2 Specific Issues of X-ray Astronomy Earth atmosphere is opaque to X-rays => balloons, rockets or satellites neededOptics: difficult or even impossible to focalize X-raysDetectors of Photoelectric and Compton interactionsSources have intrinsically weak photon fluxes (non-thermal spectra or HE tail of thermal very hot medium)Detectors sensitive to particles and particle-generated X-rays => high level of background => Low S/N ratios
3 The early days of X-ray Astronomy X-ray astronomy starts after the WW II1962 discovery of the 1st extra-solar X-ray source with Sounding Rocket det1970 First X-ray satelliteUhuruInstruments based on Proportional Counters + collimatorsEnd of ’70s :focusing telescopes
4 Focalisation of Soft X-rays X and gamma - raysradio, IR,visible, UVwavesSoftX - raysJacques PaulPlanche 4L’observatoire spatial INTEGRAL – Lycée Arago – Perpignan
5 X-ray Grazing incidence reflection Since EX > Eebind then refraction index for X-rays nX < 1 => it exists an incident angle of total external reflection (grazing angle) given by cos θr = nXFor nX = (1-δ), θr = (2δ)½ with δ = N0Zreρλ2/A 2π(e.g. Giacconi+ 69)For Heavy Elements Z/A ~ 0.5 and thereforeθr ρ1/2/ EXGood reflectors are Au, Ni, Ir, Pt and critical angle are in the range 10’ - 2° for X-rays of 0.1 to 10 keV
6 WOLTER Type I X-ray Mirror System 1 Paraboloid + 1 Hyperboloid polished and coated mirrorsEmax = k f/D keVfor D=1 m diameter & f=10 m focal length => Emax~ 10 keV
8 A Focusing X-ray Telescope Several nested W-I mirrors and coated in Ni, Au or Ir focalize grazing incident X-raysInto a focal plane position sensitive detector, e.g. a CCD for X-raysImages are formed with effective area given by nested mirrors and a low background that depends on the detector volume.
9 Major Mirror X-ray Telescopes (untill 2000) 1999
11 XMM Optical System and the Reflection Grating Spectrometer 70 cm58 mirror shells0.5 – 1 mm thick
12 Images from XMM Newton EPIC Observations: stabilized pointing of target sources for typical exposures of ksData are in form of event lists (x, y, t, E)Analysis: correct, filter, bin and combine event lists into images, spectra, light curves, and then derive source parameters.
13 Imaging performances of XMM 110”Images of a point source by the 3 EPIC cameras (MOS1 MOS2 and PN)PSF as function of distance from source:6" (FWHP), 15" (HEW)
14 XMM PerformancesEffective area of XMM mirrors plus focal plane instrumentsTypical spectra otained with XMM EPICCalibration +background spectrum with XMM EPIC PN
16 The concept of a Pinhole camera And … for E > keV ?The concept of a Pinhole camera
17 The concept of Coded Mask Imaging source à l’infinimasque codédétecteur sensibleà la position
18 source 1masque codédétecteur sensibleà la position
19 source 2masque codédétecteur sensibleà la position
20 The ESA INTEGRAL Mission A Gamma Ray Observatory2 main -ray TelescopesEnergy: 15 keV – 8 MeVHigh angular res.: ~ 12’ (IBIS)High spectral Res: DE/E ~=500(SPI)+ 2 Monitors (opt, X)Launched with a Proton on 17/10/2002The First Gamma-Ray OBSERVATORY for the Astronomical Community
21 SPI γ-ray spectrometer IBIS / ISGRI PerformancesEnergy Band keV-1 MeVAngular Resolution 12’FOV at 100% s. 9° x 9°at 0 sensitivity ° x 29°Point Source Location Err ” (S/N~30)Temporal resolution s100 keVSensitivity (ph cm-2 s-1 keV-1)(for 106 s, 3, E=E) 1 mCrabNarrow line sens. (cm-2 s-1) 10-5Spectral resolution keVOMC (visible band)IBIS γ-ray imagerJEM-X (X-ray monitor)ISGRI cameraSPI γ-ray spectrometer
28 XMM-Newton GC Survey 0.3-9 keV INTEGRAL GC Survey Sgr A 20-40 keV 0.0°XMM-Newton GC Survey0.3-9 keV0.0°(Belanger et al. 2006) (Decourchelle et al. 2003)INTEGRAL GC SurveySgr A20-40 keVSgr B20.0°1.0°359.0°
29 INTEGRAL / SPI 511 keV Line Spherical shape (Bulge) 2D Gaussian profile with FWHM ~ 8ºPositronium fraction:Annihilation in warm ionized mediumOrigin of positrons unknownOriginated at the GC ?(Knodelseder et al. 2004, Churazov etal 04, Jean etal 2005, ..)Centroid:/-0.10 keVLine width:/-0.51 keV (FWHM)Flux:(1.05±0.06)×10-3 ph cm-2 s-1
30 Perspectives and Future Missions Focalization at E > 10 keV, using multilayer coating + long focal L (> 10 m) with extendable mats or formation flying:Nu-Star (US, 2013) Astro-H (JAXA, +, 2014): Emax ~ 80 keV but Ang.Res > 40’Several non-selected EU projects: Simbol-X (F-I), COSPIX (M3), NHXM (M3)Focal-Plane Micro-calorimeters for high spectral res.: Astro-H (and IXO)Light mirrors (glass layers, silicon pore layers) to obtain large effective areas and sensitivities (IXO)Small / medium missions: X-ray polarimeters (GEM US 2014) or Large sensitive areas for timing / spectral studies (LOFT)Coded masks for HE monitoring of transients and GRBs (SVOM Ch – F 2014)Compton telescopes and Bragg diffusion lenses (M3) for the 1 MeV range.
31 X-Ray Astronomy Programmatics Chandra, XMM-Newton, INTEGRAL missions extended to 2014Nu-Star, Astro H, SRG, GEM in development phaseIXO delayed by US Decadal to after 2025In competition for ESA Cosmic Vision Large class Mission (decision 2011)No HE mission in the ESA Medium class Missions M1/M2 Missions (Launch 2018)1 HE mission selected for the ESA M3 call (L 2020): LOFT
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