Satellite Experiments for Gamma-Ray Astrophysics

Transcription

1 Satellite Experiments for Gamma-Ray Astrophysics Science Topics for Gamma-Ray Satellites The INTEGRAL Mission & First Results MPE Garching (D)

2 Gamma-Ray Astrophysics from Space No Ground-Based Astronomy for E γ <20 GeV Physical Source Processes at kev GeV:

3 Typical Gamma-Ray Sources Observational Access to Physical Processes in Gamma-Ray Sources Bremsstrahlung Comptonized Emission Line Radiation (atomic & nuclear) Accreting Black Holes Satellite-Exclusive Access: Supernova Remnants Active Galactic Nuclei -> Astrophysics Needs Investment in Space-Based γ-telescopes

4 Astrophysics Topics for Space γ-astronomy Relativistic Astrophysics Hot Plasma Emission Non-Thermal Emission Processes Acceleration of Particles

5 Cosmic Accelerators: The Issues How Does the Acceleration Start? Injection Source Injection Spectrum What is the Time Scale of Acceleration? CR Re-Acceleration? How Do Particles Propagate? Acceleration Region Leaks & Escape Diffusion on Different Scales Observational Tests Diffuse Galactic Gamma Emission SNR, AGN, Microquasars, OB Associations

6 Relativistic Particles & Diffuse γ Emission Diffuse γ-ray Emission e - Scattering on Starlight, CMB e - Bremsstrahlung π o Decay (Nuclear Collisions) CR e - Spectrum Uncertain Standard -> GeV Deficit Harder e - Spectrum Helps But what hardens it? Nonlinear Shock Acceleration? Escape from Sources? Strong, Moskalenko, Reimer 2003

7 Relativistic Particles: Jet Sources Inter-related Emission Processes from Radio (Synchrotron) through X, γ (Bremsstr.; Lines?) TeV (IC) Contemporaneous Observations over Wide Frequency Range

8 Cosmic Nucleosynthesis: The Issues Nuclear Structure, Nucleon Interactions Coulomb Repulsion versus Strong Interaction Collective Interactions, Clusters Reaction Path far from Stability No Data from Nuclear-Physics Experiments Lessons on Nuclear Physics from Astronomy Cosmic Environments of Nuclear Reactions Explosive Heating & Burning Zone Dilution Longterm Evolutions in Stars (Convection) and Interstellar Medium ( chemical evolution ) Nuclear Astrophysics

9 Nucleosynthesis Study with Gamma-Rays Isotope Mean Lifetime Decay Chain γ -Ray Energy (kev) 7 Be 77 d 7 Be 7 Li* Ni 111 d 56 Ni 56 Co* 56 Fe*+e + 158, 812; 847, Ni 390 d 57 Co 57 Fe* Na 3.8 y 22 Na 22 Ne* + e Ti 89 y 44 Ti 44 Sc* 44 Ca*+e + 78, 68; Al y 26 Al 26 Mg* + e Fe y 60 Fe 60 Co* 60 Ni* 59, 1173, 1332 e y e + +e - Ps γγ.. 511, < kev, 7 Be -> Novae -> p-captures, β + Decays -> 19 F Production 26 Al -> Reaaction Path Details in Stars/SNe, ν-process -> Metal/Fe Ratio, Si/Fe 44 Ti, 56 Ni -> Most Stable Isotopes 56 Ni/ 4 He, Freeze-Out of NSE -> Metal/Fe Ratio, Heavies/Fe

10 Astrophysics Topics for Space γ-astronomy Relativistic Astrophysics Hot Plasma Emission Non-Thermal Emission Processes Acceleration of Particles Nuclear Astrophysics Energetic Collisions Radioactivity / Nucleosynthesis

11 Satellite Astronomy with Gamma-Rays Different Science Targets -> Different Missions High-Energy Gamma-Rays ~GeV AGN, Gamma-Ray Blazars Pulsars Galactic Diffuse Emission EGRET.AGILE, GLAST Medium-Energy Gamma-Rays ~MeV Accreting Sources, Pulsars, AGN Galactic Diffuse Emission Nucleosynthesis Sources INTEGRAL ACT Low-Energy Gamma-Rays ~100keV Accreting Sources AGN EXIST Gamma-Ray Bursts HETE-II, SWIFT Solar Gamma-Rays <Astroparticle Physics RHESSI, in Germany, Karlsruhe (D) Sep 2003> NASA/GRAPWG

12 The GLAST Project Large-Area Telescope 18-Plane Si Tracker, 8-Layer CsI Calorimeter 20 MeV-300 GeV, E/E~10% 3.5o 0.15o Resolution, 0.x Src Location Sensitivity 3 x 10-9 ph cm-2s-1 (=EGRET/40) FoV > 2 sr Gamma-ray Large Area Space Telescope Gamma-Ray Burst Monitor 12 NaI, 2 BGO Scintillation Detectors (5 ) 10 kev - 30 MeV Sensitivity 0.3 ph cm-2s-1 FoV ~8 sr γ Pair-Conversion Telescope anticoincidence shield conversion foil particle tracking detectors Launch ~Sep 2006 e+ e calorimeter (energy measurement)

13 The INTEGRAL Satellite INTErnational Gamma-Ray Astrophysics Lab Spacecraft Service Module (common with XMM) Two Coded-Mask Telescopes Side-by-Side Monitors and Auxilliary Sensors at Periphery

14 INTEGRAL in Orbit! 17 October 2002: INTEGRAL Launched (as planned) Status Jan Sep 2003: All Instruments Perform as Expected A Nuclear-Line Spectrometer & γ Telescope in Space!

