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Washington U. Bob Binns Jay Cummings Louis Geer Georgia deN olfo Paul Hink Martin Israel

Constraints on the GCR Source Derived from Isotopic Abundance Measurements. Washington U. Bob Binns Jay Cummings Louis Geer Georgia deN olfo Paul Hink Martin Israel Joseph Klarmann Kelly Lave David Lawrence. Caltech/JPL A.C. Cummings R.A. Leske R.A. Mewaldt E.C. Stone

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Washington U. Bob Binns Jay Cummings Louis Geer Georgia deN olfo Paul Hink Martin Israel

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  1. Constraints on the GCR Source Derived from Isotopic Abundance Measurements Washington U. Bob Binns Jay Cummings Louis Geer Georgia deNolfo Paul Hink Martin Israel Joseph Klarmann Kelly Lave David Lawrence Caltech/JPL A.C. Cummings R.A. Leske R.A. Mewaldt E.C. Stone M.E. Wiedenbeck NASA/Goddard L. M Barbier T. Bradt E.R. Christian G.A. deNolfo T. Hams J.T. Link J. W. Mitchell K. Sakai M. Sasaki T.T. Von Rosenvinge Mike Lijowski Jason Link Katharina Lodders Ryan Murphy Susan Niebur Brian Rauch Lauren Scott Stephanie Sposato John E. Ward U of Minnesota C.J. Waddington TIGER (2001-2003) ACE-CRIS (1997-Present) Super-TIGER (2012) Erice 2014-Bob Binns

  2. Outline • Talk I--Isotopes • Cosmic Ray Basics • Sources of GCRs? • Measurement Techniques and Instruments • UH Isotope Measurements on ACE • UH Element Measurements on TIGER, ACE, & SuperTIGER (Ryan Murphy’s talk) • First Ionization Potential or Refractory/Volatility nature of elements • Constraints placed on the cosmic-ray sources by low-E cosmic rays • 59NWhat is the time between nucleosynthesis and acceleration? • Other important Isotopes (esp. 22Ne)Normal ISM (SS composition) or a mix of material? • Talk 2—Elements • Element abundances--gas/dust components? • Recent -ray measurements of distributed emission • The OB association model of origin of GCRs • Properties of massive stars & OB associations • Conclusions Erice 2014-Bob Binns

  3. Origin in our Galaxy. 30 GeV proton in B~6mG has gyro radius ~0.5x10-5 pc (~1 au). Learn about cosmic-ray sources from elemental and isotopic composition. Extragalactic origin. 3x1021 eV proton in B~3mG has gyro radius ~1 Mpc. Andromeda galaxy is ~0.65 Mpc from Earth Erice 2014-Bob Binns

  4. Elemental Abundances in the Galactic Cosmic Radiation • Elements in the upper 2/3rds of the periodic table, are extremely rare compared to lighter elements. • They contain unique information not obtainable from light cosmic rays. • Measurement requires large instruments at the top of the atmosphere or in space for long exposure times.

  5. Objectives of Galactic Cosmic Ray Research • Determine the source(s) of cosmic rays • What material is accelerated? • What are the nucleosynthesis sites of the accelerated nuclei? • What are the accelerators? • Measure the elemental, isotopic, and energy spectra so that the source abundances can be determined • Determine what changes occur as the CRs propagate from their source to us at 1AU. • Nuclear interactions, Leakage from galaxy, Solar Modulation, Earth’s magnetic field (for Earth orbiting missions)

  6. Cosmic Ray Source? • Stellar atmosphere injection • Low First-Ionization-Potential (FIP) elements enhanced (as in the solar corona, Solar Wind and SEPs). • Casse & Goret 1978; Meyer 1985 • Fractionation of particles from Sun “probably results from a separation of ions and neutrals, which takes place between the photosphere and corona at temperatures of 6,000-10,000 K.” • Schmeltz et al 2012 • Interstellar gas/grains with enhanced grain source • Many low-FIP elements are refractory and most high-FIP elements are volatile • Refractory elements enhanced • Mass dependence for volatile elements • Epstein 1980; Bibring & Cesarsky 1981; Ellison et al. 1997; Meyer et al. 1997 • Acceleration of material in OB associations and their superbubbles by SN shocks and stellar winds • Wind material from massive stars • Montmerle 1979; Cezarsky & Montmerle 1981; Streitmatter et al. 1985; Bykov 1999; Parizot, et al. 2004; Higdon & Lingenfelter 2003, 2005, 2007; Meli & Biermann 2006; Prantzos 2012 • Supernova material N44 Superbubble Credit: Gemini Observatory/AURA

