EPIC spectral quality

In Figs. 29-33 we display a series of Mekal model spectra at different energies, ranging from 0.1 to 10.0 keV, with successively increasing total photon numbers (from 500 to 20000 counts). These show which data quality can be reached for a given total number of counts. All model spectra have been produced with SciSim, feeding in a Mekal model spectrum produced with xspec, using the thin filter and the full window mode. For the 0.1 keV model, the MOS and pn cameras are compared directly (Figs. 29 and 30), while for all other energies only the MOS model spectra are displayed. No processing of the spectra (like e.g., background subtraction or rebinning) has been performed.

**Figure 29:** *Series of EPIC MOS model spectra of a Mekal thermal plasma with a temperature of 0.1 keV. From the bottom to the top, the total number of counts in the* **XMM** *passband (0.1-15 keV) increases from 500 to 20000.*
$\begin{figure} \begin{center} \leavevmode \epsfig{width=0.6\hsize, angle=270, file=figs/mos_mekal_00_1kev.eps} \end{center} \end{figure}$

**Figure 30:** *Series of EPIC pn model spectra of a Mekal thermal plasma with a temperature of 0.2 keV. From the bottom to the top, the total number of counts in the* **XMM** *passband (0.1-15 keV) increases from 500 to 20000.*
$\begin{figure} \begin{center} \leavevmode \epsfig{width=0.6\hsize, angle=270, file=figs/pn_mekal_00_1kev.eps} \end{center} \end{figure}$

**Figure 31:** *Series of EPIC MOS model spectra of a Mekal thermal plasma with a temperature of 0.5 keV. From the bottom to the top, the total number of counts in the* **XMM** *passband (0.1-15 keV) increases from 500 to 20000.*
$\begin{figure} \begin{center} \leavevmode \epsfig{width=0.6\hsize, angle=270, file=figs/mos_mekal_00_5kev.eps} \end{center} \end{figure}$

**Figure 32:** *Series of EPIC MOS model spectra of a Mekal thermal plasma with a temperature of 2.0 keV. From the bottom to the top, the total number of counts in the* **XMM** *passband (0.1-15 keV) increases from 500 to 20000.*
$\begin{figure} \begin{center} \leavevmode \epsfig{width=0.6\hsize, angle=270, file=figs/mos_mekal_02_0kev.eps} \end{center} \end{figure}$

**Figure 33:** *Series of EPIC MOS model spectra of a Mekal thermal plasma with a temperature of 10.0 keV. From the bottom to the top, the total number of counts in the* **XMM** *passband (0.1-15 keV) increases from 500 to 20000.*
$\begin{figure} \begin{center} \leavevmode \epsfig{width=0.6\hsize, angle=270, file=figs/mos_mekal_10_0kev.eps} \end{center} \end{figure}$

XMM Users' Handbook

EPIC spectral quality