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Chapter 6
Analysis and Results
6．1 A1413
We observed the northern region of A1413 with the Suzaku XIS de七ectors． In table 4．3，
we give the details of our observation， and in figure 8．4（a）， we show the XIS field of view
（FOV）superimposed on the X1班匹1Ve耐oηimage of A1413． The XIS ins七rument consists
of 4 CCD chips；one back−illuminated（BII XIS1）and three ffont−illumina七ed（FI：XISO，XIS2， XIS3）， with each is combined with an X−ray telescope（XRT）． The IR／UV blocking filters had accumulated a significant contamination by the time of the observation since its launch（July 2005）；we include its effects on the effec七ive area in our analysis． The XIS was operated with normal clocking mode， in 5×50r 3×3editing modes． The spaced−row charge injection（SCI）was not applied， and all the four CCDs were working at the time of the observation．
6．1．1 Surf5ce Brightness
To create Ancillary Response File（ARF）by feeding an image for analysis of S屹αえμ observations， we constructed surface brightness profiles ffom KBB model by Pratt＆
Arnaud（2002）．
6．1．2 Spectral Fitting
We used XSPEC version 12．4．Oy for all spectral丘tting． The FI and BI spectra were丘tted
simultaneously． We employed a祖αb5×αpec model for the ICM emission of the cluster as absorbed thermal plasma． The初αb5 component models七he photoelectric absorption
by the Milky Way， parameterized by the hydrogen column density that層was丘xed at the21cm value（Dickey＆Lockman 1990）． Theαpεc is a七hermal plasma mode1． Its fitting parameters are normalization，えT and the ICM abundance． The redshift was fixed at
七he optical spectroscopic value（z＝0．1427）． Additional fitting parameters are the twonormalizations and temperatures of the GAL components， and the normalization and
photon index of七he power−1aw model for the CXB component， as described previously．We did not丘t the ICM component in the outermost 20L 26／region because we can explain
87
88 σHAPTER 6． ANALYSlS AND RE8肌TS
the observed spectrum withou七it， as we show in figure C．4（e）． This situation was planned as we wanted to have an in−field measuremen七〇f the background． In figures C．2 and C．3，
we compared the intensities of the observed spectra minus the NXB to the spectra of the NXB and CXB components． Figure C．2（a）shows very strong Mn−Kαline at 5．9 keV from the 55Fe calibration source， therefore we ignored七he 5−7 keV energy band when we fit the FI spectrum of this annulus．
6．1．3 Results
In figure C．4， we show the best−fit spectra in each spa七ial region． These figures show the observed spectra after subtraction of七he NXB， as well as the best−fit． These figures show that individual spectra are well fi七ted by the model in each region． The normalization for 七he ICM component was fixed to zero in the 20L 26／annulus to estimate the background．
