We present a multi-object optical spectroscopy follow-up study of X-ray sources in a field along the Galactic Plane ( l = 327.42 ^ { \circ } , b = 2.26 ^ { \circ } ) which is part of the Chandra Multi-wavelength Plane survey ( ChaMPlane ) .
We obtained spectra for 46 stars , including 15 likely counterparts to X-ray sources , and sources showing an H \alpha color excess .
This has led to the identification of a new cataclysmic variable ( CV ) , CXOPS J154305.5-522709 , also named ChaMPlane Bright Source 7 ( CBS 7 ) , and we identified 8 X-ray sources in the field as active late-type stars .
CBS 7 was previously studied in X-rays and showed a hard spectrum and two periods : 1.22 \pm 0.08 h and 2.43 \pm 0.26 h. We present here clear evidence that the source is a CV through the detection of H , HeI and HeII emission lines in its optical spectrum .
The hard X-ray spectrum and the presence of the HeII \lambda 4686 in emission with a large equivalent width suggest a magnetic CV .
The near-infrared counterpart is significantly variable , and we found a period consistent with the longest X-ray period at 2.39 \pm 0.05 h but not the shortest X-ray period .
If this period is the orbital period , this would place the system in the CV period gap .
The possible orbital period suggests a dM4 \pm 1 companion star .
The distance is then estimated to be \sim 1 kpc .
The system could be a relatively hard and X-ray luminous polar or an intermediate polar , possibly nearly-synchronous .