1 / 87

Gamma ray astroparticle physics with GLAST

Gamma ray astroparticle physics with GLAST. a rotating black hole in an accretion disk. Binary system formed by a black hole and a companion star. A model of Gamma Ray Burst. PULSARS. Multiwavelength light curves of the seven pulsars detected by GRO.

diza
Télécharger la présentation

Gamma ray astroparticle physics with GLAST

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Gamma ray astroparticle physics with GLAST

  2. a rotating black hole in an accretion disk

  3. Binary system formed by a black hole and a companion star

  4. A model of Gamma Ray Burst

  5. PULSARS Multiwavelength light curves of the seven pulsars detected by GRO. Multiwavelength observations of more will severely constrain theoretical model for pulsar emission. High energy gamma-ray may dominate and can provide unique information on the map of pulsar magnetosphere and emission mechanism.

  6. Multiwavelenght observation of Mrk 501 in June 98 High state Low state R. Sambruna et al., RXTE and Hegra, astro-ph 0002215

  7. Energy versus time for X and Gamma ray detectors We need experiments in the 10 Mev- 100 GeV range MKH 501 astro-ph 0103200

  8. Energy versus time for X and Gamma ray detectors Aldo Morselli 7/01 http://www.roma2.infn.it/infn/agile/

  9. Sensitivity of g-ray detectors All sensitivities are at 5s. Cerenkov telescopes sensitivities (Veritas, MAGIC, Whipple, Hess, Celeste, Stacee, Hegra) are for 50 hours of observations. Large field of view detectors sensitivities (AGILE, GLAST, Milagro,ARGO are for 1 year of observation. Integral flux (photons cm-2 s-1 ) MAGIC sensitivity based on the availability of high efficiency PMT’s Aldo Morselli 01/01 http://www.roma2.infn.it/infn/agile/ Photon Energy (GeV)

  10. EGRET(Spark Chamber) VS. GLAST(Silicon Strip Detector) GLAST Large Area Telescope (2006-2015) EGRET on Compton GRO (1991-2000)

  11. Detector Technology: X-ray vs. Gamma-ray X-ray (0.5 - 10keV) Focusing possible Large effective area Excellent energy resolution Very low background Narrow view Gamma-ray(0.1-500GeV) No focusing possible Wide field of view Limited effective area Moderate energy resolution High background

  12. GLAST LAT Strength-Large Field of View- 200  bursts per year  prompt emission sampled to > 20 µs AGN flares > 2 mn  time profile + E/E  physics of jets and acceleration  bursts delayed emission

  13. GLAST LAT Strength- Continuous All-sky Monitoring -

  14. GLAST LAT Strength- New EGRET Catalog Every 2 days - All 3EG sources + ~ 80 new in 2 days  periodicity searches (pulsars, X-ray binaries)  pulsar beam, emission vs. luminosity, age, B In scanning mode, the LAT will achieve after one day sensitivity sufficient to detect (5s) the weakest EGRET sources

  15. One year All-Sky Survey Simulation, Eg > 100 MeV All-sky intensity map based on five years EGRET data. All-sky intensity map from a GLAST one year survey, based on the extrapolation of the number of sources versus sensitivity of EGRET

  16. Pulsars • Tutte le pulsars nei raggi gamma hanno un cut-off ad alta energia • Il Polar Gap model predice un ripido cut-off • Outer gap model predice un cut-off più graduale • I dati di EGRET non consentono di discriminare fra i diversi modelli

  17. (1a) E=w1 e+ g J g e- Flux absorption due to the interaction with the infrared and microwave background g ray source Microwave and infrared background Earth if the center of mass energy is: photons interactions produce electron positron pairs E=w2

  18. (2a) e+ g J g e- E=w2 Flux absorption due to the interaction with the infrared and microwave background The cross section of the process gg -> e+e- is: where re is the classical radius of the electron and: E=w1 w1 and w1 are respectively the energies of the low and the high energies gamma ray and J is their angle of incidence.