The ICM spectra did not show strong emission lines． Because of the low S／N ratio， i七was di伍cult to constrain the model parameters in the 15ノー20／annulus． Therefbre， we linked the ICM temperature and abundance in this region七〇七ha七〇f the region next interior to it，七he 10L 15 annulus． The best−fit parame七ers were consistent wi七hin the systematic errors for the two regions． The emission weighted average radius for the combined region
is 12 ．42±｝；：8今． −
Table 6．1 shows the best一丘t parameters for the ICM model in each region． We丘七一
ted with two difEerent solar abundances， namely Anders＆Grevesse（1989）and Feld−
man（1992）． The derived abundance values are higher when we adopt the Feldman（1992）
abundance， than the Anders＆Grevesse（1989）case， because the Fe abundance relative
to H in the former model is lower than the latter．In figure 6．1（a）， we show temperature profiles observed with Chandra（Vikhlinin et aL 2005），XM1匹Ne庇oη（Snowden et a1．2008）， and Suzaku（this work）． These profiles are consistent with each other in the range 7L 15 ． The Chandra七emperatures are about 20％
higher than the XMM−1Ve2〃￡oηvalues at 2ノ．7−7ノ． The tendency that Chandra gives higher
ternperature than XMM−1Veω君oηtypically becoming significant aboveんT〜5−6 keV is
pointed out in figure 120f Snowden et a1．（2008）． This discrepancy is due mainly to a Chandra calibration problem， namely the ground calibration of the HRMA effective area had some errors especially at the Ir edge（0．62 keV）， and there also was uncertainity about the IR／UV blocking filter contamination． These uncertainties caused a large discrepancybetween the Chandra and XMM−Ne庇oηmeasurements for high−temperature clusters．
Recent upda七es of the Chandra CALDB， HRMA AXEFEA version NOOO8，1 corrected most
of this discrepancy． However， there still remains some differences in clus七er temperatureby about 10％especially in hot objects． For七emperatures below〜5keV， Chandra and
XM］仏ノVe励oηre畢ults are mos七ly consistent with each other．We therefore used the X1匠M／Veωτoηtemperatures measured by Snowden et a1．（2008）．
In fact， their values are higher than those of Pratt＆Arnaud（2002）who used the same 1http：／／cxc．harvard．edu／ciao4．1／why／caldb4．1．1ユ1rma．html
6．ヱ． Aヱ4ヱ3 89
Table 6．1：Best fitting parameters of the spectral fits with 90％confidence errors fbr one
parameter．
2T−III（a）＊ 瓦T Abundance Norm§ S‖ X2／dof
（keV） （ZO）
2ノ．7−7ノ ．，．．．．．．．．． 7．03±｝歪1 0．44±8：器 16．35±｛：；9 5．77±8：鴉 77．4／107 7ノー10 ．．．．．．．．．．． 4．13±⑪：§1 0．54±81； 4．53±8：29 2．12±8：圭i｛ 98．7／116 10ノー15 ．．．．．．．．．，． 3．60±8：ζ； 0．39±8：；1 2．29±8：；§ 0．90±8：！§ 130．1／118 15 −20ノ ．．．．．．．，，．． ↑ ↑ 0．82±8：2 0．31±8：！6 109．5／116 20 −26 ．．．．．．．．．．． 一 ・ 一 一 一 152．7／113 Tbta1 ．．．．．．．．．．． 一 一 一 一 568．4／570
2T−III（b）† んT Abundance Noγm§ 811 ）（2／dof
（keV） （ZO）
2 ．7−7， ．．．．，．．．．．． 7．14±｝：！多 o．58±8：鋸 16．04±；：器 5．75±8：塁 77．1／107 7 −10 ．．．．．．．．．．． 4．41±8：琴； o．66±8：器 4．43±8：2書 2．11±8：易 1100．6／116 10 −15， ．．．．．．．．，．． 4．03±8：器 o．77±8：…！ 2．07±8：｝多 o．90±8：85 129．6／118
15，−20 ．．．．．．，．．．． ↑ ↑ o．72±8：器 o．31±8：器 114．7／116 20ノー26ノ ．．．，．．．．．．． 一 一 一 149．2／113 Tbta1 ．．．，．．．．．．． − 1 − 一 一 571．3／570
