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

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igh

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nergy W. Hofmann MPIK Heidelberg

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tereoscopic

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ystem:

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

H

September 28, 2004: VHE Gamma Ray Astromony with the igh

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nergy W. Hofmann MPIK Heidelberg

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tereoscopic

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ystem:

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

H.E.S.S. Highlight: Galactic Plane Survey   S. Funk, OG 23 A. Lemiere, OG 23 15 new TeV sources + 3 known Scale height: ≈ 0.3

o rms ≈ molecular gas

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

Photon index

What are they ?

5 sources could be associated with SNR, e.g. HESS J1834-087 3 could be pulsar wind nebulae, typically displaced from the pulsar some coincide with EGRET, ASCA, … unidentified sources 3 have no counterpart known to us

(smoothed image)

“beam size”

HESS J1813-178: now identified

(smoothed image)

HESS J1813-178 White et al. 2005 Brogan et al. 2005 20 cm VLA Ubertini et al., 2005 Integral Beam

HESS J1614-518, J1708-410: no counterpart (yet)

(smoothed image) (smoothed image)

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:  D. Berge, OG 22 Resolved Supernova-Remnants RX J1713-3946

Spectra  Acceleration of primary particles in SNR shock to well beyond 100 TeV

Preliminary

Index ~ 2.1 – 2.2

Little variation across SNR Cutoff or break at high energy

H.E.S.S.

Gamma rays ASCA X-rays NANTEN CO at ~1 kpc

Primary population: e or p ?

Electron model B ~ 10 m G •Need about 10 m G B field to match flux ratios •Simplest electronic models don’t work well

RX J0852.0-4622 “Vela Junior” Flux ~ Crab Index 2.1 ± 0.1

 N. Komin, OG 22 Feb. 2004 (3.2 h) New 04/05 data ROSAT contours

3D-Analysis Preliminary

H.E.S.S. Highlight: Pulsar Wind Nebulae Blondin et al. ApJ 563 (2001) 806 Pulsar wind termination shock High ISM density Reverse shock crushes PWN Low ISM density Blondin et al.

Pulsar wind creates void 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 Asymmetric PWN due to collimated wind SNR reverse shock crushing into PWN

H.E.S.S. Highlight: Pulsar Wind Nebulae

Preliminary

Vela pulsar ROSAT contours  B. Khelifi, OG 22 Vela X hard spectrum G ≈1.9 or G ≈1.5  cutoff extends to 50 TeV no emission from vela pulsar detected

Another pulsar wind: MSH 15-52  B. Khelifi, OG 22 Photon index 2.27 ± 0.03 ± 0.20

Contours: Rosat Greyscale: Radio

HESS J1825-137 X-rays Gaensler et al.

TeV  O. de Jager, OG 22

H.E.S.S. Highlight: Distant and Close Binaries PSR B1259-63 3.4 year highly eccentric orbit around ~10 M  Be star closest approach ~10 13 cm or ~20 stellar radii Pulsar eclipsed Douglas Gies (CHARA, GSU) William Pounds

PSR B1259-63 first variable galactic TeV source  S. Schlenker, OG 22 HESS J1303-631 Feb. 04 PSR B1259-63 early March 04 Apr./May 04

Distant and

Close Binaries

 M. de Naurois, OG 22 with more data …

Microquasar LS 5039 first detection of TeV emission from a microquasar compact 4 (?) M around 20-30 M   object in eccentric 4 day orbit star closest approach ~10 12 cm or ~2 stellar radii Paredes J. M. et al., A&A 2002 RA (mas) fueled by wind accretion(?)

Spectral energy distribution Expect strong attenuation of gammas in photon field of massive star Hadronic component ?

Orbital modulation ??

Index 2.12 ± 0.15

The center of our Galaxy

PWN SNR G0.9+0.1

Sgr A East SNR ?

Black hole ?

DM Annihilation ?

GC

Sagittarius A syst. error Point-like core Colors: H.E.S.S.

Contours: Radio Extended tail Similar to NFW profile Angular distribution

Gamma ray spectrum  L. Rolland, OG 22 Preliminary

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)

Dark matter annihilation ?

10 -11

Preliminary

proposed based on early H.E.S.S. data 10 -12 10 -13 0,1 20 TeV Neutralino 20 TeV KK particle 1 E [TeV]  J. Ripken, OG 22 10 proposed before H.E.S.S. data

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

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

CS

(subtracted)

gamma rays

Extragalactic TeV astronomy

Physics of AGN jets Density of cosmological extragalactic background light (EBL)

x EBL x x

g VHE g EBL 

e + e -

H.E.S.S. Highlight: New distant blazar sources

1ES 1101-232 z = 0.186

~12

s Costamante & Ghisellini, 2002 2155 421 501 1426 1101 2356 2344 2005

Preliminary

H 2356-309 z = 0.165

~10

s   S. Pita, OG 23 M. Tluczykont, OG 23

Spectra & E xtragalactic B ackground L ight H 2356 (x 0.1) G = 3.1±0.2

EBL Source spectrum G = 1.5

1 ES 1101 G = 2.9±0.2

Preliminary

Spectra & E xtragalactic B ackground L ight H 2356 (x 0.1) G = 3.1±0.2

Source spectrum too much EBL  Upper limit on EBL 1 ES 1101 G = 2.9±0.2

Preliminary

Spectra & E xtragalactic B ackground L ight UV EBL H 2356 (x 0.1) G = 3.1±0.2

too much EBL 1 ES 1101 G = 2.9±0.2

Not really a solution: add huge amount of UV photons to EBL  problems with source energetics, X-ray/gamma-ray SED ratio

Preliminary

X X X



X



Spectra & E xtragalactic B ackground L ight upper limits

X X

measure ments

EBL resolved Universe more transparent Reference shape

lower limits from galaxy counts HESS limits

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, …