Very high energy gammarays from the Galactic Centre

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 (rollandl@in 2 p 3. fr) Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 1

The 2004 signal: HESS J 1745 -290 48 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*: Loïc Rolland ● 38 ● 1862 Gdr SUSY – Annecy, Octobre 2005 2

HESS J 1745 -290 - Angular distribution Compatible with point-source in the very centre Tail at larger distance Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 3

HESS J 1745 -290 - 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' Loïc Rolland 20 cm- VLA Gdr SUSY – Annecy, Octobre 2005 4

Other high energy observations Compatibility with ● INTEGRAL source (G 1) ● black hole Sgr A* ● supernova Sgr A East Incompatibility with ● unidentified EGRET source (99% CL) Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 5

HESS J 1745 -290 - Spectrum Energy range: 166 Ge. V-37 Te. V Compatible with 2003 spectrum: 95% CL upper limits =2. 2± 0. 09± 0. 15 (>1 Te. V)=(2. 0± 0. 4± 0. 3)x 10 -12 cm-2 s -1 Search for exponential cut-off: Ecut > 6 Te. V (95% CL) Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 6

HESS J 1745 -290 - Light curves Fit light curve by a constant: 2 probability projection of the reduced flux Night average flux 15% systematic errors added Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 7

HESS J 1745 -290 - Light curves 15% systematic errors added to every light curve points Light curves compatible with constant flux Sensitivity of the method for a 5 detection of a flare: nightly: x 2 28 minutes: x 4 10 minutes: x 7 Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 8

Dark matter at the Galactic Centre ? Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 9

Shape of the DM halo Large scale structure formation models Halo density profiles Predictions Extrapolations Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 10

Gamma-ray: DM annihilation flux ● Predicted gamma-ray annihilation flux: Dark matter halo WIMP nature Neutralino annihilation lines are loop suppressed hadronisation (W± and Z 0 ) Kaluza-Klein annihilation Power law lines are loop suppressed charged leptons and quarks Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 m. KK = 10 Te. V continuum MSSM Cut-off 11

Gamma-ray: DM indirect detection ● Predicted gamma-ray annihilation flux: Energy spectrum WIMP nature Loïc Rolland Angular distribution DM halo shape Gdr SUSY – Annecy, Octobre 2005 12

Only dark matter - Halo shape Angular distribution compatible with cuspy halo a~1 Cherenkov telescopes constraints DM halo shape Diffuse emission Point-like source: BUT Loïc Rolland a > 1. 2 Gdr SUSY – Annecy, Octobre 2005 13

Only dark matter - Spectrum shape Different spectra than Bergström and Profumo Misuse of PYTHIA ? Different spectra between Dark Susy and PYTHIA ? Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 14

Dark matter and astrophysical background 2 composonant spectrum: power law DM annihilation ● Shape of the halo: NFW Uncertainties in density > 106 Spectrum compatible with power law Upper limits on . v Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 15

Dark matter and astrophysical background 99% CL upper limits ~10% of the gamma-rays from DM Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 16

Other DM candidates ? Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 17

H. E. S. S. Galactic survey (2004) HESS J 1837 -069 HESS J 1834 -087 Gal. Centre HESS J 1804 -216 HESS J 1825 -137 HESS J 1813 -178 G 0. 9+0. 1 30° 0° LS 5039 HESS J 1745 -303 HESS J 1713 -381 HESS J 1702 -420 HESS J 1708 -410 HESS 1632 -478 HESS J 1634 -472 330° 359° RX J 1713. 7 -3946 Sources > 6 sigma (9 new, 11 total) Sources > 4 sigma (7 new) Loïc Rolland HESS J 1614 -518 HESS J 1640 -485 HESS J 1616 -508 Gdr SUSY – Annecy, Octobre 2005 18

VHE unidentified sources Known (2003): Te. V 2032 Galactic Centre HEGRA CANGAROO, Whipple, HESS, MAGIC New Sources (2005): J 1303 -631 HESS J 1614 -518 HESS J 1804 -216 “ J 1825 -137 “ Unconfirmed: 3 EG J 0520+255 Milagro Is there are new population of “dark” Te. V emitters ? ? Extended, structured Power law energy spectrum, photon index ~2. 2 - 2. 5 Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 19

Observation of dwarf galaxies Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 20

Sgr A Dwarf and Canis Major ● Sgr A Dwarf: 25 kpc ● Canis Major: 8 kpc astrophysical parameters (mass, M/L etc) very uncertain For a NFW profile: Evans, Ferrer, Sarkar PRD 69 123501 (2004) GC - < v> upper limits: ~4 gammas/hour from DM Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 21

Predicted flux Assume: − 50 backgrounds/hr − NFW profile −E thr = 100 Ge. V Phi. CMaj = 4 Phi. Sgr. ADw N N Sgr. Dw 50 650 13 KK LKP Sgr. Dw 50 39 0. 8 Best MSSM Sgr. Dw 7. 5 98 5. 6 KK LKP Sgr. Dw 7. 5 6 0. 3 Best MSSM CMaj 5 342 24 KK LKP CMaj 5 16 1 Particle model Target Best MSSM Loïc Rolland Exp (hr) Gdr SUSY – Annecy, Octobre 2005 from Agnieszka's talk (Cherenkov 2005) 22

Predicted results ● ● Detection ● Analyse spectrum+morphology ● Deeper exposure needed Non-detection ● ● Loïc Rolland Sgr A Dwarf (7. 5 h) DM<10% GC Canis Major (5 h) DM< 3% GC Gdr SUSY – Annecy, Octobre 2005 23

38 detection of HESS J 1745290 in 2004 Loïc Rolland Position compatible with Sgr A* within 6'' Uncurved power law spectrum = 2. 27 Slightly extended ? = 1. 8' No indication of variability in 2003 -2004 Possible origin for the gamma-rays: ● Sgr A* ● Sgr A East ● stellar wind collisions ● cosmic-ray interactions in the dense medium ● dark matter annihilations Gdr SUSY – Annecy, Octobre 2005 24

38 detection of HESS J 1745290 in 2004 Pure DM annihilation spectrum incompatible with the data Loose constraints on . v in case of astrophysical background GC not a good source to search for DM. . . 50 hours more observation in 2005 50 hours proposed for 2006. . . Looking for other DM source candidates: Sgr A Dwarf (25 kpc) Canis Major (8 kpc) Loïc Rolland Similar results than GC in only ~5 h Gdr SUSY – Annecy, Octobre 2005 25

VHE candidates at the Galactic Centre A supermassive black hole: Sgr A* 4° × 5° Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 26

In the vicinity of the black hole A supernova remnant Sgr A East ~4 x 3 pc 20 cm- VLA <1 x 1 pc Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 27

The GC seen by INTEGRAL 2° × 2° 20 -40 ke. V 40 -100 ke. V Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 28

Astrophysical candidates Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 29

Emission from Sgr A* : supermassive black hole variability energy spectrum Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 30

Emission from Sgr A East : supernova remnant extension energy spectrum Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 31

Emission from Sgr A East : supernova remnant extension energy spectrum Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 32

Other possibilities ● Cosmic-ray interaction with dense medium ● Collision of stellar winds ● Other contributions: ● Loïc Rolland transient sources observed in X-rays Gdr SUSY – Annecy, Octobre 2005 33