GRB 220408B
GCN Circular 31854
Subject
GRB 220408B: Fermi GBM Final Localization
Date
2022-04-08T13:59:04Z (3 years ago)
From
Elisabetta Bissaldi at INFN,Bari <elisabetta.bissaldi@ba.infn.it>
The Fermi GBM team reports the detection of a likely LONG GRB.
At 07:28:04.65 UT on 8 Apr 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220408B (trigger 671095689.64512 / 220408311).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 94.8, Dec = -50.9 (J2000 degrees, equivalent to J2000 06h 19m, -50d 54'), with a statistical uncertainty of 2.2 degrees.
The angle from the Fermi LAT boresight is 30.3 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220408311/quicklook/glg_skymap_all_bn220408311.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220408311/quicklook/glg_healpix_all_bn220408311.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220408311/quicklook/glg_lc_medres34_bn220408311.gif
GCN Circular 31858
Subject
Fermi GRB 220408B: Global MASTER-Net observations report
Date
2022-04-08T19:30:22Z (3 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 220408B ( Fermi GBM team, GCN 31854) errorbox 38858 sec after notice time and 38887 sec after trigger time at 2022-04-08 18:16:12 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 33 deg. The sun altitude is -24.1 deg.
The galactic latitude b = -25 deg., longitude l = 259 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1936782
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
38918 | 2022-04-08 18:16:12 | MASTER-SAAO | (06h 12m 56.98s , -50d 05m 58.3s) | C | 60 | 17.8 |
39007 | 2022-04-08 18:17:42 | MASTER-SAAO | (06h 25m 30.38s , -50d 06m 55.8s) | C | 60 | 17.9 |
39088 | 2022-04-08 18:19:03 | MASTER-SAAO | (06h 04m 01.42s , -52d 01m 53.5s) | C | 60 | 17.5 |
39180 | 2022-04-08 18:20:34 | MASTER-SAAO | (06h 16m 56.43s , -52d 00m 18.7s) | C | 60 | 17.4 |
39498 | 2022-04-08 18:25:52 | MASTER-SAAO | (06h 33m 41.72s , -48d 11m 39.6s) | C | 60 | 17.5 |
39589 | 2022-04-08 18:27:23 | MASTER-SAAO | (06h 20m 15.24s , -53d 55m 36.6s) | C | 60 | 17.6 |
39669 | 2022-04-08 18:28:43 | MASTER-SAAO | (06h 33m 53.81s , -53d 55m 10.9s) | C | 60 | 17.6 |
39997 | 2022-04-08 18:34:11 | MASTER-SAAO | (06h 13m 03.64s , -50d 07m 10.9s) | C | 60 | 17.4 |
40088 | 2022-04-08 18:35:42 | MASTER-SAAO | (06h 25m 31.89s , -50d 05m 38.5s) | C | 60 | 17.6 |
40172 | 2022-04-08 18:37:07 | MASTER-SAAO | (06h 03m 58.08s , -52d 00m 16.1s) | C | 60 | 17.5 |
40263 | 2022-04-08 18:38:37 | MASTER-SAAO | (06h 16m 57.23s , -51d 59m 13.9s) | C | 60 | 17.3 |
40354 | 2022-04-08 18:40:09 | MASTER-SAAO | (06h 21m 52.59s , -48d 12m 07.9s) | C | 60 | 17.5 |
40434 | 2022-04-08 18:41:28 | MASTER-SAAO | (06h 33m 43.84s , -48d 13m 07.6s) | C | 60 | 17.5 |
40537 | 2022-04-08 18:43:11 | MASTER-SAAO | (06h 20m 24.77s , -53d 54m 58.6s) | C | 60 | 17.3 |
40669 | 2022-04-08 18:45:23 | MASTER-SAAO | (06h 33m 53.42s , -53d 53m 27.9s) | C | 60 | 17.4 |
40840 | 2022-04-08 18:48:14 | MASTER-SAAO | (06h 11m 00.85s , -48d 11m 45.8s) | C | 60 | 17.5 |
40919 | 2022-04-08 18:49:33 | MASTER-SAAO | (06h 13m 02.11s , -50d 04m 46.1s) | C | 60 | 17.4 |
41011 | 2022-04-08 18:51:05 | MASTER-SAAO | (06h 25m 34.52s , -50d 05m 46.3s) | C | 60 | 17.7 |
41106 | 2022-04-08 18:52:40 | MASTER-SAAO | (06h 04m 01.19s , -52d 00m 39.5s) | C | 60 | 17.1 |
41195 | 2022-04-08 18:54:09 | MASTER-SAAO | (06h 17m 05.09s , -52d 00m 21.5s) | C | 60 | 17.2 |
41291 | 2022-04-08 18:55:45 | MASTER-SAAO | (06h 21m 50.81s , -48d 10m 39.6s) | C | 60 | 17.8 |
