| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB250317004 |
|
| T0 |
0:05:22.610 UTC |
Fermi_GBM |
| ra |
148.2400° |
Fermi_GBM |
| decl |
-25.4400° |
Fermi_GBM |
| pos_error |
4.93e+00° |
Fermi_GBM |
| T90 |
17.664 s |
Fermi_GBM |
| T90_error |
2.896 s |
Fermi_GBM |
| T90_start |
0:05:22.610 UTC |
Fermi_GBM |
| fluence |
1.08e-06 erg/cm² |
Fermi_GBM |
| fluence_error |
2.88e-08 erg/cm² |
Fermi_GBM |
| T100 |
17.664 s |
|
| GBM_located |
True |
|
| mjd |
60751.00373391204 |
Fermi_GBM |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB250317004 |
| trigger_name |
bn250317004 |
| ra |
148.2400° |
| decl |
-25.4400° |
| pos_error |
4.93e+00° |
| datum |
2025-03-17 |
| t_trigger |
0:05:29.522 UTC |
| T90 |
17.664 s |
| T90_error |
2.896 s |
| T90_start |
0:05:22.610 UTC |
| fluence |
1.08e-06 erg/cm² |
| fluence_error |
2.88e-08 erg/cm² |
| flux_1024 |
1.89e+00 erg/cm²/s |
| flux_1024_error |
2.37e-01 erg/cm²/s |
| flux_1024_time |
3.84e-01 erg/cm²/s |
| flux_64 |
3.31e+00 erg/cm²/s |
| flux_64_error |
1.14e+00 erg/cm²/s |
| GCN 39748 table |
|---|
| GRB_name |
GRB250317A |
| GCN_number |
39748 |
| Detection_method |
Fermi GBM final loc |
| t_trigger |
0:05:29 UTC |
| ra |
148.2000° |
| decl |
-25.4000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 39748
SUBJECT: GRB 250317A: Fermi GBM Final Real-time Localization
DATE: 25/03/17 00:16:07 GMT
FROM: Fermi GBM Team at MSFC/Fermi-GBM
The Fermi GBM team reports the detection of a likely LONG GRB
At 00:05:29 UT on 17 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250317A (trigger 763862734.52183 / 250317004).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 148.2, Dec = -25.4 (J2000 degrees, equivalent to J2000 09h 52m, -25d 23'), with a statistical uncertainty of 6.3 degrees.
The angle from the Fermi LAT boresight is 23.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250317004/quicklook/glg_skymap_all_bn250317004.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/bn250317004/quicklook/glg_healpix_all_bn250317004.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250317004/quicklook/glg_lc_medres34_bn250317004.gif
|
| GCN 39752 table |
|---|
| GRB_name |
GRB250317A |
| GCN_number |
39752 |
| Detection_method |
Other |
| ra |
211.6650° |
| decl |
40.0560° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 39752
SUBJECT: GRB 250317A: SVOM detection of a burst
DATE: 25/03/17 03:38:10 GMT
FROM: SVOM_group
Donghua Zhao, Yinuo Ma, Wenjin XIE(NAOC), Li Zhang (IHEP), F. Robinet (IJCLab), Liping Xin (NAOC)
on behalf of the SVOM mission team.
At 2025-03-17T02:12:08 UTC (Tb) SVOM/ECLAIRs triggered on the gamma-ray burst GRB 250317A (SVOM burst-id sb25031701). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.
The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 13 alerts. CRT provided the alert with the best signal-to-noise-ratio (SNR) of 14.27 in the [5-8] keV energy band over a time window of 40.96 seconds starting at Tb.
The light curve showed a broad peak structure with a T90 duration of about 145.67 (-0.16 +0.16).
The localization of the best alert is R.A., Dec 211.665, 40.056 degrees (J2000) with a 90% C.L. radius of 5.75 arcmin (including systematic error of 2 arcmin added in quadrature).
SVOM slewed to the burst.
MXT began observing the field at 2025-03-17T02:14:36 UTC, 148 seconds after Tb. Using onboard processed data we found a bright and rapidly fainting uncatalogued X-ray source located at R.A., Dec 211.648, 40.057 degrees:
RA (J2000) = 14h06m35s
DEC (J2000) = 40d03m23s
with a 90% C.L. radius of 25 arcseconds.
This location is 48 arcseconds away from the ECLAIRs onboard position.
VT began to observe the field after the slew. No uncatalogued sources were detected within MXT errors compared to DESI catalog based on the VHF sequences. The 3 sigma limit magnitude is about VT_R~21 mag (AB) at about 10 minutes after the trigger. More analysis will be performed after receiving the X band data later.
The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe.
The Burst Advocate (BA) on shift for this burst is Donghua Zhao (zhaodh@bao.ac.cn).
Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst.
|