The standard background 0.1-10.0 keV count rate in the
central 8 radius source extraction region is
s-1 keV-1 arcmin-2.
The dependence of the standard background count rate
on position within the FOV is
shown in the left panel of Fig. 3.
This image has been smoothed using
a Gaussian filter with a
of 4 RAW pixels. The difference in
intensity between the most and least intense regions
is a factor 1.8.
The X-ray background appears brighter close to the center of the
image due primarily to mirror vignetting. Note that
the LECS mirror axis is offset by 3
from the center of the FOV due to an alignment error during integration.
The two bright arcs are located
radially inwards from the 55Fe calibration sources and
result from 5.9 keV characteristic
X-rays that are absorbed some distance
from their origin.
![]() |
Figure 3:
The dependence of the LECS standard background (left panel) and
NXB (right panel) on
RAWX, RAWY position within the FOV. Gaussian smoothing
filters with a ![]() |
Figure 4 illustrates the overall shape of the
standard background spectrum obtained in the central 8 of the
FOV. The Non X-ray
background (NXB) obtained from the same region of the detector is also shown
(see Sect. 5).
The difference between the two is the contribution
of the cosmic X-ray background (CXB), spectral fits to which
are presented in a companion paper (Parmar et al. 1999).
![]() |
Figure 4:
Rebinned spectrum of the standard background (filled circles)
and the NXB (open circles) in the central 8![]() |
![]() |
Copyright The European Southern Observatory (ESO)