High energy perspectives
(and conclusions)
Philippe FerrandoAPC Laboratory (UMR 7164) - Service d’Astrophysique CEA/Saclay
APC Conference High Energy Phenomena in the Galactic Center June 17, 2005
The Galactic Centre : an exciting and growing field
Exciting :
• closest look we can have to a Super Massive Black Hole and its complex surroundings in the Universe - Potential link with more distant AGNs
• potentially harboring dark matter, UHE cosmic-ray accelerator…
Growing :
New high quality high energy data :
• X-rays [0.1–10 keV] Chandra & XMM–Newton 1999 -…
• -rays [0.02-10 MeV] Integral 2002 -
• TeV -rays [0.1–20 TeV] HESS 2003 -
Multi Wavelength Campaigns with radio and NIR
Chandra & XMM–Newton
Angular resolution :
resolving this complex region, and measuring the quiescent spectrum of SgrA*
High throughput : detailed spectro-imaging up to 10 keV
Chandra and XMM–Newton
Sensitivity : acces to short time variabilityG
alac
tic L
atitu
de
X-ray flares from SgrA*, look for periodicity…
INTEGRAL
Sensitivity and angular resolution : mapping this complex region
• IBIS/ISGRI mosaics in different energy bands: spectrum 20-120 keV
• Possible shift of the central source between Sgr A and 1E1743
20-30 keV
40-60 keV
30-40 keV
60-85 keV
HESSSensitivity, angular resolution, large Field of View
H.E.S.S. Preliminary
But questions still open…
What makes the 6.4 keV line ?
Nature of hot component ? Origin of the large scale 511 keV line ?
But questions still open…
IntegralIntegral
How many sources ? Spectrum of SgrA* ?
Are Ultra High Energy Cosmic Rays accelerated at the GC ?
What can we count on for sure ?
Gamma-ray sources and UHECR connection
AGASA excess map in the a posteriori energy band [1017.9 – 1018.3] eV
15°
GC
Completion in 2006 Unprecedented statistics expected
Angular resol. 0.5–1°
GC and AGASA/Sugar prime targets
?
AUGER
What can we count on for sure ?
Gamma-ray - Neutrinos connection
ANTARES
Completion in 2007
Max of signal expected @ ~ 10 TeV
Very low bckgd for point sources
Angular resol. @ 10 TeV ~ 0.2°
Expected rate (HESS) very low 0.02 evt/year
but surprises possible…
Clear need for a km3 experiment in a longer term
What can we count on for sure ?
AGILE gamma-ray telescope
Small ASI mission - launch date early 2006
Anticoincidence
SuperAGILE
Si tracker
Mini-Calorimetre
GRID : E-range : 30 MeV – 30 GeVFoV 2.5 sr 36 arcmin @ 1 GeV
Improve EGRET error box radius by a factor of 2
What can we count on for sure ?
GLAST/LAT EGRET
E range : 0.02 -300 GeV 0.02-30
E resolution : 10 % 10 %
Eff. Area : 8000 cm2 1500
Field of view > 2 sr 0.5 sr
Ang. Resol. ~ 3o @ 100 MeV 5.8°
~ 0.15o > 10 GeV
Sensitivity <6 x 10-9 cm-2 s-1 ~ 10-7
Source locat. 0.5 - 5 arcmin 5–30
The GLAST mission : launch mid 2007
Orders of magnitude improvement upon EGRET
What can we count on for sure ?
Upgrade : HESS II
• Lower threshold to extend the energy-range in mono-telescope mode
• Better sensitivity at high energies in stereo
Reduce GC source position uncertainty
now 4'' ± 10''stat ± 20''syst from Sgr A* (1 pc)
Atmospheric Cerenkov (stress on HESS but also MAGIC, VERITAS,
CANGAROO)
What can we count on for sure ?
Full spectral coverage in
gamma-rays !
• Connection space-ground
• Variability
And in a longer term ?
