Gamma-Ray Burst Central Engines - Princeton University
Gamma-Ray Burst Central Engines - Princeton University
Gamma-Ray Burst Central Engines - Princeton University
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<strong>Gamma</strong>-<strong>Ray</strong> <strong>Burst</strong> <strong>Central</strong> <strong>Engines</strong><br />
Brian Metzger<br />
<strong>Princeton</strong> <strong>University</strong> (NASA Einstein Fellow)<br />
In collaboration with<br />
Eliot Quataert (Berkeley)<br />
Todd Thompson (Ohio State)<br />
Tony Piro (Berkeley)<br />
Niccolo Bucciantini (Nordita)<br />
Almudena Arcones (MPIK)<br />
Gabriel Martinez-Pinedo (MPIK)<br />
Dimitrios Giannios (<strong>Princeton</strong>)<br />
Frank N. Bash Symposium<br />
October 19 2009, UT Austin
• <strong>Gamma</strong>-<strong>Ray</strong> <strong>Burst</strong>s:<br />
Constraints on the <strong>Central</strong> Engine<br />
• Long-Duration<br />
– Black Hole (“Collapsar”)<br />
– “Millisecond Magnetar”<br />
• Short-Duration<br />
– Compact Object Mergers<br />
(BH⇔NS, NS⇔NS)<br />
– Accretion-Induced Collapse<br />
(WD ⇒ NS)<br />
Outline<br />
short<br />
long<br />
BATSE <strong>Burst</strong>s (from Nakar 2007)
“When you’ve seen one GRB….<br />
you’ve seen one GRB?”<br />
BATSE <strong>Burst</strong>s<br />
“Short GRBs with<br />
Extended Emission”<br />
GRB 080503<br />
GRB 050709
Relativistic Outflow (Γ >> 1)<br />
~ 10 7 cm<br />
<strong>Central</strong> Engine<br />
GRB Emission: Still Elusive!<br />
GRB / Flaring<br />
1. What is jet’s composition? (kinetic or magnetic?)<br />
Afterglow<br />
2. Where is dissipation occurring? (photosphere? deceleration radius?)<br />
3. How is radiation generated? (synchrotron, inverse-compton, hadronic?)
• Extreme <strong>Burst</strong>s (e.g. 080916C: E iso = 8.8 x 10 54 ergs )<br />
• Distinct GeV Component<br />
– Delayed wrt MeV photons<br />
– Slow Decay ( ~ t -1.5 )<br />
– Both Long and Short <strong>Burst</strong>s (e.g. GRB 090510)<br />
GBM (8 keV - 40 MeV)<br />
LAT (20MeV - 300 GeV)<br />
– Origin: Prompt? Afterglow? (e.g. Kumar & Barniol Duran 09; Ghirlanda+09)<br />
090510<br />
Ghirlanda et al. 2009<br />
090902B (Fermi Collaboration 09)
Constraints on the <strong>Central</strong> Engine<br />
• Cosmological ➙ Huge Energies (~10 49 -10 52 ergs, collimated)<br />
• Energy / Millisecond Variability ➙ Black Hole or Neutron Star<br />
• <strong>Gamma</strong>-<strong>Ray</strong> Spectrum ➙ Ultra-Relativistic (Γ ~ 100-1000, M jet < 10 -5 M )<br />
• Late Flaring (t flare /t GRB ~ 10 2 -10 4 ) ➙ Engine Active Long after GRB<br />
Swift XRT<br />
Nousek+ 2006; O’Brien+ 2006<br />
X-ray Afterglow
Long GRBs = Massive Stellar Death<br />
(Paczynski 98, Galama et al. 98, Bloom et al. 99, Pian et al. 06, Modjaz et al. 06, Woosley & Bloom 06)<br />
HST, Fruchter+ 2006<br />
GRB 030329 ⇔ SN 2003dh (BL Type Ic)<br />
Stanek+ 2003
Courtesy A. MacFadyen
MacFadyen & Woosley (1999)<br />
The Collapsar Model (Woosley 93)<br />
Energy : Accretion / Black Hole Spin<br />
Duration : Stellar Envelope In-Fall<br />
Late Flaring: Fall-Back Accretion?<br />
Bright Supernova: Accretion Disk Winds or<br />
(Extra Nickel) Delayed Black Hole<br />
Zhang, Woosley & Heger (2004)
What Distinguishes GRB Supernovae?<br />
Soderberg et al. 2006, 2007, 2009<br />
“GRB-SNe are not clearly distinguished from ordinary SNe Ibc either by optical<br />
luminosity or photospheric velocities.”
