The paper ‘Rapid Optical Variations Correlated with X-rays in the 2015 Second Outburst of V404 Cygni (GS 2023+338)’ was published in MNRAS, 471, 373 (2017). In this paper, the observation times of X-ray light curves were measured at the satellite and their system of times was Terrestrial Time (TT), while those of optical light curves were measured at the Earth and their system of times was Coordinated Universal Time (UTC). We have converted the times of these light curves to the common time system BJD (TT) with the tool barycent in OSA, and made timedelay analyses. In addition, we have reduced the X-ray data again by using the updated version of the tool ii_shadow_build from the one in OSA v10.2. In calculating the background normalization in the imaging step, the affected pixels by the bright sources V404 Cyg, Cyg X-1, and Cyg X-3 were taken into accounted by adding their names in the parameter ’brSrcDOL’ in the IBIS Graphical User Interface. As a result of the time delay estimations with the new data, we found that the optical variations are delayed against the X-ray ones by 22.5+0.4 -0.1 s for time interval (Table Presented) (Figure Presented).
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science