Kyoto, Nov 14 2013

The longterm evolution ofneutron star merger ejecta

Stephan Rosswog
in collaboration with:
Almudena Arcones (Darmstadt)
Oleg Korobkin (Stockholm)
Thursday, November 14, 2013

Doron Grossman (Jerusalem)
Tsvi Piran (Jerusalem)
Friedrich-Karl Thielemann (Basel)Overview
I. Intro/Reviewa) EM signals ⇔ GWsb) Summary: compact binary mergers as producers of “heavy” r-process⇒ “macronovae”

II. Remnant evolutiona) What is new?
b) Inclusion of nuclear heatingc) Effect on dynamics and nucleosynthesisd) Remnant structure

III. EM emissiona) Procedureb) Major results

VI. Summary
Thursday, November 14, 2013

References:a) SR et al., arXiv13007.2939b) Grossman et al., arXiv13007.2943

I. Intro/Review
Direct gravitational wave (GW) detection• LIGO & VIRGO detector upgrade ⇒ access. volume increased by > factor 1000
initial LIGOAdvanced LIGO

Thursday, November 14, 2013

I. Intro/Review
Direct gravitational wave (GW) detection• LIGO & VIRGO detector upgrade ⇒ access. volume increased by > factor 1000
initial LIGOAdvanced LIGO

• “multi-messenger” approach

Thursday, November 14, 2013

I. Intro/Review
Direct gravitational wave (GW) detection• LIGO & VIRGO detector upgrade ⇒ access. volume increased by > factor 1000
initial LIGOAdvanced LIGO

• “multi-messenger” approach
Gravitational waves‣ masses‣ spins‣ nuclear EOS‣ ...

Thursday, November 14, 2013⇒ physics of binary system

I. Intro/Review
Direct gravitational wave (GW) detection• LIGO & VIRGO detector upgrade ⇒ access. volume increased by > factor 1000
initial LIGOAdvanced LIGO

• “multi-messenger” approach
Gravitational waves‣ masses‣ spins‣ nuclear EOS‣ ...

⇒ physics of binary system

Electromagnetic signals‣ redshift‣ type of galaxy⇒ astronomical environment‣ ambient medium‣ ...
Thursday, November 14, 2013

I. Intro/Review
Direct gravitational wave (GW) detection• LIGO & VIRGO detector upgrade ⇒ access. volume increased by > factor 1000
initial LIGOAdvanced LIGO

• “multi-messenger” approach
Gravitational waves‣ masses‣ spins‣ nuclear EOS‣ ...

Which additional signatures are produced⇒ physics of binary system
by compact object encounters?

Electromagnetic signals‣ redshift‣ type of galaxy⇒ astronomical environment‣ ambient medium‣ ...

⇒ related to ejected mass

Thursday, November 14, 2013

Rapid neutron capture nucleosynthesis (“r-process”)• Big Bang: elements up to 7Li/7Be• hydrostatic stellar burning: up to “iron-group”• beyond “iron group”: mainly neutron capture processes“double peaks”

Xe

Ba

r s

“Big Bang” “stellar burning”
Thursday, November 14, 2013

Pt

Pb

r s

“neutron captures”

Rapid neutron capture nucleosynthesis (“r-process”)• Big Bang: elements up to 7Li/7Be• hydrostatic stellar burning: up to “iron-group”• beyond “iron group”: mainly neutron capture processes⇒ essentially
two neutron capture
processes in nature:• rapid n-capture(“r-process”)“double peaks”

Xe

Ba

r s

“Big Bang” “stellar burning”
Thursday, November 14, 2013

Pt

Pb

r s

“neutron captures”• slow n-capture(“s-process”)

Rapid neutron capture nucleosynthesis (“r-process”)• Big Bang: elements up to 7Li/7Be• hydrostatic stellar burning: up to “iron-group”• beyond “iron group”: mainly neutron capture processes⇒ essentially
two neutron capture
processes in nature:

What is/are the astrophysical sources of• rapid n-capture
the r-process?
(“r-process”)“double peaks”

