# Presentation: 611435

## Astrophysical Solution to the Problem of UHECR Origin: Gamma-Ray Bursts Chuck Dermer (US Naval Research Laboratory)PANIC (Particles and Nuclei International Conference)Santa Fe, NM, 27 October 2005dermer@gamma.nrl.navy.mil Armen Atoyan (UdeM)  Jeremy Holmes (TJHSST, NRL, FIT) Stuart Wick (NRL, SMU) 

**Astrophysical Solution to the Problem of ****UHECR Origin: Gamma-Ray Bursts** **Chuck Dermer**** ****(US Naval Research Laboratory)****PANIC (Particles and Nuclei International Conference)****Santa Fe, NM, 27 October 2005****dermer@gamma.nrl.navy.mil**** ****Armen Atoyan**** ****(UdeM)**** **** ****Jeremy Holmes**** ****(TJHSST, NRL, FIT)**** ****Stuart Wick**** ****(NRL, SMU)**** **

**Astrophysical Evidence: UHECRs and GRBs**
**Origin of Cosmic Rays: A Complete Model**
**High-Energy Neutrinos from GRBs: Test of GRB/Cosmic Ray model**
**Cosmic Rays from GRBs in the Galaxy**
** **

## Astrophysical Evidence for GRB Origin of Cosmic Rays

**Astrophysical Evidence for GRB Origin of Cosmic Rays**

## Predicted cutoff above 1020 eV due to p +    0,+ interactions with Cosmic Microwave Background radiation

**Ultra-High Energy Cosmic Rays**

**Extragalactic Origin:**
**(1) GZK cutoff**
**(2) Pair production dip**
**(3) Heavy-to-light transition at second knee**

- 	(Greisen, Zatsepin, Kuzmin, or GZK effect)
- AGASA observations show no cutoff (disagrees with HiRes observations)
- New Auger results

**Notes:**
r_L = 10 kpc for 1e19 eV proton and 1 muG field

## High Energy Delayed Emission from GRB 940217 

**High Energy Delayed Emission from GRB 940217 **

- (Requires low-redshift GRB to avoid attenuation by diffuse IR background)

- Nonthermal Particle Acceleration in GRBs to multi-GeV energies
- Delayed second component in emission spectrum

- (Hurley et al. 1994)

## GRB 970417a TeV Detection with Milagrito 

**GRB 970417a TeV Detection with Milagrito **

- (Requires low-redshift GRB to avoid attenuation by diffuse IR background)

- Other evidence for high-energy radiation from GRBs:
- Seven GRBs detected with EGRET either during prompt sub-MeV burst emission or after sub-MeV emission has decayed away (Dingus et al. 1998)
- Average spectrum of 4 GRBs detected over 200 s time interval from start of BATSE emission with photon index 1.95(0.25) (> 30 MeV)

- (Atkins et al. 2002)

## Evidence for Cosmic Rays in GRB 941017

**Evidence for Cosmic Rays in GRB 941017**

- Anomalous -ray component seen in 2 other GRBs

- González et al., Nature (2003)

- t90 = 77 s

- GRB 941017 Light Curves

- t90 = 200 s

## 2. Complete Solution to the Problem of CR Origin

- Cosmic Rays below ≈ 1014 eV from SNe that collapse to neutron stars
- Cosmic Rays above ≈ 1014 eV from SNe that collapse to black holes
- CRs between knee and ankle/second knee from GRBs in Galaxy
- CRs at higher energy from extragalactic/ cosmological origin
- Power-law transition at second knee
- Diversity of SN types

- (Wick et al. 2004)

## Energy-loss Mean Free Path of UHECR Protons on CMBR Photons

- Energy Losses
-  Photopair
-  Photopion
-  Expansion

- z = 0

## Production of the ankle in 

- Assume luminosity density of GRBs
- follows SFR history of Universe

**Production of the ankle in **
**extragalactic CR spectrum**

- Ankle due to pair-production losses on CMBR
- (Berezinskii et al 2002)

