GCN Circular 16171

K. Gazeas & K. Sapountzis (National University of Athens) report:

We performed photometric observations on DG CVn (trigger 596958)
in R band (optical), using the University of Athens Observatory (0.4 m
f/8 Cassegrain Reflector, equipped with a ST10XME CCD camera).

Day/Time of observation: 23/24 April 2014, 22:20-03:00 UT (JD:
2456711.45-2456711.63)
Filters: R (Bessell)

We also conclude that the trigger is consistent with the flare star DG
CVn , although we cannot exclude the possibility of being a field GRB.
Nevertheless, photometry of DG CVn reveals significant enhancing at
the OT and subsequent fading of the flare indicating an interesting
stellar activity. The photometric variability of the DG CVn with
respect to the field standard star GSC 2003:0711, shows a gradual  
decay with a rate of 0.92 mag/hour for the first hour of observation  
after the peak (23:30-00:30 UT), followed by a decay rate of 0.34  
mag/hour for the rest 2.5 hours of observation (00:30-03:00).

The R-band light variability of DG CVn, is shown in the following link:
http://users.uoa.gr/~ksapountzis/DGCVn_UoA_Greece.jpg

[GCN OPS NOTE(25apr14):  This circular was delayed ~5 hours until
and entry in the vetted list was created.]
[GCN OPS NOTE(26apr14):  Per author's request, the last paragraph
(with the lightcurve URL) was added.]
[GCN OPS NOTE(30apr14): Now that it is known that this is about the
Swift-BAT trigger on the DG CVn flare star, the strings "GRB 140423A"
in the Subject-line and in the first paragraph were changed to "DG CVn"
to reflect that.]