1. 06/02/2006M.Razzano GLAST and pulsars: models and simulations Gamma-ray Large Area Space Telescope Astrofisica gamma dallo spazio in Italia AGILE e GLAST ESRIN, Frascati, 3 luglio 2007 Massimiliano Razzano (INFN-Pisa)

2. PulsarSpectrum, simulating pulsars for GLAST Main Features Provide realistic simulations to help developing and testin analysis tools and techniques  Flexible architecture to allow creation of pulsar sources;  Pulsar parameters easy to implement;  PSRPhenom: Phenomenological model;  PSRShape: Simulation of arbitrary energy-phase photon distribution;  Simulation of timing effects;  Full Interface with with LAT software (Gleam, observationSim);

3. Creating the  -E histogram  Photons from simulated pulsars are extracted according to a phase-energy distribution that is specified in a 2D ROOT histrogram (N v )  N v histogram, that depend on the energy E and on the phase  or equivalently time t Є [0,P]).  2 simulation schemes/models can be used for creating it. PSRPhenom -Spectrum S(E) modeled with an analytical formula -Lightcurve L(  ) independently created; - N v (E,  ) = k x L(  ) x S(E); - Normalization k is specified by the user (Flux above 100 MeV);  Simple but some limitations PSRShape -N v dependence on E and  is modeled using available data (EGRET) or prediction from theoretical models;  More complex models and also phase-dependence of spectrum

4. PSRPhenom: simulating lightcurves Lightcurves can be random generated or read from a profile Random curves (Lorentz peaks); Existing TimeProfiles are useful for simulating known pulsars Random peaks Vela EGRET lightcurve (100 bins) Simulation model Lightcurve (2000 bins  44us time bin width)

5. PSRPhenom: simulating spectra I choose this analytical spectral shape: (Nel and De Jager,1995): Description of the high energy cutoff; Parameters are obtained from fits on the known  ray pulsars (Nel, De Jager 1995); Flux normalisation in a similar way to 3 rd EGRET catalog (ph/cm 2 /s, E>100MeV); Example for Vela-like PSR F(E>100) ~9*10 -6 ph/cm2/s, E n =1GeV,E 0 =8GeV; g=1.62 b=1.7 Data from (N&DJ95) b=1 Different scenarios b=2

6. PSRShape:simulating arbitrary models The base phenomenological model (power law + exp cutoff) cannot be used for more detailed phase-energy distribution of photons.  A new model has been implemented PSRShape features External ROOT 2D histogram files can be used Flux normalization can be adjusted; Resulting SC2 phase-dependent Vela (data from EGRET) Service challenge 2 Phase- dependent spectrum model based on EGRET data

7. Timing effects According to energy-phase distribution interval between photons are calculated, but the arrival times are processed for including timing effects. Timing analysis of pulsars is based on analysis steps for applying timing corrections (e.g. barycentering), and phase-assignment. Timing is affected by several effects. These effects must be considered in order to have a realistic list of photons arrival times. Motion of GLAST in Solar System, relativistic effects (barycentering) Period change with time; Ephemerides and timing solutions; Timing noise; Modulation in case of binary pulsars;

8. Barycentric decorretions The analysis procedure on pulsars starts by perfoming the barycentering, i.e. transform the photon arrival times at the spacecraft to the Solar System Barycenter, located near the surface of the Sun In order to be more realistic for the simulations we then must de-correct Several effects that contribute to the barycentering, mainly: Geometrical delays (due to light propagation); Relativistic effects (i.e “Shapiro delay” due to gravitational wall of Sun) Several effects that contribute to the barycentering, mainly: Geometrical delays (due to light propagation); Relativistic effects (i.e “Shapiro delay” due to gravitational wall of Sun) Time [days]

9. Adding Timing Noise Timing noise is an important issue since it affect lightcurves and pulsar blind searches. A basic model of timing noise is includes Several studies and modeling have been proposed for timing noise; For our purposes we choose the model based on Random Walk (Cordes 1980); Cordes Activity parameter A: Noise events occurr at times t i with mean rate R=1day -1 k=0->Phase Noise, k=1=Frequency Noise, k=2,Slow down Noise Example of PN timing noise residuals for simulated pulsar called PSR J1734-3827

