1. Marcus ZieglerAPS April Meeting 2006 1 Gamma-Ray Pulsars in the GLAST Era Gamma-ray Large Area Space Telescope Marcus Ziegler Santa Cruz Institute for Particle Physics University of California at Santa Cruz GLAST LAT Collaboration ziegler@scipp.ucsc.edu

2. Marcus ZieglerAPS April Meeting 2006 2 GLAST basic principle Space based pair conversion telescope Energy range of the LAT 20 MeV – 300 GeV Preferred interaction from Gamma-Rays of this energy range is pair-production

3. Marcus ZieglerAPS April Meeting 2006 3 GLAST status All detector components of the LAT (Large area Telescope) are assembled Tracker, Calorimeter, and Anti coincidence detector Picture of the 16 Tracker tower modules of GLAST Launch with Delta 2 rocket is scheduled for Fall 2007

4. Marcus ZieglerAPS April Meeting 2006 4 GLAST Science performance Effective Area 9 000 cm 2 at 10 GeVPSF 68% 100 MeV < 3.5º Source sensitivity 3x10 -9 cm -2 s -1 PSF 68% 10 GeV < 0.15º Field of View 2.4 sr EGRET sky map Simulated LAT (>100 MeV, 1 yr) Simulated LAT (>1 GeV, 1 yr)

5. Marcus ZieglerAPS April Meeting 2006 5 Different pulsar models Polar Cap Models Daugherty & Harding 1982, 1996; Usov &Melrose 1995 High energy spectrum is cut off by magnetic pair production for young pulsars with large B Outer Gap Models Cheng, Ho & Ruderman 1986, Romani 1996 Hirotani & Shibata 1999 More gradual high-energy turnover at about 10 GeV Inverse Compton component up to TeV

6. Marcus ZieglerAPS April Meeting 2006 6 Predictions for different Models Polar CapOuter Gap Radio QuietRadio LoudRadio QuietRadio Loud EGRET8252210 GLAST370363110080 A.K. Harding, Gamma-Ray Pulsars: Models and Population Studies

7. Marcus ZieglerAPS April Meeting 2006 7 Pulsar Blind Searches The third EGRET catalog contains 271 sources. Over 60 sources in the galactic plane remain unidentified. Efforts with super computers to perform periodicity searches did not find new Gamma-Ray pulsars A Search for Radio-Quiet Gamma-Ray Pulsars, A. M. Chandler et. al. APJ, 2001 At UC Santa Cruz we developed a method to reduce the computational power needed to find pulsars. Problems with blind pulsar searches - Long time spans between the detection of photons (~ 1 ph/h for strong sources) - because of the pulsar spin down a huge phase space has to be searched

8. Marcus ZieglerAPS April Meeting 2006 8 Truncated Discrete Auto Correlation Standard method for periodicity searches FFT on EGRET data (one viewing period) for Vela Computing time 260s Truncated discrete auto correlation function Computing time 2s

9. Marcus ZieglerAPS April Meeting 2006 9 Correcting for the spin down Still, to find a Crab like pulsar with a fast spin down of Search for the Crab Pulsar - 3.86 E-10 s -2 a scan in F1 is required. The truncated discrete auto correlation function is not as sensitive to the frequency derivative of a pulsar as a discrete Fourier transform is. Frequency (F0) and Frequency-Derivative (F1) scan in the EGRET data to find the Crab pulsar. The scan took 15min on a standard PC.

10. Marcus ZieglerAPS April Meeting 2006 10 Simulated GLAST Data To test the developed science tools a data set with 55 days of simulated GLAST data was created (Data Challenge 2). Simulated GLAST SKY map with 380 sources About 100 of the simulated sources can be expected to be pulsars. A rough scan of all sources found 12 Radio-Loud Gamma-Ray pulsars Plans for the near future: -> Take an other look at the old EGRET data -> Prepare for the upcoming real GLAST Data