부산대학교 도서관

We show that the black hole in the x-ray binary Cygnus X-1 was formed in situ and did not receive an energetic trigger from a nearby supernova. The progenitor of the black hole had an initial mass greater than 40 solar masses and during the collapse to form the ~10 solar mass black hole of Cygnus X-1, the upper limit for the mass that could have been suddenly ejected is ~1 solar mass, much less than the mass ejected in a supernova. The observations suggest that high-mass stellar black holes may form promptly, when massive stars disappear silently.
Comment: 8 pages, 1 color figure, PDF version only. Link to the comments article in Science Now: http://sciencenow.sciencemag.org/cgi/content/full/2003/424/2