Gamma-ray Burst 240102A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:46:15 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.828d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 11"} (J2000)
POINT_ROLL:      188.061d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63430.61 SOD {17:37:10.61} UT,   76291.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.008
N_STARS:         167
X_OFFSET:        531 [pixels]
Y_OFFSET:        399 [pixels]
X_MAX:           1490 [pixels]
Y_MAX:           1358 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01205899000msufc76291.fits
SUN_POSTN:       282.84d {+18h 51m 23s}  -22.91d {-22d 54' 35"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.64d {+11h 50m 33s}   +3.27d {+03d 16' 16"}
MOON_DIST:        82.27 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:46:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.828d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 11"} (J2000)
POINT_ROLL:      188.061d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63430.61 SOD {17:37:10.61} UT,   76291.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.008
N_STARS:         167
X_OFFSET:        531 [pixels]
Y_OFFSET:        399 [pixels]
X_MAX:           1490 [pixels]
Y_MAX:           1358 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw01205899000msufc76291.fits
SUN_POSTN:       282.85d {+18h 51m 23s}  -22.91d {-22d 54' 35"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.64d {+11h 50m 33s}   +3.27d {+03d 16' 14"}
MOON_DIST:        82.27 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:47:43 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.828d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 11"} (J2000)
ROLL:            188.061d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63430.61 SOD {17:37:10.61} UT,   76291.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     725909863
X_OFFSET:        851 [pixels]
Y_OFFSET:        719 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       879
BINNING_INDEX:   1
IM_URL:          sw01205899000msuni76324.fits
SUN_POSTN:       282.85d {+18h 51m 23s}  -22.91d {-22d 54' 35"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.65d {+11h 50m 35s}   +3.27d {+03d 15' 56"}
MOON_DIST:        82.28 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:47:56 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.828d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 11"} (J2000)
ROLL:            188.061d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63430.61 SOD {17:37:10.61} UT,   76291.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     725909863
X_OFFSET:        851 [pixels]
Y_OFFSET:        719 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       879
BINNING_INDEX:   1
IM_URL:          sw01205899000msuni76324.fits
SUN_POSTN:       282.85d {+18h 51m 23s}  -22.91d {-22d 54' 35"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.65d {+11h 50m 36s}   +3.26d {+03d 15' 53"}
MOON_DIST:        82.28 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:49:54 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.829d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 10"} (J2000)
POINT_ROLL:      188.062d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63589.18 SOD {17:39:49.18} UT,   76449.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.626
N_STARS:         148
X_OFFSET:        531 [pixels]
Y_OFFSET:        399 [pixels]
X_MAX:           1490 [pixels]
Y_MAX:           1358 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01205899000msufc76449.fits
SUN_POSTN:       282.85d {+18h 51m 23s}  -22.91d {-22d 54' 35"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.66d {+11h 50m 39s}   +3.26d {+03d 15' 26"}
MOON_DIST:        82.29 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:50:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.829d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 10"} (J2000)
POINT_ROLL:      188.062d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63589.18 SOD {17:39:49.18} UT,   76449.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.626
N_STARS:         148
X_OFFSET:        531 [pixels]
Y_OFFSET:        399 [pixels]
X_MAX:           1490 [pixels]
Y_MAX:           1358 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01205899000msufc76449.fits
SUN_POSTN:       282.85d {+18h 51m 23s}  -22.91d {-22d 54' 34"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.66d {+11h 50m 40s}   +3.26d {+03d 15' 22"}
MOON_DIST:        82.29 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:51:21 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.829d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 10"} (J2000)
ROLL:            188.062d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63589.18 SOD {17:39:49.18} UT,   76449.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     725910021
X_OFFSET:        851 [pixels]
Y_OFFSET:        719 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       879
BINNING_INDEX:   1
IM_URL:          sw01205899000msuni76482.fits
SUN_POSTN:       282.85d {+18h 51m 24s}  -22.91d {-22d 54' 34"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.67d {+11h 50m 42s}   +3.25d {+03d 15' 06"}
MOON_DIST:        82.30 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 02 Jan 24 17:51:38 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1205899,   Seg_Num: 0
POINT_RA:         96.829d {+06h 27m 19s} (J2000)
POINT_DEC:       -20.020d {-20d 01' 10"} (J2000)
ROLL:            188.062d
IMG_START_DATE:  20311 TJD;     2 DOY;   24/01/02
IMG_START_TIME:  63589.18 SOD {17:39:49.18} UT,   76449.8 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     725910021
X_OFFSET:        851 [pixels]
Y_OFFSET:        719 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1011
Y_GRB_POS:       879
BINNING_INDEX:   1
IM_URL:          sw01205899000msuni76482.fits
SUN_POSTN:       282.85d {+18h 51m 24s}  -22.91d {-22d 54' 34"}
SUN_DIST:        136.69 [deg]   Sun_angle= -11.6 [hr] (East of Sun)
MOON_POSTN:      177.68d {+11h 50m 42s}   +3.25d {+03d 15' 02"}
MOON_DIST:        82.30 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      228.46,-14.12 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       98.82,-43.25 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #35461
J.D. Gropp (PSU), S. Dichiara (PSU), J. A. Kennea (PSU), K. L. Page (U Leicester) and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 17:34:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 240102A (trigger=1205899). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 96.846, -20.024 which is
```
   RA(J2000) = 06h 27m 23.0s
   Dec(J2000) = -20d 01' 26.4"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). We currently have no information regarding the BAT light-curve.
