- GCN Circular #37812
SVOM/ECLAIRs Commissioning Team: Jean-Luc Atteia, Laurent Bouchet, Sebastie=
n Guillot, Hui Yang, Juliette Alaux (IRAP), Floriane Cangemi (APC), St=C3=
=A9phane Schanne, Fr=C3=A9d=C3=A9ric Chateau, Nicolas Dagoneau, Herv=C3=A9 =
Le Provost (CEA), Tais Maiolino (LUPM), Wenjin Xie, Donghua Zhao (NAOC), Ka=
rine Mercier, Marie-Claire Charmeau, Stefano Crepaldi (CNES)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), =
Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC), A=
ndrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lacha=
ud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris=
), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV)
Report on behalf of the SVOM team:
During the commissioning phase, the SVOM/ECLAIRs telescope triggered and lo=
cated a bright long burst GRB 241018A (sb24101802) at 2024-10-18T11:54:34 U=
T (T0).
The following trigger information was received on the ground with low-latency
by the SVOM VHF Alert Network.
The burst was detected by both the on-board Count-Rate Trigger (CRT) and Im=
age Trigger (IMT) and 21 alerts were received. The best detection is obtain=
ed by CRT with a signal-to-noise ratio of 107.8 in the 8-120 keV energy ban=
d over a time window of 10.24 s starting at T0.
The burst location is RA, Dec =3D 67.990, 43.030 (J2000).
The statistical uncertainty on this position is 2 arcminutes, to which we r=
ecommend adding 2 arcminutes of systematic uncertainty in quadrature.
SVOM did perform an automatic slew to the burst.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission l=
ed by the Chinese National Space Administration (CNSA), French Space Agency=
(CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to o=
bserving gamma-ray bursts and other transient phenomena in the energetic un=
iverse. ECLAIRs was developed jointly by APC, CEA, CNES, and IRAP.
The SVOM point of contact for this burst is: Jean-Luc.Atteia@irap.omp.eu
- GCN Circular #37814
P. Maggi, L. Michel (ObAS), F. Robinet, N. Leroy (IJCLab), A. Fort, J. Joub=
ert, K. Mercier, S. Crepaldi (CNES), P. Ferrando, D. G=C3=B6tz, A. Meuris, =
M. Moita, C. Plasse, A. Sauvageon (CEA)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), =
Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC), A=
ndrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lacha=
ud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris=
), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shaolin Xiong (IH=
EP), Bing Zhang (UNLV)
Report on behalf of the SVOM team:
MXT started to observe the field of GRB 241018A (Atteia et al., GCN 37812) =
at 11:58:18 UT in an automatic way after ECLAIRs detection and slew of the =
satellite.
The following trigger information was received on the ground using X-band d=
ata
A source is detected at RA=3D 67.9693 Dec =3D 42.997 with a 90% c.l. error=
of 41.7 arcsec before VT bias correction to which we recommend adding 1.5 =
arcminutes of systematic uncertainty in quadrature. The light curve looks f=
lat on 1900 s and the spectrum is hard with photon index =3D 0.85 +/- 0.1, =
at low absorption (NH < 1e20 cm-2). Further results will be given once the =
full telemetry is received and analyzed.
Observations by other telescopes are encouraged.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission l=
ed by the Chinese National Space Administration (CNSA), French Space Agency=
(CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to o=
bserving gamma-ray bursts and other transient phenomena in the energetic un=
iverse. MXT was developed jointly by CEA, CNES, University of Leicester, IJ=
CLab and MPE.
- GCN Circular #37817
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the SVOM/ECLAIRs GRB 241018A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021724
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the SVOM/ECLAIRs event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
- GCN Circular #37818
D. Turpin (CEA/Irfu), J. T. Palmerio (CEA/Irfu, GEPI/Obs. de Paris), A. Sac=
cardi (GEPI/Obs. de Paris, CEA/Irfu), S. Vergani (GEPI/Obs. de Paris), S. B=
asa (UAR Pytheas, OHP, LAM), E. Le Floc'h (CEA Paris-Saclay, DAp/AIM) on be=
half of a larger collaboration.
