Gamma-ray Burst 241105A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 05 Nov 24 16:06:34 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      45
TRIGGER_NUM:     752515569
GRB_RA:           84.183d {+05h 36m 44s} (J2000),
                  84.351d {+05h 37m 24s} (current),
                  83.845d {+05h 35m 23s} (1950)
GRB_DEC:         -47.517d {-47d 31' 00"} (J2000),
                 -47.503d {-47d 30' 09"} (current),
                 -47.546d {-47d 32' 44"} (1950)
GRB_ERROR:       9.45 [deg radius, statistical plus systematic]
GRB_INTEN:       278 [cnts/sec]
DATA_SIGNIF:     8.60 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        20619 TJD;   310 DOY;   24/11/05
GRB_TIME:        57964.66 SOD {16:06:04.66} UT
GRB_PHI:         156.00 [deg]
GRB_THETA:       155.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.33
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,0,0, 0,0,0, 1,0,0, 0,1,0, 0,0,
SUN_POSTN:       221.28d {+14h 45m 07s}  -15.96d {-15d 57' 34"}
SUN_DIST:        105.77 [deg]   Sun_angle= 9.1 [hr] (West of Sun)
MOON_POSTN:      270.66d {+18h 02m 39s}  -28.61d {-28d 36' 51"}
MOON_DIST:       103.67 [deg]
MOON_ILLUM:      16 [%]
GAL_COORDS:      254.01,-31.92 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       78.04,-70.71 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241105671/quicklook/glg_lc_medres34_bn241105671.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 45.50,7.53 [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 05 Nov 24 16:06:51 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     752515569
GRB_RA:           68.580d {+04h 34m 19s} (J2000),
                  68.751d {+04h 35m 00s} (current),
                  68.237d {+04h 32m 57s} (1950)
GRB_DEC:         -48.940d {-48d 56' 23"} (J2000),
                 -48.890d {-48d 53' 22"} (current),
                 -49.042d {-49d 02' 32"} (1950)
GRB_ERROR:       5.26 [deg radius, statistical only]
DATA_SIGNIF:     11.60 [sigma]
DATA_INTERVAL:   0.512 [sec]
GRB_DATE:        20619 TJD;   310 DOY;   24/11/05
GRB_TIME:        57964.66 SOD {16:06:04.66} UT
GRB_PHI:         145.00 [deg]
GRB_THETA:       146.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       221.28d {+14h 45m 07s}  -15.96d {-15d 57' 34"}
SUN_DIST:        110.71 [deg]   Sun_angle= 10.2 [hr] (West of Sun)
MOON_POSTN:      270.67d {+18h 02m 40s}  -28.61d {-28d 36' 51"}
MOON_DIST:       100.06 [deg]
MOON_ILLUM:      16 [%]
GAL_COORDS:      255.72,-42.31 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       47.42,-69.23 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241105671/quicklook/glg_lc_medres34_bn241105671.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_752515569.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 05 Nov 24 16:15:22 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     752515569
GRB_RA:           61.940d {+04h 07m 46s} (J2000),
                  62.129d {+04h 08m 31s} (current),
                  61.560d {+04h 06m 14s} (1950)
GRB_DEC:         -46.660d {-46d 39' 35"} (J2000),
                 -46.595d {-46d 35' 41"} (current),
                 -46.792d {-46d 47' 29"} (1950)
GRB_ERROR:       4.03 [deg radius, statistical only]
GRB_DATE:        20619 TJD;   310 DOY;   24/11/05
GRB_TIME:        57964.66 SOD {16:06:04.66} UT
GRB_PHI:         145.00 [deg]
GRB_THETA:       141.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       221.29d {+14h 45m 09s}  -15.96d {-15d 57' 41"}
SUN_DIST:        114.69 [deg]   Sun_angle= 10.6 [hr] (West of Sun)
MOON_POSTN:      270.75d {+18h 03m 00s}  -28.61d {-28d 36' 52"}
MOON_DIST:       100.46 [deg]
MOON_ILLUM:      16 [%]
GAL_COORDS:      253.39,-47.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       39.53,-65.26 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241105671/quicklook/glg_lc_medres34_bn241105671.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241105671/quicklook/glg_locplot_all_bn241105671.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 Short GRB.

GCN Circular #38085
The Fermi GBM team reports the detection of a likely SHORT GRB
At 16:06:04 UT on 5 Nov 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241105A (trigger 752515569.657898 / 241105671).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 61.9, Dec = -46.7 (J2000 degrees, equivalent to J2000 04h 07m, -46d 42'), with a statistical uncertainty of 4.0 degrees.
The angle from the Fermi LAT boresight is 141.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241105671/quicklook/glg_skymap_all_bn241105671.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/bn241105671/quicklook/glg_healpix_all_bn241105671.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241105671/quicklook/glg_lc_medres34_bn241105671.gif

GCN Circular #38087
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
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 241105A ( Fermi GBM team, GCN 38085) errorbox 6515 sec after notice time and 6547 sec after trigger time at 2024-11-05 17:55:11 UT, with upper limit up to 18.8 mag. Observations started at twilight. The observations began at zenith distance = 64 deg. The sun altitude is -10.2 deg.
The galactic latitude b = -47 deg., longitude l = 253 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2659513
We obtain a following upper limits.

