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TP Vancouver I 1
Relativity in Action –Relativity in Action –Gamma Ray BurstsGamma Ray BurstsTsvi Piran HU, Tsvi Piran HU, JerusalemJerusalem
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THE DISCOVERYTHE DISCOVERYGamma-Ray Bursts (GRBs) Short (few seconds) bursts of Gamma-Ray Bursts (GRBs) Short (few seconds) bursts of
100keV- few MeV100keV- few MeV were discovered accidentally by were discovered accidentally by
Klebesadal Strong and Olson in 1967 Klebesadal Strong and Olson in 1967
using the Vela satellites using the Vela satellites
(defense satellites sent to monitor (defense satellites sent to monitor
the outer space treaty). the outer space treaty). The discovery was reported for the The discovery was reported for the
first time only in 1973.first time only in 1973.
• There was an “invite prediction”. There was an “invite prediction”. S. Colgate was asked to predict S. Colgate was asked to predict GRBs as a scientific excuse for the GRBs as a scientific excuse for the launch of the Vela Satellites launch of the Vela Satellites
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GRBsGRBs
Compton-GROCompton-GRO
Duration 0.01-100sDuration 0.01-100s Two populations (long and short)Two populations (long and short)
~ 1 BATSE burst per day~ 1 BATSE burst per day - (a local rate of ~2 Gpc- (a local rate of ~2 Gpc-3-3 yr yr-1 -1 )) ~100keV photons~100keV photons Non thermal SpectrumNon thermal Spectrum
(very high energy tail, (very high energy tail, up to GeV, 500GeV?)up to GeV, 500GeV?) Rapid variability (less than 10ms)Rapid variability (less than 10ms) Cosmological Origin Cosmological Origin The brightness of a GRB is comparable to the brightness of the rest The brightness of a GRB is comparable to the brightness of the rest
of the Universe combined.of the Universe combined.
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GRB 971214GRB 971214
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GRBs and RelativityGRBs and Relativity
GRBs involve the fastest GRBs involve the fastest macroscopic relativistic macroscopic relativistic motion observed so far motion observed so far
((>100)>100)
GRBs signal (most GRBs signal (most likely) the formation likely) the formation
of newborn black of newborn black holes.holes.
Sources of GRBs Sources of GRBs (merging NS or (merging NS or
Collapsars) are also Collapsars) are also sources of Gravitational sources of Gravitational
radiationradiation
GRBs are the best GRBs are the best cosmological cosmological
indicators known indicators known today for the early today for the early (z~5-10) universe.(z~5-10) universe.
GRBs are the brightest and most luminous objects known today.GRBs are the brightest and most luminous objects known today.
GRBs are the most relativistic objects known today.GRBs are the most relativistic objects known today.
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BATSE on Compton -BATSE on Compton -
GRO GRO (Fishman et. al.)(Fishman et. al.)
discovered that the discovered that the
distribution of GRBs distribution of GRBs
is isotropic:is isotropic:
The flux distribution (paucity of weak bursts) shows that The flux distribution (paucity of weak bursts) shows that the bursts cannot be very nearby in the disk:the bursts cannot be very nearby in the disk:
GRBs areGRBs are Cosmological Cosmological By now there are redshift measurements for the afterglow By now there are redshift measurements for the afterglow of two dozen bursts. of two dozen bursts.
19911991:: GRBs are CosmologicalGRBs are Cosmological
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Revised Energy EstimatesRevised Energy EstimatesThe observed fluences are ~10The observed fluences are ~10-7 -7 - 10- 10-5 -5 ergs/cmergs/cm22
24
)1(
Ld
zEF
Cosmological Cosmological corrections.corrections.
Galactic Halo Galactic Halo modelsmodels
““standard standard candles ?”candles ?”
(E)
z~1 z~1 E~10 E~105252ergs ergs GRBs are the GRBs are the (electromagnetically) (electromagnetically) most luminous objects most luminous objects in the Universe. in the Universe. For a few second the For a few second the luminosity of a GRB is luminosity of a GRB is comparable to the comparable to the luminosity of the rest of luminosity of the rest of the Universe.the Universe.
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Implications of 10Implications of 105252ergsergs
Need ultrarelativistic motion to get 10Need ultrarelativistic motion to get 105252erg erg out from a compact source within such a out from a compact source within such a short time scale.short time scale.
The The
FIREBALL FIREBALL
MODELMODELTP Caltech 2001 12
The Fireball ModelThe Fireball Model
compact sourcecompact source
Relativistic Relativistic ParticlesParticles>100>100oror PoyntingPoynting fluxflux
ShocksShocks
rays
~ 10~ 107 7 cmcm
Goodman; Goodman; PaczynskiPaczynski; ; Shemi Shemi & Piran, & Piran, NarayanNarayan, , PaczynskiPaczynski & Piran; & Piran; MeszarosMeszaros & Rees,& Rees,
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Implications of 10Implications of 105151 ergs - ergs -The Compactness Problem: The Compactness Problem: ee++ee--
sec sec R R cc = 3 10 = 3 109 9 cm.cm. EE 10 105151ergs.ergs.
