GRB 240222A

The Fermi GBM team reports the detection of a likely LONG GRB

At 08:51:31 UT on 22 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240222A (trigger 730284696.466782 / 240222369).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 143.3, Dec = -60.4 (J2000 degrees, equivalent to J2000 09h 33m, -60d 23'), with a statistical uncertainty of 9.1 degrees.

The angle from the Fermi LAT boresight is 109.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240222369/quicklook/glg_skymap_all_bn240222369.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/bn240222369/quicklook/glg_healpix_all_bn240222369.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240222369/quicklook/glg_lc_medres34_bn240222369.gif

P. D'Avanzo (INAF-OAB), R. Brivio (INAF-OAB), S. Dichiara (PSU),
A. Y. Lien (U Tampa), K. L. Page (U Leicester),
C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB) and
B. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 08:51:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240222A (trigger=1216804).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 143.248, -68.029 which is 
   RA(J2000) = 09h 32m 59s
   Dec(J2000) = -68d 01' 43"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 20 sec.  The peak count rate
was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 08:53:05.3 UT, 94.0 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 143.22556, -68.03102 which
is equivalent to:
   RA(J2000)  = 09h 32m 54.13s
   Dec(J2000) = -68d 01' 51.7"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 31 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.72 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 4.6
(+3.44/-2.96) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 98 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.166. 

Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)

R. Brivio, Y.-D. Hu, P. D’Avanzo, M. Ferro, S. Covino, D. Fugazza (INAF-OAB) on behalf of the REM team, report:

We observed the field of GRB 240222A (D'Avanzo et al., GCN 35770
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 ) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, H bands, starting on 2024 February 22 at 08:52:40 UT (i.e. 69 seconds after the burst), and lasting for about 2 hours.

From a preliminary analysis, we find no source at the XRT position down to the following 3sigma magnitude upper limits:

H > 16.7 (Vega; calibrated against the 2MASS catalogue)
at a mid-time of t - t0 = 342 s after the GRB trigger,

r > 18.7  (AB; calibrated against the APASS catalogue)
at a mid-time of t - t0 = 485 s after the GRB trigger.

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-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 240222A ( Fermi GBM team, GCN 35769
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 ) errorbox  33348 sec after notice time and 33382 sec after trigger time at 2024-02-22 18:07:54 UT, with upper limit up to  18.3 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -10.1 deg. 

The galactic latitude b = -6 deg., longitude l = 281 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2383850

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   33473 | 2024-02-22 18:07:54 |         MASTER-SAAO | (09h 40m 49.96s , -68d 03m 28.5s) |   C |   180 | 17.9 |        
   33473 | 2024-02-22 18:07:54 |         MASTER-SAAO | (09h 18m 15.91s , -67d 52m 27.6s) |   C |   180 | 17.4 |        
   33672 | 2024-02-22 18:11:13 |         MASTER-SAAO | (09h 40m 56.74s , -68d 04m 32.3s) |   C |   180 | 18.3 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.

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-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) was pointed to the Swift GRB 240222A ( P. D'Avanzo et al., GCN 35770
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 ) errorbox  33361 sec after notice time and 33382 sec after trigger time at 2024-02-22 18:07:54 UT, with upper limit up to  18.3 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -10.1 deg. 

The galactic latitude b = -12 deg., longitude l = 286 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2383830

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   33473 |         MASTER-SAAO |   C |   180 | 17.9 |        
   33473 |         MASTER-SAAO |   C |   180 | 17.4 |        
   33672 |         MASTER-SAAO |   C |   180 | 18.3 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.

S. R. Oates (Lancaster. U) and P. D'Avanzo (INAF-OAB) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240222A
98s after the BAT trigger (D'Avanzo et al., GCN Circ 35770
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 ). No optical
afterglow consistent with X-ray (D'Avanzo et al., GCN Circ. 35770
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 ) position is
detected in the initial UVOT exposures.

Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white          98            1192          205            >20.9
v              642           1068           58            >18.5
b              567           1168           58            >19.5
u              311           1142          285            >20.0
uvw1           691           1118           39            >18.3
uvm2           666           861            39            >18.0
uvw2           617           1044           58            >18.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.16 in the direction of the burst
(Schlegel et al. 1998).

J. Mangan (CNRS/IJCLab) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 08:51:31.47 UT on 22 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240222A (trigger 730284696/240222369).
which was also detected by Swift BAT (P. D'Avanzo et al. 2024, GCN 35770
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 ).
The Fermi GBM on-ground location is consistent with the Swift BAT position.

