High Energy Sky with Advancing Technology

The Galactic Center View From Tenma--Suzaku

Hakucho (1979)96 kg

Tenma (1983) 216kg Ginga（ 1987） 420 kg

ASCA（ 1993） 417 kg

Suzaku (2005) 　 1600 kg

Si S Fe

Tenma: Gas Scintilation Proportional Counter(2 times better resolution)

We found Kα 　 lines from highly ionized Fe, S and Si in the Galactic RidgePresence of High temperature plasma

6.7 keV line

Ginga (large proportional counter) surveyed the Glactic Plane with the 6.7 keV and continuum found excess emision at the Galactic Center

GC

2-10 keV band flux (log scale)

Fe K-line (6.7 keV) flux (linear scale)

Galactic longitude at b=0 deg

The Closed-up View Near the Galactic Center

○ 　 The 6.7 keV line 　　　 region 　 is extended

Center Energy =6.7 keV He-like iron (West) Center Energy < 6.7 keV (East)

2-10 keV

6.7 keV line

Beam size

Center Energy

ASCA (X-ray CCD + Telescope) separated the K-shell lines into the 6.7 (He-like), 7.0 (H-like) and 6.4 keV (neutral) lines

We found 6.4 keV clumps at the molecular clouds, Sgr B and Sgr A.---> puzzle is solved.The spectrum has strong iron line and large absorption near the iron K-edge at 7.1 keV. 　　　　　　　　 　 Fluorescence by external X-raysNo bright X-ray source is found

The illuminating source was bright in the past, but faint at present

The Center of the Galaxy in the Recent Past: A view from GRANAT

Sunyaev et al. 1993,

ASCA View of Our Galactic Center: Remains of Past Activities in X-Rays? Koyama et al., 1996, PASJ, 48.

Rasid Sunyaev and I met with each other with the same idea.

Suzaku found K α 　 lines of highly ionized Ar, Ca, Cr, Mn , Fe and Ni (red) and those of neutral (blue ) 　

:Z=　1.6　solar　　　　　　4　solar

The EWs ( absolute values and distribution pattern) are consistent with the X-ray fluorescent origin from clouds of 1.6 solar abundances. Electron origin requires more than 4 solar for all elements ! 　

l-distribution of the 6.4 keV lines

Sgr A

Discoveries of New 6.4 keV Clouds

Sgr B2Sgr B1M0.74-0.09

M359.43-0.07M359.47-0.15M359.43-0.12M359.38-0.00 M359.23-0.04

M0.1-0.1Arches G0.174-0.223G0.162-0.127

1994 年 2004 年

2005 年2000 年

Rapid Time-Varaibility of Sgr B2

6.4 keV line :Koyama et al. 2008, Inui et al. 2009, Hard X-rays :Terrier et al. 2010

ASCA XMM-Newton

Chandra Suzaku

Suzaku found simultaneous variablity of the 6.4 keV line & Hard X-rays in Sgr B2

2005 2009

The rapid/simultaneous variability strongly supports the X-ray fluorescence origin irradiated by an external big but short X-ray flare.

What is the external flare ?

Parabolax2+y2=(300-y)2

(Unit is light-year)Sgr A* Flare ~300 years agoFermi bubble 　 ?Quasar-like activity 1Myears ago （ Su, M. et al. 2010)

Face-on View 　 of the 6.4 keV cloud(e.g. Ryu et al. 2009)

Near side GCDX is not absorbed by the cloud, while far side is heavily absorbed by the cloud.=> Face on position of the cloud

The END