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[vsnet-grb-info 42270] Fermi trigger No 796485221: Global MASTER-Net observations report
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44149 SUBJECT: Fermi trigger No 796485221: Global MASTER-Net observations report DATE: 26/03/29 23:31:14 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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 [1] located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB260329.58 (trigger No 796485221,19h 47m 48.00s , -55d 55m 12.0s, R=7.59) errorbox 33703 sec after notice time and 33736 sec after trigger time at 2026-03-29 23:15:52 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 69 deg. The sun altitude is -60.5 deg. The galactic latitude b = -30 deg., longitude l = 342 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3219478 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 33796 | 2026-03-29 23:15:52 | MASTER-SAAO | (19h 42m 30.66s , -55d 55m 47.3s) | C | 120 | 18.7 | 33796 | 2026-03-29 23:15:52 | MASTER-SAAO | (19h 45m 45.76s , -56d 11m 20.9s) | C | 120 | 18.7 | 33948 | 2026-03-29 23:18:24 | MASTER-SAAO | (19h 42m 36.60s , -55d 56m 48.4s) | C | 120 | 18.8 | 33948 | 2026-03-29 23:18:24 | MASTER-SAAO | (19h 45m 51.90s , -56d 12m 19.9s) | C | 120 | 18.8 | 34100 | 2026-03-29 23:20:56 | MASTER-SAAO | (19h 17m 26.52s , -55d 57m 25.2s) | C | 120 | 18.6 | 34100 | 2026-03-29 23:20:56 | MASTER-SAAO | (19h 20m 42.35s , -56d 12m 54.8s) | C | 120 | 18.9 | 34252 | 2026-03-29 23:23:28 | MASTER-SAAO | (19h 17m 32.63s , -55d 57m 06.4s) | C | 120 | 18.6 | 34252 | 2026-03-29 23:23:28 | MASTER-SAAO | (19h 20m 48.48s , -56d 12m 34.7s) | C | 120 | 18.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/44149. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42269] GRB 260327A: Insight-HXMT/HE detection
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44148 SUBJECT: GRB 260327A: Insight-HXMT/HE detection DATE: 26/03/29 15:18:30 GMT FROM: xueyuan zao <zaoxueyuan(a)gmail.com> Xue-Yuan Zao, Chen-Wei Wang, Cheng-Kui Li, Shao-Lin Xiong, and Chao Zheng (IHEP) report on behalf of the Insight-HXMT team: At 2026-03-27T02:28:50.350 (T0), Insight-HXMT/HE detected a long burst, GRB 260327A, which is also detected by AstroSat CZTI (A. Arya et. al., GCN #44130) and Konus-Wind (IPN notice). The Insight-HXMT/HE light curve mainly consists of two emission episodes with a total duration (T90) of 98 +14/-6 s. The 1s peak rate, measured from T0-1 s, is 2435 cnts/sec. Insight-HXMT/HE detected a total of 22378 counts from this burst. The Insight-HXMT /HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb260327A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://hxmten.ihep.ac.cn/ View this GCN Circular online at https://gcn.nasa.gov/circulars/44148. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42268] EP260329b: Optical follow-up with Kinder observations
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44147 SUBJECT: EP260329b: Optical follow-up with Kinder observations DATE: 26/03/29 14:47:29 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> A. Aryan, A. Sankar.K, T.-W. Chen, C.-S. Lin (all NCU), A. K. H. Kong (NTHU), S. J. Smartt, J. Gillanders (both Oxford), M. Nicholl (QUB), M.-H. Lee, A. Dutta, Y.-H. Lee, Y.-C. Pan, C.-C. Ngeow, C.-H. Lai, H.-C. Lin, W.-J. Hou, H.-Y. Hsiao, J.-K. Guo (all NCU), S. Yang, Z. N. Wang, D. C. Qiang, L. L. Fan (all HNAS), Y. J. Yang (NYUAD), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford), M. Fulton, K. W. Smith, C. Angus, A. Aamer (all QUB), T. Moore (STScI), A. Schultz and M. Huber (both IfA, Hawaii) report: We observed the field of the fast X-ray transient EP260329b (Song et al., GCN 44142) using the 1m LOT at the Lulin observatory, as part of the Kinder collaboration (Chen et al. 2025, ApJ, 983, 86, doi:10.3847/1538-4357/adb428). The first LOT epoch of observations in r-band started at 12:01 UTC on 29th of March 2026 (MJD 61128.501), 1.42 hr after