Xe

Ba

r s

“Big Bang” “stellar burning”
Thursday, November 14, 2013

Pt

Pb

r s

“neutron captures”• slow n-capture(“s-process”)

Neutron star mergers as r-process source?
• suggestion:

Lattimer &Schramm 1974

Thursday, November 14, 2013

Neutron star mergers as r-process source?
• suggestion:

Lattimer &Schramm 1974

Thursday, November 14, 2013

Neutron star mergers as r-process source?
• suggestion:

Lattimer &Schramm 1974

• discussion:

Eichler et al. 1989:“Nucleosynthesis, neutrino
bursts and gamma-rays fromcoalescing neutron stars”

Thursday, November 14, 2013

Neutron star mergers as r-process source?
• suggestion:

Lattimer &Schramm 1974

• discussion:

Eichler et al. 1989:“Nucleosynthesis, neutrino
bursts and gamma-rays fromcoalescing neutron stars”• calculation:- SR et al. 1999:“Mass ejection in neutron starmergers”- Freiburghaus, SR, Thielemann 1999:“R-Process in neutron star mergers”

Thursday, November 14, 2013

Neutron star mergers as r-process source?
• suggestion:

Lattimer &Schramm 1974

• discussion:

Eichler et al. 1989:“Nucleosynthesis, neutrino
bursts and gamma-rays fromcoalescing neutron stars”• calculation:- SR et al. 1999:“Mass ejection in neutron starmergers”- Freiburghaus, SR, Thielemann 1999:“R-Process in neutron star mergers”• further refined in a number of recent studies, e.g.
- Goriely et al. 2011
- Roberts et al. 2011
- Korobkin et al. 2012
- Bauswein et al. 2013
- ...

Thursday, November 14, 2013

“Macro-”/”Kilonovae”

Thursday, November 14, 2013

“Macro-”/”Kilonovae”• much recent work

- Kulkarni 2005
- SR 2005- Metzger et al. 2010
- Roberts et al. 2011
- Goriely et al. 2011
- Metzger & Berger 2012
- Piran et al. 2013
- SR et al. 2013a- ...

Thursday, November 14, 2013

“Macro-”/”Kilonovae”• much recent work

- Kulkarni 2005
- SR 2005- Metzger et al. 2010
- Roberts et al. 2011
- Goriely et al. 2011
- Metzger & Berger 2012
- Piran et al. 2013
- SR et al. 2013a- ...

Thursday, November 14, 2013

- Kasen et al. 2013
- Barnes & Kasen 2013
- SR et al. 2013,- Grossman et al. 2013
- Tanaka et al. 2013
- Tanaka & Hotokezaka 2013
- Hotokezaka et al. 2013

⇒ “VERY large opacities”⇒ IR, not opt./UV

Channels to eject mass

Thursday, November 14, 2013

Channels to eject mass

ultra-relativistic
outflow, " > 100

interaction region
jet-wind, " ~ few (?)

neutrino-driven winds!v" ! 0.1c
dynamic ejecta!v" ! 0.1c
Thursday, November 14, 2013

Channels to eject mass

ultra-relativistic
outflow, " > 100

interaction region
jet-wind, " ~ few (?)

neutrino-driven winds!v" ! 0.1c
dynamic ejecta!v" ! 0.1c
Thursday, November 14, 2013

Channels to eject mass

ultra-relativistic
outflow, " > 100

interaction region
jet-wind, " ~ few (?)

neutrino-driven winds!v" ! 0.1c
dynamic ejecta!v" ! 0.1c
Thursday, November 14, 2013

Channels to eject mass

ultra-relativistic
outflow, " > 100

interaction region
jet-wind, " ~ few (?)

neutrino-driven winds!v" ! 0.1c
+ late-time disk-disintegration

dynamic ejecta!v" ! 0.1c
Thursday, November 14, 2013

a) “dynamic ejecta”(grav. torques, hydrodyn. interaction;
movie from Rosswog et al. 2013)

