Status of pulsar simulation for DC 2

1. Gamma-ray Large Area Space Telescope Status of pulsar simulation for DC 2 Massimiliano Razzano Nicola Omodei GLAST DC II Software Workshop (Goddard Space Flight Center, June 27th-29th 2005)

2. g ray pulsar simulation for GLAST PulsarSpectrum is a simulator developed in Pisa used for simulating gamma ray emission from pulsars Key features: It can reproduce spectra and lightcurves of known g ray pulsars; Flexible architecture to facilitate creation of pulsar sources; Advanced simulation of timing effects due to period changes and motion of GLAST and Earth in Solar System; Full phenomenological model now implemented; Pulsar parameters easy to implement; Capability of simulation of pulsar catalogs; Fully compatible with GLAST-LAT standard software environment (Gleam, observationsSim);

3. Pulsar model Model parameters (phenomenological, physical) ( XML File ) Pulsar Data (Flux,Period,…) (Ascii file) Standalone 2Dim ROOT histo LAT software framework (ObsSim,Gleam) An overview of PulsarSpectrum Simulator Engine

4. Different alternatives for lightcurves: • Random curves (2 Lorentz peaks); • From existing TimeProfiles (useful for simulating known pulsars); • For diagnostic purposes is possible to generate a d-Dirac shaped profile; An output TimeProfile Data file is created ! The phenomenological model (I)lightcurve

5. We choose this analytical spectral shape: (Nel and De Jager,1995): • Description of the high energy cutoff; • Parameters are obtained from fit on the known g ray pulsars (ref. N,DJ95, and DJ 2003); • Flux normalisation based on 3rdEGRET catalog (ph/cm2/s, E>100MeV); • By changing values of the parameters we can simulate different pulsars; Example for Vela-like PSR F(E>100) ~9*10-6 ph/cm2/s, • En=1GeV,E0=8GeV; • g=1.62,b=1.7; The phenomenological model (II)spectrum

6. Lightcurve Spectrum The phenomenological model (III)the final product We combine lightcurve and spectrum:  TH2D ROOT histogram • Now multiplication, but more complicated combination laws are not so difficult to achieve; According to the flux the photons are then extracted and the time arrivals of photons are de-corrected

7. T1 T2 T3 The extraction of the photons:the SpectObj package SpectObj transforms Nn (ph/keV/s/m2) into ph Nn Nn*Adet*Dt*DE Compute also the cumulative function of Nv values in the choosen spectral range P(tk) = SE1,E2Nn(tk,Ek) Next photon is at tN when P(tN ) = 1

8. The Nv is computed is a system where period is constant • We should switch between the “reference systems” S (Pdot is = 0, period constant) S~ (Pdot is not 0, period not constant, e.g. the real world) • Phase assignment in analysis: • # of rotations: • Integrating and taking the fractional part: Period derivatives

9. Barycentric decorretions The first step in data analysis is to transform the photon arrival time at the spacecraft (expressed in MET) to the Solar System Barycenter (expressed in TDB): The simulator must de-correct for these effects: At present 3 main effects are taken into account: • Conversion TTTDB; • Geometric corrections due to lighttravel time from GLAST to Solar System Barycenter • Relativistic delay due to gravitaional field of Sun (Shapiro delay)

10. A tools for managing catalogs (population plots, creation of xml files, etc.) is under development 1-day catalog simulation Simulating pulsar catalogs PulsarSpectrum is also been tested for simulation of many pulsar in the sky. This features allow the possibility to simulate entire pulsar catalog. For each pulsar a log file is produced in order to keep track of the simulated pulsars • Up to now: • simulated catalog of EGRET pulsars • Tests with catalog provided by A.Harding with more than 1k pulsars

11. PulsarDataList XML file ASCII ephem file gtpulsardb Ephemerides fits file Pulsar database For each pulsar simulated in DC2 there must be a correspondant entry in the pulsar database (D4) PulsarSpectrum • PulsarSpectrum next implemented features (under tests) are devoted to interfacing with database: • Multiple entries (that allows the possibility to insert different ephemerides for different periods as in observations) • Output txt file that can be converted with gtpulsardb in a FITS file compatible with SAE standard.

12. 1-day simulation of EGRET pulsar + diffuse emission PulsarSpectrum and Science Tools Testing the SAE Pulsar Analysis Tools Thanks to the simulation of timing effects, like barycentric decorrections) PulsarSpectrum is useful for testing Pulsar Analysis Tools in the SAE (glbary, pulsePhase, gtpulsarDb, stpsearch) Simulations and ScienceTools report in Science Tools 1st Checkout (Oct,12-Oct 29 2004) and 2nd Checkout (Mar,21-Apr,8)

13. 1-week of Crab 1-week of Vela 1-week of 1706-44 (artificial lightcurve ) Some screenshots from Checkout 2

14. Summary for DC2 From http://glast.gsfc.nasa.gov/ssc/dev/psr_tools/testplanDC2.html

15. Status of work • Full simulation code implemented and tested; • Phenomenological model included; • Simulation of period change with time; • Effects of GLAST and Earth motion and of gravitational field of Sun on timing (barycentric de-corrections) • Simulation of EGRET pulsars; • Use of PulsarSpectrum for testing the LAT Analysis Tools for pulsars; • Participation to Science Tools Checkouts. Up to now 1st and 2nd Checkout; • Development of visualization and analysis tool (not included is the Analysis Tool suite); • Work on simulating catalogs of pulsars in preparation for DC2 Summary on Pisa activities on pulsars • Work in progress and plans for future… • Inclusion of more realistic timing effects (timing noise, glitches,etc.); • Development of simulation of binary pulsar systems; • Work with LAT Pulsar Science Group for studying GLAST performances on pulsar science; • Study of analysis techniques for pulsar blind searches; • Work on the development to fit optimally the requirements for DC2 (start January 2006); • Provide output ephemerides database of the simulated pulsars to the DC2 users;

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17. Pulsar simulations: • Refine the model; • Optimize algorithms (simulating pulsars requires lot of time to simulate all timing effects); • Adding more realistic timing effects (multiple ephemerides, timing noise, etc…); • Use EGRET data to simulate known gamma ray pulsars; On going Pisa activities (Pulsars) • Pulsar Data Analysis: • Test Pulsar Analysis Tools for crosscheck the simulationanalysis chain; • Interface with Science Tools group to know simulation requirements and refine the model; • Partecipation to Science Tools Checkout as reviewers for the pulsar tools; • Development of visualisation and analysis tools ( e.g. spectral) as for GRBs. • LAT Pulsar Science: • Partecipation to the PSR/PWN/SNR Science Group; • Plan to work for pre-lauch papers on: • LAT performances on the observation of pulsars; • Expected LAT sensitivity for different pulsars emission scenarios; • Pulsars in DC2: • Development of PulsarSpectrum in order to fit the simulation requirements for DC2 (now this simulator is considered as basis for the pulsars simulation in DC2) • Test of simulation of an extended catalog of fake pulsars; • Include realistic observation conditions (multiple ephemerides, pulsar database); • Provide the ephemerides database of the simulates pulsars to the DC2 users;