Gamma-Rays from Supernovae

Transcription

1 Gamma-Rays from Supernovae Roland Diehl MPE Garching Gamma-Ray Line Astronomy and Supernovae Specific Objects Thermonuclear Supernovae ( 56 Co; SN1991T, SN1998bu) Core-Collapse Supernovae ( 44 Ti; Cas A; 26 Al and 60 Fe) Prospects with The COMPTEL Team: Hans Bloemen, Robert Georgii, Wim Hermsen, Jürgen Knödlseder, Giselher Lichti, Dan Morris, Uwe Oberlack, Stefan Plüschke, Jim Ryan, Andrew Strong, Volker Schönfelder, et al. and Karsten Kretschmer, Nikos Prantzos, Dieter Hartmann, Mark Leising, Frank Timmes, Georges Meynet, the SPI Team, et al.

2 Supernova Gamma-Ray Astronomy: Lines of Interest Radioactive Isotopes Isotope Decay Time > Source Dilution Time Yields > Instrumental Sensitivities Mean Lifetime Decay Chain γ -Ray Energy (kev) Source 7 Be 77 d 7 Be 7 Li* 478 Novae 56 Ni 111 d 56 Ni 56 Co* 56 Fe*+e + 158, 812; 847, 1238 Supernovae 57 Ni 390 d 57 Co 57 Fe* 122 Supernovae 22 Na 3.8 y 22 Na 22 Ne* + e Novae 44 Ti 89 y 44 Ti 44 Sc* 44 Ca*+e + 78, 68; 1157 Supernovae 26 Al y 26 Al 26 Mg* + e Stars, Novae Supernovae 60 Fe y 60 Fe 60 Co* 60 Ni* 59, 1173, 1332 Supernovae, Stars e y e + +e - Ps γγ.. 511, <511 Supernovae, Novae,

3 Gamma-Ray Astronomy: Instruments 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

4 SN1987A: First Supernova Gamma-Rays SN1987A 56 Co Decay Gamma-Rays Detected Earlier Than Expected; First Proof of Supernova 56 Ni Synthesis (SMM; Matz et al. 1988) SN1987A 57 Co Decay Gamma-Ray Detection Used to Infer Co Isotopic Ratio (~1.5 x solar) (OSSE; Kurfess et al. 1992; Clayton et al. 1992) SN1987A 56 Co Line at 847 kev Used for Line Shape Analysis (GRIS; Teegarden et al. 1988)

5 56 Ni Decay Gamma-Rays 0+ τ =8.8 d 56 Ni e - -capture (98%) γ 750 kev (50%) γ kev (36%) γ 812 kev (86%) γ 158 kev (100%) τ = d 56 Ni 8.8d 56 Co* 111d 56 Fe*+e + 158, 812; 847, 1238 kev γ-rays Early Envelope γ-transparency (e.g. SNIa within ~30-100d) Direct Measurement of SN Driver γ 847 kev (100%) 56 Fe e - - capture (81%) β + - decay 3,4+ (19%,E~0.6MeV) γ s 3.2,2.8,2.0,1.04, 1.4,1.8 MeV 56 (2-16%) Co γ 1238 kev (68%)

6 SN1991T SN1991T: in NGC4527 on 10 Apr 1991 Distance Mpc Peculiar SNIa early: no Si absorption, Fe emission instead; overluminous; late: ~standard SNIa; overluminous COMPTEL Measurement: Observations at Days 66-79, σ Significance of Line Detection: 11.7 (±3.2 ±2.7) 10-5 ph cm -2 s -1 (all combined) 9(±3) 10-5 ph cm -2 s -1 (847 kev day 70) 6(±2) 10-5 ph cm -2 s -1 (1238 kev day 70) Inferred 56 Ni Mass: ~ 1.65 M o ( M o ) (cmp 1.14 M o from Bolometric Lightcurve, Contardo et al. 2000) Large Uncertainties of Gamma-Ray Flux Measurement Inadequate Spectral Resolution Morris et al., 1995, 1997, 2002