- LSFR

- USFR

## Best Fit to High Energy Cosmic Ray Data

- Inject -2.2 spectrum (relativistic shock acceleration index)
- Better fit with upper SFR
- “Second knee” at transition between galactic and extragalactic components
- Fits to KASCADE and HiRes data imply local luminosity density of GRBs
-       Requires large baryon    	load:  fb ~ 50-200

## Fits to AGASA Data

- Fit highest energy points with hard injection spectrum
- Requires other sources for lower energy cosmic rays

- GRB model implies AGASA results not valid
- If correct, points to new physics
- Will be resolved with Auger

## Injected CR energy: 1052 ergs at 1 kpc

**CR flux evolution from a local GRB: *****simple power-low D(E)***

- Injected CR energy: 1052 ergs at 1 kpc
- 	Emax=1021 erg,  = 2.2
- D(1 PeV)= 1029 cm2 s-1,  =0.6
- Galactic halo size: 10 kpc

- (conserves the number
- of particles in *r**dif*3)

## 	Cosmic rays diffuse through stochastic gyro-resonant pitch-angle scattering with MHD wave turbulence.

- Larmor
- Radius:
- Mean free path  for deflection by /2:

**Diffusion of Cosmic Rays due to plasma turbulence**

- 	Cosmic rays diffuse through stochastic gyro-resonant pitch-angle scattering with MHD wave turbulence.

- Turbulence injection scales:
**~1pc** (***SNR***) & **~100pc** (***G. disc***)

- Wick, Dermer, & Atoyan (2004)

## CR flux evolution from a local GRB: model diffusion coefficient

**CR flux evolution from a local GRB: ***model diffusion coefficient*

## Fits to KASCADE data through the Knee

- GRB occurred ~2x105 years ago at a distance of ~500 pc  (Wick et al, 2004)
- (**similar for  t ~1 Myr, at r ~ 1 kpc; depends** on **D********t**)

## 3. Neutrinos from GRBs

**3. Neutrinos from GRBs**

**Standard Fireball/Blast**
**Wave Model**
- Leptonic emission processes:
-     1. Nonthermal synchrotron
-     2. Compton scattering
- Hadronic emission processes:
-    1. Photopion production
-    2. Cascade radiation

## Proton Injection and Cooling Spectra

- Escaping neutron
- distribution

- Injected proton
- distribution

- Cooled proton
- distribution

**Nonthermal Baryon Loading Factor f****b**** = 30**

- GRB synchrotron
- fluence

- Forms neutral beam of neutrons,  rays, and neutrinos

## Neutrino Detection from GRBs only with Large Baryon-Loading

- (~2/yr)

**Nonthermal Baryon Loading Factor f****b**** = 20**

## High Energy Emission from GRB Colliding Shells

**	****Very optically thick****	****to ******** attenuation in **
**	****TeV range**

- Razzaque, Kobayashi, & Mészáros (2004)

**unless ********  >~  1000**

- 1 TeV

## Neutral Beam Model for Anomalous -rays in GRB 941017

- Highly polarized nonthermal synchrotron radiation

**GRB jet**
**CR protons**

- 

- n

- 

- e-

- Escaping neutron beam forming hyper-relativistic electrons/positrons

**B**

- Neutral Beam Model (Atoyan and Dermer, ApJ, 2003) for blazar jets
- 	Two hadronic emission components

- Hadronic cascade radiation in jet

## Photomeson Cascade Radiation Fluxes

**Photomeson Cascade Radiation Fluxes**

- C2

- S2

- C3

- S1

- Total

**MeV**

- Photon index between −1.5
- and  −2
- Fits data for GRB 941017 spectrum during prompt phase
- Photomeson
- Cascade:

- Nonthermal Baryon Loading Factor fb = 1

-  = 100

-        emits synchrotron (S1)
- and Compton (C1) photons
-                 	    emits synchrotron (S2) and 	          	    Compton (C2) photons, etc.

