GRB 240229A
GCN Circular 35833
Subject
GRB 240229A: Fermi GBM Final Real-time Localization
Date
2024-02-29T14:17:34Z (a year ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 14:07:07 UT on 29 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240229A (trigger 730908432.025634 / 240229588).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 199.2, Dec = 16.8 (J2000 degrees, equivalent to J2000 13h 16m, 16d 48'), with a statistical uncertainty of 1.2 degrees.
The angle from the Fermi LAT boresight is 85.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240229588/quicklook/glg_skymap_all_bn240229588.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240229588/quicklook/glg_healpix_all_bn240229588.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240229588/quicklook/glg_lc_medres34_bn240229588.gif
GCN Circular 35834
Subject
GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)
Date
2024-02-29T14:44:04Z (a year ago)
From
Jochen Greiner at MPE <jcgrog@mpe.mpg.de>
Via
email
B. Biltzinger, T. Preis, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
730908432 at 14:07:07 on 29 Feb. 2024 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position is:
RA(2000.0) = 195.9 deg
Decl.(2000.0) = 16.3 deg
The 1 sigma statistical error radius is 1.7 deg.
We estimate an additional systematic error of 1 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB240229588/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB240229588/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB240229588/json
GCN Circular 35838
Subject
Fermi GRB 240229A: Global MASTER-Net observations report
Date
2024-02-29T18:31:22Z (a year ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
legacy email
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(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. Gress, N.M. Budnev, O.Ershova
(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),
V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)
MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 240229A ( Fermi GBM team, GCN 35833) errorbox 565 sec after notice time and 608 sec after trigger time at 2024-02-29 14:17:15 UT, with upper limit up to 17.3 mag. The observations began at zenith distance = 57 deg. The sun altitude is -44.1 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 240229A errorbox 12048 sec after notice time and 12090 sec after trigger time at 2024-02-29 17:28:37 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 80 deg. The sun altitude is -28.0 deg.
The galactic latitude b = 78 deg., longitude l = 336 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2388695
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
668 | 2024-02-29 14:17:15 | MASTER-Amur | (13h 15m 43.59s , +16d 45m 26.5s) | C | 120 | 16.8 |
823 | 2024-02-29 14:19:34 | MASTER-Amur | (13h 15m 45.52s , +16d 46m 56.6s) | C | 150 | 17.1 |
1008 | 2024-02-29 14:22:24 | MASTER-Amur | (13h 15m 40.46s , +16d 45m 49.5s) | C | 180 | 17.1 |
1207 | 2024-02-29 14:25:44 | MASTER-Amur | (13h 15m 39.17s , +16d 46m 37.0s) | C | 180 | 17.1 |
1407 | 2024-02-29 14:29:03 | MASTER-Amur | (13h 15m 45.28s , +16d 45m 24.1s) | C | 180 | 17.1 |