7 SN1998bu SN on May 1..2, 1998 Discovery on May 9.9, Ia Identification on May 14 Host Galaxy M96 / NGC 3368 in Leo I (RA Dec 11 50; l=234.5, b=57.0) ~Closest SNIa: D~ Mpc (D 98bu ~0.7 D 91T ) (Ceph.8.2 by Tanvir et al. 1995(!); Tully-F.~8.1; HST-Ceph.11.6±0.8; PN 9.6±0.6) Standard Type-Ia Lightcurve & Spectra <V Bmax >= > M v = Unusual Reddening (Host Galaxy Dust?) ; Extinction A V ~0.94 ±0.2 mag Whipple Obs; Jha et al., ApJS 125 (1999) Roland Diehl Szuntzeff et al., AJ 117 (1999) The Physics of Supernovae, Garching (D) July 2002

8 SN1998bu: COMPTEL Limits on 56 Ni Decay Lines Georgii et al., Weeks of CGRO Observations (May 19 - Sep ) No Gamma-Ray Line Signal 847 kev Line I spectral < ph cm -2 s -1 I imaging < ph cm -2 s kev Line I spectral < ph cm -2 s -1 I imaging < ph cm -2 s -1 (for 11.3 Mpc; 2σ Limits) I 56Co Lines < ph cm -2 s -1 M 56Ni-visible < 0.35 M o (τ=0 idealized) (bolometric lightcurve -> 0.77 M o, Leibundgut 2000) Fast / Large-Mixing Models (He Cap, W7DT) Unlikely

9 SN1998bu: COMPTEL Limits on 56 Ni Decay Lines Georgii et al., Ni Mass versus γ-ray Flux I 56Co Lines < ph cm -2 s -1 M 56Ni-visible < 0.35 M o (τ=0 idealized) (bolometric lightcurve -> 0.77 M o, Leibundgut 2000) Fast / Large-Mixing Models (He Cap, W7DT) Unlikely

10 Supernova 56 Ni Gamma-Rays Early Envelope γ-transparency (e.g. SNIa within ~30-100d) Gamma-Ray Transport Comparatively Straightforward Line Ratio Diagnostics -> Envelope Structure; Mixing Line Shape Diagnostics -> Velocities of Inner SN Ejecta Instrumental Range: ~15 Mpc (Ia; ~Virgo Cluster) ~ Galaxy & LMC/SMC (Ib/c,II) -> Rare Opportunities Timely Observations are Critical No Real Help on SN Physics Yet, Let s Hope for INTEGRAL et al.

11 Core-Collapse Supernovae: 44 Ti from Cas A Iyudin et al., 1994; The et al. 1996; Rothchild et al. 1998; Vink et al Ti Decay Gamma-ray Fluxes from Cas A τ =89y, EC 4 44 Ti 44 Sc τ = 5.4 h, β + I * 10-5 ph cm -2 s Ca 0 COMPTEL 1999 OSSE 1996 RXTE 1997 SAX Ti Decay: τ~89y Difficult γ-ray Region (78, 68, 1157 kev) -> Young SNR -> Uncertain Iγ -> 44 Ti Ejected Mass ~ M o

12 44 Ti from Cas A / cc-snae: The Issue Timmes et al., 1996 Consistency of Cas A cc-sn Model: 44 Ti Yield in Models: ~ M o 44 Ti Estimate for SN1987A: ~ M o 44 Ti Estimate from γ-rays for Cas A: ~ M o 44 Ti Ejection Should Be Correlated to High-Entropy Material -> a-rich Freeze-Out Large Explosion Energy Large Mass of Ejected 56 Ni (Bright Supernova)

13 Cas A: A Well-Studied Young Nearby SNR Chandra ISO XMM-Newton ~330 year-old SNR at ~3.4 kpc Massive Progenitor (10-25 M o ) Filaments, Fast Ejecta (knots), Fe-rich Clumps, No Onion-Shell- Like Elemental Morphology, Jet: Asymmetric Explosion Unseen SN -> CSM Dust Central Object (NS/BH?) 44 Ti (and 56 Ni) Ejection => (?) Non-Typical Core Collapse SN, Asymmetries The SN with Proven 44 Ti Ejection HST

14 Search for 44Ti from Galactic cc-supernovae The et al., 2000 No 44Ti Sources in Inner Galaxy Parent Distribution of Sources ~ Monte-Carlo Study -> 44Ti SNR Number Low 26Al Small-Number Statistics? Observational Bias? Metallicity Anticorrelation? Roland Diehl The Physics of Supernovae, Garching (D) July 2002

15 44 Ti Emission from cc-snae: Open Issues Consistency of Cas A cc-sn Model: 44 Ti from Models/SN1987A/γ-Rays: ~ M o 44 Ti Ejection Should Be Correlated to High-Entropy Material -> a-rich Freeze-Out Large Explosion Energy Large Mass of Ejected 56 Ni (Bright Supernova) No 44 Ti Sources in Inner Galaxy Parent Distribution of Sources ~ 26 Al Monte-Carlo Study -> 44 Ti SNR Number Low Small-Number Statistics? Observational Bias? Metallicity Anticorrelation? The et al., 2000 Can 44 Ti Sources Reveal... Inner SN Velocity Profiles? Ionization-Inhibited Decay (EC)? ( 44 Ti Line Shape!) Asymmetric Core Collapses?

