K. MakishimaCooling Flow, 31 May 2003 The ASCA View on Cooling Flows and its Implications K. Max Makishima (U. Tokyo /RIKEN) in collaboration with Yasusi Ikebe, Yasusi Fukazawa, Kyoko Matsushita, Haiguan Xu, Takayuki Tamura, Isao Takahashi, and Madoka Kawaharada Makishima et al. PASJ, 53, 401 (2001) 1. ASCA and the Gas Imaging Spectrometer 2. Summary of the ASCA Results 3. Physics in the “post-CF” Era 4. The Prospect for ASTRO-E2

K. MakishimaCooling Flow, 31 May ASCA and the GIS Ohashi et al. PASJ 48, 157 (1996) Makishima et al. PASJ 48, 171 (1996) Energy (keV) 0.1 1e-2 1e-3 1e-4 cts/sec/cm 2 /keV Blanck sky (CXB+NXB) Sunlit earth (solar X-ray+ NXB) Mg Si S Ar Night earth (NXB) Cu GIS background spectra 45 arcmin Fornax Cluster with the GIS

K. MakishimaCooling Flow, 31 May EM cool /EM hot Hot component temperature (keV) A2199 A1795 A2147 A119 A496 3A0335 A3558 A1060 Hydra-A A2634 A2063 A4059 A400 MKW3s Virgo Cen AWM7 A539 AWM4 A262 2a. The central cool emission is exclusively associated with cD galaxies cD clusters (B-M I, I-II, or II) non-cD clusters (B-M II or III) 2. Summary of the ASCA Results Consistent with previous knowledge From 2T fits

K. MakishimaCooling Flow, 31 May b: The cool ICM phase is metal-enriched -According to the CF scenario, a metal-rich portion would cool and disappear quickly -- a contradiction. -The chemical abundance of ICM differs between the central and outer regions (Fukazawa et al. MNRAS 313, 21, 2000) -The cool component appear to be associated with the cD galaxy, rather than with cooling portion of the ICM.

K. MakishimaCooling Flow, 31 May 2003 CF rate with ASCA (M 0 /yr) A1795 Hydra-A A2199 A496 3A0335 MKW3s Centaurus Virgo AWM7 A262 CF rate before ASCA (M 0 /yr) - Hot emission from the cluster core was mistaken for the cool emission. - The central potential “dimple” was not properly considered Ikebe et al. (1997) - Xu et al. (1998) - Ikebe et al. (1999) - Makishima et al (2001) Reconfirmed with Chandra and XMM-Newton 2c. The CF rate was previously overestimated A good example will be given by the next speaker

K. MakishimaCooling Flow, 31 May 2003 Projected radius (arcmin) 101 ASCA GIS keV 101 ASCA GIS 3-10 keV Beta model (convolved) 100 kpc The central excess surface brightness is nearly color- independent (A1795; Xu et al. ApJ 500,738, 1998). 2d. The centrally peaked surface brightness is due to central potential deepening Surface brightness (a.u.) 1-beta fits (95 clusters) 2-beta fits (26 clusters) Core radius (Mpc) Number 60 kpc 220 kpc The ICM profile involve two spatial scales (ROSAT+ASCA; Ota et al. ApJL 567, L23, 2002).

K. MakishimaCooling Flow, 31 May e. The central cool component traces the central potential deepening Ikebe astroph/ ASCA A1795 EPIC-MOS EPIC-PN Temperature (keV) Projected radius (arcmin) T cool ~ T hot / 2, with a common radial temperature profile (Ikebe astro-ph/ ; Allen et al. MNRAS 328, L37, 2001) Temperature (keV) Log L X (erg/s) Cool component obeys the same L x -T relation as the entire cluster sample Most detailed 2T analysis: Ikebe et al. ApJ 525, 58 (1999) T cool may simply reflect the central potential depth

An isothermal hot ICM fills the entire potential well. A two-phase region is produced within the central potential dimple, by an admixture of metal-rich cool plasma. A hierarchical potential is formed by the cluster and the cD galaxy. 2f. The ASCA view of a cD cluster -- “Double-beta” and “2T” (Ikebe et al. ApJ, 525, 58,1999)

