Gamma-Ray Spectroscopy with INTEGRAL - Observations and their Interpretations -

Transcription

1 Gamma-Ray Spectroscopy with INTEGRAL - Observations and their Interpretations - MPE Garching Astrophysics with γ-ray Lines Studies of Sources of Nucleosynthesis: Supernovae and Novae Massive Stars Positrons

2 Gamma-Rays: Messengers of Nuclear Physics Nuclear Energy Level Transitions -> Gamma-Ray Line Emission Energies ~MeV (kt~10 9 K) ("non-thermal") Isotope Identification

3 Gamma-Ray Astrophysics: Basic Processes Physical Source Processes at kev GeV:

4 Astronomical Observations throughout the e.m. Spectrum Radio- Waves Infrared Radiation Optical Light UV Radiation X-Rays Gamma-Rays 100km 50km 10km Reflection CO 2,H 2 O,O 3... Absorption Bands due to O 3, N, O log 10 log 10 λ

5 Radiation from Cosmic Sources Thermal Radiation Atomic Transitions Nuclear Transitions Matter/Antimatter Annihilation INTEGRAL / SPI 511 kev Non-thermal Processes HESS

6 Examples of a Science Goal (1) Messengers from the Deep Interior of a Supernova Shell-Structured Evolved Massive Star Gravitational Core Collapse Supernova Shock Wave Shock Region Explosive Nucleosynthesis Location of Ejecta/Remnant Separation 44 Ti Produced at r < 10 3 km from α-rich Freeze-Out, => Unique Probe (+Ni Isotopes) Proto-Neutron Star Neutrino Heating of Shock Region from Inside 3D-Effects Important for Energy Budget AND Nucleosynthesis

7 Examples of a Science Goal (2) Cycling of Matter and 26 Al (τ~10( 6 y) M~ M o 10 8 y condensation dense molecular clouds star formation (~3%) interstellar medium stars y M > 0.08 M o infall y dust dust winds SN explosion mixing Galactic halo outflow SNR's & hot bubbles y ~90% SNIa compact remnant (WD, NS,BH) Make non-radiating ISM Visible

8 Gamma-Ray Lines for Nucleosynthesis Study Radioactive Trace Isotopes as Nucleosynthesis By-Products For Gamma-ray Spectroscopy We Need: Decay Time > Source Dilution Time Yields > Instrumental Sensitivities 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, <511

9 Gamma-Rays: Messengers of Nuclear Physics Special Characteristics: Emission due to Radioactivity No Activation (thermal, ionization) Isotopic Information Related to Specific Nuclear Reactions Penetrating Radiation No Occultation Corrections

10 Gamma-Rays: Messengers of Nuclear Physics Special Characteristics: Emission due to Radioactivity No Activation (thermal, ionization) Isotopic Information Related to Specific Nuclear Reactions Penetrating Radiation No Occultation Corrections Penetrating Radiation Poor Imaging Resolution (deg arcmin) Low Signal, High Background Galactic Sources, SN Ia < 10Mpc

11 Gamma-Ray Astronomical Telescopes: Interaction of HE Photons with Matter Photon interaction with matter (Pb)

12 Gamma-Ray Astronomical Telescopes: Interaction of HE Photons with Matter Photon interaction with matter (Pb) Seconday photons / electrons -> multi-element & tracking detector assemblies -> Secondary Particles -> e.m. cascade

13 Instruments for Gamma-Ray Astronomy Photon Counters Imaging Telescopes Simple Detector (& Collimator) Coded Mask Telescopes (Shadowing Mask & Pixelated Detector) few MeV Focussing Telescopes (Laue Lens) MeV Compton Telescopes (Coincidence-Setup of Position-Sensitive Detectors) 0.5 MeV Achieved Sensitivity: ~10-5 ph cm -2 s -1, Angular Resolution deg

14 INTEGRAL Operates in Space! 17 October 2002: 06:41 Launch of Integral from Baikonur / Kasachstan 12:00 INTEGRAL safely on its way, all systems normal Status Today (Early 2006): No Major Failures, Mission Horizon 2008 (ESA approved) >2010

15 ESA s INTEGRAL Spacecraft Two Coded-Mask Telescopes Side-by-Side Monitors and Auxilliary Sensors at Periphery Low-Background Elliptical 72-hr Orbit Observatory for Point Sources & γ Lines ( kev)

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 Source Location to ~2 arcmin Field-of-View 16x16 o Timing Resolution 52 μs

