GRB 241016B

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

"At 11:12:40.13 UT on 16 October 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 241016B (trigger 750769965/241016467).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 8.8, Dec = 3.1 (J2000 degrees, equivalent to J2000 00h 35m, +03d 08'),
with a statistical uncertainty of 21 degrees.

The angle from the Fermi LAT boresight is 86 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241016467/quicklook/glg_skymap_all_bn241016467.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/bn241016467/quicklook/glg_healpix_all_bn241016467.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241016467/quicklook/glg_lc_medres34_bn241016467.gif"

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 241016B ( Fermi GBM team, GCN 37797
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 ) errorbox  41136 sec after notice time and 41168 sec after trigger time at 2024-10-16 22:38:48 UT, with upper limit up to  16.6 mag. The observations began at zenith distance = 49 deg. The sun  altitude  is -48.6 deg. 

The galactic latitude b = -59 deg., longitude l = 116 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2640094

We obtain a following upper limits.  

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

   41173 | 2024-10-16 22:38:48 |         MASTER-SAAO | (01h 46m 10.51s , +16d 54m 11.4s) |   C |    10 | 15.7 |        
   41198 | 2024-10-16 22:38:48 |         MASTER-SAAO | (01h 46m 10.50s , +16d 54m 11.5s) |   C |    60 | 16.6 |  Coadd 
   41207 | 2024-10-16 22:39:17 |         MASTER-SAAO | (01h 46m 13.23s , +16d 55m 28.1s) |   C |    20 | 16.0 |        
   41252 | 2024-10-16 22:39:56 |         MASTER-SAAO | (01h 46m 07.22s , +16d 54m 47.9s) |   C |    30 | 16.1 |        
Filter C is a clear (unfiltred) band. 


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

SVOM/GRM team: Wen-Long Zhang, Wen-Jun Tan, Shi-Jie Zheng, Yong-Wei Dong, Jiang-Tao Liu, Jian-Chao Sun, Yue Huang, Jiang He, Min Gao, Hao-Xuan Guo, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming Song, You-Li Tuo, Chen-Wei Wang, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye, Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Yan-Qiu Zhang, Yan-Ting Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng(IHEP), Maria-Grazia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Tais Maiolino (LUPM), Frédéric Piron (LUPM), Stéphane Schanne (CEA), Jingwei Wang (IAP), JeanLuc Attéia (IRAP)

SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP),  Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC),  Shao-Lin Xiong (IHEP), Bing Zhang  (UNLV)

report on behalf of the SVOM team:

During the commissioning phase, the SVOM/GRM was triggered in-flight by GRB 241016B (SVOM trigger reference: sb24101602) at 2024-10-16T11:12:40.100 UT (T0), which was also observed by Fermi/GBM (Fermi GBM team, GCN #37797
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 ).

The real-time alert data and light curves of SVOM/GRM were downlinked to the ground through the VHF system with low latency. The light curves show that this burst consists of single pulse with a duration of about 0.2 s.

The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb241016B.png

The SVOM/GRM on-ground localization of this burst is (J2000):
RA: 38.48 deg
DEC: 27.74 deg
Error: 19.65 deg (1 sigma, statistical only)
We caution that the calibration of SVOM/GRM is undergoing and this localization is subject to systematic errors. The localization may be improved in the refined analysis.

At the time of the burst, ECLAIRs was not collecting data.

The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS.

The SVOM/GRM point of contact for this burst is: Wen-Long Zhang (IHEP)(zhangwl@ihep.ac.cn)

James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: 

Swift/BAT did not localize GRB 241016B onboard (T0: 2024-10-16 11:12:40.13 UTC, Fermi trig 750769965, GCN 37797
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 , SVOM/GRM GCN 37803
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 ) 

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 BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 7.2 in a 0.128 s analysis time bin, starting at T0 - 0.064 s. 

Using the NITRATES analysis, parameter estimation was performed to obtain the localization of this burst in the form of a HEALPIX Multi-Order Coverage (MOC) skymap. This localization accounts for both statistical and systematic errors. More details in the creation and calibration of these maps will soon be published (DeLaunay et al. 2024. in prep)

The 90% credible area is 16,614 deg2 and the 50% credible area is 7,705 deg2.
The integrated probability inside the coded field of view is 2%. 

A plot of the probability skymap can be viewed here,
[https://guano.swift.psu.edu/trigger_report?id=750769994/#:~:text=Probability%20Skymap](https://guano.swift.psu.edu/trigger_report?id=750769994/#:~:text=Probability%20Skymap)

The probability skymap file can be downloaded from the link here,
https://guano.swift.psu.edu/files/750769994/0_n_PROBMAP

Instructions on how to read and manipulate this map can be found here,
https://guano.swift.psu.edu/documentation

More details about this burst can be found on the trigger report page here
https://guano.swift.psu.edu/trigger_report?id=750769994

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/

E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH) 
report on behalf of the Fermi Gamma-ray Burst Monitor Team:


"At 11:12:40.13 UT on 16 October 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 241016B (trigger 750769965/241016467),
which was also detected by SVOM/GRM (Zhang et al. 2024, GCN 37803
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 )
and by Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 37806
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 ).

The angle from the Fermi LAT boresight is 86 degrees.

The GBM light curve consists of two peaks with a duration (T90)
of about 0.8 s (50-300 keV). The time-averaged spectrum
from T0-0.6s to T0+0.7s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is 0.0 +/- 0.5 and the cutoff energy,
parameterized as Epeak, is 840 +/- 380 keV.

The event fluence (10-1000 keV) in this time interval is
(4.1 +/- 0.5)E-07 erg/cm^2. The 64-msec peak photon flux measured
starting from T0-0.064 s in the 10-1000 keV band is 6.4 +/- 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/"