2015/03/26

Detecting Cool Dust in Type Ia
Supernova Remnant 0509-67.5(ranked as priority grade B for ALMA Cycle2)

Takaya Nozawa (NAOJ, 理論研究部)
andMasaomi Tanaka (NAOJ, 理論研究部)

1-1. Introduction
Supernovae (SNe) are main sources of interstellar dust?
‐a large amount of dust grains (>108 Msun) are detected in hostgalaxies of quasars at redshift z > 5➜ SNe must have play a dominant role as sources of dust
➜ more than 0.1 Msun of dust per SN is needed to be ejectedto explain such massive dust at high-z (Dwek+2007)‐SNe must be primary dust sources even in the present universe➜ comparable contribution with AGB stars (Dwek & Scalo 1980)n(AGB stars) / n(SNe) ~ 10-20

Mdust = 0.01-0.05 Msun per AGB (Zhukovska & Gail 2008)
Mdust = 0.1-1.0 Msun per SN (Todini & Ferrara 2001; Nozawa+2003; 2007)

Dust formation in SNe is a key to disclose the origin
and evolution of dust throughout the cosmic age

1-2. Summary of observed dust mass in CCSNe

missing cold dust?

young SNRs

Matsuura+2011

supernovae

Balow+2010

Gomez+2012

swept-up IS dust?

Far-IR to sub-mm observations are essential for revealing
the mass of dust grains produced in the ejecta of SNe

1-3. Herschel detects cool dust in SN 1987A
SED of 23-years old SN 1987A~180K~10-5 Msun
~20K~0.5 Msun

Matsuura+11Herschel detected cool (~20K) dustof ~0.4-0.7 Msun toward SN 1987A➔ SNe are production factoriesof massive dust grains

1-4. Resolving cool dust in SN 87A 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 extendedconfig. (4 hrs)

0.1 Msun of silicate➔ 5σ detection at Band 9

1-5. ALMA reveals dust formed in SN 1987A‐Detecting Cool Dust in SN 1987A ➜ not executed(Nozawa, Tanaka, Moriya, Minamidani, Kozasa)

Band 9, extended configuration‐SN87A: A Unique Laboratory for Shock and Dust Physics(Indebetow, McCray, Matsuura, + 27 coauthors)Band 3, 6, 7, and 9, compact configuration

Indebetouw+2014

CASA simulation
by Tanaka, T.

ALMA confirmed ~0.5 Msun ofdust formed in the ejecta

1-6. Our status for ALMA Cycle1 proposal‐Detecting Cool Dust in SN 1987A ➜ failed(Tanaka, Nozawa, Moriya, Minamidani, Kozasa)

Band 7 and 9‐SN 1987A: A Unique Laboratory of Shock, Molecular and DustPhysics➜ succeeded(Indebetow, McCray, Matsuura, + 22 coauthors)

・ SN 1987A: the best target to detect cool dust formed in the ejecta‐nearest SN ever observed (in LMC)
‐young (~27 yr) and compact (~2” in diameter)・ other candidates‐extragalactic SNe (D >~5 Mpc) ➔ too distant (too faint)‐Galactic SNRs (d >~1’) ➔ too old (too extended)

SNe and SNRs in LMC/SMC are the promising targets!

2-1. Young Type Ib SNR 1E0102-72.3 in SMC
Band 3 with ACA@Cycle1

Band 3

SNR 1E0102-72.3(age: ~1000 yr)➔ known as a
cousin of CasA

Band 9 with ACA@Cycle1

SN 1987A

SNR 1E0102.72.3
is too extended!
40 arcsec

2-2. Young Type Ia SNRs in LMC
24 μm

Hα

X-ray
0509-67.5(400 yr)0519-69.0(600 yr)

Borkowski+2006

shock-heated interstellar
dust ➜ Mdust < 3x10-3 Msunyoung (~500 yr) SNe Ia in LMC
seem too extended (radius~15”)

3-1. Cycle2: SNe Ia as sources of Fe grains○ Missing-iron problem
more than 99% of interstellar Fe atoms
must be locked in dust grains
what grain species tie up iron?
- astronomical silicate (Mg1.1Fe0.9SiO2)➜ no clear evidence for Fe-rich silicates- Fe/FeS grains? Or any other forms?

Sakurai (1993)○ Origin of Fe-bearing grains ➜ SNe Ia
SNe Ia produce more iron (~0.7 M sun) than CCSNe (~0.07 M sun)➜ no evidence for massive dust in the ejecta of Type Ia SNeupper limit of dust mass: M dust < ~10-3 Msun (Gomez+2012)
from Herschel FIR observations of Kepler and Tycho SNRs

Can SNe Ia synthesize Fe grains in the ejecta or not?

3-2. Where is the companion star of SNR 0509?
optical image of SNR 0509-67.5 in LMC・ explosion channel of SNe Ia- single degenerate
WD + MS (or Giant)➜ companion star left
- double degenerate
WD + WD➜ no companion star left
no companion star in central
region of SNR 0509-67.5➔ double degenerate?

