Kamoves with Ionization temperature due to the satellite lines. The Center Energy of Ka (He-like) : kTi= 2.5-6.5 keV All the results are consitent with the plasma of kTi = kTe (CIE) = 6.5 keV.

  5. 2. Discovery of New SNR Candidates 6.7 keV map Sgr A East 2.45 keV map

  6. 6.4 keV Map 3. Discovery of 6.4 keV clumps Origin of the 6.4 keV clumps Is this Inner shell IonizationbyElectrons or X-rays ?

  7. Inner Shell Ionization Electrons vs X-rays --------------------------------------------- Equivalent witdh (keV) of the 6.4 keV line 0.3 - 0.6 1 - 1.5 Energy (keV) of the Max Cross Section 10-100 7.1 Absorption NH (cm-2) ~1021~1024 Electron X-ray 1021 1024

  8. Most of the 6.4 keV clumps show strong Ka line with the equivalent width of 1.1 – 2.1 keV ,and deep K-edge absorption with 2 – 10 x 1023 cm-2 >> 1 x 1023cm-2 ( the interstellar absorption to the GC) Thus ionization by X-rays is more likely. Further more We found a large time variability.

  9. G0.570 Sgr B2 ~10pc 6.4 keV line History of Sgr B2 from 1994 to 2005

  10. 6.4 keV 6.4 keV 6.7 keV 6.7keV 6.4keV: Full region 6.4keV: Sgr B2 cloud 6.7keV: Full region 6.4keV: G 0.570-0.018

  11. Physical size of the clump complex is nearly 10 pc. Therefore, such a large flux change within 10 years is impossible by any charged particle. Only possible scenario of this time variability is due to an irradiation of variable X-rays (X-ray Reflection Nebula). More than a few hundred years ago, Sgr A* had been very active in X-rays; it was 106 times brighter than present at ~300 years ago, and decayed to less than a half after ~10 years. The X-rays hit the Sgr B clouds after ~300-years travel. The clouds re-emitted the 6.4 keV photons. Like a time delayed-echo, the X-ray echo is now just arriving at the Earth, when Sgr A* is falling into a quiescent state.

  12. Conclusion of the Galactic CenterDiffuse X-rays (1) Origin of the 6.7/6.9 keV Lines High Temperature Plasma in CIE (2) We have discovered New SNR Candidates (3) Origin of the 6.4 keV Line X-Ray Reflection The 6.4 keV clumps near Sgr B2 are time variable as a reflection of a past outburst of Sg A*

More Related