Thursday, November 14, 2013

a) “dynamic ejecta”(grav. torques, hydrodyn. interaction;
movie from Rosswog et al. 2013)

Thursday, November 14, 2013

typical merger case:
1.3 & 1.4 Msol, no spina) “dynamic ejecta”(grav. torques, hydrodyn. interaction;
movie from Rosswog et al. 2013)⇒ mej ∼ 0.01 Msol

Thursday, November 14, 2013

typical merger case:
1.3 & 1.4 Msol, no spina) “dynamic ejecta”(grav. torques, hydrodyn. interaction;
movie from Rosswog et al. 2013)⇒ mej ∼ 0.01 Msolb) “neutrino-driven wind”(neutrinos deposit energy via
νe + p ➝ n + e+ andνe + n ➝ p + e- ;movie from Dessart et al. 2009,see also talks by A. Perego
R. Surman

Thursday, November 14, 2013)

typical merger case:
1.3 & 1.4 Msol, no spina) “dynamic ejecta”(grav. torques, hydrodyn. interaction;
movie from Rosswog et al. 2013)⇒ mej ∼ 0.01 Msolb) “neutrino-driven wind”(neutrinos deposit energy via
νe + p ➝ n + e+ andνe + n ➝ p + e- ;movie from Dessart et al. 2009,see also talks by A. Perego
R. Surman

Thursday, November 14, 2013)

typical merger case:
1.3 & 1.4 Msol, no spina) “dynamic ejecta”(grav. torques, hydrodyn. interaction;
movie from Rosswog et al. 2013)⇒ mej ∼ 0.01 Msolb) “neutrino-driven wind”(neutrinos deposit energy via
νe + p ➝ n + e+ andνe + n ➝ p + e- ;movie from Dessart et al. 2009,see also talks by A. Perego
R. Surman)⇒ mej ∼ 10-4 Msol
Thursday, November 14, 2013

typical merger case:
1.3 & 1.4 Msol, no spinc) “accretion disk dissolves”• disks initially very hot, several MeV,

matter dis-integrate into free nucleons• as disk spreads, neutrino-cooling

becomes inefficient for T < 1 MeV• nucleons re-combine into α-particles, thishappens at radii where Enuc/bar. ∼ Egrav/bar.

Thursday, November 14, 2013

(Beloborodov 2008)

c) “accretion disk dissolves”• disks initially very hot, several MeV,

matter dis-integrate into free nucleons• as disk spreads, neutrino-cooling

becomes inefficient for T < 1 MeV• nucleons re-combine into α-particles, this(Beloborodov 2008)

happens at radii where Enuc/bar. ∼ Egrav/bar.

⇒ “evaporation” of ∼ 0.1 Mdisk(t0)(Beloborodov 2008, Metzger et al. 2008, Lee et al. 2009; Fernandez & Metzger 2013)

Thursday, November 14, 2013

c) “accretion disk dissolves”• disks initially very hot, several MeV,

matter dis-integrate into free nucleons• as disk spreads, neutrino-cooling

becomes inefficient for T < 1 MeV• nucleons re-combine into α-particles, this(Beloborodov 2008)

happens at radii where Enuc/bar. ∼ Egrav/bar.

⇒ “evaporation” of ∼ 0.1 Mdisk(t0)(Beloborodov 2008, Metzger et al. 2008, Lee et al. 2009; Fernandez & Metzger 2013)⇒ mej ∼ 0.02 Msol
Thursday, November 14, 2013

Qualitative differences/tendencies“dynamic ejecta”

Thursday, November 14, 2013

Qualitative differences/tendencies“dynamic ejecta”
2 sources:

Thursday, November 14, 2013

Qualitative differences/tendencies“dynamic ejecta”
2 sources: “tidal component”

Thursday, November 14, 2013

Qualitative differences/tendencies“dynamic ejecta”
2 sources: “tidal component”“interaction
component”

Thursday, November 14, 2013

Qualitative differences/tendencies“dynamic ejecta”
2 sources: “tidal component”“interaction
component”• “ejected fast”, τ∼ 1 ms