17 Casting a Source Shadow: The INTEGRAL/SPI Coded Mask Telescope A Semi-Transparent Mask Occults Part of the Position-Sensitive Gamma-Ray Detector Plane Recognition of the Mask Shadow in the Detectors Signal -> Imaging a Source Telescope = Mask & Detector Hardware + Imaging Software Masks Uniformly-Redundant Arrays (Adapted to Detector Sizes) -> Larger Field of View Partially/Fully Coded FoV Imaging Correlation Fourier-Domain Filtering Iterative Model Fitting ref. e.g.: Skinner Source Mapping in Large Sky Areas but: Diffuse Emission?

18 SPI Sensitivity for Gamma-Ray Lines 3σ narrow line sensitivity (photons s -1 cm -2 ) HEAO3 OSSE SPI COMPTEL T obs = 10 6 s E (MeV) 1 The early estimate had ignored the instrumental line contributions Pulse Shape Rejection of background is less effective than estimated

19 Diagnostics of Supernovae Type Ia

20 A Hot Issue : : Are SNIa Standard Candles? Branch, 1998; 2003 Spectra and Light Curves are Surprisingly Homogeneous (after normalization by decline in B band) Need a Well-Regulated Process/Event Type, Producing Much Fe Diversity Can Be Recognized, Nevertheless

21 What Makes a Supernovae Ia SN Ia Models Close Binary System WD Giant White Dwarf Merger Binary Mass Transfer WD at M Ch C/O Layer He Layer SN Ia Central C Ignition He Shell Flash

22 How Does a SNIa Explode? C Ignition at M Ch Limit (possibly many ignition points) Turbulent Flame Propagation WD Expansion -> Flame Extinction Issues: Rapid Time Scales! Nuclear Burning C+O-> 56 Ni Expansion Mixing

23 Issues Around a Thermonuclear WD Explosion Flame Propagation Slow Flame Fizzles, Fast Flame at ρ>10 7 g cm -3 Yields Ni Only Deflagration -> Detonation Transition -> Fe/Ca Element Ratio Chemical Composition of Accreted Matter C/O (WD Merger): Rapid C Burning. But: Accretion-Induced Collapse or SN? -> Sub-Ch Progenitors He: off-center C Detonation after He Flash -> Sub-Ch Progenitors H: Accumulation of Matter? (M ej(nova) ~M accr ) -> Supersoft XRS Accretion Rate Build-Up Fuel Layer for Explosion. How Slow? e.g.h: Novae (dm/dt < 10-9 M o yr -1 )? Flashes? Steady Burning? Common Envelope (dm/dt > 10-6 M o yr -1 )? e.g.he: 10-9 < dm/dt < 5x10-8 M o yr -1 Need Sufficient # of WD s, Consistent with SNIa Event Rate Key Measurements: E kin, E radioactive (Ni Mass, Envelope Structure), Ejecta Composition

24 Gamma-Rays from Supernovae Ia Rarely SNIa 56 Ni Decay Gamma-Rays are Above Instrumental Limits (~10-5 ph cm -2 s -1 ) ~2 Events / 9 Years CGRO ~2 Events / 2 Years INTEGRAL Mission COMPTEL Signal from SN1991T (3σ) (13 Mpc) -> 1.65 M of 56 Ni! Upper Limit for SN1998bu (11 Mpc) The 56 Ni Power Source: 0.5 M o of 56 Ni?? Which Model Flavor? W7 / HeD / DDT /

25 Novae

26 Novae Classical Novae: Accreting WD in Binary System Runaway H Burning with Nuclear Processing of Upper WD Layer (p process) Ejection of ~10-4 M o Issues: Burning Time Profile Fuel Composition and Mixing Ejected Mass Nuclear Reactions Paths

27 Nova Diagnostics with Nuclear Lines CO Nova (1 kpc; 0.8 M o ) O-Ne Nova (1 kpc; 1.2 M o ) Brief Annihilation Flash β Decay Continuum (before optical nova!) 22 Na Radioactivity (O-Ne Novae)

28 Nova Gamma-Ray Light Curves Need Sky Survey Optical Nova (=discovery) After Characteristic Gamma-Ray Signals Hernanz et al., No Nova Gamma-rays Seen Yet Iyudin et al M( 22 Na) < M Theory: M( 22 Na) < M

