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XMM-Newton Observation of the Centaurus cluster. Isao Takahashi, Madoka Kawaharada, Kazuo Makishima, Yasushi Ikebe A , and Takayuki Tamura B (University of Tokyo, A JCA/UMBC, B ISAS). Introduction. The Centaurus cluster. Near ( z = 0.0104) and luminous ( F ~ 10 -10 erg/sec/cm 2 )
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XMM-Newton Observation of the Centaurus cluster Isao Takahashi, Madoka Kawaharada, Kazuo Makishima, Yasushi IkebeA, and Takayuki TamuraB (University of Tokyo, AJCA/UMBC, BISAS)
Introduction The Centaurus cluster • Near (z = 0.0104) and luminous (F ~ 10-10 erg/sec/cm2) • Outstanding central cool emission around the cD galaxy Our results on Centaurus with ASCA • Fukazawa et al. PASJ 46 L55 (1994) Hot component exists even in the center Strong metal concentration toward the center hot (~ 4 keV) + cool (~ 1.5 keV) • Ikebe et al. ApJ 525 58 (1999) Two-phase plasma Double-beta potential Confirmthe ASCA picture by XMM-Newton Search new facts beyond ASCA
Chandra 0.5 – 7 keV Image 7 10’ = 125 h75-1 kpc 1’ softness ratio map 1 1 ASCAGIS XMM MOS 6 5 4 arbitrary 1 2 3 10-3 0.1 Prominent soft excess at r < 1’ “Plume-like” structure (Sanders & Fabian 2002) ~ XMM Observation ; Jan. 2002 (PI = Y. Ikebe) Exposure ~ 35 ksec 0.5 – 1.5 keV (0.5-1.5) / (2-5) keV
Spectra at various radii 1 1 10-2 10-2 Photons (arbitrary unit) Photons (arbitrary unit) 10-4 10-4 10-6 10-6 1 1 2 2 5 5 10 10 0.5 0.5 Energy (keV) Energy (keV) XMM MOS ASCA GIS 1 0-1’ 2 123 3 4 4 5 5 6 6 7 7 0-10” 10-30” 30-60” 1-2’ 2-3.5’ 5-6.5’ 8.5-11’ 1-2’ 2-3.5’ 5-6.5’ 8.5-11’ 18.5-40’ At least three typical temperatures (~ 4 keV, ~2 keV, < 1 keV) are seen
Results of 1T and 2T fit Filling factor of the cool phase 3.8 + 1.7 keV (both fixed) 0.5 ASCA (Ikebe et al.) 4 0.1 0.05 Temperature (keV) Fe abundance 2 1 0.5 0 0.1 0.5 1 5 10 Radius (arcmin) 0.1 1 5 10 Radius (arcmin) • Single temperature model • Two-phase model Statistically comparable ~ 0.7 keV component from very center Generally consistent with ASCA
Integrate r < 1’ RGS spectrum 2×10-3 1′ FeXVII ′ FeXVIII ″ flux (cts/sec/cm2/angstrom) x2/d.o.f = 1206/895 FeXIX FeXX FeXXI FeXXII FeXXIII FeXXIV 0 20 (1.24 keV) (0.83 keV) Mg, Ne, O wavelength in rest frame (angstrom) 15 10 At least two components are required Generally consistent with EPIC results
Differential emission measure analysis 104 103 Isobaric Cooling Flow ⊿(emissionmeasure) / ⊿ log T 102 10 ASCA 1 0.2 0.3 0.5 1 2 3 5 Plasma temperature (keV) multi components fit (Ti / Ti+1 = 1.5) cf. Tamura et al. 2003 determine TMAX and each normalization Discrete kT distribution seems to be favorable Not so much lowest kT components
Summary kT (keV) L (h75-2 erg/s) ratio 1.7 5 x 1042 10 0.7 5 x 1041 1 4 5 x 1043 100 • XMM results are consistent with previous ASCA results (Fukazawa et al., Ikebe et al.) • There are 3 typical plasma temperatures • 0.7 keV plasma component, which was not detected by ASCA, exists at the very center • Cool emission with kT < 0.5 keV is insignificant