[vsnet-grb-info 5230] GRB 071010B: TLS 3rd Epoch - finally a break??

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6923
SUBJECT: GRB 071010B: TLS 3rd Epoch - finally a break??
DATE:    07/10/16 14:53:51 GMT
FROM:    Alexander Kann at TLS Tautenburg  <kann at tls-tautenburg.de>

D. A. Kann, U. Laux & R. Filgas (TLS Tautenburg) report:

We observed the afterglow (Oksanen, GCN 6873) of GRB 071010B (Markwardt et 
al., GCN 6871) with the Tautenburg 1.34m Schmidt telescope under mediocre 
conditions (low transparency), obtaining 12 600 second images in the Rc 
band at 5.3 days after the GRB. The afterglow is faintly detected in all 
frames. We create a stacked image and, using the same comparison stars as 
Kann, Hoegner & Filgas (GCN 6918), we derive the following magnitude:

Date		Mid-Time	Rc	dRc

16.09041	5.22528		21.293	0.045

In comparison with earlier data (see Kann, Hoegner & Filgas, GCN 6918, for 
references, and adding Kocevski et al., GCN 6919; Im, Lee & Urata, GCN 
6920), we find the afterglow to be 0.3 magnitudes fainter than the 
extrapolation of the earlier decay. This may indicate that a break has 
occured.

Inclement weather and an instrument switch will probably not allow us to 
obtain another epoch. Further follow-up at other northern facilities is 
strongly encouraged to check the validity of the break.

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