⇒ too cold/too fast for substantial Ye change via EC-/PC capture⇒ bulk of matter at original, cold β-equilibrium Ye

Thursday, November 14, 2013

Qualitative differences/tendencies“dynamic ejecta”
2 sources: “tidal component”“interaction
component”• “ejected fast”, τ∼ 1 ms

⇒ too cold/too fast for substantial Ye change via EC-/PC capture⇒ bulk of matter at original, cold β-equilibrium Ye(Rosswog et al. 2013)

Thursday, November 14, 2013

(Korobkin et al. 2013)

Qualitative differences/tendencies“dynamic ejecta”
2 sources: “tidal component”“interaction
component”• “ejected fast”, τ∼ 1 ms

⇒ too cold/too fast for substantial Ye change via EC-/PC capture⇒ bulk of matter at original, cold β-equilibrium Ye(Rosswog et al. 2013)(Korobkin et al. 2013)⇒ large neutron-to-seed ratio⇒ very heavy nuclei up to/beyond platinum peak (A ∼ 195)⇒ very large opacities (Kasen et al. 2013)⇒ late, dim macronova peak, IR
Thursday, November 14, 2013

“ν-wind and disk-dissolution”
2 / (Ω α) ∼ 100 ms“ejected
substantiallyslower”:
τ
∼
τ
∼
(r/H)
ν-captureaccretion•

Thursday, November 14, 2013

“ν-wind and disk-dissolution”
2 / (Ω α) ∼ 100 ms“ejected
substantiallyslower”:
τ
∼
τ
∼
(r/H)
ν-captureaccretion•⇒ hot (∼ 1 MeV) environment, can change
via EC-/PC capture for disk-disintegration(e.g. Fernandez & Metzger 2013)

Thursday, November 14, 2013

➞ Ye ∼ 0.2

“ν-wind and disk-dissolution”
2 / (Ω α) ∼ 100 ms“ejected
substantiallyslower”:
τ
∼
τ
∼
(r/H)
ν-captureaccretion•⇒ hot (∼ 1 MeV) environment, can change
via EC-/PC capture for disk-disintegration➞ Ye ∼ 0.2(e.g. Fernandez & Metzger 2013)orsequence of ν/ν capture for ν-wind,Ye set by ratio of ν-ν luminosities (Qian+ 1996)

Thursday, November 14, 2013

➞ Ye ∼ 0.3 - 0.4

“ν-wind and disk-dissolution”
2 / (Ω α) ∼ 100 ms“ejected
substantiallyslower”:
τ
∼
τ
∼
(r/H)
ν-captureaccretion•⇒ hot (∼ 1 MeV) environment, can change
via EC-/PC capture for disk-disintegration➞ Ye ∼ 0.2(e.g. Fernandez & Metzger 2013)orsequence of ν/ν capture for ν-wind,Ye set by ratio of ν-ν luminosities (Qian+ 1996)➞ Ye ∼ 0.3 - 0.4⇒ less heavy nuclei⇒ lower opacities⇒ earlier el.mag. peak
⇒ for quantitative answers multi-D neutrino-hydro required

Thursday, November 14, 2013

“ν-wind and disk-dissolution”
2 / (Ω α) ∼ 100 ms“ejected
substantiallyslower”:
τ
∼
τ
∼
(r/H)
ν-captureaccretion•⇒ hot (∼ 1 MeV) environment, can change
via EC-/PC capture for disk-disintegration➞ Ye ∼ 0.2(e.g. Fernandez & Metzger 2013)orsequence of ν/ν capture for ν-wind,Ye set by ratio of ν-ν luminosities (Qian+ 1996)➞ Ye ∼ 0.3 - 0.4⇒ less heavy nuclei⇒ lower opacities⇒ earlier el.mag. peak
⇒ for quantitative answers multi-D neutrino-hydro required
all channels have different properties