We observed the field of GRB 241018A detected by SVOM (Atteia et al., GCN 3=
7812) with the LCO 0.4m telescope at the Haleakala Observatory equipped wit=
h the QHY600 CMOS camera . Our observation started at 2024-10-18 12:53:32 (=
T - TGRB ~ 1 h) with 2 series of 5 x 120s in sdss-g and r filter.
We did not detect any uncatalogued optical source in the error region of SV=
OM/ECLAIRs (Atteia et al., GCN 37812) and at the position of the SVOM/MXT a=
fterglow candidate (Maggi et al., GCN 37814). We derived the following uppe=
r limit (5 sigma, AB system) calibrated with the PanSTARRS DR1 catalog and =
not corrected from the significant galactic extinction E(B-V) =3D 0.75:
Tmid-T0 | mag (AB) | filter |
1.07h |19.8 (U.L.) | sdssg |
1.07h |19.6 (U.L.) | sdssr |
This project has received funding from the European Union=E2=80=99s Horizon
2020 research and innovation programme under grant agreement No 101004719.
- GCN Circular #37819
SVOM/VT commissioning team: Y. L. Qiu, C. Wu, L. P. Xin, H. L. Li, X. H. Ha=
n, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. De=
ng, L. Lan, X. M. Lu, R. S. Zhang, (NAOC), J. Zhang, L. J. Dan, G. Y. Zou,=
C. J. Wang, Y. F. Du, C. Huang (XIOPM), H. Zhou (PMO)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), =
Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC), A=
ndrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lacha=
ud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris=
), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV)
report on behalf of the SVOM team:
VT started to observe the field of GRB 241018A triggered by SVOM/Eclairs(At=
teia et al., GCN 37812) in an automatic way after the slew of the satellite=
. The VT conducted observations simultaneously in two channels: VT_B (400nm=
-650nm) and VT_R (650nm-1000nm).
With the VHF data started at 2024-10-18T12:00:28 UT, in which the cataloged=
source brighter than 21 mag is completed relative to the PS1 catalog. An u=
ncatalogued source was found within the errorbox of Eclairs and has an angu=
lar distance of 1.8509 arcmin from the position of MXT (Maggi et al., 37814=
).
The position is RA=04:31:59, DEC=+43:01:12, error=1.0 arcsec, J2000.
The brightness of the source is fading rapidly in 10 min, from 20.9 mag to =
22.2 mag for VT_B and from 18.7 mag to 20.5 mag for VT_R.
We proposed that this source might be the counterpart of the burst. More an=
alysis is continuing with X-band data.
Further follow-ups are encouraged especially in red wavelength.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission l=
ed by the Chinese National Space Administration (CNSA, China), National Cen=
ter for Space Studies (CNES, France) and the Chinese Academy of Sciences (C=
AS, China), which is dedicated to observing gamma-ray bursts and other tran=
sient phenomena in the energetic universe. VT was jointly developed by Xi'a=
n Institute of Optics and Precision Mechanics (XIOPM), CAS and National ast=
ronomical observatories (NAOC),CAS.
- GCN Circular #37821
Daniele B. Malesani (DAWN/NBI and Radboud Univ.), Antonio de Ugarte Postigo (OCA/LAM - CNRS), Ny Avo Rakotondrainibe (LAM), and Alba Casasbuenas Corral, report on behalf of a larger collaboration:
We observed the field of the SVOM GRB 241018A (Atteia et al., GCN 37812; Maggi et al., GCN 37814; Qiu et al., GCN 37814) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. Given the proximity of the bright Moon and the large foreground extinction affecting this field, observations were carried out in the z band filter only, and consisted of 12x200 s exposures, at a mean epoch of 2024 Oct 18.988 UT (10.28 hr after the SVOM trigger).
Following inspection of a preliminary stack of the data, a faint source is marginally detected at a position consistent with the VT optical afterglow candidate (Qiu et al., GCN 37814). We measure a preliminary magnitude z = 22.1 +- 0.3 AB, calibrated against nearby Pan-STARRS objects.
The fading of the source, as well as the association with Swift XRT source #1 (Evans, GCN 37817), further confirm the identification of the VT object as the optical afterglow of GRB 241018A.
We thank the SVOM team, in particular Liping Xin on behalf of VT commissioning team, for providing improved coordinates of the VT source.
