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La nascita della astronomia dei raggi cosmici? Indicazioni dall' Osservatorio P. Auger Aurelio F. Grillo Teramo 8/05/08
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Nuclear (p, He.... Fe) component
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Knee Ankle ? Few/km sq per century
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p p? Nuclei
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for extragalactic protons On CMBR photons
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The Auger hybrid concept
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Almost completely operating, now 1 year full observatory !
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Fluorescence light Fluorescence Detector FDSurface Detector SD
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The Auger hybrid concept
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The spectrum: most statistically significant from SD calibrated in energy by “hybrid” events - energy systematic error ~22 %, mostly from systematic of the FD detector (fluorescence yield, atmospheric transparency....) Surface Detector SD Fluorescence Detector FD
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Ultra High Energy CR spectrum ICRC07
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Evidence for GZK cutoff? Likely fit
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Cosmic Ray astronomy? If UHECRs origin is astrophysical, astronomy may be possible above some x 10 19 eV if particles are protons (and IG magnetic fields small)
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If UHECRs origin is astrophysical, astronomy may be possible above some x 10 19 eV if particles are protons (and IG magnetic fields small) Around ~10 20 eV particles can only arrive from within ~ 100 Mpc (in case of GZK) Cosmic Ray astronomy?
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If UHECRs origin is astrophysical, astronomy may be possible above some x 10 19 eV if particles are protons (and IG magnetic fields small) Around ~10 20 eV particles can only arrive from within ~ 100 Mpc (in case of GZK) A statistically significant correlation with sources in the GZK spere would unambiguously prove the reality of the cutoff (and give hints on the nature of sources) Cosmic Ray astronomy?
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The “Telescope” - Angular resolution ~ 1 degree - Pointing Accuracy ~ 1 degree - Charged Messengers => deviation in mag. fields
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Exposure of the experiment in Galactic coordinates
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The (Aug. 2007) astronomy analyses ~9000 km 2 sr yr, trigger efficiency ~100%
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Search for point sources: the motivation Small magnetic deflection Only nearby sources if GZK feature ok Nearby Universe anisotropic Regular Gal. B field
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Search for point sources: the motivation Small magnetic deflection Only nearby sources if GZK feature ok Nearby Universe anisotropic Indication of GZK from spectrum Bounds on photons/neutrinos Acceleration favoured vs. top-down Regular Gal. B field
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Search for point sources: the method Need to search correlations of a selected sample of events with astrophysical objects.... how and where? Large parameter space: -- events -> Energy, angular aperture Sources -> what sources: type, distance (z)........
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Search for point sources: the method Need to search correlations of a selected sample of events with astrophysical objects.... how and where? Large parameter space: -- events -> Energy, angular aperture Sources -> what sources: type, distance (z)........ Method: perform a scan in the parameters space, after having chosen sources of a given type from a catalogue Chosen Veron-Cetty, Veron Catalogue of AGNs
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Search for point sources: the method Some definitions: p -- exposure-weighted fraction of the sky accessible to observation, covered by windows of radius ψ centred on the selected sources. P -- probability that k or more out of a total of N events from isotropic flux are correlated by chance with the selected objects at the chosen angular scale this probability needs 'penalization' i.e. P fin = P/N t (from MC) z<0.018
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Search for point sources: the strategy Performed an exploratory scan. E th > 4 10 19 eV z < 0.024 Of 15 events with E th > 5.7 10 19 eV, 12 correlated within with AGNs with z<0.019, while 3.2 expected with these parameters
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Search for point sources: the strategy Performed an exploratory scan. E th > 4 10 19 eV z < 0.024 Of 15 events with E th > 5.7 10 19 eV, 12 correlated within with AGNs with z<0.018, while 3.2 expected with these parameters Further search performed with these a priori fixed parameters, ending when the probability to incorrectly reject hisotropy hypotesis < 1% Search started May 2006, ended May 2007 when 6/8 events found correlating. In sample May 2006 – Aug 2007 8/13 correlating P= 1.7 10 -3
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Search for point sources: the strategy Rescan whole dataset with improved reconstr. algorithm to fix parameters. 20 out of 27 events correlated (a posteriori) P fin (iso)~10 -5
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Search for point sources: the PAO Sky Map Equatorial coordinates South pole SuperGalactic plane Galactic plane
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Search for point sources: the PAO Sky Map PAO events
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Search for point sources: the PAO Sky Map AGNs from VC-V catalogue (z<0.018) PAO events
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Search for point sources: the PAO Sky Map CenA Virgo AGNs from VC-V catalogue PAO events
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Search for point sources: the PAO Sky Map CenA Virgo AGNs from VC-V catalogue PAO events
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Search for point sources: the PAO Sky Map CenA Virgo AGNs from VC-V catalogue If region of Galactic plane excluded, 19 out of 21 events do correlate PAO events
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Search for point sources: the PAO Sky Map CenA Virgo AGNs from VC-V catalogue Leiden – Argentine – Bonn Hydrogen Survey PAO events
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Search for point sources: the PAO Sky Map
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Both for real events and simulated sets of same size, either isotropic or source
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CenA Search for point sources: the PAO Sky Map
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AGNs: sources or tracers??
