Discovery of the Slowest X-Ray Pulsar in the SMC, AX J0049.5–7323, with ASCA

[摘要] ThediscoveryofcoherentpulsationswithASCAfromanX-raysource,AXJ0049.5−7323,isreported.Thebarycentricperiodwasdeterminedtobe755.5±0.6s,whichisthelongestamongX-raypulsatorsintheSMC.TheX-rayspectrumhasbeenfoundtobeunchangedthroughASCAobservations,withaphotonindexof∼0.8andaluminosityof∼5×1035ergs−1(0.7−10keV).ArchivaldataoftheEinsteinandtheROSATsatellitesindicatethatthefluxhasbeen≲10−12ergs−1cm−2(≲5×1035ergs−1)forover20yearsandexhibitsavariabilitywithafactorof≳10.WearguethatAXJ0049.5−7323isanX-raypulsarwithaBestarcompanion.

[学科分类] 天文学(综合)

[关键词] "pulsars: individual (AX J0049.5-7323)";"stars: emission-line;Be";"stars: neutron";"X-rays: stars"