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Durham University

Department of Physics

Staff profile

Publication details for Prof Tim Roberts

Irwin, J.A., Brink, T.G. Bregman, J.N. & Roberts, T.P. (2010). Evidence for a Stellar Disruption by an Intermediate-mass Black Hole in an Extragalactic Globular Cluster. Astrophysical Journal Letters 712(1): L1-L4.

Author(s) from Durham


We report [O III] λ5007 and [N II] λ6583 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 ~1015 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 ☉ is implied. The non-detection of Hα and Hβ emission lines suggests a white dwarf star was disrupted, although the presence of strong nitrogen emission is somewhat of a mystery.