- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Tue 10 Sep 24 04:01:14 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 48
TRIGGER_NUM: 747633649
GRB_RA: 10.850d {+00h 43m 24s} (J2000),
11.172d {+00h 44m 41s} (current),
10.200d {+00h 40m 48s} (1950)
GRB_DEC: +11.033d {+11d 01' 60"} (J2000),
+11.168d {+11d 10' 06"} (current),
+10.760d {+10d 45' 34"} (1950)
GRB_ERROR: 25.38 [deg radius, statistical plus systematic]
GRB_INTEN: 122 [cnts/sec]
DATA_SIGNIF: 5.80 [sigma]
INTEG_TIME: 1.024 [sec]
GRB_DATE: 20563 TJD; 254 DOY; 24/09/10
GRB_TIME: 14444.21 SOD {04:00:44.21} UT
GRB_PHI: 198.00 [deg]
GRB_THETA: 95.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO: 1.25
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 97% GRB
2nd_MOST_LIKELY: 1% Generic SGR
DETECTORS: 0,0,0, 0,0,0, 0,0,1, 0,0,1, 0,0,
SUN_POSTN: 168.91d {+11h 15m 39s} +4.76d {+04d 45' 50"}
SUN_DIST: 152.72 [deg] Sun_angle= 10.5 [hr] (West of Sun)
MOON_POSTN: 242.58d {+16h 10m 20s} -25.71d {-25d 42' 24"}
MOON_DIST: 129.45 [deg]
MOON_ILLUM: 39 [%]
GAL_COORDS: 119.74,-51.79 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 14.30, 5.86 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240910167/quicklook/glg_lc_medres34_bn240910167.gif
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 62.60,20.82 [deg].
COMMENTS: The LC_URL file will not be created until ~15 min after the trigger.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Tue 10 Sep 24 04:01:24 UT
NOTICE_TYPE: Fermi-GBM Flight Position
RECORD_NUM: 59
TRIGGER_NUM: 747633649
GRB_RA: 15.683d {+01h 02m 44s} (J2000),
16.006d {+01h 04m 01s} (current),
15.030d {+01h 00m 07s} (1950)
GRB_DEC: +9.650d {+09d 39' 00"} (J2000),
+9.782d {+09d 46' 56"} (current),
+9.382d {+09d 22' 54"} (1950)
GRB_ERROR: 9.35 [deg radius, statistical plus systematic]
GRB_INTEN: 155 [cnts/sec]
DATA_SIGNIF: 15.90 [sigma]
INTEG_TIME: 4.096 [sec]
GRB_DATE: 20563 TJD; 254 DOY; 24/09/10
GRB_TIME: 14444.21 SOD {04:00:44.21} UT
GRB_PHI: 203.00 [deg]
GRB_THETA: 95.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO: 1.04
LOC_ALGORITHM: 3 (version number of)
MOST_LIKELY: 97% GRB
2nd_MOST_LIKELY: 1% Generic SGR
DETECTORS: 0,0,0, 0,0,0, 0,0,1, 0,0,1, 0,0,
SUN_POSTN: 168.91d {+11h 15m 39s} +4.76d {+04d 45' 50"}
SUN_DIST: 149.34 [deg] Sun_angle= 10.2 [hr] (West of Sun)
MOON_POSTN: 242.59d {+16h 10m 20s} -25.71d {-25d 42' 25"}
MOON_DIST: 133.16 [deg]
MOON_ILLUM: 39 [%]
GAL_COORDS: 127.57,-53.12 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 18.15, 2.74 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240910167/quicklook/glg_lc_medres34_bn240910167.gif
COMMENTS: Fermi-GBM Flight-calculated Coordinates.
COMMENTS: This trigger occurred at longitude,latitude = 62.60,20.82 [deg].
