The discovery of 96 S pulsations from the variable X-ray source 1SAX J0544.1-710 in the Large Magellanic Cloud

We report the discovery of a ~ 96 s period X-ray pulsar in the direction of the Large Magellanic Cloud (LMC). The BeppoSAX X-ray spectrum is well fitted by an absorbed power-law model with photon index ~ 0.5. The unabsorbed luminosity in the 2-10 keV energy range is ~ 9x 10(35) erg s(-1) . The BeppoSAX position (40('') uncertainty radius) of \src\ was found to be consistent with that of the ASCA source AX J0448-70.4 and WGACAT (ROSAT PSPC) source 1WGA J0544.1-710. The source was detected four times between 1991 and 1996 at luminosity levels from ~ 3x 10(35) to 9x 10(35) erg s(-1) (2-10 keV), while during a relatively deep ROSAT HRI observation an extrapolated 2-10 keV luminosity upper limit of ~ 1x 10(35) erg s(-1) was obtained. Timing analysis of the ASCA data confirmed the BeppoSAX period discovery. Long-term flux variability is evident in the ROSAT and Einstein data. We revealed a pronounced Hα activity from a bright (V =~ 15) likely Be-type star within the 8\arcsec ROSAT PSPC error circle. Its optical spectrum shows it is located in the LMC. These results strongly suggest that \src\ is a transient X-ray pulsar in a massive binary system. Partially based on data collected with the ESO telescopes in La Silla