The Discovery of 8.9 Second Pulsations from the Variable X-Ray Source 2E 0050.1−7247 in the Small Magellanic Cloud
Israel, G. L. ; Stella, L. ; Angelini, L. ; ...Giommi, P. ; et al.
Aug - 1997
ISSN : 0004637X ;
journal : The Astrophysical Journal

Issue : 2
type: Article Journal

Abstract
During a systematic search for periodic signals in a sample of ROSAT PSPC light curves, we discovered 8.9 s X-ray pulsations in 2E 0050.1-7247, a variable X-ray source in the Small Magellanic Cloud. The source was detected several times between 1979 and 1993 at luminosity levels ranging from 5 × 10 34 ergs s -1 up to 1.4 × 10 36 ergs s -1 with both the Einstein IPC and ROSAT PSPC. The X-ray energy spectrum is consistent with a power-law spectrum that steepens as the source luminosity decreases. We revealed a pronounced H\alpha activity from at least two B stars in the X-ray error circles. These results strongly suggest that the X-ray pulsar 2E 0050.1-7247 is in a Be-type massive binary.

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