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Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 1 Very high energy gamma-rays from the Galactic Centre measured by H.E.S.S. L. Rolland (CEA-Saclay/DSM/DAPNIA/SPP,

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Presentation on theme: "Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 1 Very high energy gamma-rays from the Galactic Centre measured by H.E.S.S. L. Rolland (CEA-Saclay/DSM/DAPNIA/SPP,"— Presentation transcript:

1 Loïc Rolland Gdr SUSY – Annecy, Octobre Very high energy gamma-rays from the Galactic Centre measured by H.E.S.S. L. Rolland (CEA-Saclay/DSM/DAPNIA/SPP, Gif-sur-Yvette, France) Observations of the Galactic Centre with H.E.S.S. Proposals for observations of Dwarf Galaxies

2 Loïc Rolland Gdr SUSY – Annecy, Octobre The 2004 signal: HESS J hours live time from March 30 to September 4, 2004 pointing within 2 degrees of Sgr A* 0° to 60° zenith angle <0.11° within Sgr A*:

3 Loïc Rolland Gdr SUSY – Annecy, Octobre HESS J Angular distribution Compatible with point-source in the very centre Tail at larger distance

4 Loïc Rolland Gdr SUSY – Annecy, Octobre HESS J Position and extension Assuming point-like source compatible with Sgr A* 5.6''±10''±20'' Diffuse emission Assuming symmetric gaussian distance to Sgr A* 3.9''±13''±20'' extension: 1.9' ± 0.23' 20 cm- VLA

5 Loïc Rolland Gdr SUSY – Annecy, Octobre Other high energy observations Compatibility with INTEGRAL source (G1) black hole Sgr A* supernova Sgr A East Incompatibility with unidentified EGRET source (99% CL)

6 Loïc Rolland Gdr SUSY – Annecy, Octobre HESS J Spectrum Energy range: 166 GeV-37 TeV Compatible with 2003 spectrum: =2.2±0.09±0.15 (>1TeV)=(2.0±0.4±0.3)x cm - 2 s -1 Search for exponential cut-off: E cut > 6 TeV (95% CL) 95% CL upper limits

7 Loïc Rolland Gdr SUSY – Annecy, Octobre HESS J Light curves Fit light curve by a constant: 2 probability projection of the reduced flux Night average flux 15% systematic errors added

8 Loïc Rolland Gdr SUSY – Annecy, Octobre HESS J Light curves Light curves compatible with constant flux 15% systematic errors added to every light curve points Sensitivity of the method for a 5 detection of a flare: nightly: x 2 28 minutes: x 4 10 minutes: x 7

9 Loïc Rolland Gdr SUSY – Annecy, Octobre Dark matter at the Galactic Centre ?

10 Loïc Rolland Gdr SUSY – Annecy, Octobre Shape of the DM halo Halo density profiles Extrapolations Predictions Large scale structure formation models

11 Loïc Rolland Gdr SUSY – Annecy, Octobre Gamma-ray: DM annihilation flux WIMP nature Neutralino annihilation lines are loop suppressed hadronisation (W ± and Z 0 ) Kaluza-Klein annihilation lines are loop suppressed charged leptons and quarks Dark matter halo Predicted gamma-ray annihilation flux: continuum MSSM Power law m KK = 10 TeV Cut-off

12 Loïc Rolland Gdr SUSY – Annecy, Octobre Gamma-ray: DM indirect detection WIMP nature DM halo shape Energy spectrum Angular distribution Predicted gamma-ray annihilation flux:

13 Loïc Rolland Gdr SUSY – Annecy, Octobre Only dark matter - Halo shape Cherenkov telescopes constraints DM halo shape Diffuse emission BUT Angular distribution compatible with cuspy halo ~ 1 Point-like source: > 1.2

14 Loïc Rolland Gdr SUSY – Annecy, Octobre Only dark matter - Spectrum shape Different spectra than Bergström and Profumo Misuse of PYTHIA ? Different spectra between Dark Susy and PYTHIA ?

