Detecting Cool Dust in SNRs
in LMC and SMC with ALMA
Takaya Nozawa (Kavli IPMU)
andMasaomi Tanaka (NAOJ)
Targets
・ SN 1987A: our proposal for ALMA Cycle 0and next plan for ALMA Cycle 1
・ 1E0102.2-7219: youngest SNR in SMC
2012/6/11

1. SNRs at submm and millimeter wavelengths
・ molecular lines and synchrotron emission
from interaction regions between molecular
clouds and SN blast waves

・ synchrotron emission frompulsar wind nebulae・ thermal emission from cool dust which wasformed in the expanding ejecta of SNe➔ cool dust dominates the dust mass
➔ discovery of a huge amount of dust at z > 5

SNe are important sources of interstellar dust?

2. Summary of dust mass in core-collapse SNecool dust in SN1987A
theorymissing cold dust?

young SNRs

swept-up IS dust?
young SNeFar-IR to sub-mm observations are essential for revealing
the mass of dust grains produced in the ejecta of SNe

3. Herschel detects cool dust in SN 1987A
Matsuura et al. 2011

Herschel detects cool (~20K)
dust of ~0.4-0.7 Msun toward
SN 1987A!

4. Resolving cool dust in SN 1987A with ALMA
ALMA Cycle 0 Proposal‘Detecting cool dust in SN1987A’Band 7 (850 μm)

Band 9 (450 μm)（TN, Tanaka, et al.)2 arcsec

CASA simulation
with extended
config. (4 hrs)

0.1 Msun of silicate➔ 5σ detection at Band 9 !!

5. Constraining mass of cool dust in SN 1987A
Herschel results had not yet
opened at that time …

Lakicevic+12, A&A, 541, L1
3 mm

If detected with 2.7 mJy, morethan 0.06 Msun of grains exist !!

Lakicevic+12, A&A, 541, L2

6. Successful ALMA proposals for SN 1987AThis proposal was ranked
in the highest priority, tobe observed this fall !!

Band 9extended configuration

Band 3, 6, 7, 9
compact configuration

7. Condition of atmosphere
BandBand 3

Band 6

Band 7

Band 9Fraction

100%

70%

40%

10%

LMC

From ALMA Cycle 1 proposer’s guide8. 12m-array configurations for ALMA Cycle1
compact

Cycle0 proposal(extended, Band 9)
Ang Res : 0.23”
Max Res : 1.5”extended

Cycle1 proposal
・ Band 6, 7, and 9
・ C32-5 or C32-6 ormixed confguration?

9. Possible target: SNR 1E0102, a twin of Cas A
24 μm

X-ray, radio

・ SNR 1E0102－ O-rich (Type Ib?)
－ age : ~1000 yr－ Mwarm ~ 10-3 Msun
－ Mcool ~ ???
Stanimirovic+05
24 μm

Gaetz+00

100 μm・ Cassiopeia A－ Type IIb－ age : 330 yr－ Mwarm < 10-2 Msun
－ Mcool ~ 0.07 Msun
Cas A model (Nozawa+10)
Barlow+10, A&A, 518, L138

10. IR observations of SNR 1E0102
24 μm

70 μm

Spitzer; Stanimirovic+05

・ SNR 1E0102 in SMC－ age : ~1000 yr
youngest CCSNe－ diameter : ~40”(= 12 pc @ 60 kpc)
－ similar to Cas A
・ hot dust mass
－ Mwarm = 8x10-4 Msun
(Stanimirovic+05)－ Mwarm = 0.014 Msun
Mwarm = 3x10-3 Msun

(Rho+09)・ cool dust mass
－ Mcool < 0.6 Msun
with Tdust = 20-30 K
Sandstrom+09, ApJ, 696, 2138

(Sandstrom+09)

11. Comparison with SED of SN 1987A
IR SED of SN 1987A

IR SED of SNR 1E0102

Cycle 1
1 sigma, 1 hr

IR-to-radio SEDs of SN 1987A and 1E0102 are similar

But ..

12. SNR 1E0102 is too extended!

SN 1987A

40 arcsec

13. Array & ACA combinations

・ Use of ACA requires 3 times more times
・ Atmospheric correction is not available on ACA・ Total Power (TP) is not available for continuum14. What is the best strategy for SNR 1E0102?
Band 3 with ACA
Band 3

Band 9 with ACA

SN 1987A

40 arcsec

15. Flux estimates necessary for detection
1987A
Band 9

1E0102
Band 9full operation
1 sigma, 1 hr

effective flux
(flux per beam)16. Summary
Detecting cool dust in SNRs with ALMA・ SN 1987A (radius: 0.5 arcsec)－ Spatially resolved images in Band 6, 7, and 9－ Possibility of detecting molecular lines?

・ 1E0102.2-7219 (radius: 20 arcsec)－ too large and too faint (almost impossible)➔ it seems too hard to detect continuum emission
from cool dust in any other SNRs..

A-1. How dense is cool dust in 1E0102?
・ 1E0102.2-7219
R = 15 arcsec ➔ 1.3x1019 cm = 4.4 pc @ 60 kpc
what is the mass of dust if ISM dust is includedin the sphere with this radius?
Mdust ~ (4πR3 / 3) D (nH mH)= 0.077 Msun (D / 0.01) (nH / 1 cm-3)
・ Cassiopeia A
R = 100 arcsec ➔ 4.8x1018 cm = 1.6 pc @ 3.4 kpc

A-2. Importance of molecular lines in SN 1987A
・ CO and SiO molecules were detected around 300 days
after explosion in SN 1987A(CO and SiO were confirmed in many dust-forming SNe)・ Measuring the expansion velocity of the ejecta
・ CO molecule has been detected in Cas A SNR・ All condensible metals have to be tied up in dust grains
to explain 0.4-0.7 Msun of dust in SN 1987A➔ CO and SiO molecules can survive??

・ How much CO and SiO line fluxes can contribute thecontinuum flux?
➔ expected mass of CO and SiO: ~10-3 Msun

A-3. Summary of molecular lines
Band 3: 84-115 GHz
Band 6: 211-274 GHz
Band 7: 275-373 GHz
Band 9: 607-720 GHz

・ CO molecule・ SiO moleculeν=0, 1-0: 115.271 GHz (B3)ν=0, 2-1: 230.538 GHz (B6)ν=0, 3-2: 345.796 GHz (B7)ν=0, 4-3: 461.041 GHz
ν=0, 5-4: 576.268 GHz
ν=0, 6-5: 691.473 GHz (B9)ν=0, 2-1: 86.847 GHz (B3)ν=0, 3-2: 130.269 GHz
ν=0, 4-3: 173.688 GHz
ν=0, 5-4: 217.105 GHz (B6)ν=0, 6-5: 260.518 GHz (B6)ν=0, 7-6: 303.927 GHz (B7)ν=0, 8-7: 347.331 GHz (B7)ν=0, 15-14: 650.958 GHz (B9)ν=0, 16-15: 694.296 GHz (B9)