Navarro, J. L.

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Astronomy of ultra-high energy neutral particles with the Pierre Auger Observatory

Repositorio Institucional Universidad de Granada

Astronomy of ultra-high energy neutral particles with thePierre Auger Observatory23rd European Cosmic Ray Symposium“Lomonosov University”, Moscow.July 3-7  2012J.L. Navarro1 for the Pierre Auger Collaboration21 Dpto. Física Teórica y del Cosmos & CAFPE, University of Granada, Spain2 Avd. San Martin Norte S/N, Malargüe, ArgentinaUniversidad de GranadaShort review of the Pierre Auger ObservatoryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationHybrid detector of Cosmic Rays. Objectives:Energy Cutoff at the highest energies? Ankle?Direction Is the UHECR flux isotropic ? Which are the UHECRs sources?Mass composition Is the UHECR flux dominated by light/heavy ions?Pierre Auger ObservatoryShort review of the Pierre Auger ObservatoryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationHybrid detector of Cosmic Rays. Objectives:Energy Cutoff at the highest energies? Ankle?Direction Is the UHECR flux isotropic ? Which are the UHECRs sources?Mass composition Is the UHECR flux dominated by light/heavy ions?Pierre Auger ObservatoryIt has the capability of detecting neutral particles!Astronomy with neutral particles in the Pierre Auger ObservatoryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationThree neutral particles:Photons:Electromagnetic interaction-Deep interaction in the atmosphere- Electromagnetic shower(high e-m content, absence of muons)Neutrinos:Weak interaction- Interact at any point of atmosphere- Hadronic + electromagneticextensive air showerNeutrons:Strong interaction- Interaction at top of atmosphere- Hadronic extensive air showerDistinguishable from “charged” cosmic rays in an event by event basis study.Distinguishable from “charged” cosmic rays only in a statistical basis study.ν search75 - 95γ , n search0 - 60Neutrino detection requires large amount of atmospherePhoton analysis at the Pierre Auger ObservatoryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationPhoton signature: Big value of XMax from fluorescence detector Smaller signal in surface detectors (Sb)  and less stations triggered.Event Selection: XMax fully contained in field of view Zenith angle < 60o At least 4 active stations within 2 km of axis4Log10(S4)X0Photon analysis at the Pierre Auger ObservatoryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationPhoton Selection: Fisher Discriminant in 3 energy bins1 – 3 EeV, 3 – 10 EeV and E>10 EeV Energy resolution  Photon selection efficiency 50 % Proton Background < 1 %Search Period: Jan 2005 to Sep 20106, 0, 0, 0, 0 candidates above 1, 2, 3, 5, 10 EeVCompatible with expected backgroundDedicated simulation for candidates study.~2% selectedPhoton analysis at the Pierre Auger ObservatoryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationICRC 2011)E [EeV] Nγ φγ95CL Eγ>E0[km-2 sr-1 yr-1]1 6 8.2 x 10-22 0 2.0 x 10-23 0 2.0 x 10-25 0 2.0 x 10-210 0 2.0 x 10-2Systematic uncertainties:is the exposure for the search period is the number of observed candidates with energy Eγ above E0 (Poisson 95%)AgasaSensitivity to ALL flavoursSensitive to ALL interaction channels (CC & NC)Large solid angle (75o 90o)Dilute mass target (air) “down going” neutrinostravels long distances in the Earthwithout losing too much E before decayingSensitivity to CC channelSmall solid angle (90º – 95º)Dense mass target (Earth crust) “Earth skimming” tau neutrinos“down-going” : “young”e.m. component at groundh35 atmHadronic showers: “old” muons dominate at groundNeutrinos at the Pierre Auger:Two analyses,“down going” and “Earth-skimming”Neutrino analysis at the Pierre Auger ObservatoryECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationOnly observables of the surface detector are usedijijijΔtdv Down-going ( > 75o) At least 4 triggered stations<signal speed>  < 0.31 m ns-1 L/W > 3 Earth-skimming (90 < < 95o) At least 3 triggered stations 0.29 m ns-1 < <signal speed>  < 0.31 m ns-1 L/W > 5SIGNATUREinclined shower with significant electromagnetic content, mainly in the “early” stationsSide View of SDTop View of SDNeutrino analysis at the Pierre Auger ObservatoryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationNeutrino Selection based on a Fisher discriminant.Search Period:Down-going: Nov 2007 – May 2010Earth-Skimming: Jan 2004 – May 20100 CANDIDATES FOUNDhadron “old shower”neutrino “young shower”early   stationslate   stationsLarger grammage of atmosphereBroader signals in few first triggered tanksShower front narrower in timeShower front extended in timeAoP 1Hadron signal (VEM)time (ns)AoP >> 1time (ns)Neutrino signal (VEM)150 nssPeakAreaNeutrino analysis at the Pierre Auger ObservatoryECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationIntegrated Neutrino Limits:Down-going: 1.7 x 10-7 