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Perspectives on Gamma Ray Bursts (GRBs) - Enigma and a Tool Tsvi Piran Racah Institute of Physics, The Hebrew University Tuesday, February 7, 2012 Once or twice a day we see a burst of low energy gamma-rays from the outer space lasting

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Perspectives on Gamma Ray Bursts (GRBs) - Enigma and a Tool

Tsvi Piran

Racah Institute of Physics, The Hebrew University

Tuesday, February 7, 2012

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Once or twice a day we see a burst of low energy gamma-rays from the outer space lasting for a few seconds.

Tuesday, February 7, 2012

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Once or twice a day we see a burst of low energy gamma-rays from the outer space lasting for a few seconds.

Tuesday, February 7, 2012

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The energy released during a burst (~1051 erg within a few seconds) is only a few

  • rders of magnitude below the energy

released by the rest of the Universe at the same time! Once or twice a day we see a burst of low energy gamma-rays from the outer space lasting for a few seconds.

Tuesday, February 7, 2012

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The energy released during a burst (~1051 erg within a few seconds) is only a few

  • rders of magnitude below the energy

released by the rest of the Universe at the same time! Once or twice a day we see a burst of low energy gamma-rays from the outer space lasting for a few seconds. GRBs are the (electromagnetically) brightest

  • bjects in the Universe. Only ~8 orders of

magnitude less then the theoretically maximal * luminosity (c5/G)~1059 erg/sec .

* Up to relativistic corrections.

Tuesday, February 7, 2012

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Tuesday, February 7, 2012

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The Vela Satellites

The first burst

GRBs were discovered accidentally at the late 60ies by the Vela satellites, defense sattelites built to monitor the outer space treaty that forbade nuclear explosions in space. At that time - the late sixties - it was considered “impolite” to launch a spy sattelite.

Tuesday, February 7, 2012

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An invited prediction ?

Gamma ray Burst at shock break

  • ut from

Supernova explosion

Tuesday, February 7, 2012

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Shock breakout “first light”

An invited prediction ?

Gamma ray Burst at shock break

  • ut from

Supernova explosion

Tuesday, February 7, 2012

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Duration 0.01-1000s

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

1 burst in 2×107 years/galaxy

3 ×105 years/galaxy with beaming

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

1 burst in 2×107 years/galaxy

3 ×105 years/galaxy with beaming

~10keV – 10 MeV

  • (non thermal spectrum)
  • (very high energy tail,
  • up to GeV)

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

1 burst in 2×107 years/galaxy

3 ×105 years/galaxy with beaming

~10keV – 10 MeV

  • (non thermal spectrum)
  • (very high energy tail,
  • up to GeV)

Rapid variability

  • (less than 10ms)

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

1 burst in 2×107 years/galaxy

3 ×105 years/galaxy with beaming

~10keV – 10 MeV

  • (non thermal spectrum)
  • (very high energy tail,
  • up to GeV)

Rapid variability

  • (less than 10ms)

Typical energy ~1052 ergs

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

1 burst in 2×107 years/galaxy

3 ×105 years/galaxy with beaming

~10keV – 10 MeV

  • (non thermal spectrum)
  • (very high energy tail,
  • up to GeV)

Rapid variability

  • (less than 10ms)

Typical energy ~1052 ergs

Properties

Tuesday, February 7, 2012

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Duration 0.01-1000s

  • Two populations (long and short)

1 burst in 2×107 years/galaxy

3 ×105 years/galaxy with beaming

~10keV – 10 MeV

  • (non thermal spectrum)
  • (very high energy tail,
  • up to GeV)

Rapid variability

  • (less than 10ms)

Typical energy ~1052 ergs

Followed by multiwavelength Afteglow

Properties

Tuesday, February 7, 2012

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The ultimate multimessangers

γ-rays: up to 33 GeV X-rays: 0.1kev - 100 kev uv

  • ptical

IR Radio UHE neutrinos Gravitaiotnal Radiation UHECRs?

Tuesday, February 7, 2012

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The ultimate multimessangers

γ-rays: up to 33 GeV X-rays: 0.1kev - 100 kev uv

  • ptical

IR Radio UHE neutrinos Gravitaiotnal Radiation UHECRs?

Tuesday, February 7, 2012

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The ultimate multimessangers

γ-rays: up to 33 GeV X-rays: 0.1kev - 100 kev uv

  • ptical

IR Radio UHE neutrinos Gravitaiotnal Radiation UHECRs?

?

Tuesday, February 7, 2012

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The ultimate multimessangers

γ-rays: up to 33 GeV X-rays: 0.1kev - 100 kev uv

  • ptical

IR Radio UHE neutrinos Gravitaiotnal Radiation UHECRs?

?

Tuesday, February 7, 2012

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The Bahcall Symposium (1995): Some Open Question in Atrsonomy

Where? What? How? Why?

