| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB090222179 |
|
| T0 |
4:17:07.528 UTC |
Fermi_GBM |
| ra |
118.6000° |
Fermi_GBM |
| decl |
45.0000° |
Fermi_GBM |
| pos_error |
4.34e+00° |
Fermi_GBM |
| T90 |
17.408 s |
Fermi_GBM |
| T90_error |
3.238 s |
Fermi_GBM |
| T90_start |
4:17:07.528 UTC |
Fermi_GBM |
| fluence |
3.23e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
5.38e-08 erg/cm² |
Fermi_GBM |
| T100 |
17.408 s |
|
| GBM_located |
True |
|
| mjd |
54884.17855935185 |
Fermi_GBM |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB090222179 |
| trigger_name |
bn090222179 |
| ra |
118.6000° |
| decl |
45.0000° |
| pos_error |
4.34e+00° |
| datum |
2009-02-22 |
| t_trigger |
4:17:09.576 UTC |
| T90 |
17.408 s |
| T90_error |
3.238 s |
| T90_start |
4:17:07.528 UTC |
| fluence |
3.23e-06 erg/cm² |
| fluence_error |
5.38e-08 erg/cm² |
| flux_1024 |
3.01e+00 erg/cm²/s |
| flux_1024_error |
1.68e-01 erg/cm²/s |
| flux_1024_time |
6.98e+00 erg/cm²/s |
| flux_64 |
4.93e+00 erg/cm²/s |
| flux_64_error |
8.51e-01 erg/cm²/s |
| GCN 8912 table |
|---|
| GRB_name |
GRB090222A |
| GCN_number |
8912 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
4:17:09.580 UTC |
| ra |
120.2000° |
| decl |
43.4000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 8912
SUBJECT: GRB 090222: Fermi GBM detection
DATE: 09/02/22 16:23:16 GMT
FROM: Andreas von Kienlin at MPE
A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:
"At 04:17:09.58 UT on 22 February 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090222 (trigger 256969031 / 090222179).
The on-ground calculated location, using the GBM trigger
data, is RA = 120.2, DEC = +43.4 (J2000 degrees,
equivalent to 08h 01m, +43d 24'), with an uncertainty
of 5.5 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 80 degrees.
The GBM light curve shows one main peak with substructure
with a duration (T90) of about 18 s (8-1000 keV).
The time-averaged spectrum from T0-2.688 s to T0+14.720 s is
well fit by a power law function with an exponential
high energy cutoff. The power law index is -1.00 +/- 0.11
and the cutoff energy, parameterized as Epeak, is 157.7 +/- 19.8 keV
(chi squared 523.89 for 480 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(2.19 +/- 0.19)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+6.528 s in the 8-1000 keV band
is 1.10 +/- 0.14 ph/s/cm^2.
A Band function fits the spectrum equally well
(chi squared 522.58 for 479 d.o.f.) with
Epeak= 147.9 +/- 27.1 keV, alpha = -0.97 +/- 0.14
and beta = -2.56 +/- 0.66.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
|