GCN Circular 6295
Subject
GRB 070411: TLS data shows plateau, flares
Event
Date
2007-04-13T00:48:22Z (19 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, U. Laux, S. Klose, H. Meusinger, S. Schulze (TLS
Tautenburg) and J. Greiner (MPE, Garching) report:
The afterglow of the Swift GRB 070411 (Moretti et al., GCN
6267) was observed with the Tautenburg 1.34m Schmidt
telescope in RRM mode starting 342 seconds after the trigger
(Kann et al., GCN 6268).
A total of 18 observations were obtained before the afterglow
become unobservable. We performed aperature photometry
vs. two unsaturated and isolated USNO B1.0 stars (R1
magnitudes):
RA = 07:09:17.16, Dec. = +01:04:35.9, assuming R = 15.55
RA = 07:09:28.54, Dec. = +01:03:57.1, assuming R = 16.25
We derive the following magnitudes (mean exposure times
after the burst have been derived logarithmically):
dt Start Exposure R mag dR
(days) (SOD) (seconds)
0.0049994 73095 180 18.03 0.05
0.0076498 73324 180 18.12 0.03
0.0103234 73555 180 18.18 0.03
0.0129739 73784 180 18.17 0.05
0.0156244 74013 180 18.43 0.07
0.0182864 74243 180 18.79 0.05
0.0209485 74473 180 18.83 0.07
0.0235989 74702 180 18.95 0.08
0.0262494 74931 180 19.23 0.07
0.0288999 75160 180 19.38 0.09
0.0315503 75389 180 19.75 0.12
0.0342008 75618 180 20.00 0.16
0.0368512 75847 180 19.83 0.12
0.0395017 76076 180 19.88 0.15
0.0421522 76305 180 20.13 0.19
0.0472965 76540 600 20.64 0.23
0.0548081 77189 600 19.91 0.14
0.0623197 77838 600 19.96 0.15
Adding further R and CR data (Rykoff et al., GCN 6269,
Gomboc et al., GCN 6271, Jelinek, Nuez, & Castro-Tirado,
GCN 6272, Berger et al., GCN 6278, Mikuz, Skvarc, &
Dintinjana, GCN 6288), we find:
The afterglow may be rising early on, looking at the earliest
detections from Crni Vrh, ROTSE and Tautenburg.
The afterglow then goes over into a plateau phase (decay
alpha= 0.14 +/- 0.1). In our data, we do not see the strong
rebrightening detected by ROTSE (Rykoff et al., GCN 6269).
At 0.014 +/- 0.001 days, the afterglow breaks and begins a
decay with alpha = 1.54 +\- 0.16 up to about 0.03 days, where a
possible flare occurs.
At about 0.05 days, the afterglow seems to rebrighten strongly,
our data here are in full accordance with those of the Liverpool
telescope (Gomboc et al., GCN 6271) and the IAC80 (Jelinek,
Nuez, & Castro-Tirado, GCN 6272).
Further photometric follow-up of this GRB is warranted.
This message may be cited.