- GCN Circular #37822
M. Ferro, P. D=E2=80=99Avanzo, M. G. Bernardini, D. Fugazza, R. Brivio, Y.-=
D. Hu, and S. Covino (INAF-OAB), report on behalf of the REM team:
We observed the field of GRB 241018A detected by SVOM (Atteia et al., GCN 3=
7812; Maggi et al., GCN 37814; Qiu et al., GCN 37819), with the REM 60cm ro=
botic telescope located at the ESO observatory of La Silla (Chile). The obs=
ervations were carried in the g, r, i, z, H bands, starting on 2024 October=
19 at 07:08:55 UT (i.e. 19.2 hours after the Fermi trigger), and lasting f=
or about 40 minutes.
From preliminary photometry at the best candidate afterglow position (Qiu e=
t al., GCN 37819; Malesani et al., GCN 37821) we did not detect any optical=
/NIR counterpart down to the following 3sigma magnitude upper limits:
H > 17.5 (Vega; calibrated against the 2MASS catalogue)
r > 18.9 (AB; calibrated against the PS1 catalogue)
at a mid-time of t - t0 =3D 19.5 hours after the trigger.
- GCN Circular #37823
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), D.N.
Burrows (PSU), M. A. Williams (PSU), S. Dichiara (PSU) and P.A. Evans
(U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the SVOM detected
burst GRB 241018A (GCNs 37812, 37814; Atteia et al., Maggi et al.)
collecting 3.7 ks of Photon Counting (PC) mode data between T0+18.2 ks
and T0+71.2 ks.
Six uncatalogued X-ray sources have been detected in the XRT
field-of-view, of which one (Source 1), is at the location of the
fading optical counterpart seen by the SVOM/VT and NOT (GCNs 37819,
37821; Qiu et al., Malesani et al.), with the following details:
Source 1:
RA (J2000.0): 67.9965 = 04:31:59.15
Dec (J2000.0): +43.0196 = +43:01:10.5
Error: 4.4 arcsec (radius, 90% conf. [Enhanced position])
Count-rate: (8.5 [+2.6, -2.2])e-3 ct s^-1
Distance: 41 arcsec from SVOM/ECLAIRs position.
Flux: (3.27 [+1.00, -0.84])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/00021724.
This circular is an official product of the Swift-XRT team.
- GCN Circular #37824
F.-F. Song (YNAO), X.-H. Han, L.-P. Xin, J. Wang, H.-L. Li, C. Wu (NAOC), R.-Z. Li, B.-T. Wang, J. Mao (YNAO), Y.-L. Qiu, J.-Y. Wei (NAOC), E.-W. Liang, X.-G. Wang (GXU), H. Gao (BNU), J.-J. Jie and J. Zheng (NAOC) report on behalf of a large collaboration:
We observed the field of GRB241018A (Atteia et al., GCN 37812, T0 at 2024-10-18T11:54:34 UT) using the Xinglong-2.16m telescope. The observation began at 2024-10-18T14:50:59, about 2.93 hours after the trigger.
No new uncataloged optical source was detected within the SOVM-ECLAIRs error circle (GCN 37812).
The preliminary analysis results are shown as follows:
+----------------+------------+----------+----------------+
| Tmid-T0 [hr] | Exp. [s] | Filter | 5-sigma U.L. |
+================+============+==========+================+
| 2.97 | 300 | R | 19.09 |
+----------------+------------+----------+----------------+
The given magnitudes are derived based on calibrating against Pan-STARRS1 field stars.
- GCN Circular #37825
T. Mohan, V. Swain, R. Kumar, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of the GRB 241018A (SVOM team, GCN 37812) with the 0.7m GROWTH-India Telescope (GIT). The observations started at 2024-10-18 17:00:48 UT, starting about 5.1 hours after the trigger. We obtained multiple images of 300s each in r', i' and z' filters. We did not detect any new source in our stacked image around the coordinates of the afterglow (SVOM/VT: GCN 37819; Swift XRT: Osborne et al., GCN 37823, Optical NOT: Malesani et al. GCN 37821)
Below is the upper limit in the stacked images:
---------------------------------------------------------------------------------
| MJD (mid) | Filter | Exposure (s) | Limiting Magnitude (AB) |
| ----------------- |------- | ------------------ | -------------- |
| 60601.73736 | r' | 8x300 | 20.2 |
| 60601.84950 | i' | 2x300 | 19.3 |
| 60601.85875 | z' | 1x300 | 18.2 |
---------------------------------------------------------------------------------
Our upper limits are consistent with reports by Turpin et al. (GCN 37818), Ferro et al., (GCN 37822) and Song et al., (GCN 37824).
The GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
- GCN Circular #37826
SVOM/VT commissioning team: Y. L. Qiu, H. L. Li, C. Wu, L. P. Xin, X. H. Ha=
n, J. Wang, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. De=
ng, L. Lan, X. M. Lu, R. S. Zhang, (NAOC), J. Zhang, L. J. Dan, G. Y. Zou,=
C. J. Wang, Y. F. Du, C. Huang (XIOPM), H. Zhou (PMO)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Olivier Godet (IRAP), Arnaud Claret (CEA), =
Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC), A=
ndrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lacha=
ud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris=
), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Bing Zhang (UNLV)
report on behalf of the SVOM team:
With the X-band downlink data, it is confirmed that the counterpart (Qiu et=
al., GCN 37819, Malesani et al., GCN 37821) of GRB 241018A triggered by SV=
OM/Eclairs (Atteia et al., GCN 37812) was clearly detected in VT images in =
both channels. Its brightness had a large fading for about 5 magnitudes wit=
hin our initial observations of 10ks in red band.=20
=20
The improved position is R.A.=3D04:31:59.34, DEC.=3D+43:01:12.3, Error=3D0.=
1 arcsec, J2000, which is fully consistent with the position of Swift XRT
source #1(Osborne et al., GCN 37823).
The Space Variable Objects Monitor (SVOM) is a China-France joint mission l=
ed by the Chinese National Space Administration (CNSA, China), National Cen=
ter for Space Studies (CNES, France) and the Chinese Academy of Sciences (C=
AS, China), which is dedicated to observing gamma-ray bursts and other tran=
sient phenomena in the energetic universe. VT was jointly developed by Xi'a=
n Institute of Optics and Precision Mechanics (XIOPM), CAS and National ast=
ronomical observatories (NAOC),CAS.
- GCN Circular #37827
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin
(IKI) report on behalf of GRB IKI FuN:
We observed the field of GRB 241018A (SVOM team, GCN 37812) with AZT-33IK
telescope of Mondy observatory in R-filter on 2024-10-18 (UT) 15:39:29. The
afterglow (SVOM/VT: GCN 37819; Swift XRT: Osborne et al., GCN 37823,
Optical NOT: Malesani et al. GCN 37821; SVOM/VT commissioning team, GCN
37826) is not detected in a stacked image. Preliminary photometry of the
field is the following.
Date UT start t-T0 Exp. Filter OT Err. UL(3 sigma)
(mid, days) (s)
2024-10-18 15:39:29 0.177032 60x60 R n/d n/d 21.7
The photometry is based on nearby USNO-B1.0 R2 stars.
The result is consistent with previously reported optic non-detection
(Turpin et al., GCN 37818; Ferro et al., GCN 37822; Song et al., GCN 37824;
Mohan et al., GCN 37825)
- GCN Circular #37828
E. Fernandez-Garcia, I. Perez-Garcia, A. J. Castro-Tirado, S.-Y. Wu, M. D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), Y.-D. Hu (INAF-OAB), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga) and D.-R. Xiong, Y.-F. Fan, J.-M. Bai, C.-J. Wang, Y.-X. Xin, X.-H. Zhao (Yunnan Observatories of CAS), on behalf of a larger collaboration, report:
Following the detection of GRB 241018A by SVOM (Atteia et al., GCNC 37812; Maggi et al., GCNC 37814;), we triggered the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical Observatory (China) to follow-up this burst starting on Oct. 18 at 13:12:19 UT (~ 78 min after trigger). The fast decaying afterglow (Qiu et al. GCNC 37819, GCNC 37826) is not detected in the co-added image (15 x 60 s, z filter) down to 19.7 mag, which is consistent with the reports from LCO (Turpin et al. GCNC 37818), NOT (Malesani et al. GCNC 37821), REM (Ferro et al. GCNC 37822), Xinglong (Song et al. GCNC 378), GROWTH (Mohan et al. GCNC 7825) and Mondy (Pankov et al. GCNC 37827).
