I. Origin of the dust emission from Tycho’s SNR
II. Mapping observations of [Fe II] lines and dust emission of IC443 by IRSF & AKARI
III. Summary
AKARI infrared observations of SNRsIshihara Daisuke (Nagoya Univ.)
I. Origin of the dust emission from Tycho’s SNR
Ishihara, D., et al. 2010
- Observed in 1572 by Tycho Brahe
- Type Ia
- Distance = 1.5 ~ 3.1 kpc
- Detection of IR emissioin + IRAS (Schwaltz 1995)
+ ISO/ISOCAM (Douvion+ 2001)
- Size = 8’ (5.3pc)- Extensively studied in X-ray,
Radio and Optical
Tycho’s SNR
- Observed in 1572 by Tycho Brahe
- Type Ia
- Distance = 1.5 ~ 3.1 kpc
- Detection of IR emissioin + IRAS (Schwaltz 1995)
+ ISO/ISOCAM (Douvion+ 2001)
- Size = 8’ (5.3pc)- Extensively studied in X-ray,
Radio and Optical
Tycho’s SNR
1. Tycho’s SNR - introduction
(Warren+ 2005)
4.1 -6.1 keV 1.63-2.26 keV 0.95-1.26 keV,
1. Tycho’s SNR - introduction
Fastexpansion(0.45”/yr)
Slowexpansion(0.15”/yr)
X-ray (Suzaku 0.1-12 keV)Molecular cloud (12CO)
Hot dust (AKARI 18um)
Expansion velocity from VLA 1375 Hz (Reynoso+ 1997)
- Observed in 1572 by Tycho Brahe
- Type Ia
- Distance = 1.5 ~ 3.1 kpc
- Detection of IR emissioin + IRAS (Schwaltz 1995)
+ ISO/ISOCAM (Douvion+ 2001)
- Size = 8’ (5.3pc)- Extensively studied in X-ray,
Radio and Optical
Tycho’s SNR
2. AKARI infrared observations
X-ray (Suzaku 0.1-12 keV)Molecular cloud (12CO)
Hot dust (AKARI 18um)
Expansion velocity from VLA 1375 Hz (Reynoso+ 1997)
- Observed in 1572 by Tycho Brahe
- Type Ia
- Distance = 1.5 ~ 3.1 kpc
- Detection of IR emissioin + IRAS (Schwaltz 1995)
+ ISO/ISOCAM (Douvion+ 2001)
- Size = 8’ (5.3pc)- Extensively studied in X-ray,
Radio and Optical
Tycho’s SNR
We investigated physical state and origin of the MIR emissionusing AKARI (9, 15, 18, 24, 65, 90, 140, 160um) images.
Flu
x (J
y)
Infrared SED of dust emission
3. Overall pictureF
lux
(Jy)
Total SED (AKARI+IRAS) is characterized by two temperatures
Dust temperature ⇒ higher at outer edge (shock front)
MIR map limb-brightened shell structure
⇒ Shock heated dust of IS origin
Infrared SED of dust emission
15/24mm intensity ratioAKARI 9mm band AKARI 18mm band
0.2 0.3
(100 ~ 136 K)(PAH) (Hot dust)
T1 ~ 25 K
ISMT2 ~ 95 K
Shock heated
dust
⇒150 yr⇔ 500 yr (Age of the SNR)
(Draine & Salpeter 1979, Tielens et al. 1994)
Time scale of the dust destruction by sputtering in hot plasma
Time scale of PAH destruction is1/100 ~ 1/1000 faster
⇒ < 1 yr . . . vanished
C=0.79 (silicate), a=1nm, T=8.4x10 K 、 nH=10 cm
6 -3
Flu
x (J
y)
Infrared SED of dust emission
15/24mm intensity ratioAKARI 9mm band AKARI 18mm band
0.2 0.3
(100 ~ 136 K)(PAH) (Hot dust)
⇒150 yr⇔ 500 yr (Age of the SNR)
(Draine & Salpeter 1979, Tielens et al. 1994)
