XMM EPIC MOS Steve Sembay Mallorca 01/04/09 A Phenomenological approach to the MOS detector response. Steve Sembay Phenomenological Theory. A theory which expresses mathematically the results of observed phenomena without paying detailed attention to their fundamental significance. i.e. If you don't understand it....describe it !

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Motivation: Develop a descriptive model of the RMF that is computationally quick to generate and provides a “reasonably” accurate description of the spatial and temporal variations observed in the MOS RMF (i.e. the patch) A “quick” RMF makes deriving RMF parameters via optimisation procedures practical and allows one to provide a description for changes to the RMF much more quickly than “manual tweaking” Such a model could be used to inform a more physically realistic model.

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 tnmin optimisation program in IDL IACHEC model for 1E0102 Automated RMF fitting

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 x (μm) f(x) f(x) = α + (β E 0 ) E(x) = f(x) E 0 I(e) = ∑I(x)exp(E(x),e,σ) dx α = α(E 0 ), β = β(E 0 ) Current Empirical Surface Loss Model

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Nov FM1 = Flight Spare“Calibrate Orsay” Apr 1998 – FM2 = MOS26 CCDs (1 faulty) Camera rebuild in June 1998 July 1998 – FM3 = MOS17 CCDs Nov 1998 – FM1 = Flight Spare7 CCDs Orsay MOS Calibration Campaign Data on 20 EPIC-MOS CCDs MOS1- All 7 CCDs in orbit have Orsay ground cal data MOS2- Due to rebuild, 4 CCDs in orbit have Orsay ground cal data

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 FM1MOS1MOS2FM1MOS1MOS2FM1MOS1MOS2 Orsay Data 20 CCDs E input = 350 eV

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 FM1MOS1MOS2FM1MOS1MOS2FM1MOS1MOS2 Orsay Data 20 CCDs E input = 350 eV

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Orsay Data 20 CCDs E input = 350 eV Re-order by strength of loss peak. “Good” “Bad” What if the way the shape changes from “good” to bad” from CCD to CCD (at a given energy) is similar to the way the shape of the loss peak in the patch changes with time on the central CCD (at that energy).

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Position and Size of Loss Component have relatively simple functional forms versus energy 0.73 MOS1 CCD1

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Position of loss peak / position of main peak Fraction of counts in loss peak These two quantities are correlated!

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Position of loss peak / position of main peak Fraction of counts in loss peak These two quantities are correlated!

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 The position of the loss peak relative to the main peak (The Epeak parameter) is constant with energy (at least above ~300 eV) The strength of loss peak follows a simple exponential relation with energy. The normalisation of this relation is correlated with Epeak. In this simple descriptive model, a single parameter, Epeak defines the position and strength of the loss peak as a function of energy.

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Descriptive Model: The VRMF Model Main Peak Blue Wing: Gaussian Red Wing: Voigt Function = Gaussian convolved with a Lorentian. Dampening factor = 0 (Gaussian) > 0 (Lorentz-like)

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Descriptive Model: The VRMF Model Loss Peak Blue Wing: Triangular Red Wing: Gaussian Time to generate 2400 x 2400 SAS p0 rmf ~ 60 seconds Time to generate 2400 x 2400 VRMF p0 rmf ~2 seconds

XMM EPIC MOS Steve Sembay Mallorca 01/04/ Comparing the Model to 1E0102 (MOS1)

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 IACHEC model for 1E0102 Automated RMF fitting Epeak σ = a + b*sqrt(E) Global Norm 4 Free Parameters

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 χ 2 (SAS)χ 2 (VRMF)Epeak Rev Rev Rev

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 χ 2 (SAS)χ 2 (VRMF)Epeak Rev Rev Rev

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 χ 2 (SAS)χ 2 (VRMF)Epeak Rev Rev Rev c.f. Orsay Epeak = 0.73

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Lines ~ keV too strong ?

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Conclusions: 1) It is possible to mathematically describe the energy dependent shape of the loss component of the RMF, as observed in our ground cal, with a model which has one dependent parameter = Epeak. (True > eV) 2) Deriving Epeak assuming the IACHEC 1E0102 model gives values consistent with that measured at Orsay for off-axis and consistent with our “picture” of the patch for on-axis. 3) What about low energies? Below ~ eV

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 The Curious Case of Konrad's Comet Obs: 3.29 cts/s Model: 3.33 cts/s χ 2 = Bad!

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 The Curious Case of Konrad's Comet Obs: 3.25 cts/s Model: 3.37 cts/s

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 The Curious Case of Konrad's Comet

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 The Curious Case of Konrad's Comet

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 The Curious Case of Konrad's Comet

XMM EPIC MOS Steve Sembay Mallorca 01/04/09 Orsay Data 20 CCDs E input = 350 eV Re-order by strength of loss peak. “Good” “Bad”