| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB090820509 |
|
| T0 |
12:13:16.572 UTC |
Fermi_GBM |
| ra |
318.2600° |
Fermi_GBM |
| decl |
-18.5800° |
Fermi_GBM |
| pos_error |
1.13e+01° |
Fermi_GBM |
| T90 |
15.296 s |
Fermi_GBM |
| T90_error |
4.61 s |
Fermi_GBM |
| T90_start |
12:13:16.572 UTC |
Fermi_GBM |
| fluence |
1.34e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
3.81e-08 erg/cm² |
Fermi_GBM |
| T100 |
15.296 s |
|
| GBM_located |
True |
|
| mjd |
55063.509219583335 |
Fermi_GBM |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB090820509 |
| trigger_name |
bn090820509 |
| ra |
318.2600° |
| decl |
-18.5800° |
| pos_error |
1.13e+01° |
| datum |
2009-08-20 |
| t_trigger |
12:13:16.700 UTC |
| T90 |
15.296 s |
| T90_error |
4.61 s |
| T90_start |
12:13:16.572 UTC |
| fluence |
1.34e-06 erg/cm² |
| fluence_error |
3.81e-08 erg/cm² |
| flux_1024 |
5.93e+00 erg/cm²/s |
| flux_1024_error |
2.11e-01 erg/cm²/s |
| flux_1024_time |
9.47e+00 erg/cm²/s |
| flux_64 |
1.02e+01 erg/cm²/s |
| flux_64_error |
8.17e-01 erg/cm²/s |
| GCN 9832 table |
|---|
| GRB_name |
GRB090820B |
| GCN_number |
9832 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
12:13:16.700 UTC |
| ra |
318.3000° |
| decl |
-18.6000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 9832
SUBJECT: GRB 090820B: Fermi GBM detection
DATE: 09/08/21 07:48:55 GMT
FROM: Arne Rau at MPE
Arne Rau (MPE) reports on behalf of the Fermi GBM Team:
"At 12:13:16.70 UT on 20 August 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090820B (trigger 272463198 / 090820509).
The on-ground calculated location, using the GBM trigger
data, is RA = 318.3, DEC = -18.6 (J2000 degrees,
equivalent to 21 h 13 m, -18 d 36 '), with an uncertainty
of 9.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 32 degrees.
The GBM light curve consists of two narrow peaks
with a duration (T90) of about 11.2 s (8-1000 keV).
The time-averaged spectrum from T0-0.128 s to T0+12.160 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -1.44 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 38.8 +/- 4.4 keV
(chi squared 336 for 356 d.o.f.)
The event fluence (8-1000 keV) in this time interval is
(1.16 +/- 0.07)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0-0.128 s in the 8-1000 keV band
is 6.1 +/- 0.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
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