XMM-Newton Users Handbook

3.1 Basic characteristics

The most important characteristics of XMM-Newton are compiled in Table 1. More detailed numbers will follow in the chapters on the individual instruments (below) and a comparison with other X-ray satellites is provided in § 3.7. The basic characteristics of XMM-Newton are:

Table 1: XMM-Newton characteristics - an overview

Instrument	EPIC MOS	EPIC pn	RGS	OM
Bandpass	0.15-12 keV	0.15-15 keV	0.35-2.5 keV$^{~(1)}$	180-600 nm
Orbital target vis.$^{(2)}$	5-135 ks	5-135 ks	5-135 ks	5-145 ks
Sensitivity$^{(3)}$	$\sim$10$^{-14~(4)}$	$\sim$10$^{-14~(4)}$	$\sim$8$\times$10$^{-5~(5)}$	20.7 mag$^{~(6)}$
Field of view (FOV)	30'$^{~(7)}$	30'$^{~(7)}$	$\sim$5'	17'
PSF (FWHM/HEW)$^{(8)}$	5''/14''	6''/15''	N/A	1.4''-2.0''
Pixel size	40 $\mu$m (1.1'')	150 $\mu$m (4.1'')	81 $\mu$m (9$\times$10$^{-3}$ Å)$^{(9)}$	0.476513''$^{~(10)}$
Timing resolution$^{(11)}$	1.75 ms	0.03 ms	0.6 s	0.5 s
Spectral resolution$^{(12)}$	$\sim$70 eV	$\sim$80 eV	0.04/0.025 Å$^{(13)}$	350$^{~(14)}$

Notes to Table 1:
1) In the -1. grating order (wavelength range: 5-35 Å; $\lambda$ [Å] $\times$ E [keV] = 12.3984).
2) Total time available for science per orbit; minimum of 5 ks (excl. overheads, see § 4.5.2) in order to ensure observatory efficiency. XMM-Newton science observations can only be performed outside the Earth's radiation belts (see § 4.2.1).
3) After 10 ks; cf. overview tables on the individual instruments.
4) In the range 0.15-15.0 keV, in units of erg s$^{-1}$ cm$^{-2}$, see § 3.3.8 for details.
5) OVII 0.57 keV line flux in photons cm$^{-2}$ s$^{-1}$, for an integration time of 10 ks and a background of $10^{-4}$ photons cm$^{-2}$ s$^{-1}$ keV$^{-1}$. More details are provided in § 3.4.4.7.
6) 5-$\sigma$ detection of an A0 star in 1000 s.
7) See Figs. 17, 18 and 19 for the detailed shape of the FOV.
8) See Fig. 4 and 86 for an in-flight point source measurement for EPIC and OM, respectively. Table 2 lists in orbit and on ground PSF values for all three EPIC cameras separately.
9) In spectroscopy mode (standard $3\times3$ pixel on-chip binning applied).
10) $1''$ with $2\times2$ binning in default configuration mode. A higher resolution is achieved with the OM magnifier (not available in AO-8)
11) In fast data acquisition mode (i.e., fast mode for OM and timing mode for EPIC, spectroscopy mode for RGS, reading out only one of nine CCDs). The EPIC pn burst mode offers an even higher timing resolution of 7$\mu$s, but has a very low duty cycle of 3%.
12) At 1 keV energy. At the energy of Fe K$\alpha$ (6.4 keV), the energy resolution of both EPIC cameras is ca. 150 eV.
13) In -1. and -2. order, resp.; at 1 keV, this corresponds to 3.2/2.0 eV (HEW).
14) Resolving power $(\lambda/\Delta\lambda)$ with UV and optical grism.

• Simultaneous operation of all science instruments

  If not prohibited, e.g. by target brightness constraints, all six XMM-Newton science instruments operate simultaneously. They work independently (i.e., exposures of the individual instruments do not necessarily start and end at the same time).

• High sensitivity

  XMM-Newton carries the X-ray telescopes with the largest effective area of a focusing telescope ever: the total mirror geometric effective area at 1.5 keV energy is ca. 1550 cm$^2$ for each telescope, i.e., 4650 cm$^2$ in total.

• Good angular resolution

  XMM-Newton's high sensitivity is achieved by using 58 thin nested mirror shells in each X-ray telescope. The achieved point-spread function (PSF) has a full width at half maximum (FWHM) on the order of $6''$ and a HEW, at which 50% of the total energy are encircled, of ca. $15''$.

• Moderate and high spectral resolution

  The EPIC CCD cameras have moderate spectral resolution (with a resolving power, E/$\Delta$E, of ca. 20-50). The RGS spectrometers offer much higher spectral resolution, with a resolving power in the range of 200-800.

• Simultaneous optical/UV observations

  Observations with the co-aligned OM optical/UV telescope render possible the monitoring and identification of optical/UV counterparts of X-ray sources seen by the X-ray telescopes as well as imaging of the surrounding field.

• Long continuous target visibility

  A highly elliptical orbit offers continuous target visibility of up to about 40 hours, with a minimum height for science observations of 46,000 km. This is very favourable for studies of source variability and also in order to achieve a high overall observatory efficiency.

For a comparison of these basic characteristics with those of other past or contemporaneous X-ray satellite missions, see § 3.7.

More detailed information on the mirrors and on the instruments listed in Table 1 and their observing modes is provided in the following sections (§ 3.2 - § 3.5).