the EP-WXT detection. We utilized the astroalign (Beroiz et al. 2020, A&C, 32, 100384) and astropy (Astropy Collaboration et al. 2022, ApJ, 935, 167) packages to align and stack the individual frames. Our images were strongly affected by moonlight, and are therefore relatively shallow. In the stacked r-band image at t_mid - t_0 =1.80 hr, we did detect a very faint source (SNR 3.4) at the reported position of the optical counterpart candidate (Wenxiong et al., GCN 44139; Zhu et al., GCN 44140; and Eyles-Ferris et al., GCN 44144). Moreover, we further used AutoPhOT to perform PSF photometry. The details of the observations and measured photometry/the 3-sigma upper limit (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 (hr) | Exposure (s) | Magnitude | avg. Seeing | Med. Airmass LOT | r | 61128.501 | 1.42 | 300 * 8 | 20.19+/-0.14 |1".71 | 1.54 LOT | g | 61128.536 | 2.26 | 300 * 7 | >19.9 |1".50 | 1.34 Our observations confirm the rapidly fading nature of the optical counterpart candidate. The presented magnitudes are calibrated using the field stars from ATLAS-RefCat2 catalog from MAST (Tonry J. L. et al. 2018, ApJ, 867, 105). The reported magnitudes are not corrected for an expected galactic extinction of A_g = 0.06 mag and A_r = 0.04, in the direction of the transient (Schlafly & Finkbeiner 2011). The methodology, details on the Lulin observatory telescopes, and a compilation of our optical follow-up campaign for FXTs discovered within the first year of operation of the Einstein-Probe mission are presented in Aryan et al. 2025, ApJS, 281, 20, doi:10.3847/1538-4365/adfc69. View this GCN Circular online at https://gcn.nasa.gov/circulars/44147. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42267] EP 260329b: COLIBRÍ optical observations
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44146 SUBJECT: EP 260329b: COLIBRÍ optical observations DATE: 26/03/29 14:45:02 GMT FROM: Francesco at Aix-Marseille Université, CPPM/CNRS <francesco.magnani.work(a)gmail.com> Francesco Magnani (CPPM), Noémie Globus (UNAM), Rosa L. Becerra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM) and Antonio de Ugarte Postigo (LAM) report: We imaged the field of EP 260329b (Song et al., GCN Circ. 44142) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-03-29 11:21 to 11:41 UTC (from 45.7 to 65.0 minutes after the trigger) and obtained 16 minutes of exposure in the r and z filters, respectively. The data were reduced and coadded with the COLIBRÍ pipeline and analysed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. We detected the optical counterpart reported by LCO (Li et al., GCN Circ. 44139, Eyles-Ferris et al., GCN Circ. 44144) and TRT (Zhu et al., GCN Circ 44140), at preliminary magnitudes of: r = 18.85 +/- 0.08 z = 18.53 +/- 0.13 Further observations are planned. We thank the staff of the Observatorio Astronómico Nacional at Sierra de San Pedro Mártir, as well as the technical and engineering teams at CEA, CPPM, IRAP, LAM, OHP, OSU Pytheas, and UNAM. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/44146. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42266] EP260329a: Optical upper limit with Kinder observations
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44145 SUBJECT: EP260329a: Optical upper limit with Kinder observations DATE: 26/03/29 14:40:17 GMT FROM: Janet Chen at National Central University <janetstars(a)gmail.com> A. Sankar.K, A. Aryan, T.-W. Chen, C.-S. Lin (all NCU), S. Yang (HNAS), A. K. H. Kong (NTHU), S. J. Smartt, J. Gillanders (both Oxford), M. Nicholl (QUB), M.-H. Lee, A. Dutta, Y.-H. Lee, Y.-C. Pan, C.-C. Ngeow, C.-H. Lai, H.-C. Lin, W.-J. Hou, H.-Y. Hsiao, J.