Light cylinder magnetic field vs. age Caraveo arXiv: 1009.2421 Total of 46 pulsars 29 of which detected in radio (further divided between 8 mPSRs and 21 “classical” pulsars) and 17 selected in gamma-rays (i.e. 16 discovered by LAT + Geminga)
Emission geometry D. Thomson, NASA/GSFC) From Encyclopedia article 'Gamma-ray astronomy'Gamma-ray astronomy gsfc.nasa.gov
Crab pulsar profile arXiv: 1007.2183 Gamma pulse is shifted relative to the radio pulse Now there are examples that radio and gamma pulses can be both: at nearly the same positions and significantly shifted. Gamma – OG, Radio – TPC?
Several models Polar cap (inner gap or space-charge limited flow) Outer gap Slot gap and TPC Striped wind
Population synthesis of gamma-ray PSRs (following Gonthier et al astro-ph/0312565) Ingredients 1.Geometry of radio and gamma beam 2.Period evolution 3.Magnetic field evolution 4.Initial spatial distribution 5.Initial velocity distribution 6.Radio and gamma spectra 7.Radio and gamma luminosity 8.Properties of gamma detectors 9.Radio surveys to compare with. Tasks 1.To test models 2.To make predictions for GLAST and AGILE
Beams 1. Radio beam 2. Gamma beam. Geometry of gamma-ray beam was adapted from the slot gap model (Muslimov, Harding 2003)
Other properties Pulsars are initially distributed in an exponential (in R and z) disc, following Paczynski (1990). Birthrate is 1.38 per century Velocity distribution from Arzoumanian, Chernoff and Cordes (2002). Dispersion measure is calculated with the new model by Cordes and Lazio Initial period distribution is taken to be flat from 0 to 150 ms. Magnetic field decays with the time scale 2.8 Myrs (note, that it can be mimicked by the evolution of the inclination angle between spin and magnetic axis). The code is run till the number of detected (artificially) pulsars is 10 times larger than the number of really detected objects. Results are compared with nine surveys (including PMBPS)
Drawbacks of the scenario Simplified initial spatial distribution (no spiral arms) Uncertainties in beaming at different energies Uncertainties and manipulations with luminosity Unknown correlations between parameters
New population synthesis Watters, Romani arXiv: 1009.5305 Outer gap model is prefered
Another one Takata et al. arXiv: 1010.5870 Outer gap
The first Fermi catalogue 56 pulsating sources out from 1451 sources in total arXiv: 1002.2280
Blind searches arXiv: 1007.2183 PSR J1957+5033 24 PSRs found in blind searches. See details in arXiv: 1009.0748 and arXiv: 1006.2134
Blind search arXiv: 1009.0748 Up to now few (3) are found also in radio, but it is not easy!
Pulsar timing arXiv: 1007.2183 PSR J1836+5925 18 months timing
Millisecond pulsars PSR J0218+4232 was probably detected by EGRET. With Fermi we now have 11+18 clearly detected in gamma mPSRs. Many “black widows”. No radio-quiet mPSR, yet. Plus, there are 8 gamma-sources coincident with globular clusters. More are coming.
P-Pdot diagram arXiv: 1007.2183 63 PSRs detected by Fermi
Bottom line - 63 clearly detected pulsating PSRs: ~20 radio selected (with 7 known from CGRO time) 24 – in blind searches (several detected also in radio) 27 - mPSRs - 18 mPSRs candidates from radio (non-pulsating in gamma) About radio pulsar population see Lorimer arXiv: 1008.1928 The outer gap models seems to be more probable on the base of Fermi data.