Short-Duration Gamma-Ray Burst Central Engines

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Short-Duration Gamma-Ray Burst Central Engines
Brian Metzger
Princeton University
In collaboration with
Eliot Quataert (Berkeley) Todd Thompson (Ohio
State) Tony Piro (Berkeley) Niccolo Bucciantini
(Nordita) Almudena Arcones (MPIK) Gabriel
Martinez-Pinedo (MPIK)
Chandra / Einstein Fellows Symposium Harvard
CfA, October 27 2009
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Gamma-Ray Bursts Long Short Duration
BATSE GRBs
Nakar 07
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Gamma-Ray Bursts Long Short Duration
BATSE GRBs
Long

• High Redshift, zavg 2
• Large Energies (Eiso1052-54 ergs)
• Star-Forming Host Galaxies
• Type Ic Broad-Line Supernovae

Nakar 07
4
Gamma-Ray Bursts Long Short Duration
BATSE GRBs
Long

• High Redshift, zavg 2
• Large Energies (Eiso1052-54 ergs)
• Star-Forming Host Galaxies
• Type Ic Broad-Line Supernovae

Nakar 07
Nakar 07
Short
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Merging Compact Objects (NS-NS or BH-NS)
Paczynski 1986 Goodman 1986 Eichler1989
Narayan 1992,
t 0.7 ms
Inspiral Chirp Gravitational Waves
t 3 ms
Shibata Taniguchi 2006

• Target for Advanced LIGO
• Disk left behind w/ mass 10-3 - 0.1 M? size
  10-100 km
• ? cooling via
  neutrinos (?? gtgt1, ?? 1 )

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Accretion-Induced Collapse (AIC)

• Binary Accretion or WD-WD Merger
• Failed Type Ia SN
• Collapse of rapidly-rotating WD ? Disk around
  PNS Mdisk 10-2 - 0.3 M?

Circinus X-1 (Chandra)
Neutron Star Circinus X-1 ? gt 15 ! (Fender et
al. 2004)
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Similar Systems - Distinct Origins
NS-NS / BH-NS Mergers
BH
M 0.01-0.1 M? R 100 km
Accretion-Induced Collapse
NS
consistent with short GRB durations
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GRB050509b
Short GRB Host Galaxies
GRB050709
z 0.16 SFR 0.2 M? yr-1
Bloom 06
z 0.225 SFR lt 0.1 M? yr-1
KECK Bloom06
HUBBLE Fox05
GRB050724
Berger 05
z 0.258 SFR lt 0.03 M? yr-1
Berger05
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GRB050509b
Short GRB Host Galaxies
GRB050709
z 0.16 SFR 0.2 M? yr-1
Bloom 06
No Supernova!
z 0.225 SFR lt 0.1 M? yr-1
KECK Bloom06
HUBBLE Fox05

• Lower redshift (z 0.1-1)
• Eiso 1049-51 ergs
• Older Progenitor Population (Consistent with
  being drawn from field galaxies Berger 09)

GRB050724
Berger 05
GRB050724
z 0.258 SFR lt 0.03 M? yr-1
Berger05
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Short GRBs with Extended X-Ray Emission
25 of Swift Bursts (2 classes?) Similarity
To GRB ? Ongoing Engine Activity EEE/EGRB 1-30
!
GRB050709
GRB080503
SEE/SGRB 30
Perley et al. 2008
BATSE Examples (Norris Bonnell 2006)
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Evolution of the Remnant Disk
Metzger, Piro, Quataert 2008, 2009 (see also
Beloborodov 2009 Lee et al. 2009)
Local Disk Mass ??r2 (M?)
1-D Time-Dependent Models (?
viscosity realistic ?-cooling)
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Late-Time Outflows
Metzger et al. 2008, 2009
At t 0.1-1 seconds R 500 km, M 0.3
Minitial, T 1 MeV

• ?-Particle Formation
• Thick Disks Marginally Bound
• (Narayan Yi 94 Blandford Begelman 99)

EBIND GMBHmn/2R 3 MeV nucleon-1
Powerful Winds Blow Apart Disk
?
?ENUC 7 MeV nucleon-1
BH
20-40 of the Initial Disk is Ejected Back into
Space!
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???
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Tidal Tails in NS-NS/NS-BH Mergers
Lee Ramirez-Ruiz 07
Tail(s) with 10 prompt disk mass
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Late-Time Fall-Back Accretion

(Rosswog 07 Faber06 Lee09)
a
Rosswog 07
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r - Process Heating (not included in present
simulations!)
Decompressing NS Matter ? A 100 Nuclei Free
Neutrons (Lattimer77 Meyer 89)
Protons
Neutrons
?Er 1-3 MeV nucleon-1 released over ?theat 1
second
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r-Process Network Calculations

Metzger, Arcones, Quataert, Martinez-Pinedo 2009
a
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Total r-Process Heating Along Fall-Back Orbits
Orbital Period
Binding Energy of Merger Ejecta
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theat gt 1 s
theat lt 1 s


a
a
torb 1 s


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theat gt 1 s
theat lt 1 s


a
a
torb 1 s


No Late Fall-Back
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theat gt 1 s
theat lt 1 s


a
a
torb 1 s


Gap
No Late Fall-Back
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The Effects of r-Process Heating on Fall-back
Accretion
Metzger, Arcones, Quataert, Martinez-Pinedo 2009
Either Complete Suppression of Fall-Back after t
1 sec OR Gap of ?t seconds opened
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???
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Magnetar Spin-Down
?
Following

• Accretion-Induced Collapse
• NS-NS Merger with long-lived NS remnant

NS
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Magnetar Spin-Down
?
Following

• Accretion-Induced Collapse
• NS-NS Merger with long-lived NS remnant

NS
High ?
Low ?
Internal Shock Emission
Power (1051 ergs s-1)
P0 1 ms
1016 G
GRB060614 Overlaid
3 1015 G
Metzger, Quataert Thompson 08
? ?
1015 G
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Conclusions

• Swift Revolution Afterglows and Host Galaxies
• ? long and short GRBs have distinct progenitors
• NS-NS/NS-BH Remains Promising Model
• ? consistent w/ host galaxies, durations,
  energetics
• accretion disk spreads, explodes at t 1 second.
• ? 100 second X-ray Emission Major Problem
• Oft-Discussed Explanation Fall-Back Accretion
• r-process heating must be taken into account
• ? either natural explanation or makes matters
  worse
• AIC Promising Alternative Model (NS Remains!)

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