Schaefer & Pagnotta+12

However …
there is diffuse emission inthe central region- background galaxy?
- associated with the SNR?

3-3. Where is the companion star of SNR 0509?
optical image of SNR 0509-67.5 in LMC

Radius of the central circle :1.5” = 1.1x1018 cm @ 50 kpc
Vexp = 850 km/s @ 410 yrcorresponds to Fe core !

Supposition
Diffuse emission within thecentral circle may be opticallights scattered by Fe grains
formed in the ejecta

Schaefer & Pagnotta+12

3-4. Dust formation in SNe Ia○ if my supposition is correct …
the optical depth for scattering must be high enough (τ_ sca ~ 1)

τ_sca ~ 1.0 (κ_sca / 1.86x104 cm2/g) (Mdust / 0.1 Msun)- κ_sca = 1.86x104 cm2/g at λ=0.65 µm for a = 0.1 µm- κ_sca = 1.70x103 cm2/g at λ=0.65 µm for a = 1.0 µm## κ_sca is too low for a < 0.01 µm➜ relatively large (>~0.1 µm) radius of Fe grains
dust mass as high as ~0.1 M sun○ Dust formation calculations
Fe grains can efficiently condense at
the inner region of Vexp < ~2000 km/s
- dust radius: < 0.01 µm- dust mass: ~0.05 Msun
➜ Fe grains form in dense clumps?

3-5. Expected SEDs of Fe grain emission
Flux density from Fe grains
with Mdust = 0.1 Msun
Tdust = 30 K
For a = 0.1 µm,
0.18 mJy in Band 7
0.07 mJy in Band 6

For a = 1.0 µm,2.5 mJy in Band 7
1.4 mJy in Band 6
5 sigma detection in 6 hours

If the source is detected, this is the first detectionof the formation of massive dust grains in SNe Ia !
➜ great step to solve the missing-iron problem

3-6. Origin of the central diffuse emission

there are many red backgroundgalaxies around SNR 0509-67.5

4-1. Towards ALMA Cycle3○ Probing dust grains in luminous blue variables (LBVs)- How much dust grains can be formed in LBV winds?
➜ Massive stars can enrich the interstellar medium throughthe formation of dust grains in stellar winds- Dust formation in stellar winds of LBVs is challenging from aview of dust formation theory➜ good laboratory for understanding dust formation process
in astrophysical environments- The presence of circumstellar dust is useful for giving insight
into mass-loss mechanism and evolution of massive stars➜ LBVs as progenitors of Type IIn SNe➜ casting a problem on stellar evolution theory- Optically thick dust winds obscure the central stars and SNe➜ Affecting the progenitor mass estimate and the observed
rate (frequency) of CCSNe

4-2. Proposals accepted in Cycle0○ Number of proposals in Category 5: 8 (out of 112)
(1) R scl (carbon AGB), Maercker, M., et al.
(2) SN 1987A (SNR), Nozawa, T., et al.
(3) Red Rectangle (PPN), Bujarrabal, T., et al.
(4) IRC+10216 (carbon AGB), Cernichao, J., et al.
(5) SN 1987A (SNR), Indebetow, R., et al.
(6) IRC+10216 (carbon AGB), Decin, L., et al.
(7) Eta Carina (LBV), Abraham, Z., et al.
(8) Boomerang Nebula (PPN), Sahai, R., et al.

Candidates of dust-obscured LBVs
- Eta Carina- AFGL 2298 (IRAS18576+0341)(Ueta+2001)- AG Car (Voors+2000)
Buemi+2010

4-3. Proposals accepted in Cycle1○ Number of proposals in Category 5: 21 (out of 196)
(1) SN 1987A (SNR), Indebetow, R.
(2) Red Rectangle (PPN), Bujarrabal, T., et al.
(3) R Sculotoris (carbon RG), Maercker, M., et al.
(4) Helix nebula (PN), Huggins, P., et al.
(5) IRC+10216 (carbon AGB), Cernichao, J., et al.
(6) NGC 6302 (PN), Hirano, N., et al.
(7) IRC+10216 (carbon AGB), Decin, L., et al.
(8) Betelgeuse (RSG), Kervella, P., et al.
(9) VVV-WIT-01 (variable), Minniti, D., et al.
(10) Boomerang Nebula (PPN), Sahai, et al.
(11) IRAS 16432-3814 (bipolar nebula), Sahai, R., et al.
(12) WISE J180956.27-330500.2 (variable), Yamamura, I., et al.
(13) Crab nebula (SNR), Karagaltsev, O., et al.
(14) others: CCSNe (1), NSs (1), GRB (1), AGB star (1), M-dwarfs (1),low-mass stars (1), massive stars (1)(15) unknown (1), AFGL 4176?