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Dark Cosmology Centre, Niels Bohr Institute
The role of core collapse supernovae in the context of dust production in the early universe
Mikkel Juhl HobertDark Cosmology Centre, Niels Bohr Institute
Master’s thesis
Supervisor: Darach Watson
3/22/2016Dias 1
Table of Contents
Introduction• Cosmic dust in the early universe• Core collapse supernovae and supernova remnants
My project• Dust emission and dust models• Cold dust in young core collapse supernova remnants in
the Large Magellanic Cloud
Dark Cosmology Centre, Niels Bohr Institute
3/22/2016Dias 2
Dark Cosmology Centre, Niels Bohr Institute
Cosmic dust
Complex structures of one or more elements.
Only about 0.1% of interstellar matter.
Absorbs and scatters light (extinction).
Reemits absorbed light as infrared radiation.
3/22/2016Dias 3
Dust in the early universe
Dark Cosmology Centre, Niels Bohr Institute
3/22/2016Dias 4
One or more processes must produce large amounts of dust, fast and efficiently.
Dark Cosmology Centre, Niels Bohr Institute
• Death of high mass stars.• Different elements burn in
the star until the core reaches iron.
• Nuclear fusion in the core stops. The star starts to collapse.
• Inner core is compressed into neutrons and neutrinos.
• Outer material bounces on the degenerated core creating a shock.
• Shock initially halts but is revived by neutrino heating.
• Outer material is blasted away leaving a stellar remnant behind.
Core collapse supernovae
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Supernova remnants
• Free expansion phaseLasts for
• Adiabatic phaseLasts for .
• Radiative phaseLasts for .
Dark Cosmology Centre, Niels Bohr Institute
3/22/2016Dias 6
Dark Cosmology Centre, Niels Bohr Institute
Dust emission
Emits thermally, not as a black body
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𝜅𝜈
❑+𝛽
Emits thermally as a gray body
(Rayleigh-Jeans regime)
Dark Cosmology Centre, Niels Bohr Institute
Dust models
Astronomical silicates (AS)(minerals rich in Mg, Si and O) Amorphous carbon(e.g. coal and soot, rich in C).i. ACAR sampleii. BE sample
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Dark Cosmology Centre, Niels Bohr Institute
Observing cold dust
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Spitzer Space Telescope Herschel Space Observatory
Mid infrared(MIPS)
Far infrared and submillimeter(PACS and SPIRE)
Dark Cosmology Centre, Niels Bohr Institute
Young core collapse supernova remnants in the Large Magellanic Cloud
3/22/2016Dias 10
Large Magellanic Cloud• Small and well-known
distance, • Face-on geometry• Rich in gas and dust• Rapid star formation• Many supernovae and
supernova remnants
Sample criteria• Young core collapse
supernova remnants• Must be in regions with little
contamination• Must be distinguishable from
the background
Cold dust in the supernova remnants
Dark Cosmology Centre, Niels Bohr Institute
3/22/2016Dias 11
Subtracting the background with an
annulus
Subtracting the background with a
median filter
Aperture photometry
Uniform background Varying background
Dark Cosmology Centre, Niels Bohr Institute
Cold dust in the supernova remnants
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24𝜇m70𝜇m100𝜇m160𝜇m
250𝜇m350𝜇m500𝜇m
Dark Cosmology Centre, Niels Bohr Institute
Cold dust in the supernova remnants
3/22/2016Dias 13
N49
Dark Cosmology Centre, Niels Bohr Institute
Cold dust in the supernova remnants
3/22/2016Dias 14
24𝜇m
70𝜇m100𝜇m160𝜇m
250𝜇m350𝜇m500𝜇m
70𝜇m100𝜇m160𝜇m
250𝜇m350𝜇m500𝜇m
24𝜇m
Dark Cosmology Centre, Niels Bohr Institute
Cold dust in the supernova remnants
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N132D
Dark Cosmology Centre, Niels Bohr Institute
Cold dust in the supernova remnants
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SNR AS () (K)
ACAR () (K)
BE () (K)
SN1987AN11LN23
N132DN49
N63A
Dark Cosmology Centre, Niels Bohr Institute
Dust from swept-up interstellar matter
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(neutral) (ionized) (molecular)
Dark Cosmology Centre, Niels Bohr Institute
Dust from swept-up interstellar matter
SNR() () () ()
D2G*() ()
SN1987A ... ... ... 1 4.15N11L 2.64 0.81 ... 3.45 4.17 1.0N23 1.38 0.66 ... 2.04 4.44 0.2
N132D 1.34 0.87 0.21 2.63 8.26 4.5N49 3.14 1.96 0.13 5.36 6.25 6.2
N63A 0.28 2.1 ... 2.38 9.62 2.0
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*Temim et al. (2015)
Dark Cosmology Centre, Niels Bohr Institute
Summary
• Each target must produce, on average, of dust (Dwek et al., 2007).
• Low amounts of observed dust in N11L and N23.• High amounts of observed dust in SN1987A and N63A.• Dust in N132D and N49 is probably swept up.
• Total dust mass strongly depends oni. The specific dust model.ii. The accuracy of the background subtraction.
• Still uncertainty surrounding core collapse supernovae as key contributors of dust.
• They are likely not the only significant sources of dust.
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