X-ray analysis Cheat Sheet
keV to erg 1 keV = 1.602 ×10−9erg
Plank constant h = 6.626 ×10−27 erg s
Exp time Tsec
Exp map (pix i,j) Eij cts photon−1sec cm2
Exp map (src avg) ES=X
S
Eij/X
S
1 cts photon−1sec cm2
≡Aeff T Effective area * Time
Effective area Aeff = 340 cm2(typical)
Src counts CSTotal cts in src reg cts
Bkg counts CBTotal cts in bkg reg cts
Net counts CN=CS−CBPSEij
PBEij
cts
Photon flux fp=CN/ESphotons cm−2sec−1
Energy flux f=fp·ECF erg cm−2sec−1
Energy band hν0,hν10.5, 8 keV
Power law spectrum fν=kνα≡kν1−Γerg cm−2sec−1Hz−1
Energy index αTypical = -0.7
Photon index Γ Typical = 1.7
Energy Conv Factor ECF = hν0
(ν1/ν0)α+1 −1
(ν1/ν0)α−1
α
α+ 1 erg photons−1
= 2.83 ×10−9erg photons−1
(E=0.5-8 keV, Γ = 1.7)
Redshift z
Luminosity L=Zν1
ν0
Lνdν erg
=Zν1/(1+z)
ν0/(1+z)4πd2
l·fνdν erg
=4πd2
l
(1 + z)α+1 ·ferg
=Kcorr ·4πd2
l·ferg
K correction Kcorr = (1 + z)Γ−2
Luminosity dist dl= (from cosmology calc) cm