10. Pulsars in binary systems Emission from pulsars in binary systems could be much complicate. Since at this stage our purposes are mainly tests of SAE pulsar tools, we paid more attention to orbital motion than to pulsar emission processes First stage implement Keplerian motions, including only: Solution of Kepler’s equation; Roemer delay; Einstein and Shapiro delay already implemented, but no PPN parameters (e.g. g,r parameters) internally computed; The Roemer delay can be seen, in this example of 6 months of sim. PSR J1735-5757 (P orb ≈5.7 d)

11. Filling the D4 file with simulated pulsars PulsarSpectrum is able to take both spin and orbital data of simulated pulsars for creating a D4 database With simulations a summary file is created with names of files containing spin parameters and orbital parameters of the simulated pulsars; These ASCII files can be converted into a single D4 fits PulsarSpectrum SimPulsars_spin.txt SimPulsars_bin.txt SimPulsars_names.txt SimPulsars_summary.txt D4 fits file gtpulsardb

12. EGRET pulsars: lightcurves DC2Geminga, 55d Crab,55d Vela,55d Seeing pulsating pulsars... SC2 Vela,30d

13. Example of simulations PSR B1706-44, 1 months simulation Extracted from SC2 Lightcurve E>100 MeV Lightcurve E> 10 GeV, 15 photons

14. Simulation of PSR B1951+32 Count map Model Lightcurve Spectrum 30 days Sim. observation

15. DC2: Pulsar population Credits:Seth Digel EGRET pulsars (6); 3EG-coincident pulsars (39); Isolated “Normal” pulsars RL or RQ, based on Slot Gap emission (140); Millisecond pulsars RL or RQ based on Polar Cap (229);

16. How many pulsars? Estimates from DC2 ClasseLATCoincLATCoinc 1yearAllRadioPsrAllRadioPsr 1 year No detection13321434 Low confid.143451125 High confid.22543278 EGRET: 6 High Confidence, 3 Low Confidence E>1GeV Low confidence High confidence Pulsars with flux from DC2 LAT catalog

17. LAT studying high-energy cutoff Using XSpec the spectra have been reconstructed for Vela pulsar using 2 different emission scenarios.

18. Conclusions GLAST LAT will be a powerful instrument for studying  -ray pulsars; Only 7 pulsars are known to emit in gamma-rays then statistics is poor; Simulations are a powerful tools for several goals: help development of analysis tools and test new analysis techniques; Study and design focused analyses (e.g. sensitivity); Give rough estimates of LAT capabilities on pulsars; Pulsar simulations reached a good level of detail; DC2 and SCs contain large population of full-detailed pulsars; Ancillary tools have been developed for producing realistic population and sent to PulsarSpectrum; Using PulsarSpectrum, new simulated pulsars will be added in the next simulation runs; Help and support LAT SWG on pulsars with production of focused simulations

19. backup

20. How many pulsars? Estimates from DC2 Low confidence High confidence ClasseLATCoincLATCoinc 1yearAllRadioPsrAllRadioPsr 1 year No detection13321434 Low confid.143451125 High confid.22543278 EGRET: 6 High Confidence, 3 Low Confidence LogN-LogS (see D.J.Thompson ’03) Flux 10 -8 ph(>100 MeV) /cm 2 s counts

21. An overview of PulsarSpectrum Pulsar model Simulator Engine Model parameters (phenomenological, physical) ( XML File ) Pulsar Data (Flux,Period,…) (Ascii datafile) StandaloneLAT software (ObsSim,Gleam) 2Dim ROOT hist

22. PulsarSpectrum structure

23. Pulsars in the LAT catalog: DC fluxes Low confidence High confidence An interesting plot is the LogN-LogS (see D.J.Thompson ’03) The high confidence pulsars follow a similar distribution The low coincidence show a change of slope, mainly because sensitivity effect Slope=-1.04±0.19

25. Period change with time Phase assignment in analysis: # of rotations: Integrating and taking the fractional part: We know that pulsar period changes with time because of loss of rotational energy: We must take this effect into account The interval between 2 photons is expanded according to the period variation.  We switch between the “reference systems” S (P dot is = 0, period constant) S ~ (P dot is not 0, period not constant, the real world)

26. Example of analysis: PSR B1706-44 Lightcurve above 100 MeV Lightcurve 5-10 GeV, 30 photons Lightcurve >10 GeV, 15 photons Good LAT Statistics of LAT at multi-GeV energy (EGRET detected 5 photons above 10 GeV)

