1. X-ray follow-ups of TeV unID sources using Suzaku Aya, T. Bamba (ISAS/JAXA, Japan) R. Yamazaki, K. Kohri, H. Matsumoto, H. Yamaguchi, G. Pühlhofer, S. J. Wagner

2. 1.1. Origin of Cosmic rays TeV electron IS B. (~  G) synchrotron X-rays Who and how to accelerate cosmic rays up to knee ? diffusive shock acc. in shocks ? = biggest problem ! How to search for accelerators ? hard X-rays and TeV gamma-rays are the best for the accelerator search. difficulties: r g ~ pc in interstellar B -> we cannot point out accelerators Inverse Compt. (e) pion decay (p) TeV gamma-rays

3. (Aharonian+ 2006) 1.2. New Candidates: TeV unID sources A lot of sources are discovered from the GP They are not known PSRs, PWNe known SNRs known SF regions known EGRET source “TeV unID sources” “dark particle accelerators” X-ray follow-ups are needed !

4. 1.3. X-ray follow-ups of TeV unIDs (1): known categories HESS J1813-178 XMM-Newton (Funk+ 2007) PWN !! SNR !! CTB37B Suzaku (Nakamura+ submitted) Many samples are PWN HESS J1837-069 Chandra (Gotthelf+ 2008) HESS J1718-3825 XMM-Newton (Hinton+ 2007) (See also Pühlhofer’s invited talk, Uchiyama+ poster D12)

5. 1.4. X-ray follow-ups of TeV unIDs (2): unknown categories No counterpart !! HESS J1616-508 Suzaku (Matsumoto+ 2007) Molecular cloud ?? Galactic center region radio obs. (Aharonian+ 2006) Some source but unID !! HESS J1614-518 Suzaku (Matsumoto+ 2008) Compact unID sources !! HESS J1804-218: Suzaku (Bamba+ 2007) Many kinds of TeV unIDs !

6. 2.1. One of the most mysterious TeV unIDs : HESS J1745-303  Discovered by H.E.S.S. (Aharonian+ 2005)  Near the Galactic Center  One of the most extended source (~0.5 deg)  Rather soft (Gamma=2.7) and bright (5.2x10 -12 ergs cm -2 s -1 )  No couterpart ! This one ! -> Suzaku is the best tool for the counter part search: low and stable bgd 50ks x 4 pointing mapping obs. color: TeV contour: molecular cloud 0.5 deg

7. 0.5-2.0 keV (Suzaku) contour: HESS 2.2. Suzaku image of HESS J1745-303 (1) SNRs G359.0-0.9, G359.1-0.5 (Bamba+ 2000) ROSAT sources No X-ray !

8. 2.0-8.0 keV (Suzaku) contour: HESS 2.3. Suzaku image of HESS J1745-303 (2) No X-ray !

9. 2.4. Suzaku image of HESS J1745-303 (3) Some excess on HESS J1745-303 ?? 6.4 keV ion line (Suzaku) contour: HESS

10. src bgd1 bgd2 3.1. Spectral Analysis (1) continuum comp. Src: TeV peak region bgd: TeV free region Compare the flux (Assuming Gamma = 2.0) F 2-10 keV < 2.1 x 10 -13 ergs cm -2 s -1 c.f. F 1-10 TeV = 5.2 x 10 -12 ergs cm -2 s -1 F 1-10TeV F 2-10keV > 25 one of the most X-ray faint TeV unIDs!

11. 6.4 keV flux density6.7 keV flux density6.4/6.7 (ph/cm 2 /s/arcmin 2 ) src:6.5e-8 ± 0.7e-81.1e-7 ± 0.08e-70.58 ± 0.03 bgd1:5.9e-8 ± 2.2e-81.2e-7 ± 0.2e-70.49 ± 0.20 Src region has stronger 6.4 keV line although the statistics is not enough … Src bgd1 5.9keV (MnKa: bgd) 6.4keV (neutral Fe) 6.7keV (He-like Fe) Ni Ka (bfd) 3.2. Spectral Analysis (2) neutral iron line total excess: 6.1x10 -6 ph cm -2 s -1 src bgd1 bgd2

12. (Bitran+ 1997) (Aharonian+ 2008) 4.1. Discussion 1: Nonthermal continuum emission F 2-10 keV < 2.1 x 10 -13 ergs cm -2 s -1 F 1-10 TeV = 5.2 x 10 -12 ergs cm -2 s -1 F 1-10TeV F 2-10keV > 25 different from known sources (SNR/PWN …) c.f. Crab: F TeV /F X ~3x10 -3 RXJ1713: F TeV /F X ~ 0.06 The TeV gamma-ray emission from the GC MCs MC are faint in nonthermal X-rays HESS J1745 coinsides with MC (Aharonian+ 2008) HESS J1745 could emit TeV gamma-rays in the same way of the TeV GC emission

13. 4.2. Discussion 2: neutral iron line neutral iron line near the GC, coinside with MC = reflection on the MC by the past bright GC (Koyama+ invited talk, Murakami+ 2001) Sgr B2 HESSJ1745 line Int.5.6e-5 6.1e-6 M MC 6e6 M o 5e4 M o size0.05 deg. 0.3 deg. d from GC0.7 deg. 1.2 deg. line int. ~ mass x viewing angle ~ mass x (size) 2 x (distance) -2 The neutral iron line can be explained by X-ray reflection of the past bright GC HESS J1745-303 – MC association in the GC region ! could be similar source to the TeV GC emission HESSJ1745: 7.0e-6 ph cm -2 s -1 Where is the CR source ?? G359.1-0.5 ?? Cosmic rays make TeV emission with attacking MC ??? (Aharonian+ 2006)

14. 5. Summary  The origin of TeV unID sources are still unknown.  HESS J1745-303 is one of the most interesting source near the Galactic center.  We made deep X-ray follow-ups of HESS J1745-303 with Suzaku.  We made tight upper-limit in the X-ray band.  The excess of neutral iron line is found from the MC, which could associate the TeV unID.  HESS J1745-303 could be TeV emission from a MC with CR attacking like GC diffuse TeV emission.  In order to pinpoint the origin of this interesting source, more follow-ups are needed in other wavelengths.