We thank the staff at Lijiang observatory for their excellent support.
- GCN Circular #37830
Dezi Liu (SWIFAR, YNU), Jinghua Zhang (SWIFAR, YNU), Guowang Du (SWIFAR, YNU), Brajesh Kumar (SWIFAR, YNU), Zhijian Zhang (SWIFAR, YNU), Yule Wang (SWIFAR, YNU), Xinlei Chen (SWIFAR, YNU), Yu Pan (SWIFAR, YNU), Xingzhu Zou (SWIFAR, YNU), Yuanpei Yang (SWIFAR, YNU), Yehao Cheng (SWIFAR, YNU), Yuan Fang (SWIFAR, YNU), Xuhui Han (NAOC), Pinpin Zhang (NAOC), Liping Xin (NAOC), Chao Wu (NAOC), Xiangkun Liu (SWIFAR, YNU), Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team:
The field of SVOM GRB 241018A (Atteia et al., GCN 37812; Maggi et al., GCN 37814) was observed with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Several uvgriz-band images were acquired in moderate sky conditions starting from 20:19:53 2024-10-18 UT (~8.4 hrs after SVOM/Eclairs trigger). At the GRB location, no new candidate (Qiu et al., GCN 37819; GCN 37825; Malesani et al., GCN 37821, Osborne et al., GCN 37823) was detected in the stacked images, consistent with Turpin et al. (GCN 37818), Ferro et al. (GCN 37822), Song et al., (GCN 37824), Mohan et al. (GCN 37825), Pankov et al. (GCN 37827) and Fernandez-Garcia et al. (GCN 37828). The 3-sigma upper limits are the following:
Mid-Time (UT) Band Total-Exp (s) Lim-mag (AB)
2024-10-18T20:33:07 u 180s x 2 >21.07
2024-10-18T20:31:59 v 180s x 2 >21.18
2024-10-18T20:33:04 g 50s x 6 >21.28
2024-10-18T20:31:56 r 50s x 6 >21.53
2024-10-18T20:33:04 i 79s x 4 >20.73
2024-10-18T20:31:56 z 79s x 4 >20.13
--------------------------------------------------------------------------
Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21.
--------------------------------------------------------------------------
- GCN Circular #37831
SVOM/GRM team: Chao Zheng, Chen-Wei Wang, Shi-Jie Zheng, Yong-Wei Dong, Jia=
ng-Tao Liu, Jian-Chao Sun, Yue Huang, Jiang He, Min Gao, Hao-Xuan Guo, Lu L=
i, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming Song, You-Li Tuo,=
Wen-Long Zhang, Wen-Jun Tan, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wa=
ng, 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 (IHEP), Maria-Grazi=
a Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Ta=
is Maiolino (LUPM), Fr=C3=A9d=C3=A9ric Piron (LUPM), St=C3=A9phane Schanne =
(CEA), Jingwei Wang (IAP), JeanLuc Att=C3=A9ia (IRAP)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Fr=
=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP), =
Andrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lac=
haud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Par=
is), 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=
241018A (SVOM trigger reference: sb24101802) at 2024-10-18T11:54:37.500 UT=
(T0), which also triggered SVOM/ECLAIRs (Atteia et al., GCN 37812).
The real-time alert data and light curves of SVOM/GRM were downlinked to th=
e ground through the VHF system with low latency. The light curves show tha=
t this burst consists of multi pulse with a duration (T90) of about 16 s.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb241018A.png
The time-averaged spectrum from T0 to T0+14 s is best fit by a power law fu=
nction with an exponential high-energy cutoff. The power law index is -1.28=
+/- 0.04 and the cutoff energy, parameterized as Epeak, is 117 +/- 5 keV. =
The event fluence (10-1000 keV) in this time interval is (1.11 +/- 0.02)E-0=
5 erg/cm^2.
The Space Variable Objects Monitor (SVOM) is a China-France joint mission l=
ed by the Chinese National Space Administration (CNSA, China), National Cen=
ter for Space Studies (CNES, France) and the Chinese Academy of Sciences (C=
AS, China), which is dedicated to observing gamma-ray bursts and other tran=
sient phenomena in the energetic universe. GRM is developed by the Institut=
e of High Energy Physics (IHEP) of CAS.
