A SURVEY FOR HIGHLY VARIABLE OBJECTS ON THE SRC-J PLATES .1. FAINT NEW CATACYLSMIC VARIABLES IN THE GALACTIC HALO

We present finding charts and spectra of seven new, faint (J approxima tely 19-21) cataclysmic variables discovered during a deep survey for highly variable objects in the overlapping regions of the SRC-J plates . Four of them are probably members of the halo population. The He II lambda4686 emission line is strong in two objects. One of them has bee n confirmed as a member of the AM Her class; its orbital period (2.66 h), well determined by photometry, spectroscopy, and polarimetry, lies within the period gap of CVs. The seven variables have relatively sma ll outburst amplitudes (1.6 mag on average), in contrast with most hig h latitude cataclysmics studied previously; this indicates that we sam ple a different sub-population of CVs than previous surveys which may suffer from selection effects.