Gamma-RayGamma-Ray LineLine ObservationsObservations fromfrom CosmicCosmic NucleiNuclei
Roland Diehl MPE Garching
• Gamma-Ray Line Astronomy: Tools, Objectives, Results • Specific Astrophysical Studies • Diffuse Radioactivity (26Al, 60Fe) • Supernovae (44Ti) • Prospects Gamma-RayGamma-Ray Astronomy:Astronomy: LinesLines ofof InterestInterest
Radioactive Isotopes Decay Time > Source Dilution Time Yields > Instrumental Sensitivities
Isotope Mean Decay Chain γ -Ray Energy (keV) Lifetime
7Be 77 d 7Be → 7Li* 478
56Ni 111 d 56Ni → 56Co* →56Fe*+e+ 158, 812; 847, 1238
57Ni 390 d 57Co→ 57Fe* 122
22Na 3.8 y 22Na → 22Ne* + e+ 1275
44Ti 89 y 44Ti→44Sc*→44Ca*+e+ 78, 68; 1157
26Al 1.04 106y 26Al → 26Mg* + e+ 1809
60Fe 2.0 106y 60Fe → 60Co* → 60Ni* 59, 1173, 1332
e+ …. 105y e++e- → Ps → γγ.. 511, <511
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 Gamma-RayGamma-Ray Astronomy:Astronomy: InstrumentsInstruments
Photon Counters and Telescopes
Simple Detector (& Collimator) (e.g. HEAO-C, SMM, CGRO-OSSE) Spatial Resolution (=Aperture) Defined Through Shield
Coded Mask Telescopes (Shadowing Mask & Detector Array) (e.g. SIGMA, INTEGRAL) Spatial Resolution Defined by Mask & Detector Elements Sizes Focussing Telescopes (Laue Lens & Detector Array) (CLAIRE, MAX) Spatial Resolution Defined by Lens Diffraction & Distance Compton Telescopes (Coincidence-Setup of Position-Sensitive Detectors) (e.g. CGRO-COMPTEL, LXeGRiT, MEGA, ACS) Spatial Resolution Defined by Detectors’ Spatial Resolution Achieved Sensitivity: ~10-5 ph cm-2 s-1, Angular Resolution ≥ deg Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 Gamma-RayGamma-Ray Astronomy:Astronomy: MeasurementsMeasurements
Satellite-Based Surveys and Balloon Experiments Pioneering Space Missions Apollo Gamma-Ray Detector (1977) HEAO-A1 (6 month sky survey, 1978/79) Balloon Experiments UCR, UNH and MPE Compton Telescopes (1978...1982) SN1987A Balloon Programs (1987) Ge Telescopes (HEXAGONE, GRIS, HIREGS) (1980-1998) Xe and Solid-State Detector Compton Telescopes (1995-...) Laue Telescopes (1998-...) Experiments for other Prime Objectives Solar Observatories (SMM, HESSI) (1985-...) “X-Ray” Missions (RXTE, BeppoSax, HETE-II) Compton Gamma-Ray Observatory OSSE & COMPTEL Gamma-Ray Line Surveys (1991-2000)
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 Gamma-RayGamma-Ray Astronomy:Astronomy: ResultsResults
Live Cosmic Nucleosynthesis Detected e+ and 26Al in ISM (Haymes et al. 1976; Matteson et al. 1982) 56Ni and 57Ni in cc-SN (Matz et al. 1988; Kurfess et al. 1992) 44Ti from a cc-SN (Iyudin et al. 1994) 56Co Hints from a SN Ia (Morris et al. 1995) Cosmic Nucleosynthesis Environments Being Studied 26Al throughout the Galaxy (Diehl et al. 1995-2002) 26Al Decay at ~500 km s-1? (Naya et al. 1996) e+ Annihilation in Inner Galaxy (Purcell et al. 1997; Milne et al. 2001) 44Ti Source Limits & Constraints (Schönfelder et al. 2000; Vink et al. 2000) 56Co Limits for a SN Ia (Georgii et al. 2002) 22Na & 7Be Limits for Novae (Iyudin 1995-2002; Harris et al. 2001) 26Al & Massive Stars in Cygnus (Plüschke 2001, Cervino et al. 2002) 26Al from Orion OB1 (Diehl et al. 2002)
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 TheThe SkySky atat 18091809 keV:keV: 26AlAl
Sco-Cen?
