Aldo Morselli INFN Roma Tor Vergata 6 Nov 2012

Transcription

1 The Quest for Dark Matter Signals and the gamma-ray sky: the low energy window Aldo Morselli INFN Roma Tor Vergata 6 Nov 2012 Cahill Center for Astronomy and Astrophysics Calteck 1!

2 Past decades saw precision studies of 5 % of our Universe -> Discovery of the Standard Model The LHC is delivering data We are just at the beginning of exploring 95 % of the Universe exciting prospects R.-D. Heuer, CERN 36th International Conference on High Energy Physics ICHEP2012 Closing Talk 2!

3 Cosmic rays: about 10 Myears in the Galaxy (6-7 g/cm2) Source further acceleration? Cosmic Rays creation acceleration injection Propagation Indirect, Direct and Accellerator Searches for Dark Matter " Modulation " Space experiments ~ 400 km Atmosphere 40 km 23 Xo High Montain Detectors Direct detection Balloons ~ 40 km ~3 g/cm 2 residual atmosphere Extensive Air Shower Detectors Particle Astrophysics Experiments Cherencov Detectors Particle Accelerators Underground, Under-ice, Underwater 3!

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5 Neutralino WIMPs Assume present in the galactic halo! is its own antiparticle => can annihilate in galactic halo! producing gamma-rays, antiprotons, positrons.! Antimatter not produced in large quantities through standard processes! (secondary production through p + p --> anti p + X)! So, any extra contribution from exotic sources ( annihilation) is an! interesting signature! ie: --> anti p + X! Produced from (e. g.) --> q / g / gauge boson / Higgs boson and! subsequent decay and/ or hadronisation.! 5!

6 Antiproton/proton ratio 1997 Caprice coll. Astrophysics Journal, 487, 415, 1997! 6!

7 MASS Matter Antimatter Space Spectrometer 5 September !

8 8!

9 MASS 89 flight 9!

10 MASS 89 flight 10!

11 MASS 89 11!

12 PAMELA Payload for Antimatter Matter Exploration and Light Nuclei Astrophysics In orbit on June 15, 2006, on board of the DK1 satellite by a Soyuz rocket from the Bajkonour launch site. First switch-on on June From July 11 Pamela is in continuous data taking mode 12!

13 ~ 6 years from PAMELA launch Launched in orbit on June 15, 2006, on board of the DK1 satellite by a Soyuz rocket from the Bajkonour cosmodrom. 13!

14 Antiproton-to-proton ratio Overall agreement with pure secondary calculation Adriani et al. - PRL 105 (2010) !

15 Positron fraction Adriani et al., Nature 458 (2009) 607 Adriani et al., AP 34 (2010) 1 (new results) Low energy charge-dependent solar modulation High energy (quite robust) evidence of positron excess above 10GeV 15!

16 Happy 4 th Birthday Fermi!! 11 June !

17 Fermi Electron + Positron spectrum Extended Energy Range (7 GeV - 1 TeV) One year statistics (8M evts) Fermi LAT Coll. Physical Review D, Aldo 82 Morselli, INFN (2010) Roma Tor [arxiv: ] Vergata! 17!

18 Leptophilic Models here we assume a democratic dark matter pairannihilation branching ratio into each charged lepton species: 1/3 into e+e-, 1/3 into µ+ µ- and 1/3 into Here too antiprotons are not produced in dark matter pair annihilation. Astrp Phys.32 (2009) 140 [arxiv: ] 18!

19 Pulsars 1. On purely energetic grounds they work (relatively large efficiency) 2. On the basis of the spectrum, it is not clear 1. The spectra of PWN show relatively flat spectra of pairs at Low energies but we do not understand what it is 2. The general spectra (acceleration at the termination shock) are too steep The biggest problem is that of escape of particles from the pulsar 1. Even if acceleration works, pairs have to survive losses 2. And in order to escape they have to cross other two shocks New Fermi data on pulsars will help to constrain the pulsar models 19!

20 Cosmic Ray Electrons Anisotropy! No#anisotropy,map! the levels of anisotropy expected for Geminga-like and Monogem-like sources (i.e. sources with similar distances and ages) seem to be higher than the scale of anisotropies excluded by the results However, it is worth to point out that the model results are affected by large uncertainties related to the choice of the free parameters Flight!data!sky!map! Distribu8on!of!significance,! fi<ed!by!a!gaussian! Significance!map! Fermi Coll. Physical Review D 82, (2010) [arxiv: ] 20!