== nn R R 10101515
Expect No Photons above 500keV!Expect No Photons above 500keV!
BUTBUT::
Need New Need New Physics?Physics?
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The SolutionThe Solution
Relativistic MotionRelativistic MotionRRccEEphph (obs) = (obs) = EEphph (emitted) (emitted)
= = nn RR
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Relativistic effects can influence the observed time Relativistic effects can influence the observed time scale in GRBsscale in GRBs (Ruderman, 75; Krolik & Pier, 89).(Ruderman, 75; Krolik & Pier, 89).
High Energy Density in a Small Region High Energy Density in a Small Region A Fireball:A Fireball: Pure radiation fireball Pure radiation fireball thermal radiation thermal radiation
(Goodman, 86; Paczynski 86).(Goodman, 86; Paczynski 86). BUTBUT Baryonic load Baryonic load relativistic Baryonic flow: relativistic Baryonic flow:
(Shemi & Piran, 90).(Shemi & Piran, 90). SHOCKS:SHOCKS: Extraction of the kinetic energy of the Extraction of the kinetic energy of the
Baryons by External shocks Baryons by External shocks (Meszaros and Rees, 1992) (Meszaros and Rees, 1992)
or internal shocksor internal shocks (Narayan, Paczynski &Piran 1992; (Narayan, Paczynski &Piran 1992; Paczynski and Xu, 1992; Meszaros and Rees, 1994).Paczynski and Xu, 1992; Meszaros and Rees, 1994).
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The Fireball ModelThe Fireball Model
compact sourcecompact source
Relativistic Relativistic ParticlesParticles>100>100or Poynting fluxor Poynting flux
ShocksShocks
rays
~ 10~ 107 7 cmcm
Goodman; Paczynski; Shemi & Piran, Goodman; Paczynski; Shemi & Piran, Narayan, Paczynski & Piran; Meszaros & Rees,Narayan, Paczynski & Piran; Meszaros & Rees,
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Supernova Remnants (SNRs) - Supernova Remnants (SNRs) - the Newtonian Analoguethe Newtonian Analogue
~ 10 solar masses are ~ 10 solar masses are ejected at ~10,000 ejected at ~10,000 km/sec during a km/sec during a supernova explosion. supernova explosion.
The ejecta is slowed The ejecta is slowed down by the interstellar down by the interstellar medium (ISM) emitting medium (ISM) emitting x-ray and radio for x-ray and radio for ~10,000 years.~10,000 years.
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Gamma-Ray Burst: Gamma-Ray Burst: 3 Stages3 Stages
11) ) Compact Source, E>10Compact Source, E>105252ergerg
2) Relativistic Kinetic Energy2) Relativistic Kinetic Energy
3) Kinetic Energy to Internal Energy to 3) Kinetic Energy to Internal Energy to RadiationRadiation=GRB=GRB
The Compact Source is Hidden
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Temporal Variability- the Second ClueTemporal Variability- the Second Clue T<1sec, T~100T<1sec, T~100 N=T/N=T/T>100T>100
•Variability - a measure Variability - a measure of the luminosity of the luminosity (Fenimore et al, 99; (Fenimore et al, 99; Riechart et al, 00)Riechart et al, 00) Distance indicator!Distance indicator!
• External shocks External shocks cannot produce the cannot produce the observer variability in observer variability in
the light curvesthe light curves (Sari & (Sari & Piran, 97, Fenimore et al, Piran, 97, Fenimore et al,
97).97).
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External vs. Internal ShocksExternal vs. Internal Shocks
External shocks are shocks between the External shocks are shocks between the relativistic ejecta and the ISM - just like in relativistic ejecta and the ISM - just like in SNRs.SNRs.
Internal shocks occur Internal shocks occur
between different between different
shells within the shells within the
relativistic ejecta.relativistic ejecta.
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• = R= R//cc= =
//cc//cc=T=T• The observed light curve reflects the activity of the The observed light curve reflects the activity of the
“inner engine”. “inner engine”. Need TWO time scales. • Quiescent Periods within long bursts suggest that the Quiescent Periods within long bursts suggest that the
source is inactive for of dozen seconds withinsource is inactive for of dozen seconds within long bursts long bursts (Nakar and Piran, 2000).(Nakar and Piran, 2000).