Tuesday, February 7, 2012

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Where ?

Cosmological

Galactic

Tuesday, February 7, 2012

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High redshift GRBs

GRB 090423 at a redshift 8.26 is the most distant object seen so far*. At that time the Universe was 640 million years

  • ld, or less than 5 percent of

its present age.

* two other GRBs with claimed but unconfirmed yet higher redshift (9.4 and > 10)

  • N. Tanvir, 2006

Tuesday, February 7, 2012

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High redshift GRBs

GRB 090423 at a redshift 8.26 is the most distant object seen so far*. At that time the Universe was 640 million years

  • ld, or less than 5 percent of

its present age.

* two other GRBs with claimed but unconfirmed yet higher redshift (9.4 and > 10)

  • N. Tanvir, 2006

Tuesday, February 7, 2012

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What ?

Tuesday, February 7, 2012

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Energy, Energy, Energy + Time

E ≈ 1051-1052 ergs ≈ the binding energy of a compact stellar mass object. 0.01-100 sec + E ≈ 1051-1052 ergs ⇒ a newborn stellar mass compact object. ⇒ Collapsing stars or mergers of compact

  • bjects

Tuesday, February 7, 2012

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Different routes can lead to a Black-hole - disk-jet system:

  • NS/BH-NS merger
  • BH-WD merger
  • NS/BH-He core merger
  • Collapsar

short Long

Tuesday, February 7, 2012

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Different routes can lead to a Black-hole - disk-jet system:

  • NS/BH-NS merger
  • BH-WD merger
  • NS/BH-He core merger
  • Collapsar

short Long

  • LONG
  • SHORT

Tuesday, February 7, 2012

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Neutron star mergers as progenitors of short GRBs (Eichler Livio, TP, Schramm, 1988)

Magnetic field jet arising from NS merger Rezolla et al., 2011 NS merger simulations Price & Rosswog 2007

Tuesday, February 7, 2012

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Price & Rosswog

Tuesday, February 7, 2012

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Price & Rosswog

Tuesday, February 7, 2012

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Price & Rosswog

Tuesday, February 7, 2012

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Short GRBs – GRB 050509b

Swift/XRT position intersects a bright elliptical at z = 0.226 No optical/radio afterglow

Bloom et al. 2005 Castro-Tirado et al. 2005 Gehrels et al. 2005 Hjorth et al. 2005

Elliptical host ⇓ Old stellar population

Kulkarni et al. 2005

Tuesday, February 7, 2012

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The (long) GRB-Supernova connection

Tuesday, February 7, 2012

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The (long) GRB-Supernova connection

  • Observational indications
  • Long GRBs arise in

star forming regions (Paczynski 1997)

Tuesday, February 7, 2012

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The Smoking Gun

GRB030329-SN 2003dh - a regular GRB with a 98bw like supernova.

  • Tuesday, February 7, 2012
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The Smoking Gun

GRB030329-SN 2003dh - a regular GRB with a 98bw like supernova.

  • Tuesday, February 7, 2012
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The Smoking Gun

GRB030329-SN 2003dh - a regular GRB with a 98bw like supernova.

  • Recently we have also GRB101219B - SN 2010ma

Tuesday, February 7, 2012

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Route to GRBs

Tuesday, February 7, 2012

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How ? Enigma

Tuesday, February 7, 2012

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Variability δt=0.1sec ⇓ R<c δt=3×109cm 1051 erg e+e- e-e+ e+e- e+e- e+e- γγ -> e+e−

τ~1015

The Compactness problem

One should expect a thermal

  • spectrum. BUT

Tuesday, February 7, 2012

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Relativsitic Motion

  • R ≤ Γ2cδΤ
  • Eph (obs) = ΓEph (emitted)
  • τγγ = Γ−(2+2α) nγσΤ R ≈ 1015/Γ(2+2α)

Tuesday, February 7, 2012

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Relativsitic Motion

  • R ≤ Γ2cδΤ
  • Eph (obs) = ΓEph (emitted)
  • τγγ = Γ−(2+2α) nγσΤ R ≈ 1015/Γ(2+2α)

τ<1 → Γ>100

Tuesday, February 7, 2012

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13

Confirmation of Relativistic Motion

Piran - VSOP 2011 Hue Vietman

Tuesday, February 7, 2012

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13

Confirmation of Relativistic Motion

GRB 970508 R=1017cm t=1 month

Frail et al., 97

Piran - VSOP 2011 Hue Vietman

Tuesday, February 7, 2012

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13

Confirmation of Relativistic Motion

GRB 030329 R=1018 cm t=100 days

Taylor et al., 04 Oren, Nakar, TP, 04

Piran - VSOP 2011 Hue Vietman

Tuesday, February 7, 2012

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Relativistic Jets

Some bursts show an “isotropic equivalent” energy of >1054 ergs. This is more than a solar rest mass