The XRT began observing the field at 17:37:00.6 UT, 125 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 96.83800, -20.04076 which is equivalent to:
```
   RA(J2000)  = 06h 27m 21.12s
   Dec(J2000) = -20d 02' 26.7"
```
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This position is 66 arc-seconds from the BAT localization. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.34 x 10^21 cm^-2 (Willingale et al. 2013).
No afterglow is detected in the initial UVOT data products.
Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular #35465
Y.-D. Hu, E. Fernandez-Garcia, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland) and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report:
Following the detection of GRB 240102A by Swift (Gropp et al. GCNC 35461), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) observed the GRB location starting on Jan. 2, 18:41 UT (~ 1.1 hours after trigger) in different optical bands. No new optical source is detected on the co-added images (2 x 60 s, clear-filter) within the Swift/XRT error box down to 20.2 mag. Further imaging is ongoing.
We thank the staff at Boyden Observatory for their excellent support.
GCN Circular #35467
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:
We observed the Swift GRB 240102A (Gropp et al., GCN 35461) field with the LCOGT 1-meter Sinistro instrument at the Teide Observatory, Tenerife site, on January 2, from 23:34 to January 3 00:07 UT (corresponding to 6.00 to 6.55 hours after the GRB trigger time) with the sdss r and i filters.
We performed a series of 3x300s exposures in each band. We do not detect an uncatalogued source within the XRT error region in either band. This result is consistent with other optical upper limits (Hu et al., GCN 35465).
The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference:
```
r > 22.9
i > 22.3
```
These magnitudes are not corrected for galactic extinction.
GCN Circular #35469
J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.6 ks of XRT data for GRB 240102A, from 113 s to 28.3 ks after the BAT trigger. The data comprise 91 s in Windowed Timing (WT) mode (the first 10 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The best available XRT position (using the promptly downlinked event data, the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 96.83800, -20.04076 which is equivalent to:
```
RA (J2000): 06 27 21.12
Dec(J2000): -20 02 26.7
```
with an uncertainty of 1.9 arcsec (radius, 90% confidence).
The late-time light curve (from T0+4.7 ks) can be modelled with a power-law decay with a decay index of alpha=0.5 (+/-0.3).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.74 (+0.11, -0.10). The best-fitting absorption column is 3.3 (+0.6, -0.5) x 10^21 cm^-2, in excess of the Galactic value of 2.3 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.3 x 10^-11 (5.7 x 10^-11) erg cm^-2 count^-1.
A summary of the WT-mode spectrum is thus:
```
Total column:	     3.3 (+0.6, -0.5) x 10^21 cm^-2
Galactic foreground: 2.3 x 10^21 cm^-2
Excess significance: 3.1 sigma
Photon index:	     1.74 (+0.11, -0.10)
```
If the light curve continues to decay with a power-law decay index of 0.5, the count rate at T+24 hours will be 9.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.2 x 10^-13 (5.6 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01205899.
This circular is an official product of the Swift-XRT team.
GCN Circular #35471
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 4654 s of XRT Photon Counting mode data and 7 UVOT images for GRB 240102A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 96.83931, -20.04096 which is equivalent to:
```
RA (J2000): 06h 27m 21.43s
Dec (J2000): -20d 02' 27.5"
```
with an uncertainty of 2.2 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN Circular #35475
A. Belles (PSU) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240102A 113 s after the BAT trigger (Gropp et al., GCN Circ. 35461). No optical afterglow consistent with the XRT position (Goad et al., GCN Circ. 35471) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           135          285          147         >20.7
u_FC               294          544          246         >19.9
white              135         1196          353         >21.1
v                  113         1246           90         >18.8
b                  550         1172           58         >19.5
u                  294         1314          299         >20.0
w1                 676         1295           78         >19.0
m2                 823         1270           58         >18.7
w2                 600         1221           78         >19.3
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.176 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #35476
M. J. Moss (GSFC), S. D. Barthelmy (GSFC), J.D. Gropp (PSU), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240102A (trigger #1205899) (Gropp et al., GCN Circ. 35461). The BAT ground-calculated position is RA, Dec = 96.848, -20.011 deg which is
```
   RA(J2000)  =  06h 27m 23.5s
   Dec(J2000) = -20d 00' 39.0"
```
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve show some weak emission that starts at ~T+8 s and ends at ~T+140 s. T90 (15-350 keV) is 119.00 +- 30.59 sec (estimated error including systematics).
The time-averaged spectrum from T+8.00 to T+142.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.00 +- 0.22. The fluence in the 15-150 keV band is 8.5 +- 1.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+65.00 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1205899/BA/
GCN Circular #35484
Amit K. Ror, Rahul Gupta, Amar Aryan, and Shashi B. Pandey (ARIES) report:
We observed the field of GRB 240102A detected by Swift (Gropp et al. 2024, GCN 35461) 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 2024-01-02 at 18:23:56 UT, i.e., ~ 49 minutes after the BAT trigger. We have taken multiple frames with an exposure time of 300 s in the R filter. We stacked the images after the alignment. We did not detect any optical afterglow in our stacked image within the enhanced Swift-XRT error box (Goad et al., 2024, GCN 35471). We obtain the following preliminary 3-sigma upper limit in the stacked image:
```
Date Start_UT T_start-T0 (minutes) Filter  Exp time (s)  Limiting magnitude
=========================================================
2024-01-02 18:23:56    ~49     R     300*20     > 21.5
```
Our non-detection is consistent with the observations of Hu et al. 2024, GCN 35465; Strausbaugh et al. 2024, GCN 35467; and Belles et al. 2024, GCN 35475.
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.

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Jochen Greiner, last update: 05-Jan-2024 [Disclaimer]