Thursday, November 14, 2013

“ν-wind and disk-dissolution”
2 / (Ω α) ∼ 100 ms“ejected
substantiallyslower”:
τ
∼
τ
∼
(r/H)
ν-captureaccretion•⇒ hot (∼ 1 MeV) environment, can change
via EC-/PC capture for disk-disintegration➞ Ye ∼ 0.2(e.g. Fernandez & Metzger 2013)orsequence of ν/ν capture for ν-wind,Ye set by ratio of ν-ν luminosities (Qian+ 1996)➞ Ye ∼ 0.3 - 0.4⇒ less heavy nuclei⇒ lower opacities⇒ earlier el.mag. peak
⇒ for quantitative answers multi-D neutrino-hydro required
all channels have different properties
all channels may be important fori) nucleosynthesisii) el.mag. transients
Thursday, November 14, 2013

“ν-wind and disk-dissolution”
2 / (Ω α) ∼ 100 ms“ejected
substantiallyslower”:
τ
∼
τ
∼
(r/H)
ν-captureaccretion•⇒ hot (∼ 1 MeV) environment, can change
via EC-/PC capture for disk-disintegration➞ Ye ∼ 0.2(e.g. Fernandez & Metzger 2013)orsequence of ν/ν capture for ν-wind,Ye set by ratio of ν-ν luminosities (Qian+ 1996)➞ Ye ∼ 0.3 - 0.4⇒ less heavy nuclei⇒ lower opacities⇒ earlier el.mag. peak
⇒ for quantitative answers multi-D neutrino-hydro required
all channels have different properties
all channels may be important fori) nucleosynthesisii) el.mag. transients
Thursday, November 14, 2013⇒

from now on:
dynamic ejecta

Simulation ingredients:• 3D, Lagrangian Hydrodynamics (SPH) & (Newtonian) Gravity• equation of state: density, temperature and composition
dependent nuclear equation of state (Shen et al. 1998)• neutrino emission:- opacity-dependent multi-flavour
leakage scheme;- Ye-change via electron/positron
captures
References:★ SR & Davies, MNRAS 334, 481 (2002)★ SR & Liebendörfer, MNRAS 342, 673 (2003)★ SR & Price, MNRAS 379, 915 (2007))Thursday, November 14, 2013

neutrino optical depths
τν > 104τν ∼ 1τν ≈ 0Dynamical mass ejection
typical merger case:
1.3 & 1.4 Msol, no spin

Thursday, November 14, 2013

visualized:
Ye value at given
optical depthDynamical mass ejection
typical merger case:
1.3 & 1.4 Msol, no spin

total amount: 0.014 Msol
extremely neutron rich: Ye≈ 0.03,
with small crust contaminations
velocityThursday, November 14, 2013v≈ 0.1 cvisualized:
Ye value at given
optical depthDisk formation: Ye and velocity

2 x 1.4 Msol

Thursday, November 14, 2013

“r-process in action” for dynamical ejecta (Korobkin, Rosswog, Arcones, Winteler 2012)

Thursday, November 14, 2013

“r-process in action” for dynamical ejecta (Korobkin, Rosswog, Arcones, Winteler 2012)

Thursday, November 14, 2013

“r-process in action” for dynamical ejecta (Korobkin, Rosswog, Arcones, Winteler 2012)

Thursday, November 14, 2013

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

Thursday, November 14, 2013

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

What’s new?

Thursday, November 14, 2013

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

What’s new?
a) Inclusion of heating from nuclear reactions into 3D hydrodynamics

Thursday, November 14, 2013

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

What’s new?
a) Inclusion of heating from nuclear reactions into 3D hydrodynamicsb) Explore its effect on matter dynamics and nucleosynthesis

Thursday, November 14, 2013

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

What’s new?
a) Inclusion of heating from nuclear reactions into 3D hydrodynamicsb) Explore its effect on matter dynamics and nucleosynthesisc) Remnant structure at the times that are relevant for el.mag. emission:

Thursday, November 14, 2013

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

What’s new?
a) Inclusion of heating from nuclear reactions into 3D hydrodynamicsb) Explore its effect on matter dynamics and nucleosynthesisc) Remnant structure at the times that are relevant for el.mag. emission:∼ days for Macronovae & ∼months for interaction with ambient medium