GeV cm-2 s-1 sr-1Earth-skim.: 2.8 x 10-8 GeV cm-2 s-1 sr-1Limit to Cen A flux:Down-going: 1.75 x 10-6 GeV cm-2 s-1Earth-skim.:  3.17 x 10-7 GeV cm-2 s-1NeutronsCosmic RaysNeutron analysis at the Pierre Auger ObservatoryECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationNeutrons• Unstable: Only galactic neutrons detectable• Neutral: Travel in straight linesTwo approaches:Blind Search of over-densitiesAngular resolution :- 1.8o if E>1EeV- 1.5o if E>2EeVLi-Ma significance studyTargeted SearchSearch excess in gamma-ray sourcesTwo set of sources from:- Fermi Lat point source catalog- H.E.S.S. source catalog1 EeV2 EeVNeutron analysis at the Pierre Auger ObservatoryECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationNo significant excess found.Upper Limits: [km-2 yr-1]- 0.024 for E Є [1,2] EeV- 0.014 for E Є [2,3] EeV- 0.026 for E ≥ 1 EeVE > 1 EeVE > 1 EeVSet of Sources Energy Bin [EeV] SstakedFermi LAT PointSource Catalog1 – 2 2.072 – 3 0.51≥ 1 2.35H.E.S.S. Source Catalog1 – 2 -0.752 – 3 -0.40≥ 1 -0.89No significant excess found in any analysis.Data scanned fromJan 2004 to Oct 2010SummaryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger Collaboration•The Pierre Auger Observatory is a hybrid detector of Cosmic Rays that has the capability of detecting neutral primaries.•We have placed stringent limits to the flux of incoming photons,  neutrinos and neutrons.For detailed information on photon and neutron analysis refer to:The Pierre Auger Collaboration, “The Pierre Auger Observatory III: Other Astrophysical Observations”, Contributions to the 32nd International Cosmic Ray Conference, 2011arXiv:1107.4805v1For detailed information on neutrino analysis refer to:The Pierre Auger Collaboration, “Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory”, Physical Review D 84, 122005 (2011) arXiv:1202.1493More results in:www.auger.orgBackupPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationBackupBackup – Photons - SummaryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger Collaboration- Fit Gaisser Hillas χ2 < 2.5- Xmax in the field of view- Energy uncertainty < 20%- Cherenkov light contamination < 50%- Only periods with good measurement of aerosols and no clouds.- At least 4 SD active within 2 km from the axis.- QGSJETII and FLUKA hadronic models used.- Fisher Trained with 30000 proton and photon CORSIKA showers.- Hadronic background checked with 1000 simulationsUncertainties:- ∆Xmax = 13 g cm-2 , +1 (-2) candidates above 1 EeV, 0 in other energies. +10%, -25% lim.- ∆Sb = 5%- Exposure 5%- Energy scale 22%, +1 (-4) cand. above 1 EeV, 0 in other en.-->  +14%, -54% above 1EeV, +6%,-7% other en.Backup - PhotonsPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationBackup – Neutrino ResultECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationAstrophysical modelsWB. BoundNeutronsCosmic RaysNeutron analysis at the Pierre Auger ObservatoryECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationNeutrons• Unstable: Only galactic neutrons detectable• Neutral: Travel in straight linesTwo approaches:Blind Search of over-densitiesAngular resolution :- 1.8o if E>1EeV- 1.5o if E>2EeVLi-Ma significance studyTargeted SearchSearch excess in gamma-ray sourcesTwo set of sources from:- Fermi Lat point source catalog- H.E.S.S. source catalog1 EeV2 EeVBackup – Neutron summaryPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger Collaboration- Mean free path before decay: 9.2 E /EeV kpc- Distance to galactic center: 8.3 kpc- Galactic radius: 15 kpc- Only SD events with θ < 60o- Systematic uncertainty in energy determination: 22 %- Angular resolution (68% containment radius)- 1.8 above 1 EeV- 1.5 above 2 EeV- ~10% influence in total systematic- HEALPIX with resolution Nside = 128- Limit computed at 95% cl with Zech (1989) approach.Backup – Neutron Targeted SearchPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger CollaborationName 1FGL L [deg] B [deg] Distance[kpc]Name HESS L [deg] B [deg] Distance[kpc]J0835.3-4510 263.55 -2.79 0.29 ± 0.02 J0852-463 266.28 -1.24 0.2J1709.7-4429 343.10 -2.69 1.4 – 3.6 J0835-455 263.85 -3.09 0.29J1856.1+0122 34.70 -0.42 2.8 J1713-397 347.28 -0.38 1J1809.8-2332 7.39 -1.99 1.7 ± 1.0 J1616-508 332.39 -0.14 6.5J1801.3-2322c 6.57 -0.21 1.9 J1825-137 17.82 -0.74 3.9J1420.1-6048 313.54 0.23 5.6 ± 1.7 J1708-443 343.04 -2.38 2.3J1018.6-5856 248.32 -1.70 2.2 J1514-591 320.33 -1.19 5.2J1028.4-5819 285.06 -0.49 2.3 ± 0.7 J1809-193 10.92 0.08 3.7J1057.9-5226 285.98 6.65 0.7 ± 0.2 J1442-624 315.41 -2.30 2.5J1418.7-6057 313.33 0.14 2 - 5 J1640-465 338.32 -0.02 8.6Fermi LAT Point Source Catalog H.E.S.S. Source CatalogBackupPower law ~ E-2.75ECRS 2012 - J.L. Navarro for The Pierre Auger Collaboration

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Astronomy of ultra-high energy neutral particles with the Pierre Auger Observatory

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