1. X-ray observation of the Cygnus Loop with Suzaku and XMM-Newton
The X-ray Universe 2008, Granada, Spain
May 2008
Session: E.1+E.2: Planetary Nebulae, SN, SNR, Gamma-ray Bursts and Afterglows
Room: Andalucia I
Hiroshi Tsunemi1, Satoru Katsuda1,3, Hiroyuki Uchida1, Masaru Kimura1 and Koji Mori2
1Osaka university, Japan
2Miyazaki university, Japan
3NASA GSFC, US

2. The Cygnus Loop Talk plan Structure ISM abundance Ejecta abundance
ROSAT
- Location: (l, b) = (74 , ) - Distance： 540 pc, ⇒R=13.2 pc (Blair et al. 2005) - Age： ~1x104 yr, - SN Type: Core-collapse o o ~3 o
~26 pc
Rosat 衛星による白鳥座ループの X 線全体像。周囲が明るい典型的なシェル構造のSNR。
白鳥座ループは、銀河面から離れており、
かつ距離が 540 pc と大変近いため、低エネルギーのX線検出にはうってつけです。
この距離を使うと、視直径、3°は 26 pc になります。
年齢は、2 万年程度と見積もられており、セドフ期から放射冷却期に指しかかる天体と考えられている。
爆発のタイプは、Core-collapse と考えられている。 N W
Talk plan
Structure
ISM abundance
Ejecta abundance
ROSAT HRI image

3. CCD observations on the Loop The structure
The cold plasma surrounds the hot plasma
ASCA (Miyata et al., 1994, 1999)
NE rim and center
Chandra (Katsuda et al., 2008)
NE rim
Newton (Green circles)
(Tsunemi et al., 2007, Nemes et al., 2007)
NE to SW, South (Uchida et al., 2008)
Suzaku (Squares)
(Katsuda et al., 2007, Miyata et al., 2007)
NE rim, NE to SW North, South and going on

4. Cygnus Loop
We divided the north path and the south path. They are divided into many small sectors: 141 in the north path and 172 in the south path. These small annular sectors contain similar statistics (~20,000 for MOS1/2 and ~40,000 for PN). (Tsunemi et al., 2007)

5. Example spectra Northeastern rim Center kTe: 0.17 ± 0.01keV
High-T component
Low-T component PN PN
MOS1, 2 O7
Fe 17 O7
Fe 17 O8
Ne 9 O8
Mg 11
Ne 9
Mg 11
Si 13
This is the spectrum from the northeastern region and this is the spectrum from the central region. We can see the emission lines from these ions. We can see very strong emission line of Si13 in the spectrum of center portion. The electron temperature of northeastern rim is significantly lower than that in the center portion. The spectrum from the northeastern rim is relatively well fitted by a single temperature NEI model whereas that in the center portion is not. Therefore, we applied two-temperature component NEI model for the spectrum in the center portion.
kTe: 0.17 ± 0.01keV
L-kTe: 0.17 ± 0.01keV H-kTe: 0.53± 0.02keV
We applied a 2 kTe-component NEI model for the spectrum in the center portion.

6. Is Two-kT model really needed?
One-kT model vs two-kT model
One-kT model vs two-kT model

7. 2 kTe-component model Center
High-T component
Low-T component
The best-fit two temperature component model is shown here. The two temperature component model significantly improves the fit. The temperatures of the two components are about 0.2 keV and 0.5 keV, respectively. The temperature of the low temperature component is similar to that in the northeastern rim. Therefore, we considered that the low temperature component surrounds the high temperature component like this. We fitted all the spectra by 2 temperature-component model. In this model, the free parameters are kTe and ionization time and normalization for both components and abundances of high temperature components. Abundances of the low temperature component are fixed to the best-fit values determined by the fitting of the spectrum from these edge regions. From the statistical point of view, these regions are fitted by a 2 temperature-component model rather than a single temperature component model. The boundary is located around 90 % of the shock radius.
We fitted all the spectra by 2-kTe component model. Free parameters: Low-T: kTe, net, Norm High-T: kTe, net, Norm, abundances
Low-T: kTe ~ 0.2 keV High-T: kTe ~ 0.5 keV