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

    6577 | 2024-11-05 17:55:11 |         MASTER-SAAO | (03h 52m 33.36s , -46d 21m 11.7s) |   C |    60 | 17.1 |        
    6657 | 2024-11-05 17:56:31 |         MASTER-SAAO | (04h 04m 03.57s , -46d 21m 40.7s) |   C |    60 | 17.2 |        
    6736 | 2024-11-05 17:57:50 |         MASTER-SAAO | (04h 01m 08.30s , -48d 13m 54.1s) |   C |    60 | 17.5 |        
    6816 | 2024-11-05 17:59:10 |         MASTER-SAAO | (04h 13m 10.67s , -48d 15m 03.6s) |   C |    60 | 17.4 |        
    6895 | 2024-11-05 18:00:29 |         MASTER-SAAO | (04h 05m 59.51s , -44d 26m 39.6s) |   C |    60 | 17.6 |        
    6976 | 2024-11-05 18:01:50 |         MASTER-SAAO | (04h 17m 13.95s , -44d 25m 09.3s) |   C |    60 | 17.6 |        
    7055 | 2024-11-05 18:03:09 |         MASTER-SAAO | (04h 14m 31.28s , -46d 21m 16.5s) |   C |    60 | 17.6 |        
    7134 | 2024-11-05 18:04:28 |         MASTER-SAAO | (04h 26m 13.67s , -46d 20m 43.5s) |   C |    60 | 17.5 |        
    7214 | 2024-11-05 18:05:48 |         MASTER-SAAO | (03h 44m 41.50s , -44d 28m 36.3s) |   C |    60 | 17.8 |        
    7293 | 2024-11-05 18:07:07 |         MASTER-SAAO | (03h 55m 58.67s , -44d 26m 32.4s) |   C |    60 | 18.0 |        
    7372 | 2024-11-05 18:08:26 |         MASTER-SAAO | (03h 38m 11.25s , -48d 14m 55.3s) |   C |    60 | 18.0 |        
    7451 | 2024-11-05 18:09:46 |         MASTER-SAAO | (03h 50m 20.15s , -48d 15m 26.8s) |   C |    60 | 18.4 |        
    7531 | 2024-11-05 18:11:05 |         MASTER-SAAO | (03h 46m 56.99s , -50d 10m 11.8s) |   C |    60 | 18.3 |        
    7610 | 2024-11-05 18:12:24 |         MASTER-SAAO | (03h 59m 25.26s , -50d 08m 21.7s) |   C |    60 | 18.3 |        
    7689 | 2024-11-05 18:13:43 |         MASTER-SAAO | (04h 10m 43.68s , -50d 07m 51.8s) |   C |    60 | 18.3 |        
    7768 | 2024-11-05 18:15:03 |         MASTER-SAAO | (04h 23m 07.88s , -50d 08m 01.9s) |   C |    60 | 18.4 |        
    7848 | 2024-11-05 18:16:22 |         MASTER-SAAO | (03h 58m 19.99s , -42d 33m 17.4s) |   C |    60 | 18.2 |        
    7927 | 2024-11-05 18:17:41 |         MASTER-SAAO | (04h 09m 06.24s , -42d 33m 50.3s) |   C |    60 | 18.3 |        
    8006 | 2024-11-05 18:19:00 |         MASTER-SAAO | (04h 23m 58.35s , -48d 13m 20.0s) |   C |    60 | 18.3 |        
    8085 | 2024-11-05 18:20:20 |         MASTER-SAAO | (04h 36m 00.54s , -48d 14m 30.1s) |   C |    60 | 18.5 |        
    8244 | 2024-11-05 18:22:58 |         MASTER-SAAO | (03h 41m 56.11s , -46d 21m 00.2s) |   C |    60 | 17.9 |        
    8323 | 2024-11-05 18:24:18 |         MASTER-SAAO | (03h 56m 28.91s , -52d 04m 20.1s) |   C |    60 | 17.9 |        
    8403 | 2024-11-05 18:25:37 |         MASTER-SAAO | (04h 09m 37.47s , -52d 03m 44.2s) |   C |    60 | 17.8 |        
    8483 | 2024-11-05 18:26:57 |         MASTER-SAAO | (03h 52m 26.77s , -46d 21m 00.4s) |   C |    60 | 18.5 |        
    8563 | 2024-11-05 18:28:17 |         MASTER-SAAO | (04h 04m 03.53s , -46d 21m 51.6s) |   C |    60 | 18.1 |        
    8642 | 2024-11-05 18:29:37 |         MASTER-SAAO | (04h 01m 07.56s , -48d 14m 42.4s) |   C |    60 | 18.6 |        
    8722 | 2024-11-05 18:30:56 |         MASTER-SAAO | (04h 13m 02.89s , -48d 14m 47.3s) |   C |    60 | 18.5 |        
    8801 | 2024-11-05 18:32:15 |         MASTER-SAAO | (04h 05m 56.42s , -44d 26m 10.5s) |   C |    60 | 18.3 |        
    8881 | 2024-11-05 18:33:35 |         MASTER-SAAO | (04h 17m 16.54s , -44d 26m 41.2s) |   C |    60 | 18.5 |        
    8960 | 2024-11-05 18:34:54 |         MASTER-SAAO | (04h 14m 27.93s , -46d 21m 48.3s) |   C |    60 | 18.2 |        
    9040 | 2024-11-05 18:36:14 |         MASTER-SAAO | (04h 26m 09.61s , -46d 21m 02.0s) |   C |    60 | 18.2 |        
    9119 | 2024-11-05 18:37:33 |         MASTER-SAAO | (03h 44m 37.51s , -44d 27m 17.4s) |   C |    60 | 18.2 |        
    9198 | 2024-11-05 18:38:52 |         MASTER-SAAO | (03h 55m 51.33s , -44d 28m 14.8s) |   C |    60 | 18.3 |        
    9277 | 2024-11-05 18:40:12 |         MASTER-SAAO | (03h 38m 11.92s , -48d 15m 26.4s) |   C |    60 | 18.0 |        
    9357 | 2024-11-05 18:41:31 |         MASTER-SAAO | (03h 50m 09.49s , -48d 15m 52.5s) |   C |    60 | 18.5 |        
    9437 | 2024-11-05 18:42:51 |         MASTER-SAAO | (03h 46m 45.81s , -50d 08m 59.1s) |   C |    60 | 18.5 |        
    9516 | 2024-11-05 18:44:10 |         MASTER-SAAO | (03h 59m 23.29s , -50d 09m 31.6s) |   C |    60 | 18.3 |        
