GCN Circular 2123
Subject
GRB 030329, light curve flattens
Date
2003-04-09T17:53:47Z (22 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
A. Henden (USRA/USNO, Flagstaff), B. Canzian (USNO),
A. Zeh, S. Klose (Thueringer Landessternwarte Tautenburg),
on behalf of the FUN and another collaboration
report:
Flagstaff BVRI data reveal that the light curve of the optical
transient (OT) following GRB 030329 has now begun to flatten in all
bands and might be entering the supernova phase. The signal which is
now seen in the light curve shape looks different from all previous
episodes of re-brightening.
The photometric data alone do not yet allow us to state with certainty
what the best fitting parameters of the underlying supernova component
are (see Zeh et al., GCN 2081). The color evolution of the OT until
day 8 after the burst, which was reported in GCN 2115 (Zeh et al.),
seemed to prefer a delay dt between the onset of the supernova and the
onset of the GRB by several days. The inclusion of the Flagstaff data
obtained during the last two nights has changed this picture,
however. Obviously on day 8 the OT underwent another episode of
re-brightening and color change that made it difficult to fit the
observed colors. After exclusion of this effect, a dt close to
0 days is preferred in the color evolution, as well as in the shape of
the R and V-band light curves (-3 < dt <=0). This is in good agreement
with the (stronger) finding based on spectroscopic data (Matheson et
al., GCN 2120).
Figures will be posted at Jochen Greiners internet GRB page.