=cT=cT
==cT
Internal Internal ShocksShocks
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((most)most)** GRBs cannot GRBs cannot originate from an originate from an
EXPLOSIONEXPLOSION..This rules out many models:This rules out many models:
•Evaporating mini black holes.Evaporating mini black holes.
•NS -> BHNS -> BH
•NS -> strange starNS -> strange star
•Vacuum InstabilityVacuum Instability
•……………………..
* * Highly variable (there is a small group of Highly variable (there is a small group of smooth bursts which can be explosive)smooth bursts which can be explosive)
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• Internal shocks can convert only a fractionInternal shocks can convert only a fraction of of the kinetic energy to radiationthe kinetic energy to radiation
(Sari and Piran 1997; Mochkovich et. al., 1997; (Sari and Piran 1997; Mochkovich et. al., 1997; Kobayashi, Piran & Sari 1997).Kobayashi, Piran & Sari 1997).
It should be followed by additional emissionIt should be followed by additional emission..
=cT=cT
==cT
Internal Internal Shocks Shocks AfterglowAfterglow
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11) ) Compact Source, E>10Compact Source, E>105151ergerg
2) Relativistic Kinetic Energy2) Relativistic Kinetic Energy
3) Radiation due to Internal shocks = GRBs3) Radiation due to Internal shocks = GRBs
4) Afterglow by external shocks4) Afterglow by external shocks
Gamma-Ray Burst:4 Stages
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InnerEngine
Relativistic Wind
The Internal-External Fireball ModelThe Internal-External Fireball Model
There are There are no direct observationsno direct observations of the inner engine. of the inner engine.The The -rays light curve-rays light curve contains the contains the best evidencebest evidence on on the inner engine’s activity.the inner engine’s activity.
ExternalShock
Afterglow
InternalShocks
-rays
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GRB - The MovieGRB - The MovieFour Initialshells
ISM
Afterglow - other colors
GRB -yellow flash
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Afterglow – The Second Afterglow – The Second RevolutionRevolution
The Italian/Dutch The Italian/Dutch
satellitesatellite BeppoSAXBeppoSAX
discovered x-ray afterglowdiscovered x-ray afterglow
on 28 February 1997on 28 February 1997
(Costa et. al. 97)(Costa et. al. 97). . Immediate discovery of Immediate discovery of OpticalOptical
afterglow afterglow (van Paradijs et. al 97).(van Paradijs et. al 97).
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The Radio AfterglowThe Radio Afterglow of of GRB970508 GRB970508 (Frail et. al, 97).(Frail et. al, 97).
Variability:Variability: Scintillations Scintillations (Goodman, 97; Frail et al 97)(Goodman, 97; Frail et al 97) Size afterSize after one month one month 10101717cm.cm.
Rising Spectrum at low frequencies:Rising Spectrum at low frequencies: Self absorptionSelf absorption ( (Katz & Piran, 97; Frail et al 97Katz & Piran, 97; Frail et al 97)) Size after one Size after one
monthmonth10101717cm.cm. Relativistic Motion!!! Relativistic Motion!!! (but (but since this is a long time after the since this is a long time after the
explosionexplosion
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A crash Course in ScintillationsA crash Course in Scintillations
Scintillations determine the size of the source in a Scintillations determine the size of the source in a model independent way. The size (~10model independent way. The size (~101717cm) is in a cm) is in a perfect agreement with the prediction of the perfect agreement with the prediction of the Fireball model.Fireball model.
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Relativistic Hydrodynamics of Relativistic Hydrodynamics of the Fireabll Modelthe Fireabll Model
• Ehud Cohen (Hebrew U)Ehud Cohen (Hebrew U)• Jonathan Granot (Hebrew U)Jonathan Granot (Hebrew U)• Philip Hughes (Michigan U) Philip Hughes (Michigan U) • Pawan Kumar (IAS, Princeton)Pawan Kumar (IAS, Princeton)• Mark Miller (Washington U)Mark Miller (Washington U)• Ehud Nakar (Hebrew U)Ehud Nakar (Hebrew U)• Ramesh Narayan (Harvard) Ramesh Narayan (Harvard)
Re’em Sari (Caltech) Re’em Sari (Caltech) • Amotz Shemi (Tel Aviv U)Amotz Shemi (Tel Aviv U)• Wai Mo Suen (Washington U)Wai Mo Suen (Washington U)
Tsvi PiranTsvi PiranHU, Jerusalem ISRAELHU, Jerusalem ISRAEL
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The Acceleration PhaseThe Acceleration Phase
Consider a dense spherical concentration Consider a dense spherical concentration of energy in the form of radiation and of energy in the form of radiation and some matter – a Fireball.some matter – a Fireball.