    9596 | 2024-11-05 18:45:30 |         MASTER-SAAO | (04h 10m 34.05s , -50d 10m 05.8s) |   C |    60 | 18.2 |        
    9675 | 2024-11-05 18:46:49 |         MASTER-SAAO | (04h 23m 09.90s , -50d 09m 09.7s) |   C |    60 | 18.5 |        
    9755 | 2024-11-05 18:48:09 |         MASTER-SAAO | (03h 58m 13.38s , -42d 32m 56.7s) |   C |    60 | 18.2 |        
    9834 | 2024-11-05 18:49:28 |         MASTER-SAAO | (04h 09m 06.18s , -42d 34m 09.9s) |   C |    60 | 18.2 |        
    9913 | 2024-11-05 18:50:47 |         MASTER-SAAO | (04h 23m 57.77s , -48d 13m 55.9s) |   C |    60 | 18.5 |        
    9993 | 2024-11-05 18:52:07 |         MASTER-SAAO | (04h 35m 53.00s , -48d 14m 05.5s) |   C |    60 | 18.5 |        
   10152 | 2024-11-05 18:54:46 |         MASTER-SAAO | (03h 41m 57.58s , -46d 22m 20.5s) |   C |    60 | 18.3 |        
   10232 | 2024-11-05 18:56:06 |         MASTER-SAAO | (03h 56m 24.35s , -52d 04m 43.4s) |   C |    60 | 18.4 |        
   10311 | 2024-11-05 18:57:25 |         MASTER-SAAO | (04h 09m 32.32s , -52d 04m 06.1s) |   C |    60 | 18.3 |        
   10390 | 2024-11-05 18:58:45 |         MASTER-SAAO | (03h 52m 22.68s , -46d 21m 14.9s) |   C |    60 | 18.3 |        
   10470 | 2024-11-05 19:00:04 |         MASTER-SAAO | (04h 03m 59.52s , -46d 22m 15.7s) |   C |    60 | 18.4 |        
   10551 | 2024-11-05 19:01:25 |         MASTER-SAAO | (04h 01m 02.42s , -48d 15m 05.8s) |   C |    60 | 18.7 |        
   10630 | 2024-11-05 19:02:44 |         MASTER-SAAO | (04h 12m 59.57s , -48d 15m 12.2s) |   C |    60 | 18.6 |        
   10709 | 2024-11-05 19:04:03 |         MASTER-SAAO | (04h 05m 51.88s , -44d 26m 33.5s) |   C |    60 | 18.7 |        
   10789 | 2024-11-05 19:05:23 |         MASTER-SAAO | (04h 17m 11.88s , -44d 27m 07.7s) |   C |    60 | 18.6 |        
   10868 | 2024-11-05 19:06:42 |         MASTER-SAAO | (04h 14m 22.87s , -46d 22m 12.9s) |   C |    60 | 18.2 |        
   10947 | 2024-11-05 19:08:01 |         MASTER-SAAO | (04h 26m 06.96s , -46d 21m 32.8s) |   C |    60 | 18.4 |        
   11026 | 2024-11-05 19:09:21 |         MASTER-SAAO | (03h 44m 33.66s , -44d 27m 37.1s) |   C |    60 | 18.6 |        
   11106 | 2024-11-05 19:10:40 |         MASTER-SAAO | (03h 55m 47.50s , -44d 28m 33.3s) |   C |    60 | 18.4 |        
   11185 | 2024-11-05 19:11:59 |         MASTER-SAAO | (03h 38m 08.44s , -48d 15m 57.5s) |   C |    60 | 18.5 |        
   11264 | 2024-11-05 19:13:18 |         MASTER-SAAO | (03h 50m 05.58s , -48d 16m 07.8s) |   C |    60 | 18.8 |        
   11344 | 2024-11-05 19:14:38 |         MASTER-SAAO | (03h 46m 41.33s , -50d 09m 12.6s) |   C |    60 | 18.8 |        
   11423 | 2024-11-05 19:15:57 |         MASTER-SAAO | (03h 59m 18.24s , -50d 09m 48.0s) |   C |    60 | 18.6 |        
   11502 | 2024-11-05 19:17:16 |         MASTER-SAAO | (04h 10m 28.92s , -50d 10m 24.3s) |   C |    60 | 18.7 |        
   11583 | 2024-11-05 19:18:37 |         MASTER-SAAO | (04h 23m 04.83s , -50d 09m 40.0s) |   C |    60 | 18.5 |        
   11662 | 2024-11-05 19:19:56 |         MASTER-SAAO | (03h 58m 09.51s , -42d 33m 04.0s) |   C |    60 | 18.2 |        
   11741 | 2024-11-05 19:21:15 |         MASTER-SAAO | (04h 09m 02.46s , -42d 34m 34.8s) |   C |    60 | 18.4 |        
   11821 | 2024-11-05 19:22:35 |         MASTER-SAAO | (04h 23m 52.36s , -48d 14m 16.6s) |   C |    60 | 18.7 |        
   11900 | 2024-11-05 19:23:54 |         MASTER-SAAO | (04h 35m 49.05s , -48d 14m 29.2s) |   C |    60 | 18.7 |

Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

GCN Circular #38088
Y. Julakanti, G. Ramsay, B. P. Gompertz, K. Ackley, D. O'Neill, A. Kumar, R. Starling, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, 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 optical observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022; Dyer et al. 2024) in response to the GRB 241105A (Fermi GBM Team, GCN 38085). Targeted imaging covered the Fermi localisation region from 2024-11-05 16:19:10 UT, (+0.22h post trigger) to 2024-11-05 17:42:50 UT (+1.61h post trigger). In total, 277.9 square degrees within the 90% contour were imaged, resulting in a coverage total of ~84.3% of the total 2D localisation probability. The observations consisted of 4x90s exposures in the GOTO L-band (400-700 nm). In total, 101 images were taken, across 10 unique pointings, with an average 5-sigma depth of 20.4 mag.
