GRB Puzzles The Baryon Purity Puzzle: Why is the energy spend on gamma rays and not on expanding matter? The photon entropy puzzle: Why Gamma Rays at 100 to 1000 KeV? Why not fewer photons at higher energy, or more photons at lower energy? Why is  what it is?

dM/dt scales as L 5/3+… (Duncan, Shapiro, and Wasserman 1986, Woosley and coworkers 1996)….. ….but nearly linearly with L e+e- (Levinson and Eichler 1993): Assume standing baryonic rarefaction wave at critical point: Then dM/dt = area x critical density x sound velocity ~ L 51 9/8 g/s TOO MUCH!

Possible answer to the Baryon Purity question: All or nothing principle: Something must prevent baryons from emerging. (e.g. event horizon, bare strange surface, NS gravity) This makes GRB particularly interesting. Perhaps they confirm Schwarzschild event horizons. Neutron stars, strange stars might not need accretion disk but black hole MUST have accretion disk, and accretion disk must generate a baryonic wind

CONSEQUENCE OF ALL OR NOTHING PRINCIPLE : ANY BARYONS IN GRB FIREBALL MUST HAVE ENTERED THROUGH THE SIDES e.g. from exterior baryonic wind, walls of host star…. They typically do so after the fireball is already at high  with violent consequences 

How? Why Gamma Rays at 100 to 1000 KeV? Possible answers: Neutron leakage Photon drag of walls

Why Gamma Rays at 100 to 1000 KeV? Possible Answers

Why Gamma Rays at 100 to 1000 KeV? Possible Answers Photosphere established by pair annihilation (Eichler and Levinson, 1999)

Neutron Leakage into Baryon-Pure Fireball Baryon pure jet Neutrons crossing B lines High  cm cm

Collisional Avalanche n n n n Neutrons converted to protons + neutrons + pairs + neutrinos. This happens quickly, near the walls. trigger Typical  p for emergent protons is about  2 # neutrons that diffuse across is of order (area/cross section)x(r/mfp) 1/2 roughly 10 50

Collisional Avalanche n n n n Neutron free streaming boundary N n about A/  Neutron and ex- neutron mist N n about A/  about A 12

1) Pure Compton drag of pick-up ex-neutron gives  = [( 3/4 )(L/L edd )(R s /R) +  o ] 1/3 (L/L edd ) about to 14, (Rs/R) about So  or order 10 2 to 10 8/3 So what is  ? 2) Gyration in Poynting flux gives naive estimate of [10 51 ergs/ N n mc 2 ] 1/2 ~300 but significant transverse gradients and subsequent acceleration

3) Constrained Compton drag of walls:  about or less than 1/sin , where  is the angular size of the photon production region as seen at the point of last scattering ….  of order 10 2 ? 

Thin pencil beam Hollow cone High polarization at   GRB Polarization by IC (Eichler and Levinson 2003) on the cone

Probability of observing polarization > P, homogeneous distribution, Euclidian geometry,

Compton Sailing WALL   s = 1 / sin  In frame of sail,  ’  /2 e,p

Intensity Polarization

Ring-shaped Source

The index k depends on details of detectability D D prop to k

Dependence on Source Geometry point source disk ring

Dependence on Beaming Factor Azimuthal overlap

Given geometry, dependence on  Compton sailing state

Polarization from scattering by geometrically THICK annulus

E iso - peak correlation (Amati et al 2002, Atteia et al 2003) E iso proportional to peak 2

Off-axis Viewing as Grand E iso - peak Correlate Viewer outside annulus Pencil beam  annulus

Inside annulus

1 MeV10 KeV GRB’sXRF’s

Reflection to Large Angles and GRB

dVmax/dcos  ( Eichler and Levinson, 1999 ) GRB type events can be normal GRB, but expected to be rarely observed, because of small Vmax, despite large solid angle.

Note that a)GRB did not have any significant flux above the pair production threshold. Scattered photons would not have pair produced with unscattered ones, even at large scattering angles b)Scattering material is at r>30 lightseconds, and probably propagated from source. It has an edge. Obscuration of scattered photons is not a necessary consequence of any assumptions of the model.

Distinguishing features of model: 1)Violent baryon loading allows extremely hard non-thermal spectra (even harder than shock acceleration). Multiscale baryon loading allows recycling of collisional byproducts, allowing extremely efficient UHE neutrino emission.

Distinguishing features of model: 1)Violent baryon loading allows extremely hard non-thermal spectra (even harder than shock acceleration). Multiscale baryon loading allows recycling of collisional byproducts, allowing extremely efficient UHE neutrino emission 2)Scattering off baryon-rich walls can account for GRB and similar ones as scattered photons into off-axis viewing angle

Distinguishing features of model: 1)Violent baryon loading allows extremely hard non-thermal spectra (even harder than shock acceleration). Multiscale baryon loading allows recycling of collisional byproducts, allowing extremely efficient UHE neutrino emission 2)Scattering off baryon-rich walls can account for GRB and similar ones as scattered photons into off-axis viewing angle 3) Positive polarization –intensity correlation expected if walls “sail” on Compton pressure. (Compton upscattering predicts negative correlation.)

Distinguishing features of model: 1)Violent baryon loading allows extremely hard non-thermal spectra (even harder than shock acceleration). Multiscale baryon loading allows recycling of collisional byproducts, allowing extremely efficient UHE neutrino emission 2)Scattering off baryon-rich walls can account for GRB and similar ones as scattered photons into off-axis viewing angle 3) Positive polarization –intensity correlation expected if walls “sail” on Compton pressure. (Compton upscattering predicts negative correlation.) 4)Annular geometry can account for X-ray flashes and Amati et. al E iso – peak correlation

5?) Matter kinetic energy significant only because of baryon seeding. Baryon seeding increases with GRB duration t 5/2. Afterglow efficiency may be an increasing function of duration. But we are not sure yet.