MPI Kernphysik, Heidelberg Humboldt Univ. Berlin Ruhr-Univ. Bochum Univ. Hamburg LSW Heidelberg Univ. Tübingen Ecole Polytechnique, Palaiseau APC Paris Univ. Paris VI-VII Paris Observatory, Meudon LAPP Annecy LAOG Grenoble LPTA Montpellier CEA Saclay CESR Toulouse Durham Univ. Dublin Inst. for Adv. Studies Charles Univ., Prague Yerewan Physics Inst. North-West Univ., Potchefstroom Univ. of Namibia, Windhoek VHE Gamma Ray Astronomy with the H igh E nergy S tereoscopic S ystem: Highlights W. Hofmann MPIK Heidelberg

MPI Kernphysik, Heidelberg Humboldt Univ. Berlin Ruhr-Univ. Bochum Univ. Hamburg LSW Heidelberg Univ. Tübingen Ecole Polytechnique, Palaiseau APC Paris Univ. Paris VI-VII Paris Observatory, Meudon LAPP Annecy LAOG Grenoble LPTA Montpellier CEA Saclay CESR Toulouse Durham Univ. Dublin Inst. for Adv. Studies Charles Univ., Prague Yerewan Physics Inst. North-West Univ., Potchefstroom Univ. of Namibia, Windhoek VHE Gamma Ray Astromony with the H igh E nergy S tereoscopic S ystem: Highlights W. Hofmann MPIK Heidelberg September 28, 2004: Inauguration of the H.E.S.S. telescopes

Four telescopes, 107 m 2 mirror area each 960 PMT cameras, field of view 5 o Observation in moonless nights, ~1000 h / year Each night several objects are tracked and ~300 images recorded per second First analysis (almost) online in the same night on PC cluster in Namibia Final analysis and calibration in Europe Energy threshold: ~ 100 GeV Sensitivity: 1% Crab in 25 h

H.E.S.S. Highlights Galactic sources Galactic plane survey Supernova remnants Pulsar wind nebulae Binaries The Galactic Center Extragalactic sources Details & physics discussion in parallel sections

H.E.S.S. Highlight: Galactic Plane Survey

15 new TeV sources + 3 known Scale height: ≈ 0.3 o rms ≈ molecular gas  S. Funk, OG 23  A. Lemiere, OG 23

Ensemble characteristics Most sources are extended (size resolved if > 2…3’) Source size Photon index Spectra measured for all sources; relatively hard, = 2.3

What are they ? 5 sources could be associated with SNR, e.g. HESS J could be pulsar wind nebulae, typically displaced from the pulsar some coincide with EGRET, ASCA, … unidentified sources 3 have no counterpart known to us “beam size” (smoothed image)

HESS J : now identified Beam White et al Brogan et al cm VLA Ubertini et al., 2005 Integral HESS J (smoothed image)

HESS J , J : no counterpart (yet) (smoothed image)

H.E.S.S. Highlight: Resolved Supernova-Remnants H.E.S.S. Highlight: Resolved Supernova-Remnants SNR as cosmic particle accelerators Predicted power law spectrum dN/dE ~ E -2…2.2 Efficiency 10-50% Imaged using secondary gamma rays created in interactions with ambient medium

H.E.S.S. Highlight: Resolved Supernova-Remnants H.E.S.S. Highlight: Resolved Supernova-Remnants RX J  D. Berge, OG 22

Spectra Preliminary Index ~ 2.1 – 2.2 Little variation across SNR Cutoff or break at high energy  Acceleration of primary particles in SNR shock to well beyond 100 TeV

H.E.S.S. Gamma rays ASCA X-rays NANTEN CO at ~1 kpc

Primary population: e or p ? Electron model B ~ 10 G Need about 10 G B field to match flux ratios Simplest electronic models don’t work well

RX J “Vela Junior” Feb (3.2 h) New 04/05 data  N. Komin, OG 22 Flux ~ Crab Index 2.1 ± 0.1 ROSAT contours 3D-Analysis Preliminary

H.E.S.S. Highlight: Pulsar Wind Nebulae Pulsar wind creates void Pulsar wind termination shock Blondin et al. ApJ 563 (2001) 806 Pulsar winds have modest energetics compared to SN ejecta, but … most of the energy is in electrons radiative loss time scales for e ± are a few 1000 y, versus 10 7 y for p High ISM density Low ISM density Blondin et al. Reverse shock crushes PWN Asymmetric PWN due to collimated wind SNR reverse shock crushing into PWN