16 The Sky at 1809 kev: 26 Al Sco-Cen? Auriga/α Per? Cygnus Inner-Galaxy Ridge Carina Vela Orion Eridanus Complete CGRO Mission (Plüschke et al. 2001)

17 26 Al Map & Possible Source Tracers RD with Knödlseder, Prantzos, Oberlack, Plüschke, Bloemen, et al. ( ) CO map of molecular gas IR map at 240 µm, dust Radio map at 53 GHz, free electrons H α Emission from Ionized Gas Massive Stars are the Plausible Sources Map Irregularity and Scale Height, Bright Spiral-Arm Tangents Correlated with Star-Forming Gas Correlated with Warm Dust Correlated with Diffuse Ionized Gas 26 Al Ejection by WR Stars or by cc-snae?

18 Modeling 26 Al from Star Clusters Plüschke Ph D Thesis, 2001 Stellar Content (OB Association Richness, IMF) Stellar Evolution Lifetime WR Phase 26 Al Yields per Star yields MeV Light Curve for a Massive-Star Cluster plus other Observables UV / Ionization (-> free-free Emission) Kinetic Energy / X Brightness WR Stars cc-snae -> Plüschke et al., 2001; Cerviño et al. 2002

19 26 Al from Nearby Supernovae: The Vela Region Model Emissivity Along Galactic Plane COMPTEL 1.8 MeV C1-9 IR240/10 IR240/4 free-free/10 free-free/4 rod 05/2000 Model Amplitude Galactic Longitude Interesting Nearby Sources in front of Vela Molecular Ridge Vela SNR (d~250 pc) RXJ0852 (200pc<d<1500pc) γ 2 Velorum (WR11) (d~258/400pc) Extended Diffuse 26 Al Emission None of These Close SNR Clearly Seen in 26 Al

20 26 Al from Supernovae: Help from 60 Fe? Production in SNae (and Stars) through n Capture on 56,58 Fe (s-process; 13 C/ 22 Ne(α,n)) 26 Al/ 60 Fe Flux Ratio Limits Decay Time 2 Myr + SN Yields -> I γ60fe ~0.16 I γ26al for 26 Al from SN only 60 Fe from 26 Al Sources? ~Little. I( 60 Fe)/I( 26 Al) /1999: new bgd model; 0.3 syst error, 2sig stat error Predicted from Theory R Diehl 1/ COMP'99 COMPTEL GRIS SMM OSSE SN Debris in Solar System? 60 Fe Detected in Seefloor Sediment => Nearby SN ~ 3-5 My ago 26 Al in Sediment, too?

21 Gamma-Ray Lines from Supernovae: Summary Specific Supernova Nucleosynthesis 56 Ni 44 Ti 44 Ti Decay Gamma-ray Fluxes from Cas A 5 4 I * 10-5 ph cm -2 s COMPTEL 1999 OSSE 1996 RXTE 1997 SAX 2000 Accumulated Nucleosynthesis in ISM 26 Al e kev Linie

22 Gamma-Ray Lines from Cosmic Nuclei: Prospects Questions: Origin of 26 Al, e+, 60 Fe Distinguish Massive Stars/SNae Core Collapse SNae: Inner Explosion, Asymmetries Thermonuclear SNae: Deflagration/Detonation Transition Opportunities: Gamma-Ray Line Shapes -> INTEGRAL Launch Oct2002, 1.5 Msec on Cas A, SN87A Surveys at Improved Sensitivity Deep SN Measurements -> MEGA, ACT -> Laue Tel.

23 γ-ray Line Conference / Workshop Opportunities... May 26-31, 2003: Kloster Seeon, Germany Astronomy with Radioactivities IV Feb 16-20, 2004: 5 th INTEGRAL Workshop... München, Germany