EVIDENCE FOR A STELLAR DISRUPTION BY AN INTERMEDIATE-MASS BLACK HOLE IN AN EXTRAGALACTIC GLOBULAR CLUSTER

We report [O III] lambda 5007 and [N II] lambda 6583 emission from a globular cluster harboring the ultraluminous X-ray source CXOJ033831.8-352604 in the Fornax elliptical galaxy NGC 1399. No accompanying Balmer emission lines are present in the spectrum. One possibility is that the forbidden lines emanate from X-ray-illuminated debris of a star that has been tidally disrupted by an intermediate-mass black hole, with this debris also feeding the black hole leading to the observed X-ray emission. The line strengths indicate that the minimum size of the emitting region is similar to 10(15) cm, and if the 70 km s(-1) half-widths of the emission lines represent rotation around the black hole, a minimum black hole mass of 1000 M-circle dot is implied. The non-detection of H alpha and H beta emission lines suggests a white dwarf star was disrupted, although the presence of strong nitrogen emission is somewhat of a mystery.