[vsnet-grb-info 3347] GRB 060526: Tautenburg OT observation and light
curve fitting
GCN Circulars
gcncirc at capella.gsfc.nasa.gov
Mon May 29 11:42:39 JST 2006
TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 5182
SUBJECT: GRB 060526: Tautenburg OT observation and light curve fitting
DATE: 06/05/29 02:41:31 GMT
FROM: Alexander Kann at TLS Tautenburg <kann at tls-tautenburg.de>
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D. A. Kann & C. Hoegner (Thueringer Landessternwarte Tautenburg) report:
The afterglow of GRB 060526 (Campana et al., GCN 5162) was observed with the
Tautenburg 1.34m Schmidt telescope in the R band in inclement conditions (passing
clouds). A total of four 600 sec exposures were obtained, each significantly deeper than the
DSS. The afterglow is detected in each image. We measure the magnitude from a stack of
all four images, using the magnitude Khamitov et al. (GCN 5177) derived for the USNO star
at RA=15:31:18.6, Dec=+00:17:34.9 (R=16.848):
Epoch dt (days) Rc dRc
28.9768 2.2904 21.55 0.13
We collect data from Rykoff et al. (GCN 5166), Covino et al. (GCN 5167), Greco et al.
(GCN 5171), Khamitov et al. (GCN 5173), Morgan & Dai (GCN 5175), Khamitov et al. (GCN
5177), Thoene et al. (GCN 5179) and Rumyantsev & Pozanenko (GCN 5181). This data set
can be fit by a single power law with slope alpha = 0.99 +/- 0.01, starting at 6000 seconds
after the burst (Rykoff et al., GCN 5166). But we find significant deviations from the power
law, as high as 0.3 mags above and below (cf. Halpern et al., GCN 5176) the fit, leading to
a high chi^2. This behaviour is reminiscent of GRBs 021004 and 030329. For the data
beyond 1.3 days, we find alpha = 1.64 +/- 0.17, in agreement with Thoene et al. (GCN
5179).
Our data can not rule out that a break in the light curve has occured, lying well on the
extrapolation of the data of Thoene et al. (GCN 5179). If so, the post jet-break decay slope
is very shallow. The afterglow is thus well-suited for further follow-up, and dense R band
imaging is encouraged.
This message may be cited.
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<div align="left"><font face="Arial" size="2"><span style="font-size:10pt">D. A. Kann & C. Hoegner (Thueringer Landessternwarte Tautenburg) report:</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt"><br />
</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt">The afterglow of GRB 060526 (Campana et al., GCN 5162) was observed with the
Tautenburg 1.34m Schmidt telescope in the R band in inclement conditions (passing
clouds). A total of four 600 sec exposures were obtained, each significantly deeper than the
DSS. The afterglow is detected in each image. We measure the magnitude from a stack of
all four images, using the magnitude Khamitov et al. (GCN 5177) derived for the USNO star
at RA=15:31:18.6, Dec=+00:17:34.9 (R=16.848):</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt"><br />
</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt">Epoch               dt (days)           Rc        dRc</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt">28.9768            2.2904              21.55    0.13</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt"><br />
</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt">We collect data from Rykoff et al. (GCN 5166), Covino et al. (GCN 5167), Greco et al.
(GCN 5171), Khamitov et al. (GCN 5173), Morgan & Dai (GCN 5175), Khamitov et al. (GCN
5177), Thoene et al. (GCN 5179) and Rumyantsev & Pozanenko (GCN 5181). This data set
can be fit by a single power law with slope alpha = 0.99 +/- 0.01, starting at 6000 seconds
after the burst (Rykoff et al., GCN 5166). But we find significant deviations from the power
law, as high as 0.3 mags above and below (cf. Halpern et al., GCN 5176) the fit, leading to
a high chi^2. This behaviour is reminiscent of GRBs 021004 and 030329. For the data
beyond 1.3 days, we find alpha = 1.64 +/- 0.17, in agreement with Thoene et al. (GCN
5179).</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt"><br />
</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt">Our data can not rule out that a break in the light curve has occured, lying well on the
extrapolation of the data of Thoene et al. (GCN 5179). If so, the post jet-break decay slope
is very shallow. The afterglow is thus well-suited for further follow-up, and dense R band
imaging is encouraged.</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt"><br />
</span></font></div>
<div align="left"><font face="Arial" size="2"><span style="font-size:10pt">This message may be cited.</span></font></div>
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