GCN Circular 5271
Subject
GRB 060614: spectroscopy
Date
2006-06-17T21:28:58Z (18 years ago)
From
Daniele Malesani at SISSA-ISAS,Trieste,Italy <malesani@sissa.it>
D. Fugazza (INAF/OABr), M. Della Valle (INAF/OAA), D. Malesani (SISSA),
P. Romano (INAF/OABr), F. Fiore (INAF/OAR), S. Covino (INAF/OABr), G.
Tagliaferri (INAF/OABr), G. Chincarini (Univ. Milano-Bicocca), P.
D'Avanzo (INAF/OABr & Univ. Insubria), S. Piranomonte (INAF/OAR), and L.
Stella (INAF/OAR) report on behalf of the MISTICI collaboration:
We observed the afterglow of GRB 060614 (Parsons et al., GCN 5252;
Mangano et al., GCN 5254; Brown et al., GCN 5262) with the ESO-VLT UT1
and UT2 equipped with FORS2 and FORS1, respectively. Spectra were taken
around Jun 15.416 and Jun 16.313 UT (0.88 and 1.78 days after the burst,
respectively). Despite the bright, closeby Moon, both spectra have a
good signal-to-noise ratio, and cover the wavelenght range 4500-9500 A.
We detect no significant features, neither in absorption nor in
emission. On Jun 15.4, the continuum is well described by a power law
with spectral index beta=0.60 (F_nu propto nu^-beta) in the range
5000-9000 A (where the flux calibration is solid).
The lack of emission features may suggest that the host galaxy is
relatively faint with respect to the afterglow (which had R~20.8 at the
second epoch). For comparison, the spectra of the lowest-redshift GRBs
(e.g. GRB 031203 and GRB 060218) revealed already in the earliest stages
the nebular emission lines from the galaxy. Our observations, therefore,
may imply a redshift larger than ~0.1.
We acknowledge significant support from the VLT staff.
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