  7. Experiments aimed at measuring abundances of UHCRs Erice 2014-Bob Binns

  8. Techniques used for Low Energy, high-resolution GCR Composition Measurements (0.1-10GeV/nuc) (continued) • Low energy isotopic abundances • dE/dx-ETotal • ACE-CRIS-Stone et al. 1998 • IMP-7-Garcia-Munoz et al. 1979 • ISEE-3-Wiedenbeck & Greiner 1981; Mewaldt et al. 1980 • Voyager-Lukasiak et al. 1994; Webber et al. 1997 • Ulysees-Connell & Simpson 1997 • CRESS-DuVernois et al. 1996 • Multiple dE/dx measurement crucial for good resolution • Reject interactions in detector • Consistency requirement for “funny” events • dE/dx = kZ2/β2 • EKE = 0.5 mβ2

  9. Techniques used for Low Energy, high-resolution GCR Composition Measurements (0.1-10GeV/nuc) • Low energy elemental abundances • Multiple dE/dx-Cherenkov • HEAO-3 HNE (C3)-Binns et al. 1989 • dE/dx Ionization chambers • Cherenkov n=1.5 • Wire ionization hodoscope • Multiple dE/dx-Double Cherenkov • TIGER & SuperTIGER-Rauch et al. 2009 & Binns et al. 2014 • dE/dx (dL/dx) Plastic scintillator (dE/dx saturates) • Double refractive index Cherenkov (n=1.5, 1.04, 1.025) • Scintillating fiber hodoscope • Multiple Cherenkov • HEAO-3 (C2)-Engelmann et al. 1990 • Five Cherenkov counters (multiple refractive indices) • Flash tube hodoscope C0=a Z2 [1-1/(n02b2)] C1=b Z2 [1-1/(n12b2)] dE/dx=kZ2/b2 C1=k’Z2 [1-1/(n12b2)]

  10. Other composition experiments at higher energies • Magnet Experiments (Elements & Isotopes) • ISOMAX-Hams et al. 2004 • HEAT-Beach et al. 2001 • PAMELA-Adriani et al. 2013 • BESS • AMS-Aguilar et al. 2013 • Calorimeter experiments • ATIC—Panov et al. 2006 • CREAM-Yoon et al. 2011 • CALET-Torii et al. 2013

  11. The ACE-CRIS Experiment: Isotope Measurements

  12. The Cosmic Ray Isotope Spectrometer (CRIS) on ACE • Advanced Composition Explorer (ACE) satellite launched in August, 1997. • Still in orbit about the L1 Lagrange point between Earth and the Sun • Still sending back good element and isotope data on GCRs • No significant degradation in instrument performance 10 cm CRIS Erice 2014-Bob Binns

  13. Instrument Cross-section • Large geometrical factor of CRIS (~50 x previous instruments) • Excellent mass resolution enables precise identification of abundances. • Long time in orbit—nearly 17 years

  14. How do we derive source abundances from data? • CRIS concept is simple, but the DEVIL is in the details!! • Mass resolution • Angle Measurement • Theta correction to signals (achieved <0.1º angle resolution) • Require “good hodoscope” three consistent x,y coordinate pairs • For best resolution, use events that are near vertical (e.g.<25º to vertical); for Z>28, need all the particles we can get, so accept <60º • Reject interactions • Reject penetrating events--signal in the bottom anticoincidence detector • Require charge estimate consistency using different combinations of detectors for estimate • Require penetration to E3 or deeper so can apply consistency rqmt • Reject “dead layer” events (particles stopping within ~500 µm from surface on one side of wafer) & correct for nonlinearities in signal from silicon detectors • Reject particles exiting through the side of the stack using anticoincidence rings • Map actual thickness of all silicon detectors • Abundances at top-of-detector • Interaction corrections • Energy interval corrections • Source abundances • Propagate from instrument through heliosphere • Propagate back to the source Dead layers ~500mm thick 6 mm

  15. Crossplot of CRIS data

  16. Histogram of CRIS data Erice 2014-Bob Binns

  17. What questions can we address with composition measurements of heavy nuclei (Z>26)? What is the time between nucleosynthesis and acceleration? How do GCR isotope and element ratios compare with those from possible sources? Does the volatile (gas) or refractory (dust grains) nature of an element affect the composition of CRs? Do cosmic ray abundances depend on mass? Erice 2014-Bob Binns

