| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB250320254 |
|
| T0 |
6:05:44 UTC |
GCN_circulars,Fermi GBM final loc |
| ra |
262.9700° |
Fermi_GBM |
| decl |
47.3400° |
Fermi_GBM |
| pos_error |
2.56e+00° |
Fermi_GBM |
| T90 |
81.409 s |
Fermi_GBM |
| T90_error |
2.36 s |
Fermi_GBM |
| T90_start |
6:05:55.587 UTC |
Fermi_GBM |
| fluence |
6.37e-05 erg/cm² |
Fermi_GBM |
| fluence_error |
1.28e-07 erg/cm² |
Fermi_GBM |
| T100 |
92.996 s |
|
| GBM_located |
True |
|
| mjd |
60754.25398148148 |
GCN_circulars,Fermi GBM final loc |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB250320254 |
| trigger_name |
bn250320254 |
| ra |
262.9700° |
| decl |
47.3400° |
| pos_error |
2.56e+00° |
| datum |
2025-03-20 |
| t_trigger |
6:05:44.579 UTC |
| T90 |
81.409 s |
| T90_error |
2.36 s |
| T90_start |
6:05:55.587 UTC |
| fluence |
6.37e-05 erg/cm² |
| fluence_error |
1.28e-07 erg/cm² |
| flux_1024 |
1.89e+01 erg/cm²/s |
| flux_1024_error |
4.47e-01 erg/cm²/s |
| flux_1024_time |
4.51e+01 erg/cm²/s |
| flux_64 |
2.43e+01 erg/cm²/s |
| flux_64_error |
1.89e+00 erg/cm²/s |
| GCN 39789 table |
|---|
| GRB_name |
GRB250320A |
| GCN_number |
39789 |
| Detection_method |
Fermi GBM final loc |
| t_trigger |
6:05:44 UTC |
| ra |
263.0000° |
| decl |
47.3000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 39789
SUBJECT: GRB 250320A: Fermi GBM Final Real-time Localization
DATE: 25/03/20 06:16:17 GMT
FROM: Fermi GBM Team at MSFC/Fermi-GBM
The Fermi GBM team reports the detection of a likely LONG GRB
At 06:05:44 UT on 20 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250320A (trigger 764143549.57948 / 250320254).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 263.0, Dec = 47.3 (J2000 degrees, equivalent to J2000 17h 32m, 47d 17'), with a statistical uncertainty of 1.2 degrees.
The angle from the Fermi LAT boresight is 105.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250320254/quicklook/glg_skymap_all_bn250320254.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250320254/quicklook/glg_healpix_all_bn250320254.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250320254/quicklook/glg_lc_medres34_bn250320254.gif
|
| GCN 39824 table |
|---|
| GRB_name |
GRB250320A |
| GCN_number |
39824 |
| Detection_method |
Fermi GBM Other |
| ra |
263.0000° |
| decl |
47.3000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 39824
SUBJECT: GRB 250320A: NuSTAR Detection of the Prompt Emission and Preliminary Results
DATE: 25/03/21 21:49:59 GMT
FROM: Brian Grefenstette at Caltech/NuSTAR
B. Grefenstette (Caltech) reports on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group:
The NuSTAR SINGS working group reports the detection of prompt emission from the Long GRB 250320A in both the NuSTAR CsI anti-coincidence shields. This GRB was identified through a blind search using the CsI shield rates. Details of the search algorithm will be described in a future paper.
The NuSTAR SINGS algorithm triggered at 2025-03-20 06:06:19.000 (with a resolution ~5-seconds). This is consistent with the detections by the Fermi GBM (Fermi GBM Team, GCN circ. 39789). The NuSTAR CsI shield data are recorded at 1 Hz. The GRB appears to be composed of a single, broad burst with a duration of over a minute. The peak count rate is roughly 1,500 cps over a baseline rate is ~1,000 cps during this time period. We do not see a clear evidence in the signal above 100 keV in the CdZnTe detectors.
Using the localization from Fermi GBM at RA = 263.0, Dec = 47.3 implies an offset from the NuSTAR boresight of only 17.52 (e.g., through the front of the instrument) and the offset from the geocenter of 103-deg.
Discovery report and preliminary reports for this GRB can be found here:
https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2025/250320A/
Additional analysis will follow.
Information on NuSTAR SINGS can be found here:
https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/
NuSTAR is a NASA Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington.
|