THE DETECTION OF THE LAMBDA-2175 FEATURE AND FURTHER ANALYSIS OF THE BROAD ABSORPTION-LINE PROFILE STRUCTURE IN THE GRAVITATIONAL LENS CANDIDATE UM-425

We obtained Multiple Mirror Telescope spectra of the gravitational len s candidate UM 425 to compare the redshifts and line profile structure s of lens components A and B, which are separated by approximately 6 ' '.5. The C IV lambda 1550 emission in both A and B exhibits broad abso rption Line (BAL) structure, consistent with the earlier detection of BAL structure in O VI lambda 1033 and N V lambda 1240 that was found w ith the International Ultraviolet Explorer in component A. Cross-corre lation of the spectra of A and B using emission lines of C IV lambda 1 550, He II lambda 1640, N III lambda 1750, C III] lambda 1909, and Mg II lambda 2800 reveals a difference in the redshifts of A and B. Howev er, the detailed BAL profile structure found in the spectra of A and B are strikingly similar to one another, which suggests the system is l ensed. The spectra of A and B also indicate significant dust extinctio n, which we base on the presence of the lambda 2175 absorption feature in the rest frame of the QSO (z(QSO) = 1.47). This feature is commonl y seen in galactic sources but is not generally observed in QSO spectr a. Our spectra show the presence of the lambda 2175 absorption feature in spectra of both images associated with the gravitational lens UM 4 25. Based upon the strong similarity of BAL profile structure exhibite d by UM 425A and UM 425B, particularly the presence of the lambda 2175 dust absorption feature in spectra of both images, we conclude that U M 425 is a gravitational lens.