- C1

- S4

- S5

- S3

- C4

- C5

- tot = 310-4 ergs cm-2

## Photon and Neutrino Fluence during Prompt Phase

**Photon and Neutrino Fluence during Prompt Phase**

- 	Hard -ray emission component from hadronic cascade radiation inside GRB blast wave with associated outflowing high-energy neutral  beam of neutrons, -rays, and neutrinos

- Nonthermal Baryon
- Loading Factor fb = 1

- tot = 310-4 ergs cm-2

-  = 100

## 5. Cosmic Rays from GRBs in the Galaxy

-  1 GRB every 10,000 – 100,000 years in the Milky Way (due to beaming)
- Fluence referred to Solar energy fluence in one second
- for significant effects on biology. Using constant-energy reservoir result implies

- 	where 105t5 yr is the mean time between galactic GRBs, and the GRB distance is

## Synchrotron and Compton Neutron-Decay Halos/ -ray Pair Halos

**Synchrotron and Compton Neutron-Decay Halos/ ********-ray Pair Halos**

- Neutrons formed through photomeson processes during cosmic ray acceleration escape from blast wave n p + e- + e
- Decay of ultrahigh energy neutrons occurs at  ~100 kpc
- Produce nonthermal synchrotron radiation, depending on strength of halo magnetic field
- Produce nonthermal rays from Compton scattering of CMB
-   rays materialize
- through  e+e-
- form extended pair
- and gamma-ray halo

- (Dermer 2002)

- (Aharonian, Coppi, and Völk 1994)

## Neutron Decay Emissions from a Galactic GRB

**Neutron Decay Emissions from a Galactic GRB**

- Compton-scattered CMBR from Neutron-Decay Electrons formed by GRB associated with W49B

- (Ioka, Kobayashi, & Mészáros 2004)

## 	GRB pointed towards Earth produced a lethal flux of high-energy photon and muons that destroyed the ozone layer, killed plankton, and led to trilobite extinction in the Ordovician Epoch (Melott et al. 2004)

**Biological Effects of Galactic GRBs**

- 	Geological evidence points toward two pulses; a prompt extinction and an extended ice age.
- 	Prompt neutrons and -rays from a GRB could have produced the  prompt extinction.  Delayed cosmic rays could have produced the later ice age

## Summary

- Complete model where Cosmic Rays originate from
- SNe that collapse to neutron stars in the Galaxy (E<~1014 eV),
- SNe that collapse to black holes (GRBs) in the Galaxy (1014 eV <~ E <~ 5x1017 eV),
- 3.   Extragalactic SNe that collapse to black holes (GRBs)  (E >~ 5x1017 eV)
- GRB/Cosmic Ray model requires that GRBs are hadronically dominated
- High-energy neutrino detection from GRBs only if GRBs are hadronically dominated
- Anomalous hard -ray emission component in GRB 941017 due to hadronic cascade radiation inside GRB blast wave (during prompt phase) and synchrotron radiation of hyper-relativistic electrons formed by outflowing neutrons (during prompt and extended phase)
- Observation of GRB 941017 may provide first clear evidence for hadronic acceleration in GRBs and the sites where high-energy cosmic rays originate
- GRBs in the Milky Way could have produced earlier extinction events
**Effects of cosmic ray irradiation on Earth not yet fully explored**

## Predictions

- Heavy to light transition at the second knee
- No multiplet events
- Ankle is due to pair production dip
- Display GZK cutoff, though must take into
- 		account enhanced GRB activity in local supercluster
- Neutrinos from GRBs (IceCube)
- Anomalous -ray emission components in GRBs
- 		correlated with neutrino activity
- 		(GLAST)
***UHECRs from blazars? ************-ray halos***

- Pictor A

- Cygnus A

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