| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB181120265 |
|
| T0 |
6:21:19.080 UTC |
GCN_circulars,Fermi GBM Det |
| ra |
20.3792° |
IPN |
| decl |
4.1667° |
IPN |
| pos_error |
1.00e+00° |
IPN |
| T90 |
17.374 s |
Fermi_GBM |
| T90_error |
0.799 s |
Fermi_GBM |
| T90_start |
6:21:19.087 UTC |
Fermi_GBM |
| fluence |
3.55e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
1.66e-08 erg/cm² |
Fermi_GBM |
| T100 |
17.381 s |
|
| GBM_located |
False |
|
| mjd |
58442.26480416667 |
GCN_circulars,Fermi GBM Det |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB181120265 |
| trigger_name |
bn181120265 |
| ra |
20.3800° |
| decl |
4.1700° |
| pos_error |
3.39e+00° |
| datum |
2018-11-20 |
| t_trigger |
6:21:19.084 UTC |
| T90 |
17.374 s |
| T90_error |
0.799 s |
| T90_start |
6:21:19.087 UTC |
| fluence |
3.55e-06 erg/cm² |
| fluence_error |
1.66e-08 erg/cm² |
| flux_1024 |
1.15e+01 erg/cm²/s |
| flux_1024_error |
2.96e-01 erg/cm²/s |
| flux_1024_time |
9.60e-02 erg/cm²/s |
| flux_64 |
1.67e+01 erg/cm²/s |
| flux_64_error |
1.41e+00 erg/cm²/s |
| IPN table |
|---|
| GRB_name |
GRB181120A |
| ra |
20.3792° |
| decl |
4.1667° |
| pos_error |
1.00e+00° |
| GCN 23427 table |
|---|
| GRB_name |
GRB181120A |
| GCN_number |
23427 |
| Detection_method |
Fermi LAT Det |
| t_trigger |
6:21:19.080 UTC |
| ra |
20.3800° |
| decl |
4.1700° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23427
SUBJECT: GRB 181120A: Fermi-LAT detection
DATE: 18/11/20 17:37:37 GMT
FROM: Elisabetta Bissaldi at INFN,Bari
E. Bissaldi (Politecnico & INFN Bari), M. Axelsson (KTH ans Stockholm Univ.),
G. Vianello (Stanford Univ.), F. Longo (Univ. & INFN Trieste), and
D. Kocevski (NASA/MSFC) report on behalf of the Fermi-LAT team:
On November 20, 2018, Fermi-LAT detected high-energy emission from GRB 181120A,
which was also detected by Fermi-GBM (trigger 181120265 / 564387684).
The best LAT on-ground location is found to be
RA, Dec: 20.38, 4.17 (degrees, J2000)
with an error radius of 1 deg (90% containment, statistical error only).
This was 71 deg from the LAT boresight at the time
of the GBM trigger: T0 = 06:21:19.08 UT.
The data from the Fermi-LAT show a significant (~5 sigma) increase
in the event rate in the time interval 3000-6000 s after the
GBM emission. We note that the LAT location is 16 degrees from the GBM one.
Based on our analysis, we rule out contamination from the Earth limb,
and the nearest known point source is ~2 degrees away.
The photon flux above 100 MeV in the time interval 3000-6000 s after the
GBM trigger is (2.2 +/- 0.7)E-06 ph/cm2/s.
The estimated photon index above 100 MeV is 4.0 +/- 0.9.
We note that the spectrum is softer than the one typically seen from GRBs.
The highest-energy photon is a 410 MeV event which is
observed 5530 seconds after the GBM trigger.
A Swift ToO has been requested for this burst.
The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it).
The Fermi-LAT is a pair conversion telescope designed to cover
the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between
NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden.
|
| GCN 23428 table |
|---|
| GRB_name |
GRB181120A |
| GCN_number |
23428 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
6:21:19.080 UTC |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 23428
SUBJECT: GRB 181120A: Fermi GBM observation
DATE: 18/11/20 21:19:58 GMT
FROM: Cori Fletcher at USRA/NASA
C. Fletcher (USRA) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:
"At 06:21:19.08 UT on 20 November 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181120A (trigger 564387684 / 181120265),
which was also detected by the LAT (Bissaldi et al. 2018, GCN 23427)
The GBM on-ground location is consistent with the LAT position.
The angle from the Fermi LAT boresight at the GBM trigger time is 71 degrees.
The GBM light curve shows a single bright pulse followed by extended emission
with a duration (T90) of about 17 s (50-300 keV).
The time-averaged spectrum from T0-0.5 s to T0+16.9 s is best fit by
a power law function with an exponential
high-energy cutoff. The power law index is -0.95 +/- 0.08 and
the cutoff energy, parameterized as Epeak, is 158 +/- 14 keV
The event fluence (10-1000 keV) in this time interval is
(4.60 +/- 0.191)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.1 s in the 10-1000 keV band
is 11.5 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
|