Particle AstrophysicsCosmic raysGamma-ray astronomyNeutrino astronomy

Multi-messenger astronomyProtons, g-rays, n, [gravitational waves] as probes of the high-energy universeProtons: directions scrambled by magnetic fields Photons: straight-line propagation but reprocessed in the sourcesextragalactic backgrounds absorb Eg > TeVNeutrinos: straight-line propagation, unabsorbed, but difficult to detect

Energetics of cosmic raysEnergy density: rE~ 10-12 erg/cm3 ~ B2 / 8pPower needed: rE / tesc galactic tesc ~ 3 x 106 yrsPower ~ 10-26 erg/cm3s Supernova power:1051 erg per SN~3 SN per century in disk~ 10-25 erg/cm3sSN model of galactic CRPower spectrum from shock acceleration, propagation

Problems of simplest SNR shock modelExpected shape of spectrum:Differential index a ~ 2.1 for diffusive shock acceleration aobserved ~ 2.7; asource ~2.1; Da ~ 0.6 tesc(E) ~ E-0.6 c tesc Tdisk ~100 TeV Isotropy problem Emax ~ bshock Ze x B x Rshock Emax ~ Z x 100 TeV with exponential cutoff of each componentBut spectrum continues to higher energy: Emax problem

Expect p + gas g (TeV) for certain SNRNeed nearby target as shown in picture from Nature (April 02)Interpretation uncertain; seeEnomoto et al., Aharonian (Nature); Reimer et al., astro-ph/0205256 Problem of elusive p0 g-rays

Spectrum normalizes atmospheric nGeV to TeV important for atmospheric n Good agreement < 100 GeVAMS, BESSLack of TeV data; new expts:Magnetic spectrometers:PAMELA (2003)AMS on Space Station (2005)Meanwhile, new m-flux measurements Em > 100 GeV Timmermans talk on L3+CSomewhat below previous measurements

Knee of spectrumDifferential spectral index changes at ~ 3 x 1015eV a = 2.7 a = 3.0Continues to 3 x 1018 eVExpect exp{-E / Z Emax} cutoff for each ZFine-tuning problem: to match smoothly a new source with a steeper spectrum (Axford)How serious is this?

Speculation on the knee

Transition to extragalactic origin?Ankle new population of particles?Suggestive evidence: hardening of spectrum change of compositionMeasurements:EnergyDepth of maximum (Xmax)Nm / Ne

Air shower detectors

Measuring the energy of UHECRGround array samples shower frontWell-defined acceptanceSimulation relates observed ground parameter to energyFluorescence technique tracks shower profileTrack-length integral gives calorimetric measure of energyXmax sensitive to primary mass: Xmax ~ L ln(E0/A)

Xmax vs EnergyProtons penetrate deeper into atmosphereHeavy nuclei develop higher upPlot shows a summary of data over 5 decadesSeveral techniquesSome dependence on models of hadronic interactions (R. Engels talk)

Xmax vs EnergyLines indicate trend of data:Light to heavy above the knee (~1016 1017 eV)Heavy to light at the ankle (~1018 1019 eV) AGASA looks at m/e ratio in shower front and sees no evidence for change of composition at the ankle

Energy of extragalactic componentEnergy density:CR > ~ 2 x 10-19 erg/cm3Estimate requires extrapolation of UHECR to low energyPower required >CR/1010 yr ~ 1.3 x 1037 erg/Mpc3/s10-7 AGN/Mpc3Need >1044 erg/s/AGN1000 GRB/yr Need >3 x 1052 erg/GRB

Highest energy cosmic raysGZK cutoff?Expected from energy loss in 2.7o background for cosmological sourcesAttenuation length in microwave background

Compare AGASA & HiResExposure (103 km2 yr sr):AGASA: 1.3HiRes (mono): 2.2Number events >1020AGASA: 10 (+2?)HiRes (mono): 2?Both detectors have energy-dependent acceptance (different)Need more statistics and stereo results

Ground arrayFluorescence detector

Models of UHECRBottom up (acceleration)Jets of AGNExternal Internal (PIC models)GRB fireballsAccretion shocks in galaxy clusters Galaxy mergersYoung SNRMagnetarsObserved showers either protons (or nuclei)Top-down (exotic)Radiation from topological defects*Decays of massive relic particles in Galactic haloResonant neutrino interactions on relic ns (Z-burst)Large fraction of g-showers (especially if local* origin)

( Incomplete list--Refs. in written version ) If no cutoff, require a significant contributionfrom nearby sources. Local overdensity ofgalaxies is insufficient if UHECR sourcedistribution follows distribution of galaxies.