29 Nucleosynthesis from Massive Stars

30 Stellar Structure & its Evolution; SN Types mass coordinate-> mass-> RSG mass loss uncertainty -> SN subtype=? mass-> < The final My of a Star > Heger, Chieffi, Limongi, Woosley et al. metallicity-> Check Isotopic Production through Radioactivity courtesy Alex Heger mass->

31 Nucleosynthesis in CC-Supernova Models Shell-Structured Evolved Massive Star Gravitational Core Collapse Supernova Shock Wave Shock Region Explosive Nucleosynthesis 44 Ti Produced at r < 10 3 km from α-rich Freeze-Out, => Unique Probe (+Ni Isotopes) Proto-Neutron Star Neutrino Heating of Shock Region from Inside

32 Detection of 44 Ti Gamma-Rays from Cas A COMPTEL Imaging Compton Telescope Iyudin et al. 1994, 1997; Schönfelder et al Cas MeV: 44 Ti (T 1/2 ~59y) Point Source in 44 Ti Line Band (1157 kev) Spectrum from this Region shows 44 Ti Line Flux Uncertain from Systematics ( ph cm -2 s -1 )

33 More Cas A 44 Ti Results since COMPTEL Discovery BeppoSAX Vink et al Detection of 68,78 kev Lines; Continuum? Flux 2.6 (±0.4 ±0.5) 10-5 cm -2 s -1 INTEGRAL / IBIS Vink et al Detection at 68 kev (not 78 kev line) Flux 2.3± cm -2 s -1 Consistent with BeppoSAX INTEGRAL / SPI Vink 2005 No Detection, 3σ limit cm -2 s -1 OK if Line Broadening >7800 km s -1 INTEGRAL / IBIS BeppoSax Significance Map kev (v±7800 km s -1 )

34 Summary: 44 Ti from Cas A τ =89y, EC 44 Ti τ = 5.4 h, β + 44 Sc 44 Ca -> 44 Ti Ejected Mass ~ M o

35 Normal Core Collapse Supernovae (?) Consistency Check: Cas A vs. what we know about 44 Ti 44 Ti from SAD/Models/SN1987A/γ-Rays, vs. 56 Ni Only Non-Spherical Models Reproduce Observed Ratios Sky Regions with Most Massive Stars are 44 Ti Source-Free 44 Ti Survey (COMPTEL) Non-spherical explosions?? (->GRB) Need Event Statistics, 44 Ti Spectra

36 Stellar Structure & its Evolution; Burning Shells More Nucleosynthesis throughout the Star, + Explosive Nucleosynthesis 26 Al, 60 Fe

37 Hints from Presolar Grains Isotopic Ratios in C,N,Si, -> Source Type of Presolar Grain AGB Stars Supernovae Novae Amari, Nittler, Hoppe, Zinner, et al. 26 Al Found in ~ALL Candidate Sources

38 Candidate Sources of 26 Al p-rich Environment -> H Burning Seed Nuclei (Ne-Na group or Mg) Ejection of Nuclear Ashes (Wind, Explosion) Core-Collapse Collapse Supernovae Explosive Burning in O-Ne Shell, Triggered by SN Shock Wave Ejection of Pre-SN 26 Al and Explosive-Burning 26 Al Massive Stars in their Wolf-Rayet Phase Core H-Burning -> 26 Al Production During ~10 5 y MS Phase WR Phase Mixing & Stellar Wind -> Ejection into ISM AGB Stars (M>4M ) H Shell Burning, Fresh Seed Nuclei from He Pockets Ejection Through Thermal Pulses, >> 26 Al Decay Time Novae H Accretion onto White Dwarf Explosive H Burning with Seed Nuclei Admixture

39 The Sky Glows at 1809 kev: 26 Al Sco-Cen Cen? Auriga/α Per? Cygnus Inner-Galaxy Ridge Carina Vela Orion Eridanus Complete CGRO Mission (9y) (Plüschke et al. 2001)

40 Candidate Sources of 26 Al p-rich Environment -> H Burning Seed Nuclei (Ne-Na group or Mg) Ejection of Nuclear Ashes (Wind, Explosion) Core-Collapse Collapse Supernovae Explosive Burning in O-Ne Shell, Triggered by SN Shock Wave Ejection of Pre-SN 26 Al and Explosive-Burning 26 Al Massive Stars in their Wolf-Rayet Phase Core H-Burning -> 26 Al Production During ~10 5 y MS Phase WR Phase Mixing & Stellar Wind -> Ejection into ISM AGB Stars (M>4M ) H Shell Burning, Fresh Seed Nuclei from He Pockets Ejection Through Thermal Pulses, >> 26 Al Decay Time Novae H Accretion onto White Dwarf Explosive H Burning with Seed Nuclei Admixture