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogs. Human vetting was carried out in real time on any candidates that passed the above checks.
A new optical source GOTO24ibf is identified within the GBM 90% localisation region. We find no evidence of the source down to 20.0 mag prior to the GRB trigger time in previous GOTO observations taken at 2024-11-05 10:48:54 UTC (t-t0 = -5.29h) or the ATLAS forced photometry server (Shingles et al. 2021). There is a faint ambiguous underlying source at the position of GOTO24ibf visible in DESI legacy survey images that we cannot definitively identify as a star or galaxy. Due to the onset of twilight at Siding Spring Observatory, only a single epoch of observations were obtained, preventing any assessment of the evolution of the source. We encourage further deeper follow-up observations.
```
+-------------------------------------------------------------------------------------------------------+
|  Internal name |  Time (UT) | t-t0 (h) | RA (J2000) |  Dec (J2000) |      Mag      |
+-------------------------------------------------------------------------------------------------------+

|  GOTO24ibf   | 2024-11-05 16:34:35  | 0.48 | 04:24:59.0 | -49:45:09.3 | 17.21 +/- 0.01 |
```
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular #38091
James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 241105A onboard (T0: 2024-11-05T16:06:04 UTC= , Fermi GCN 38085).
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).=20
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 position of the burst is found via BAT imaging with SNR of 11. The position is: RA, Dec =3D 66.2381, -49.7547 deg which is
```
   RA(J2000)  = 04h 24m 57.14s
   Dec(J2000) = -49d 45=E2=80=B2 16.9=E2=80=B3
```
with an estimated uncertainty of 3 arcmin radius.
This BAT-GUANO position is coincident with the optical transient discovered by GOTO (GCN 38088).
XRT and UVOT follow-up has been triggered. Results of follow-up observations will be reported in future circulars.
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/
GCN Circular #38092
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/GBM GRB 241105A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021728
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 #38097
L. Izzo (INAF-OACn & DARK/NBI), A. A. Chrimes (ESA/ESTEC & Radboud Univ.), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Saccardi (CEA/Irfu), A. Martin-Carrillo (UCD), A. J. Levan (Radboud Univ. and Warwick Univ.), B. P. Gompertz (Birmingham), N. R. Tanvir (U. Leicester), report on behalf of the Stargate collaboration:
We observed the proposed optical counterpart (Julakanti et al., GCN 38088) of GRB 241105A (Fermi GBM team, GCN 38085; DeLaunay et al., GCN 38091). We used the FORS2 spectrograph mounted on the ESO VLT UT1 (Antu), equipped with grisms 300V (without order-sorting filter) and 300I (with filter OG590). The exposure time was 600 s per grism. Spectroscopy started on 2024 November 6.133 UT (about 11.08 hr after the trigger), and was carried out through moderately good seeing conditions (1").
In the acquisition image, we measure a preliminary magnitude R = 20.10 +/- 0.10 (Vega), calibrated using archival FORS2 zeropoints.
From a preliminary reduction of the 300V spectrum, a continuum is detected over the wavelength range 4600 to 8700 AA. A trough due to Lya absorption is visible at the blue end. From the detection of multiple absorption features, which we interpret as due to C II, C IV, Si II, Si IV, Al II, Al III and Fe II, we infer a redshift of z = 2.702.
We acknowledge the excellent support from the ESO staff in Paranal, in particular Maria Jose Rain and Israel Blanchard.
GCN Circular #38098
J.A. Kennea (PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), M. A. Williams (PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the BAT/GUANO localisation of the Fermi/GBM-detected burst GRB 241105A, collecting 3.9 ks of Photon Counting (PC) mode data between T0+38.3 ks and T0+62.2 ks.
Two uncatalogued X-ray sources are detected consistent with being within 296 arcsec of the BAT/GUANO position, of which one ("Source 1") is fading with 2.2 sigma significance and thus is believed to be the GRB afterglow. Using 794 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 66.24484, -49.75181 which is equivalent to:
```
RA (J2000): 04h 24m 58.76s
Dec(J2000): -49d 45' 06.5"
```
with an uncertainty of 4.9 arcsec (radius, 90% confidence). This position is 18 arcsec from the BAT/GUANO position (DeLaunay et al., GCN Circ. 38091), and is consistent with the GOTO optical counterpart (Julakanti et al., GCN Circ. 38088).
The light curve can be modelled with a power-law decay with a decay index of alpha=3.32 (+0.05, -2.26).
If the light curve continues to decay with a power-law decay index of 3.32, the count rate at T+24 hours will be 1.8 x 10^-3 count s^-1
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021728. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021728.
This circular is an official product of the Swift-XRT team.
GCN Circular #38099
SVOM/VT commissioning team: Y. L. Qiu, H. L. Li, L. P. Xin, C. Wu, 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), W. K. Zheng (UCB), = Z. Q. Wang (GXU)
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),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), Shao-Lin Xiong (I= HEP), Bing Zhang (UNLV)
report on behalf of the SVOM team:
VT started to observe the optical counterpart (Julakanti et al., GCN 38088;= Izzo et al., GCN 38097) of GRB 241105A (Fermi GBM team, GCN 38085; DeLaun= ay et al., GCN 38091) in ToO mode from 2024-11-06T06:18:32 UT, about 14.2 h= ours after the burst. The VT conducted observations in VT_B band (400-650nm= ) and VT_R band (650-1000nm) simultaneously.