Carina Vela Cygnus Inner-Galaxy Ridge Orion Auriga/α Per? Eridanus
Complete CGRO Mission (Plüschke et al. 2001)
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 TheThe COMPTELCOMPTEL 26AlAl ImageImage
Maximum-Entropy Method (“ME”): Global-Entropy-Damped & Misfit-Gradient Driven Iterations Towards Maximum-Likelihood Fit
Multi-Resolution Expectation Maximization Method (“MREM”): Misfit-Gradient Driven and Scale-Hierarchically Noise-Damped Iterations (RL) Towards Maximum-Likelihood Fit
Substantial Image ‘Noise’ (~4o FWHM!) Consolidated Galactic and Localized 26Al Sources
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 26AlAl MapsMaps && PossiblePossible SourceSource TracersTracers
CO map of molecular gas
IR map at 240 µm, dust
Radio map at 53 GHz, free electrons
Hα Emission Different Imaging Methods from Ionized (ME, MREM, MLik) Gas
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 26Al:Al: PlausiblePlausible SourcesSources && OpenOpen IssuesIssues
Massive Stars are Dominating Sources (Diehl et al. 1995; Prantzos & Diehl 1996; Knödlseder 1999) Ionization Correlated to 26Al (free electrons) (Chen et al. 1995) Consistency Check on Massive-Star Outputs: Line-of-sight integrated I1.8MeV = Ifree-free_emission -5 26 Plausible ~8 10 Mo Average Yield of Al per “OV star” 26 Consistent total Al Mass of ~ 2.4 Mo Plausible ~10000 WR Stars in Galaxy But: => SN (II+Ib) rate ~ 1.8/100y (?) Agreement of 1.8 MeV Emission Distribution with Source Tracers Free-Electron Distribution (Pulsars; 53 GHz COBE) , i.e., mainly from Ionization by Massive-Star UV Photons Warm Dust Emission, i.e., from SN and Massive-Star Winds’ Heating of IS Dust (>100 µm COBE) Distribution of Known Massive Stars (i.e., Young Clusters, WR Stars, O Stars) (but: incomplete at d>3 kpc) Irregular Patterns of Massive-Star Locations Observed in LMC, M31; Same as Overall Irregularity of 1.8 MeV Emission? 26Al Disk Latitude Extent > Gas, But < Old Population (=> “puffed up” by SN/Wind Ejection?) Contributions From WR Stars, cc-SNae, Novae, AGB Stars ?
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 TheThe COMPTELCOMPTEL 26AlAl ImageImage
Significances of Map Regions 0.7 37.7 3.9 12.1 13.2 6.4
5.8
7.4
Roland Diehl, Jan 2002 Complete CGRO Mission (Plüschke et al. 2001) Fits of ME Map in ROI, relative to flattened ROI
Image Quality Adequate for Galactic and Localized Analyses of Counterparts
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 MassiveMassive StarStar ClustersClusters andand 26AlAl Diagnostics:Diagnostics: CygnusCygnus
Candidate 26Al sources in the Cygnus region: WR stars, SNR, OB Associations (top view of Galaxy)
Cygnus region OB Associations and Foreground Molecular Clouds
Candidate Sources at <2.5 kpc, Relatively Well-Studied, No Bgd Sources Distance Uncertainties, Occultation (Massive-Star Census Incomplete) Bright Extended Diffuse 26Al Gamma-Ray Emission
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 ModelingModeling 26AlAl fromfrom StarStar ClustersClusters
Stellar Content (OB Association Richness, IMF) Stellar Evolution Lifetime WR Phase 26Al Yields per Star yields 1.809 MeV “Light Curve” for a Massive-Star Cluster plus other Observables UV / Ionization (-> free-free Emission) Kinetic Energy / X Brightness
-> Plüschke et al., 2001; Cerviño et al. 2002
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 MassiveMassive StarStar ClustersClusters andand 26AlAl Diagnostics:Diagnostics: CygnusCygnus
26Al emission at 1809 keV (left), compared to a model map as derived from richness- corrected OB associations and individual known sources (right)
The quality of the 1809 keV fit by different tracers (green) is approximately 1809 keV Images of Source Models of the Cygnus Region: the “raw” achieved with model based on known sources and OB association knowledge (left); astrophysical source the model after correction of OB association richness with CO column models after density normalized on Cyg OB2 (middle); the model after OB adjustment of their association richness correction and accounting for ejecta diffusion characteristics (blue) (right).