8. 2 kTe-component model Center High-T Low-T
High-T component
Low-T component
The best-fit two temperature component model is shown here. The two temperature component model significantly improves the fit. The temperatures of the two components are about 0.2 keV and 0.5 keV, respectively. The temperature of the low temperature component is similar to that in the northeastern rim. Therefore, we considered that the low temperature component surrounds the high temperature component like this. We fitted all the spectra by 2 temperature-component model. In this model, the free parameters are kTe and ionization time and normalization for both components and abundances of high temperature components. Abundances of the low temperature component are fixed to the best-fit values determined by the fitting of the spectrum from these edge regions. From the statistical point of view, these regions are fitted by a 2 temperature-component model rather than a single temperature component model. The boundary is located around 90 % of the shock radius.
We fitted all the spectra by 2-kTe component model. Free parameters: Low-T: kTe, net, Norm High-T: kTe, net, Norm, abundances
Low-T: kTe ~ 0.2 keV High-T: kTe ~ 0.5 keV

9. Temperature distributions of the two components as a function of position. Filled circles show the ejecta component, while crosses show the cavity component. Black show the north path and red shows the south path.
×　cavity component
●　ejecta component

10. Cygnus Loop
We divided the north path and the south path. They are divided into many small sectors: 141 in the north path and 172 in the south path. These small annular sectors contain similar statistics (~20,000 for MOS1/2 and ~40,000 for PN). (Tsunemi et al., 2007)

11. Intensity correlation between XMM-Newton and ROSAT
XMM total

12. Intensity correlation between XMM-Newton and ROSAT
XMM total = XMM Low-T + XMM High-T

13. Flux distributions of the two components as a function of position
Flux distributions of the two components as a function of position. Filled circles show the ejecta component, while crosses show the cavity component. Black show the north path and red shows the south path.
×　cavity component
●　ejecta component
Ejecta exceeds ISM

14. Cygnus Loop ROSAT HRI image
This is the ROSAT HRI image of the entire Cygnus Loop. The Cygnus Loop is one of proto-typical shell-type SNRs. The distance is so close to us that the apparent size is very large. The age is estimated to be ~20000 years old. We observed the Cygnus Loop from northeastern rim to southwestern rim using XMM-Newton observatory. The XMM-Newton image is shown here.
ROSAT HRI image

15. Cygnus Loop ROSAT HRI image
This is the ROSAT HRI image of the entire Cygnus Loop. The Cygnus Loop is one of proto-typical shell-type SNRs. The distance is so close to us that the apparent size is very large. The age is estimated to be ~20000 years old. We observed the Cygnus Loop from northeastern rim to southwestern rim using XMM-Newton observatory. The XMM-Newton image is shown here.
ROSAT HRI image

16. South break-out region See E9 (Uchida et al.)

18. CCD observations on the Loop Abundance of the ISM
The cold plasma is metal deficient very much.
ASCA (Miyata et al., 1994, 1999)
NE rim and center
Chandra (Katsuda et al., 2008)
NE rim
Newton (Green circles)
(Tsunemi et al., 2007, Nemes et al., 2007)
NE to SW, South (Uchida et al., 2008)
Suzaku (Squares)
(Katsuda et al., 2007, Miyata et al., 2007)
NE rim, NE to SW North, South and going on

19. Spatially Resolved Spectral Analysis for NE-rim Regions
Non-Equilibrium Ionization (NEI) model.
北東領域について、すざくの視野をこのように細かく区切ってスペクトル解析をしました。
一つの領域からのスペクトルをこちらに示しました。
得られたスペクトルを単一温度の電離非平衡プラズマモデルでフィットしました。
このモデルですべてのスペクトルは良くフィットでき、
典型的な温度は0.25 keV程度, 電離度は、1E11 程度と電離非平衡であることが判りました。
=> Single component model can represent the data very well. kTe : ~ 0.25 keV , t : ~1x1011cm-3 sec

20. Metal-abundances @ NE-rim
Metal abundance (relative to the solar values)
C/H: ~0.27 N/H: ~0.10 O/H: ~0.11 Ne/H: ~0.21 Mg/H: ~0.17 Si/H: ~0.34 S/H: ~0.16 Fe/H: ~0.20
All are sub-solar
⇒ ISM origin rather than ejecta origin
スペクトル解析から、この領域の平均アバンダンスを測定しました。
CNONeMgSiSFe について、太陽組成と比較した値ですが、全て太陽組成に比べて deplete していることが判りました。
このことからこの領域のプラズマの起源は、ショックによって掃き集められた星間物質であることを確認しました。
Optical data in the direction of the Cygnus Loop shows sub-solar (O/H ~ 0.4).

