We present optical candidates for 75 X-ray sources in a \sim 1 
deg ^ { 2 } overlapping region with the medium deep ROSAT survey ( Molthagen et al .
1997 ) .
These candidates are selected using the multi-color CCD imaging observations made for the T329 field of the Beijing-Arizona-Taipei-Connecticut ( BATC ) Sky Survey , which utilizes the NAOC 0.6/0.9m Schmidt telescope with 15 intermediate-band filters covering the wavelength range 3360-9745 Å .
These X-ray sources are relatively faint ( CR < < 0.2 s ^ { -1 } ) and thus mostly are not included in the RBS catalog , they also remain as X-ray sources without optical candidates in a previous identification program carried out by the Hamburg Quasar Survey .
Within their position-error circles , almost all the X-ray sources are observed to have one or more spatially associated optical candidates within them down to the magnitude m _ { V } \sim 23.1 .
We have classified 149 of 156 detected optical candidates with 73 of the 75 X-ray sources with a new method which predicts a redshift for non-stellar objects , which we have termed the SED-based Object Classification Approach ( SOCA ) .
These optical candidates include : 31 QSOs , 39 stars , 37 starburst galaxies , 42 galaxies , and 7 “ just ” visible objects .
Twenty-eight X-ray error circles have only one visible object in them : 9 QSOs , 3 normal galaxies , 8 starburst galaxies , 6 stars , and two of the “ just ” visible objects .
We have also cross-correlated the positions of these optical objects with NED , the FIRST radio source catalog and the 2MASS catalog .
Separately , we have also SED-classified the remaining 6011 objects in our field of view .
Optical objects are found at the 6.5 \sigma level above what one would expect from a random distribution , only QSOs are over-represented in these error circles at greater than 4 \sigma frequency .
We estimate redshifts for all extragalactic objects , and find a good correspondence of our predicted redshift with the measured redshift ( a mean error of 0.04 in \Delta z .
There appears to be a supercluster at z \sim 0.3-0.35 in this direction , including many of the galaxies in the X-ray error circles are found in this redshift range .