Special Topics in Nuclear and Particle Physics

Transcription

1 Special Topics in Nuclear and Particle Physics Astroparticle Physics Lecture 5 Gamma Rays & x-rays Sept. 22, 2015 Sun Kee Kim Seoul National University

2 Gamma ray astronomy gamma ray synchrotron radition compton scattering pi0 decay

3 Gamma ray astronomy 10 ev. x- 100 GeV 100 GeV air shower air shower Cherenkov telescope

4 High Energy Astrophysics Mission as a function of Energy MIRAX 2-100keV ( ) ASTROSAT keV (mid ) 15-45keV, 30MeV-30GeV AGILE ( ) GLAST Swift keV (2004-?) Suzaku keV ( ?) INTEGRAL 3keV-10MeV ( ?) GRANAT 2keV-100MeV ( ) Mir-Kvant 2-200keV ( ) 8keV-300GeV (fall ) Ground-base Atmospheric Cherenkov Telescope (ATC) Arrays: CELESTE, HEGRA, HESS, VERITAS (1995-?) ( ) (1999-?) 1986-present ~TeV-PeV 100 ev 300 GeV kev MeV GeV 1E+11

5 Chandra 0.1 ~ 10 kev

6 INTREGRAL HPGe detector 20 kev 8 MeV Spectrometer Coded mask + compton telescope (15 kev -10 MeV) Imager

7 Compton telescope 100keV ~ 10 MeV 2 1 cosφ = m e c ( E 2 1 E 1 )

8 GLAST/LAT Tracking by Silicon strip detector, CsI(Tl) crystal calorimeter 20 MeV 300 GeV > 8000 cm 2

9 Cherenkov Radiation Charged particle in medium(n) with v > c/n eimits EM radiation cosθ c = ct / n βct = 1 βn Threshold β > 1 n Threshold energy E = mc2 (STP) 1 β 2 mc 2 2δ E 21 MeV for electron, 4.3 GeV for muon photons for 400nm ~ 700nm ~220/cm water ~30/m air ~42 o water ~1.4 o air n = = 1+ δ β 2 = (1+ δ ) 2 1 2δ

10 Cherenkov Telescope for High Energy Gammy Ray Astronomy Particle shower ~ 10 km Cherenkov light ~ 120 m ~ 1 o Source position Intensity â shower energy Image orientation â shower direction Image shape â primary particle

11 Gamma rays -EM shower -electrons radiate C.R. -Shower is very narrow

12 Cherenkov Telescopes Status # Tel Mirror (m 2 ) F.o.V ( o ) Energy threshold(gev) MAGIC H.E.S.S. CANGAROO III Data taking 08/2004 Data taking 12/2003 Data taking 03/2004 Veritas Start 10/2006 Prototyp running ~ ~100

13 Galactic Center syst. error D. Horns, Phys. Lett. B 625, 225, 2005

14 H.E.S.S. Resolved Supernova-Remnants RX J Index ~ SNR Shock wave acceleration > 100 TeV

15 Gamma ray production in Sky synchrotron radiation P 2 2 ~ E B Bremsstrahung Inverse compton scattering pi0 decay matter antimatter annihilation MeV for e+e- annhil. Nuclear decay : gamma ray spectroscopy à identification of nuclei Dark matter annihilation

16 Sources of gamma rays in Sky Galactic sources Pulsars : synchrotron radiation SN remnants :synchrotron radiation, pi0 decays spectral gammas from heavy nuclei ex. SN1987A Ni-56 ( MeV) Accreting black hole Extragalactic sources AGN(Acrive galactic nuclei) quasars gamma ray bursters

17 Gamma Ray Bursters GRBs were first reported in 1973, based on observations by the Vela military satellites monitoring for nuclear explosions in verification of the Nuclear Test Ban Treaty. When these mysterious gamma-ray flashes were first detected, which did not come from Earth's direction, the first suspicion (quickly abandoned) was that they might be the product of an advanced extraterrestrial civilization. Compton Gamma Ray Observatory (CGRO) Interplanetary Network (IPN) Swift (2004) sec short pulse energy of solar mass in 10 sec ~ one GRB per day (observed) isotropic à extragalactic origin

18 What are they? violent SN explosion à hypernova signal of the birth of black hole? collisions of neutron stars with black holes cosmological origin?

19 X- ray production in Sky synchrotron radiation Bremsstrahung Inverse compton scattering thermal radiation P 3 ~ hν / kt e ν 1 P ~ e hν / kt for high energy P ~ν 2 for low energy Total radiation S = σt 4

20 Sources of X rays in Sky Galactic sources Pulsars : synchrotron radiation SN remnants :synchrotron radiation Binary starts - Accreting neutron star, white dwarf, black hole Extragalactic sources intergalactic hot gases AGN quasars gamma ray bursters coma cluster

21 The Crab Nebula (catalogue designations M 1, NGC 1952, Taurus A) supernova remnant in the constellation of Taurus First observed in 1731 by John Bevis, the remnant of a supernova that was recorded, as a star visible in daylight, by Chinese and Arab astronomers in 1054(SN1054). about 6,300 ly from Earth, the nebula has a diameter of 11 ly (3.4 pc) and is expanding at a rate of about 1,500 km/s. Pulsa at center (33 ms) neutron star

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23 Explosive X-Ray & Gamma-Ray Spectroscopy: Supernovae X-rays annihilation line Gamma-rays Chandra image + optical image Type Ia SN Cas A: flung-off companion to the exploded white companion

24 Active Galactic Nuclei (AGN) Galaxy with active nucleus strong emission from radio to x-ray, gamma rays outshines the host galaxy, from a very small volume ~ times solar luminosity quasars at large red shift à may be characteristics of a galaxy s early life? Doppler shift of visible and UV from the gas with speeds ~ 10,000 km/s ~ 10 8 solar mass black hole at the center of the galaxy? Seyfert galaxies, Radio galaxies, Quasars, Blazars

25 NGC 4258 is about 30 thousand light years across and 21 million light years away rad & yellow visible and IR blue : x-ray purple : radio

26 M87

27 TeV Review: Radiation Processes in X-Ray Binaries (BH/NS) & Quasars Corona ( K) Relativistic Jet (v~0.99c) (10 7 K) SSC, boosting ~TeV Accretion Disk (>10 6, >10 9 km) aournd ~10, >10 6 M Jet Cyg A X-Ray Binary flux = f bb + f cyc + f br + f syn + f ic + f ssc +f leptonic(e+e-) +f hadronic(pp(γγ), ) +