Old photographic observations of V4641 Sgr (Goranskij's GM Sgr candidat), the counterpart of X-ray source SAX J1829.3-2525

Taking into account the result by Watanabe P=2.5 days in outburst, I reconstruct old set of photographic observations being partly lost, and add some new observations. A total is of 289 data points. The observations were taken with the Crimean 40-cm astropraph. The periodogram calculated with the method by Lafler and Kinman is shown.

The frequency spectrum calculated using Deeming method shows mach more periodic components.

The last periodogram indicates peaks corresponding following possible periods with the double-wave light curve: 0.4236, 0.4650, 0.5379, 0.6064, 0.7365, 0.871, 1.168, 1.5437, 2.8173, and 6.89 days. One of them, 2.8173 day, is close but non-equal to Watanabe's value. The light curve with this period is shown in the following Figure.

VLA radio interferometric observations of jet in V4641 Sgr