[vsnet-alert 8474] Voilent variabilities in V4641 Sgr

[Daisaku NOGAMI]

Dear colleagues,

We have received time-resolve photometric data of V4641 Sgr
obtained by B. Monard, K. Nakajima, H. Maehara in June 24-26.
These data show sudden changes of the state with a timescale
of a few hours, as reported by T. Kato in vsnet-alert 8470.
Such behavior has been also reported in the previous outbursts
(e.g. Uemura et al., 2004, PASJ, 56, 823), but the variability
seems most violent in this outburst!  For example, oscillations
exceeding 0.5 mag with timescales of several minutes.

The more observations, the better, to cover the whole behavior
of this microquasar and to understand the mechanism.  We strongly
encourage all the observers to try to make observations in any
methods (time-resolved and/or multi-color photometry,
time-resolved and/or high-dispersion spectroscopy, polarimetry...)
in nay wave lengths from radio to X-ray.

Best regards,
Daisaku Nogami
On behalf of the VSNET Collaboration Team