radMatterrad EEEE 0
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02
022
0
0
00
340
/ :Result Final
)/(
:EvolutionEnergy
:depth Optical
20 :Transition
)/(
)/( :Evolution
)3/4( :Conditions Initial
EMc
RRMcMcE
EEE
Rn
keVT
RR
RRTT
RaTE
Matter
Matterrad
Te
ee
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Afterglow TheoryAfterglow Theory
Hydrodynamics:Hydrodynamics: deceleration of thedeceleration of the
relativistic shell by collision with the surrounding mediumrelativistic shell by collision with the surrounding medium (Blandford & McKee 1976)(Blandford & McKee 1976) (Meszaros & Rees 1997, Waxman 1997, Sari 1997, Cohen, Piran & (Meszaros & Rees 1997, Waxman 1997, Sari 1997, Cohen, Piran & Sari 1998)Sari 1998)
Radiation:Radiation: synchrotron + IC (?)synchrotron + IC (?)
(Sari, Piran & Narayan 98)(Sari, Piran & Narayan 98)
Clean, well defined problem.Clean, well defined problem.
Few parameters:Few parameters:
E, n, p, E, n, p, ee, , BB
initialinitialshellshell ISMISM
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Adiabaticity: Adiabaticity:
Arrival time:Arrival time:
Energy densities: Energy densities:
Electron distribution:Electron distribution:
223220 )3/4( cRMcE
22/ Rtobs
220 cnee eee
220 cnee BBB
ep en
minfor )(
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The Blandford McKee solutionA relativistic analog of Sedov Taylor
initialinitialshellshell ISMISM
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Radiation ProcessesRadiation Processes Synchrotron radiation from a power law
electron distribution E-p, (p 2.5)
syn() = eB2/(mec) m = syn(min) 10
210
310
410
510
-6
10-5
10-4
10-3
10-2
10-1
100
E
N(E)
Emin
10-2
10-1
100
101
102
10-1
100
101
E-p -1/3
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Fast and Slow Cooling
Fast Cooling
102
103
104
105
10-4
10-3
10-2
10-1
100
E
N(E)
Ec
Slow Cooling
PPsynsyn=(4/3)=(4/3)T T c Uc UBB 2 2
cc = (3 m = (3 mee c)/(4 c)/(4 TT U UBB t) t)
cc = = synsyn((cc))
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The Simplest Synch Spectrum (I)The Simplest Synch Spectrum (I)(Sari Piran & Narayan 1998)(Sari Piran & Narayan 1998)
Fast Cooling Fast Cooling
((cc < < mm))
Low energyLow energy
FF -1/3-1/3
a: a: n neeaa((aa) L = 1) L = 1
Synch selfSynch self
AbsorptionAbsorption
Fast Cooling during the Fast Cooling during the High Energy FHigh Energy F -p/2-p/2
early afterglow (first half hour)early afterglow (first half hour)
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The Simplest Synch Spectrum (II)The Simplest Synch Spectrum (II)
Slow Cooling during most of the afterglow (after half Slow Cooling during most of the afterglow (after half hour)hour)
((cc > > mm))
Low energyLow energy
FF -1/3-1/3
a: a: n neeaa((aa) L = 1) L = 1
Very low energyVery low energy
Synch self AbsorptionSynch self Absorption
High Energy FHigh Energy F -p/2-p/2
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Light Curves and Spectrum of Light Curves and Spectrum of the BM-Synch Afterglowthe BM-Synch Afterglow
FF
For spherical expansion:For spherical expansion: For For cc =(p-1)/2 ; =(p-1)/2 ; =(3p-3)/4 ; =(3p-3)/4 ; =3=3 For For cc = p/2 ; = p/2 ; =(3p-2)/4 ; =(3p-2)/4 ;
For GRB970508: For GRB970508:
=1.12, =1.12, consistent with consistent with
p=2.2-2.5 and with p=2.2-2.5 and with cc ..