!<br />
Core Collapse with Magnetic Fields & Rotation<br />
(e.g. LeBlanc & Wilson 1970; Bisnovatyi-Kogan 1971; Akiyama et al. 2003)<br />
˙<br />
M IN !<br />
˙<br />
M OUT<br />
Collapsar Requirements:<br />
Angular Momentum<br />
Strong, Ordered Magnetic Field<br />
(e.g. Proga & Begelman 2003; McKinney 2006)<br />
Neutron Star Mass
Millisecond Magnetar Model (Usov 1992; Wheeler+ 2000)<br />
E Rot " 2 #10 52$<br />
P '<br />
& )<br />
% 1 ms(<br />
*2<br />
ergs<br />
Rapid Rotation ⇔ Efficient α-Ω Dynamo ⇔ Strong B-Field at P ~ 1 ms<br />
(Duncan & Thompson 1992; Thompson & Duncan 1993)<br />
!<br />
E "<br />
#10 49$<br />
P '<br />
& )<br />
% 1 ms(<br />
10 15 2<br />
$ '<br />
& ) ergs s<br />
% G(<br />
-1<br />
*4 BDip
Millisecond Magnetar Model (Usov 1992; Wheeler+ 2000)<br />
E Rot " 2 #10 52$<br />
P '<br />
& )<br />
% 1 ms(<br />
*2<br />
ergs<br />
Rapid Rotation ⇔ Efficient α-Ω Dynamo ⇔ Strong B-Field at P ~ 1 ms<br />
(Duncan & Thompson 1992; Thompson & Duncan 1993)<br />
!<br />
Galactic Magnetars exist as<br />
SGRs and AXPs…<br />
E "<br />
#10 49$<br />
P '<br />
& )<br />
% 1 ms(<br />
Magnetar<br />
10 15 2<br />
$ '<br />
& ) ergs s<br />
% G(<br />
-1<br />
*4 BDip<br />
…and can have massive<br />
progenitors<br />
Westerlund I: O7 Stars still present!<br />
Muno +06
Key Insight :<br />
(Thompson, Chang & Quataert 04)<br />
• Neutrinos Heat Proto-NS Atmosphere (e.g. ν e + n ⇒ p + e - )<br />
Burrows, Hayes, & Fryxell 1995<br />
⇒ Drives Thermal Wind Behind SN Shock<br />
(Duncan et al. 1986; Qian & Woosley 1996)<br />
Neutron Stars are Born Hot,<br />
Cool via ν-Emission:<br />
~10 53 ergs in τ KH ~ 10-100 s<br />
!<br />
M ˙ "10 #6 L $<br />
10 51 ergs s -1<br />
% (<br />
' *<br />
& )<br />
5 / 3<br />
% T ( $<br />
' *<br />
& 3 MeV)<br />
10 / 3<br />
M • s #1
Outflow Power (10 51 ergs s -1 )<br />
Proto-Magnetar Wind Evolution<br />
Metzger, Thompson, Quataert 2007, 2008<br />
B = 3x10 15 G, P 0 = 1 ms<br />
M NS = 1.2, 1.4, 2.0 M <br />
(from Pons et al. 1999)<br />
σ ~ Γ<br />
Non-<br />
Relativistic<br />
Relativistic<br />
(GRB)<br />
" ~ # = max ˙ E<br />
M ˙ c 2 $ B2 % 4<br />
L<br />
5/3<br />
T<br />
10/3<br />
&<br />
Ultra-Relativistic<br />
(Normal “Cold” Pulsar)
Collimation : The Tube of Toothpaste Effect<br />
Multi-Wavelength Crab Nebula<br />
PWN<br />
RADIO OPTICAL<br />
X-RAYS<br />
SNR<br />
PULSAR<br />
3C58<br />
(Chandra)
Collimation : The Tube of Toothpaste Effect<br />
Multi-Wavelength Crab Nebula<br />
PWN<br />
RADIO OPTICAL<br />
X-RAYS<br />
Ω<br />
SNR<br />
PULSAR WIND<br />
MAGNETIC FIELD<br />
ELONGATES NEBULA!<br />
(Begelman & Li 1992)<br />
PULSAR<br />
3C58<br />
(Chandra)<br />
Ω
Proto-Magnetar<br />
Jet Formation<br />
Assume<br />
Successful SN (35<br />
M ZAMS Prognenitor)<br />
B = 3 x 10 15 G,<br />
P 0 = 1 ms<br />
Inner BCs from<br />