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 MassiveMassive StarStar ClustersClusters andand 26AlAl Diagnostics:Diagnostics: OrionOrion
The COMPTEL 9-year Survey Detects Diffuse 1809 keV emission in the Orion/Eridanus Region at ~7σ significance
ME-deconvolved Image: Background-subtracted Count Extended Emission Southward of the Spectra Clearly Show the 1809 keV Orion Clouds Line, Following the Features in the Image
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 MassiveMassive StarStar ClustersClusters andand 26AlAl Diagnostics:Diagnostics: OrionOrion
Massive Stars of the OB1 Association Located at the Edge of the Orion Molecular Clouds Appears to Eject 26 Dust Emisssion (IRAS) and HI Al Radioactivity Trace Neutral Gas Around the into the Eridanus Eridanus Bubble, X-Ray Emission Cavity Traces Hot Gas Inside the Cavity
l=210 Orion A,B
Orion OB1 l=200 Eridanus Bubble
l=185
Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 26AlAl SourceSource VarietyVariety inin LocalizedLocalized Regions:Regions: VelaVela
Model Emissivity Along Galactic Plane
COMPTEL 1.8 MeV C1-9 rod 05/2000 10.00
IR240/10 IR240/4 8.00 free-free/10 free-free/4
6.00
Model Amplitude 4.00
2.00
0.00 180 150 120 90 60 30 0 -30 -60 -90 -120 -150 -180 Galactic Longitude Interesting Nearby Sources in front of Vela Molecular Ridge Vela SNR (d~250 pc) γ2Velorum (WR11) (d~258/400pc) RXJ0852 (200pc Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 26AlAl fromfrom Supernovae:Supernovae: HelpHelp fromfrom 60Fe?Fe? Production in SNae (and Stars) through n Capture on 56,58Fe (s-Process; 13C/22Ne(α,n)) 26Al/60Fe Flux Ratio Limits 0.60 R Diehl 1/99 01/1999: new bgd model; 0.3 syst error, 2sig stat error Decay Time 2 Myr + SN Yields -> 0.50 0.40 Al) Predicted from Theory Iγ ~0.16 Iγ for 26Al from SN only 26 60Fe 26Al 0.30 Fe)/I( 60 0.20 60Fe from 26Al Sources? I( 0.10 0.00 COMP'99 COMPTEL GRIS SMM OSSE 60Fe in Oceanic Crust => Nearby SN ~ 3-5 My ago 26Al in Oceanic Crust? Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 26Al:Al: LessonsLessons aboutabout StarStar ClustersClusters && ISM?ISM? GRIS Ge Detector Balloon Experiment (Naya et al., 1996) Ö Line Width ~6.4 ±1.2 keV, > Instrumental Ö 5.4 keV Doppler Equiv.= ~540 ±140 km/s Interpretations: (Chen et al. 1997; Sturner & Naya 1999) Ö Large Contribution from 26Al in Hot ISM (Loops/Worms/Superbubbles) Ö Fresh Nucleosynthetic 26Al from WR Winds Ö Re-Acceleration of ISM-26Al from Grains at SN Shockfronts Ö Large Fraction of 26Al in Fast Grains % Reflected in 1.809 MeV Line Shape Are: ) Hot Superbubble Interiors ) Very Young Supernova Remnants ) Cosmic-Ray Acceleration Scenarios ) Cosmic Dust Formation Near WR Stars & SN Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 26AlAl Radioactivity:Radioactivity: SummarySummary Massive Stars Dominate Need Model for Massive-Star Population Nucleosynthesis Learn