27. The Roemer delay in binary pulsars At this first stage the binary MSP have not yet PPN parameters, so that Keplerian approximation is used. The Roemer delay can be seen, in this example of 6 months of PSR J1735-5757 (P orb ≈5.7 d) After phase assignment is applied with binary demodulation the correct lightcurve is recovered

28. The Pulsar Simulation Suite A suite of ancillary c++ classes and ROOT macros for generating pulsar population data to be used by PulsarSpectrum Principal PSS Tools: Population synthetizer: Generate a pulsar population in a phenomenological way using ATNF Radio pulsar catalog and simple theoretical model (up to now only the basic Polar Cap); Ephemerides generator: Create ephemerides and validity ranges using ATNF ephemerides distribution or random; TH2DMaker: create a 2D ROOT histogram that describe the pulsar for PSRShape; PulsarSetsViewer: plot pulsar population data (see plots in this talk); PulsarFormatter: From population data create input files to PulsarSpectrum;

29. PSS Population Synthetizer Starting from an observed population we extract the characteristic of the population we want to simulate. This first approach has a limitation: this empirical catalog didn’t mimic the distribution of radio quiet pulsars. ATNF pulsars Synthetized pulsars

30. The LAT Data Challenge 2 Data Challenges for studying LAT IRFs, reconstruction, exercising analysis tools and techniques (DC1 at end 2003, DC2 in 2006) Full simulation of 55 days of LAT observation in scanning mode; From Kickoff (Mar. 1-3, 2006) to DC2 Closeout (May 31-Jun. 2 2006), where simulation models were revealed Galactic sources (mainly PSR,PWN,SNR,MQs, Solar flare, Moon, WIMP, Galactic diffuse); Extragalactic sources (blazars, GRBs, extragalactic diffuse) ; Pulsar population simulated with PulsarSpectrum (in DC1 only EGRET pulsars as steady sources) DC1 DC2

31. Pulsars in DC2: populations summary The DC2 pulsar population contains 6 sub-populations Pulsars in DC2: EGRET pulsars; 3EG-coincident pulsars; “Normal” pulsars with and without Radio-counterparts (RL+RQ); Millisecond pulsars with and without Radio-counterparts (RL+RQ); We define as Radio-Quiet (RQ) pulsars that does not have a radio counterpart visible because of low radio flux or geometry. We call the others Radio-Loud (RL) Each RL has an entry in the D4 e.g. PSR_JHHMMpDDMM. The RQ have a code DC2_JHHMMpMMDD (available in a D4-format)

32. The EGRET pulsars in DC2 (I) The lightcurves comes directly from the EGRET papers; Spectra are obtained by gamma-ray observations (e.g. Nel,De Jager 1995)

33. The normal pulsars (I) Radio-Loud: 37 pulsars Radio-Quiet: 103 pulsars Generated from the populations synthesis code of Gonthier 2004, and g-ray emission from Muslimov/Harding 2003

34. The normal pulsars (II) The spectral model is the Slot Gap (Muslimov-Harding 2003); We choose a super-exponential cutoff index b ranging from 1.8 to 2.2 (for testing spectral analysis); RQ are generally more far away, the the flux distribution is expected to be shifted; We select pulsars with flux > 10 -9 ph/cm2/s;

35. The 3EG coincident pulsars We included 39 simulated pulsars within 3EG error boxes. Each of them was simulated with Polar Cap emission model (Daugherty&Harding 1998)

36. The millisecond pulsars(I) Radio-Loud: 17 MSP Radio-Quiet: 212 MSP Generated from the populations synthesis code of Gonthier 2004, and  -ray emission from polar cap (Harding 2005)

37. The millisecond pulsars (II) Spectral model with exponential index fixed to 1 (according to model by A.Harding 2005) We increased some fluxes to be sure that users will detect at least some MSP

38. Analysis of DC2 pulsars DC2 pulsars have been analyzed in several different ways, to probe analysis tools and techniques; I will present an automatic system for analysis of large sample of data based on Python script language; Pulsar data have been automatic selected, barycentered and periodicity is tested; Pulsars have been divided in “high-confidence” and “low-confidence” according to results of periodicity test; First analysis on pulsars with couterparts in LAT DC2 source catalog, then on the whole DC2 pulsar database; This system appeared to be a good way to make a first rough processing of large data samples