Proto-NS Wind<br />
Calculations<br />
(Metzger+ 2007)<br />
Collimation via<br />
Inertial<br />
Confinement of<br />
Stellar Envelope<br />
(see also Uzdensky &<br />
MacFadyen 06)<br />
T = 1.6 s<br />
T = 3 s (Zoomed Out)<br />
T = 5 s<br />
Density Pressure Velocity<br />
Bucciantini+ 07,08,09
Next Step:<br />
Light Curves & Spectra<br />
σ ~ Γ<br />
Power (10 51 ergs s -1 )<br />
GRB Diversity: B 0, P 0, M NS<br />
10 16 G<br />
Internal Shocks<br />
P0= 1 ms<br />
3 10 15 G<br />
10 15 G<br />
Magnetic Reconnection<br />
Metzger & Giannios (in prep)<br />
Metzger, Thompson & Quataert 2008
Property<br />
Total Energy<br />
Lorentz Factor<br />
SN Association<br />
Collimation<br />
Duration<br />
Late Flaring<br />
Particle<br />
Composition<br />
Black Hole Vs. Magnetar<br />
Black Hole<br />
0.1 M acc c 2 (huge)<br />
???<br />
Delayed BH or<br />
Accretion Disk Wind<br />
Disks Produce Jets<br />
Stellar In-Fall Time<br />
Late-Time Fallback<br />
Pairs or Baryons?<br />
Proto-Magnetar<br />
E max ~ 3x10 52 ergs<br />
(max rotation rate)<br />
Γ ~ 10 2 - 10 3 for t~10-100 s<br />
Higher L γ ⇔ Higher Γ<br />
Neutron Stars Make<br />
Supernovae<br />
Collimation via Stellar<br />
Confinement (θ jet ~ 5 o )<br />
NS Cooling Phase (~10-300 s)<br />
Magnetar Remains!<br />
Baryons during first ~ 30-100<br />
seconds
Part II: Short-Duration GRB<br />
<strong>Central</strong> <strong>Engines</strong>
GRB050509b<br />
Short GRB Host Galaxies<br />
KECK Bloom+06<br />
SFR < 0.1 M yr-1 Berger +05<br />
z = 0.225<br />
Bloom+ 06<br />
GRB050724<br />
GRB050709<br />
z = 0.258<br />
SFR < 0.03 M yr -1<br />
z = 0.16<br />
SFR = 0.2 M yr -1<br />
HUBBLE Fox+05<br />
Berger+05
GRB050509b<br />
Short GRB Host Galaxies<br />
z = 0.225<br />
KECK Bloom+06<br />
SFR < 0.1 M yr-1 Berger +05<br />
Bloom +06<br />
No Supernova!<br />
• Lower redshift*<br />
(z ~ 0.1-1) GRB050724<br />
• Eiso ~ 10<br />
GRB050724<br />
49-51 ergs*<br />
• Older Progenitor<br />
Population (Consistent<br />
with tracing total stellar<br />
mass; Berger 09)<br />
GRB050709<br />
z = 0.258<br />
SFR < 0.03 M yr -1<br />
z = 0.16<br />
SFR = 0.2 M yr -1<br />
HUBBLE Fox+05<br />
Berger+05
Merging Compact Objects (NS-NS or BH-NS)<br />
Paczynski 1986; Goodman 1986; Eichler+1989; Narayan+ 1992, …<br />
Inspiral “Chirp”<br />
Gravitational Waves<br />
• Target for Advanced LIGO<br />
t = 0.7 ms<br />
t = 3 ms<br />
• Disk left behind w/ mass ~ 10 -3 - 0.1 M & size ~ 10-100 km<br />
• M ˙ ~ 10 ⇒ cooling via neutrinos: (τγ >>1, τν ~ 1 )<br />
"2 "10M• s -1<br />
Shibata & Taniguchi 2006
Accretion-Induced Collapse (AIC)<br />
• “Failed” Type Ia SN<br />
• Collapse of rapidly-rotating WD ⇒<br />
Disk around PNS: M disk ~ 10 -2 - 0.3 M <br />
• Evolution similar to NS merger disks<br />
(Metzger+ 08,09)<br />
Circinus X-1<br />
(Chandra)<br />