K. MakishimaCooling Flow, 31 May b. Simple-minded considerations 3a. Conclusion from Makishima et al. (2001) Through the ASCA study, we have arrived at a novel view on central regions of galaxy clusters. It describes the region around a cD galaxy as a site of significant and active evolution, where plenty of heavy elements are produced, a self-gravitating core develops, the stellar component condensates to the center, and the liberated energy is deposited onto the X-ray emitting plasmas. The scenario makes a sharp contrast to the previous view which emphasized the role of radiative plasma cooling. Novel X-ray information to be available with Chandra, XMM-Newton, and hopefully the rebuilt ASTRO-E will be utilized for further examination of our scenario. Through the ASCA study, we have arrived at a novel view on central regions of galaxy clusters. It describes the region around a cD galaxy as a site of significant and active evolution, where plenty of heavy elements are produced, a self-gravitating core develops, the stellar component condensates to the center, and the liberated energy is deposited onto the X-ray emitting plasmas. The scenario makes a sharp contrast to the previous view which emphasized the role of radiative plasma cooling. Novel X-ray information to be available with Chandra, XMM-Newton, and hopefully the rebuilt ASTRO-E will be utilized for further examination of our scenario. 3. Physics in the “Post-CF” Era

K. MakishimaCooling Flow, 31 May b. A simple idea (Makishima 1994) - ICM, DM, and galaxies have ~ the same specific energy. - Since alaxies have much lower specific entropy than ICM, the free energy will be transferred from galaxies to ICM. - Galaxies will lose energy and fall to the cluster center. High z Low z Evolution?

K. MakishimaCooling Flow, 31 May c. Supporting evidence - In angular extent, stars < DM < ICM -- Energy of the galaxies was transferred to the ICM. - Evidence for gradual galaxy mergers in the cluster center -- Dynamical energy of galaxies was extracted, and was deposited on the ICM. --> Poster #17. “The Dark Group Candidate, RXJ ” by Kawaharada et al. - The central decrease in Iron- Mass-to-Light -Ratio (IMLR) -- Galaxies gradually fell to the center while ejecting metals IMLR Centaurus e-3 1e-4 A1060 3D radius (kpc) Radial IMLR profiles - The O-profile is flatter than the Fe-profile -- Early SNe II occurred over an extended region, while subsequent SNe Ia occurred closer to the center.

K. MakishimaCooling Flow, 31 May d. Numerical estimates - The expected galaxy-to-ICM energy transfer rate ; -dE/dt ~ N  R i 2 n m p v 3 (Sazazin 1988, p.152) ~ 2x10 44 (N /300) (R i /10kpc) 2 (n/10 -3 ) (v/500 kms -1 ) 3 erg/s (N=galaxy number; R i = interaction radius; n=ICM density; v=galaxy velocity dispersion) - The intra-cluster magnetic fields are easily “pushed away” by moving galaxies that are good electrical conductors. This makes R i ~ DM halo of each galaxy. - The available total dynamical energy in galaxies; E ~ 5x10 62 (M gal /10 14 M 0 ) (v/500 kms -1 ) 2 ergs E/(dE/dt) ~ 80 Gyr

K. MakishimaCooling Flow, 31 May 2003 Reconnection sites Hot phase Cool phase Magnetic field lines Galaxy motion/rotation - Ordered magnetic fields separate the hot and cool phases. - Galaxies’ kinetic energy -- > MHD turbulence -- > reconnection -- > plasma heating & particle acceleration - The loop-like structure stabilizes the heating/cooling. 3c. A speculative view -- the “cD corona”

4. The Prospect for ASTRO-E2 The first improved version of the M-5 rocket has been launched successfully on 2003 May 9, putting “Sample-Return” mission into an interplanetary orbit. We are re-building the Hard X-ray Detector (HXD). The recovery mission ASTRO-E2 will be launched in The XRS (D       measures the expected ICM turbulence. -The HXD ( keV) searches for particle acceleration. -The XIS (CCD camera) studies the ICM heating process.

K. MakishimaCooling Flow, 31 May 2003 Conclusion - - Using ASCA, we have pointed out for the first time that the CF hypothesis needs a significant revision. - - The view has been reinforced by XMM- Newton and Chandra. - - We propose that the dynamical energy in the galaxy motion is dissipated onto the ICM. - - ASTRO-E2 will open the new era of such post-CF physics.

K. MakishimaCooling Flow, 31 May 2003