Biggest eventComparison to Proton showersIron showers g showers

Flys Eye, Ap. J. 441 (1995) 295

Most of shower absorbed, mostly muons survive to the ground Heavy primaries produce more m Incident photons produce few m Analysis of vintage (aged ~25 yrs) data from Haverah Park array possible with modern simulation tools Results place interesting limits limits on Top-Down models: UHE events from decaying, massive relics accumulated in the Galactic halo would be mostly photon-induced showers. Such models are therefore disfavoredSimilar limit on g/p from AGASA

Auger hybrid eventFluorescence detector viewSurface detector viewEngineering Array: SD with 40 modules ~ 100 km2 viewed by fluorescence detector. Now operating in Argentina. 100 more tanks running in 2003.

Active Galaxies: JetsVLA image of Cygnus ARadio Galaxy 3C296 (AUI, NRAO). --Jets extend beyond host galaxy. Drawing of AGN core

Egret blazarsBlazars are AGN with jet illuminating observer.

Two-component spectra interpreted as synchrotron radiation (low energy) plus inverse Compton generated by high-energy electrons accelerated to high energy in relativistic jets (G ~ 10).

A few nearby blazars have spectra extending to > TeV observed by ground-based Imaging Atmospheric Cherenkov Telescopes (IACT).

AGN Mulitwavelength observationsSSC, EC, PIC models1st peak from electron synchrotron radiation2nd peak model-dependent; predict n flux if PICInterpretation complex:Sources variableLocations of peaks depend on source-- factor of >100 range of peak energyNew detectors (GLAST, HESS, MAGIC, VERITAS) will greatly expand number, variety of sources

Solar arrays for g-ray astronomy explore down to ~100 GeV:CelesteSTACEECELESTE, STACEE in operation

TeV g BlazarsFive detectedMrk 421 (Z = 0.031)Mrk 501 (Z = 0.034)1ES2344+514 (Z = 0.044)1H1426+428 (Z = 0.129)1ES1959+650 (Z = 0.048)* * Whipple, IAU Circular 17 May 2002Emax vs Z probes era of galaxy-formation through IR background

Blazar spectra at high energyMrk 421 & Mrk 501, CutoffsIntrinsic?Effect of propagation?Variable sourcesLow intensity softer spectrumInterpretation under debateNeed more observations of more sources at various redshifts

HEGRA plots from Aharonian et al. astro-ph/0205499. DifferentEcut of 421 and 501 suggest cutoffs are intrinsic.

Comparable analysis of Whipple extends to lower energy. Seeing comparable cutoffs, they suggest effect is due to propagation. Krennrich et al., Ap.J. 560 (2002) L45 both at z ~ .03

Sky map from the Milagro detectorMilagro is a compact air shower detector that uses a 60 x 80 m water Cherenkov pool covered and surrounded by air shower detectors.

Detectors for gamma-ray astronomyEgret 1991-2000Presently runningFutureAMS**Secondary Mode of operation*Multiple telescope arrays for stereo operation

Gamma-ray astronomypresent and futureA. Morselli, S. Ritz

H.E.S.S. First eventsJune, 2002

Gamma-ray burstsCosmological burstsStudies of afterglows (ROTSE, Beppo-Sax ID) determine Z ~ 1Hypernova or coalescing compact objectsRelativistic jets (G ~ 100)Acceleration at internal shocksPossible acceleration when jets interact with environmentAre GRBs sufficiently powerful and numerous to supply the UHECRs? This question currently under debateSoft Gamma RepeatersGalactic magnetars, B ~ 1015 GSatisfy ebcBR > 1020 eVSWIFT to be launched in 2003

Neutrino AstronomySN1987A, Solar nHigh-energy n astronomy[DUMAND]Baikal, AMANDACurrently runningAtmospheric ns detectedLimits on point sources, diffuse high-energy ns, WIMPs, monopolesKm3-scale projects getting underwayAMANDA: astro-ph/0205019Skymap of upward events

South PoleDark sectorAMANDAIceCubeDomeSkiway

Expected sensitivity AMANDA 97-02 data4 years Super-Kamiokande 8 years MACRO 170 days AMANDA-B1010-1510-14m cm-2 s-1declination (degrees) southern sky northern sky

Development of kilometer-scalen telescopes ... complementary sky-views and techniques IceCube in Antarctic iceAntares + Nemo, NestorKm3 in theMediterranean Sea

Skymaps and exposure to gamma-ray burstersBATSE 2706 GRBs Beppo-SAX 126 GRBsPlot by Teresa Montaruli is grey-scale image of sky coverage for upward events (black = no coverage, white = full coverage). Applies to En< PeV when Earth needed to shield against downward events.