  19. (3a) E=w1 e+ g J g e- E=w2 Flux absorption due to the interaction with the infrared and microwave background the ratio between the flux I(L) at a distance L from the source and the initial flux I can be written as: I(L)/Io=exp(-kg L) where kg is the absorption coefficient: that contains the cross section and the low energy photon distribution. For the microwave spectrum:

  20. (4a) Ratio between surviving flux and initial flux versus photon energies for two different distances due to the sum of the infrared and black-body background A.Morselli , INFN/AE-94/22

  21. (5a) Ratio between surviving flux and initial flux versus photon energies for two different distances (blow up) A.Morselli , INFN/AE-94/22

  22. Energy density of the extragalactic diffuse background radiation (6a) 12500 1250 125 12.5 1.25 0.125 Eg (TeV) 0.1 10 1 103 102 Characteristic absorbed g ray energy (TeV): l (mm) Hegra , astro/ph/9802308 E2 n(E) (ev/cm3) Near Infrared Far Infrared Average models Dust Starlight Energy (ev)

  23. (7a) Transparency of the Universe 105 p g e+ e- 104 PKS 0208 512 Distance (mpc) Z~1 ~ 2 1028 cm p gp +p- Z~0.53, 2C279 103 IR Z~0.03 ~2 1026 cm (Mrk521) 102 Super Cluster Virgo Cluster 60mly, 18mpc 101 Andromeda (700 kpc, 2.9Mly) radio 100 LMC (50 kpc, 179kly) g g e+ e- 10-1 Our galaxy 2.7 k Z~10-6 cm 10-2 10-3 1012 1016 1024 1010 1014 1018 1020 1022 E(eV) 10 TeV 100 GeV 1 PeV

  24. (8a) Flux absorption due to the interaction with the infrared and microwave background F(>E) cm-2 s-1 an example on 3C279: • fixed background • different values of the Hubble constant

  25. (6a) Cold Dark Matter Model CHDM z Cumulative Extragalactic Background light as a function of redshift Cold Dark Matter Model WCDM=0.9 , Wb=0.1 early era of galaxy formation ( 1< zf < 3 ) CHDM = Cold + Hot Dark Matter Model WCDM=0.6 , Wn=0.3 , Wb=0.1 late era of galaxy formation ( 0.2 < zf < 1 ) Macminn & Primac astro-ph 950432

  26. Gamma-ray spectrum from Markarian 501 corrected: spectrum after correction for the absorption in the infrared background Protheroe&Meyer astro-ph/ 9504032

  27. Transparency of the Universe Possible effect of Lorenz invariance violation

  28. Gamma-ray spectrum from Markarian 501 Possible effect of Lorenz invariance violation

  29. Counts / bin Energy (GeV) (* assumes no intrinsic source cutoff) Probing the era of Galaxy Formation Uncover the nature of Dark Matter Roll- offs in the g -ray spectra from AGN at large z probe the extra-galactic background light (EBL) over cosmological distances. A dominant factor in EBL models is the era of galaxy formation: AGN roll- offs may help distinguish models of galaxy formation, e. g., Cold Dark Matter vs. Hot Dark Matter-- 5 eV neutrino contributions, etc. See for example Macminn, D., and J. R. Primack, 1995, astro- ph/ 9504032.

  30. GRB000131 on 2000 January 31 observedby an international network of satellites (Ulysses, NEAR and Konus) with follow-up observations with the ESO Very Large Telescope The redshift Z measured from the afterglow is between 4.35 to 4.70 11,000 million light years , just 1,500 million years after the Big Bang

  31. A model of Gamma Ray Burst

  32. A model of Gamma Ray Burst

  33. First observation of a Gamma Ray Burst ?

  34. GRB studies with GLAST EGRET observed delayed GeV emission from the GRB of February 17, 1994, including a 20 GeV photon that arrived 80 minutes after the burst began. GLAST will make the definitive measurements of the high-energy behaviour of GRBs and GRB afterglows.

  35. GRB studies with GLAST (2) • Study of the initial impulsive phase: Dt< 1 ms • Expected detection rate (above 50 MeV): 50-100 yr -1 • Broad band spectral information: ~ 200 keV - 30 GeV • Rapid (few seconds) communication of GRB quicklook results • Single g angular resolution ~10 arcmin at high energies for good source localization.

  36. GLAST LAT Baring 1996 GLAST LAT GRB Location Accuracy Norris et al. 1998 GLAST and Gamma-Ray Bursts • The GLAST LAT will have: • Large ~2 sr field of view, so more detected bursts (~50–100/yr) • >10 EGRET effective area, so more photons per burst • 105 lower deadtime, so more detected prompt photons • Improved sensitivity E>10 GeV, for better locations and spectral range • ~5 better angular resolution, for arc-min GRB locations and better afterglow sensitivity • On-board computing for providing rapid GRB locations to afterglow observers • The GLAST LAT will not have: • Sensitivity <10 MeV, where there is the most knowledge of GRBs • Sensitivity outside its FoV • Fast trigger for weak bursts

  37. Instrument Requirements • GLAST - LAT will detect high-energy radiation from approximately 50 to 100 bursts per year (as compared to ~1 per year for EGRET) • GLAST will study the relationship between GeV emission and keV-MeV emission as a function of time during the burst. How does the high-energy spectral form and peak energy change with time? • Measurements of intrinsic burst spectra at these energies can constrain bulk Lorentz factors of relativistic fireball models and provide measurements of cutoffs due to absorption on the extragalactic background light at energies as low as 100 GeV for large redshifts.