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Comparison with ObservationsComparison with Observations(Sari, Piran & Narayan 98; Wijers & Galama 98; Granot, (Sari, Piran & Narayan 98; Wijers & Galama 98; Granot,
Piran & Sari 98)Piran & Sari 98)
Radio observationsRadio observations
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AFTERGLOW SLOPESAFTERGLOW SLOPES
GRB
970508 -1.2
980613 -1.3990123 -1.13 -1.7990510 -0.88 -2.5990705 < -1.4990712 -1.05991208 -2.991216 -1.200301C -1.3 -2.7000418 -1.3000926 -1.65 -2.5
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BUTBUT
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ComplicationsComplications Wind Wind (Chavalier & Li 99, Panaitescu and (Chavalier & Li 99, Panaitescu and
Kumar,00) Kumar,00) : :
(still a spherical cow).(still a spherical cow). Sideway Expansion (an expanding jet) Sideway Expansion (an expanding jet)
(Rhoads 99, Sari Piran Halpern 99, Panaitescu and (Rhoads 99, Sari Piran Halpern 99, Panaitescu and
Meszaros 99)Meszaros 99) : :
sRRn generalin or 20
q generalin or 1
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Further ComplicationsFurther Complications
A jet into a wind A jet into a wind (Panaitescu and Kumar 00)(Panaitescu and Kumar 00)
A collimated jet A collimated jet
Inverse ComptonInverse Compton (Panaitescu and Kumar 00, (Panaitescu and Kumar 00, Esin and Sari,00)Esin and Sari,00)
120 and Rn
q generalin or 1 rRR
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Generalized hydro relationsGeneralized hydro relationsqrsRnRMcE 2223
023222
0
)4228/()23( rsqrsobst
This relation is now plugged into the frequencies and This relation is now plugged into the frequencies and fluxes estimate and one obtains an asymptotic light curcefluxes estimate and one obtains an asymptotic light curce
22/ Rtobs
)23/()22( rsqR R~const for q=1 (jet)R~const for q=1 (jet)
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JETS and BEAMINGJETS and BEAMING
Jets with an opening angle Jets with an opening angle expand forwards until expand forwards until and then and then expand sideways rapidlyexpand sideways rapidly
lowering quickly the observed flux lowering quickly the observed flux (Piran, 1995; Rhoads, 1997; (Piran, 1995; Rhoads, 1997; Wijers et al, 1997; Panaitescu & Meszaros 1998).Wijers et al, 1997; Panaitescu & Meszaros 1998).
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Schematic Jet ExpansionSchematic Jet Expansion
Four Initialshells
ISM
Afterglow - other colors
GRB -yellow flash
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Light Curves from a JetLight Curves from a Jet
Fast expansion Fast expansion Slow expansionSlow expansion )3/( cv )( cv
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The Synchrotron - Power Law The Synchrotron - Power Law Afterglow Model from a JetAfterglow Model from a Jet FF
For spherical expansion:For spherical expansion: For For cc =(p-1)/2 ; =(p-1)/2 ; =(3p-3)/4 ; =(3p-3)/4 ; =3=3 For For cc = p/2 = p/2 =(3p-2)/4 ; =(3p-2)/4 ;
For a jet expanding sideways For a jet expanding sideways (Rhoads, 1997, Sari Piran (Rhoads, 1997, Sari Piran Halpreen, 1999)Halpreen, 1999):: =p=p For For cc =(p-1)/2 ; =(p-1)/2 ; =2=2 For For cc = p/2 ; = p/2 ; =2=2
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GRB 990510 - GRB 990510 - Another Jet!Another Jet!
11
ttbreakbreak = 1.2 days = 1.2 days jet angle = 4 jet angle = 4o o FromFrom Harrison et al 1999Harrison et al 1999
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Redshift and Redshift and Energy Energy DeterminationDetermination
GRBGRB ZZ E (E (×× 10 105151))
970228970228 0.6950.695 22.422.4
970508970508 0.8350.835 5.465.46
970828970828 0.9580.958 220220
971214971214 3.4123.412 211211
980613980613 1.0961.096 5.675.67
980703980703 0.9670.967 60.160.1
990123990123 1.61.6 1440
990506990506 1.31.3 854854
990510990510 1.6191.619 178178
990705990705 0.840.84 270270
990712990712 0.4330.433 5.275.27
991208991208 0.7060.706 147147
991216991216 1.021.02 535535
000131000131 4.5 11601160
000131c000131c 2.0342.034 46.446.4
000418000418 1.1191.119 82.082.0
000926000926 2.0372.037 297297
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The Energy Crisis?
45
47
49
51
53
55
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1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Lo
g
( E )
(E)
971214971214 990123990123
Totani’s prediction for the energy of GRBs
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The Resolution of the Energy CrisisThe Resolution of the Energy Crisis
EEtottot -- The total energy The total energy
EEisoiso--Observed (iostropic) Observed (iostropic) ray energyray energy
isotot EE 1
isotot EEE 2
211
Beaming:Beaming:EE- Actual - Actual ray energyray energy
The two most powerful BeppoSAX bursts are The two most powerful BeppoSAX bursts are jets (Sari, Piran & Halpern; 1999).jets (Sari, Piran & Halpern; 1999).
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The Energy Crisis?The Energy Crisis?