1606 | 2024-02-29 14:32:22 | MASTER-Amur | (13h 15m 39.10s , +16d 44m 09.9s) | C | 180 | 17.0 |
2526 | 2024-02-29 14:48:42 | MASTER-Amur | (13h 18m 12.51s , +18d 16m 37.4s) | C | 60 | 16.4 |
2605 | 2024-02-29 14:50:02 | MASTER-Amur | (13h 26m 32.91s , +18d 16m 02.2s) | C | 60 | 16.6 |
2779 | 2024-02-29 14:52:55 | MASTER-Amur | (13h 10m 35.17s , +18d 15m 01.2s) | C | 60 | 16.6 |
3726 | 2024-02-29 15:08:42 | MASTER-Amur | (13h 18m 05.95s , +18d 14m 13.0s) | C | 60 | 16.9 |
3806 | 2024-02-29 15:10:02 | MASTER-Amur | (13h 26m 39.19s , +18d 14m 47.0s) | C | 60 | 17.2 |
3972 | 2024-02-29 15:12:49 | MASTER-Amur | (13h 10m 34.58s , +18d 13m 28.9s) | C | 60 | 17.3 |
4802 | 2024-02-29 15:26:39 | MASTER-Amur | (13h 18m 12.01s , +18d 14m 50.4s) | C | 60 | 17.1 |
4882 | 2024-02-29 15:27:59 | MASTER-Amur | (13h 26m 31.08s , +18d 14m 32.1s) | C | 60 | 17.1 |
5041 | 2024-02-29 15:30:38 | MASTER-Amur | (13h 10m 36.75s , +18d 13m 13.8s) | C | 60 | 17.2 |
7843 | 2024-02-29 16:17:19 | MASTER-Amur | (13h 10m 09.39s , +16d 15m 21.3s) | C | 60 | 16.6 |
8555 | 2024-02-29 16:29:11 | MASTER-Amur | (13h 18m 24.16s , +16d 15m 56.3s) | C | 60 | 16.4 |
8861 | 2024-02-29 16:34:17 | MASTER-Amur | (13h 10m 09.58s , +16d 15m 00.1s) | C | 60 | 16.5 |
9561 | 2024-02-29 16:45:58 | MASTER-Amur | (13h 18m 31.22s , +16d 15m 28.9s) | C | 60 | 16.5 |
9802 | 2024-02-29 16:49:58 | MASTER-Amur | (13h 10m 05.38s , +16d 12m 45.1s) | C | 60 | 16.5 |
10645 | 2024-02-29 17:04:01 | MASTER-Amur | (13h 18m 25.32s , +16d 12m 21.5s) | C | 60 | 16.4 |
12121 | 2024-02-29 17:28:37 | MASTER-Kislovodsk | (13h 07m 59.15s , +18d 23m 53.3s) | C | 60 | 17.2 |
12915 | 2024-02-29 17:41:52 | MASTER-Kislovodsk | (13h 07m 19.51s , +16d 29m 19.2s) | C | 60 | 17.2 |
12995 | 2024-02-29 17:43:12 | MASTER-Kislovodsk | (13h 15m 39.59s , +16d 30m 02.2s) | C | 60 | 16.9 |
13154 | 2024-02-29 17:45:51 | MASTER-Kislovodsk | (13h 07m 59.06s , +18d 22m 14.0s) | C | 60 | 17.4 |
13551 | 2024-02-29 17:52:28 | MASTER-Kislovodsk | (13h 15m 32.94s , +18d 24m 05.9s) | C | 60 | 16.9 |
13710 | 2024-02-29 17:55:07 | MASTER-Kislovodsk | (13h 23m 59.86s , +18d 21m 58.6s) | C | 60 | 17.1 |
14809 | 2024-02-29 18:12:26 | MASTER-Amur | (13h 22m 10.81s , +14d 44m 23.7s) | R | 180 | 15.4 |
15019 | 2024-02-29 18:15:56 | MASTER-Amur | (13h 20m 47.98s , +15d 00m 15.9s) | R | 180 | 15.0 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 35842
Subject
GRB 240229A: CALET Gamma-Ray Burst Monitor detection
Date
2024-03-01T04:42:26Z (a year ago)
From
Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>
Via
Web form
K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii,
Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 240229 (Fermi GBM Final Real-time Localization:
Fermi GBM team, GCN Circ. 35833; BALROG localization: Biltzinger et al.,
GCN Circ 35834; INTEGRAL SPI ACS: Trigger Num. 10602)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at
14:07:07.40 UTC on 29 February 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1393250567/).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a double-peaked structure that starts
at T+2.9 sec, peaks at T+26.5 sec, and ends at T+36.8 sec.