Neutrino flavor IDP p nm + m e + ne + nm nm : ne : nt ~ 2 : 1 : 0 at productionoscillations give 1 : 1 : 1 at EarthEn < PeV nm: upward m track ne, nt: cascadesEn > PeVRt ~ 50 m / Et (PeV) nt gives double bang or lollipop signature (large cascade preceded or followed by a long, cool track)

n Propagation in the EarthLower hemisphere 50% opaque for En ~ PeVRegeneration of nt nt t n cascade:Look for excess of upward cascades between 0.1 and 10 PeVFor En > PeV can use downward neutrinos as well as upward

Expected signals in km3Possible point sources:GalacticSNR 0 - 10 events / yr m-quasars 0.1 - 5 / burst ~ 100 / yr, steady sourceExtra-galacticAGN jets 0-100 / yrGRB precursor (~100 s)~ 1000 bursts / yr ~ 0.2 events / burstGRB jet after breakoutsmaller mean signal / burstNearby bursts give larger signal in both cases

Proposed detectors for En ~ EeVAir shower arraysSignature: Horizontal EASVeff ~ 10 m.w.e. x areae.g. 30 Gt for Auger(Acceptance ~30 x larger for nt in Auger)>1000 Gt for EUSO, OWLRadio detectorsRICE (antennas in S.P. ice)ANITA (antennas on long-duration Antarctic balloon)SALSA (in salt domes)GLUE (Goldstone antenna search for n interact in moon)

Note: despite larger Veff , rates may be comparable or smaller than in Km3 detectors with lower Ethreshold by an amount depending on source spectrum

SummaryNeed more statistics and cross-calibration for ultra-high energy cosmic raysExpect another leap in g-astronomy with GLAST and new ground telescope arrays Kilometer-scale neutrino telescopes to open new window on energetic UniverseMany active and new experiments in this rapidly developing field -- stay tuned!

Diffuse galactic secondaries p + gas p0, p+/-, antiprotons p0 g g [p+/- n]Hard g-spectrum suggests some contribution from collisions at sourcesPhys.Rev.Lett. 88 (2002) 051101

Lessons from the heliosphereACE energetic particle fluences:Smooth spectrum composed of several distinct components:Most shock acceleratedMany events with different shapes contribute at low energy (< 1 MeV)Few events produce ~10 MeVKnee ~ Emax of a few eventsAnkle at transition from heliospheric to galactic cosmic rays

R.A. Mewaldt et al., A.I.P. Conf. Proc. 598 (2001) 165

Heliospheric cosmic raysACE--Integrated fluences:Many events contribute to low-energy heliospheric cosmic rays;fewer as energy increases.Highest energy (75 MeV/nuc) is dominated by low-energy galactic cosmic rays, and this component is again smoothBeginning of a pattern?

R.A. Mewaldt et al., A.I.P. Conf. Proc. 598 (2001) 165

Reconstruction Handles for neutrino astronomy

Energy resolutionSystematics DE / E ~20% for ~1018 eV By cross-calibrating different detectorsBy using different modelsBy comparing spectra of different experiments and techniquesFluctuations in Smax underestimate E if measured at max, overestimate if past max

GRB modelAssumes E-2 spectrum at source2.5 x 1053 erg/GRB0.4 x 1037 erg/Mpc3/sEvolution like star-formation rateGZK losses includedGalactic extragalactic transition ~ 1019 eVBahcall & Waxman, hep-ph/0206217

AGN modelAssumes two-component spectra steep at high energy1039 erg/Mpc3/s note high valueEvolution, GZK lossesCompares to AGASA data, cannot explain ~5 eventsTransition to extragalactic at low energy

Berezinsky et al., hep-ph/0204357Curves 2,3,4 with local overdensity of sources. 2 is observed overdensity.

Comparison of Haverah Park photon limit with theory