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GeV Gamma-ray Astronomy with GLAST

GeV Gamma-ray Astronomy with GLAST. Outline. GLAST Instruments Overview GeV Gamma-ray Science with GLAST TeV charged particle to produce GeV gamma-rays. Particle acceleration: origin of cosmic rays? Gamma-ray emission mechanisms. AGN GRB SNR Galaxy clusters

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GeV Gamma-ray Astronomy with GLAST

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  1. GeV Gamma-ray Astronomy with GLAST

  2. Outline • GLAST Instruments Overview • GeV Gamma-ray Science with GLAST • TeV charged particle to produce GeV gamma-rays. • Particle acceleration: origin of cosmic rays? • Gamma-ray emission mechanisms. • AGN • GRB • SNR • Galaxy clusters • Gamma-ray emission from WIMP interactions. • GLAST Status H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  3. GLAST LAT Collaboration • France • IN2P3, CEA/Saclay • Italy • INFN, ASI • Japan • Hiroshima University • ISAS, RIKEN • United States • California State University at Sonoma • University of California at Santa Cruz - SCIPP • Goddard Space Flight Center – Lab. for High Energy Astrophysics • Naval Research Laboratory • Ohio State University • Stanford University (SLAC and HEPL/Physics) • University of Washington • Washington University, St. Louis • Sweden • Royal Institute of Technology (KTH) • Stockholm University Principal Investigator: Peter Michelson (Stanford & SLAC) ~225 Members (~80 Affiliated Scientists, 23 Postdocs, and 32 Graduate Students) All countries are still alive at World Cup™ soccer (as of 6/21) H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  4. GLAST LAT Instrument • Tracker: conversion, tracking. • Angular resolution is dominated by scattering. • Converter thickness optimization. • Calorimeter: energy measurement. • 8.4 radiation length. • Use shower development to compensate for the leak. • Anti-coincidence detector: • Efficiency > 99.97%. Si Tracker 90 m2 , 228 µm pitch ~0.9 million channels g e- e+ Anti-coincidence Detector Segmented scintillator tiles 99.97% efficiency CsI Calorimeter 8.4 radiation length H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  5. Thin Thick Thin converters (3%) Thick converters (18%) Thin Thick Full Tkr No converters GLAST/LAT Performance PSF Energy Resolution: ~10% (~5% off-axis) PSF (68%) at 100 MeV ~ 5o PSF (68%) at 10 GeV ~ 0.1o Field Of View: 2.4 sr Point Source sens. (>100 MeV): 3x10-9 cm-2 s-1 (>30 times better than EGRET) Dead time: < 30 µs EGRET Effective area FOV EGRET EGRET H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  6. AGN Science Key Issues. Energetics of the source Jet formation and collimation Particle acceleration Photon emission processes Leptonic Synchrotron self Compton External Compton Hadronic Proton-induced cascades(pp→π0→γγ) Proton Synchrotron (Buckley, Science, 1998) Active Galactic Nuclei (Blazar) H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  7. AGN Variability Studies AGN variability studies. • Size and location of the -ray emission region • Connection to BH, accretion disk GLAST play key role. • All sky survey. • Large FOV • Large effective area • Trigger simultaneous multi-wavelength observation. • Shorter time scale. PKS 1622+297 1996 EGRET flare GLAST simulation H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  8. AGN Population Studies GLAST/LAT All sky EGRET Pointing EGRET detected 70–90 AGNs. GLAST will find thousands of AGNs. • More diversity than EGRET. • Blazar sequence. • AGN evolution. H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  9. AGN as Cosmological Candle • Use thousands of AGNs found by GLAST as cosmological probes. • -rays can be absorbed by interactions with background photons. • GeV photons sensitive to intergalactic UV photons. • Strong dependence on the distance from the source. • History of star formation, large scale structure of universe. No EBL Salamon & Stecker Primack & Bullock Chen, Reyes & Ritz APJ (2004) H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006 Chen, Reyes, and Ritz, ApJ 2004