-K. Guo (all NCU), Y. J. Yang (NYUAD), Z. N. Wang, D. C. Qiang, L. L. Fan (all HNAS), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford), M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz M. Huber, K. Chambers (all IfA, Hawaii) report: We observed the field of the EP260329a (Yang et al., GCN 44141) using the 40cm SLT at the Lulin observatory, as part of the Kinder collaboration (Chen et al. 2025, ApJ, 983, 86, doi:10.3847/1538-4357/adb428). The first SLT epoch of observations in g-band started at 11:03 UTC on 29th of March 2026 (MJD 61128.460), 7.54 hr after the EP-WXT detection. We utilized the astroalign (Beroiz et al. 2020, A&C, 32, 100384) and astropy (Astropy Collaboration et al. 2022, ApJ, 935, 167) packages to align and stack the individual frames. We used the Python-based AutoPhOT package (Brennan & Fraser, 2022, A&A, 667, A62) to perform template subtraction of the Pan-STARRS1 3Pi archive image (Chambers et al., 2016, arXiv:1612.05560) using the 'SFFT' (Hu et al., 2022, ApJ, 936, 157) algorithm. Neither in the stacked nor in the difference image did we detect any signature of a new or uncatalogued source within the EP-WXT localization circle (3.2'). Moreover, we further used AutoPhOT to perform PSF photometry. The details of the observations and the 3-sigma upper limit (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 (hr) | Exposure (s) | Magnitude| avg. Seeing | Med. Airmass SLT | r | 61128.460 | 7.54 | 300 * 9 | >21.1 | 2".36 | 3.02 The presented magnitudes are calibrated using the field stars from the PanSTARRS catalog. The reported upper limit is not corrected for an expected galactic extinction of A_r = 0.44 mag in the direction of the transient (Schlafly & Finkbeiner 2011). The methodology, details on the Lulin observatory telescopes, and a compilation of our optical follow-up campaign for FXTs discovered within the first year of operation of the Einstein-Probe mission are presented in Aryan et al. 2025, ApJS, 281, 20, doi:10.3847/1538-4365/adfc69. View this GCN Circular online at https://gcn.nasa.gov/circulars/44145. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42265] EP260329b: LCO optical observations of the counterpart
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44144 SUBJECT: EP260329b: LCO optical observations of the counterpart DATE: 26/03/29 13:42:38 GMT FROM: Rob Eyles-Ferris at U of Leicester <raje1(a)leicester.ac.uk> R. A. J. Eyles-Ferris (Leicester), A. van Hoof (Radboud), G. Corcoran (UCD), J. Chácon (PUC), A. Martin-Carrillo (UCD), J. Quirola-Vasquez (Radboud), A. J. Levan (Radboud), F. E. Bauer (SSI and UTA) and P. G. Jonker (Radboud) report on behalf of a larger collaboration: We observed the field of the fast X-ray transient EP260329b (Song et al., GCN 44142) with LCO 1m telescopes located at the Siding Spring Observatory (Australia) equipped with the SINISTRO instrument. We obtained 6 x 300 exposures in each of the r and z filters, starting from 2026-03-29 12:03:17 UT (t_mid = 1.74 hr and 1.78 hr post trigger respectively). We clearly detect the optical counterpart reported by Li et al. (GCN 44139) and Zhu et al. (GCN 44140) in our stacked images and measure the following AB magnitudes calibrated to Pan-STARRS and not corrected for Galactic extinction: r = 19.84 +/- 0.05 z = 19.38 +/- 0.05 Our measurements are >1 magnitude fainter than those reported by Li et al. (GCN 44139) and Zhu et al. (GCN 44140) indicating the counterpart is fading rapidly. View this GCN Circular online at https://gcn.nasa.gov/circulars/44144. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42264] GRB 260326A: Insight-HXMT/HE detection
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44143 SUBJECT: GRB 260326A: Insight-HXMT/HE detection DATE: 26/03/29 12:55:38 GMT FROM: Xinghao Luo at IHEP <2952704891(a)qq.com> Xing-Hao Luo, Chen-Wei Wang, Chao Zheng, Cheng-Kui Li and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team: At 2026-03-26T01:18:33.250 (T0), Insight-HXMT/HE detected the burst GRB 260326A, which is also detected by Fermi/GBM (Fermi GBM team, GCN #44115). The Insight-HXMT/HE light curve mainly consists of multiple pulses with a T90 of 15 +1/-0.5 s. The 1s peak rate, measured from T0+0.75 s, is 6592 cnts/sec. Insight-HXMT/HE detected a total of 39437 counts from this burst. The HXMT/HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb260326A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://hxmten.ihep.ac.cn/ View this GCN Circular online at https://gcn.nasa.gov/circulars/44143. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42263] EP260329b: Einstein Probe detection of an X-ray transient
