1998A&A...334L..65I

We analysed 13 archival ROSAT PSPC and HRI observations which included the position of a newly discovered 59s X-ray pulsar in the Small Magellanic Cloud, 1SAX J0054.9-7226 = 2E0053.2-7242. The source was detected three times between 1991 and 1996 at a luminosity level ranging from ∼8x10³⁴-4x10³⁵erg/s (0.1-2.4keV). Highly significant pulsations at 59.072s were detected during the 1991 October 8-9 observation. The ROSAT period, together with those measured by RXTE and BeppoSAX yields a period derivative of {dot}(P)=-0.016s/yr. A much more accurate source position (10" uncertainty) was obtained through the ROSAT HRI detection on 1996 April restricting to three m_V>15.5 stars the likely counterpart of 1SAX J0054.9-7226 = 2E0053.2-7242.