COMMENTS: The LC_URL file will not be created until ~15 min after the trigger.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Tue 10 Sep 24 04:01:32 UT
NOTICE_TYPE: Fermi-GBM Ground Position
RECORD_NUM: 58
TRIGGER_NUM: 747633649
GRB_RA: 15.380d {+01h 01m 31s} (J2000),
15.702d {+01h 02m 48s} (current),
14.729d {+00h 58m 55s} (1950)
GRB_DEC: +8.700d {+08d 41' 60"} (J2000),
+8.832d {+08d 49' 57"} (current),
+8.431d {+08d 25' 52"} (1950)
GRB_ERROR: 4.18 [deg radius, statistical only]
DATA_SIGNIF: 18.30 [sigma]
DATA_INTERVAL: 4.096 [sec]
GRB_DATE: 20563 TJD; 254 DOY; 24/09/10
GRB_TIME: 14444.21 SOD {04:00:44.21} UT
GRB_PHI: 203.00 [deg]
GRB_THETA: 96.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 4173 (Gnd S/W Version number)
SUN_POSTN: 168.91d {+11h 15m 39s} +4.76d {+04d 45' 50"}
SUN_DIST: 150.03 [deg] Sun_angle= 10.2 [hr] (West of Sun)
MOON_POSTN: 242.59d {+16h 10m 21s} -25.71d {-25d 42' 26"}
MOON_DIST: 132.46 [deg]
MOON_ILLUM: 39 [%]
GAL_COORDS: 127.18,-54.09 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 17.51, 1.98 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240910167/quicklook/glg_lc_medres34_bn240910167.gif
POS_MAP_URL: http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_747633649.fits
COMMENTS: Fermi-GBM Ground-calculated Coordinates.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: The LC_URL file will not be created/available until ~15 min after the trigger.
COMMENTS: The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.
- GCN NOTICE
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Tue 10 Sep 24 04:10:02 UT
NOTICE_TYPE: Fermi-GBM Final Position
RECORD_NUM: 0
TRIGGER_NUM: 747633649
GRB_RA: 15.050d {+01h 00m 12s} (J2000),
15.369d {+01h 01m 29s} (current),
14.404d {+00h 57m 37s} (1950)
GRB_DEC: +4.500d {+04d 30' 00"} (J2000),
+4.633d {+04d 37' 58"} (current),
+4.231d {+04d 13' 51"} (1950)
GRB_ERROR: 4.50 [deg radius, statistical only]
GRB_DATE: 20563 TJD; 254 DOY; 24/09/10
GRB_TIME: 14444.21 SOD {04:00:44.21} UT
GRB_PHI: 204.00 [deg]
GRB_THETA: 100.00 [deg]
E_RANGE: 44.032 - 279.965 [keV]
LOC_ALGORITHM: 41731 (Gnd S/W Version number)
SUN_POSTN: 168.92d {+11h 15m 41s} +4.76d {+04d 45' 42"}
SUN_DIST: 151.96 [deg] Sun_angle= 10.2 [hr] (West of Sun)
MOON_POSTN: 242.66d {+16h 10m 40s} -25.72d {-25d 43' 26"}
MOON_DIST: 130.10 [deg]
MOON_ILLUM: 39 [%]
GAL_COORDS: 127.09,-58.30 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 15.60, -1.78 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240910167/quicklook/glg_lc_medres34_bn240910167.gif
LOC_URL: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240910167/quicklook/glg_locplot_all_bn240910167.png
COMMENTS: Fermi-GBM Final Position.
COMMENTS: This Notice was ground-generated -- not flight-generated.
COMMENTS: The LC_URL file should be available by the time this FINAL notice is produced.
COMMENTS: This notice was generated completely by automated pipeline processing.
COMMENTS: This is likely a Long GRB.
- GCN Circular #37441
The Fermi GBM team reports the detection of a likely LONG GRB
At 04:00:44 UT on 10 Sep 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240910A (trigger 747633649.214168 / 240910167).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 15.1, Dec = 4.5 (J2000 degrees, equivalent to J2000 01h 00m, 4d 30'), with a statistical uncertainty of 4.5 degrees.