An absolute necessity : get the angular resolution and the sensitivity down by orders of magnitude above 10 keV
XMM-Newton GC Survey 0.3-9 keV0.0°
0.0°
0.0° 359.0°1.0°
INTEGRAL GC Survey 20-40 keV
(Bel
ange
r et
al 2
005,
in p
rep.
)
(
Dec
ourc
helle
et
al.
2003
)
Sgr A
Sgr B2
The 10 keV sensitivity gap reason
0.1–10 keV : focusing opticsSpatial resolution : 15 arcsecHigh signal to noise
XMM–Newton
15 keV–10 MeV : coded masksSpatial resolution : 12 arcminModerate signal to noise
INTEGRAL
The necessary future : use focusing optics as in longer wavelengths
In hard X-rays : feasible on a large energy range by extension of the « usual » soft X–rays techniques
Focusing using a grazing incidence nested shells Wolter I mirror
• Long focal length for high reflectivity at high energy
Projects NuSTAR and SIMBOL-X
Basically : long focal length telescope, using grazing incidence X–ray optics, with mirror and detectors mounted on two different spacecraft in formation flying.
Characteristics
Energy range :0.5–70 keV
Resolution : < 130 eV @ 6 keV, 1 % @ 60 keV
Angular resol. : < 30 arcsec (local. < 3 arcsec)
Effective area : > 550 cm2 E < 35 keV 150 cm2 @ 50 keV
Sensitivity : 5 10-8 ph/cm2/s/keV (E < 40 keV)
(5 , 100 ks, E = E/2)
The Simbol-X mission
Optics (nominal)
• Direct heritage from XMM–Newton
• Long focal length for high reflectivity at high energy
• Nickel shells with single layer Pt coating, obtained by well proven electroforming replication method
• Low mass obtained via a reduced thickness of shells
: ~ 30’’ HEWFOV : ~ 6 arcmin580 cm2 @ 30 keV
Shell diameters : 290 to 600 mmFocal length : 30 mAngles : 0.07° to 0.142°Shell thickness : 0.12 to 0.30 mmNumber of shells : 100Total mass : 213 kg
CdZnTe
SDD
< 17 keV > 17 keV
Low energy detector (450 m Silicium)
High energy detector (2 mm Cd(Zn)Te)
Optical filter (0.1 m Al)
Anticoincidence (BGO)
Requirements
• Pixel size of ~ 500 m (gives good oversampling of the 4.4 mm PSF)
• Full diameter of focal plane : 6 cm
• Fast response detectors for full anticoincidence scheme
• Avoid constraining cooling
• Low energy response down to 0.5 keV
• Good spectral resolution for Iron line
Focal plane
SDD CdZnTe
Sensitivity
1 arcmin diameter region, 1 Ms exposure, E = E/2
XMM INTEGRALSIMBOL-X
The central 2 degrees > 20 keV
today
1.0°
INTEGRAL GC Survey 20-40 keVSgr A
Sgr B2
0.0° 359.0°
in 2012with Simbol-
X
SIMBOL-X3 , 1 hour
Testing accretion models with SIMBOL-X
•Measurement of spectra for a large range of flare intensities
•Access to the high energy range, discriminating models
•Quiescent spectrum at ~ 40 keV
Liu & Melia, 2002
Galactic Centre Diffuse Emission
(Decourchelle et al. 04)
Galactic Centre seen by SIMBOL-X
Spectrum in a 1 arcmin2 regionExposure time = 84 ks
Simulation > 10 keV, 10 x 10 arcmin2
Total exposure = 300 ks
(A. Decourchelle & J. Ballet)
Simbol–X status
•Selected by CNES for phase 0 assessment (4 missions kept)
•Phase A start, autumn 2005 (2 missions kept)
•Selection end 2006 (1 mission kept)
•Consortium led by France with a strong Italian involvment, and a firm participation of Germany
•Mission proposed early 2004 to CNES in response to a call for scientific missions using spacecrafts in formation flying
•Launch date : 2012 - 2 years of science observations
Conclusions
The Galactic Centre
an exciting and growing field, with a rich future !
A lot of important results to come in the next years, but will not solve all questions
A deeper look possible early next decade with currently designed new generation of instruments