The T90 and T50 durations measured by the SGM data are 27.6 +/- 2.5 sec
and 19.2 +/- 0.4 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1393250567/index.html
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 35844
Subject
GRB 240229A: DDOTI Upper Limits on the Afterglow
Date
2024-03-02T00:54:46Z (a year ago)
From
Kin O. C. L. Mendoza at Instituto de Astronoma, UNAM <koclopez@astro.unam.mx>
Via
legacy email
Océlotl Lopez (UNAM), Alan M. Watson (UNAM), Rosa L. Becerra (Tor
Vergata Roma),
Margarita Pereyra (UNAM), Nat Butler (ASU), Simone Dichiara (Penn state
university), William H. Lee (UNAM), Alexander Kutyrev (GSFC/UMD),
Tsvetelina Dimitrova (ASU) and Eleonora Troja (Tor Vergata Roma) report:
We observed the field of the Fermi GBM GRB 240229A (Fermi GBM team 2024,
GCN Circ. 35833) with the DDOTI wide-field imager at the Observatorio
Astronómico Nacional on Sierra San Pedro Mártir (
http://ddoti.astroscu.unam.mx) from 2024-03-01 06:10:00 to 12:58:45 UTC
(16.05 to 22.86 hours after the trigger).
We observed a region of 7 degrees in RA by 7 degrees in declination
centered on the Fermi GBM Final Position of RA = 199.18 and Dec = 16.77
(J2000 degrees). This region contains 1 instrumental field or about 49
square degrees. We obtained 103 minutes of exposure per instrumental field
in the w filter. We obtained AB photometry by calibration against the APASS
catalog.
We detect no likely candidates for the afterglow to our 10-sigma upper
limits of w = 19.90 - 20.64 (inter-quartile).
We thank the staff of the Observatorio Astronómico Nacional on San Pedro
Mártir.
GCN Circular 35870
Subject
IPN triangulation of GRB 240229A
Date
2024-03-05T14:06:31Z (a year ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
legacy email
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, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
and
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:
The long-duration GRB 240229A
(Fermi-GBM detection: The Fermi GBM team, GCN 35833;
BALROG localization: Biltzinger et al., GCN 35834;
CALET-CGBM detection: Yamaoka et al., GCN 35842)
was detected by Fermi (GBM trigger 730908432),
INTEGRAL (SPI-ACS), Konus-Wind, CALET (CGBM),
and BepiColombo (MGNS) at about 50827 s UT (14:07:07).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
195.477 (13h 01m 54s) +12.791 (+12d 47' 26")
Corners:
194.744 (12h 58m 59s) +10.021 (+10d 01' 15")
195.408 (13h 01m 38s) +10.063 (+10d 03' 46")
196.123 (13h 04m 30s) +15.555 (+15d 33' 18")
195.453 (13h 01m 49s) +15.513 (+15d 30' 45")
---------------------------------------------
The error box area is 3.5 sq. arcmin, and its maximum
dimension is 5.7 deg (the minimum one is 38.3 arcmin).
The Sun distance was 146 deg.
The IPN localization is consistent with, but reduces the area of,
the final Fermi-GBM and the BALROG localizations.
This localization may be improved.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240229_T50833/IPN
The Konus-Wind time history and spectrum will be given
in a forthcoming GCN circular.
GCN Circular 35872
Subject
GRB 240229A: VZLUSAT-2 detection
Date
2024-03-05T15:04:12Z (a year ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration.
The long-duration GRB 240229A (Fermi/GBM detection: GCN 35833; CALET/CGBM detection: GCN 35842; INTEGRAL/SPI-ACS peak detection at 2024-02-29 ~14:07:35 UT) was detected by the GRB detectors on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).
The data acquisition was performed by the GRB detector units no. 0 and no. 1. The detection was confirmed at the peak time 2024-02-29 14:07:19 (14:06:59) UTC. The T90 duration is 27 s (27 s) and the significance during T90 reaches 16 sigma (11 sigma) for detector unit no. 0 (no. 1).
The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB240229A_GCN_VZLUSAT2.pdf
We note that the light curve measured by VZLUSAT-2 is shifted by approximately 14 s with respect to light curves obtained by other missions. At the moment, the cause of this discrepancy is being investigated.
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/
The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.
