[vsnet-alert 19367] V404 Cyg outburst

[mkimura]

V404 Cyg outburst

V404 Cyg, an X-ray transient, underwent an outburst this June.
However, it goes an outburst again now !

According to #ATel 8453, MASTER-Amur started observations of
this object at 2015-12-23 09:14:02 UT.  Its unfiltered magnitude is
about 16 mag then.  This magnitude is almost the same as that on
the initial stage of the June outburst (BAAVSS alert 4101) .

V404 Cyg was triggered by the Fermi Gamma Ray Burst Monitor (GBM)
on 2015-Dec-21 at 17:30:50.36 (ATel #8457).  They reported that
the current activity of V404 Cyg was similar to the initial trigger on
2015-June-15.
On 2015-Dec-23 at 05:19:52 UT, the Swift Burst Alert Telescope (BAT)
also triggered it (ATel #8455).
In addition, INTEGRAL IBIS/ISGRI confirmed its renewed activity from
the public observation between 2015-12-21 16:20 and 2015-12-23
04:21 UTC (ATel #8458).

It is well worth observing this outburst of V404 Cyg in optical bands
although we don't know what will happen.
This object is highly reddened, and it would be recommended to
use filters (if possible) and multicolor observations are recommended.

Merry Christmas !  And I hope that it will be a clear night.

Kind regards,
Mariko Kimura



ATel #8453 is following:

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The Astronomer's Telegramhttp://www.astronomerstelegram.org

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ATEL #8453							     ATEL #8453

Title:	 MASTER: optical V404 Cyg microquasar wake up
Author:	V. Lipunov, E. Gorbovskoy, N. Tiurina, V. Kornilov, D. Vlasenko,
		I. Gorbunov, V. Vladimirov  (M. V.Lomonosov Moscow State Univerity,
		SAI), V. Yurkov, Yu. Sergienko, A. Gabovich (Blagoveschensk State
		Pedagogical  University), N. Budnev, O. Gress, K. Ivanov (Applied
		Physics Institute, Irkutsk State University)
Queries:	tiurina at sai.msu.ru
Posted:	23 Dec 2015; 12:33 UT
Subjects:Optical, X-ray, Gamma Ray, Binary, Black Hole, Gamma-Ray
		Burst

MASTER-Amur ( <A HREF="http://www.hindawi.com/journals/aa/2010/349171/">Lipunov
et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 349171</A>
) starts observations of current V404 activity (Swift trigger 668097, S.D.Barthelmy
et al. GCN #18716) at 2015-12-23 09:14:02 UT (V.Yurkov et al., GCN #18717
) just after the sunset .

MASTER-Tunka starts alert observations of V404 at 2015-12-23 10:16:20 UT
(just after the sunset, 17447 sec after notice time and 17787 sec after
trigger time).

There is fast about half-magnitude variability at the interval about 10min
time scale.

Preliminary LC is available athttp://master.sai.msu.ru/static/v404_23dec2015.png

<center><a href="http://observ.pereplet.ru/MASTER_OT.html">List of Optical
Transients discovered by MASTER</a></center>

MASTER Global Robotic Net:http://observ.pereplet.ru
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