Very High Energy Gamma Ray Astronomy- A new window to the Universe

Christian StegmannUniversity of Erlangen-NurembergHumboldt University Berlin

XXV Physics in Collisions, Prague 2005

The sky at energies of 1 eV

Strkste Quelle 1 photon km-2s-1The sky at energies of 1 TeVStatus PIC 2004Surprises and progress in 2004/2005

Pulsars, unknown sources, scans

Terra Incognita

The main players

Imaging Atmospheric Cherenkov Telescopes

Detection of gamma-rays via the Cherenkov light from air showersIntensity shower energyImage orientation shower directionImage shape primary particle

Stereoscopic Observation TechniqueSource position

VeritasH.E.S.S. CANGAROO IIIMAGIC artist viewCherenkov Telescopes Worldwide

Cherenkov Telescopes Worldwide

Status# TelMirror(m2)F.o.V(o)Energy threshold (GeV)MAGICData taking08/200412393.530-50H.E.S.S.Data taking12/200341085100CANGAROO IIIData taking03/20044 574~250VeritasStart10/2006Prototyp running41004.5~100

My personal highlights in 2004

My personal highlights in 2004First ever astronomical gamma-ray imageNature 432, 75 (2004)The supernova remnant RX J1713.7-3946H.E.S.S.

H.E.S.S.: First sensitive scan of the inner GalaxyMy personal highlights in 2004

8 new sources!Science 307, 1938 (2005) My personal highlights in 2004

Galactic Sources

Crab NebulaVLT, optical Supernova from 1054 A.D. 6500 Ly distance 33 ms pulsar Plerion relativistic electron plasma heated by the central pulsar

The standard candle of gamma-ray astronomy

Seen by all instruments

Krebs NebelCrab Nebula

Krebs NebelH.E.S.S.preliminaryCrab Nebula

Shell type supernova remnantsCas A, Chandra, Rntgen

Cosmic Ray Accelerators?Why supernova remnants?large energy release(dE/dt)SN = 10.(dE/dt)CRacceleration in shock waves element composition of Cosmic RaysWhy gamma-rays?Electrons: -radiation via IC Hadrons: 0pointingSearch strategiesnon-thermal X-raysscansCas A, Chandra, X-rays

The supernova remnant RX J1713.7-3946ROSAT(keV)Age ~1500 years

H.E.S.S. 200433 h with 4 Telescopes210 GeV threshold

Energy spectrumOne-zone model

Power law dN/dE = K E-

Spectral index: = 2.2preliminary

ImplicationsUnambiguous proof thatsupernova shock waves are cosmic accelerators;they accelerate particles to O(100 TeV)But are they the sources of (nucleonic) cosmic rays ?Is the kinetic energy released in the explosion converted to cosmic-ray energy with O(10%) efficiency ?

E2 dN/dEln(E)radio infrared visible light X-rays VHE -rays Electron or hadron accelerator?

Electron acceleratorF.A. Aharonianradio X-rays VHE -rays E2 dN/dE (erg cm-2 s-1)log(E/eV)

Electron acceleratorradio X-rays VHE -rays log(E/eV)E2 dN/dE (erg cm-2 s-1)

Spatially resolved spectraTeV photon indexH.E.S.S.preliminary

Proton acceleratorContinuous proton injection over 1000 yearsInjection spectrum: power law, index ~2Different cutoff shapes

F.A. Aharonian

H.E.S.S. 2004~3 hVela JuniorH.E.S.S. 2005 preliminary~10 h(see also CANGAROOApJ, 619, L163-L165 (2005) )

HESS J1834-087HESS J1804-216HESS J1640-465Beam widthMore possible SNR associations Separation of electron and hardon component Multi-wavelength observations Correlation with molecular clouds

The binary systemPSR B1259-63/SS 2883

The first variable galactic TeV-source

The binary system PSR B1259-63 / SS 2883Discovery (March 2004):48 ms Pulsar3.4 y periodBe Star10 MPeriastron 7. March 2004Complex interaction between pulsar and star during periastron

The PSR B1259-63 field of viewMarch 04Apr./May 04Feb. 04H.E.S.S.