41370 | 2022-04-08 18:57:05 | MASTER-SAAO | (06h 33m 49.29s , -48d 12m 25.5s) | C | 60 | 17.3 |
41474 | 2022-04-08 18:58:48 | MASTER-SAAO | (06h 20m 25.74s , -53d 52m 38.1s) | C | 60 | 17.2 |
41565 | 2022-04-08 19:00:19 | MASTER-SAAO | (06h 33m 52.54s , -53d 53m 31.3s) | C | 60 | 17.6 |
41738 | 2022-04-08 19:03:12 | MASTER-SAAO | (06h 36m 42.34s , -50d 06m 22.0s) | C | 60 | 17.6 |
41817 | 2022-04-08 19:04:32 | MASTER-SAAO | (06h 11m 06.65s , -48d 11m 50.7s) | C | 60 | 17.7 |
42081 | 2022-04-08 19:08:55 | MASTER-SAAO | (06h 01m 51.27s , -50d 04m 52.3s) | C | 60 | 17.6 |
42252 | 2022-04-08 19:11:46 | MASTER-SAAO | (06h 08m 09.12s , -53d 53m 57.1s) | C | 60 | 17.7 |
42785 | 2022-04-08 19:20:39 | MASTER-SAAO | (06h 36m 45.22s , -50d 05m 41.5s) | C | 60 | 17.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 31863
Subject
GRB 220408B: AstroSat CZTI detection
Date
2022-04-09T11:38:11Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A.
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat
CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al.,
2021, JApA, 42, 73) showed detection of a long GRB 220408B which was
also detected by Fermi-GBM (GCN 31854).
The source was clearly detected in the 20-200 keV energy range. The
light curve showed multiple peaks of emission with the strongest peak at
2022-04-08 07:28:08.50 UT. The measured peak count rate associated with
the burst is 1181 (+79, -36) counts/s above the background in the
combined data of all four quadrants, with a total of 12408 (+531, -419)
counts. The local mean background count rate was 516 (+2, -4) counts/s.
Using cumulative rates, we measure a T90 of 25 (+3, -1) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve showed multiple peaks
of emission with the strongest peak at 2022-04-08 07:28:08.19 UT. The
measured peak count rate is 1215 (+93, -70) counts/s above the
background in the combined Veto data of four quadrants, with a total of
10873 (+743, -663) counts. The local mean background count rate was 1882
(+4, -5) counts/s. We measure a T90 of 24 (+2, -6) s from the cumulative
Veto light curve.
CZTI GRB detections are reported regularly on the payload site at
http://astrosat.iucaa.in/czti/?q=grb [1]. CZTI is built by a TIFR-led
consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC,
and PRL. The Indian Space Research Organisation funded, managed, and
facilitated the project.
Links:
------
[1] http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 31878
Subject
IPN triangulation of GRB 220408B
Date
2022-04-11T21:15:27Z (3 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo team,
J. Benkhoff on behalf of the BepiColombo team,
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team, report:
The bright, long-duration GRB 220408B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 31854;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 31863)
was detected by Fermi (GBM trigger 671095689), Konus-Wind,
BepiColombo (MGNS), and AstroSat (CZTI) at about 26884 s UT (07:28:04).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
92.538 (06h 10m 09s) -49.610 (-49d 36' 36")
Corners:
93.180 (06h 12m 43s) -49.644 (-49d 38' 40")
93.133 (06h 12m 32s) -47.629 (-47d 37' 43")
91.896 (06h 07m 35s) -49.572 (-49d 34' 20")
91.889 (06h 07m 33s) -51.597 (-51d 35' 50")
---------------------------------------------
The error box area is 1.7 sq. deg, and its maximum
dimension is 4.0 deg (the minimum one is 48 arcmin).
The Sun distance was 86 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of, the
Fermi GBM final position (GCN 31854).