  • > The emission must be beamed

Tuesday, February 7, 2012

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Relativistic Jets

Some bursts show an “isotropic equivalent” energy of >1054 ergs. This is more than a solar rest mass

  • > The emission must be beamed

Tuesday, February 7, 2012

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Internal External Shocks

Tuesday, February 7, 2012

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Relativistic Outflow

Internal External Shocks

Inner Engine 106cm

Tuesday, February 7, 2012

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Relativistic Outflow

Internal External Shocks

Inner Engine 106cm

Tuesday, February 7, 2012

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Relativistic Outflow

Internal External Shocks

Internal Shocks γ-rays 1013-1015cm Inner Engine 106cm

Tuesday, February 7, 2012

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Relativistic Outflow

Internal External Shocks

Internal Shocks γ-rays 1013-1015cm Inner Engine 106cm

Tuesday, February 7, 2012

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Relativistic Outflow

Internal External Shocks

Internal Shocks γ-rays 1013-1015cm Inner Engine 106cm

Tuesday, February 7, 2012

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Relativistic Outflow

Internal External Shocks

Internal Shocks γ-rays 1013-1015cm Inner Engine 106cm External Shock Afterglow 1016-1018cm

Tuesday, February 7, 2012

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Short lived accretion disk

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Duration ~30 sec – accretion time scale. Variability ≤ 0.1 sec – fluctuation time scale.

Tuesday, February 7, 2012

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BUT - Numerous open questions

Tuesday, February 7, 2012

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Relativistic Outflow

How is the jet generated?

Internal Shocks γ-rays 1013-1015cm Inner Engine 106cm External Shock Afterglow 1016-1018cm

Tuesday, February 7, 2012

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Blandford Znajek?

Uchida + 2001 Rezolla+ 2011

Tuesday, February 7, 2012

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Relativistic Wind

Baryonic

Inner Engine e e e p p p

Jet Composition?

Tuesday, February 7, 2012

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Relativistic Wind Inner Engine

  • r Poynting Flux

~1016G

Jet Composition?

Tuesday, February 7, 2012

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Relativistic Outflow

What is the emission process?

Internal Shocks γ-rays 1013-1015cm Inner Engine 106cm External Shock Afterglow 1016-1018cm

Tuesday, February 7, 2012

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The Collapsar Model

(MacFadyen & Woosley 1998)

Tuesday, February 7, 2012

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The Collapsar Model

(MacFadyen & Woosley 1998)

Tuesday, February 7, 2012

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The Jet drills a hole in the star Model

Zhang, Woosley & MacFadyen 2004

Tuesday, February 7, 2012

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Jet Simulations (Obergaulinger, Piran + 11)

Opening angle of 15o degrees at 2000 km into a star of 15 solar masses and solar

  • metallicity. Constant

energy injection rate, 5 * 1050erg /s, through the entire run of the

  • model. Lorentz factor at

injection 7

Tuesday, February 7, 2012

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Jet Simulations (Obergaulinger, Piran + 11)

Opening angle of 15o degrees at 2000 km into a star of 15 solar masses and solar

  • metallicity. Constant

energy injection rate, 5 * 1050erg /s, through the entire run of the

  • model. Lorentz factor at

injection 7

Tuesday, February 7, 2012

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98bw

llGRBs

TB

Tuesday, February 7, 2012

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Low luminosity GRBs - llGRBs

don’ t arise from Collapsars

98bw

llGRBs

TB

Tuesday, February 7, 2012

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Low Luminosity GRBs - llGRBs

Bromberg Nakar, TP, 11 ApJL 2011

  • Low luminosity GRBs:
  • Eiso~1048-1049 ergs
  • Smooth single peaked light

curve.

  • Soft Emission (Epeak <150 keV)
  • Much more numerous than

regular long GRBs!

  • llGRBs dont have enoug

power to penetrate the star

SN Ib/c Long Short llGRBs

Wanderman & Piran Energy Rate time counts

Tuesday, February 7, 2012

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Jet Simulations - A Failed Jet (Obergaulinger, Piran + 11)

Opening angle of 15o degrees at 2000 km into a star of 15 solar masses and solar metallicity. Constant energy injection rate, 5*1050erg/s, for 2 seconds.

Tuesday, February 7, 2012

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What makes a llGRBs?

Tuesday, February 7, 2012

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What makes a llGRBs?

A weak jet that fails to break out (“a failed GRB”).

Tuesday, February 7, 2012

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What makes a llGRBs?

