Bez tytulu slajdu

1

Pulsar studies in the high energy domain
Bronek Rudak
(CAMK) Jarek Dyks (CAMK) Michal
Frackowiak Gottfried Kanbach (MPE) Aga
Slowikowska (U. of Crete)
, X-ray binaries, accretion disks and compact
objects Oct 7 - 13, 2007

2

• - What do we know about high energy radiation
  from pulsars?
• How do the observations constrain pulsar models?
• Why we need GLAST, H.E.S.S.II and POGOLite ?
• For the purpose of this
  talk
• high energy optical,
  UV, X-rays, gamma rays
• with emphasis on gamma
  rays

3
The ATNF Pulsar Database 1770 objects
4
Why do pulsars radiate in high energy?

• 1) Pulsars are rotating, strongly
• magnetized neutron stars
• they can act as unipolar inductors
• 2) The maximum potential drop can reach
• Vmax ? 7 ? 1012 B12 P-2 Volts,
• i.e. for young pulsars Vmax can exceed 1016
  Volts.
• 3) This potential drop can accelerate charged
  particles to ultrarelativistic energies
• emitting high energy photons.
• Important
• The size and shape of the accelerators (the
  gaps) is model dependent.

5
Pulsars across electromagnetic spectrumlight
curves and spectra
D.J. Thompson 2003
6
Vela pulsar
Harding et al., 2001
7
D.J. Thompson 2003
8
H.E.S.S. results (F. Schmidt et al., 2005)
9
Venter de Jager 2004
10
Radiative processes in strong magnetic field 1.
Curvature radiation 2. Inverse Compton
Scattering (resonant non-resonant) 3. Magnetic
pair creation ( 1? ? e ) 4.
Photon-photon pair creation ( 2? ? e ) 5.
Synchrotron radiation 6. Photon splitting ( 1?
? 2? )

11
Examples of models of phase-averaged energy
spectrum of B0833-45 (Vela)
12
Fig. by A.K. Harding
13
Two-pole caustic slot gap model
Dyks R. 2003
outward emission along last open field lines
inward emission along last open field lines
14
Two-pole caustic model and outer gap
modelvs.Vela
15
Polarimetry of the Crab pulsar - Slowikowska et
al. 2006 (OPTIMA)
Polarization Degree
Position Angle
DC ? 2 of MP p ? 33, ? ? 119º
16
Light curves and polarisation characteristics
within the framework of three high energy
magnetospheric emission models of pulsars
Dyks et al. 2004
17

• T. Kamae et al.2007
• The Polarised Gamma-ray Observer
• Lightweight Version
• POGOLite
• a baloon-borne polarimeter
• Energy range 25 80 keV
• First flight in 2009

18
Kamae et al. 2007

Main pulse of the Crab pulsar by three
models with 6 hour of simulated observations by
POGOLite
19
What about pulsars which dont have slot gaps?
Harding, Muslimov Zhang 2002
20
Taken from S. Ritz (2007)
21
W. Hofmann (2007)
22
W. Hofmann (2007)
23
Rotation leads to non-axisymmetric magnetic
absorption
24
For GLAST
P 0.1s
25
Peak-to-peak separation changes w. energy in
presence of magnetic absorption
For GLAST
26
VELA - polar cap model 1
super-exponential cutoff in the spectrum
For GLAST
27
VELA - polar cap model 2 BUT
exponential cutoff in the spectrum !
For GLAST
28
HE spectra of millisecond pulsars
Kuiper Hermsen 2003
29
PSR J02184232 the first millisecond pulsar in
gamma-rays
P 2.32 ms Bpc 0.001 TG d 5.85 kpc

BeppoSAX points - Mineo et al.. 2000 EGRET points
- Kuiper et al.. 2000
30
Simple polar gap model for gamma rays
in millisecond pulsars
Example P 2.3 ms B 0.001 TG inclination a
60
31
Two models of J0437-4715 photon maps and
light curves above 100 MeV
For GLAST
? 35?, ? 40?
? 20?, ? 16?
32
A model of B1821-24 P 3.1 ms, B
0.002 TG, d 5.1 kpc
? 50o z 45o
For GLAST
photon flux above 100 GeV
For H.E.S.S. II
33
Model of J02184232 w. mini-caustics (slot
gaps), ? 25?, ? 47?
34

H.E.S.S.