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)

(rollandl@in2p3.fr)

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