21 electron + positron expected anisotropy in the directions of Monogem and Vela Fermi/LAT ULs! Vela" Monogem! Fermi Coll. Physical Review D 82, (2010) [arxiv: ] 21!

22 What if we randomly vary the pulsar parameters relevant for e+e- production? (injection spectrum, e+e- production efficiency, PWN trapping time) Under reasonable assumptions, electron/positron emission from pulsars offers a viable interpretation of Fermi CRE data which is also consistent with the HESS and Pamela results. D.Grasso et al. Astropart. Phys. 32 (2009), pp.140 [arxiv: ] 22!

23 Geomagnetic field + Earth shadow = directions from which only electrons or only positrons are allowed events arriving from West: e + allowed, e - blocked For!some!direc8ons,!e - or!e + forbidden! Pure!e +!region!looking!west!and!pure!e A!region!looking!East! Regions!vary!with!par8cle!energy!and!spacecraF!posi8on! events arriving from East: e - allowed, e + blocked To!determine!regions,!use!code!by!Don!Smart!and!Peggy!Shea!(numerically!traces! trajectory!in!geomagne8c!field)! Using!Interna8onal!Geomagne8c!Reference!Field!for!the!2010!epoch! 23!

24 Positron Fraction The Fermi-LAT has measured the cosmic-ray positron and electron spectra separately, between 20 and 130 GeV, using the Earth's magnetic field as a charge discriminator Two independent methods of background subtraction produce consistent results The observed positron fraction is consistent with the one measured by PAMELA Differences between different experiments below few GeV s probably due to charge-sign-dependent modulation but still under study Fermi Coll., PRL, 108 (2012) arxiv: !

25 Leptophilic Models here we assume a democratic dark matter pairannihilation branching ratio into each charged lepton species: 1/3 into e+e-, 1/3 into µ+ µ- and 1/3 into Here too antiprotons are not produced in dark matter pair annihilation. update of Astrp Phys.32 (2009) 140 [arxiv: ] Pamela + Fermi positrons 25!

26 Search Strategies Satellites: Low background and good source id, but low statistics Galactic center: Good statistics but source confusion/diffuse background Milky Way halo: Large statistics but diffuse background Spectral lines: No astrophysical uncertainties, good source id, but low statistics And electrons! and Anisotropies Galaxy Extra-galactic: clusters: Large statistics, but astrophysics,galactic Low background but diffuse background low statistics Pre-launch sensitivities published in Baltz et al., 2008, JCAP 0807:013 [astro-ph/ ]! 26!

27 Annihilation channels 27!

28 Differential yield for each annihilation channel WIMP mass=200gev! A.Cesarini, F.Fucito, A.Lionetto, A.Morselli, P.Ullio, Astroparticle Physics, 21, 267, 2004 [astro-ph/ ]! 28!

29 Differential yield for b bar neutralino mass A.Cesarini, F.Fucito, A.Lionetto, A.Morselli, P.Ullio, Astroparticle Physics, 21, , 2004 [astro-ph/ ]! 29!

30 Fermi Gamma-Ray Large Area Space Telescope Tracker 1.68 m! 84 cm! Grid Silicon Tracker tower! 18 planes of X Y silicon detectors + converters! 12 planes with 3% R.L. of W, 4 planes with 18% R.L! 2 planes without converters! DAQ Electronics ACD Anticoincidence Shield! Calorimeter Thermal Blanket ( 8.5 Rad.Length) 30!

31 How Fermi LAT detects gamma rays 4 x 4 array of identical towers with: Precision Si-strip tracker (TKR) With W converter foils Hodoscopic CsI calorimeter (CAL) DAQ and Power supply box " Incoming Conversion ( in e + /e - ) in W foils Incoming direction reconstruction by tracking the charged particles e + e - An anticoincidence detector around the telescope distinguishes gammarays from charged particles Energy measurement with e.m. calorimeter 31!

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34 Elements of a pair-conversion telescope photons materialize into matter-antimatter pairs: E --> m e +c 2 + m e -c 2 electron and positron carry information about the direction, energy and polarization of the -ray (energy measurement) 34!

35 Elements of a pair-conversion telescope (more realistic scheme) photons materialize into matter-antimatter pairs: E --> m e +c 2 + m e -c 2 electron and positron carry information about the direction, energy and polarization of the -ray (energy measurement) 35!

36 6 projected angular distribution ( degrees) E(GeV) 0.15Xo(deg) 0.07Xo(deg) 0.05Xo(deg) projected angular distribution ( degrees) Multiple Scattering 0.15Xo(deg) 0.07Xo(deg) 0.05Xo(deg) E(GeV) E(GeV)! 36!

