Optical and X-ray observations of the low-mass X-ray binary EXO 0748-676

Abstract

view Abstract Citations (4) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Optical and X-Ray Observations of the Low-Mass X-Ray Binary EXO 0748-676 Thomas, Brian ; Corbet, Robin ; Augusteijn, Thomas ; Callanan, Paul ; Smale, Alan P. Abstract Optical and X-ray observations of EXO-676 in late March 1989 are presented. Our optical observations provide some support for the previously observed correlation between the mean optical brightness and light curve morphology. Unexpectedly, the mean X-ray and optical flux levels during this period do not reflect similar system states. The optical counterpart is found to be in an intermediate to low state, while X-ray data imply a bright (high) state. The changed relationship between optical and X-ray fluxes is evidence showing that EXO 0748-676 has possibly evolved. We fail to find correlated variability in simultaneous X-ray and optical observations. The lack of covariability is attributed to the limited simultaneous coverage of the source and/or significant geometric modulation in the optical light curve. Publication: The Astrophysical Journal Pub Date: May 1993 DOI: 10.1086/172624 Bibcode: 1993ApJ...408..651T Keywords: Light Curve; Light Emission; Visual Observation; X Ray Astronomy; X Ray Binaries; Light Modulation; Optical Properties; Astronomy; STARS: BINARIES: CLOSE; STARS: INDIVIDUAL ALPHANUMERIC: EXO 0748-676; X-RAYS: STARS full text sources ADS | data products SIMBAD (8)