The SVOM/GRM point of contact for this burst is: Chao Zheng (IHEP)(zhengcha=
o97@ihep.ac.cn)
- GCN Circular #37832
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 241018A (SVOM detection: Atteia et al., GCN 37812)
triggered Konus-Wind (KW) at T0=3D42881.464 s UT (11:54:41.464).
The burst light curve shows a multi-peaked structure,
which starts at ~T0-3 s, peaks at ~T0+4 s,
and has a total duration of ~12 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/GRB241018_T42881/
As observed by Konus-Wind, the burst had
a fluence of (1.22 =C2=B1 0.18)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 4.224 s,
of (5.34 =C2=B1 0.64)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy =
range).
The time-integrated spectrum (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha =3D -1.12 (-0.21,+0.27),
the high energy photon index beta =3D -2.49 (-0.29,+0.18),
the peak energy Ep =3D 110 (-14,+16) keV,
chi2 =3D 78/86 dof.
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary
- GCN Circular #37836
D. Turpin (CEA), Q. Y. Wu, H. N. Yang, J. W. Hu, H. W. Pan, W. Yuan (NAOC, CAS), C. Plasse, D. Adrien (CEA/irfu), J. Guan, C. K. Li, Y . Chen, S. M. Jia, W. W. Cui, D. W. Han, W. Li, C. Z. Liu, F . J. Lu, L. M. Song, J. Wang, J. J. Xu, J. Zhang, S. N. Zhang, H. S. Zhao, X. F . Zhao (IHEP , CAS), Y . Liu, C. C. Jin, C. Zhang, Z. X. Ling, J. Wang, L. P . Xin (NAOC,CAS), E. Kuulkers, A. Santovincenzo (ESA), P . O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA) on behalf of the SVOM and Einstein Probe teams
We performed a follow-up observation of GRB 241018A (Atteia et al., GCN 37812) with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation started at 2024-10-18T20:47:29.912 (T-TGRB ~ 9hr) for about 3ks of exposure in total.
An uncatalogued X-ray source is detected by both FXT-A and FXT-B at the position (J2000)
RA, DEC = 67.9992, 43.0200 (error=10", 90% C.L.), 43.4 arscecond away from the SVOM/ECLAIRs position (Atteia et al., GCN 37812). This position is also consistent with the optical afterglow detected by SVOM/VT (Qiu et al., GCN 37819, GCN 37826) and the NOT (Malesani et al., GCN 37821) as well as the X-ray counterpart detected by Swift/XRT (Osborne et al., GCN 37823).
A preliminary analysis shows that the spectrum can be fitted with an absorbed powerlaw with nH=9.5(-5.7/+6.9)*10^21 cm^-2 and photon index of 2.5 (-1.1/+1.2) . The observed flux in the 0.5-10.0 keV is 1.8(-0.7/+1.6)*10^-13 erg/s/cm^2.
The above observation was made with the EP-FXT instrument. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). EP is a mission of the Chinese Academy of Sciences in collaboration with ESA, MPE and CNES.
- GCN Circular #37837
Amit K. Ror, Ansika Gupta, Arjun Dawn, Shashi B. Pandey, Kuntal Mishra
(ARIES) report:
We observed the field of GRB 241018A detected by SVOM (SVOM Team, GCN
37812, 37819, 37826), with the 1.3m Devasthal Fast Optical Telescope
(DFOT), located at the Devasthal Observatory of the Aryabhatta Research
Institute of Observational Sciences (ARIES), India. The observations were
started on 2024-10-18 at 17:37:02 UT, i.e., ~ 0.24 days after the SVOM
trigger. We have taken multiple frames with an exposure time of 300 s in
the R filter. The observations were taken in the bright moon phase. We
stacked the images after the alignment. We did not detect any optical
afterglow (SVOM Team, GCN 37819) in our stacked image within the error box
of the improved burst position by SVOM (SVOM Team, GCN 37826). We obtain
the following preliminary 3-sigma upper limit in the stacked image:
Date Start_UT T_start-T0 (days) Filter Exp time (s) Limiting magnitude
=========================================================
2024-10-18 17:37:02 0.24 R 300s*12 > 20.9
Our non-detection is consistent with Turpin et al. 2024, GCN 37818; SVOM
Team, GCN 37819; Malesani et al. 2024, GCN 37821; Ferro et al. 2024, GCN
37822; Song et al. 2024, GCN 37824; Mohan et al. 2024, GCN 37825; Pankov et
al. 2024, GCN 37827; Garcia et al. 2024, GCN 37828; and Liu et al. 2024,
GCN 37830.