Time scale of the dust destruction by sputtering in hot plasma
Time scale of PAH destruction is1/100 ~ 1/1000 faster
⇒ < 1 yr . . . vanished
C=0.79 (silicate), a=1nm, T=8.4x10 K 、 nH=10 cm
6 -3
3. Overall picture
T1 ~ 25 K
ISMT2 ~ 95 K
Shock heated
dust
150 yr500 yr
atom
ISM dust is heated at the shock front and destructed by the sputtering in the post-shock hot-plasma Shell structure of ⇒ ~ 100 K
Flu
x (J
y)
Infrared SED of dust emission
15/24mm intensity ratioAKARI 9mm band AKARI 18mm band
0.2 0.3
(100 ~ 136 K)(PAH) (Hot dust)
C=0.79 (silicate), a=1nm, T=8.4x10 K 、 nH=10 cm ⇒150 yr⇔ 500 yr (Age of the SNR)
(Draine & Salpeter 1979, Tielens et al. 1994)
Time scale of the dust destruction by sputtering in hot plasma
Time scale of PAH destruction is1/100 ~ 1/1000 shorter
⇒ < 1 yr . . . vanished
6 -3
3. Overall picture
ISM dust is heated at the shock front and destructed by the sputtering in the post-shock hot-plasma Shell structure of ⇒ ~ 100 K
We focus on the two bright spots at NE and NW boundaries.
NE NW
- Large amount of cold dust at NE
Spatial distribution of molecular gas, cold dust
⇒ SNR is interacting with dense medium at NE boundary
⇒ NW is relatively rich in warm dust compared with amount of molecular gas
NE NW
Hot dust
Gas (H2) 2M20M
2x10 M- 4
10 4 10 5
2x10 M- 4
-60 ~ -63 km/s
~ 100 KRatio
Gas/dust
AKARI(cold dust)
AKARI(cold dust)
Flu
x (J
y)
NE NW
Infrared SED of dust emission
Local SED for NE region
4.1. Origin of NE and NW emission
Ejecta origin
ISM origin
⇒ The NW warm dust could have an SN ejecta origin
AKARI 18μm intensity mapー Blast waveー Conduct discontinuity (Warren+ 2008)
ContactdiscontinuityBlast wave
ColdISM
HeatedISM
Ejectafrom SNR
Schematic view around blast wave
4.2. Origin of dust emission at NW boundary
- Featureless continuum(No lines, dust features)
- Composed of pure Fe?
Image : AKARI mid-IR (15μm)Contour: Hα
Spitzer / IRS 5~36μm spectrum
IRS spectrum of Cas A (Rho+ 2008)
4.3. Composition of newly formed dusts
• Infrared observations of Tycho’s SNR(AKARI 9-160μm)⇒ Physical state (temperature, heating source) and origin of hot dusts
• Overall picture: Dusts of an ISM origin are heated and destroyed in the hot plasma
• NE region: Interaction with dense ISM• NW region: Hot dusts without dense ISM
- small gas/hot dust mass ratio- located inside the contact discontinuity ⇒ SN ejecta origin ?
• First suggestion of dust formation in Type Ia SNR → impact on the transmigration of the ISM in our galaxy and early universe.• Demonstrates advantage of AKARI diffuse maps
combined with X-ray and 12CO maps.
5. Summary
II. Mapping observations of [Fe II] lines and dust emission of IC443 by IRSF & AKARI
Kokusho, T., et al. in prep.