2T−III（c）‡ 瓦7「 Abundance Norm§ Sll ）〜／dof
（keV） （ZO）
2．7 −7ノ ．．．．．．．，．．． 7．20±｝：；8 0．43±8：；i 26．54±8：；； 9．41±9：1茎 76．7／105 7 −10 ．．．．．．，．．．． 4．33±8：％ 0．68±8：》； 11．02±8：96 5．44±8：器 99．8／114 10 −15ノ ．，．．．．．．．．． 3．97±8：§… o．53±8：》… 2．07±8：｝ o．89±8：89 125．2／116 15，−20 ．．．．．．．．，．． ↑ ↑ 0．66±8：6 0．34±8：81 104．3／114 20 −26 ．，．．，．．．．．． 一 一 一 一 154．5／113 Total ．．．．．．．．．．． 一 一 一 560．5／562
＊Abundance model is Anders＆Grevesse（1989）．
†Abundance model is Fbldman（1992）． ・
‡Including七wo gaussian models of OvlI and OvIII WHIM emission． Abundance model is Anders＆
Grevesse（1989）
§Normalization of the apec component scaled with a factor of 30乙促C百．孔4皿0．REG／Ω． in table 5．7，
N・・m＝SOmαD．田冗0ヱG／Ω。∫π。ηHdγ／（4π（1＋・）2D』）×1r2°cm−5 arcmin−2，wh・・e DA is the angular diameter distance七〇the source．
ll Surface brightness in unit of 10−6 photons cm−2 s−1 arcmin−2（0．4−10 keV）．
90 CHAPTER 6． ANALYS巧AND RE8 ULTS
Table 6．2：Same as table 6．1 except NXB土3％， CXBMAx and CXBMIN and contami土20％．
Abundance model is Anders＆Grevesse（1989）．
NXB−3％， CXBMIN んT Abundance JVoτm＊ S† X2／dof
（keV） （ZO）
2，．7−7， ．．．．．．．．．．． 7．57±｝：；§ 0．47±8：1！ 16．94±♀：；8 5．99±8：…1 78．7／107 7，−10， ．．．．．．．．．．． 4．84±と量 0．60±8：㌶ 4．91±8：認 2．34±8：麸 98．6／116 10，−15ノ ．．．．．．．．．．． 4．64±8：9至 0．51±8：…； 1．07±8：｝8 0．43±8：8参 130．6／116 15，−20， ．．．．．．．．．．． ↑ ↑ 0．98±8：圭9 0．41±8：86 114．2／116 20，−26ノ ．．．．．．．．．．． 一 一 一 157．1／115 Tot al ．．．．．．．．．．． 一 一 一 579．1／572
NXB十3％， CXBMAx えτ Abundance Norm＊ S† ）〈2／d6f
（keV） （ZO）
2 ．7−7， ．．．．．．．．．．． 6．60±圭：3ζ o．40±8：26 15．96±呈：認 5．51±8：§8 76．6／107 7ノー10ノ ．．．．．．．．．．． 3．59±8：62 0．53±8：iiζ 4．16±8：Z； 1．87±8：；茎 104．3／116 10ノー15， ．．．．．．．．．．． 2．52±8：§； o．35±8：｛6 2．14±8：；！ o．76±8：♀！ 130．3／116 15 −20 ．．．．．．．．．．． ↑ ↑ 0．53±8：｝8 0．18±8：86 118．6／116 20ノー26， ．．．．．．．．．．． 一 一 一 150．1／115 Tot a1 ．．．．．．．．．．． 一 一 579．9／572
con七ami十20％ んT Abundance IVorm＊ S† X2／dof
（keV） （Z◎）
2，．7−7， ．．．．．．．．．．． 6．89±｝：鵠 0．45±8：28 16．31±圭：；8 5．74±8：S 77．7／107 7，−10ノ ．．．．．．．．．．． 4．01±8：器 0．54±8：》言 4．54±8：i… 2．10±8：▲至 99．0／116 10，−15， ．．．．．．．．．．． 3．17±8：§｝ o．29±8：拝 2．41±8：発 o．90±8：呈6 131．3／118 15 −20 ．．．．．．．．．．． ↑ ↑ 0．84±8：彊 0．30±8：8； 109．6／116 20，−26 ．．．．．．．．．．． 一 一 一 一 153．4／113 Tot al ．．．．．．．．．．． 一 一 一 一 571．0／570
cont ami−20％ んT Abundance Norm＊ S† X2／dof
（keV） （ZO）
2 ．7−7 ．．．．．．．．．．． 7．08±｛：至§ o．42±8：ii8 16．36±！：§6 5．78±8：§9 77．4／107 7，−10 ．．．．．．．．．．． 4．19±8：器 0．54±8：；9 4．49±8：2； 2．11±8：號 99．0／116 10，−15， ．，．．．．．．．．． 3．82±8：；多 0．44±8：；9 2．21±8：芸 0．89±8：81 128．4／118 15ノー20， ．．．．．．．．．．． ↑ ↑ 0．79±8：▲8 0．31±8：86 109．1／116 20ノー26ノ ．．．．．．．．．．． 一 一 一 一 153．2／113 Tot a1 ．．．．．．．．．．． 一 一 567．1／570
＊Normalization of the apec component scaled with a factor of 30σR OE．R、42YO−REG／Ω． in table 5．7，
Normニ500R OE．R、4冗0−1ZEG／Ω，∫ηeπHdγ／（4π（1十z）2D』）×10−20 cm−5 arcmin−2， where DA is the angular diameter distance to the source．
†Surface brigh七ness in unit of 10−6 photons cm−2 s−1 arcmin−2（0．4−10 keV）．
6．1． ∠4L1413 91
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