The magnitude is not corrected for the Galactic extinction in the direction
of the burst. Photometric calibration is performed using the standard stars
from the USNO-B1.0 catalog. This circular may be cited.
- GCN Circular #37841
SVOM/C-GFT team: Chao WU (NAOC), Zhe Kang (CHO), Liping Xin(NAOC), Xuhui Ha=
n(NAOC), Pinpin Zhang (NAOC), Xiaomeng Lu (NAOC), Zhenwei Li (CHO), You Lv =
(CHO), Ruosong Zhang (NAOC), Yujie Xiao(NAOC)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Fr=
=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC),Olivier Godet (IRAP), =
Andrea Goldwurm (APC), Diego G=C3=B6tz (CEA), Xu-Hui Han (NAOC), Cyril Lach=
aud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Pari=
s), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC), Shao-Lin Xiong (=
IHEP), Bing Zhang (UNLV)
We observed the field of GRB 241018A detected by SVOM (Atteia et al., GCN 3=
7812 and Zheng et al. GCN 37831) on 2024-10-18T11:55:54 UT, 80 seconds afte=
r the trigger with C-GFT in the commissioning phase. A series of g, r and i=
band images were obtained with exposure time of 10s. In our refined proces=
sing, the optical counterpart reported by SVOM/VT (Qiu et al., GCN 37819, G=
CN 37826) and the NOT (Malesani et al., GCN 37821) was detected in our firs=
t sequence of coadded images of band g and r. The results are,
(T-T0)_mid=09mag =09mag_err band
-------------------------------------
118 =09=0917.59 =090.19 =09 g
193=09=0916.90 0.25 r
The photometry was calibrated with nearby PS1 stars.
We thank the observation assistant Guangsheng Zhang and Bowen Li at Jilin o=
bservatory for their excellent support.
Chinese Ground Follow-up Telescope of SVOM mission is located at Jilin, Cha=
ngchun Observatory, National Astronomical Observatories, CAS. It has FOV of
1.28 deg x 1.28 deg with a 4k*4k CMOS detector mounted on the primary focus
of 1.2-meter-aperure telescope.
- GCN Circular #38161
A. Bogomolov, V. Bogomolov, A. Iyudin, S. Svertilov, N. Vasil=E2=80=99ev
on behalf of the MSU =E2=80=9CSozvezdie-270=E2=80=9D team, report:
At 2024-10-18 11:54:37 UT the long-duration GRB 241018A
(SVOM detection: GCN #37812; Konus-Wind detection: GCN #37832)
was detected by the cubesat Avion of the Moscow University project =E2=80=
=9CConstellation-270=E2=80=9D [1].
Total amount of photons detected by Avion in the energy band 40-500 keV is =
234,
it corresponds to a fluence of 1*10^(-6) erg/cm^2.
The LC in the energy band 40-500 keV has two main peaks with maximal flux 7=
.4phot/(cm^2*s)
in the 1st peak and 8.4 phot/(cm^2*s) in the 2nd peak.
Total duration (T90) of the burst is 7 s.
The light curve obtained by Avion is available here:
https://swx.sinp.msu.ru/models/grb_cat/data/pictures/GRB_241018A_Avion_DeCoR1_LC_final_engl_s.png
Parameters of GRB 241018A as well as 20 other GRBs detected by Moscow
University cubesats
are listed at: https://swx.sinp.msu.ru/models/grb_cat/grb.php?lang=3Den
Avion is one of 5 cubesats of the Lomonosov MSU project =E2=80=9CConstellat=
ion-270=E2=80=9D [1]
launched on 2023 June 27. The payload of Avion is a set of scintillation ga=
mma-ray
detectors DeCoR [2], the energy range is >30 keV, the time resolution is=
0.5s.
[1] Svertilov et al. 2023 https://link.springer.com/chapter/10.1007/978-3-031-50248-4_21
[2] Bogomolov et al. 2022 Universe 8, 282 https://www.mdpi.com/2218-1997/8/5/282
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