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB220408_T26885/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 31896
Subject
GRB 220408B: Fermi-LAT detection
Date
2022-04-13T15:49:24Z (3 years ago)
From
Elisabetta Bissaldi at INFN,Bari <elisabetta.bissaldi@ba.infn.it>
E. Bissaldi (Politecnico and INFN Bari), M. Arimoto (Kanazawa Univ.),
S. Ciprini (INFN and ASI), F. Giacchino (INFN Roma Tor Vergata and ASI),
M. Giroletti (INAF/IRA Bologna), and L. Scotton (CNRS/IN2P3/LUPM)
report on behalf of the Fermi-LAT team:
"On April 8, 2022, Fermi-LAT detected high-energy emission from GRB 220408B,
which was also detected by Fermi-GBM (trigger 671095689 / 220408311, GCN 31854),
AstroSat CZTI (Gopalakrishnan et al. 2022, GCN 31863) and was reported by the IPN
(Kozyrev et al. 2022. GCN 31878).
The best LAT on-ground location is found to be
RA, Dec = 92.48, -50.97 (degrees, J2000)
with an error radius of 0.06 deg (90 % containment, statistical error only).
This was 30 deg from the LAT boresight at the time of the GBM trigger:
T0 = 07:28:04.65 UT.
The data from the Fermi-LAT show a significant increase in the event rate
that is spatially and temporally correlated with the GBM emission
with high significance.
The photon flux above 100 MeV in the time interval 0-2500s
after the GBM trigger is (2.0 +/- 0.5)E-06 ph/cm2/s.
The estimated photon index above 100 MeV is -1.9 +/- 0.2.
The highest-energy photon is a 22 GeV event
which is observed 42 seconds after the GBM trigger.
The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band
from 20 MeV to greater than 300 GeV. It is the product of an international
collaboration between NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden."
GCN Circular 31905
Subject
Konus-Wind detection of GRB 220408B
Date
2022-04-15T18:11:24Z (3 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
A. Lysenko, D. Frederiks, D. Svinkin, M. Ulanov, A. Tsvetkova,
A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 220408B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 31854;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 31863;
IPN triangulation: Kozyrev et al., GCN Circ. 31878;
Fermi-LAT detection: Bissaldi et al., GCN Circ. 31896;)
triggered Konus-Wind at T0=26885.231 s UT (07:28:05.231).
The burst light curve shows a multipeaked structure
which starts at ~T0-0.5 s and has a total duration of ~35 s.
The emission is seen up to ~3 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220408_T26885/
As observed by Konus-Wind, the burst
had a fluence of 4.1(-0.4,+0.5)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+3.760 s,
of 7.26(-1.60,+1.63)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+30.976 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.80(-0.09,+0.11),
the high energy photon index beta = -2.72(-0.54,+0.29),
the peak energy Ep = 231(-20,+20) keV
(chi2 = 84/81 dof).
The spectrum near the maximum count rate
(measured from T0+0.256 to T0+6.400 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.27(-0.16,+0.18),
the high energy photon index beta = -2.39(-0.21,+0.15),
the peak energy Ep = 211(-20,+23) keV
(chi2 = 80/82 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 31906
Subject
GRB 220408B: Fermi GBM observation
Date
2022-04-15T19:52:40Z (3 years ago)
From
Elisabetta Bissaldi at INFN,Bari <elisabetta.bissaldi@ba.infn.it>
E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 07:28:04.65 UT on 8 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220408B (trigger 671095689 / 220408311),
which was also detected by the AstroSat CZTI (Gopalakrishnan et al. 2022, GCN 31863),
Fermi-LAT (Bissaldi et al. 2022, GCN 31896), and Konus-Wind (Lysenko et al. 2022,
GCN 31905).
The Fermi GBM Final Localization (GCN 31854) is consistent with the LAT position.
The angle from the Fermi LAT boresight at the GBM trigger time is 29 degrees.
The GBM light curve consists of multiple peaks
with a duration (T90) of about 33 s (50-300 keV).
The time-averaged spectrum from T0 to T0+33 s is
best fit by a Band function with Epeak = 214 +/- 8 keV,
alpha = -0.80 +/- 0.02 and beta = -2.33 +/- 0.09.
The event fluence (10-1000 keV) in this time interval is
(3.68 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.6 s in the 10-1000 keV band
is 17.1 +/- 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/"