The afterglow was clearly detected in both bands with the brightness of VT_= B =3D 20.94 +/- 0.04 mag and VT_R =3D 19.92 +/- 0.03 mag in AB magnitude at= the midtime of 14.36 hours after the burst.
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 #38103
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The likely short GRB 241105A (Fermi GBM team, GCN 38085) triggered Konus-Wind (KW) at T0=3D57966.516 s UT (16:06:06.516).
The burst light curve shows a short initial pulse, which starts at ~T0-0.5 s, peaks at ~T0, and has a total duration of ~1.5 s, which was followed by a weaker extended emission, visible in KW up to ~T0+60 s. The emission is seen up to ~4 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB241105_T57966/
As observed by Konus-Wind, the burst had a fluence of (2.01 =C2=B1 0.47)x10^-5 erg/cm^2 and a 64-ms peak energy flux, measured from T0 - 0.064 s, of (2.37 =C2=B1 0.30)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy = range).
The time-integrated spectrum (measured from T0 to T0+57.640 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 -0.69 (-0.37,+0.67), the high energy photon index beta =3D -1.76 (-0.55,+0.21), the peak energy Ep =3D 374 (-165,+437) keV, chi2 = 98/97 dof.
The spectrum of the initial pulse alone (measured from T0-0.512 s to T0+0.9= 60 s) can be described by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha =3D -0.90(-0.15,+0.15) and Ep =3D 417(-82,+111) keV.
Assuming the redshift z=3D2.702 (Izzo et al., GCN 38097) and a standard cosmology with H_0 =3D 67.3 km/s/Mpc, Omega_M =3D 0.315, and Omega_Lambda =3D 0.685 (Planck Collaboration, 2014), we estimate the burst isotropic energy release E_iso to (3.42 =C2=B1 0.80)x= 10^53 erg, the isotropic peak luminosity L_iso to (1.49 =C2=B1 0.18)x10^53 erg/s, the rest-frame peak energy of the time-integrated spectrum Ep,i,z to ~1380 = keV, and the rest-frame peak energy at the peak of the emission Ep,p,z to ~1540 = keV. With the obtained estimates, GRB 241105A fits 68% prediction bands for both 'Amati' and 'Yonetoku' relations derived for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 202= 1), see http://www.ioffe.ru/LEA/GRBs/GRB241105_T57966/GRB241105A_rest_frame.pdf
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.
GCN Circular #38104
U. Pathak (IITB), O. Mukherjee (USRA), S. Rushikesh (IISER, TVM), S. Bala (USRA), O.J. Roberts (USRA/NASA-MSFC), E. Burns (LSU), P. Veres (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 16:06:04.66 UT on 05 November 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB241105A (trigger 752515569/241105671), which was also detected by Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 38091), GOTO (Julakanti et al. 2024, GCN 38088), Swift-XRT (Kennea et al. 2024, GCN 38098), and SVOM/VT (Qiu et al. 2024, GCN 38099). The spectroscopic redshift of the optical counterpart observered by VLT/FORS2 (Izzo et al. 2024, GCN 38097) is 2.702.
The Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position.
The angle from the Fermi LAT boresight is 145 degrees.
The GBM light curve consists of a short single pulse with a duration (T90) of about 1.4 s (50-300 keV) followed by significant extended emission for ~91 (50-300 keV) seconds. The extended emission appears to contain more fluence than the initial spike. The time-averaged spectrum from T0-0.5 to T0+2.6 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.2 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 702 +/- 278 keV. Considering the redshift of 2.702, and best fit model, we find the isotropic equivalent luminosity Liso = 7.5e+52 erg s-1 (1-10000 keV).
The event fluence (10-1000 keV) in this time interval is (2.8 +/- 0.2)E-06 erg/cm^2. The 64-ms peak photon flux measured starting from T0-0.19 s in the 10-1000 keV band is 11 +/- 3 ph/s/cm^2.
The total emission (short pulse + extended emission) from T0-2.6 to T0+97 s is best fit by a power law function with photon index -1.42 +/- 0.04. The total fluence (10-1000 keV) in this time interval is (1.1 +/- 0.1)E-05 erg/cm^2. Using z=2.702, we find Eiso = 1.5e+53 erg (1-10000 keV) when fitting the spectrum with a power law function with an exponential high-energy cutoff, with a power-law index of -0.03 +/- 0.4 and cutoff energy, parameterized as Epeak, of 221 +/- 30 keV.
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 #38106
Y.-D. Hu (INAF-OAB), I. Perez-Garcia, A. J. Castro-Tirado, E. Fernandez-Garcia, S.-Y. Wu, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga), L. Hernandez-Garcia (Univ. de Valparaiso), M. Gritsevich (Univ. of Helsinki), D. R. Xiong (Yunnan Observatories of CAS), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), on behalf of a larger collaboration, report:
Following the detection of GRB 241105A by Fermi (Fermi GBM team, GCNC 38085) and Swift (DeLaunay et al. GCNC 38091; Kennea et al., GCNC 38098), we triggered the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama celestial observations in San Pedro de Atacama (Chile) to observe the burst position on Nov. 6 at 01:58 UT (i.e. ~ 9.9 hrs after trigger). A series of images was obtained with multi-bands. In the co-added image (11 x 60 s, SDSS-r filter), the optical afterglow reported by GOTO (Julakanti et al. GCNC 38088), VLT (Izzo et al., GCNC 38097) and SVOM/VT (Qiu et al., GCNC 38099) is detected with r=19.2+-0.2 mag.
We thank the staff at San Pedro de Atacama celestial observations for their excellent support.
GCN Circular #38108
James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT GUANO detected and localized GRB 241105A (GCN 38091). GRB 241105A was also detected by Fermi/GBM (GCN 38104), GOTO (GCN 38088), Swift-XRT (GCN 38098), SVOM/VT (GCN 38099), VLT/FORS2 (GCN 38097), and Konus-Wind (GCN 38103).
