[vsnet-grb-info 3312] GRB 060210: Jet Break in the XRT light curve

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5147
SUBJECT: GRB 060210: Jet Break in the XRT light curve
DATE:    06/05/18 00:59:16 GMT
FROM:    Xinyu Dai at Ohio State U  <xinyu at astronomy.ohio-state.edu>

X. Dai and K. Z. Stanek (Ohio State Univ.)

We analyzed the Swift-XRT light curve of GRB 060210 (Beardmore et al. 2006
GCN 4724).  We added new data points to the X-ray light curve presented in 
Stanek et al. 2006 (astro-ph/0602495 v1) up to 1.e6 sec after 
the BAT trigger.  We detected a smooth jet break (t_j = 7.9^{+2.2}_{-1.6}
hr, observed) with the extended XRT light curve.

We fitted both a single power-law and a broken power-law model to the XRT 
light curve from 3.e3 sec to 1.e6 sec after the BAT trigger.  For the 
single power-law model we found alpha=1.09 and chi^2(dof) = 292.3(69). 
For the broken power-law model we found alpha1 = 0.7, alpha2 = 1.4, t_j = 
7.9 hr, and chi^2(dof) = 64.8(67).  We note that the power-law decay index 
for the X-ray light curve before the jet break (alpha1 ~ 0.7) is not 
consistent with the optical index (alpha_o ~ 1.3, Stanek et al. 2006 
astro-ph/0602495).  The XRT light curve for GRB 060210 is at 
http://www.astronomy.ohio-state.edu/~xinyu/grb/060210.jpg

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