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X-ray data and analysis techniques

X-ray data and analysis techniques. Andreas Zezas Harvard-Smithsonian Center for Astrophysics. The complicated life of photons. Gas in the path. Source. Telescope + Instruments. X-ray sources. Compact objects accreting black-holes neutron stars etc jets Stars

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X-ray data and analysis techniques

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  1. X-ray data and analysis techniques Andreas Zezas Harvard-Smithsonian Center for Astrophysics

  2. The complicated life of photons • Gas in the path • Source • Telescope + Instruments

  3. X-ray sources • Compact objects • accreting black-holes • neutron stars etc • jets • Stars • Supernova remnants • Hot gas • galactic outflows, clusters of galaxies

  4. The complicated life of photons Telescope + Instruments http://chandra.harvard.edu/edu/chandra1017.html

  5. The complicated life of photons Telescope + Instruments • Instrument converts photon energy (E) to electric pulse Discretization converts electric pulse intensity to channel number (e.g. PI channel), pixel etc. http://chandra.harvard.edu/edu/chandra1017.html

  6. CDF-N Brandt etal, 2003 The complicated life of photons Telescope + Instruments • Instrumental effects: • Detection inefficiency • Blurring • image (PSF) • spectrum (RMF)

  7. The complicated life of photons Telescope + Instruments … or in other words • So from observed data D(PI) we want to recover S(E) • RMF, ARF are calibration data • Similar form for imaging data :

  8. S(E | sp. param.) RMF ARF Update parameter S_obs(E | sp. param.) 2 Accept / reject fit How we do it ?

  9. How we do it ? 2 statistic : convenient we understand it (we think) gives goodness of fit BUT requires Gaussian errors. C-statistic (or Cash statistic) works with Poisson data BUT does not give goodness of fit is not fully understood (e.g. bins with 0’s)

  10. What is S(E) ? atten, bbody, bbodyfreq, beta1d, beta2d, box1d, box2d, bpl1d, const1d, const2d, cos, delta1d, delta2d, dered, devaucouleurs, edge, erf, erfc, farf, farf2d, fpsf, fpsf1d, frmf, gauss1d, gauss2d, gridmodel, hubble, jdpileup, linebroad, lorentz1d, lorentz2d, nbeta, ngauss1d, poisson, polynom1d, polynom2d, powlaw1d, ptsrc1d, ptsrc2d, rsp, rsp2d, schechter, shexp, shexp10, shlog10, shloge, sin, sqrt, stephi1d, steplo1d, tan, tpsf, tpsf1d, usermodel, xs, xsabsori, xsacisabs, xsapec, xsbapec, xsbbody, xsbbodyrad, xsbexrav, xsbexriv, xsbknpower, xsbmc, xsbremss, xsbvapec, xsc6mekl, xsc6pmekl, xsc6pvmkl, xsc6vmekl, xscabs, xscemekl, xscevmkl, xscflow, xscompbb, xscompls, xscompst, xscomptt, xsconstant, xscutoffpl, xscyclabs, xsdisk, xsdiskbb, xsdiskline, xsdiskm, xsdisko, xsdiskpn, xsdust, xsedge, xsequil, xsexpabs, xsexpdec, xsexpfac, xsgabs, xsgaussian, xsgnei, xsgrad, xsgrbm, xshighecut, xshrefl, xslaor, xslorentz, xsmeka, xsmekal, xsmkcflow, xsnei, xsnotch, xsnpshock, xsnsa, xsnteea, xspcfabs, xspegpwrlw, xspexrav, xspexriv, xsphabs, xsplabs, xsplcabs, xsposm, xspowerlaw, xspshock, xspwab, xsraymond, xsredden, xsredge, xsrefsch, xssedov, xssmedge, xsspline, xssrcut, xssresc, xssssice, xsstep, xstbabs, xstbgrain, xstbvarabs, xsuvred, xsvapec, xsvarabs, xsvbremss, xsvequil, xsvgnei, xsvmcflow, xsvmeka, xsvmekal, xsvnei, xsvnpshock, xsvphabs, xsvpshock, xsvraymond, xsvsedov, xswabs, xswndabs, xsxion, xszbbody, xszbremss, xszedge, xszgauss, xszhighect, xszpcfabs, xszphabs, xszpowerlw, xsztbabs, xszvarabs, xszvfeabs, xszvphabs, xszwabs, xszwndabs (Sherpa models)

  11. What is S(E) ? • Power-law accreting sources, jets synchrotron emission (relativistic electrons in magnetic fields) • Thermal plasma (hot gas) Line emission measure temperature, density, pressure, metal content

  12. What is S(E) ?

  13. Z = 0.25 Z Z = 1.0 Z kT = 0.8 keV kT = 2.5 keV kT = 6.0 keV

  14. So what is S(E) Baldi etal, 2005, in press

  15. So what is S(E) Zezas etal, 2005

  16. Prestwich et al, 2003 Spectra : few counts • Few counts: Use hardness ratio • Ratio (in various flavors) of intensity in two bands, e.g. : • , , • Problems : • HRs in the Poisson regime (T. Park) • Separate source populations in HR diagrams (mixing etc) • Determine confidence intervals for spectral parameters

  17. Why all the fuss ? Thermal plasma : Temperature can constrain properties of the source Abundance provides clues to its history Line emission : DEM can constrain models for emitting regions of stars Relativistic FeKa line provides clues on black-hole physics Black-body : Temperature can constrain the nature of compact objects (neutron stars, quark stars, black-holes) Absorption : Given information on the nature of the intervening gas

  18. Spatial analysis • Goals : • Separate point-like from extended sources • Measure the parameters of extended component

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