  38. Instrument Requirements (2) • Ability to quickly recognize and localize GRBs • Field of view > 2 sr to monitor a substantial fraction of the sky at any time. • Spectral resolution better than 20%, especially at energies above 1 GeV, for sensitive spectral studies and searches for breaks • Sustain random photon rate of 10 kHz with less than 20% deadtime for determining correlations between low energy and high energy gamma-ray burst time structure • A goal in the ability to repoint the spacecraft autonomously in < 5 minutes • Single photon angular resolution approaching 10 arcminutes at high energies for good source localization. • Rapid (few seconds) notification of the burst and its position to the ground. • Burst notifications to be rapidly (few 10's of seconds) sent from the ground • Capability to simultaneously measure the low and high-energy components.

  39. (1q) Test of Quantum Gravity Candidate effect: c2 P2 = E2 ( 1+ f(E/EQG )) E=photon energy EQG =effective quantum gravity energy scale Deformed dispersion relation with function fmodel dependent function of E/EQG if E<< EQG series expansion is applicable c2 P2 = E2 ( 1+ a(E/EQG )+ O(E/EQG ) 2) v = dE/dP ~ c ( 1+ a(E/EQG )) vacuum as quantum-gravitational medium which respond differently to the propagation of particle of different energies. (analogous to propagation through an electromagnetic plasma) Medium fluctuation at a scale of the order of Lp~10-33 cm Dt = ~ a E/EQG D/c

  40. (2q) E1 E1 E2 E2 Test of Quantum Gravity Dt = ~ a E/EQG D/c E1 E1 E2 E2 Dti=0 Dtf=0 t=ti t=tf D ~ 2 1028 cm EQG ~1019 GeV c~3 1010 cm Dt(ms) ~ 60 DE(GeV) even at pulsars distance: D ~ 6 1021 cm Dt(ms) ~ 100 EQG ~1014 GeV

  41. Test of Quantum Gravity E = Photon energy EQG = Effective quantum gravity energy scale Deformed dispersion relation with function f model dependent function of E/EQG c2 P2 = E2 ( 1+ a(E/EQG )+ O(E/EQG ) 2) v = dE/dP ~ c ( 1+ a(E/EQG )) Vacuum as quantum-gravitational medium which respond differently to the propagation of particle of different energies. Medium fluctuation at a scale of the order of Lp~10-33 cm Dt = ~ a E/EQG D/c c2 P2 = E2 ( 1+ f(E/EQG )) D ~ 2 1028 cm EQG ~1019 GeV Dt(ms) ~ 60 DE(GeV)

  42. What is the Universe made of ? We know that there is dark matter, which is needed to explain the dynamics of stars in Galaxies and of galaxies in clusters. This dark matter does not interact with light, and we do not know wich particles is made of. The peripheral stars of the galaxy M63 rotate around the center so fast that they would fly away in space without the presence of additional mass inside the galaxy. This is indirect evidence for the presence of dark matter

  43. Dark matter problem The LSP can be a good candidate also for the solution of the Dark Matter Problem. Experimentally in spiral galaxies the ratio between the matter density and the Critical density W is : (t~1.5 g cm-2 ) Wlum ≤ 0.01 but from rotation curves must exist a galactic dark halo of mass at least: Whalo ≥ 0.1 from gravitational behavior of the galaxies in clusters the Universal mass density is : Whalo@ 0.2 ÷ 0.3 from structure formation theories and analyses of the CMB: Whalo ≥ 0. 3 but from big bang nucleosinthesis and analyses of the CMB the Barionic matter cannot be more then: 0. 03≤WB ≤ 0. 05 (astro-ph/0106035) So the best candidate seems to be a Weakly Interacting Massive Particles (WIMP), but neutrinos with mass less then 30 eV do not reproduce well the observed structure of the Universe, so the LSP is a good candidate to solve the Dark matter problem.

  44. Observational constraints on m and l. m~0.3 l~0.7 Astro-ph 0007333

More Related