Swift triggers on V404 Cyg
ATel #8455; A. P. Beardmore (U. Leicester), K. L. Page (U. Leicester), E. Kuulkers (ESAC/ESA)
on 23 Dec 2015; 17:00 UT
On 2015-Dec-23 at 05:19:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source consistent with V404 Cyg (trigger=668097; GCN Circ. 18716). As is typical with BAT image triggers, the real-time light curve did not show anything significant. However, this is the first automatic detection of V404 Cyg by BAT since the on-board trigger threshold level was reset back to the pre-2015 June outburst value for the source on 2015-Aug-03.
...
The Swift UV and Optical Telescope (UVOT) obtained white and v-band images of the field which showed the source at magnitudes of 17.79+/-0.06 and 16.23+/-0.25, respectively. The latter is consistent with the MASTER-Tunka observations taken 3.5 hours later (GCN Circ. 18718).
Further Swift observations have been approved in an attempt to determine whether the source is entering another active phase.
Complete text: http://www.astronomerstelegram.org/?read=8455
Merry Christmas and clear skies!
Patrick
Thanks for posting this, Patrick. The source seems to be borderline active, but there is something in x-rays that makes it suspicious. I would like to encourage optical observations; it would be very interesting (and rare!) for this object to go through a second flaring phase in a year!
During the June optical flare, we issued the following alert, which has more information on the source and can assist with new observations:
https://www.aavso.org/aavso-alert-notice-520
Sequences for the star and finding charts can be created through VSP. Let's see what the object is doing this time...
Best wishes - clear skies,
Stella.
I would like to encourage anyone who can observe this target to acquire data and send them to the AAVSO. It seems that V404 Cyg is doing something "interesting" in x-rays!
Best wishes - clear skies,
Stella.
V0404 Cyg brightened to around mag 12.5 in the I band as of JD2457388.26100
Douglas
Optical spectra by Peter Somogyi (HAA/VSS) of the recent rebrightening:
http://www.spectro-aras.com/forum/download/file.php?id=2790
Animamation:
http://www.spectro-aras.com/forum/download/file.php?id=2791
More details:
http://www.spectro-aras.com/forum/viewtopic.php?f=5&t=1167
Observations by Tamás Tordai (HAA/VSS) show it peaked around 13.7V in the evening 31 December:
https://dl.dropboxusercontent.com/u/6019817/V404_Cyg--JD57388.png
Clear skies,
Robert
Lots of activity in the optical and in x-rays:
http://www.astronomerstelegram.org/?read=8500
Cygnus is getting low in the horizon, but more observations are strongly encouraged for as long as possible!
Best wishes - clear skies,
Stella.