A weak jet that fails to break out (“a failed GRB”). We observe the shock breakout form the stellar envelope (Colgate, 1967; Katz, Budnik, Waxman, 2010; Nakar & Sari, 2011)

Tuesday, February 7, 2012

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Three types of GRBs

Collapsars - collapse of a massive star - generation of a jet that penetrates the envlope and produces γ- rays at a large distance Mergers - mergers of two neutron stars produce short GRBs

low luminosity GRBs - produced by a

shock breakout from a supernova.

Tuesday, February 7, 2012

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Why ? A Tool

Tuesday, February 7, 2012

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Standard Candles for cosmological parameters?

But GRBs are NOT standard candles*

★The GRBs’Philips relation was not discovered yet

(see however Amadi relations and Yonetoko relations).

Tuesday, February 7, 2012

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Measure the Cosmic Star fromation rate?

SFR (Bouwens+10) GRBs (Wanderman & TP 10)

Tuesday, February 7, 2012

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Laboratory for Extreme Conditions near Black Holes

F . Mirabel

Extreme gravitational fields Huge magnetic fields Ultra-relativistic shocks Super Eddington accretion

Tuesday, February 7, 2012

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Laboratory for Extreme Conditions near Black Holes

F . Mirabel

Extreme gravitational fields Huge magnetic fields Ultra-relativistic shocks Super Eddington accretion

Tuesday, February 7, 2012

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Gravitational Radiation from Jet Acceleration

Tuesday, February 7, 2012

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Gravitational Radiation from Jet Acceleration

Tuesday, February 7, 2012

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Gravitational Radiation from Jet Acceleration

Nakamura minijet model

Tuesday, February 7, 2012

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GRBs are good for many things:

Tuesday, February 7, 2012

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GRBs are good for many things:

Determining the high redshift history of the universe ?

Tuesday, February 7, 2012

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GRBs are good for many things:

Determining the high redshift history of the universe ?

Tuesday, February 7, 2012

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GRBs are good for many things:

Determining the high redshift history of the universe ?

Tuesday, February 7, 2012

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GRBs are good for many things:

Determining the high redshift history of the universe ?

Tuesday, February 7, 2012

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GRBs are good for many things:

Determining the high redshift history of the universe ? Source of Ultra High Energy Cosmic Rays?

Tuesday, February 7, 2012

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GRBs are good for many things:

bad

Determining the high redshift history of the universe ? Source of Ultra High Energy Cosmic Rays? Destroy Life on Earth (mass extinction) ??

Tuesday, February 7, 2012

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GRBs are good for many things:

Determining the high redshift history of the universe ? Source of Ultra High Energy Cosmic Rays? Destroy Life on Earth (mass extinction) ?? Creat Life on Earth (trigger planet formation)?

Tuesday, February 7, 2012

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GRBs are good for many things:

Determining the high redshift history of the universe ? Source of Ultra High Energy Cosmic Rays? Destroy Life on Earth (mass extinction) ?? Creat Life on Earth (trigger planet formation)? Measuring quantum gravity effects

Tuesday, February 7, 2012

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γ1 γ2

Lorentz Invariance Violation and GRB (Amelino-

Camelia et al., 1998)

Tuesday, February 7, 2012

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γ1 γ2

Lorentz Invariance Violation and GRB (Amelino-

Camelia et al., 1998)

Tuesday, February 7, 2012

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Tuesday, February 7, 2012

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Fermi’s

  • bservations of

GRB090510

dt35MeV-31GeV < 0.1 sec ⇒ ξ (1) > 1.2 ⇒ E(1)LiV > 1.4 1019 GeV

Tuesday, February 7, 2012

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ξ(2)=10-12 ξ(2)=10-7 ξ(2)=10-2 ξ(1)=0.01 ξ(1)=1 106 108 1010 1012 1014 1016 1018E/eV 10-6 106 0.001 1 1000 Δt (sec) GRB 090510 ξ(1,2)=ELiV/Mpl GRB neutrinos

High Energy GRB photons

GRB photons

Tuesday, February 7, 2012

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ξ(2)=10-12 ξ(2)=10-7 ξ(2)=10-2 ξ(1)=0.01 ξ(1)=1 106 108 1010 1012 1014 1016 1018E/eV 10-6 106 0.001 1 1000 Δt (sec) GRB 090510 ξ(1,2)=ELiV/Mpl GRB neutrinos

High Energy GRB photons

GRB photons

Tuesday, February 7, 2012

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Summary

GRBs are the brightest explosions in our Universe GRBs hearlds the formation of a compact object - most likely a black hole Long GRBs = Collapsars, Short GRBs ≈ Mergers

low luminosity GRBs (≠ Collapsar) ≈ shock break out

GRBs are the best natural laboratories to study physics under extreme conditions The Bright GRB explosion and their afterglow can serves as a tool to explore the early Universe Might be sources of UHECRs, UHE neutrinos and GW

Tuesday, February 7, 2012