GCN Circular 35894
Subject
GRB 240229A: GRBAlpha detection
Date
2024-03-07T12:17:34Z (a year ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa, M. Kolar (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 240229A (Fermi/GBM detection: GCN 35833; CALET/CGBM detection: GCN 35842; VZLUSAT-2 detection: GCN 35872; INTEGRAL/SPI-ACS peak detection at 2024-02-29 ~14:07:35 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).
The detection was confirmed at the peak time 2024-02-29 14:07:33.5 UTC. The T90 duration measured by GRBAlpha is 24.5 s and the overall significance during T90 reaches 9 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240229A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN Circular 35897
Subject
GRB 240229A: Glowbug gamma-ray detection
Date
2024-03-07T14:43:24Z (a year ago)
From
C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>
Via
Web form
C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240229A, which was also detected by Fermi/GBM (GCN 35833, 35834), CALET (GCN 35842), INTEGRAL/SPI-ACS, Konus/Wind, BepiColombo (GCN 35870), VZLUSAT-2 (GCN 35872), and GRBAlpha (GCN 35894).
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-29 14:07:09.552 with a duration of 24.6 s and a total significance of about 27.0 sigma. The light curve comprises two primary peaks at ~T0+3s and ~T0+23s.
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission in two defined intervals from T0 to T0+10.2s and T0+20.5s to +24.6s resulted respectively in photon indices dN/dE~E^x of x=0.5 and x=1.5, and cutoff energies ("Epeak") of 728 keV and 439 keV. The respective modeled 10-10000 keV fluences are 3.9e-06 erg/cm^2 and 9.6e-07 erg/cm^2.
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS. The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
Distribution Statement A: Approved for public release. Distribution is unlimited.
GCN Circular 35903
Subject
GRID detection of GRB 240229A
Date
2024-03-08T16:39:27Z (a year ago)
From
GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>
Via
Web form
Chenyu Wang, Zirui Yang and Longhao Li report on behalf of the GRID Collaboration:
GRID-03B and GRID-04 report the detection of the long-duration GRB 240229A, which was also detected by Fermi/GBM, CALET VZLUSAT-2, GRBAlpha and Glowbug (GCN Circular 35833, 35842, 35872, 35894 and 35897).
The event was triggered with GRID on 2024-02-29 at 14:07:08 UTC and had a double-peak structure. The measured burst duration (T90) in the 30-2000 keV range is approximately 25.0 ± 3.0 seconds.
The time-averaged spectrum of the first peak using GRID-04 realtime data from T+0 to T+10 sec is best fit by a power-law model with a fluence in the 10-1000 keV band is about 3.5259E-05 erg/cm2. The powerlaw index of the time-averaged spectrum is -1.51(-0.06,+0.06). All the quoted errors are at the 1-sigma confidence level.
GCN Circular 35904
Subject
GRID detection of GRB 240229A (Updated Report)
Date
2024-03-08T16:54:57Z (a year ago)
From
GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>
Via
Web form
Chenyu Wang, Zirui Yang and Longhao Li report on behalf of the GRID Collaboration:
GRID-03B and GRID-04 report the detection of the long-duration GRB 240229A, which was also detected by Fermi/GBM, CALET VZLUSAT-2, GRBAlpha and Glowbug (GCN Circular 35833, 35842, 35872, 35894 and 35897).
The event was triggered with GRID on 2024-02-29 at 14:07:08 UTC and had a double-peak structure. The measured burst duration (T90) in the 30-2000 keV range is approximately 25.0 ± 3.0 seconds.
The time-averaged spectrum of the first peak using GRID-04 realtime data from T+0 to T+10 sec is best fit by a power-law model with a fluence in the 10-1000 keV band is about 3.5259E-05 erg/cm2. The powerlaw index of the time-averaged spectrum is -1.51(-0.06,+0.06). All the quoted errors are at the 1-sigma confidence level.
The GRID light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB240229A/GRID_240229A_ltcv.pdf. The GRID spectrum of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB240229A/GRID_240229A_spec_pl.pdf.
GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.