The burst was detected at a partial coding fraction of 14%.
The mask-weighted light curve shows a short, strong pulse with a duration of ~2 s followed by a longer extended emission with a duration of ~75 s. Consistent with what was observed by both Fermi/GBM (GCN 38104) and Konus-Wind (GCN 38103). T90 (15 - 350 keV) is 72.8 s +/- 9.7 s .
The time-average spectrum over T100 from T0 - 0.5 s to T0 + 77.8 s is best fit by a simple power-law with an index of 1.33 +/- 0.20. The 15 - 150 keV fluence is 2.5 +/- 0.3 x 10^-6 erg/cm2.
Both the initial spike and the extended emission are best fit by simple power-laws with consistent spectral indices. ~77% of the fluence is contained in the extended emission.
The initial spike (T0 - 1.1 s to T0 + 1.3 s) has a best fit spectral index of 1.65 +/- 0.20 with a 15 - 150 keV fluence of 5.6 +/- 0.7 x 10^-7 erg/cm2.
The extended emission (T0 + 1.3 s to T0 + 77.8 s) has a best fit spectral index of 1.26 +/- 0.25 with a 15 - 150 keV fluence of 1.9 +/- 0.3 x 10^-6 erg/cm2.
GCN Circular #38110
M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 241105A 38.4 ks after the Fermi trigger (GCN Circ. 38085). A faint fading source is detected consistent with the XRT position (Kennea et al., GCN Circ. 38098) and the reported optical counterparts (Julakanti et al., GCN Circ. 38088, Izzo, GCN. Circ. 38097, Wei et al., GCN Circ. 38099, Hu et al., GCN Circ 38106).
The preliminary UVOT position is:
```
    RA  (J2000) =  04:24:58.96 =  66.24568 (deg.)
    Dec (J2000) = -49:45:09.8  = -49.75271 (deg.)
```
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
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            38363        67383         4551      21.46+/-0.11
white            90644       106641         4612            >22.76
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.011 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #38111
Simone Dichiara (PSU), Eleonora Troja (U Rome), Rosa L. Becerra (U Rome), Yu-Han Yang (U Rome) report:
We observed the field of GRB 241105A (Fermi GBM team, GCN 38085; DeLaunay et al., GCN 38091; Konus-Wind team, GCN 38103) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began 1.5 days after the trigger and were carried out in the R and z filters through good seeing conditions (0.8").
We detect the optical counterpart (Julakanti et al., GCN 38088) at a preliminary magnitude R ~22.5 AB mag calibrated using nearby stars in the Legacy Survey DR10 (Dey et al. 2019). Compared with earlier optical detections (Julakanti et al., GCN 38088; SVOM/VT team, GCN 38099; Izzo et al. GCN 38097; Hu et al., GCN 38106), our observations show a rapid decline of the afterglow brightness, consistent with a power-law of slope ~-1.7.
Further observations are planned.
We thank the staff at the VLT, especially Maria Jose Rain, for the rapid execution of these observations.
GCN Circular #38113
J. Rastinejad, C. Kilpatrick, W. Fong (Northwestern) report on behalf of a larger collaboration:
We observed the location of the X-ray (Kennea et al. GCN 38098) and optical (Julakanti et al., GCN 38088) counterparts of GRB 241105A (Fermi GBM Team GCN 38085, DeLaunay et al. GCN 38091, Frederiks et al. GCN 38103) with the Gemini Multi-Object Spectrograph (GMOS) mounted on Gemini-South under Program GS-2024B-Q-108 (PI: Fong). We obtained 8x120-sec imaging in r-band at a mid-time of 2024-11-07 01:44:56.1 UT (1.4 days post-burst), at a median airmass of 1.6.
We clearly detect the optical afterglow. Calibrated to SkyMapper, we measure a preliminary brightness of r~21.7 AB mag at seeing < 1.1'', not corrected for Galactic extinction nor emission from the underlying galaxy (Izzo et al. 38097). Compared to the measurement of r=19.2 +/- 0.2 AB mag at 0.4 days reported by Hu et al. (GCN 38106), our observation indicates a rapid rate of decay (Fopt ~ t^-1.8). This decline rate is potentially contaminated by the host galaxy, and the true decline rate may be steeper. While the inferred magnitude differs by ~0.8 mag from the R-band measurement of Dichiara et al. (GCN 38111), we deduce similar decline rates in slightly different filters.
Further observations are planned to monitor the variability of the source. We thank Jennifer Andrews and additional Gemini staff for the rapid planning and execution of these observations.
GCN Circular #38119
K. Tsalapatas, Y. Hu, P. J. Pessi (Stockholm), P. D'Avanzo (INAF-OAB), D. B= . Malesani (DAWN/NBI and Radboud univ.), A. Gangopadhyay, A. Singh, A. Gkin= i, J. Sollerman, S. Barmentloo (Stockholm), T. Kravtsov (Turku), G. Pignata= (UTA), J. Anderson (ESO), T.-W. Chen (NCU), M. Gromadzki (Warsaw), C. Inse= rra (Cardiff), E. Kankare (Turku), T. M=C3=BCller Bravo (Trinity), O. Yaron= (Weizmann), D. Young (QUB), S. Benetti (INAF), E. Zimmerman (Weizmann), As= af Horowicz (Weizmann), J. Tonry, L. Denneau, H. Weiland, A. Lawrence, R. S= iverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Ast= ronomical Observatory), A. Jordan, V. Suc (UAI, Obstech), S. J. Smartt (Oxf= ord/QUB), K. W. Smith, S. Srivastav, D. R. Young, M. Fulton, M. McCollum, T= . Moore, M. Nicholl, J. Weston (QUB), L. Shingles (GSI/QUB), L. Rhodes (Oxf= ord), J. Sommer (LMU/QUB), A. Rest (STScI), C. Stubbs (Harvard) report:
We observed the field of GRB 241105A (Fermi GBM team, GCN 38085; DeLaunay e= t al., GCN 38091; Frederiks et al., GCN 38103) under the advanced Public ES= O Spectroscopic Survey for Transient Objects (ePESSTO+; see Smartt et al. 2= 015, A&A, 579, 40; http://www.pessto.org). The observations were performed = with the ESO New Technology Telescope (NTT) at La Silla equipped with the E= FOSC2 instrument in imaging mode, starting on 2024 Nov 06 at 03:21:27 UT (i= .e. about 1.47 days after the burst) using the r and z gunn filters.=20
The optical afterglow (Julakanti et al., GCN 38088) is clearly detected in both bands. From preliminary photometry, we estimate a magnitude of r = 22.4 +/- 0.1 (AB; calibrated against the ATLAS REFCAT2 catalogue; Tonry et al. 2018). This result is in agreement with the report from Dichiara et al. (GCN 38111).
