Giant Radio Pulses Radio Properties Mechanism High Energy

Giant Radio Pulses Radio Properties Mechanism High Energy Properties With Astrosat & LOFT

Giant Radio Pulses Crab • Flux density > M Jy Tb > 1037 K! • Highly variable polarisation • Scales ~ 1 m

Giant Radio Pulses Crab Giant pulses in different Radio frequencies are simultaneous GPs occur only at the normal pulse Phases MP and IP Mickaliger et al. 2012

Giant Radio Pulses First observed in the Crab pulsar - discovered through its giant pulses! • Intense narrow pulses (~10 ns) • Brightness Temp: upto 5 x 10^39 • Random in occurrence, at certain pulse phases • Pulse energy many times that of an average pulse • One or more power-law distribution of pulse energies • Highly polarizeded/variable

Giant Radio Pulses Crab Popov et al. 2007 Karuppusamy et al. 2010

Giant Radio Pulses Crab Pulse width up to 100 s 50 -90% of total pulse Flux energy is in the Giant pulses Majid et al. 2011

Giant Radio Pulses PSR B 1937+21 Kinkhabwala et al. 2000

Giant Radio Pulses PSR B 1937+21 Kinkhabwala et al. 2000

Giant Radio Pulses PSR B 1937+21 Soglasnov et al. 2004 Width: < 15 ns T_B : 5 x 10^39 K Discharges in the polar cap region

Giant Radio Pulse: Mechanism • Conversion of electrostatic turbulence in the pulsar magnetosphere by the mechanism of spatial collapse of nonlinear wave packets (Hankins et al. , 2003) • Electric discharge due to the magnetic reconnection of field lines connecting the opposite magnetic poles (Istmin Ya. N. , 2004) • Coherent curvature radiation of charged relativistic solitons associated with sparking discharge of the inner gap potential drop above the polar cap (Gil, J & Melikadze G. , 2004) • Induced Compton scattering of pulsar radiation off the particles of the plasma flow (Petrova S. A. 2004) • Cyclotron line at the light cylinder during reconnection events (Lyutikov 2013)

Giant Pulses from MSPs • Large magnetic field at the light cylinder • Pulsed non-thermal X-ray emission • X-ray emission at the same phase of GP PSR J 0218+4232 PSR B 1937+21 RXTE GBT 850 MHz Beppo. SAX Chandra 0. 1 -10 kev Radio (Knight et al. 2006) (Cusumano et al. 2003)

Giant Pulses and High Energy emission: Crab • Optical • Flux enhancement: 3% • Enhancement of electron positron plasma (Shearer et al. 2003)

Giant Pulses and High Energy emission: Crab • Optical • Peak flux enhancement: 11% for Giant Pulses near the peak of the optical pulse, 3% otherwise • Flux enhancement: 3% for Giant Pulses at the Main Pulse (Strader et al. 2013)

Giant Pulses and High Energy emission: Crab • Chandra HRC: 1. 5 - 4. 5 ke. V (Bilous et al. 2012) • Chandra HCR: 1. 5 - 4. 5 ke. V • Upper limit of flux enhancement in pulses with GPs: 10% for MP GPs and 30% for IP GPs • Upper limit of flux enhancement during the GPs: 2 for MP GPs and 5 for IP GPs • Due to changes in coherent radio emissiom

Giant Pulses and High Energy emission: Crab • Suzaku HXD, 15 -75 ke. V and 35 -315 ke. V • 1 σ upper limit of flux enhancement: 70% (Mikami et al. 2014)

Giant Pulses and High Energy emission: Crab • Fermi: 100 Me. V - 5 Ge. V • 95% confidence upper limit of flux enhancement: 4 times for all GPs and 12 for IP GPs • Due to changes in coherent radio emissiom and not due to enhanced particle density (Bilous et al. 2011)

Giant Pulses and High Energy emission: Crab • Veritas: > 150 Ge. V • Upper limit of flux enhancement: 5 times for pulses with GP • Upper limit of flux enhancement: 2 times for 8 s window around GP Aliu et al. 2012

Giant Pulses and High Energy emission: 1937+21 • X-ray emission is at the same phase as the Giant Pulses Cusumano et al. 2003, Nicastro et al. 2004

Giant Pulses and High Energy emission • S/N = s. A*T/sqrt((s. A+b. A)T)= sqrt(AT)*s/sqrt(s+b) RXTE-PCA/ASTROSAT-LAXPC s Chandra T Crab: 10 hrs 10000 bursts 0. 2 sec, 400 photons, à 100 photons (5 sigma) sensitivity of 0. 01 photon per GP à 10^33 erg per GP in X-rays

Stability of X-ray Pulse Profiles: Crab Jain and Paul 2011 ISRO HQ - 22 Apr 2014