The angle from the Fermi LAT boresight is 100.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240910167/quicklook/glg_skymap_all_bn240910167.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/bn240910167/quicklook/glg_healpix_all_bn240910167.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240910167/quicklook/glg_lc_medres34_bn240910167.gif
- GCN Circular #37442
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 240910A ( Fermi GBM team, GCN 37441) errorbox 89 sec after notice time and 126 sec after trigger time at 2024-09-10 04:02:51 UT, with upper limit up to 12.5 mag. Observations started at twilight. The observations began at zenith distance = 66 deg. The sun altitude is -9.5 deg.
The galactic latitude b = -58 deg., longitude l = 128 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2596454
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
137 | 2024-09-10 04:02:51 | MASTER-SAAO | (01h 00m 48.59s , +08d 27m 33.5s) | C | 20 | 12.5 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
- GCN Circular #37445
SVOM/GRM team: Wen-Long Zhang, Wen-Jun Tan, Yong-Wei Dong, Jiang-Tao Liu, S=
hi-Jie Zheng, Jian-Chao Sun, Yue Huang, Jiang He, Chen-Wei Wang, Min Gao, H=
ao-Xuan Guo, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming =
Song, You-Li Tuo, 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-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 (L=
UPM), Fr=C3=A9d=C3=A9ric Piron (LUPM), St=C3=A9phane Schanne (CEA), Jingwei=
Wang (IAP)
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), JeanLuc Att=C3=A9ia (IRAP), Arnaud Claret (=
CEA), Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NA=
OC), Andrea Goldwurm (APC), Diego G=C3=B6tz (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), Bing Zhang (=
UNLV)
report on behalf of the SVOM team:
During the commissioning phase, the SVOM/GRM was triggered in-flight by GRB=
240910A (SVOM trigger reference: sb24091005) at 2024-09-10T04:00:46.000 UT=
(T0), which was also observed by Fermi/GBM (GCN 37441).
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 multiple pulses in 300 s.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb240910A.png
The Fermi localisation of this burst was not in the ECLAIRs field of view.
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: Wen-Long Zhang (IHEP)(zhan=
gwl@ihep.ac.cn)
- GCN Circular #37450
J. Ripa, M. Dafcikova, 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, M. Dur=
iskova, 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. Ha=
nak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Cen=
ter/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (IS=
AS/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 (Hirosh=
ima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos=
U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakaz=
awa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torig=
oe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Morit=
aki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 240910A (Fermi/GBM detection: GCN 37441; SVOM/GRM det=
ection: GCN 37445) 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/abs=
tract).
The detection was confirmed at the peak time 2024-09-10 04:02:51.9 UTC. The=
T90 duration measured by GRBAlpha is 107 s and the overall significance du=
ring T90 reaches 7.4 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.ko=
nkoly.hu/static/share/GRB240910A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/he=
a/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a futur=
e CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GR=
BAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM ar=
ray, covering the energy range from ~50 keV to ~1000 keV. To increase the d=
uty cycle and the downlink rate, the upgrade of the on-board data acquisiti=
on software stack is in progress. The ground segment is also supported by t=
he radio amateur community and it takes advantage of the SatNOGS network fo=
r increased data downlink volume.
- GCN Circular #37456
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/GBM GRB 240910A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021712
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 Fermi/GBM 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 #37459
Y. Julakanti, A. Kumar, D. O=E2=80=99Neill, B. P. Gompertz, M. Kennedy, B. =
Godson, K. Wiersema, R. Starling, K. Ackley; M. J. Dyer; J. Lyman; K. Ulacz=
yk; F. Jimenez-Ibarra; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; =
G. Ramsay; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Palle and =
D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Obs=
erver (GOTO; Steeghs et al. 2022) in response to Fermi/GBM GRB 240910A (tri=
gger 747633649.214168/240910167; Fermi GBM Team, GCN 37441; Zhang et al. GC=
N 37445; Ripa et al. GCN 37450). Targeted observations were performed by GO=
TO South from 2024-09-10 13:26:31 UT to 2024-09-11 02:36:55 UT (respectivel=
y from +9.42 to +22.60 hours post trigger). Each observation consisted of 4=
x90s exposures in the GOTO L-band (400-700 nm).