  18. What is the time between nucleosynthesis and acceleration of GCRs? • Does a SN shock accelerate nuclei synthesized in that same SN? • Soutoul et al., 1978 radioactive isotopes that decay only by electron-capture can be used to measure the time between nucleosynthesis and acceleration. • 59Ni decays only by electron-capture with half-life 76,000yr in lab. • 59Ni + e- → 59Co + n • BUT, at cosmic-ray energies it is stripped of electrons, so is essentially stable. • If GCR are accelerated by the same SN in which the nuclei are synthesized, expect to see 59Ni in the GCR. • So what do we observe???? Erice 2014-Bob Binns

  19. GCR Nickel and Cobalt Histograms • So GCR source is ambient interstellar matter accelerated >105 years after nucleosynthesis • Corolary: Whatever the source of GCRs, there must be time between nucleosynthesis and acceleration for the 59Ni to decay • Constraint #1 Wiedenbeck, et al., ApJL, 523, L51 (1999)

  20. Mass Ratio • What fraction of mass-59 nuclei is expected to be synthesized as 59Ni in core-collapse SNe? • Note that Type-1a Sne are also copious producers of 59Co and 59Ni (Iwamoto et al. 1999) • However, Type 1a SNe • ~15% of total SN rate • ejecta spreads throughout the galaxy over time • Core-collapse SNe seed a high-metallicitysuperbubble environment, ready for acceleration by the relatively frequent, nearby SNe.

  21. Other Isotopes measured by ACE-CRIS Erice 2014-Bob Binns

  22. The cosmic-ray source composition differs from that of the Solar System. • The CRIS experiment, finds a 22Ne/20Ne source ratio relative to SS of 5.30.3 • Earlier experiments also found substantial enhancements (e.g. Ulysses, Voyager, CRRES, ISEE-3) • Best accepted explanation is that this might result from an admixture of WR wind material, rich in 22Ne, with normal ISM (with SS composition). (Montmerle, 1979; Cesarsky & Montmerle, 1981; Higdon & Lingenfelter 2003, 2005) Sample of local ISM today Galactic Cosmic-Ray Source Samples of the local interstellar medium (ISM) ~4.6 Gyr ago

  23. Time evolution of WR abundances Time evolution of mass Non- rotating star • Evolution of surface abundances (mass fraction) with stellar mass for 60M⊙ star (Meynet & Maeder, 2003) Rotating star Non-rotating Star Rotating Star 300 km/s at equator • Top curve—total mass; Bottom curve—convective core mass • 22Ne greatly enhanced during helium • burning through the -capture • reaction 14N(,)18F(e+,)18O(,)22Ne

  24. ACE-CRIS isotope ratios for Z≤28 Ne • Higdon and Lingenfelter (2003) • GCR 22Ne/20Ne ratio consistent with a source made of a mixture of ~82% SS composition and 18% wind outflow+ejecta from massive stars. • Superbubble/OB association origin of GCRs. • But, used Schaller et al. 1992 for massive star wind yield. More recent calculations (Hirshi, et al. 2005) show reduced 22Ne production. • Binns, et al (2005) • GCR abundances of a range of isotope and element ratios for Z≤28 nuclei are consistent with ~20% massive star outflow (Meynet & Maeder, 2003, 2005) mixed with ~80% normal ISM (SS composition). Fe Ni C/0 Si Mg

  25. Isotopes for Z>26

  26. Z>28 Nuclei • ACE-CRIS has provided the first, and only existing measurements of isotopic abundances of 29Cu, 30Zn, 31Ga, & 32Ge. • We see well resolved isotope peaks from 29Cu through 32Ge with sufficient statistics for a meaningful measurement. • Note “possible” 3-event peak at mass 67-- Electron capture isotope—lifetime 3.3d • If real, they have to be secondaries

  27. Ultra-heavy isotopes in context of previous lower-Z data • Note that the isotopic ratio error bars for new UH isotopes are statistical only. Constraint #2 New data are consistent with model, but also with solar system abundances. CR source must be able to produce isotope ratios that are “equivalent to” that obtained by mixing ~20% of MSO with ~80% of normal ISM. 27

  28. Summary of constraints imposed by isotope measurements • Isotopes measured by ACE-CRIS have provided two constraints for the source of GCRs • Constraint 1—The acceleration of GCRs must occur more than ~105 years after nucleosynthesis • Constraint 2—The abundances of the isotopic ratios measured must be “equivalent to” that obtained by mixing ~20% of massive star outflow material with ~80% of normal ISM (with SS abundances) Erice 2014-Bob Binns

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