39. Python scripting: pyPulsar pyGtTools (classes for interfacing with LAT Pulsar Science Tools) pyGtBary pyGtPsearch pyGtEphcomp pyGtPhase pyGtSelect LAT Pulsar Tools pyPulsar (class for managing data and analysis of a pulsar) pyAnScripts (scripts for various pulsar-related analysis) pyPulsar is a set of Python classes and scripts for doing pulsar analysis Analysis results

40. About cuts and thresholds… For each pulsar a specific selection in ROI, energy, etc. can be done; For each pulsar the analysis was performed for 2 energy ranges and with corresponding selection of the ROI according to the PSF; EnergyRadius of ROI E>100MeV3° E>1GeV1° What is the threshold for pulsar detection? After some tests and some discussions I decided to use a more “conservative” detection limits, according to the EGRET pulsars papers Energy  2 chance probability Reference No detectionP > 2 x10 -3 The same as below Low-confidence detection10 -9 < P < 2 x10 -3 Limit of B0656+14 (Ramanamurthy et al. 1996) High-confidence detectionP < 10 -9 Limit of B1951+32 (Ramanamurthy et al. 1995)

41. Effect of selection cuts Cuts give different results depending on pulsar spectrum and on gamma-ray background (most of simulated pulsars are on the Galactic plane); Example of 2 pulsars on the Galactic plane with ~the same flux (10 -7 ph cm -2 s -1 ) Cutoff at  1GeV Cut A Cut B Cutoff at  30GeV Cut A Cut B

42. Pulsars in the LAT source catalog? As first step a search for coincidence between LAT sources and pulsars in D4 (95% radius in LAT Catalog depend on energy, from 2.2° to 0.17°)  49 pulsars found

43. Pulsars in the LAT catalog: summary The first step is the analysis for E>100MeV Low confidence High confidence No detection13 Low confid.14 High confid.22 Low confidence High confidence 10 14 G 10 3 yr 10 9 G 4 MSP detected at high confidence and 1 at low confidence (B 10 9 y)

44. Beyond the LAT catalog The next step is the scan on the entire D4 database. First for E>100MeV E>100MeV No detection42 Low confid.26 High confid.29 No detection38 Low confid.34 High confid.25 E>1GeV Low conf High conf

45. Beyond the LAT catalog:population E>1GeVE>100MeV More MSP at E>1GeV (Spectral shape) No detection14 Low confid.51 High confid.32 After merging E100MeV and E1GeV results

46. LAT Studying the high-energy cutoff Polar Cap models and Outer Gap models predict very different spectral cutoff; Studying this cutoff is one of the the best way to constraint models; LAT will have high energy resolution and wider energy coverage and should be optimal for studying the cutoff; Using simulations a preliminary work using Vela pulsar has ben prepared; Vela pulsars using 2 models (PC and OG) have been prepared; Vela PC at real position, and a Vela OG at simmetric position with respect to the Galactic plane. Background due to diffuse emission is negligible; Simulated time scales of 1week,1,3,6 months, 1 year; Spectral analysis using Xspec v12; An estimate of the energy range where the difference is higher is given; An estimate on the time scale required for distinguish between models;

47. Simulation model of Vela Phase-averaged spectra of Vela using Polar Cap model of Daugherty & Harding, 1996 (simulation with PSRShape) Phase-averaged spectra of Vela using Outer Gap model of Romani, 1996 (simulation with PSRShape)

48. An example of Vela spectral cutoff Example of 1 year LAT observation in scanning mode

49. Difference between models In order to study how the spectral cutoff difference can be seen by the LAT at increasing observation time, I used the quantity: And the difference divided by the errors, that should be an estimate of difference in “sigmas” 1-month observation

50. Observaton time scales Interpolations to see where 3  and 5  are reached; Balance between the quantity D PC - OG and the its errors; Best energy band at  10 GeV; Almost 10  for 1 year; T 3  ≈12 days T 5  ≈4 months Preliminary study, need to be expanded with refined analysis and try other statistical indicators

51. Conclusions GLAST LAT will be a powerful instrument for studying  -ray pulsars; Only 7 pulsars are known to emit in gamma-rays then statistics is poor; Analysis tools for LAT data are at a good level of development; Detailed simulations are useful for several reasons (testing tools and analysis, prospect for focused analysis, developing analysis techniques); PulsarSpectrum is an high-detail pulsar simulator that is used by the LAT Collaboration for studying LAT response; DC2 has been an important milestone to test new analysis techniques, such as automated analysis; An example of automated processing of pulsars have been developed and tested; LAT capability of study the high-energy cutoff is and example of how simulations can help in studying analysis issues and predictions;