In total, 283.9 square degrees within the 90% contour were imaged, resultin=
g in a coverage total of ~89.1% of the total 2D localisation probability. 2=
24 images were taken across 13 unique pointings, with an average 5-sigma de=
pth of 19.9 mag.
Images were processed immediately after acquisition using the GOTO pipeline.
Difference imaging was performed using recent survey observations of the
same pointings. Source candidates were initially filtered using a classifie=
r (Killestein et al. 2021) and cross-matched against a variety of contextua=
l and minor planet catalogs. Human vetting was carried out in real time on
any candidates that passed the above checks.
A new optical source GOTO24fvl/AT2024vfp (https://www.wis-tns.org/object/20=
24vfp) is identified within the GBM 90% localisation region at J2000 coordi=
nates RA =3D 01:36:23.45; Dec =3D -00:12:17.86. The source was initially de=
tected at L-band magnitude of 19.23 +/- 0.12, 9.43 hours post trigger, with=
further detections at 19.65 +/- 0.12 mag (10.56 hours) and 19.63 +/- 0.14
mag, 12.01 hours post trigger, consistent with a decay rate t^(-1.56 +/- 1.=
20). The source was not detected down to a 5-sigma depth of L =3D 19.41 mag=
, 3.09 days prior to the GRB trigger.
We find no evidence of this source prior to the GRB trigger time in previou=
s GOTO observations, the ZTF observations provided by the Lasair broker (Sm=
ith et al. 2019), or the ATLAS forced photometry server (Shingles et al. 2021).
The rate of evolution, coupled with the spatial and temporal coincidence of
GOTO24fvl/AT2024vfp with GRB 240910A, make it a plausible afterglow candid=
ate, but we caution we cannot confidently associate the two sources based o=
n the available observations. A Swift ToO to search for associated X-ray em=
ission has been requested (Evans et al., GCN 37456).
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are
not corrected for Galactic extinction. Further observations are planned.
GOTO (https://goto-observatory.org) is a network of telescopes that is prin=
cipally funded by the STFC and operated at the Roque de los Muchachos Obser=
vatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia,
on behalf of a consortium including the University of Warwick, Monash Univ=
ersity, Armagh Observatory & Planetarium, the University of Leicester, the
University of Sheffield, the National Astronomical Research Institute of Th=
ailand (NARIT), the University of Turku, the University of Portsmouth, the
University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
- GCN Circular #37460
S.Q. Jiang, X. Liu, J. An, Z.P. Zhu, S.Y. Fu, D. Xu (NAOC), J.Z. Liu (XAO)
report on behalf of a large collaboration:
We observed the Swift/XRT ToO field (Evans, GCN 37456) of GRB 240910A detec=
ted by Fermi/GBM (Fermi GBM team, GCN 37441), SVOM/GRM (Zhang et al., GCN 3=
7445), and GRBAlpha (Ripa et al., GCN 37450), using the 100C telescope of t=
he JinShan project, located at Altay, Xinjiang, China. We obtained 8 x 300
s frames in the Sloan r-filter at a median time of 1.55 days after the Ferm=
i/GBM trigger.
