| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB090228204 |
|
| T0 |
4:53:20.910 UTC |
GCN_circulars,Fermi GBM Det |
| ra |
106.8000° |
Fermi_GBM |
| decl |
-24.3000° |
Fermi_GBM |
| pos_error |
3.79e+00° |
Fermi_GBM |
| T90 |
0.448 s |
Fermi_GBM |
| T90_error |
0.143 s |
Fermi_GBM |
| T90_start |
4:53:20.911 UTC |
Fermi_GBM |
| fluence |
6.19e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
2.65e-08 erg/cm² |
Fermi_GBM |
| T100 |
0.449 s |
|
| GBM_located |
True |
|
| mjd |
54890.20371423611 |
GCN_circulars,Fermi GBM Det |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB090228204 |
| trigger_name |
bn090228204 |
| ra |
106.8000° |
| decl |
-24.3000° |
| pos_error |
3.79e+00° |
| datum |
2009-02-28 |
| t_trigger |
4:53:20.911 UTC |
| T90 |
0.448 s |
| T90_error |
0.143 s |
| T90_start |
4:53:20.911 UTC |
| fluence |
6.19e-06 erg/cm² |
| fluence_error |
2.65e-08 erg/cm² |
| flux_1024 |
1.69e+01 erg/cm²/s |
| flux_1024_error |
3.20e-01 erg/cm²/s |
| flux_1024_time |
-1.28e-01 erg/cm²/s |
| flux_64 |
1.34e+02 erg/cm²/s |
| flux_64_error |
2.74e+00 erg/cm²/s |
| GCN 8918 table |
|---|
| GRB_name |
GRB090228A |
| GCN_number |
8918 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
4:53:20.910 UTC |
| ra |
106.8000° |
| decl |
-24.3000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 8918
SUBJECT: GRB 090228: Fermi GBM detection
DATE: 09/02/28 17:42:15 GMT
FROM: Andreas von Kienlin at MPE
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 04:53:20.91 UT on 28 February 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located the bright short GRB 090228 (trigger 257489602 /
090228204).
The on-ground calculated location, using the GBM trigger
data, is RA = 106.8, DEC = -24.3 (J2000 degrees, equivalent
to 07h 07m, -24d 18'), with a statistical uncertainty of
less than 1 degree (radius, 1-sigma containment) and an additional
systematic error which is currently estimated to be 2 to 3 degrees.
The angle from the Fermi LAT boresight is 16 degrees
This short GRB shows a single bright pulse followed
by a peak of significantly lesser intensity.
The burst duration (T90) is about 0.8 s (8-1000 keV).
The time-averaged spectrum from T0-0.016 s to T0+0.176 s is
best fit by a Band function with Epeak = 849 +/- 44 keV,
alpha = -0.35 +/- 0.04, and beta = -2.98 +/- 0.25
(chi squared 732.29 for 723 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(6.1 +/- 0.09)E-06 erg/cm^2. The 0.32-sec peak photon flux measured
starting from T0 s in the 8-1000 keV band is 133 +/- 8 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
|