GCN Circular #38121
J. Durbak (UMD), O. Guiffreda (UMD), S. Atri (U Rome), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), S. B. Cenko (NASA/GSFC)
Following the Fermi GBM detection (GCN 38085), we observed the transient field in J-filter with PRIME ~31 hours after Fermi GBM detection.
At the counterpart positions reported by GOTO (GCN 38088), Swift XRT (GCN 38098), and Swift UVOT(GCN 38110), we detect no uncatalogued sources in J-band. Using nearby VISTA Hemispherical Survey (VHS) stars for preliminary calibration we derive a limiting magnitude of <21.2 AB, not corrected for Galactic extinction.
PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023, Durbak et al. 2024).
We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.
GCN Circular #38123
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, Jin-Peng Zhang, Yue Wang, Hao-Xi Wang, Jin Wa= ng, Jin-Zhou Wang, Ping Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Li= n Xiong, Jian-Ying Ye, Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zh= ang, Shuang-Nan Zhang, Yan-Qiu Zhang, Yan-Ting Zhang, Shu-Min Zhao, Xiao-Yu= n Zhao (IHEP), Maria-Grazia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IR= AP), David Corre (CEA), Tais Maiolino (LUPM), Fr=C3=A9d=C3=A9ric Piron (LUP= M), St=C3=A9phane Schanne (CEA), Jingwei Wang (IAP), JeanLuc Att=C3=A9ia (I= RAP)
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= 241105A (SVOM trigger reference: sb24110502) at 2024-11-05T16:06:05.00 UT = (T0), which was also observed by Fermi/GBM (Fermi GBM Team, GCN 38085), Kon= us-Wind (D. Frederiks et al., GCN 38103), and Swift/BAT (J. DeLaunay et al.= , GCN 38108).
The real-time alert data and light curves of SVOM/GRM were downlinked to th= e ground through the VHF system with low latency. With the event-by-event d= ata downloaded through the X-band ground station, the GRM light curve shows= that this burst consists of a short single pulse with a duration of about = 2 s and a weaker extended emission with a duration of about 40 s. The signi= ficance of extended emission observed by GRD03 is about 3.6 sigma from T0+2= to T0+42 s.
The initial pulse spectrum from T0-0.5 to T0+1.7 s is best fit by a power l= aw function with an exponential high-energy cutoff. The power law index is = -0.93 +/- 0.54 and the cutoff energy, parameterized as Epeak, is 214 +/- 59= keV. The event fluence (10-1000 keV) in this time interval is (1.05 +/- 0.= 19)E-06 erg/cm^2.
The extended emission spectrum from T0+1.7 to T0+42 s is best fit by a powe= r law function. The power law index is -1.63 +/- 0.18. The event fluence (1= 0-1000 keV) in this time interval is (1.76 +/- 0.31)E-07 erg/cm^2.
The time-integrate spectrum from T0-0.5 to T0+42 s is best fit by a power l= aw function with an exponential high-energy cutoff. The power law index is = -1.23 +/- 0.52 and the cutoff energy, parameterized as Epeak, is 455 +/- 33= 5 keV. The event fluence (10-1000 keV) in this time interval is (2.13 +/- 0= .48)E-07 erg/cm^2. According to the redshift z=3D2.702 (Izzo et al., GCN 38= 097), we estimate the burst isotropic equivalent radiated energy, parameter= ized as Eiso, is (1.76 +/- 0.76)E+53 erg (1-10000 keV).
The burst position (from Swift/BAT) was outside the SVOM/ECLAIRs field of v= iew at trigger time.
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 point of contact for this burst is: Chao Zheng (zhengchao97@ihep.ac.cn)
GCN Circular #38124
H. Zhou (PMO, CAS), R.-Z. Li (YNAO, CAS), X. L. Chen, K. Chatterjee (YNU), S. Q. Jiang, T. Zhao, D. Y. Li, W. Chen, C. C. Jin, H. W. Pan (NAO,CAS), E. Troja (U Rome), X. F. Wu (PMO, CAS), P. Jonker (Radboud Univ.) report on behalf of the Einstein Probe team:
The Follow-up X-ray telescope (FXT) on board the Einstein Probe mission performed two follow-up observations of GRB 241105A (Fermi GBM team, GCN 38085; DeLaunay et al., GCN 38091; Frederiks et al., GCN 38103), and detected a fading uncataloged X-ray source. The EP-FXT loaction of the X-ray source is consistent with the location of the optical counterpart of GRB 241105A (Julakanti et al., GCN 38088; Izzo et al., GCN 38097; SVOM/VT team, GCN 38099; Hu et al., GCN 38106).