Thursday, November 14, 2013

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

What’s new?
a) Inclusion of heating from nuclear reactions into 3D hydrodynamicsb) Explore its effect on matter dynamics and nucleosynthesisc) Remnant structure at the times that are relevant for el.mag. emission:∼ days for Macronovae & ∼months for interaction with ambient mediumd) evolution up to 100 years

Thursday, November 14, 2013>>

∼20 ms of most merger simulations

II. Remnant evolution“How are the properties of the ejected matter at the times thatare relevant for electromagnetic emission?”

What’s new?
a) Inclusion of heating from nuclear reactions into 3D hydrodynamicsb) Explore its effect on matter dynamics and nucleosynthesisc) Remnant structure at the times that are relevant for el.mag. emission:∼ days for Macronovae & ∼months for interaction with ambient mediumd) evolution up to 100 years>>∼20 ms of most merger simulationse) radiative signature from 3D remnant geometry

Thursday, November 14, 2013

Time scales
Astrophysics

Thursday, November 14, 2013

Time scales
Astrophysics∼ 100 ms
• τaccretion ∼ (r/H)2 / (Ω α)∼1s• end of neutron captures:∼ days• macronovae:• interaction with ambient medium: ∼ months

Thursday, November 14, 2013

Time scales
Astrophysics∼ 100 ms
• τaccretion ∼ (r/H)2 / (Ω α)∼1s• end of neutron captures:∼ days• macronovae:• interaction with ambient medium: ∼ months
Numerics

Thursday, November 14, 2013

Time scales
Astrophysics∼ 100 ms
• τaccretion ∼ (r/H)2 / (Ω α)∼1s• end of neutron captures:∼ days• macronovae:• interaction with ambient medium: ∼ months
Numerics• time step restriction by Courant-Friedrichs-Lewy condition: Δt < Δx/cs

Thursday, November 14, 2013

Time scales
Astrophysics∼ 100 ms
• τaccretion ∼ (r/H)2 / (Ω α)∼1s• end of neutron captures:∼ days• macronovae:• interaction with ambient medium: ∼ months
Numerics• time step restriction by Courant-Friedrichs-Lewy condition: Δt < Δx/cs
Δt ≈ 10-7 s⇒ merger simulations typicallyrun up to ∼ 20 ms

Thursday, November 14, 2013

Time scales
Astrophysics∼ 100 ms
• τaccretion ∼ (r/H)2 / (Ω α)∼1s• end of neutron captures:∼ days• macronovae:• interaction with ambient medium: ∼ months
Numerics• time step restriction by Courant-Friedrichs-Lewy condition: Δt < Δx/cs
Δt ≈ 10-7 s⇒ merger simulations typicallyrun up to ∼ 20 ms⇒ usually: extrapolation for nucleosynthesis
and macronova calculations

Thursday, November 14, 2013

Time scales
Astrophysics∼ 100 ms
• τaccretion ∼ (r/H)2 / (Ω α)∼1s• end of neutron captures:∼ days• macronovae:• interaction with ambient medium: ∼ months
Numerics• time step restriction by Courant-Friedrichs-Lewy condition: Δt < Δx/cs
Δt ≈ 10-7 s⇒ merger simulations typicallyrun up to ∼ 20 ms⇒ usually: extrapolation for nucleosynthesis
and macronova calculations⇒ our strategy:a) replace dense inner parts by potentialb) follow outflowing matter only
Thursday, November 14, 2013

Implementing heating from radioactive decay into hydrodynamics(figure from Korobkin et al. 2012)

Thursday, November 14, 2013

Implementing heating from radioactive decay into hydrodynamics
heating history for ejecta trajectory
relatively simple:“const. + power law”
⇒ use fit formulae for ėnuc , Z̄, Ā(figure from Korobkin et al. 2012)

Thursday, November 14, 2013

⇒ implement heatingin hydrodynamics

Implementing heating from radioactive decay into hydrodynamics
heating history for ejecta trajectory
relatively simple:“const. + power law”
⇒ use fit formulae for ėnuc , Z̄, Ā(figure from Korobkin et al. 2012)⇒ implement heatingin hydrodynamics“When does matter start to be decelerated substantially?”

