Discovery of a new 170 s X-ray pulsar 1SAX J1324.4-6200

Abstract

We report the discovery with BeppoSAX of a new 170.84 +/- 0.04 s X-ray pulsar, 1SAX J1324.4-6200, found serendipitously in the field of the X-ray binary X1323-619 in 1997 August. The source and periodicity are also detected in archival ASCA data taken in 1994. The X-ray spectrum is modeled by a power-law with a photon index of 1.0 +/- 0.4 and absorption of (7.8 +2.7 -1.1) 10^22 atom cm-2. The source is located close to the galactic plane and within 3 arcmin of the direction of the dark cloud DC 306.8+0.6. The measured interstellar absorption and cloud size imply a distance >3.4 kpc. This implies a 1-10 keV source luminosity of >1.1 10^34 erg/sec during the BeppoSAX observation. The source is not detected in earlier Einstein IPC and EXOSAT CMA observations, most probably due to reduced detector efficency and lower sensitivity to highly absorbed sources. The X-ray properties suggest that 1SAX J1324.4-6200 is an accreting neutron star with a Be star companion.