15 Loïc Rolland Gdr SUSY – Annecy, Octobre Dark matter and astrophysical background 2 composonant spectrum: power law DM annihilation Spectrum compatible with power law Upper limits on.v Shape of the halo: NFW Uncertainties in density > 10 6

16 Loïc Rolland Gdr SUSY – Annecy, Octobre Dark matter and astrophysical background 99% CL upper limits ~10% of the gamma-rays from DM

17 Loïc Rolland Gdr SUSY – Annecy, Octobre Other DM candidates ?

18 Loïc Rolland Gdr SUSY – Annecy, Octobre H.E.S.S. Galactic survey (2004) HESS J HESS J HESS ° RX J HESS J HESS J HESS J ° HESS J HESS J HESS J LS 5039 HESS J Gal. Centre HESS J G HESS J HESS J HESS J ° 0° Sources > 6 sigma (9 new, 11 total) Sources > 4 sigma (7 new)

19 Loïc Rolland Gdr SUSY – Annecy, Octobre VHE unidentified sources Known (2003): TeV 2032 HEGRA Galactic Centre CANGAROO, Whipple, HESS, MAGIC Is there are new population of dark TeV emitters ?? Extended, structured Power law energy spectrum, photon index ~ New Sources (2005): J HESS J HESS J J Unconfirmed: 3EG J Milagro

20 Loïc Rolland Gdr SUSY – Annecy, Octobre Observation of dwarf galaxies

21 Loïc Rolland Gdr SUSY – Annecy, Octobre Sgr A Dwarf and Canis Major Sgr A Dwarf: 25 kpc Canis Major: 8 kpc Evans,Ferrer,Sarkar PRD (2004) For a NFW profile: GC - upper limits: ~4 gammas/hour from DM astrophysical parameters (mass, M/L etc) very uncertain

22 Loïc Rolland Gdr SUSY – Annecy, Octobre Predicted flux Assume: 50 backgrounds/hr NFW profile E thr = 100 GeV 1165CMajKK LKP CMajBest MSSM SgrDwKK LKP SgrDwBest MSSM SgrDwKK LKP SgrDwBest MSSM NN Exp (hr)TargetParticle model from Agnieszka's talk (Cherenkov 2005) Phi CMaj Phi SgrADw

23 Loïc Rolland Gdr SUSY – Annecy, Octobre Predicted results Detection Analyse spectrum+morphology Deeper exposure needed Non-detection Sgr A Dwarf (7.5 h) DM<10% GC Canis Major (5 h) DM< 3% GC

24 Loïc Rolland Gdr SUSY – Annecy, Octobre detection of HESS J in 2004 Position compatible with Sgr A* within 6'' Slightly extended ? = 1.8' Uncurved power law spectrum = 2.27 No indication of variability in Possible origin for the gamma-rays: Sgr A* Sgr A East stellar wind collisions cosmic-ray interactions in the dense medium dark matter annihilations

25 Loïc Rolland Gdr SUSY – Annecy, Octobre detection of HESS J in 2004 Pure DM annihilation spectrum incompatible with the data Loose constraints on.v in case of astrophysical background Looking for other DM source candidates: Sgr A Dwarf (25 kpc) Canis Major (8 kpc) GC not a good source to search for DM hours more observation in hours proposed for Similar results than GC in only ~5 h

26 Loïc Rolland Gdr SUSY – Annecy, Octobre VHE candidates at the Galactic Centre 4° × 5° A supermassive black hole: Sgr A*

27 Loïc Rolland Gdr SUSY – Annecy, Octobre In the vicinity of the black hole A supernova remnant Sgr A East 20 cm- VLA ~4x3 pc <1x1 pc

28 Loïc Rolland Gdr SUSY – Annecy, Octobre The GC seen by INTEGRAL keV keV 2° × 2°

29 Loïc Rolland Gdr SUSY – Annecy, Octobre Astrophysical candidates

30 Loïc Rolland Gdr SUSY – Annecy, Octobre Emission from Sgr A* Sgr A* : supermassive black hole variability energy spectrum

31 Loïc Rolland Gdr SUSY – Annecy, Octobre Emission from Sgr A East Sgr A East :supernova remnant extension energy spectrum

32 Loïc Rolland Gdr SUSY – Annecy, Octobre Emission from Sgr A East Sgr A East : supernova remnant extension energy spectrum

33 Loïc Rolland Gdr SUSY – Annecy, Octobre Other possibilities Cosmic-ray interaction with dense medium Collision of stellar winds Other contributions: transient sources observed in X-rays


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