45
47
49
51
53
55
57
59
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Lo
g
( E )(E
)
971214971214 990123990123
Prediction for the energy of GRBs
What goes What goes up must up must go down go down
e.g. e.g. NASDAQNASDAQ
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Constant ENERGYConstant ENERGY
E E 10105151 erg erg(Frail et al, 01; Panaitescu and Kumar 01)(Frail et al, 01; Panaitescu and Kumar 01)
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Numerical SimulationsNumerical SimulationsJonathan Granot (Hebrew U), Mark Miller (Washington U)Jonathan Granot (Hebrew U), Mark Miller (Washington U)Wai Mo Suen (Washington U), Philip Hughes (Michigan U)Wai Mo Suen (Washington U), Philip Hughes (Michigan U)
Why is it not trivial?Why is it not trivial? A flying pancake.A flying pancake. Extremely relativistic Extremely relativistic
motion.motion. Because of the time Because of the time
dependance it is much more dependance it is much more difficult than “standard” difficult than “standard” relativistic “jet” simulations.relativistic “jet” simulations.
2/ RR
cv
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AMR (Adaptive Mesh Refinement) AMR (Adaptive Mesh Refinement) Relativistic hydroRelativistic hydro code code..
A test with a BM A test with a BM profileprofile
Density profile with a Density profile with a high level mesh high level mesh
structurestructure
Convergence test by comparing different refinment levelsConvergence test by comparing different refinment levels
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The Initial Data - A slice from The Initial Data - A slice from a BM solution:a BM solution: =0.2; E=0.2; E5252=n=n00=1=1
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The Density Profile and the Velocity FieldThe Density Profile and the Velocity Field
t=0t=0 t=100t=100
t=200t=200 t=300t=300
t=400t=400 t=500t=500
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Conditions at the end of the Conditions at the end of the computationcomputation
EmisivityEmisivity Lorentz FactorLorentz Factor
DensityDensity Velocity FieldVelocity Field
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EmissivityEmissivity
Lorentz FactorLorentz Factor
DensityDensity
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Slow Sideways ExpansionSlow Sideways Expansion
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A refined BM-Synch ModelA refined BM-Synch ModelGranot, Piran & Sari 98a,b; Granot, Piran & Sari 98a,b;
Waxman & Gruzinov 98Waxman & Gruzinov 98
Emission is from an “egg”Emission is from an “egg”
shaped object with an shaped object with an
opening angle opening angle -1-1
Smooth SpectrumSmooth Spectrum
Images at different frequenciesImages at different frequencies
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But a Sharp But a Sharp (Not (Not
Achromatic)Achromatic) Break! Break!
* * synch emission does not include the effects of cooling.synch emission does not include the effects of cooling.
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Orphan Afterglows – Non observed so far
Orphan Orphan AfterglowAfterglow
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Uniform Structured Jet?(Rossi et al 02)
If E(If E(we will also see a jet break but we will also see a jet break but now the interpreted angle will correspond to now the interpreted angle will correspond to obsobs the observer viewing angle relative to the observer viewing angle relative to
the center of the jet. the center of the jet. This implies much more energy and much This implies much more energy and much
fewer bursts. It also implies different and fewer bursts. It also implies different and fewer “orphan afterglows”. fewer “orphan afterglows”.
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GRB Remnants (GRBRs)GRB Remnants (GRBRs)Ayal & Piran Ap J. 2001Ayal & Piran Ap J. 2001
• GRB involves ejection of ~10GRB involves ejection of ~105151ergs in kinetic ergs in kinetic energy into the ISM.energy into the ISM.
• This is similar to supernovae that produce SNRsThis is similar to supernovae that produce SNRs• How will a GRB Remnant (GRBR) look How will a GRB Remnant (GRBR) look
thousands of years AB (after burst)?thousands of years AB (after burst)?• Can we distinguish a GRBR from a SNR?Can we distinguish a GRBR from a SNR?• Search for the signature of GRB beaming in the Search for the signature of GRB beaming in the
GRBR.GRBR.
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The GRB and the AfterglowThe GRB and the Afterglow
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The Newtonian PhaseThe Newtonian Phase
• Newtonian transition.Newtonian transition.
• Sedov regime (energy Sedov regime (energy of ejecta and ISM mass of ejecta and ISM mass dominates (self similar in dominates (self similar in the spherical case).the spherical case).
• Shells mergeShells merge
• Spherical RemnantSpherical Remnant
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DEM L316 a GRBR or a Double SNR?DEM L316 a GRBR or a Double SNR?
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Initial conditionsInitial conditions
In the Sedov regime the late time results are insensitive to In the Sedov regime the late time results are insensitive to uncertainties in the initial conditions. We need only uncertainties in the initial conditions. We need only approximate initial conditions.approximate initial conditions.
rad (0.3rad-3rad)rad (0.3rad-3rad)
•Unknown energy and density distribution within the Unknown energy and density distribution within the ejecta.ejecta.
