[vsnet-grb-info 19004] GRB 170127C (Fermi/GBM trigger 507173752): AGILE analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20545
SUBJECT: GRB 170127C (Fermi/GBM trigger 507173752): AGILE analysis
DATE:    17/01/27 17:15:24 GMT
FROM:    Francesco Verrecchia at ASDC  <francesco.verrecchia at asdc.asi.it>

AGILE analysis of GRB 170127C (Fermi/GBM trigger 507173752)

A. Ursi (INAF/IAPS), P. Munar-Adrover (INAF/IAPS), F. Verrecchia (ASDC
and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), Y.
Evangelista (INAF/IAPS), F. Lucarelli (ASDC and INAF/OAR), F. Fuschino
(INAF/IASF-Bo), I. Donnarumma (INAF/IAPS), G. Minervini (INAF/IAPS), M.
Marisaldi (INAF/IASF-Bo and Bergen University), A. Bulgarelli, V. Fioretti
(INAF/IASF-Bo), C. Pittori (ASDC and INAF/OAR), G. Piano, A. Argan, E.
Del Monte, L. Pacciani (INAF/IAPS), M. Cardillo (INAF/OA-Arcetri and
INAF/IAPS), A. Giuliani (INAF/IASF-Mi), M. Pilia, A. Trois
(INAF/OA-Cagliari), F. Longo (Univ. Trieste and INFN Trieste), report on
behalf of the AGILE Team:

We performed an analysis of AGILE data of the GRB 170127C (Fermi/GBM
trigger num 507173752; GCN #20543), which occurred at 2017-01-27
01:35:47.79 UTC.

The Mini-CALorimeter (MCAL), sensitive in the energy range from 400 keV
to 100 MeV, detected a short burst at T0 = 2017-01-27 01:35:47.9294 UTC,
that triggered both the on-board 16 ms and 64 ms timescale hardware logic
system. The MCAL light curve shows a sharp single peak, that lasted about
0.13 s and released a total number of ~980 counts above 400 keV in the
detector, above an average background rate of 590 counts/s.

The time-integrated spectrum measured between T0 and T0+0.13 s can be fit
in the energy range 0.5 - 20 MeV with a power law with high-energy
cut-off at 1.63 MeV, with photon index -1.64±0.19 and reduced chi-squared
1.08 (18 d.o.f.). As observed by MCAL, the burst fluence in the same
energy range and time interval is 1.20±0.01e-6 erg cm-2. All quoted
errors are at 90% confidence levels.

SuperAGILE, sensitive in the energy range 18 to 60 keV, also clearly
detected the burst with its ratemeters.