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Brian Metzger Princeton University. In collaboration with. Short-Duration Gamma-Ray Burst Central Engines. Eliot Quataert (Berkeley) Todd Thompson (Ohio State) Tony Piro (Berkeley) Niccolo Bucciantini (Nordita) Almudena Arcones (MPIK) - PowerPoint PPT Presentation
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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
BATSE GRBs
Nakar 07
Gamma-Ray Bursts: Long & Short Duration
BATSE GRBs
• High Redshift, zavg ~ 2
• Large Energies (Eiso~1052-54 ergs)
• Star-Forming Host Galaxies
• Type Ic Broad-Line Supernovae
Long
Nakar 07
Gamma-Ray Bursts: Long & Short Duration
BATSE GRBs
• High Redshift, zavg ~ 2
• Large Energies (Eiso~1052-54 ergs)
• Star-Forming Host Galaxies
• Type Ic Broad-Line Supernovae
Long
Nakar 07
Gamma-Ray Bursts: Long & Short Duration
Short
Nakar 07
Merging Compact Objects (NS-NS or BH-NS) Paczynski 1986; Goodman 1986; Eichler+1989; Narayan+ 1992, …
• Target for Advanced LIGO
• Disk left behind w/ mass ~ 10-3 - 0.1 M & size ~ 10-100 km
• cooling via neutrinos: ( >>1, ~ 1 )
€
˙ M ~ 10−2 −10M• s-1
Sh
iba
ta &
Ta
nig
uc
hi 2
00
6
t = 0.7 ms
t = 3 ms
Inspiral “Chirp” Gravitational Waves
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 > 15 ! (Fender et al. 2004)
Similar Systems - Distinct OriginsNS-NS / BH-NS NS-NS / BH-NS
MergersMergers
Accretion-Accretion-Induced Induced CollapseCollapse
BH
NS
M ~ 0.01-0.1 MM ~ 0.01-0.1 M
R ~ 100 km
consistent with short GRB durations
KECK Bloom+06
GRB050509b
GRB050724
Berger+05
HUBBLE Fox+05
GRB050709
z = 0.225 SFR < 0.1 M yr-
1
z = 0.16 SFR = 0.2 M yr-1
z = 0.258 SFR < 0.03 M yr-1
Berger +05
Blo
om
+ 06
Short GRB Host Galaxies
KECK Bloom+06
GRB050509b
GRB050724
Berger+05
HUBBLE Fox+05
GRB050709
z = 0.225 SFR < 0.1 M yr-
1
z = 0.16 SFR = 0.2 M yr-1
z = 0.258 SFR < 0.03 M yr-1
Berger +05
Blo
om
+06
Short GRB Host Galaxies
GRB050724
No Supernova!
• Lower redshift* (z ~ 0.1-1)
• Eiso~ 1049-51 ergs*
• Older Progenitor Population (Consistent
with being drawn from field galaxies; Berger 09)
Short GRBs with Extended X-Ray Emission
BATSE Examples (Norris & Bonnell 2006)
GRB080503SEE/SGRB ~ 30
Pe
rley e
t al. 2
00
8
GRB050709~25% of Swift Bursts (2 classes?) Similarity To GRB Ongoing Engine ActivityEEE/EGRB ~ 1-30 !
Evolution of the Remnant DiskLo
cal D
isk
Mas
s
r2 (
M)
Metzger, Piro, Quataert 2008, 2009 (see also Beloborodov 2009; Lee et al. 2009)
1-D Time-Dependent Models ( viscosity; realistic -cooling)
€
J = (GM•R)1/ 2 MD
Late-Time Outflows
-Particle Formation
• Thick Disks Marginally Bound (Narayan & Yi 94; Blandford & Begelman 99)
}At t ~ 0.1-1 seconds: R ~ 500 km, M ~ 0.3 MAt t ~ 0.1-1 seconds: R ~ 500 km, M ~ 0.3 M initialinitial, T ~ 1 MeV, T ~ 1 MeV
EEBINDBIND ~ GM ~ GMBHBHmmnn/2R ~ 3 MeV nucleon/2R ~ 3 MeV nucleon-1-1
EENUCNUC ~ 7 MeV nucleon ~ 7 MeV nucleon-1-1
~20-40% of the Initial Disk is Ejected Back into Space!~20-40% of the Initial Disk is Ejected Back into Space!
BH
Powerful Winds
Blow Apart Disk
Metzger et al. 2008, 2009
???
Tidal Tails in NS-NS/NS-BH Mergers Lee
& R
amirez-R
uiz 07
Tail(s) with ~10% prompt disk mass
Late-Time Fall-Back Accretion
Rosswog 07
€
dMdt = dM
dE( ) dEdt( ) ∝ t−5 / 3
(Rosswog 07; Faber+06; Lee+09)
€
t fall−back = torb ∝ a3 / 2 ∝ E−3 / 2
+
a
r - Process Heating (not included in present simulations!)
Er ~ 1-3 MeV nucleon-1 released over theat ~ 1 second
Neutrons
Pro
ton
s
Decompressing NS Matter A ~ 100 Nuclei + Free Neutrons (Lattimer+77; Meyer 89):
+
a
r-Process Network Calculations
Metzger, Arcones, Quataert, Martinez-Pinedo 2009
Binding Energy of Merger Ejecta
Total r-Process Heating Along Fall-Back Orbits
Orbital Period
+
a
theat > 1 s theat < 1 s
+
a
torb ~ 1 s
+
a
theat > 1 s theat < 1 s
+
a
torb ~ 1 s
No Late Fall-Back
+
a
theat > 1 s theat < 1 s
+
a
torb ~ 1 s
No Late Fall-Back“Gap”
Metzger, Arcones, Quataert, Martinez-Pinedo 2009
The Effects of r-Process Heating on Fall-back Accretion
Either: Complete Suppression of Fall-Back after t ~ 1 sec
OR “Gap” of t ~ seconds opened
???
Magnetar Spin-Down
Accretion-Induced Collapse
NS-NS Merger with long-lived NS remnant
Following:
NS
Magnetar Spin-DownM
etzger, Q
ua
taert & T
ho
mp
son
08
1015 G
1016 G
3 1015 G
P0= 1 msGRB060614 Overlaid
Accretion-Induced Collapse
NS-NS Merger with long-lived NS remnant
Following:
Internal Shock Emission
~
Po
we
r (1
051 e
rgs
s-1)
NS
High Low
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!)