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44142 SUBJECT: EP260329b: Einstein Probe detection of an X-ray transient DATE: 26/03/29 12:07:29 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> F.-F Song (YNAO, CAS), Guojiong Yang, Wei Chen, Yuan Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260329b. The transient triggered EP-WXT (ID: 01709259209) at 2026-03-29T10:36:00 (UTC). The WXT position of the source is R.A. = 181.309 deg, DEC = 4.362 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic). A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 181.3122 deg, DEC = 4.3526 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic). Further information will be updated when the telemetry data is received. 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). View this GCN Circular online at https://gcn.nasa.gov/circulars/44142. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42262] EP260329a: Einstein Probe detection of an X-ray transient
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44141 SUBJECT: EP260329a: Einstein Probe detection of an X-ray transient DATE: 26/03/29 11:35:22 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Guojiong Yang (NAO, CAS), F.-F Song(YNAO, CAS), Wei Chen, Yuan Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260329a. The transient triggered EP-WXT (ID: 01709259198) at 2026-03-29T03:30:40 (UTC). The WXT position of the source is R.A. = 5.459 deg, DEC = 82.513 deg (J2000) with an uncertainty of 3.2 arcmin in radius (90% C.L. statistical and systematic). The WXT 0.5-4 keV spectrum can be described by an absorbed power law. Since the hydrogen column density is not well constrained by the current data, it was fixed at the Galactic value 0.1 x 10^22 cm^-2. The best-fit photon index is 2.23 (-0.69/+2.26). The derived 0.5-4 keV flux is 1.43 (-0.33/+0.40) x 10^-10 erg cm^-2 s^-1. A follow-up observation with the Follow-up X-ray Telescope (FXT) is scheduled. Further information will be updated when the telemetry data is received. 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). View this GCN Circular online at https://gcn.nasa.gov/circulars/44141. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42261] EP-WXT trigger 01709259209: TRT optical counterpart detection
by GCN Circulars 29 Mar '26

29 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44140 SUBJECT: EP-WXT trigger 01709259209: TRT optical counterpart detection DATE: 26/03/29 11:32:38 GMT FROM: Zipei Zhu at NAOC <zpzhu(a)nao.cas.cn> Z.P. Zhu (NAOC), S. Tinyanont, K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), J. An, X. Liu, S.Q. Jiang, L.B. He, N.C. Sun, W.X. Li, D. Xu (NAOC), S.Y. Fu (HUST) report on behalf of a large collaboration: We observed the field of EP260329a detected by the Einstein Probe (EP) (Trigger ID: 01709259209 ), using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at Sierra Remote Observatories in California. We obtained several exposure frames in the R filter. The optical counterpart located at: R.A. (J2000) = 12:05:14.95 () Dec.( J2000) = +4:21:05.8 with an uncertainty of ~ 0.8 arcsec. The uncatalogued source is clearly detected in the stacked image with the measured brightness of R = 18.4 +/- 0.1 at a mid-time of 10:47:20 UTC on 2026-03-29., consistant with the optical candidate reported by LCO (Li et al., GCN 44139), calibrated using nearby stars from the Pan-STARRS catalog and are not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44140. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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