52. Backup Slides

53. The case of Geminga Discovered by SAS-2 in the Galactic anticenter In the COS B era identification with an unusual Einstein X-ray source, 1E0630+178 (Bignami, Caraveo, Lamb 1983) with L x /L v ~1000 and lack of radio counterpart. It is Geminga! Gamma-ray periodicity found in EGRET data and then also in SAS-2 and COS B Marginal detection of radio counterpart at 102 Mhz (1999). No successive confirmations; No unpulsed emission observed; Phase-resolved spectroscopy; phase-averaged spectral index of -1.5 Cutoff above 2 GeV Corrections due to proper motion improved the lightcurve Bignami & Caraveo 1983 No radio counterpart: search for periodicity around 237 s. EGRET llghtcurve (Mayer- Hasselwander et al. 1993)

54. Identikit of a DC2 pulsar: the MC truth For every pulsar in DC2 a correspondant “ID card” has been produced These ID contains infos about main properties of simulated pulsar Ephemerides validity range was chosen to contain the 55 days for most pulsars (but not for all…) These are available on the Web, and were used at DC2 Closeout to compare with analysis results

55. The EGRET pulsars in DC2 (I) The lightcurves comes directly from the EGRET papers; Spectra are obtained by gamma-ray observations (e.g. Nel,De Jager 1995)

56. The EGRET pulsars in DC2 (II) For weakest EGRET pulsars we keep the original binning. No further interpolations..

57. An example of flux limit Spectrum and flux depends on the theoretical model you choose to adopt Start from Polar Cap model, as in Harding & Zhang (2000), and Gonthier et al. (2002) We obtain the luminosity L gamma, the spectral index and an estimate of the cutoff energy for the power law. Then we slightly modify the spectra in order to have an exponential cutoff of ≈2. LAT sensitivity EGRET sensitivity This is a rough estimate!

58. Pulsar population  max  EGRETfits from de Jager et al. (2002) 3EG coincident Simulated normal Simulated ms 2/3 1 Fitting formula (de Jager et al. 2000) Spectral simulation

59. Silicon Microstrip detector (SSD) Tray (composite structure: Si layer, W conversion foil, mech.structure, DAQ electronics) The LAT Silicon tracker The tracker of the LAT is based on Si microstrip technology and can reach an high angular resolution. Array of 4 x 4 identical towers (~82m 2 Si, total of ~ 1M channels) Tracker assembly is under responsability of Italian collaboration LAT ~3.5° @100MeV, 10GeV ~2.4 sr EGRET 5.8° @100MeV, 0.5 sr Ang. Res. F.O.V. Tower (19 trays)  18 sensitive XY layers 12XY layer FRONT 3 %X o 4 XY layers BACK 18 % X o

60. Simulating the Radio Pulsar Population Monte-Carlo population synthesis (Gonthier et al. 2004) - evolve neutron stars in the Galaxy, assuming uniform birth rates for normal and ms pulsars Birth distributionNormal pulsarsMillisecond pulsars Period Uniform 0-150 ms On spin-up line P min = 0.7 ms Magnetic field Double Gaussian logB 0 = 12.75, 13 Field decay, t=2.8Myr Kick velocity Bimodal Arzoumian et al. (2002) Spatial Galactic distribution of Paczynski (1990) Chernoff & Cordes 1999

61. E (MeV) CR production and acceleration in SNR GLAST simulations showing SNR  -Cygni spatially and spectrally resolved from the compact inner gamma-ray pulsar – a clear  0 decay signature from the shell would indicate SNR as a source of proton CR locate SNR resolve SNR shells at  10 level measure SNR spectra GLAST will SNR widely believed to be the source of CR proton acceleration after shell interaction with interstellar medium  0 bump in the galactic spectrum detected by EGRET

62. Halo WIMP annihilations If SUSY uncovered at accelerators, GLAST may be able to determine its cosmological significance quickly. If true, there may well be observable halo annihilations q q  or Z  lines X X Good particle physics candidate for galactic halo dark matter is the LSP in R-parity conserving SUSY Example: X is  0 from Standard SUSY, annihilations to jets, producing an extra component of multi-GeV  flux that follows halo density (not isotropic) peaking at ~ 0.1 M   0 or lines at M  0. Background is galactic  ray diffuse. ~ ~ ~

