UHECRs & GRBs
Eli WaxmanWeizmann Institute, ISRAEL
The acceleration challenge
RB eBRBR
R
BR
ccV p
v/
1~
1 2
ce
BRL p
222
2
1v
84
v
v
erg/s102 45220,
2
pL
2R
tRF=R/c)
l =R/
2 2
[Hillas, ARA&A (1984); Waxman 04]
The suspects
• Active Galactic Nuclei (steady):
~ few requires L>1047 erg/s Few, brightest AGN
• Gamma Ray Bursts (transient):
~ 300 requires L>1051 erg/s Average L~1052 erg/s
The Suspects
losses
1/[Hillas 84; Arisaka 02]
Comments on “Magnetars”
• Newborn Neutron stars (Hypothesis) with: B~1014G, ~104/sec LEM~1050 erg/s for t<1 min.
• Some difficulties:
Wind should penetrate
envelope with <10-12 Msun entrainment
Acceleration mechanism: Unknown
NS
~1 Msun envelope
EM wind
[e.g. Blasi, Epstein, Olinto 00; Arons 02]
[Waxman 04]
Gamma-ray Bursts
M on ~1 Solar Mass BH
Relativistic Outflowe- acceleration in
Collisionless shocks
MeV ’s: L~1052erg/s
~300
[Piran, Phys. Rep. 99; Meszaros, ARA&A 02 ;Waxman, Lec. Notes Phys. 598 (2003)].
e- SynchrotronX-ray, UV Radio
UHE p Acceleration
Proton/electron acceleration: ‘95
Protons• Acceleration/expansion:
• Synchrotron losses:
• Particle spectrum:
• p energy production:
Electrons• MeV ’s:
• Optical depth:
spectrum:
energy production
125.2
220, 51,
2.0/
Luu peB 1.0/ eB uu
4/12
4/320,
210 tp
5.210
2/ eee ddn 2/ ppp ddn
yrMpc
erg10
3442
p
pp d
nd
yrMpc
erg10erg10
yrGpc
10~
34452
32
e
ee d
nd
[Waxman 95, PRL 75, 386; ApJ 452, L1; Note: Constraints independent of details of acceleratiomn model (e.g. Gialis & Pelletier 04)]
1997: BeppoSAX (GRB afterglows)
• Detection of (predicted) X-ray, Optical & Radio “afterglow”
• Identification of “host” galaxies, <z>~2
• Detailed tests of the model Size measurements [scintillation, VLBI, sub-rel.]
X-ray to radio (synchrotron) spectra
[e.g. Meszaros, ARA&A 02]
[Waxman, Kulkarni & Frail 98; Taylor, Frail, Berger & Kulkarni 04 ;Frail, Waxman & Kulkarni 00; Berger, Kulkarni & Frail04]
[e.g. 970508, Wijers & Galama 98]
Afterglow: UHECR implications
• L=1051 erg/s -> L=1052 erg/s
• Early optical afterglow: uB/ue~1,
~102.5
• Revised rates, energy 10/Gpc3yr -> 0.5/Gpc3yr E=1052 erg -> E=1053.5 erg
[Zhang,Kobayashi, Meszaros 03; Soderberg, Ramirez-Ruiz 03]
[Schmidt 01; Guetta, Piran, Waxman 03]
Proton/electron acceleration
Protons• Acceleration/expansion:
• Synchrotron losses:
• Particle spectrum:
• p energy production:
Electrons• MeV ’s:
• Optical depth:
spectrum:
energy production
125.2
220, 51,
2.0/
Luu peB1.0/ eB uu
4/12
4/320,
210 tp
5.210
2/ eee ddn 2/ ppp ddn
yrMpc
erg10
3442
p
pp d
nd
yrMpc
erg10erg10
yrGpc
10~
34452
32
e
ee d
nd
[Waxman 04]
1~/ eB uu
5.210
yrMpc
erg10erg10
yrGpc
5.03
445.533
[Waxman 95]
Afterglow
0.0252
UHECR generation
• Galactic heavy nuclei X-Galactic protons
• X-Galactic protons Generation spectrum & rate (z evolution follows SFR):
• <1019eV Galactic heavy nuclei Fly’s Eye fit: JG~E-3.50
[Waxman 95; Bahcall & Waxman 03]
yrMpc
erg1065.0
3442
p
pp d
nd
[Watson 91, Nagano & Watson 00]
~1019eV
Model vs. Data
[Bahcall & Waxman 03]
Ruled out at 5
“GZK sphere”• AGN, Radio-galaxies • GRBs :
• For RGRB(z=0)~0.5/Gpc3yr
• Prediction:
p
yrMpcG10
Mpc100/10~~
28
22
20
7
BDelaySpread
BD
D
B
MpcG10
Mpc)100/(102~)(
28
2
2
54
20
BGRBs
BDN
few~)eV103( 20GRBsN
[Waxman 95; Miralda-Escude & Waxman 96, Waxman 03]
GRB Model Predictions
• >3x1020eV: Few, narrow spectrum
sources; Fluctuations (no
homogeneous GZK).
• Auger
• AGASA multiplets- statistical significance?
[Miralda-Escude & Waxman 96][Teshima 03;
Finley & Westerhoff 04]
[Watson 91, Cronin 93]
“Generic” GRB ’s•
•
• Weak dependence on model parameters
2GeV3.0//
;
p
eenp
eV10,eV1010,MeV1 5.14165.2 p
yrkm/20
eV10,srscm
GeV10
2
5.142
82
J
2.0pf
[Waxman & Bahcall 97, 99; Rachen & Meszaros 98; Alvarez-Muniz & F. Halzen 99; Guetta, Spada & Waxman 01; Guetta, Hooper, Alvarez-Muniz, Halzen & E. Reuveni 04]
Summary• GRBs >1019eV protons (acceleration, rate) Predictions 103km2 area detectors experiments: HiRes, Auger, T.A., EUSO/OWL
• GRBs 100TeV ’s Flux 1Gton detectors Experiments: Baikal, AMANDA IceCube, Antares, Nestor, NEMO
• detectionGRBs: CR puzzle, GRB progenitors & physics
physics: appearance
Lorentz Inv. (10-16), Weak equivalence principle (10-6)
Direct size measurement: Scintillation
• Finite size, cosmological source: hcrit.~few x 1017cm
ne
d
d >
Diffractive scintillation
h
[Frail, Waxman & Kulkarni 00]
cm1022
8/5week
8/1
0
5317obs t
n
Ect
Rh
“Cannon balls”• Proper motion: D&D 2003: >1.4 mas for 030329 Obs.: 0.1+-0.1
• Inconsistent with scintillation suppression
33 10~,10~
CBpCB Rcn 104-37 10~cm10~/,cm10~
[ Dado, Dar & De Rujula 02]
