From a Chandra survey of nine interacting galaxy systems the evolution of X-ray emission during the merger process has been investigated .
It is found that the X-ray luminosity peaks \sim 300 Myr before nuclear coalescence , and then dips , even though we know that rapid and increasing activity is still taking place at this time .
It is likely that this drop in X-ray luminosity is a consequence of outflows breaking out of the galactic discs of these systems .
In this work it is also shown that , for the systems close to the point of nuclear coalescence , L _ { \mathrm { FIR } } becomes massively enhanced compared to the X-ray luminosity of these systems .
We suggest that this enhancement may indicate a ‘ top heavy ’ IMF , with an enhanced fraction of massive stars .

At a time \sim 1 Gyr after coalescence , the merger-remnants in our sample are X-ray faint when compared to typical mature elliptical galaxies .
However , we do see evidence that these systems will start to resemble typical elliptical galaxies at a greater dynamical age , given the properties of the 3 Gyr system within our sample , supporting the idea that halo regeneration will take place within low L _ { \mathrm { X } } merger-remnants .

As a part of this survey , detailed Chandra observations for the double nucleus merger system Mkn 266 and the merger-remnant Arp 222 are presented for the first time .
With the Mkn 266 observation , in contrast to previous studies , we now have good spectral information of the individual components part-seen with the ROSAT HRI .
Additionally , the structure of the emission to the north of the system can clearly be distinguished and there is also a suggestion of some extension of X-ray emission to the south east of the nuclear region , indicating that this galaxy could just be on the verge of large-scale galactic winds breaking out .
Within Arp 222 an X-ray luminosity of 1.46 \times 10 ^ { 40 } erg s ^ { -1 } has been detected , this is the lowest value of L _ { \mathrm { X } } within our sample .
The diffuse gas of Arp 222 has been modelled with a temperature of 0.6 keV and , from CO observations it has been found to host very little molecular gas , indicating that , from current observations , Arp 222 does not resemble a mature elliptical .