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Search for point sources: the PAO Sky Map AGNs: sources or tracers??
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Search for point sources: the PAO Sky Map AGNs: sources or tracers?? No significant correlation (yet) with Abell,REFLEX, NORAS catalogues of clusters of galaxies, nor starburst radio galaxies
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Search for point sources: the PAO Sky Map AGNs: sources or tracers?? No significant correlation (yet) with Abell,REFLEX, NORAS catalogues of clusters of galaxies, nor starburst radio galaxies
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Search for point sources: the PAO Sky Map AGNs: sources or tracers?? No significant correlation (yet) with Abell,REFLEX, NORAS catalogues of clusters of galaxies, nor starburst radio galaxies
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Search for point sources: the PAO Sky Map CenA
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Search for point sources: the PAO Sky Map The GZK “horizon”
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Search for point sources: the PAO Sky Map The GZK “horizon” Indication of the need of energy shift? Too early, exclude other selection effects (foreground, bias of method..)
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Search for point sources: the PAO Sky Map Magnetic fields Extragalactic (irregular)
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Search for point sources: the PAO Sky Map Magnetic fields Extragalactic (irregular)
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Possibly Some open issues: -- Statistic: 27 events E> 5.7 10 19 eV. One more year of data will double N. Birth of (nuclear) Cosmic Ray Astronomy?
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Possibly Some open issues: -- Statistic: 27 events E> 5.7 10 19 eV. One more year of data will double N. -- Energy: at 5.7 10 19 eV GZK Horizon ~ 200 Mp > 75 upward shift of energy calibration consistent with sistematic error can reconcile Birth of (nuclear) Cosmic Ray Astronomy?
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Possibly Some open issues: -- Statistic: 27 events E> 5.7 10 19 eV. One more year of data will double N. -- Energy: at 5.7 10 19 eV GZK Horizon ~ 200 Mp > 75 but... upward shift of energy calibration consistent with sistematic error can reconcile -- Type of particles: some hint of heavy nuclei, larger deviation in GMF Birth of (nuclear) Cosmic Ray Astronomy?
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HiRes does not confirm
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We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected Conclusions?
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We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected Conclusions?
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We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected Conclusions?
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We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected A very interesting future is approaching!! Conclusions?
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Search for point sources: the PAO Sky Map Magnetic fields Difficult – impossible if nuclei
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Search for point sources: the PAO Sky Map Magnetic fields
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Search for point sources: the PAO Sky Map Magnetic fields
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Search for point sources: the PAO Sky Map Magnetic fields
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Search for point sources: the PAO Sky Map Magnetic fields Problem not serious (yet!) also: non correlating events chance correlating events Preliminary!!
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HiRes HiRes energy x 0.83
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CenA Search for point sources: the PAO Sky Map Preliminary!! No distinctive feature of correlated AGNs identified. AGNs: sources or tracers?
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