37 Multiple Scattering 50 37!

38 Fermi Instrument Response Function 38!

39 Fermi Instrument Response Function 39!

40 The Fermi LAT 2FGL Source Catalog August 4, 2008, to July 31, MeV to 100 GeV energy range 1873 sources 1095 AGN s 589 unidentified Fermi Coll. arxiv: !

41 The Fermi LAT 2FGL Inner Galactic Region August 4, 2008, to July 31, MeV to 100 GeV energy range Fermi Coll. ApJS (2012) 199, 31 arxiv: !

42 Spectrum (E> 400 MeV, 7 x7 region centered on the Galactic Center analyzed with binned likelihood analysis ) data (stat. error) preliminary best diffuse model and isotropic emission! 12 Fermi 1 year catalog sources V.Vitale, A.M. for the Fermi Coll. NIM A630 (2011) !

43 GC Residuals 7 x7 region centered on the Galactic Center 11 months of data, E >400 MeV, front-converting events analyzed with binned likelihood analysis )"! The systematic uncertainty of the effective area (blue area) of the LAT is ~10% at 100 MeV, decreasing to 5% at 560 MeV and increasing to 20% at 10 GeV! V.Vitale, A.M. for the Fermi Coll. NIM A630 (2011) !

44 DM in the galactic center? arxiv: ! 44!

45 Milky Way Dark Matter Profiles All profiles are normalized to the local density 0.3 GeV cm 3 at the Sun s location r 8.5 kpc A.Lapi et al. arxiv: ! 45!

46 Different spatial behaviour for decaying or annihilating dark matter The angular profile of the gamma-ray signal is shown, as function of the angle to the centre of the galaxy for a Navarro-Frenk-White (NFW) halo distribution for decaying DM, solid (red) line, compared to the case of self-annihilating DM, dashed (blue) line 46!

47 Galactic-Centre Gamma Rays in CMSSM Dark Matter Scenarios A 0 =0 µ>0 NFW profile" m =400 GeV FERMI! constraints" A 0 =0 µ>0 Einasto profile" m =400 GeV FERMI! constraints" m =300 GeV m =300 GeV WMAP" allowed region" WMAP" allowed region" The constraints due to the absences of charginos and the Higgs boson at LEP are also shown, as black dashed and red dot-dashed lines, respectively. Regions excluded by the requirements of electroweak symmetry breaking and a neutral LSP are shaded dark pink and brown, respectively. The green region is excluded by b sγ, and the pink region is favoured by the supersymmetric interpretation of the discrepancy between the Standard Model calculation and the experimental measurement of g μ 2 within 1 and 2 standard deviations (dashed and solid lines, respectively)! Ellis et al., arxiv: !

48 Gamma-light scheme 40+1 x-y planes 100 µm pitch each ~0.025 X 0 AC Tot~ 1 X cm height of a plane 1.3 cm 2 Xo Calorimiter 50 cm 50 cm 9.5 cm 100 µm pitch Compton'sca+ering'and'pair'produc2on'telescope' 48!

49 ESA'Call'for'Small'Missions:'June,'2012' Gamma-light payload Power~ 400 W Weight~600 Kg 49!

50 GAMMA-LIGHT satellite launch configurations for the PSLV and VEGA a companion satellite similar to G-LIGHT can be accomodated. 50!

51 Gamma-light Participants INAF Italian Institute of Astrophysics (INAF), Italy! INFN Italian Institute of Nuclear Physics, Italy! ASDC ASI Science Data Center, Italy! SRC PAS Space Research Center of Polish Academy of Sciences, Poland! NCAC Nicolaus Copernicus Astronomical Center, Warsaw, Poland! UBA University of Barcelona, Spain! DTU Space, Denmark! UIB University of Bergen, Norway! TOV University of Rome Tor Vergata, Italy! TUR University of Turin, Italy! YAL Yale University, USA! SAP University of Rome "La Sapienza, Italy! IFT-UAM Universidad Autonoma de Madrid, Spain! USAL University of Salamanca, Spain! TRI University of Trieste, Italy! ENEA, Italy! 51!

52 G-LIGHT Simulation Compton interaction of a 10 MeV photon producing a low-energy single-track electron, and depositing energy in the Calorimeter for a 30 0 incidence 52!

53 Gamma-light Simulation 53!

54 Effective area Fermi LAT! ( Front + Back)! Fermi LAT! ( Front)! GAMMA-LIGHT! 30 0! AGILE! 30 0! COMPTEL Kalman reconstruction, assumed bkg rejection eff !

