IRAS FSC-15307- GRAVITATIONALLY LENSED SEYFERT OR CANNIBAL ELLIPTIC AT Z=0.93(3252 )

We present the highest spatial and spectral resolution near-infrared d ata to date of the similar to 10(13) h(-2) L(.) IRAS source FSC 15307 + 3252 at z = 0.93, apparently the most luminous galaxy in the known u niverse. Deep K-band (2.2 mu m) images taken in 0.''4 seeing at the W. M. Keck Telescope reveal three components: (A) a bright elliptical so urce with a compact nucleus, (B) a resolved circular companion separat ed from component A by 2.''0 (8 h(-1) kpc for q(0) = 0.5), and (C) a f aint irregular component 1.''7 from A. The surface brightness profile of F15307-A is well characterized by a de Vaucouleurs r(1/4) law with r(e) = 1.''4 +/- 0.''2 (6 h(-1) kpc), a size comparable to local giant ellipticals. The nucleus of component A is stellar in appearance with extended structure, possibly a second nucleus similar to 0.''5 away. Our 1.1-1.4 mu m spectrum of the F15307 system with a resolution of 33 0 km s(-1) shows strong emission Lines of [O I] lambda lambda 6300, 63 64; blended H alpha + [N II] lambda lambda 6548, 6583; and [S II] lamb da lambda 6716, 6731. The similar to 900 km s(-1) width of the forbidd en lines and the relative strengths of the emission lines are characte ristic of Seyfert 2 galaxies. The Ha line also has a broad (1900 km s( -1)) component. In light of the recent discovery that FSC 10214 + 4724 , previously the most luminous known galaxy, is a gravitationally lens ed system, we explore the possibility that F15307 is also lensed. Quan titative arguments are inconclusive, but aspects of F15307's morpholog y do suggest lensing; the system bears a strong resemblance to quadrup le-image gravitational lenses. On the other hand, given the r(1/4) pro file, the close companions, and the active nucleus, F15307 may in fact be a giant elliptical galaxy caught in the act of galactic cannibalis m, a scenario that could also account for its unparalleled luminosity.