An uncatalogued optical transient is detected within the Swift/XRT Source #=
2 error circle (01h36m23.32s, -00=C2=B012=E2=80=B217.1=E2=80=B3, radius ~ 4=
.0=E2=80=B2=E2=80=B2) at coordinates
R.A.(J2000) =3D 01:36:23.47
Dec.(J2000) =3D -00:12:17.24
with an uncertainty of ~ 0.4 arcsec, being consistent with the GOTO positio=
n (Julakanti et al., GCN 37459). It has r ~ 20.9 mag (AB), calibrated with
the nearby PanSTARRS stars. The decay rate of the OT, in comparison with th=
e previous GOTO brightness, is consistent with that for GRB optical aftergl=
ows. We thus conclude that the OT is very likely the optical afterglow of G=
RB 240910A.
We acknowledge the excellent support from X. Yao, S.W. Luo, and Z.K. Feng
for enabling these observations.
- GCN Circular #37461
A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), D.N. Burrows (PSU), M. A.
Williams (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.
Leicester), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB) and P.A.
Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/GBM-detected burst GRB 240910A (GCN Circ. 37441), centred on the
position of the candidate optical counterpart detected by GOTO:
GOTO24fvl/AT2024vfp (Julakanti et al., GCN Circ. 37459). XRT has
collected 1.9 ks of Photon Counting (PC) mode data between T0+128.3 ks
and T0+135.2 ks.
An uncatalogued X-ray source is found at the GOTO position. Its current
flux is below historical upper limits and we cannot currently confirm
fading; thus, based on X-ray data alone we cannot identify this as a
transient. However, given its coincidence with the GOTO source, we
suggest that is it likely to be the GRB afterglow.
Details of this source are given below:
Source 2:
RA (J2000.0): 24.0972 = 01:36:23.32
Dec (J2000.0): -0.2047 = -00:12:17.1
Error: 4.0 arcsec (radius, 90% conf. [Enhanced position])
Count-rate: 0.0182 +/- 0.0042 ct s^-1
Distance: 2 arcsec from GOTO position.
Flux: (7.3 +/- 1.7)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/00021712.
This circular is an official product of the Swift-XRT team.
- GCN Circular #37463
Daniele B. Malesani (DAWN/NBI and Radboud Univ.), Ben Gompertz (Birmingham) & Niilo Koivisto (NOT and UTU) report on behalf of a larger collaboration:
We observed the optical counterpart (Julakanti et al., GCN 37459; Jiang et al., GCN 37460; D'Ai et al., GCN 37461) of GRB 240910A (Fermi GBM team, GCN 37441; Zhang et al., GCN 37445) using the Nordic Optical Telescope (NOT) located in the Canary Islands. Observations began at high airmass, as soon as the target became observable.
In a 300 s image taken in the r band with mean time Sep 11.98 UT (1.425 days after the trigger), we measure for the optical counterpart a magnitude r = 21.4 +- 0.1 AB, calibrated against nearby Pan-STARRS objects.
- GCN Circular #37464
M. Godwin (UAH) reports on behalf of the Fermi GBM Team:
"At 04:00:44.21 UT on 10 September 2024, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 240910A (trigger 747633649 / 240910167) which was also detected by the
Swift/BAT (A. D'ai et al. 2024, GCN 37461) and GOTO (Julakanti et al., 2024, GCN 37459).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 101 degrees.
The GBM light curve consists of multiple peaks with a duration (T90)
of about 272 s (50-300 keV). The time-averaged spectrum
from T0+0 to T0+272.4 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.23 +/- 0.05 and the cutoff energy,
parameterized as Epeak, is 125 +/- 9 keV.
The event fluence (10-1000 keV) in this time interval is
(1.911 +/- 0.073)E-05 erg/cm^2. The 1s peak photon flux measured
starting from T0+86.1s in the 10-1000 keV band is 6.1 +/- 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/"
- GCN Circular #37467
A. de Ugarte Postigo (LAM/OCA, CNRS), J. F. Agui Fernandez (CAHA), C. C. Th=
oene (ASU-CAS), N. A. Rakotondrainibe (LAM), N. R. Tanvir (U. Leicester),
L. Izzo (INAF-Naples), S. Geier (GTC), G. Lombardi (GTC), J. P. U. Fynbo (D=
AWN/NBI), A. Martin-Carrillo (UCD), A. Garcia Rodriguez (GTC), A. Perez Ro=
mero (GTC) report,
We observed the afterglow (Julakanti et al. GCN 37459; D=E2=80=99Ai et al.