41 26 Al from Massive Stars Different Production Regions: H Convective Core C (Ne/C) convective Shell (when the star is in shell Si burning) Explosive Ne burning H rich mantle He core CO core Si burning shell He core CO core C conv shell explosive burning Central H burning Fe core C conv shell Ejected by the stellar wind Ejected by the explosion Ejected by the explosion Relative Contributions Depend on Stellar Model -> WR stars, SNe -> Limongi & Chieffi 2006

42 26 Al Synthesis Models (Wind and SN Ejection) How Much is Seen? -> Are These Models OK?

43 60 Fe: Cosmic SN Debris Detected on Earth! Pacific Ocean Crust Analysis Slow, Fe-rich Growth (2mm/My) Dating with CR-Produced 10 Be AMS Atom Counting Nearby SN 2.8 My ago? Knie et al update (NIC 2006): Atlantic (Faster-Growing) Crust (Knie, Korschinek et al. 2006) or rather 2 My ago

44 Producing 60 Fe: n Capture

45 Producing 60 Fe: n Capture Successive n Capture on Fe Isotopes ( 56 Fe) 59 Fe β Decay Rate Generates a Leak

46 Producing 60 Fe: n Capture (γ,n)-reactions Destroy 60 Fe Quickly in Hot Regions

47 Producing 60 Fe: n Capture Successive n Capture on Fe Isotopes ( 56 Fe) 59 Fe β Decay Rate Generates a Leak Lessons for the Origin of Heavy Elements / r-process

48 60 Fe Production in Stars No Production during ANY Central-Burning Phase Need Convection plus n Source Courtesy M. Limongi, Nov 2005 Explosive-Burning Contributions Negligable Ejection by Supernova Explosion

49 60 Fe Detections (?) from the Galaxy with RHESSI & SPI/INTEGRAL RHESSI 2.6 σ Detection Smith 2004 I=0.63 ± ph cm -2 s -1 Smith 2005 SPI 3 σ Detection I=0.4 ± ph cm -2 s -1 Harris et al Wang et al., in prep.

50 60 Fe from Massive Stars: Observational Limits vs. Theory Improved Models Agree with Limits on 60 Fe/ 26 Al Gamma-Ray Intensity Ratio But: Uncertainties are Large Marginal Detections -> Ratio <0.3 Revised Yields Had Led to Higher Predicted Ratios ~1.0 Revised Stellar Models Again Reduced Predicted Ratios Assessments Needed: Stellar Models Nuclear Physics Gamma-Ray 60 Fe Signal

51 Distributed Nucleosynthesis in the Galaxy 26 Al e +

52 The 26 Al Sky: Massive-Star Activity in the Galaxy Sco-Cen Cen? Auriga/α Per? Cygnus Inner-Galaxy Ridge Carina Vela Orion Eridanus Complete CGRO Mission (Plüschke et al. 2001)

53 Time Domains of Galactic Nucleosynthesis First Stars First Type Ia Supernovae τ mixing(ism)? T G [Gy] τ delay? τ disk? Star Forming History in Solar Vicinity Chiappini et al Galactic Disk Formation.?? Collisions with other Galaxies?.? We see t coll,i? Latest Star Forming Episode τ SF? Latest Star Forming Episode Current Pop I Stars Form SNR,Pulsars Ages ky 26 Al Ages My HII Regions Ages 0 5 My a highly fragmented and biased set of nucleosynthesis tracers SNe Currently-Visible SNR [My]

54 Nucleosynthesis Sources in the Galaxy Star Forming Regions in GMClouds along Spiral Arms Clustered Source Regions, Local Disks/Belts Russeil 2003 Blaauw1964 The Galaxy Nearby Stellar Groups

55 Massive-Star Groups: E kin and New Nuclei Model Ingredients: Stellar Evolution Stellar Wind Model(s) Initial Mass Function Nucleosynthesis Yields WR, SN Sample Statistics Analysis Model Predictions: 26 Al Gamma-Ray Luminosity (t) EUV Luminosity (t) Kinetic-Energy Ejection (t) S. Plüschke, PhD Thesis, TUM > Plüschke et al., 2001; Cerviño et al > Injection of ISM Turbulence and Radioactivity at 3 10 My

