5. Symbols and quantities used in formulae

A or a

A(Ej) is the instrument effective area (cm2), i.e. the content of an OGIP format ARF file.
A lowercase a(E,x,y) indicates the mirror effective area

b (and Bi)

b(E,B1,B2) indicates an adimensional correction for Burst Length dependent effects as a function of BL thresholds Bi.

Ci

Count rate (cts/s alias cts/s/bin) in PHA or PI channel (or bin) i

dN/dE or S(E)

Photon input spectrum in photon/cm2/s/keV

Ej

Ej indicates the input photon energy (keV) on a discrete grid of j values
DeltaEj indicates the width of the j-th grid elements.

epsilon

Symbol epsilon indicates an adimensional quantum efficiency

f (and r)

f(E,r) indicates the fraction of PSF falling within an extraction radius r.

G

G(E) indicates the Gaussian component of the energy resolution.

P

Pij is the pure redistribution matrix, which is an adimensional probability. This is the content of an OGIP format RMF file.

Q

Qij is a less customary form of the overall response matrix which has the dimensions of cm2 keV. This is the form in which a response matrix is stored in XAS format.

R

R(i,E) or Rij indicates the overall response matrix (on a continuous or discrete energy scale), which has the dimensions of an area (cm2). This is the product of the RMF and ARF files.

T

T(E) indicates the non-Gaussian tail component of the energy resolution.

tau

Symbol tau indicates the adimensional transmission of a component like a filter, grid or window


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