Thursday, November 14, 2013

Implementing heating from radioactive decay into hydrodynamics
heating history for ejecta trajectory
relatively simple:“const. + power law”
⇒ use fit formulae for ėnuc , Z̄, Ā(figure from Korobkin et al. 2012)⇒ implement heatingin hydrodynamics“When does matter start to be decelerated substantially?”“swept up mass = ejected mass”

Thursday, November 14, 2013

Implementing heating from radioactive decay into hydrodynamics
heating history for ejecta trajectory
relatively simple:“const. + power law”
⇒ use fit formulae for ėnuc , Z̄, Ā(figure from Korobkin et al. 2012)⇒ implement heatingin hydrodynamics“When does matter start to be decelerated substantially?”“swept up mass = ejected mass”⇒ deceleration radius:
Rdec = 0.5 pc

Thursday, November 14, 2013

�

−1/3

mej
1 cm
10−2 M⊙ namb

�1/3

Implementing heating from radioactive decay into hydrodynamics
heating history for ejecta trajectory
relatively simple:“const. + power law”
⇒ use fit formulae for ėnuc , Z̄, Ā(figure from Korobkin et al. 2012)⇒ implement heatingin hydrodynamics“When does matter start to be decelerated substantially?”“swept up mass = ejected mass”⇒ deceleration radius:
Rdec = 0.5 pc

�

−1/3

mej
1 cm
10−2 M⊙ namb

�1/3

⇒ deceleration time:τdec = 15 yrs
Thursday, November 14, 2013

�

−1/3

mej
1 cm
10−2 M⊙ namb

�1/3 �

0.1 c
vej

�

Implementing heating from radioactive decay into hydrodynamics
heating history for ejecta trajectory
relatively simple:“const. + power law”
⇒ use fit formulae for ėnuc , Z̄, Ā(figure from Korobkin et al. 2012)⇒ implement heatingin hydrodynamics“When does matter start to be decelerated substantially?”“swept up mass = ejected mass”⇒ deceleration radius:
Rdec = 0.5 pc

�

−1/3

mej
1 cm
10−2 M⊙ namb

�1/3

⇒ stop simulations after t = 100 years⇒ deceleration(>> ∼20 mstime:of usual merger simulation)
τdec = 15 yrs
Thursday, November 14, 2013

�

−1/3

mej
1 cm
10−2 M⊙ namb

�1/3 �

0.1 c
vej

�

“How does the heating from radioactive decays impact
on the further evolution of the remnant?”
t= 19ms

t= 1 daywith radioactive heatingt= 100 yrs

without radioactive heating(from SR et al. 2013)
Thursday, November 14, 2013

Effect of radioactive heating on density and temperature evolution

Thursday, November 14, 2013

Effect of radioactive heating on density and temperature evolution
densityThursday, November 14, 2013

temperature

Effect of radioactive heating on density and temperature evolution
densitytemperature⇒ at any time larger than ∼1s:
density lower/temperature higher by > 1 order of magnitudeThursday, November 14, 2013

Effect of radioactive heating on density and temperature evolution
densitytemperature⇒ at any time larger than ∼1s:
density lower/temperature higher by > 1 order of magnitude⇒ Is standard procedure for nucleosynthesis post-processinga) hydrodynamics WITHOUT heatingb) post-process temperature, but not density
justified?
Thursday, November 14, 2013

temperature evolution⇒ differences seem acceptably small

Thursday, November 14, 2013

resulting nuclear abundances

Longterm hydrodynamic evolution: “100 years, but still in shape”

Thursday, November 14, 2013

Longterm hydrodynamic evolution: “100 years, but still in shape”

