[vsnet-campaign-xray 10] V4641 Sgr increased activity?

[Taichi Kato <tkato>]

V4641 Sgr increased activity?

   We have just received a news that the peculiar X-ray transient known as
V4641 Sgr = XTE J1819-254 may have started its activity.  The dramatic
outburst of this "hidden" black hole binary is still fresh in our minds,
whose giant optical outburst ocurred in 1999 September, independently
discovered by Rod Stubbings and the Kyoto University team.  The discovery
of the burst was soon relayed to X-ray and radio observers, who conducted
ToO (Target-of-Opportunity) observations to reveal a rapidly growing short
intesive X-ray flare (the object reached the second brightest X-ray source
except the Sun!) associated with relativistic jet ejection.  The discovery
story of the giant optical flash of V4641 Sgr (called as GM Sgr at that
time) can be seen at:

   http://www.kusastro.kyoto-u.ac.jp/vsnet/Xray/gmsgr.html

   Please watch the activity of this star closely, and report to us when
you catch apparent activities!  Detailed reports may also appear in
vsnet-campaign-xray.

Regards,
Taichi Kato
VSNET Collaboration team

VSNET Home Page

---

vsnet-adm@kusastro.kyoto-u.ac.jp

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp