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.)