The results are reported:
```
+--------------------------------------------------------------------------------------------------------+
   T_start (UTC)    |     T_end (UTC)     | Exposure (s) | T_mid - T_0 (h) | Flux (0.5-10keV, erg/s/cm^2)
+--------------------------------------------------------------------------------------------------------+
2024-11-06T13:40:26 | 2024-11-06T14:28:44 |     2894     |       22.0      |     (1.51+/-0.31)E-13
2024-11-07T04:05:45 | 2024-11-07T08:05:40 |     7966     |       38.0      |     (3.79+/-0.50)E-14
+--------------------------------------------------------------------------------------------------------+
```
The derived temporal decay index is 2.5 +/- 0.4, which is consistent with the value reported by the Swift-XRT team (Kennea et al., GCN 38098).
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).
GCN Circular #38167
L. Izzo (INAF-OACn & DARK/NBI), A. A. Chrimes (ESA/ESTEC & Radboud Univ.), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Saccardi (CEA/Irfu), A. Martin-Carrillo (UCD), A. J. Levan (Radboud Univ. and Warwick Univ.), B. P. Gompertz (Birmingham), N. R. Tanvir (U. Leicester), J. T. Palmerio (CEA/Irfu), report on behalf of the Stargate collaboration:
Using the most updated calibration files, we have produced an improved reduction of the VLT/FORS2 afterglow spectrum (Izzo et al., GCN 38097) of GRB 241105A (Fermi GBM Team, GCN 38085; Yulakanti et al., GCN 38088). Compared to our preliminary version based on archival calibrations, we have found a slight discrepancy in the wavelength solution.
Based on the same features already discussed in our previous GCN 38097, the refined redshift we measure for GRB 241105A is z = 2.681. This change implies a modest reduction of ~1% and ~2% in the Eiso and Liso values reported by Frederiks et al. (GCN 38103) and Pathak et al. (GCN 38104).
GCN Circular #38189
G. E. Anderson (Curtin), S. Belkin (Monash), J. K. Leung (UofT/HUJI), A. J. van der Horst (GWU), L. Rhodes (TSI/McGill), A. Gulati (USyd), S. Chastain (UNM), B. Gompertz (Birmingham) on behalf of the ATCA PanRadio GRB collaboration
We observed the likely short GRB 241105A (Fermi GBM Collaboration, GCN 38085) with the Australia Telescope Compact Array (ATCA) 4.8 days post-burst on 2024-11-10 (08:30-13:30 UT). No radio source was detected at the location of the optical counterpart (Julakanti et al. GCN 38088, Izzo et al., GCN 38097; SVOM/VT team, GCN 38099; Hu et al., GCN 38106; Siegel et al., GCN 38110; Dichiara et al., GCN 38111; Rastinejad et al., GCN 38113; Tsalapatas et al., GCN 38119) at 5.5 and 9 GHz, with 3-sigma upper limits of 54 and 39 microJy/beam, 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.
GCN Circular #38302
G. E. Anderson (Curtin), S. Chastain (UNM), S. Belkin (Monash), J. K. Leung (UofT/HUJI), A. J. van der Horst (GWU), L. Rhodes (TSI/McGill), A. Gulati (USyd), B. Gompertz (Birmingham) on behalf of the PanRadio GRB collaboration
We re-observed GRB 241105A (Fermi GBM Collaboration, GCN 38085) with the Australia Telescope Compact Array (ATCA) 15 days post-burst on 2024-11-20 (11:00-19:00 UT). We detected a radio source coincident with the location of the optical counterpart (Julakanti et al. GCN 38088, Izzo et al., GCN 38097; SVOM/VT team, GCN 38099; Hu et al., GCN 38106; Siegel et al., GCN 38110; Dichiara et al., GCN 38111; Rastinejad et al., GCN 38113; Tsalapatas et al., GCN 38119) at 9 GHz with a flux density of ~100 microJy/beam (rms of 11 microJy/beam). Further observations are planned.
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.
GCN Circular #38654
Dimple (U. Birmingham), B. P. Gompertz (U. Birmingham), A. J. Levan (Radboud Univ. and Warwick Univ.), D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Martin-Carrillo (UCD), M. E. Ravasio (Radboud Univ.), L. Izzo (INAF/OACn & DARK/NBI), Andrea Rossi (INAF/OAS), P. D'Avanzo (INAF/OABr), N. R. Tanvir (U. Leicester) on behalf of a larger collaboration:
We conducted photometric observations of the GRB 241105A field (Fermi GBM team, GCN 38085; DeLaunay et al., GCN 38091; Frederiks et al., GCN 38103; Julakanti et al., GCN 38088; Izzo et al., GCN 38097; SVOM/VT team, GCN 38099; Hu et al., GCN 38106) at a redshift of z = 2.681 (Izzo et al., GCN 38167) using the James Webb Space Telescope (JWST; DDT program 9228, PI: Dimple). These observations, carried out with the NIRCam instrument in multiple bands (F070W, F115W, F150W, F277W, F356W, F444W), began on 2024-12-22 at 17:26 UT, approximately 47 days after the trigger (~12.7 days in the GRB rest frame).
The bright galaxy identified in archival images (Julakanti et al., GCN 38088) is well detected in all observed bands, and is resolved into at least two bright, extended spots about 0.2" apart. The afterglow position is within 0.06" of the NE spot centroid (about 500 pc in projection at z = 2.681). The NE patch has a magnitude of F277W(AB) = 22.54±0.03. This is significantly brighter than a SN akin to SN 1998bw at z = 2.681, which would peak at magnitude ~26.3 In the same filter, making it hard to determine the contribution from an underlying SN, should any be present. Subtraction of the galaxy's contribution, which will be possible with late-time imaging, will help to single out any transient emission.
We acknowledge the support from Weston Eck and Armin Rest (STScI) in preparing these observations.

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Jochen Greiner, last update: 23-Dec-2024 [Disclaimer]