GCN 37461; Malesani et al. GCN 37463) of the long GRB 240910A, detected by
Fermi (Fermi team, GCN 37441), SVOM (Zhang et al. GCN 37445) and GRBAlpha (=
Ripa et al. GCN 37450) using OSIRIS+ mounted on the 10.4 m GTC telescope, a=
t the Roque de los Muchachos Observatory (La Palma, Spain). The observation
consisted in 3 acquisition images in r-band, followed by 3x1200 s spectra,
with grism R1000B, covering the spectral range between 3650 and 7800 AA at
a resolving power of 600. The spectra were obtained at a mean epoch 2024-0=
9-12T03:39:07 UT, 1.985 days after the Fermi trigger.
The continuum is well detected in the complete spectral range and there are
multiple features of CIV, FeII, AlII, AlIII, ZnII, MnII, MgII, MgI at a
common redshift of z = 1.460, which we propose as the redshift of the GRB.
- GCN Circular #37503
SVOM/VT commissioning team: Y. L.Qiu, L. P. Xin, H. L. Li, C. Wu, X. H. Han=
, W. J. Xie, H. B. Cai, Y. Xu, Y. J. Xiao, P. P. Zhang, J. S. Deng, 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) and Palmerio, J. (CEA).
SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (I=
HEP), St=C3=A9phane Basa (LAM), Jean-Luc Atteia (IRAP), Arnaud Claret (CEA)=
, Zi-Gao Dai (USTC), Fr=C3=A9d=C3=A9ric Daigne (IAP), Jin-Song Deng (NAOC),=
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), Bing Zhang (UNLV=
)
report on behalf of the SVOM team:
During the commissioning phase of SVOM mission, we observed the field of th=
e GRB 240910A (Fermi team, GCN 37441, Zhang et al. GCN 37445) with SVOM/VT =
telescope in ToO mode. The observation started at 24-09-12T13:51:13 UT, abo=
ut 57.8 hours after the burst, and lasted for about 2.7 ks. VT made the obs=
ervations with two channels simultaneously, VT_B (400nm-650nm) and VT_R (65=
0nm-1000nm).=20
The optical afterglow (Julakanti et al. GCN 37459; Jiang et al., GCN 37460;=
Malesani et al. GCN 37463; de Ugarte Postigo et al., GCN 37467) was detect=
ed in the VT stacked images, the magnitudes obtained by VT were: VT_B=3D22.=
24+/-0.07 mag, and VT_R=3D21.50+/-0.05 mag in AB magnitude.
More detailed analysis is ongoing.
=20
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 is an optical telescope on bo=
ard SVOM with an aperture of 44 cm, designed to automatically follow the Ec=
lairs triggers. It has two channels: VT_B and VT_R, covering wavelengths fr=
om 400 nm to 650 nm and 650 nm to 1000 nm, respectively. The two bands are =
observed simultaneously. VT was jointly developed by Xi'an Institute of Opt=
ics and Precision Mechanics (XIOPM), CAS and National astronomical observat=
ories (NAOC),CAS.
- GCN Circular #37553
P.A. Evans (U. Leicester), M.H. Siegel (PSU) and K.L. Page (U. Leicester)
report on behalf of the Swift-XRT and UVOT teams:
Swift has re-observed the putative afterglow of GRB 240910A, first
reported by Julakanti et al. (GCN Circ. 37459) at two additional epochs.
2.8 ks of data were taken between T0+282 ks and T0+329 ks, and a further
4.2 ks between T0+679 ks and T0+708 ks. The X-ray counterpart (D'Ai et
al., GCN Circ. 37461) clearly fades between epochs. The light curve can be
modelled with a power-law decay with a decay index of alpha=1.1 (+0.4,
-0.3).