3/20
3/11
3/1510 )/( pc3.0~ cvnER
RR00
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The The parameterparameter
DefineDefine::
6/5
3/1051
3
2
)/(yr 05.0~
where
/
t
nEt
RM
EcM
shell
shell
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ResultsResults
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r
4
3/1351
106.9at
)cm1/)(ergs10/( pc 12
nErz xy
5/239.03/12 vs.)( tRtzrxy
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Results:Results:
• Shells collide at Shells collide at ~(1-5)~(1-5)101033. . t ~ (50-250) yr (Et ~ (50-250) yr (E5151/n)/n)1/31/3 R~4pc (ER~4pc (E5151/n)/n)1/31/3
• GRBR becomes spherical at GRBR becomes spherical at ~10~1055. . t ~ 3t ~ 3101033 yr (E yr (E5151/n)/n)1/3 1/3 R~12pc (ER~12pc (E5151/n)/n)1/31/3
• The expected number of non-spherical GRBRs is The expected number of non-spherical GRBRs is 0.5 (f0.5 (fbb/0.002)/0.002)-1-1 (E (E5151/n)/n)1/3 1/3 per galaxy per galaxy
• ~ 20 non spherical GRBRs up to 10 Mpc ~ 20 non spherical GRBRs up to 10 Mpc with angular sizes ~1.2with angular sizes ~1.2marcsec .marcsec .
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A Spherical Underlying SNA Spherical Underlying SN• v= dR/dt ~2(pc/yr) v= dR/dt ~2(pc/yr) -2/3-2/3..• A SN shell with v~10A SN shell with v~1044 km/sec will catch the GRBR shell at km/sec will catch the GRBR shell at
• ~ 3000 ;~ 3000 ;• t~150 t~150 yr (Eyr (E5151/n)/n)1/31/3 ; ;
• R~4pc (ER~4pc (E5151/n)/n)1/31/3 . .• Namely around the time of the two shell collision.Namely around the time of the two shell collision. • The non spherical structure will be destroyed.The non spherical structure will be destroyed.
• The number of non spehrical GRBRs is smaller by a factor The number of non spehrical GRBRs is smaller by a factor of 10 and the size is smaller by a factor of 3 if there is an of 10 and the size is smaller by a factor of 3 if there is an underlying spherical SNR with Eunderlying spherical SNR with ESNSNEEGRB GRB ..
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• The closest morphology is The closest morphology is at at ~10~1033..
• But using the observedBut using the observed
mass ~5000 Mmass ~5000 Moo and and
energy ~ 5energy ~ 510105050ergsergs of DEM L316 we findof DEM L316 we find m~7m~7101055. . • A GRBR would have been A GRBR would have been spherical at this stagespherical at this stage
What about DEM L316?What about DEM L316?
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Implications of Implications of the Fireball the Fireball
ModelModel
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Clues on the Inner Engine Clues on the Inner Engine The inner source is hidden. The observations The inner source is hidden. The observations
reflect only the conditions at the fireball.reflect only the conditions at the fireball. EEtottot~ 10~ 105151 ergs ergs
t < 10t < 10-2-2 sec sec T ~ 30 secT ~ 30 sec
~ 200 (“dirty”)~ 200 (“dirty”) Jets ~ 2Jets ~ 2o o - 5- 5oo
Rate 10Rate 10-5-5 /yr/galaxy /yr/galaxy
A compact ObjectA compact Object A compact ObjectA compact Object Prolonged activity: Prolonged activity: >>an accretion disk ?an accretion disk ? Baryonic Flow ?Baryonic Flow ? Lower energy, higher Lower energy, higher
rates, orphan afterglowsrates, orphan afterglows A rare phenomenonA rare phenomenon
Most likely powered by accretion onto a Most likely powered by accretion onto a newborn black holenewborn black hole
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Routes to a Routes to a BH-Disk-JetBH-Disk-Jet
Different routes can lead to Different routes can lead to a Black-hole -disk-jet a Black-hole -disk-jet system:system:
NS-NS mergerNS-NS merger BH-NS mergerBH-NS merger BH-WD mergerBH-WD merger NS/BH-He core mergerNS/BH-He core merger CollapsarCollapsar
Davies et al , 94Davies et al , 94
Woosley et al, 99Woosley et al, 99
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Evidence for Supernova Evidence for Supernova association with GRBsassociation with GRBs
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Evidence for Supernova Evidence for Supernova association with GRBsassociation with GRBs
Association of SN98bw and GRB980425 with a Association of SN98bw and GRB980425 with a similar type of SN in GRB030329similar type of SN in GRB030329
Late red bumps in light curves of GRB980326 and Late red bumps in light curves of GRB980326 and GRB970228 and several other afterglows.GRB970228 and several other afterglows.