63. Halo WIMP annihilations  lines 50 GeV 300 GeV Total photon spectrum from the galactic center from  ann. Infinite energy resolution GLAST two-year scanning mode With finite energy resolution

64. Outline GLAST and the gamma-ray Universe; The GLAST Large Area Telescope; GLAST and gamma-ray pulsars; The PulsarSpectrum Simulator; Simulating timing effects; Pulsar Data Analysis: examples from simulated EGRET pulsars; Pulsar simulations for the LAT Data Challenge 2; Analysis methods for Data Challenge 2; Studying the pulsars spectral cutoff; Conclusions;

65. Time resolution:  Search for Periodicity  Correlation with other Pulsars studies with GLAST Pulsars in EGRET era  Sensitivity + Energy resolution:  Test models (e.g. polar cap vs outer gap)  Discovery of new Pulsars (~250) EGRET obs. Of Vela (Thompson et al. 1999) + GLAST simulation (Daugherty, Harding 1996, Romani 1996)

66. EGRET low-confidence Periodicity chance probability ~ 5 orders of mag. less then the faintest high-confidence EGRET pulsar; PSR B1046-58, maybe counterpart of 3EG J1048-5840 has an associated X-ray source not pulsed (kaspi et al., 2000). PSR B0656+14 has pulsed emission in optical and X-rays. Not coincident with any 3EG source (Ramanamurthy et al., 1996); PSR J0218+4232 is the only MSP with some evidence of pulsation. Spatial analysis complicated because of a nearby BL Lac 3C66A (1° away) (Kuiper et al. 2002). (From D.J.Thompson, 2003)

67. Pulsars at GeV energies (From D.J.Thompson, 2003) No pulsed emission seen at TeV energies; Evidence for pulsed emission above 5 GeV for Crab, Vela, Geminga and PSR B1706-44, and the others are consistent with pulsed emission; One of the 2 pulses fade at highest energies; except in PSR 1706-44 is the trailing one; Except for Crab emission is concentrated in the peaks; the extended emission of Crab is tought to be unpulsed SNR emission; Too few photons at high energy: for Vela only 4 photons of 10-30 GeV with 50% uncertainty; The gap from 10 GeV and ACT energies is very important to constraint the emission models. GLAST will observe this energy gap.

68. Some simulated binary pulsars 3 fake MSP from DC2 put into binary orbits PSR J1735-5757 P=6.8 ms P orb =5.7 d E=0.78 PSR J1710-3408 P=9.5 ms P orb =2 d E=0.52 PSR J1839+0210 P=7.2 ms P orb =0.4 d E=0.8

69. Simulating pulsar catalogs PulsarSpectrum is also been tested for simulation of many pulsars in the sky. This feature allows the possibility to simulate entire pulsar catalogs. For each pulsar a log file is produced in order to keep track of the simulated pulsars Examples: Simulated mini-catalog with EGRET pulsars; DC2 catalog based on synthesis code (P.Gonthier and A.Harding used for LAT DC2) A tools for managing catalogs (population plots, creation of xml files, etc.) has been developed 1-day catalog simulation (  1000 pulsars)

70. Experimental Technique Instrument must measure the direction, energy, and arrival time of high energy photons (from approximately 20 MeV to greater than 300 GeV): - photon interactions with matter in GLAST energy range dominated by pair conversion: determine photon direction clear signature for background rejection  e+e+ e–e– calorimeter (energy measurement) particle tracking detectors conversion foil anticoincidence detector Pair-Conversion Telescope Energy loss mechanisms: - limitations on angular resolution (PSF) low E: multiple scattering  many thin layers high E: hit precision & lever arm must detect  -rays with high efficiency and reject the much larger (~10 4 :1) flux of background cosmic-rays, etc.; energy resolution requires calorimeter of sufficient depth to measure buildup of the EM shower. Segmentation useful for resolution and background rejection.

71. The LAT calorimeter Measure: Energy :res. <10% (100MeV<E<10 GeV),< 6% (10GeV<E<300GeV) Shower direction  matching with Tracker Direction of photons that miss the conversion in Tracker (res. Few degrees) Basic concepts: 1536 crystals (total) 2x2.7x33 cm 3 Self-triggering 8.5 X 0 total 12 x 8 layers of CsI bars  hodoscopic configuration Lateral and longitudinal segmentation  Good e.m. shower reconstruction

72. LAT Anticoincidence Detector  Background rejection: 3x10 3 : 1  Segmentation to avoid Self Veto 89 plastic scintillator panels read by 2 PMT Use of Wavelenght Shifters

73. Pulsars in multi- Credits:G.Kanbach Radio: ~1700 Optical: 5 X-Rays:~70 Gamma-rays: 7 Combinations of telescope sensitivity, geometry and physics..