21. Is ISM around the Cygnus Loop metal poor?
Model fitting shows the metal deficient C~0.27、N~0.1、O~0.1 (Katsuda et al., 2007)
Optical data in the direction of the Loop indicates the metal poor (O~0.4) (Cartledge et al., 2004)
Non-thermal component may reduce the apparent metal abundance. Fit is not improved by adding a simple power law component.
Some area in the NE rim shows normal metal abundance (O=0.5). This may show a pure ISM component. (Katsuda et al., 2007)
⇒It may really metal deficient; less than that of the ISM there.
⇒Model is too simple.
1897/1208

22. Thin thermal with ISM abundance + Power spectrum ?
Γ= 1
Γ= 2
2018/1208
2017/1208
Γ= 4
Γ= 3
2032/1208
1998/1208

23. CCD observations on the Loop
ASCA (Miyata et al., 1994, 1999)
NE rim and center
Chandra (Katsuda et al., 2008)
NE rim
Newton (Green circles)
(Tsunemi et al., 2007, Nemes et al., 2007)
NE to SW, South (Uchida et al., 2008)
Suzaku (Squares)
(Katsuda et al., 2007, Miyata et al., 2007)
NE rim, NE to SW North, South and going on

24. Abundance maps O N Ne C S Fe Mg Si Mean: ~0.27 Mass: ~5x10-3
Small region in the NE rim shows higher abundance than the surrounding area.
Suzaku and Chandra

25. NE rim in the Loop has two kinds of plasma : normal abundance plasma and metal deficient plasma Katsuda et al., 2007
Normal metal abundance (O～0.5) Metal poor abundance (O ～ 0.1)

27. CCD observations on the Loop Abundance of the ejecta
The hot plasma is directly seen where there is no cold plasma.
ASCA (Miyata et al., 1994, 1999)
NE rim and center
Chandra (Katsuda et al., 2008)
NE rim
Newton (Green circles)
(Tsunemi et al., 2007, Nemes et al., 2007)
NE to SW, South (Uchida et al., 2008)
Suzaku (Squares)
(Katsuda et al., 2007, Miyata et al., 2007)
NE rim, NE to SW North, South and going on

28. Suzaku Observations Suzaku Suzaku Suzaku image (0.2-3 keV)
今回、我々は、白鳥座ループ中に広がる爆発噴出物の分布を調べるため、
すざく衛星で北東端から南西端にかけてこのように観測しました。
こちらがすざくで得たX線画像です。観測日は、2005 年 11 月と、昨年 5 月です。
総観測時間は、186 ksec と大変大きな観測です。
Suzaku image (0.2-3 keV)
Obs. date： 23/11/2005 ~ 25/05/2006
Suzaku FOV overlaid on the ROSAT HRI image
Total exposure time： ~186 ksec

29. Asymmetric Distributions of Metal rich ejecta
Mg ~3
Ne ~3
S ~20
Si ~10
Fe ~15
イジェクタ成分の O, Ne Mg Si S Fe の分布図を描きました。
ここが SNR 中心ですが、中心に対してどの元素も非対称に分布していることが判りました。
特に、SiSFe といった重い元素については、南部でより多くのイジェクタが分布することが判りました。
これは、爆発の際の噴出物の非対称を反映しているのではないかと考えられます。
また、この視野内の噴出物の総質量は、約 1.8 M◎と見積もりました。

31. Summary
The Cygnus Loop show double structures; swept-up cavity material and metal rich ejecta.
Low-T component (cavity wall matter)
Low-kT component surrounds the Loop with various thickness. The abundance is metal deficient. This may be due to the non-thermal component usually seen in the young SNR.
Major part of the Loop is surrounded by a cavity wall material. The south blow-up region clearly shows very thin wall. There is also a very thin wall in the central part of the Loop. This must be a blow-up region either in the near side or in the far side.
A various type of plasma condition is seen in the cavity wall plasma.
High-T component (fossil material of explosion ejecta)
High kT component shows high metal abundance. The spreads of Ne, Mg, Si, S and Fe are considered to represent the onion-skin structure at the time of SN explosion, suggesting significant convection has not occurred yet.
Comparing the relative abundances obtained from our data with those from theoretical calculation for type-II SN, the mass of the progenitor star is likely to be ~15M◎.
High T component extends to the south (X-ray data did not show the second SNR) . It also extends to the outer side in the middle of the Loop.
This is a summary of the XMM-Newton observations of the Cygnus Loop.

32. EM of the ejecta components