GCN Circular 11507
Subject
GRB 101225A: MMT spectroscopy
Event
Date
2010-12-29T23:09:32Z (15 years ago)
From
Ryan Chornock at Harvard <rchornock@cfa.harvard.edu>
R. Chornock, G. H. Marion, G. Narayan, E. Berger, and A. M. Soderberg
(Harvard/CfA) report:
We obtained spectroscopy of the optical source (Xu et al., GCN 11495; Xu
et al., GCN 11496; Siegel et al., GCN 11499; Wiersema et al., 11502;
Thoene et al., 11503; Cenko et al., 11506) associated with GRB 101225A
(Racusin et al., GCN 11493) using the Blue Channel Spectrograph on the
6.5-m MMT. Two 2400 s observations starting on December 29.1 UT covered
the spectral range 3175-8385 Angstroms. The source has a smooth blue
continuum and no clear emission or absorption features associated with a
host galaxy are detected in our spectra, similar to the findings of
Wiersema et al. (GCN 11502). In addition, the continuum has no obvious
broad undulations or evidence for line blanketing shortward of 4000
Angstroms, such as would be expected if the spectral features of a
supernova were emerging. The spectrum is well fit by a power law of the
form F_nu ~ constant * nu^(0.4), which is bluer than typical afterglow
spectra, which typically scale as F_nu ~ nu^(-0.6).