about: Massive-Star / ISM Interaction Pre-Supernova Evolution / Outer SN Individual Source not (yet) Isolated Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 Core-CollapseCore-Collapse Supernovae:Supernovae: 44TiTi fromfrom CasCas AA 44Ti Decay Gamma-ray Fluxes from Cas A 5 4 τ =89y, EC -1 s 44Ti -2 3 τ = 5.4 h, β+ ph cm -5 2 44 Sc 10 I * 1 44 0 Ca COMPTEL 1999 OSSE 1996 RXTE 1997 SAX 2000 44Ti Decay: τ~89y -> Young SNR Difficult γ-Ray Region (78, 68, 1157 keV) -> Uncertain Iγ 44 -4 -> Ti Ejected Mass ~0.8-2.5 10 Mo Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 CasCas A:A: AA Well-StudiedWell-Studied YoungYoung NearbyNearby SNRSNR ~330 year-old SNR at ~3.4 kpc Massive Progenitor (10-25 Mo) Filaments, Fast Ejecta (knots), Fe-rich Clumps, No Onion-Shell- Like Elemental Morphology, Jet: Chandra XMM-Newton Asymmetric Explosion 44Ti (and 56Ni) Ejection ISO Unseen SN -> CSM Dust Central Object (NS/BH?) => (?) Core Collapse SN with Unusual Asymmetries / Hypernova? HST Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 44TiTi EmissionEmission fromfrom cc-SNae:cc-SNae: OpenOpen IssuesIssues Consistency of Cas A cc-SN Model: 44 -5 Ti Yield in Models: ~2-4 10 Mo 44Ti Ejection Should Be Correlated to High-Entropy Material -> a-Rich Freeze-Out Large Explosion Energy Large Mass of Ejected 56Ni (Bright Supernova) -> How Peculiar a cc-SN is Cas A? 44Ti Only From Polar Regions of Accreting Collapse? No 44Ti Sources in Inner Galaxy Small-Number Statistics? Observational Bias? Metallicity Anticorrelation? Can 44Ti Sources Reveal... Inner SN Velocity Profiles? Ionization-Inhibited Decay (EC)? (44Ti Line Shape!) Asymmetric Core Collapses? Hypernovae? Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 RadioactivityRadioactivity YieldsYields fromfrom MassiveMassive StarsStars courtesy Nikos Prantzos 2002 Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 Gamma-RayGamma-Ray LinesLines fromfrom CosmicCosmic Nuclei:Nuclei: SummarySummary Live Cosmic Nucleosynthesis Detected. More? ISM: e+ 26Al; SNae: 56Ni, 57Ni, 44Ti 22Na? Cosmic Nucleosynthesis Environments Being Studied 26Al e+ 511 keV Linie Linie keV 511 44 44 Ti Decay Gamma-ray Fluxes from Cas A Ti 5 4 -1 s -2 3 ph cm ph -5 2 I * 10I * 1 0 COMPTEL 1999 OSSE 1996 RXTE 1997 SAX 2000 56Ni Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002 Gamma-RayGamma-Ray LinesLines fromfrom CosmicCosmic Nuclei:Nuclei: ProspectsProspects Astrophysics: Origin of 26Al, e+, 60Fe -> Massive Stars and SNae Core Collapse SNae: Inner Explosion, Asymmetries Thermonuclear SNae: Deflagration/Detonation Transition Novae: Progenitor Evolution, Mixing? Radioactive Ejecta? Cosmic-Ray Acceleration -> Excitation Lines Observatories: Gamma-Ray Line Shapes -> INTEGRAL Surveys at Improved Sensitivity -> MEGA, ACT Deep SN Measurements -> Laue Tel. Roland Diehl Nuclei in the Cosmos VII, Fuji-Yoshida, 12 July 2002