1. Introduction□ IC443
- Type II (Troja+ 2008)
- Distance: ~1.5 kpc- Size: 45 amin (20 pc)- Age: ~104 yr- Heavy interaction with the ISM (Saken+ 1992)
- Over-ionized X-ray plasma Center-filled, rapid cooling? (Kawasaki+ 2002)
- [Fe II] line emission in NE part of the remnant → J-shock (Graham+ 1987)
- H2 line emission in south part of the remnant → C-shock (Rho+ 2001)
IC443 Hα image
30’
Saken+1992
1. Introduction□ IC443
- Type II (Troja+ 2008)
- Distance: ~1.5 kpc- Size: 45 amin (20 pc)- Age: ~104 yr- Heavy interaction with the ISM (Saken+ 1992)
- Over-ionized X-ray plasma Center-filled, rapid cooling? (Kawasaki+ 2002)
- [Fe II] line emission in NE part of the remnant → J-shock (Graham+ 1987)
- H2 line emission in south part of the remnant → C-shock (Rho+ 2001)
IC443 IRAS 100μm image
1. Introduction□ IC443
- Type II (Troja+ 2008)
- Distance: ~1.5 kpc- Size: 45 amin (20 pc)- Age: ~104 yr- Heavy interaction with the ISM (Saken+ 1992)
- Over-ionized X-ray plasma Center-filled, rapid cooling? (Kawasaki+ 2002)
- [Fe II] line emission in NE part of the remnant → J-shock (Graham+ 1987)
- H2 line emission in south part of the remnant → C-shock (Rho+ 2001)
IC443 ASCA 0.7-10 keV image
30’
Contours: softness ratio(Kawasaki+ 2002)
1. Introduction□ IC443
- Type II (Troja+ 2008)
- Distance: ~1.5 kpc- Size: 45 amin (20 pc)- Age: ~104 yr- Heavy interaction with the ISM (Saken+ 1992)
- Over-ionized X-ray plasma Center-filled, rapid cooling? (Kawasaki+ 2002)
- [Fe II] line emission in NE part of the remnant → J-shock (Graham+ 1987)
- H2 line emission in south part of the remnant → C-shock (Rho+ 2001)
IC443 2MASS imageBlue: J, green: H, red: Ks-band(blue; [Fe II],Pβ, red: H2)
1. Introduction□ IC443
- Type II (Troja+ 2008)
- Distance: ~1.5 kpc- Size: 45 amin (20 pc)- Age: ~104 yr- Heavy interaction with the ISM (Saken+ 1992)
- Over-ionized X-ray plasma Center-filled, rapid cooling? (Kawasaki+ 2002)
- [Fe II] line emission in NE part of the remnant → J-shock (Graham+ 1987)
- H2 line emission in south part of the remnant →C-shock (Rho+ 2001)
IC443 2MASS imageBlue: J, green: H, red: Ks-band(blue; [Fe II],Pβ, red: H2)
Based on observations of [Fe II] line emissions and IR dust emissions,we discuss on supply of Fe element from SNRs to the ISM.
2. FIR images from AKARI all-sky survey65mm 90mm
140mm 160mm
90MJy/sr 110MJy/sr
240MJy/sr 300MJy/srl
65 90 140160
dust
[CII][OI]
2. FIR images from AKARI all-sky survey90mm
140mm
110MJy/sr
240MJy/srl
65 90 140160
dust
[CII][OI]
[OI]
[CII]
Contours: 140mm
2. FIR images from AKARI all-sky survey90mm
140mm
110MJy/sr
240MJy/srl
65 90 140160
dust
[CII][OI]
[OI]
[CII]
Contours: 140mm
AKARI 2.5 – 5 mm spectra
2. FIR images from AKARI all-sky survey65mm
160mm
90MJy/sr
300MJy/sr
90mm
140mm
110MJy/sr
240MJy/srl
65 90 140160
dust
[CII][OI]
2. FIR images from AKARI all-sky survey65mm
160mm
90MJy/sr
300MJy/sr
90mm
140mm
110MJy/sr
240MJy/srl
65 90 140160
dust
[CII][OI]
Broad bands tracing dust emissionwith small contribution of [OI] 63μm and [CII] 158μm line emissions.
→ Derive hot-dust mass distribution by fitting dust SEDs composed of Spitzer 24μm, AKARI 90μm, and 140μm intensities.