55 PSF (68% containment radius) AGILE! 30 0! GAMMA-LIGHT! 30 0! Fermi LAT! ( Front + Back)! Fermi LAT! front P7v6! 55!

56 AGILE! Fermi LAT! ( Front)! GAMMA-LIGHT! Fermi LAT! ( Front+Back)! Flux Sensitivity 56!

57 Flux Sensitivity AGILE! GAMMA-LIGHT! Fermi LAT! ( Front)! Fermi LAT! ( Front+Back)! 57!

58 Astrophysics Objectives of GAMMA-LIGHT 1. Search of Dark Matter gamma-ray signatures in the Galaxy and in particular in the Galactic Center region; 2. Resolving the Galactic Center region in gamma-rays: the central BH region, GeV and TeV sources, nebulae, compact sources, SNRs; 3. Resolving the diffuse emission in the Galactic plane, relation with cosmic-ray propagation, star forming regions in the Galactic plane; extending the cosmic-ray propagation and emission properties of the "Fermi bubbles" to the lowest energies below 100 MeV; 4. Resolving spatially and spectrally SNRs and addressing the origin and propagation of cosmic- rays; 5. Polarization studies of gamma-ray sources; 58!

59 Astrophysics Objectives of GAMMA-LIGHT (cont.) 6. Detection of soft gamma-ray pulsars in the range MeV, and pulsar wind nebulae studies; 7. Detection of compact objects, microquasars, relativistic jets in the range 10 MeV - 1 GeV resolving the issue of hadronic vs. leptonic jets for a variety of sources (e.g., Cyg X-3); 8. Detection and localization of transients and exotic sources with much improved sensitivity;detection of Crab Nebula gammaray flares with excellent sensitivity down to 10 MeV; 9. Blazar studies down to 10 MeV, excellent positioning resolving source confusion; 10. GRB excellent capability in the range 10 MeV - 5 GeV; sub-millisecond timing capability in the range MeV. 59!

60 Extragalactic Sources, Blazars, MeV Blazars Multi-epoch SEDs of the FSRQ 3C454.3 G-LIGHT will allow us to investigate daily (or sub-daily) SEDs during gamma-ray super- flares. The 5-sigma G-LIGHT differential sensitivity (purple line) is computed for an integration time of 48 hours 60!

61 SNRs and the Origin and Propagation of CRs Bremsstrahlung GAMMA-LIGHT! sensitivity! neutral pion decay gamma-ray spectrum of SNRs W44. The red curve shows the expected GAMMA-LIGHT sensitivity for a 1-year effective time integration. 61!

62 Earth Studies Objectives of GAMMA-LIGHT: Terrestrial Gamma-Ray Flashes Fermi GBM 12xNaI! GAMMA-LIGHT CAL! Fermi GBM! 2xBGO! AGILE! GAMMA-LIGHT TRK! RHESSI! 62!

63 Earth Studies Objectives of GAMMA-LIGHT: Terrestrial Gamma-Ray Flashes G-LIGHT will fill this observational gap and contribute to TGF science with the following points: 1) detection of Terrestrial Gamma-Ray Flashes (TGFs) with extended energy range and imaging capability obtained by a new strategy for Earth albedo background rejection; 2) correlating high-energy TGFs with local and global meteorological data, addressing local climate and Climate Change issues; 3) studying the impact of TGFs and "high-energy"-tgfs for the atmospheric chemistry and particle transport including gammaray and neutron generation and atmospheric propagation to the ground; 4) maintaining an updated TGF archive, available to ESA and meteorological institutions. 63!

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65 INFN and the Cherenkov Telescope Array,! The future in VHE gamma ray astrophysics: 65!

66 V Agile E*F(>E) [ TeV/cm 2 s] Agile, Fermi, Argo, Hawk: 1 year Magic, Hess, Veritas, CTA: 50h E Fermi Magic-II Argo Hawc Crab 10% Crab Hess/Veritas E Far universe Pulsars Fundamental physics CTA Cosmic rays 1% Crab at the knee E [GeV] 66! 66!

67 Future Experiments GAMMA-400, 100 MeV 3 TeV, an approved Russian -ray satellite. Planned launch Energy resolution (100 GeV) 1 %. Effective area 0.4 m2. Angular resolution (100 GeV) DAMPE: Satellite of similar performance. An approved Chinese -ray satellite. Planned launch HERD: Instrument on the planned Chinese Space Station. Energy resolution (100 GeV) 1 %. Effective area 1-2 m2. Angular resolution (100 GeV) Planned launch around !

68 Gamma !

69 thank you for the attention 69!