Location:Location: Association of GRBs with star forming regions.Association of GRBs with star forming regions. Association of GRBs with central regions of Association of GRBs with central regions of
galaxiesgalaxies
Iron lines indicating large ~0.5MIron lines indicating large ~0.5Moo of Fe. of Fe.
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Jet Propagation through a stellar Jet Propagation through a stellar envelope (MacFadyen et al. )envelope (MacFadyen et al. )
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Neutron star merger Rosswog et al., 03 Neutron star merger Rosswog et al., 03
Newtonian SPH with accurate EOS and some neutrino Newtonian SPH with accurate EOS and some neutrino transport. GW backreaction included. transport. GW backreaction included.
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Accretion disks in GRBsAccretion disks in GRBs(Narayan, Piran & Kumar 2001):(Narayan, Piran & Kumar 2001):
•Need 10Need 105151ergs ergs mmdd ~ 10 ~ 10-3-3 Mo Mo
•Accretion time, tAccretion time, taccacc, is the , is the
duration of the burst.duration of the burst.
•In CDAF (Convection dominated In CDAF (Convection dominated accretion flow) most of the matter accretion flow) most of the matter is ejected back to infinity at slow is ejected back to infinity at slow velocities – accretion efficiency is velocities – accretion efficiency is very low.very low.
•Accretion is effective in NDAF Accretion is effective in NDAF (Neutrino dominated accretion (Neutrino dominated accretion flow) – but NDAFs are very small flow) – but NDAFs are very small rroutout<50r<50rgg
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Convection dominated accretion flow – Convection dominated accretion flow – Igumenenshev Abraowicz and Narayan Igumenenshev Abraowicz and Narayan
Most of the matter is ejected to infinity Most of the matter is ejected to infinity (Newtonian Calculations)(Newtonian Calculations)
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ImplicationsImplications Need large disks (100-1000rNeed large disks (100-1000rgg) to produce ) to produce
long duration jets.long duration jets. Need small disks (10rNeed small disks (10rgg) to produce short ) to produce short
bursts.bursts.
Large disks (100-1000rLarge disks (100-1000rgg) are inefficient and ) are inefficient and cannot produce 10cannot produce 105151 ergs. ergs.
Small disks (10rSmall disks (10rgg) are efficient) are efficient..
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Implications of Implications of Accretion TheoryAccretion Theory(Narayan, Piran, Kumar 00)(Narayan, Piran, Kumar 00)
Large CDAFs are inefficient and cannot produce Large CDAFs are inefficient and cannot produce GRBs. Models with large accretion disks (He star GRBs. Models with large accretion disks (He star –NS/BH; WD-NS/BH; etc..) are ruled out.–NS/BH; WD-NS/BH; etc..) are ruled out.
A Collapsar might produce a small NDAF disk in A Collapsar might produce a small NDAF disk in which the long duration is determined by the infall which the long duration is determined by the infall time and NOT by the accretion time.time and NOT by the accretion time.
NS mergers produce small NDAF disks in which NS mergers produce small NDAF disks in which the duration is determined by the accretion time.the duration is determined by the accretion time.
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Routes to a Routes to a BH-Disk-JetBH-Disk-Jet
Different routes can lead to Different routes can lead to a Black-hole -disk-jet a Black-hole -disk-jet system:system:
NS/BH-NS mergerNS/BH-NS merger BH-WD mergerBH-WD merger NS/BH-He core mergerNS/BH-He core merger CollapsarCollapsar
Davies et al , 94Davies et al , 94
Woosley et al, 99Woosley et al, 99
shortshort
LongLong
- LONG- LONG
- SHORT- SHORT
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NY Times May 99NY Times May 99
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Sources of GRBs (NS mergers Sources of GRBs (NS mergers -- short -short - or Collapsars or Collapsars - long- long) are sources of ) are sources of
Gravitaional RadiationGravitaional Radiation
One One longlong GRBs per 10 GRBs per 104 (4 (/0.1)/0.1)-2 -2 years per galaxy. years per galaxy. Beaming factorBeaming factor
One observed long burst per year at D~600 One observed long burst per year at D~600 Mpc.Mpc. One One unobservedunobserved burst per year at D~135 burst per year at D~135 ((/0.1)/0.1) 2/3 2/3 Mpc.Mpc. ShortShort bursts are most likely at z<0.5 with one short burst bursts are most likely at z<0.5 with one short burst
per 10per 103 (3 (/0.1)/0.1)-2 -2 years per galaxy. years per galaxy. One observed One observed shortshort burst per year at D~250 Mpc. burst per year at D~250 Mpc. One One unobservedunobserved shortshort burst per year at D~80 burst per year at D~80((/0.1)/0.1)2/32/3Mpc. Mpc.
Is this the rate of NS mergers?Is this the rate of NS mergers?