3. Observations of [Fe II] lines
[Fe II] 1.256μm : 4D7/2 → 6D9/2
[Fe II] 1.644μm : 4D7/2 → 4F9/2
Transitions from same level.→ The intensity ratio is theoretically derived from Einstein A-coeffs. (Narayan+ 2010)
→ Accurate Av correction
→ Av-free [Fe II] intensityNarrow-band filters for
[Fe II] 1.256μm & 1.644μm
IRSF telescope of Nagoya Univ.(at South Africa)Nagayama+ 2008
(μm)
(%)
J H
1.256 1.644
Pβ
3. Origin of [Fe II] emission
• ISM: ~98 % of Fe is depleted on dust grains[Fe II] 1.64μm / Brγ ~1
• SNRs: Fast shocks (~100 km/s)
⇒ destruction of dust grains [Fe II]1.64μm / Brγ~100 (Koo+ 2007)
• [Fe II] IP: 7.9 eV (< 13.6 eV)
• In equilibrium hot plasma (T=107K),most of Fe is Fe20+
no Fe1+
→ Tracers of fast shocks, young SNRs
(Mazzotta+ 1998)
atom
3. [Fe II] distribution
IRSF[Fe II] 1.256μm
IRSF[Fe II] 1.644μm
→ Derive Fe mass distribution from Av-free [Fe II] intensities assuming LTE with T~104 K.
(erg/s/cm2/sr)
2MASS J, H, Ks
3. [Fe II] distribution
[Fe II]1.644μmContours: Hα + [NII] AKARI 18μm
(hot dust)
AKARI 9μm(PAH, H2 lines)
atom
→ Mdust
4. Comparison of dust mass and Fe mass
□ Dust mass related to the SNR
□ Fe+ mass
SED fitting by 2 temp. B.B.
- Hot dust … shock heated- Cold dust … (foreground or background ?)
Hot dustcomponent
assuming, a=0.1μm, Qabs=30cm2g-
1
(Hildebrand 1983)
(μm)
MFe = N ・ (unit mass)
4. Discussion
Fe / hot dust mass ratio
10’
- Fe / hot dust mass ratio shows excess in some regions.
Solar abundance ~ 0.4
(excess amount ~106 Msun)
Dust mass Fe+ mass
AKARI IR SED IRSF [Fe II]
4. Comparison of time scales
Fe1+ disappears at ionization equilibrium (Te=107K)
□ Life time of dust grains in hot plasma:
□ Time scale to reach ionization equilibrium :
(Darine+ 1979)
In the hot plasma of Te=107, ne=1.7 cm-1, adust=0.1μm (Yamaguchi+ 2009, Petre+ 1988)
(yr) (Masai 1994)
⇒ ~ 1x105 yr
⇒ ~ 2x104 yr
→ [Fe II] line emissions attenuate faster than IR dust emission.
4. Discussion
Fe / hot dust mass ratio
10’
⇒ Fe ejected from SNR ?
- Fe / hot dust mass ratio shows excess in some regions.
Solar abundance ~ 0.4
(excess amount ~106 Msun)
Dust mass Fe+ mass
AKARI IR SED IRSF [Fe II]
- [Fe II] line emissions attenuate faster than IR dust emission.
5. Summary
• AKARI mid-& far-infrared & IRSF near-IR observation of IC443
• Northern region: [Fe II] originated by dust sputtering in J-shock
• Southern region: H2 and [O I] in C-shock
• Accurate correction of extinction by observing two [Fe II] lines
• Fe+ / hot dust mass ratio shows excessin some parts of IC443→ [Fe II] line emissions attenuate faster than IR dust emission→ Fe of an SN ejecta origin ?
III. Summary
• Interaction of SNRs with the dense ISM→ IR observations
• Fe in ejecta of SNRsTycho’s SNR (10-4 Msun) … Type IaIC443 (10-6 Msun) … Type II
• Utilization of AKARI All-Sky diffuse maps(shock tracer, past shock tracer, as well as indicators of dust temperature, dust mass, etc.)