74. How many pulsars with GLAST? The number of pulsars that GLAST will see depends strongly on the emission scenario. Hovewer estimates show that the number of new pulsars will be from tens to hundreds; GLAST LAT statistics will permit blind searches for Geminga-like pulsars; Credit: D.Thompson

75. EGRET pulsars characteristics (From D.J.Thompson, 2003) 7 high confidence gamma-ray pulsars Low confidence gamma-ray pulsars Concentrates in high B region; Young ages; High Open field line voltage; Not yet gamma millisecond pulsar discovered at high confidence;

76. Science Performance Requirements Summary From the Science Requirement Document: ParameterSRD ValuePresent Prediction Peak Effective Area (in range 1-10 GeV)>8000 cm 2 10,000 cm 2 at 10 GeV Energy Resolution 100 MeV on-axis<10%9% Energy Resolution 10 GeV on-axis<10%8% Energy Resolution 10-300 GeV on-axis<20%<15% Energy Resolution 10-300 GeV off-axis (>60º)<6%<4.5% PSF 68% 100 MeV on-axis<3.5°3.37° (front), 4.64° (total) PSF 68% 10 GeV on-axis<0.15°0.086° (front), 0.115° (total) PSF 95/68 ratio<32.1 front, 2.6 back (100 MeV) PSF 55º/normal ratio<1.71.6 Field of View>2sr2.4 sr Background rejection (E>100 MeV)<10% diffuse6% diffuse (adjustable) Point Source Sensitivity(>100MeV)<6x10 -9 cm -2 s -1 3x10 -9 cm -2 s -1 Source Location Determination<0.5 arcmin<0.4 arcmin (ignoring BACK info) GRB localization<10 arcmin5 arcmin (ignoring BACK info)

77. In many models, galactic cosmic rays (CR) are produced and accelerated in supernova remnants (SNR) from shell-ISM interactions GLAST and Cosmic Rays physics Distinguish between acceleration sites (shell or compact object) Spectral components (e.g.  0 bump @ 70 MeV) The contribution from GLAST data: Angular and spectral resolution Simulation of GLAST obs. Of Gamma Cyg SNR (GLAST Science Doc) Gamma ray spectrum model of IC443 adapted from Baring et al. 1999

78. Halo WIMP annihilations  lines 50 GeV 300 GeV Total photon spectrum from the galactic center from  ann. Infinite energy resolution GLAST two-year scanning mode With finite energy resolution

79. All-sky count map of the simulation of 55 days for DC2 E>200MeV ROI with R=3° Periodic at C.L. > 99.99% E>100 MeV ROI with R=1° Periodic at C.L. > 99.85% E>100MeV ROI with R=3° Periodic at C.L. > 99.99% E>100MeV ROI with R=3° Periodic at C.L. > 99.99% E>100MeV ROI with R=3° Periodic at C.L. > 99.99% E>300MeV ROI of R=1.5° Periodic at C.L. > 99.99%

80. GLAST and the study of AGN The contribution of GLAST: High sensitivity  ~ 3000 new AGN discovered Energy resolution  Identification of leptonic (SSC,ECS) and hadronic contribution ( e.g.  0 decay) Time resolution  emitting region size estimation Multiwavelenght studies with radio, IR, visible, X Enormous luminosity (10 49 erg/s) from a compact volume (~100 A.U.) Luminosity fluctuations (< day) High collimated relativistic jet of particles Standard Unified Model Accretion on supermassive black hole (10 6 - 10 10 M sun ) EGRET obs. of flare of blazar PKS1622-297 (Mattox et al. 1997) and sim. GLAST obs.

