| Summary table |
|---|
| Variable |
Value |
Source |
| GRB_name_Fermi |
GRB230421405 |
|
| T0 |
9:42:41.253 UTC |
Fermi_GBM |
| ra |
41.7042° |
IPN |
| decl |
1.1167° |
IPN |
| pos_error |
8.33e-02° |
IPN |
| T90 |
9.728 s |
Fermi_GBM |
| T90_error |
3.62 s |
Fermi_GBM |
| T90_start |
9:42:41.253 UTC |
Fermi_GBM |
| fluence |
9.76e-07 erg/cm² |
Fermi_GBM |
| fluence_error |
3.57e-08 erg/cm² |
Fermi_GBM |
| T100 |
9.728 s |
|
| GBM_located |
False |
|
| mjd |
60055.404644131944 |
Fermi_GBM |
| Fermi GBM table |
|---|
| GRB_name_Fermi |
GRB230421405 |
| trigger_name |
bn230421405 |
| ra |
44.5500° |
| decl |
5.9600° |
| pos_error |
4.98e+00° |
| datum |
2023-04-21 |
| t_trigger |
9:42:46.373 UTC |
| T90 |
9.728 s |
| T90_error |
3.62 s |
| T90_start |
9:42:41.253 UTC |
| fluence |
9.76e-07 erg/cm² |
| fluence_error |
3.57e-08 erg/cm² |
| flux_1024 |
3.17e+00 erg/cm²/s |
| flux_1024_error |
2.79e-01 erg/cm²/s |
| flux_1024_time |
-2.56e-01 erg/cm²/s |
| flux_64 |
4.99e+00 erg/cm²/s |
| flux_64_error |
1.23e+00 erg/cm²/s |
| IPN table |
|---|
| GRB_name |
GRB230421A |
| ra |
41.7042° |
| decl |
1.1167° |
| pos_error |
8.33e-02° |
| GCN 33668 table |
|---|
| GRB_name |
GRB230421A |
| GCN_number |
33668 |
| Detection_method |
Fermi GBM final loc |
| t_trigger |
9:42:46 UTC |
| ra |
44.5000° |
| decl |
6.0000° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33668
SUBJECT: GRB 230421A: Fermi GBM Final Real-time Localization
DATE: 23/04/21 13:54:39 GMT
FROM: William Cleveland at NASA-MSFC
The Fermi GBM team reports the detection of a likely LONG GRB
At 09:42:46 UT on 21 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230421A (trigger 703762971.373066 / 230421405).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 44.5, Dec = 6.0 (J2000 degrees, equivalent to J2000 02h 58m, 6d 00'), with a statistical uncertainty of 5.5 degrees.
The angle from the Fermi LAT boresight is 99.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230421405/quicklook/glg_skymap_all_bn230421405.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230421405/quicklook/glg_healpix_all_bn230421405.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230421405/quicklook/glg_lc_medres34_bn230421405.gif
|
| GCN 33672 table |
|---|
| GRB_name |
GRB230421A |
| GCN_number |
33672 |
| Detection_method |
Swift Other |
| ra |
41.7040° |
| decl |
1.1190° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33672
SUBJECT: GRB 230421: Swift/BAT-GUANO arcminute localization
DATE: 23/04/21 18:14:17 GMT
FROM: Aaron Tohuvavohu at University of Toronto
James DeLaunay (U Alabama), Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Samuele Ronchini (PSU), Tyler Parsotan (UMBC/GSFC) report:
Swift/BAT did not localize GRB 230431A onboard (T0: 2023-04-21 09:42:46.370000UTC, Fermi/GBM GCN 33668).
The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The burst occured during a Swift slew.
Slew mosaic imaging finds the position of the burst with SNR of 10.5.
The BAT position is
RA, Dec = 41.704, +1.119 deg which is
RA(J2000) = 02h 46m 48.96s
Dec(J2000) = +01d 07′ 08.4″
with an estimated uncertainty of 5 arcmin radius.
The burst location is Sun constrained for Swift, so there will be no XRT or UVOT followup.
GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/
|
| GCN 33675 table |
|---|
| GRB_name |
GRB230421A |
| GCN_number |
33675 |
| Detection_method |
Fermi GBM Det |
| t_trigger |
9:42:46.370 UTC |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33675
SUBJECT: GRB 230421A: Fermi GBM observation
DATE: 23/04/22 18:20:58 GMT
FROM: Oliver J Roberts at USRA/NASA
E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 09:42:46.37 UT on 21 April 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230421A (trigger 703762971 / 230421405),
which was also detected by the Swift/BAT-GUANO (DeLaunay et al. 2023, GCN 33672).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight
at the GBM trigger time is 104 degrees.
The GBM light curve consists of a single emission episode
with a duration (T90) of about 10 s (50-300 keV).
The time-averaged spectrum from T0-1 s to T0+4 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.1 +/- 0.2 and
the cutoff energy, parameterized as Epeak, is 360 +/- 160 keV.
The event fluence (10-1000 keV) in this time interval is
(1.3 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.3 s in the 10-1000 keV band
is 3.2 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" |