Aug , 2006 KJYAM 慶州 1 Suzaku Observation of Nearby Seyfert 2 Galaxy NGC 4945 Naoki Isobe (RIKEN, Japan) and Suzaku NGC 4945 team

Aug , KJYAM 慶州 Introduction of Suzaku “ 朱雀 ” The 5 th Japanese X-ray observatory. Launched in July 10, 2005 Investigation of structure formation of universe Black holes (inclusding AGNs) etc. Scientific observations SWG phase from 2005/08 AO-1 from 2006/04 Call for AO-2, this December uzaku/index.html.en Suzaku Launch of Suzaku (from Uchinoura Space Station)

Aug , KJYAM 慶州 Instrument on Suzaku XRT (X-Ray Telescope) large effective area (450cm keV) XIS (X-ray Imaging Spectrometer) 4CCD cameras (0.2 – 12 keV) 1 Back-illuminated (XIS1) 3 Front-illuminated (XIS0,2,3) Low background, Good energy resolution and high sensitivity HXD (Hard X-ray Detector) Si-PIN diode (10-60 keV) and GSO scintillator ( keV) Wide energy band and low background Suzaku XRT XIS HXD

Aug , KJYAM 慶州 Seyfert 2 Galaxies with Suzaku Molecular Torus Hot gas Super massive black hole Accretion disk Seyfert 1 Seyfert 2 Direct but absorbed component Scattered component Reflected component E [keV] Flux Suzaku is best Chandra/Newton

Aug , KJYAM 慶州 NGC 4945 Nearby edge-on spiral galaxy (Ott et al. 1995) at 3.7 Mpc (Mauersberger et al. 1996) M BH = 1.4x10 6 M sun (Greenhill et al. 1997) Starburst activity (Moorwood et al. 1996) The nucleus is heavily absorbed (N H ～ 4x10 24 cm -3 ; Compton-thick) The brightest Seyfert 2 above 20 keV (Done et al. 1996; Madejski et al. 2000). Suzaku observations 2005 Aug. 22 (25 ksec) 2006 Jan. 15 (100 ksec) Chandra Image 5”5” Chandra + RXTE

Aug , KJYAM 慶州 Suzaku XIS image of NGC 4945 The X-ray peak coincides with the center of the host galaxy X-ray emission is elongated along the host galaxy. Some point sources are detected. A new transient source (ULX) is found at the south- west arm in the 2 nd exposure. (Isobe et al. in prep.) XIS FI image in 0.5 – 10 keV, with IR (Jarette et al. 2003) contours overlaid 2005/8/ X-ray sources detected with XMM-Newton 2006/1/15-17

Aug , KJYAM 慶州 Suzaku X-ray Lightcurve The XIS lightcurves show almost no significant variability both in 0.5 – 2 keV and 2 – 10 keV (< 20 %). The Fe K  band (6.2 – 6.6 keV) lightcurve shows significant variation, with a time scale of 10 ksec. The HXD PIN lightcurve shows a factor of 3 variability, with a time scale of ～ 10 ksec. The HXD PIN hardness ratio stays relatively constant, indicating almost no spectral change. Time [ksec]

Aug , KJYAM 慶州 Suzaku HXD Spectra X-ray signals are detected above 100 keV with HXD. Spectral fitting PL model N H = (4.6±0.5) x cm -2  = 1.83 ± 0.08 Cutoff PL model E cut > 100 keV  = 1.4 ± 0.4 The HXD data is dominated by the absorbed nucleus, has no significant contribution from the reflection component. PIN GSO Energy [keV] Flux

Aug , KJYAM 慶州 Suzaku XIS spectra The XIS spectra The XIS spectra below 2 keV show a thermal nature. below 2 keV show a thermal nature. avobe 2 keV show a hard spectrum avobe 2 keV show a hard spectrum show significant Fe lines show significant Fe lines Fe lines are clearly resolved keV : Fe Ka 7.05 keV : Fe Kb 6.68 keV : Fe XXV (He-like) Fe lines Thermal XIS FI / BI Hard spectrum Reflection

Aug , KJYAM 慶州 Wide-band X-ray Spectrum Absorbed nucleus  = 1.64 N H = 4.1 x cm -2 L keV ～ ergs s -1 Reflection component Continuum : about 1 % of absorbed nucleus Fe lines : EW K  = 1.2 keV EW Kb = 0.2 keV Hot thermal emission kT = 5.5 keV Soft thermal emission from the host galaxy kT = 0.3 keV XIS PINGSO Spectral Energy Distribution of NGC 4945

Aug , KJYAM 慶州 Comparison with previous observations The nucleus of NGC 4945 shows only a factor of 2 variation in its activity. The spectral parameters stay relatively constant. Ginga : Iwasawa et al BeppoSAX : Guainazzi et al RXTE : Madejski et al RXTE/Chandra : Done et al. 2003

Aug , KJYAM 慶州 Summary Suzaku observed the nearby Seyfert 2 galaxy NGC 4945 on 2005/08/22 and 2006/01/15. Suzaku observed the nearby Seyfert 2 galaxy NGC 4945 on 2005/08/22 and 2006/01/15. The X-ray signals are significantly detected in the 0.5 – 200 keV range. The X-ray signals are significantly detected in the 0.5 – 200 keV range. The wide band X-ray spectrum of NGC 4945 is decomposed into the absorbed nucleus, reflection and scattered component including significant Fe lines, and thermal emission from the host galaxies. The wide band X-ray spectrum of NGC 4945 is decomposed into the absorbed nucleus, reflection and scattered component including significant Fe lines, and thermal emission from the host galaxies. The absorbed nucleus shows a factor of 3 intensity variation, without any spectral change. The absorbed nucleus shows a factor of 3 intensity variation, without any spectral change. However, in order to finalize our result, the HXD background improved accuracy will be required. However, in order to finalize our result, the HXD background improved accuracy will be required. A new transient source was discovered in the second exposure. A new transient source was discovered in the second exposure.

Aug , KJYAM 慶州 Suzaku NGC 4945 team R. E. Griffith (leader), G. C. Dewangan (CMU) R. E. Griffith (leader), G. C. Dewangan (CMU) N. Isobe (Co-leader, RIKEN) N. Isobe (Co-leader, RIKEN) K. Makishima, T. Itoh (Tokyo U) K. Makishima, T. Itoh (Tokyo U) N. Anabuki (Osaka U) N. Anabuki (Osaka U) H. Awaki (Ehime U) H. Awaki (Ehime U) G. M. Madejski (SLAC) G. M. Madejski (SLAC) T. Okajima, J. N Reeves (NASA/GSFC) T. Okajima, J. N Reeves (NASA/GSFC) T Takahashi (JAXA/ISAS) T Takahashi (JAXA/ISAS) Y. Ueda (Kyoto U) Y. Ueda (Kyoto U) T. Yaqoob (JHU) T. Yaqoob (JHU)

Aug , KJYAM 慶州 Introduction of myself Name : Naoki Isobe Name : Naoki Isobe Date of Birth : April 10, 1974 (32 years old) Date of Birth : April 10, 1974 (32 years old) Nationality : Japanese Nationality : Japanese Institute : Cosmic Radiation Laboratory, RIKEN Institute : Cosmic Radiation Laboratory, RIKEN Position : Post. Doc. Position : Post. Doc. Research field : X-ray Astronomy, AGN Research field : X-ray Astronomy, AGN