Multiwaveband studies of the hard ROSAT SMC transient 1WGA J0053.8-7226: a new X-ray pulsar
Abstract
We report on two optical candidates for the counterpart to an X-ray source in the Small Magellanic Cloud, 1WGA J0053.8-7226, identified as a serendipitous X-ray source from the ROSAT Position Sensitive Proportional Counter (PSPC) archive, and also observed by the Einstein Imaging Proportional Counter. Its X-ray properties, namely the hard X-ray spectrum, flux variability and column density, indicate a hard, transient source, with a luminosity of ~ 3.8×1035ergs-1. XTE and ASCA observations have confirmed the source to be an X-ray pulsar, with a 46-s spin period. Our optical observations reveal two possible candidates within the error circle. Both exhibit strong Hα and weaker Hβ emission. The optical colours indicate that both objects are Be-type stars. The Be nature of the stars implies that the counterpart is most likely a Be/X-ray binary system. Subsequent infrared (IR) photometry (JHK) of one of the objects shows that the source varies by at least 0.5mag, while the (J-K) measured nearly simultaneously with the UBVRI and spectroscopic observations indicate an IR excess of ~0.3mag.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2001
- DOI:
- 10.1046/j.1365-8711.2001.03982.x
- arXiv:
- arXiv:astro-ph/0008486
- Bibcode:
- 2001MNRAS.320..281B
- Keywords:
-
- BINARIES: GENERAL;
- STARS: EMISSION-LINE;
- BE;
- PULSARS: GENERAL;
- INFRARED: STARS;
- X-RAYS: STARS;
- Astrophysics
- E-Print:
- Accepted for publication in MNRAS