56 Massive Stars in Orion and 26 Al: ISM Dynamics Dust Emisssion (IRAS) and HI Trace Neutral Gas Around the Eridanus Bubble, X-Ray Emission Traces Hot Gas Inside the Cavity Massive Stars of the OB1 Association Eject 26 Al Radioactivity into the Eridanus Cavity (COMPTEL, Diehl et al. 2002) l=210 Orion A,B Eridanus Bubble Orion OB1 l=200 l=185

57 High-Resolution Gamma-Ray Spectroscopy in Space: SPI on INTEGRAL Cosmic-Ray Bombardement -> Crystal Degradation ~2% per Orbit, ~20% in 6 Months (@1 MeV) Annealing ~130 hrs at 105 o C, few hrs at 90K E Resolution (FWHM)[keV] 12 Feb Jul Nov Jun Jan Jun 2005 FWHM ~ *rev INTEGRAL Orbit No.

58 26 Al Line Spectroscopy (inner Galaxy) (before 2002) -> > ISM!?! HEAO-C Satellite Ge Detector 26 Al Line Discovery (5σ) Line Width ~Instrumental (<3 kev) Mayoney et al., 1982, 1984 GRIS Balloone-Borne Ge Detector 26 Al Line Measurement (7σ) Line Width >Instrumental, Intrinsic Width 5.4 kev ( 540 km s -1 over 10 6 years!) Naya et al GRIS (Naya 1996)

59 26 Al Line Shape from the Inner Galaxy -> Diehl et al., A&A 2006 Data: Orbits (1.5y) 16 Ms 4Ms at GC Exposure Map [Km/sec] The 26 Al Line is Narrow (~instrumental width) SPI: kev, <2.8 kev ISM velocities km s -1 GRIS

60 Nucleosynthesis in the Current Galaxy: 26 Al 26 Al Reflects Sources of Nucleosynthesis (τ~10 6 y) COMPTEL Imaging -> Massive Stars are Dominating Sources COMPTEL Decay in ISM Large Cavities -> narrow line -> broad line ~400 km/s(?) SPI ~120 km/s SPI Young Clusters -> broad line INTEGRAL/SPI Task: Spectroscopy for 26 Al Source Regions

61 Galactic Rotation and the 26 Al Line -> Diehl et al., Nature o < l < +40 o (-0.14 ±0.31 kev) -10 o < l < +10 o Galactic Rotation Affects the Line Centroid ~as Expected Consolidation: These sources are NOT Localized Basis for GALACTIC 26 Al Amount Determination using geometrical / tracer models Measurements of 26 Al Mass in Galaxy = 2.8 (±0.8) M cc-sn Rate = 1.9 (± 1.1) per Century [km s -1 ] o < l < -10 o (+0.44±0.24 kev)

62 Galactic Supernovae from Massive Stars

63 Annihilation of Positrons in the Galaxy 511 kev Line Emission Imaging with SPI: Extended, ~bulge-like Emission (δl~8 o,δb~8 o ) No/Weak Disk Emission Seen; No Fountain +20 e+ annihilation line: kev; MaxEnt Strong et al INTEGRAL / SPI 511 kev Skymap Richardson-Lucy, Smoothed Knödlseder et al. 2004

64 Positron Annihilation Annihilation rate versus Temperature charge exchange Annihilation Rate Depends on ISM Phase y Radiative capture direct annihilation with H e - Gamma-Ray Signature: Line + Continuum Positronium Atom: Singlet State 1 S 0 / Para-Positronium 2h (511 kev) Triplet State 3 S 1 / Ortho-Positronium 3h (<511 kev) Direct Annihilation: e - + e + 2h (511 kev)

65 Annihilation Conditions: Which ISM Phase Diagnostics: 511 kev Line Shape ; Line/Continuum Ratio Warm Partly-Ionized ISM is Dominating Annihilation Environment No Narrowing (Grain Contribution) Needed Jean et al Churazov et al ionized ionized F3γ/F2γ for fully ionized plasma