H.E.S.S. Highlight: Pulsar Wind Nebulae Vela pulsar ROSAT contours  B. Khelifi, OG 22 Preliminary Vela X hard spectrum  ≈1.9 or  ≈1.5  cutoff extends to 50 TeV no emission from vela pulsar detected

Another pulsar wind: MSH Contours: Rosat Greyscale: Radio  B. Khelifi, OG 22 Photon index 2.27 ± 0.03 ± 0.20

HESS J X-rays Gaensler et al. TeV  O. de Jager, OG 22

H.E.S.S. Highlight: Distant and Close Binaries Mar 04 Douglas Gies (CHARA, GSU) William Pounds March 04 PSR B year highly eccentric orbit around ~10 M  Be star closest approach ~10 13 cm or ~20 stellar radii Pulsar eclipsed

PSR B PSR B first variable galactic TeV source early March 04Apr./May 04Feb. 04 PSR B HESS J  S. Schlenker, OG 22

Distant and Close Binaries  M. de Naurois, OG 22 with more data …

Microquasar LS 5039 Microquasar LS 5039 first detection of TeV emission from a microquasar Paredes J. M. et al., A&A 2002 RA (mas) fueled by wind accretion(?) compact 4 (?) M  object in eccentric 4 day orbit around M  star closest approach ~10 12 cm or ~2 stellar radii

Spectral energy distribution Index 2.12 ± 0.15 Expect strong attenuation of gammas in photon field of massive star Hadronic component ? Orbital modulation ??

SNR G GC The center of our Galaxy Sgr A East SNR ? Black hole ? DM Annihilation ? PWN

Sagittarius A Colors: H.E.S.S. Contours: Radio Point-like core Extended tail Similar to NFW profile Angular distribution syst. error

Gamma ray spectrum Preliminary Power law, index 2.3 No significant variability on year scale on month scale on day scale on hour scale on minute scale (in ~40 h obs. time distributed over 2 years)  L. Rolland, OG 22 Preliminary

Dark matter annihilation ? 20 TeV Neutralino 20 TeV KK particle proposed before H.E.S.S. data proposed based on early H.E.S.S. data  J. Ripken, OG 22 Preliminary

H.E.S.S. Highlight: Galactic center region

GC molecular clouds Tsuboi et al. 1999

H.E.S.S. Highlight: Galactic center region  J. Hinton, OG 21

Diffuse emission from the GC ridge Spectral index 2.29 ± 0.07 ± 0.20 Implies harder CR spectrum than in solar neighborhood  Proximity of accelerator and target

gamma rays CS (subtracted)

Extragalactic TeV astronomy Physics of AGN jets Density of cosmological extragalactic background light (EBL) EBL x x x  VHE  EBL  e + e -

H.E.S.S. Highlight: New distant blazar sources Costamante & Ghisellini, ES z = ~12  H z = ~10   S. Pita, OG 23  M. Tluczykont, OG 23 Preliminary

Spectra & E xtragalactic B ackground L ight 1 ES 1101  = 2.9±0.2 H 2356 (x 0.1)  = 3.1±0.2 EBL Source spectrum  = 1.5 Preliminary

Spectra & E xtragalactic B ackground L ight 1 ES 1101  = 2.9±0.2 H 2356 (x 0.1)  = 3.1±0.2 too much EBL Source spectrum  Upper limit on EBL Preliminary

Spectra & E xtragalactic B ackground L ight 1 ES 1101  = 2.9±0.2 H 2356 (x 0.1)  = 3.1±0.2 too much EBL Not really a solution: add huge amount of UV photons to EBL  problems with source energetics, X-ray/gamma-ray SED ratio UV EBL Preliminary

X X X X

Spectra & E xtragalactic B ackground L ight lower limits from galaxy counts measure- ments upper limits Reference shape HESS limits X X EBL resolved Universe more transparent

Conclusion First H.E.S.S. results demonstrate that latest generation Cherenkov instruments have reached the critical sensitivity threshold Lots of interesting stuff out there – hard spectra and extended sources We’re looking forward to explore this domain further, together with CANGAROO, MAGIC, VERITAS, … MACE See talks and posters (OG 21, OG 22, OG 23, OG 27) for details on H.E.S.S. results, also M87 detection, PSK 2005, 2155 spectra, Crab, Mkn 421, … SNR, pulsar, microquasar, NGC253, … limits, …