  10. Gamma-ray Bursts. Cosmological distance Relativistic beaming Supernovae connection 2 or more types? Key Questions. Origin? Hypernovae (long GRB) Binary system merger (short GRB) Jet formation Particle acceleration Photon emission mechanism Gamma Ray Bursts H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  11. GBM Huge field of view (8sr) Measure spectra for bursts from 10 keV to 25 MeV LAT Wide field of view (>2sr) Extends spectral coverage to higher energies GBM and LAT for GRB Observation GLAST can be re-pointed to catch exceptionally bright bursts that occur outside the LAT FOV. BGO NaI • Broadband observation by GLAST. • 6 order of magnitude. • -ray emission mechanisms. H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  12. GRB Delayed Gamma-ray Emission Gonzalez, Nature 2003 424, 749 • Delayed gamma-ray emission from GRB is observed by EGRET. • It is hard to explain by conventional electron synchrotron models. • Proton acceleration? • More samples required to understand further. • Systematic analysis of EGRET data in progress. • GLAST will add much more samples. • GLAST extend the energy reach to ~200 GeV. • Broadband spectra constrain emission models. -18 - 14s EGRET/TASC BATSE 14 - 47s 47 - 80s 80 - 113s Total Absorption Shower Counter 113 - 211s H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  13. TeV Gamma-ray from SNR • HESS TeV gamma-ray observation of RX J1713-3946 • Evidence for particle acceleration > 100 TeV. • Azimuth profile does not match very well with molecular clouds. • Detailed 3D molecular cloud map • Angular distribution from new particle interaction model. HESS/ASCA Aharonian et al. 2005 Aharonian et al. 2005 TeV gamma-ray Molecular clouds H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  14. Gamma-ray Spectrum for RX J1713 • HESS spectrum may prefer hadronic origin. • Not conclusive. • GLAST can positively identify hadronic contribution. • Gamm-rays from π0 decays due to hadronic interaction with molecular clouds. Berezhko 2006 & Aharonian et al. 2005 Bd = 126 µG Kep = 10-4 ESN = 1.8 x1051 erg age = 1600 year GLAST Model independent (π0 production and decay kinematics) — pp→π0→, — Inverse Compton (B=9µG) — Inverse Compton (B=7µG) H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  15. TeV Gamma-ray SNR Candidates 25% Crab 19% Crab 5% Crab 6% Crab 8% Crab 13% Crab HESS ApJ 636 (2006) 777 H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  16. -rays from Merging Galaxy Cluster • Strong shock due minor merger of galaxy clusters. • Model parameters are tuned to be consistent with existing measurements. • Particle acceleration up to 1019 eV. (Origin of UHE-CR?) • Secondary e+e- following proton interaction with CMB photon are dominant origin of gamma-rays. Inoue 2005 ApJ 628, L9 GLAST GLAST can detect IC from secondary e+e- merging galaxy group H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  17. Merging Galaxy Clusters • Large scale shock by merging galaxy clusters. • Origin of Ultra High Energy Cosmic-ray (UHECR)? XMM temperature map (U.G. Briel et al) Abell 3667 Turbulent gas flow Radio emission: Remnant of large scale (>1 Mpc) particle acceleration site X-ray surface brightness H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  18. c q c g q c g c Dark Matter Search with GLAST • Neutralino can be a good dark matter candidate if its mass is in Electro-Weak scale (~100 GeV). • GLAST can be sensitive to the photons from neutralino annihilations. Continuum energy spectrum from π0 decays. Higher statistics… but higher background knowledge of galactic diffuse background is critical Distinct signature A “peak” in the energy spectrum !! Lower background… but lower statistics too H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  19. Dark Matter Search around GC EGRET data shows a hint of neutralino signal around Galactic center. Improved angular/energy resolution, sensitivity and wider energy coverage by GLAST may reveal neutralino signal at Galactic center. Precise measurement of energy cut-off provide definitive signal ofparticle dark matter and its mass. H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  20. GLAST Dark matter spectrum Diffuse background Molecular cloud spectrum Observable Dark Matter Satellite? • High Galactic latitude • Lower backgrounds. • A few clumps may be observable. LSP WIMP (SUSY) GLAST 5-yrs LCC2 LCC4 Wai H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  21. LAT Test Status System Commissioning/ System Test 5/11/06 Shipment 5 days 5/16/06 You Are Here Install Radiators Offload & Set-up LAT Sine Vibe EMI/EMC Test Acoustic Test CPT 5 days 5 days 9 days 11 days 7 days 2 days PER 5/25/06 7/10/06 Remove Radiators T- Bal T- Cycle Pre TV CPT Pack and Ship Weight & CG 3 days 2 days 2 days 2 days 9/15/06 8 days 40 days PSR 9/13/06 H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  22. LAT Before Installing the ACD H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  23. LAT on Shipping Container Base H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  24. LAT Data from Tests at SLAC From A. Borgland Muon candidates Most of the 500 Hz of triggers recorded are muons Photon Candidates ~20% of cosmic ray showers are not muons H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  25. Data Challenges Data Challenges • Originated from particle physics experiment at SLAC (1980’s) • End-to-end test of the data analysis system • Full detector simulation and reconstruction • Two months with celestial sources and instrument backgrounds. • Transient sources. • Merging HEP software and Astro FTOOLS • “Blind “ Analysis • Details of physics not revealed to the collaboration until closeout • Engage the collaboration • to start thinking science H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  26. Summary • GLAST will address questions on the origin of gamma-rays. • Observation of thousands ofAGNsand hundreds ofGRBs. • Models of particle acceleration and -ray emission. • Conclusive proof on the origin of gamma-rays from SNR, RX J1713-3946. • More TeV SNRs will be observed by GLAST. • Constraints on models of particle acceleration inmerging galaxies and galaxy clusters. • Severe constraints onparticle dark mattermodels. • GLAST is on schedule for September 2007 launch. H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  27. More DC2 Slides H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  28. Pulsars • Goal: blind periodicity searches on candidate DC2 pulsars • Goal: Pulsar population studies: the ratio of radio-loud to radio-quiet pulsars. Marcus Ziegler – lightcurves of pulsars withut radio data. Epoch_MET = 220838550 F0 = 3.91691474178 F1 = -1.936137 e-013 F2 = 6.0 e-022 Epoch_MET = 220838550 F0 = 3.766282209980 F1 = -3.677283 e-013 F2 = -3.3 e-021 Epoch_MET = 220838550 F0= 5.885928323969 F1= -1.306230 e-012 F2= 1.0 e-021 H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  29. Source detection algorithms • Requirement: That these algorithms are tested and compared with one another in a systematic way using the DC2 data. • Many source detection methods developed – Stephens, Tosti, Burnett, Casandjian, Ballet, Romeo/Cillis • Compared with one another by Seth Digel H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  30. Gamma-ray bursts This was one of the “rejected” fits due to the strange spectrum. The cause is likely to be because this GRB was simulated with an additional “hard” extended component lasting for 400s. GRB08015885 – Nukri Komin 132 generated in 4p 64 bursts seen in GBM 25 in LAT; 16 with > 4 g H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  31. bright blazar (BPL+EBL) residual background Spectral Studies • Goal: Study spectra of pulsars to determine the shape of spectral cutoffs • Goal: EBL attenuation studies (redshift dependent cutoffs) • Goal: Search for spectral signatures of dark matter Luis Reyes Jennifer Carson H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  32. flux (1day bin) flux (8h bin) Variable Sources Gino Tosti – Taking lightcurves to the next level… H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  33. Image Deconvolution for Diffuse • Poor GLAST PSF make it difficult to resolve RX J1713-3946. • Model independent image deconvolution required. • Image deconvolution is essential for extended sources. • Galactic diffuse, dark matter search, galaxy clusters. • Deconvolved image gives better representation of input image. • Overall shape recovered. Toy MC demonstration GLAST 3.2x1011 s•cm2 observation @ 10-12 erg/cm2/s, ∝E-2, E > 1GeV, PSF = 2.5–27’ Generated image for RX J1713-3946 After smearing by PSF After deconvolution GLAST PSF @1 GeV H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  34. Demonstration with Realistic MC • GLAST Data Challenge II • More realistic Monte Carlo with full detector simulation and reconstruction for 2 months observation. • Event-by-event PSF with tail. • Depends on energy and incident angle. Before deconvolution Input Vela Jr. profile After deconvolution Strong point source can be removed cleanly to observe faint extended sources. (263.55, -2.80) (263.55, -2.79): Vela Pulsar H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

  35. RX J1713 in DC2 Sample (347.86, 0.51) (347.86, 0.51): Pulsar Before deconvolution After deconvolution Generated RX-J1713 profile H. Tajima, GeV Gamma-ray Astronomy with GLAST High Energy Astrophysics in the Next decade, JUN 21-23, 2006

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