A Search for Photo-ionized Absorbers in High Mass X-ray Binaries: 4U 1907+09

In order to further our understanding of the emitting and absorbing material inhighmass Xray binaries (HMXB) and the accretion states of the sources,wepropose a total of 30 ksec XMMNewton observation of 4U 1907+09 to be conductedas two 15 ksec observations at different binary phases.In two archival ASCA SISspectra of 4U 1907+09,we found evidence for the presence of 6.9 keV Fe XXVIabsorption features at around 2sigma confidence which will yield 5sigmadetection with EPIC pn CCDs and the modelling will allow the properties of aphotoionized absorber to be determined for the first time in a HMXB. Ourproposed observation at the chosen phases will for the first time determinespectra at low count rate levels over a factor of 100 difference from the source. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]