15 INTEGRAL Scientific Payload ( Instruments ) SPECTROMETER SPI Coded-Mask Telescope with 19-Element Ge Camera IMAGER IBIS Coded-Mask Telescope with fine CdTl and CsI Camera Planes X-RAY MONITOR JEM-X Coded-Mask Telescopes with Imaging Microstrip Gas Detector OPTICAL MONITORING CAMERA OMC INTEGRAL SCIENCE DATA CENTRE ISDC

16 The INTEGRAL Spectrometer (SPI) Coded-Mask Telescope 19 Ge Detectors (5.5x5.5x7cm) BGO Anticoincidence Detector & Shield Stirling Cryocooler Energy Range kev Energy Resolution ~ kev Angular Resolution ~2 arcmin Field-of-View 16x16 o Timing Resolution 52 µs

17 INTEGRAL Observations & Opportunities Core Program Galactic-Plane Survey (weekly, 6 o spaced sawtooth 21 o incl) Galactic-Central-Region Deep Exposure (l=0±30 o, b=0±20 o ) Pointed Observations (Vela Region, ToO) Dithering (Std: 5x5 pattern, 2 o spacing) Exposure -> Opportunities AO-01 February 2001 for Dec 02-Dec 03 AO-02 September 2003 for Dec 03-Dec 04

18 Gamma-Ray Sources in the Galaxy Deep Inner Galaxy Observations Monitor Known Galactic Sources Find New High-Energy Transients Map Diffuse Emission ~9 Ms total exposure Findings: New Sources (~2/month) IGR Mostly Soft Spectra Some Highly Absorbed (N H ~ cm 2 ) -> New Class of Embedded Sources? Revnitsev et al SPI kev von Kienlin; Beckmann; 2003

19 BH Candidates and INTEGRAL: Cyg X-1X Spectrum is Consistent with Comptonization + Reflection + Fluorescence Model (ST 73) Short-term Variability ~Factor 3 Pending: Spectral-Variability Studies Search for Annihilation Feature hot plasma (corona, ~100 kev) cold disk (kev) Pottschmidt et al Bazzano et al Laurent et al Bouchet et al Other sources: GRS , H , Comptonized Hot-Plasma Emission Accretion-Disk Reflection & Fluorescence Emission ISGRI

20 INTEGRAL Gamma-Ray Sources (IGR) IGR J Discovery Jan kev (ISGRI) I~ Crab, Variability δt~1000s XMM/Newton ToO Discovers Weak X-ray Source Highly Absorbed! IGR Sources: (~2/month) Mostly Soft Spectra, but Some Hard at >100 kev -> Pulsars, BH Candidates Some Highly Absorbed (N H ~ cm 2 ) -> New Class of Embedded Sources?

21 AGN Measurement with INTEGRAL: 3C273 Instrument Inter- Calibrations ~Factor 2 wrt XMM/PN: JEM-X 0.61, ISGRI 1.76, SPI 0.95 Power-Law Spectrum Steeper than Average α=1.73 vs. 1.6 (Lichti 95) Dimmer than Average opt vs. 12.9mag, but 1-keV-norm hist.avg Structure Analysis Requires Improved Cross- Calibrations Courvoisier et al. 2003

22 Diffuse Galactic Continuum Multiple Components X/γ Sources (BH Candidates, Pulsars, Microquasars) (thermal and non-thermal components) Positron Annihilation CR Interactions with ISM Gas Strong et al SPI Analysis Method: Multicomponent Model Fitting HI, CO, Gaussian + Sources non-thermal component positronium Skymap Deconvolution; Model Fitting

23 SPI: Spectroscopy in Gamma-Rays local bgd, induced by particles from solar M5 flare on 9 Nov 2002 Comptel Cas A 27Al (3004) Broad 12 C line: γ-ray Narrow 16 O line: nucleus slows emission during down before emitting γ-rays flight 1000 kev

24 SPI: e + Annihilation in the Inner Galaxy INTEGRAL/SPI: 6.1+/-1.1 x 10-4 cm -2 s -1 CGRO/OSSE: 6.5+/-1.5 x 10-4 cm -2 s -1 Jean et al 2003 Knödlseder et al Annihilation of e + (from Radioactivity, Pulsars, Jet Sources ) Annihilation Line at 511 kev, ~ as Expected Emission Region ~Extended without Major Structure

25 SPI: 26 Al Nucleosynthesis in the Galaxy SPI (Diehl et al. 2003) COMPTEL (Plüschke 2001) GRIS (Naya 1996) 26 Al Measurement with SPI: Consistent with Expectations (from COMPTEL etc.) Gamma-Ray Line is Not Excessively Broadened ( GRIS)

26 Timing Measurements with INTEGRAL Consistent Crab Pulsations Timing Accuracy ~100µs Jem X 122 µs, IBIS 61/64 µs SPI 102 µs HE Emission Lags Radio Pulse by ~280±40 µs Jem X: 284±17 µs IBIS : 285±12 µs SPI : 265±23 µs EGRET: 241±29 µs Bridge Emission (between peaks) Increases with Energy Relative Intensity of First Peak Drops with Energy Hz; Rev42/Feb2003 Kuiper et al JEM-X (6-23 kev) ISGRI (20-50 kev) RXTE (2-30 kev) SPI (20-50 kev) PICsIT ( kev) radio pulse main peak = phase 0.0

27 Prospects for Satellite Gamma-Ray Astronomy INTEGRAL and GLAST Will Explore the High-Energy Universe (kev GeV) from Space Nucleosynthesis Accelerated/Relativistic Particle Radiation HE Particle Collisions There Remains a Sensitivity Gap in the 1-10 MeV Region (i.e., where cosmic particle acceleration starts, the suprathermal / injection energy region) See talk by Gottfried Kanbach