81. Testing the telescope with real cosmic ray data

82. Identifying Sources Counting stats not included. Cygnus region (15 0 x 15 0 ), Eg > 1 GeV GLAST 95% C.L. radius on a 5  source, compared with a similar EGRET observation of 3EG 1911-2000 GLAST high resolution and sensitivity will: resolve gamma-ray point sources at arc-minute level detect typical signatures (e.g. spectra, flares, pulsation) for identification with known source types 170/271 3 rd EGRET catalog still unidentified

83.  e+e+ e-e- Lessons learnedEGRETGLAST-LATpositive impact on INSTRUMENTmonolithicmodular 4x4 towereffective area A eff TKRmonolithic4x4 towertrigger, A eff CALmonolithichodoscopicbkgrd. rej., long. profile recon. ACDmonolithicsegmentedself-veto@ high E, bkgrd. rej. TRIGGERTOF+ACDself TKRorCAL no ACD aspect ratio, FOV, L1T rate: from pure  trigger (~fewHz) to any track (~30KHz) TKR TECHNOLOGYspark chamber si-stripinstr. dead time, PSF, high trigger rate and lifetime(no need to save consumables) LAT and EGRET EGRET 1991-2000GLAST 2007 on.. 30Mev-30GeV Peak A eff 1500cm 2 (on-axis) 20Mev-300GeV Peak A eff 10000cm 2

84. An example of Pulsar Catalog We started to take pulsar data from the database of the Australian Telescope National Facility. http://www.atnf.csiro.au/research/pulsar/

85. Examples of lightcurves: PSR B1055-52 and PSR B1951+32 PSR B1951+32 50 bins  1000 bins (bin width~40us) PSR B1055-52 30 bins  3600 bins (bin width~50us)

86. Filling the D4 file with simulated pulsars PulsarSpectrum is able to take both spin and orbital data of simulated pulsars for creating a D4 database With simulations a summary file is created with names of files containing spin parameters and orbital parameters of the simulated pulsars; These ASCII files can be converted into a single D4 fits file using gtpulsarb PulsarSpectrum SimPulsars_spin.txt SimPulsars_bin.txt SimPulsars_names.txt SimPulsars_summary.txt D4 fits file gtpulsardb

87. Example of analysis: PSR B1706-44 Counts predictions and integrated flux using maximum likelihood within 20°

88. An example of flux limit Spectrum and flux depends on the theoretical model you choose to adopt Start from Polar Cap model, as in Harding & Zhang (2000), and Gonthier et al. (2002) We obtain the luminosity L gamma, the spectral index and an estimate of the cutoff energy for the power law. Then we slightly modify the spectra in order to have an exponential cutoff of ≈2. LAT sensitivity EGRET sensitivity This is a rough estimate!

89. The isolated “normal” pulsars Pulsar population Population produced by synthesis code (Gonthier et al. 2004); Birth period uniform from 0-150 ms, and birth rate assumed constant; Magnetic field from bimodal gaussian distribution in log(B); Evolution in gravitational potential; Two-component radio beam; Alignment and view angle random extracted; Radio flux computed and compared with radio survey to decide wheter a pulsar is RL or RQ; Slot Gap gamma-ray emission from pair cascades (Muslimov/Harding 2003); Gamma-ray emission Slot Gap gamma-ray emission from em pair cascades (Muslimov/Harding 2003); Variation of the Pair Formation Front with altitude (PFF), above which E II is screened (pairs prod.) Calculation of flux, spectrum and energy cutoff due to photon absorption in magnetic field; Selected those pulsars with flux higher than 10 -9 ph cm -2 s -1 ;

90. The DC2 Millisecond Pulsars Pulsar population Population produced by synthesis code similar to those for Isolated pulsars; Magnetic field distribution, kick velocity distribution and evolution in galactic potential; Periods along spin-up line (Gonthier 2004) Gamma-ray emission Polar Cap emission from Harding 2005; MSP are below dead line for CR pair production but above dead-line for pair production from IC photons from accelerated particles on thermal X-ray emission; Low multiplicity, then pairs cannot screen E || and acceleration proceed to high altitudes, where particle acceleration is radiation-limited; Fluxes and spectrum computed from this model;

91. Vela phase-dependent spectrum Real data from Fierro et al. 1998 + High-E tail Phase-dependent spectra for the resulting Vela model histogram Matching spectra and lightcurve: Good agreement

92. Vela phase-dependent spectrum Real data from Fierro et al. 1998 + High-E tail Phase-dependent spectra for the resulting Vela model histogram Matching spectra and lightcurve: Good agreement

93. Example of Vela pulsar with PSRShape EGRET lightcurve (100 bins) Lightcurve (2000 bins  44us time bin width) Normalization is adjusted by PulsarSpectrum during the simulation according to the flux for E> 100 MeV Smoothing

94. PulsarSpectrum structure