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

K. Makishima Cooling 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 Spectrometer2. Summary of the ASCA Results3. Physics in the “post-CF” Era4. The Prospect for ASTRO-E2


1. ASCA and the GIS Ohashi et al. PASJ 48, 157 (1996)Makishima et al. PASJ 48, 171 (1996)

0.5 1 2 5 10Energy (keV)

0.1

1e-2

1e-3

1e-4

cts/

sec/

cm2 /

keV

Blanck sky (CXB+NXB)

Sunlit earth (solar X-ray+ NXB) Mg

SiS

Ar

Night earth (NXB)

Cu

GIS background spectra

45 arcmin

Fornax Cluster with the GIS


0.01

0.1

1

2 3 4 5 6

EM

coo

l /E

M h

ot

Hot component temperature (keV)

A2199

A1795

A21

47

A11

9

A4963A0335

A35

58

A10

60

Hydra-A

A2634

A2063

A40

59

A40

0

MK

W3s

VirgoCen

AWM7

A53

9

AW

M4

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


EMcool / EMhot0

0.2

0.4

0.6

0.8

1

0.01 0.1 1

Cen

tral

iron

abu

ndan

ce (

sola

r)

Centaurus

VirgoAWM7A262

A496A2199

A2063

A539A1060A400

cD clustersNon-cD clusters

2b: 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.


CF

rat

e w

ith

ASC

A (

M0 /

yr)

A1795

Hydra-A

A2199A496

3A0335

MKW3s

Centaurus

VirgoAWM7

A262

CF rate before ASCA (M0 /yr)

- Hot emission from the cluster core was mistaken for the cool emission.

- The central potential “dimple” was not properly considered.

100101

10

100- 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


Projected radius (arcmin)101

ASCA GIS 0.7-3 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. Ap

J 500,738, 1998).

2d. The centrally peaked surface brightness is due to central potential deepening

Sur

face

bri

ghtn

ess

(a.u

.)

1-beta fits(95 clusters)

2-beta fits(26 clusters)

15

10

5

0

8

6

4

2

00.03 0.1 0.3 1 Core radius (Mpc)

Num

ber

60 kpc

220 kpc

The ICM profile involve two spatial scales (ROSAT+ASCA; Ota et al. A

pJL 567, L23, 2002) .


2e. The central cool component traces the central potential deepening

Ikebe astroph/0112132

ASCA

A1795

EPIC-MOSEPIC-PN

8

6

4

2Tem

pera

ture

(ke

V)

0.1 0.2 0.5 1 2 5 10Projected radius (arcmin)

Tcool ~ Thot / 2, with a common radial temperature profile (Ikebe astro-ph/0112132 ; Allen et al. MNRAS 328, L37, 2001)

44

43

42

41

40 1 2 5 10

Temperature (keV)

Log

LX (

e rg /

s )Cool component

obeys the same Lx-T relation as the entire

cluster sample

Most detailed 2T analysis: Ikebe et al. ApJ 525, 58 (1999) Tcool 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)


3b. 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


3b. 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?


3c. Supporting evidence- In angular extent, stars < DM < I

CM -- 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 0419+2225” by Kawaharada et al.

- The central decrease in Iron-Mass-to-Light -Ratio (IMLR) -- Galaxies gradually fell to the center while ejecting metals.

20 50 100 200 300

IML

R

Centaurus

0.01

1e-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.


3d. Numerical estimates- The expected galaxy-to-ICM energy transfer rate ;

-dE/dt ~ N Ri2 n mpv3 (Sazazin 1988, p.152)

~ 2x1044 (N /300) (Ri /10kpc) 2 (n/10-3) (v/500 kms-1)3 erg/s

(N=galaxy number; Ri= 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 Ri ~ DM halo of each galaxy.

- The available total dynamical energy in galaxies;

E ~ 5x1062 (Mgal /1014 M0) (v/500 kms-1)2 ergs

E/(dE/dt) ~ 80 Gyr


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-E2The 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 2005.

- The XRS (D measures the expected ICM turbulence.

- The HXD (10-600 keV) searches for particle acceleration.

- The XIS (CCD camera) studies the ICM heating process.


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.


Documents

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