66 Sources of Positrons Nucleosynthesis A X Z 1 Y + e + e e.g. 56 Ni(β + ), 44 Ti(β + ), 26 Al(β + ), 22 Na(β + ), 13 N(β + ), 14 O(β + ), 15 O(β + ), 18 F(β + ) A Z + Cosmic-Ray Nuclear Reactions e.g. 12 C(p,pn) 11 C(β + ),or 16 O(p,α) 13 N(β + ) Pion Production Pair Production Hot (=Pair) Plasma Strong Magnetic Fields Accreting Binaries, Pulsars p + p π + + X π + + μ + + e γ+γ e + +e γ+β e + +e β +, EC μ p + e + μ α β - ( τ = 2,6 10 ( τ = 2, s) s)

67 Positron Budget and Annihilation Gamma-Ray Flux Gamma-Ray Observations 511 kev Line Flux from Galactic Bulge: I=1.03 ± ph cm -2 s kev Line Flux from Galactic Disk: I=0.7 ± ph cm -2 s -1 Ps Continuum Fluxes Consistent with 511 kev Line (fract ps-annih =0.92 ±0.09) Bulge Brightness > Disk Brightness, but total I disk ~3 ± ph cm -2 s -1 Nucleosynthesis 26 Al e + Production: I ~ ph cm -2 s -1 SNIa e + Production: I ~ ph cm -2 s -1 cc-sn e + Production: I ~ ph cm -2 s -1 Novae Others Binaries? Pulsars? Dark-Matter Annihilations? small/negligable Positron Production in Galaxy is Sufficient to Explain I γ Morphology!?!

68 Annihilation of Positrons in the Galaxy 511 kev Line Emission Imaging with SPI: Extended, ~bulge-like Emission (δl~8 o,δb~8 o ) No/Weak Disk Emission Seen; No Fountain -> Not from Young Stars (Minor Contribution) Old stellar population! Dark-Matter Annihilations? e+ annihilation line: kev; MaxEnt Strong et al INTEGRAL / SPI 511 kev Skymap Richardson-Lucy, Smoothed Knödlseder et al. 2004

69 Sources of Positrons and Annihilation Sites -> Prantzos 2005 Could e + be transported from disk to central region of Galaxy? Large-scale transport in poloidal halo magnetic field after escape from turbulent disk and CR halo fields SPI/INTEGRAL 511 kev (Knödlseder et al. 2005) Han 2001 Poloidal Irregular Toroidal

70 What Next?

71 The MeV Sensitivity Gap and Potential Sources 26 Al 511 kev, G.C. inner Galaxy CasA Crab COMPTEL 44 Ti x 0.1 Nova@10kpc C,O:ISM SN87a mcrab x 0.01 SN Ia 56 80Mpc CasA

72 Future Goals for γ-ray Line Astronomy adapted from S. Boggs, 2003 by R. Diehl, 2005 Gamma-Ray Imager Narrow Line (10 6 s) Advanced Compton Telescope

73 A "Deep Nucleosynthesis Probe" Gamma-Ray Lens <10-6 ph cm -2 s -1 Sensitivity ~arcmin field-of-view E/ΔE~500 to lens spacecraft plastic scintillator (ACS) Ge stack PA BGO shield cryocooler small tower detector spacecraft

74 Gamma-Ray Sky Exploration Mission Next-Generation Compton Telescope ("ACT") Wide Field-of-View Sensitivity ~10-6 ph cm -2 s -1 Ge Strip Detector Si Block Detectors LiXe Detector Fast Scintillator

75 Astrophysics with Gamma-Ray Lines: Nucleosynthesis Sources in the Galaxy Spectroscopy of 56 Ni (SNIa) and 44 Ti (cc-sn) Decays -> Clarify Key Supernova Aspects Calibration of 56 Ni Mass (independent from E conversion models) 3D Effects in cc SNe ( 44 Ti Ejection) Diffuse Radioactivities -> Diagnostic Tool for Massive-Star Nucleosynthesis 26 Al is a Galaxy-Wide Reflection of Massive Stars -> 2.8 M o, 1.9 SN/100y 26 Al is a ISM Diagnostic on Nucleosynthesis Ejecta Feedback 60 Fe Nucleosynthesis Yields are ~Consistent with (UPDATED) Expectation: Nuclear-Physics Clarifications / Improved Gamma-Ray Constraints Needed e + Annihilation Emission Puzzle Line Characteristics Reflect Annihilation in Warm, Partly-Ionized ISM Emission is Concentrated in Bulge, Disk Sources (SN,N) are Barely Seen: Dark Matter Annihilation, or e + Propagation on Large Scales? Future Instrumentation Remains a Challenge Money & Technology

76 That's it. Thank you! back to more winter sports