UVOT observed the field in the u, v and white filters. A faint source was
detected in the first epoch at the XRT position with a u magnitude of
20.65 +/- 0.28 with a significance of 3.8 sigma. The second epoch detected
no counterpart to a 3 sigma upper limit of 21.51.
We therefore confirm that GOTO24fvl/AT2024vfp is the afterglow of GRB
240910A.
This circular is an official product of the Swift-XRT and UVOT teams.
- GCN Circular #37569
S. Giarratana (INAF-OAB), M. Giroletti (INAF-IRA),
G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),
N. Omodei (Stanford Univ.), O. S. Salafia (INAF-OAB)
At 05:42:45 UT on 2024 Sept 13 (T_mid = 3.10 days post-burst)
the Karl G. Jansky VLA observed the field of GRB 240910A
(Fermi GBM team, GCN 37441, 37464; SVOM team, GCN37445, 37503)
at a central frequency of 6, 10 and 15 GHz.
The standard 3C48 was used as bandpass and flux density
calibrator, while J0125-0005 was used as phase calibrator.
From a preliminary analysis, an unresolved radio source
is clearly detected at a position:
RA: 01:36:23.458 +- 0.003
Dec: -00:12:17.42 +- 0.05
consistent with the optical (GOTO collaboration, GCN 37459;
Jiang et al., GCN 37460) and X-ray (D'Ai et al., GCN 37461)
transient.
The surface brightness peak is 137 uJy/beam, 114 uJy/b and
86 uJy/beam at 6, 10 and 15 GHz, respectively.
The r.m.s. noise level of the images is 7 uJy/beam at 6 GHz,
7 uJy/b at 10 GHz and 9 uJy/b at 15 GHz.
The synthesized beams are 1.36x1.01 arcsec (PA: -48deg)
at 6 GHz, 0.79x0.63 arcsec (PA: -50deg) at 10 GHz
and 0.61x0.43 arcsec (PA: -56deg) at 15 GHz.
While no source is detected with a 3sigma confidence at the
aforementioned position in previous radio surveys (FIRST, NVSS,
VLASS, RACS), their r.m.s. noise levels (1sigma) is above
100 uJy/b. Therefore, we cannot exclude the contribution from
the GRB host galaxy yet.
We would like to thank the staff of the VLA for approving, executing,
and processing the observations.
The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc.
These observations were carried out as part of project SF171028,
approved in the framework of the Fermi - NRAO joint program agreement.
- GCN Circular #37734
A. Rossi, E. Maiorano (INAF-OAS), and D. B. Malesani (DAWN/NBI and Radboud
Univ.), report on behalf of the CIBO collaboration:
We observed the field of GRB 240910A (Zhang et al. GCN 37445; Ripa et al. GCN
37450; Godwin, GCN 37464) with the LBC camera mounted on LBT (Mt. Graham,
AZ, USA) in r=E2=80=99 and z=E2=80=99 bands (15 min exposure time per
filter) approximately at midtime 06:20:00 UT on 2024-09-26 (16.1 days after
the burst). Observations were performed under mediocre weather conditions and
an average seeing of ~1.7".
At the location of the afterglow (Julakanti et al. GCN 37459; Jiang et al.
GCN 37460; D=E2=80=99Ai et al. GCN 37461; Malesani et al. GCN 37463; Qiu
et al. GCN 37503; Evans et al., GCN 37553; Giarratana et al., GCN 37569) we
detect a faint source with the following AB magnitudes:
r' = 26.1 +- 0.4,
z' > 24.4,
calibrated against SDSS field stars, and not corrected for foreground Galactic
extinction.
We acknowledge the excellent support from the LBTO and LBT-INAF staff,
particularly F. Cusano and D.Paris in obtaining these observations.
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