We present results of a monitoring campaign of the high-mass X-ray binary system 4U~1700 $ - $ 37 / HD~153919 , carried out with XMM- Newton in February 2001 .
The system was observed at four orbital phase intervals , covering 37 % of one 3.41-day orbit .
The lightcurve includes strong flares , commonly observed in this source .
We focus on three epochs in which the data are not affected by photon pile up : the eclipse , the eclipse egress and a low-flux interval in the lightcurve around orbital phase \phi \sim 0.25 .
The high-energy part of the continuum is modelled as a direct plus a scattered component , each represented by a power law with identical photon index ( \alpha \sim 1.4 ) , but with different absorption columns .
We show that during the low-flux interval the continuum is strongly reduced , probably due to a reduction of the accretion rate onto the compact object .
A soft excess is detected in all spectra , consistent with either another continuum component originating in the outskirts of the system or a blend of emission lines .
Many fluorescence emission lines from near-neutral species and discrete recombination lines from He- and H-like species are detected during eclipse and egress .
The fluorescence Fe K \alpha line at 6.4 keV is very prominent ; a second K \alpha line is detected at slightly higher energies ( up to 6.7 keV ) and a K \beta line at 7.1 keV .
In the low-flux interval the Fe K \alpha line at 6.4 keV is strongly ( factor \sim 30 ) reduced in strength .
In eclipse , the Fe K \beta /K \alpha ratio is consistent with a value of 0.13 .
In egress we initially measure a higher ratio , which can be explained by a shift in energy of the Fe K-edge to \sim 7.15 keV , which is consistent with moderately ionised iron , rather than neutral iron , as expected for the stellar wind medium .
The detection of recombination lines during eclipse indicates the presence of an extended ionised region surrounding the compact object .
The observed increase in strength of some emission lines corresponding to higher values of the ionisation parameter \xi further substantiates this conclusion .