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P. Zhao, J. E. Grindlay, P. Edmonds, M. R. Garcia, J. E. McClintock (CfA), C. Bailyn (Yale), A. Cool (SFSU), H. Cohn, P. Lugger (Indiana U.), D. Hoard, S. Wachter (CTIO)
The Chandra Multiwavelength Plane (ChaMPlane) Survey is a project to identify a large sample of serendipitous X-ray sources in the galactic plane, including cataclysmic variables, quiescent low mass X-ray binaries (qLMXBs: in both black hole and neutron star systems), Be X-ray binaries and stellar coronal sources (see Grindlay et al 2000, BAAS, 196, 37.07 for general description). ChaMPlane has been chosen by NOAO as a Survey Program (awarded 31 nights over the next 5 years on the KPNO and CTIO 4m telescopes) for deep imaging. CVs and qLMXBs are identified by their ubiquitous H\alpha excess as ``blue'' objects in the R vs. (H\alpha - R) diagram. A pilot survey was successfully conducted at the CTIO 4m in March, 2000 with the newly installed MOSAIC-II CCD detector. Nine Chandra cycle-1 galactic fields were observed. Photometry down to 24th mag in the galactic plane was performed in the V, R, I and H\alpha bands. We will present our data analysis method and results from 3 overlapping Chandra fields towards the Galactic center. The MOSAIC images (36'\times36' FOV) are first CCD reduced; then astrometry is performed (using the new IRAF/MSCRED package) on each image enabling different but overlapping pointings to be stacked in groups by exposure times. DAOPHOT psf-photometry is performed on the stacked images. The H\alpha emission stars found within the Chandra field(s) (e.g., ACIS-I: 17'\times17' FOV) are finally compared with the ~arcsec Chandra source positions and fluxes for initial classification of objects in the EW(H\alpha) vs. Fx/Fv plane. Followup multi-object spectroscopy will be conducted on most candidates, with an initial run scheduled on WIYN in January 2001 for the northern fields. We anticipate that analysis of even the cycle-1 fields will provide significant new constraints on the number density of accretion-powered X-ray sources in the Galaxy.