The angle from the Fermi LAT boresight is 109 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 3.8 s (50-300 keV). The time-averaged spectrum
from T0-5.9 to T0+3.3 s is best fit by
a simple power law function with index -1.4 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(9.2 +/- 1.9)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.19 s in the 10-1000 keV band is 4 +/- 0.7 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/"

A.P. Beardmore (U. Leicester), R. Brivio (INAF-OAB), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAR), S. Dichiara (PSU), J.A. Kennea
(PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U. Leicester) and P.A.
Evans report on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 240222A, from 106 s to 41.2
ks after the  BAT trigger. The data comprise 9 s in Windowed Timing
(WT) mode (taken while Swift was slewing), with the remainder in Photon
Counting (PC) mode. The refined XRT position is RA, Dec = 143.2254,
-68.0305 which is equivalent to:

RA (J2000): 09 32 54.10
Dec(J2000): -68 01 49.7

with an uncertainty of 3.5 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.02 (+0.12, -0.11).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.52 (+0.24, -0.12). The
best-fitting absorption column is  consistent with the Galactic value
of 1.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 4.6 x 10^-11 (5.3 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.7 (+/-0.9) x 10^21 cm^-2
Galactic foreground: 1.7 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.52 (+0.24, -0.12)

If the light curve continues to decay with a power-law decay index of
2.02, the count rate at T+24 hours will be 1.3 x 10^-5 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.8 x
10^-16 (6.7 x 10^-16) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01216804.

This circular is an official product of the Swift-XRT team.

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
P. D'Avanzo (INAF-OAB), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), T. Sakamoto (AGU)
(i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 240222A (trigger #1216804)
(D'Avanzo et al., GCN Circ. 35770
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 ).  The BAT ground-calculated position is
RA, Dec = 143.209, -68.034 deg which is
   RA(J2000)  =  09h 32m 50.2s
   Dec(J2000) = -68d 02' 03.7"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 94%.

The mask-weighted light curve shows a main pulse that starts
at ~T-0.4 s, peaks at ~T0, and ends at ~T+1.4 s. In addition,
there is a small precursor pulse at ~T-2.7 s. T90 (15-350 keV)
is 3.94 +- 2.35 sec (estimated error including systematics).

The time-averaged spectrum from T-2.70 to T+1.37 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 0.75 +- 0.23.  The fluence in the 15-150 keV band
is 2.5 +- 0.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured
from T-0.20 sec in the 15-150 keV band is 1.3 +- 0.2 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.

The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1216804/

Sheng-Lun Xie, Shao-Lin Xiong, Wen-Long Zhang report on behalf of the GECAM team:

GECAM-B was triggered in-flight and on-ground by a short burst, GRB 240222A, at 2024-02-22T08:51:31.500 UTC (T0), which was also observed by Fermi/GBM (GCN #35769
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  and GCN #35778
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 ) and Swift/BAT (GCN #35770
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  and GCN #35781
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 ). 

According to the GECAM-B light curve, this burst consists of roughly a pulse with a total duration of ~3 sec. 

The GECAM-B ground calculated location (J2000) is:
Ra: 169.76 deg   
Dec: -71.58 deg
Err: 14.01 deg (1-sigma, statistical only)
This GECAM-B localization is consistent with that of Swift/BAT within the error.

We note that these results are very preliminary. Refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).

A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, 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 240222A (Fermi/GBM detection: GCN 35769
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 ; Swift/BAT detection: GCN 35770
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 ; GECAM-B detection: GCN 35782
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 ; INTEGRAL/SPI-ACS peak detection at 2024-02-22 ~08:51:32 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 2024-02-22 08:51:31 UTC. The T90 duration measured by GRBAlpha is 1.5 s and the overall significance during T90 reaches 6.3 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240222A_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. 

J. K. Leung (U. Toronto/HUJI), G. E. Anderson (Curtin University),
S. Chastain (UNM), A. Gulati (U. Sydney), L. Rhodes (U. Oxford),
A. J. van der Horst (GWU) on behalf of the PanRadio GRB collaboration

The Australia Telescope Compact Array (ATCA) performed observations
of GRB 240222A (Fermi GBM Team, GCN 35769
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 ; D'Avanzo et al., GCN 35770
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 )
at 5.5, 9, 16.7 and 21.2 GHz as part of the Large ATCA "PanRadio GRB"
follow-up programme C3542 (PI. Anderson). ATCA observed from
2024-02-24 12:00 UT to 22:00 UT. In our preliminary analysis, we find
no radio source coincident with the refined XRT position (Beardmore
et al., GCN 35780
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 ) with 3 sigma upper limits of 75, 54, 69 and 159
microJy/beam at 5.5, 9.0, 16.7 and 21.2 GHz, respectively.

We thank the CSIRO Space and Astronomy staff for supporting these
observations. We acknowledge the Gomeroi people as the traditional
owners of the Observatory site. The Australia Telescope Compact Array is
part of the Australia Telescope National Facility
(https://ror.org/05qajvd42) which is funded by the Australian Government
for operation as a National Facility managed by CSIRO.