Neutron Star Circinus X-1<br />
Γ > 15 ! (Fender et al. 2004)
Similar Systems - Distinct Origins<br />
NS-NS / BH-NS<br />
Mergers<br />
Accretion-<br />
Induced<br />
Collapse<br />
BH<br />
M ~ 0.01-0.1 M <br />
R ~ 100 km<br />
NS<br />
consistent with short<br />
GRB durations
Short GRBs with Extended X-<strong>Ray</strong> Emission<br />
GRB050709<br />
GRB080503<br />
S EE /S GRB ~ 30<br />
Perley et al. 2008<br />
~25% of Swift <strong>Burst</strong>s (may be 2 classes)<br />
Energy 1-30 x Prompt Spike<br />
BATSE Examples (Norris & Bonnell 2006)
Local Disk Mass πΣr 2 (M )<br />
Evolution of the Remnant Disk<br />
Metzger, Piro, Quataert 2008, 2009 (see also Beloborodov 2009; Lee et al. 2009)<br />
1-D Time-Dependent Models<br />
(α viscosity; realistic ν-cooling)<br />
J = (GM • R) 1/ 2 M D
• α-Particle Formation<br />
Late-Time Outflows<br />
At t ~ 0.1-1 seconds: R ~ 500 km, M ~ 0.3 Minitial, initial,<br />
T ~ 1 MeV<br />
EBIND BIND ~ GM BH mn/2R /2R ~ 3 MeV nucleon<br />
ΔENUC NUC ~ 7 MeV nucleon -1<br />
nucleon -1<br />
• Thick Disks Marginally Bound<br />
(Narayan & Yi 94; Blandford & Begelman 99)<br />
BH<br />
} ⇒<br />
Powerful Winds<br />
Blow Apart<br />
Disk<br />
~20-40% of the Initial Disk is Ejected Back into Space!
Late-Time Activity from Fall-Back Accretion?
Late-Time Activity from Fall-Back Accretion?
-Process Nucleosynthesis in NS Merger Ejecta<br />
+<br />
a<br />
(Lattimer & Schramm 1974; Eichler et al. 1989; Metzger et al. 2009)<br />
!<br />
!<br />
VS.<br />
˙<br />
Q r" process ~ 1" 3 MeV/nuc/s<br />
E B ~ GM BH<br />
over t heat ~ t β ~ 1 s<br />
2a ~ 1 MeV/nuc t # & fall"back<br />
% (<br />
$ 1 s '<br />
"2 / 3
The Effects of r-Process Heating on Fall-back Accretion<br />
Metzger, Arcones, Quataert, Martinez-Pinedo 2009<br />
Either: Complete Suppression of Fall-Back after t ~ 1 sec<br />
OR “Gap” of Δt ~ seconds opened<br />
???
???
Magnetar Spin-Down<br />
Metzger, Quataert & Thompson 08<br />
Following:<br />
Accretion-Induced<br />
Collapse<br />
NS-NS Merger with<br />
long-lived NS remnant<br />
???<br />
Internal Shock Emission<br />
P0= 1 ms<br />
10 16 G<br />
3 10 15 G<br />
GRB060614 Overlaid<br />
10 15 G
Long-Duration GRBs:<br />
Summary<br />
• Black Holes and Proto-Magnetars both remain viable models<br />
• Magnetar model quantitatively explains (1) energy, (2) time<br />
scale, (3) mass-loading (Lorentz factor), (4) collimation<br />
• Renewed Challenge: Relate dE/dt, Γ, σ ⇒ γ-<strong>Ray</strong>s<br />
Short-Duration GRBs:<br />
• Swift Revolution: Afterglows and Host Galaxies<br />
• Merging Compact Objects Remains Promising Model<br />
– Accretion Disk Explodes at Late Times<br />
⇒ 100 second X-<strong>Ray</strong> Emission Remains a Major Problem<br />
• AIC: Promising Alternative Model
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