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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, Gif-sur-Yvette, France)
Observations of the Galactic Centre with H.E.S.S.
Proposals for observations of Dwarf Galaxies
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 2
The 2004 signal: HESS J1745-290
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*:
● 38
● 1862
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 3
HESS J1745-290 - Angular distribution
Compatible with point-source in the very centre
Tail at larger distance
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 4
HESS J1745-290 - 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' 20 cm- VLA
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 5
Other high energy observations
Compatibility with
● INTEGRAL source (G1)
● black hole Sgr A*
● supernova Sgr A East
Incompatibility with
● unidentified EGRET source (99% CL)
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 6
HESS J1745-290 - Spectrum
Energy range:
166 GeV-37 TeV
Compatible with 2003 spectrum:
=2.2±0.09±0.15
(>1TeV)=(2.0±0.4±0.3)x10-12 cm-2s-1
Search for exponential cut-off:
Ecut
> 6 TeV (95% CL)
95% CL
upper limits
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 7
HESS J1745-290 - 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 8
HESS J1745-290 - 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
Dataset P(Chi2) Sigmanightly 2003 73% 0.9 0.2nightly 2004 65% 1.0 0.1
nightly 2003-2004 50% 1.1 0.228-minutes 2004 41% 1.0 0.110-minutes 2004 94% 0.95 0.04
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 9
Dark matter at the Galactic Centre ?
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 10
Shape of the DM halo
Halo density profiles
Extrapolations
Predictions
Large scale structure formation models
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 11
Gamma-ray: DM annihilation flux
WIMP nature
Neutralino annihilationlines are loop suppressedhadronisation (W± and Z
0 )
Kaluza-Klein annihilation
lines are loop suppressedcharged leptons and quarks
Dark matter halo
● Predicted gamma-ray annihilation flux:
continuum MSSM
Power law mKK
= 10 TeV
Cut-off
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 12
Gamma-ray: DM indirect detection
WIMP nature DM halo shape
Energy spectrum Angular distribution
● Predicted gamma-ray annihilation flux:
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 13
Only dark matter - Halo shape
Cherenkov telescopes
constraints DM halo shape
Diffuse emission
BUT
Angular distributioncompatible with cuspy halo ~ 1
Point-like source:
> 1.2
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 14
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 15
Dark matter and astrophysical background
2 composonant spectrum:power lawDM annihilation
Spectrum compatible with power law
Upper limits on .v
● Shape of the halo: NFW
Uncertainties in density > 106
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 16
Dark matter and astrophysical background
99% CL upper limits
~10% of the gamma-rays from DM
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 17
Other DM candidates ?
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 18
H.E.S.S. Galactic survey (2004)
HESS J1702-420HESS J1713-381 HESS 1632-478
330°
RX J1713.7-3946HESS J1640-485
HESS J1616-508
HESS J1614-518
359°
HESS J1708-410 HESS J1634-472HESS J1745-303
LS 5039
HESS J1804-216 Gal. Centre HESS J1837-069
G0.9+0.1 HESS J1813-178 HESS J1825-137
HESS J1834-087
30° 0°
Sources > 6 sigma (9 new, 11 total)Sources > 4 sigma (7 new)
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 19
VHE unidentified sources
Known (2003): TeV 2032 HEGRAGalactic Centre CANGAROO, Whipple, HESS, MAGIC
Is there are new population of “dark” TeV emitters ??Extended, structuredPower law energy spectrum, photon index ~2.2 - 2.5
New Sources (2005):J1303-631 HESS J1614-518 HESS J1804-216 “ J1825-137 “
Unconfirmed:3EG J0520+255 Milagro
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 20
Observation of dwarf galaxies
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 21
Sgr A Dwarf and Canis Major
● Sgr A Dwarf: 25 kpc
● Canis Major: 8 kpc
75.05.0~2.01.0~ GC
CMaj
GC
Sgr
Evans,Ferrer,Sarkar
PRD 69 123501 (2004)
For a NFW profile:
GC - <v> upper limits: ~4 gammas/hour from DM
astrophysical parameters (mass, M/L etc) very uncertain
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 22
Predicted flux
Assume:− 50 backgrounds/hr− NFW profile−Ethr = 100 GeV
1165CMajKK LKP
243425CMajBest MSSM
0.367.5SgrDwKK LKP
5.6987.5SgrDwBest MSSM
0.83950SgrDwKK LKP
1365050SgrDwBest MSSM
NNExp (hr) TargetParticle model
from Agnieszka'stalk (Cherenkov 2005)
PhiCMaj
PhiSgrADw
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 23
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
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 24
38 detection of
HESS J1745-290
in 2004
Position compatible
with Sgr A* within 6'' Slightly extended ?= 1.8'
Uncurved power law spectrum = 2.27
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
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 25
38 detection of
HESS J1745-290
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...
50 hours more observation in 2005
50 hours proposed for 2006...
Similar results than GC
in only ~5 h
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 26
VHE candidates at the Galactic Centre
4° × 5°
A supermassive black hole:
Sgr A*
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 27
In the vicinity of the black hole
A supernova remnant
Sgr A East
20 cm- VLA
~4x3 pc
<1x1 pc
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 28
The GC seen by INTEGRAL
20-40 keV
40-100 keV
2° × 2°
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 29
Astrophysical candidates
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 30
Emission from Sgr A*Sgr A* : supermassive black hole
variability energy spectrum
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 31
Emission from Sgr A EastSgr A East :supernova remnant
extension energy spectrum
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 32
Emission from Sgr A EastSgr A East : supernova remnant
extension energy spectrum
Source Photon index Luminosity (10̂ {34} erg/s) distance (kpc)
Crab 2,6 9 2
G0.9+0.1 2,3 4 8,5
MSH15-5-2 2,3 10 5
CG 2.3 12 8.5
Loïc Rolland Gdr SUSY – Annecy, Octobre 2005 33
Other possibilities
● Cosmic-ray interaction with dense medium
● Collision of stellar winds
● Other contributions:● transient sources observed in X-rays