Simultaneous X-ray and optical observations of the X-ray dip source X1755-338.
Abstract
Simultaneous X-ray and optical observations have been made of the 'dipping' X-ray source X1755-338 which has a dip recurrence period of 4.4 hr. A sinusoidal modulation of amplitude 0.4 mag is found in the V-band light of the 18 mag optical counterpart of the X-ray source. The period of the optical modulation is consistent with the X-ray dip recurrence period. The optical minimum occurs about 0.15 cycles after the centre of the X-ray dip. The optical modulation is probably caused by the changing aspect of an X-ray-heated companion star or an asymmetric disc. The X-ray data confirm that the dips in X1755-338 are shallow and not associated with photoelectric absorption. The most likely explanation for this remains that the elements responsible for absorbing 0.5 - 10.0 keV X-rays have a very low abundance in the material that obscures the X-ray source.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 1985
- DOI:
- 10.1093/mnras/216.4.1033
- Bibcode:
- 1985MNRAS.216.1033M
- Keywords:
-
- Optical Measurement;
- Spaceborne Astronomy;
- X Ray Binaries;
- X Ray Stars;
- Astronomical Photometry;
- Exosat Satellite;
- Light Modulation;
- Minima;
- Periodic Variations;
- Astrophysics