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	0.15-12 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 0.15-12.0 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 102 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.
11) In fast data acquisition mode (i.e., fast mode for OM and timing mode for EPIC, spectroscopy mode for RGS1 [1.2 s for RGS2], 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).