The PSR B1259-63 field of viewHESS J1303-631Mrz 04Apr./Mai 04Feb. 04What are these dark accelerators?

The Galactic Centre

The Galactic CentreSeen byCANGAROOWhipple/VeritasH.E.S.S.

Das Galaktische ZentrumH.E.S.S. 200450 h with 4 telescopespreliminary

Sagittarius AH.E.S.S. 2004 preliminary

Sagittarius APoint-like coreExtended tailDistance to Sgr A*1430 galactic longitude1230 galactic latitude

Sgr A East not excluded

H.E.S.S. 2004 preliminary

Gamma ray spectrumPower law, index 2.3No significant variabilityPreliminary

HESS J1745-290Either Sgr A* ...

Supermassive (M 3.106 M) rotating black hole in a magnetic field huge electromotive force (e.m.f.) able to accelerate protons up to 1018 eV (0) or electrons (-rays via IC)... or Sgr A East

10000 years old supernova covers Sgr A* Fermi-acceleration of Cosmic Rays in expanding shock wave

or

Dark matter annihilation ?For pure DM originrather large masslarge x-section or densityunusual spectrum or superposition of spectraPreliminary20 TeV Neutralino20 TeV Kaluza Klein particleH.E.S.S. 2004

Extragalactic Sources

Active Galactic Nuclei

Active Galactic NucleiActive Galactic Nuclei Supermassive black holes, M 109 M Accretion disc with relativistic jet

Blazar-Typ: Jet towards Earth Doppler-boost of emission spectra TeV -radiation

Active Galactic Nuclei

Study of the infrared background light CosmologyPhysics of compact objectsand relativistic jets and Absorption in extragalacticbackground light (Infrared)(TeV) + (IR) e+e-

-ray horizonH.E.S.S., CANGAROO, VeritasMAGICDifferent models for the extragalactic background light (EBL)simulated MeasurementsBlanch & Martinez 2004

AGN Physics e.g. Mkn 421 (z=0.031)Emission spectraSynchrotron-Self-ComptonFlaresIntrinsic Cut-offsKonopelko et al.ApJ 597 (2003) 851Mkn 421 flares 2004Mkn 421 Cut-offsMJDFlux [10-11cm-2 s-1]Mkn 421 multi-wavelength spectra [Hz]F [erg cm-2 s-1]Ecut [TeV]

Many sources at large zMany sources at the same z

H.E.S.S. 2004H.E.S.S.2004Flux(E>2TeV) [cm-2 s-1]

Simultaneous ObservationsMAGICH.E.S.S.e.g. MAGIC & H.E.S.S.

Simultaneous observation of a large energy range

e.g. Mkn 421 flare in 2003/2004

-ray horizonMrk421(H.E.S.S.,MAGIC)Mrk5011ES 1959+650(MAGIC)PKS 2155-304(H.E.S.S.)H1426+428

AGN limits19 BL Lacs and other AGNs z between 0.002 and 0.31-5 h obs. timelimits 1-3% of Crab flux

SignificanceMkn501H.E.S.S.Significance

Upgrades

UpgradeH.E.S.S. II Improved sensitvity Reduced threshold O(20 GeV) Ready 2007-2008

MAGIC II 2nd telescope same as Magic I (stereoscopy) Photosensors with high QE Ready in 2006

Highlights 2004/2005H.E.S.S. scan 2004: 8 new sourcesH.E.S.S. First image of a TeV sourceThe largest TeV sourceH.E.S.S. First variable galactic sourceAn unknown sourceThe last year:Big successes and discoveriesCrab-spectrumabove 100 GeVVeritasThe Crab seen by

This is an excess mapState how amazingly good the agreement with X-rays isFirst time ever two sources of TeV gamma-rays in one field of view (proves the advantage of a large fov)First time ever two sources of TeV gamma-rays in one field of view (proves the advantage of a large fov)Stress improvement in angular resolution