2 × 1.4M⊙

Thursday, November 14, 2013

Longterm hydrodynamic evolution: “100 years, but still in shape”
after 1 day

2 × 1.4M⊙
5x10-4 pc

Thursday, November 14, 2013

Longterm hydrodynamic evolution: “100 years, but still in shape”
after 1 day

after 1 year

5x10-4 pc

0.15 pc

2 × 1.4M⊙

Thursday, November 14, 2013

Longterm hydrodynamic evolution: “100 years, but still in shape”
after 1 day

after 1 year

after 100 yearsz

2 × 1.4M⊙
5x10-4 pc

Thursday, November 14, 20130.15 pc

15 pc

xLongterm hydrodynamic evolution: “100 years, but still in shape”
after 1 day

after 1 year

after 100 yearsz

2 × 1.4M⊙
5x10-4 pc

1.3 & 1.4M⊙

Thursday, November 14, 20130.15 pc

15 pc

xLongterm hydrodynamic evolution: “100 years, but still in shape”
after 1 day

after 1 year

after 100 yearsz

2 × 1.4M⊙
5x10-4 pc

1.3 & 1.4M⊙

Thursday, November 14, 20130.15 pc

15 pc

xLongterm hydrodynamic evolution: “100 years, but still in shape”
after 1 day

after 1 year

after 100 yearsz

2 × 1.4M⊙
5x10-4 pc

0.15 pc

15 pc

x

1.3 & 1.4M⊙• self-similar solution, after 100 s: better than 1% homologous• remnant does not become spherical in first 100 years• still carries memory of initial mass ratio
Thursday, November 14, 2013

Density evolution:

Thursday, November 14, 2013

Density evolution:from:a) few times nucl. matter density (“neutron star”) ⇒ Shen-EOSb) white dwarf densities⇒ Helmholtz EOS (Timmes 2000)c) ISM-like densities⇒ ideal gas + rad.

Thursday, November 14, 2013

Density evolution:from:a) few times nucl. matter density (“neutron star”) ⇒ Shen-EOSb) white dwarf densities⇒ Helmholtz EOS (Timmes 2000)c) ISM-like densities⇒ ideal gas + rad.

during first century densities drop by ∼40 orders of magnitude(few x 1014 to ∼10-25 g/ccm)
Thursday, November 14, 2013

Extracting the radiative signature from expanding remnant
1.4 & 1.4

1.3 & 1.4

input/assumptions:• opacities: κ= 10 cm2/g(Kasen et al. 2013;
Tanaka & Hotokezaka 2013)• heating rate directly from
1.8 & 1.2

1.8 & 1.2

our network calculations• radiation ≈ BB
“trapped component”
τ > τdiff“diffusion surface”:
τdiff = τdyn“radiating volume”
τdiff < τ < 2/3“Photosphere”:
τdiff = τdyn
“photons from escaping
with energies set by nuclear
reactions; not considered”
τ < τdiffThursday, November 14, 2013

dL
(k) =
dΩ

� τ (r)<ct/ζ(r)τ (r)>2/3,k·n>0

k · n �˙(t)ρ(r)d3 r

Tendencies:i) asymmetric systems
are brighterii) ∼ factor of 2
between “top” and“front” view

“flat” peak at ∼ 3days:
Lp≈ 3 x 1040 erg/s
Teff≈ 2500 K
Thursday, November 14, 2013

Summary• compact binary mergers are likely sources of r-process• they eject (at least) via three different channels:a) dynamic ejectab) ν-driven windsc) “accretion disk dissolutions”⎫⎬ ⇒ different properties⎭• likely all relevant for nucleosynthesis and el.mag. transients• better understanding of “macronovae” required

Thursday, November 14, 2013

Summary• compact binary mergers are likely sources of r-process• they eject (at least) via three different channels:a) dynamic ejecta⎫⇒ different
propertiesb) ν-driven winds
Thank you for ⎬⎭yourattention!
c) “accretion disk dissolutions”• likely all relevant for nucleosynthesis and el.mag. transients• better understanding of “macronovae” required

Thursday, November 14, 2013