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[vsnet-grb-info 42145] EP260314a: optical upper limit with Kinder observations
by GCN Circulars 16 Mar '26

16 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44024 SUBJECT: EP260314a: optical upper limit with Kinder observations DATE: 26/03/16 10:31:28 GMT FROM: Amar Aryan at National Central University, Institute of Astronomy (NCUIA) <amararyan941(a)gmail.com> C.-H. Lai, A. Aryan, Y.-H. Lee, C.-S. Lin, T.-W. Chen (all NCU), A. K. H. Kong (NTHU), J. H. Gillanders, S. J. Smartt (both Oxford), Y. J. Yang (NYUAD), A. Sankar.K, M.-H. Lee, Y.-C. Pan, C.-C. Ngeow, W.-J. Hou, H.-Y. Hsiao, H.-C. Lin, J.-K. Guo (all NCU), S. Yang, Z. N. Wang, L. L. Fan, G. H. Sun (all HNAS), H.-W. Lin (UMich), H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford), M. Nicholl, M. Fulton, T. Moore, K. W. Smith, C. Angus, A. Aamer (all QUB), A. Schultz, and M. Huber (both IfA, Hawaii) report: We observed the field of the EP260314a (Zhao et al., GCN 44010; Wu et al., GCN 44016) 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 g-band started at 16:09 UTC on 15th of March 2026 (MJD 61114.673), 17.52 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 utilized the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform template subtraction with the DESI Legacy Survey (Dey et al. 2019, AJ 157, 168) DR10 image 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 the optical counterpart candidate reported by Li et al., (GCN 44013). 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 LOT | r | 61114.673 | 17.52 | 300 * 6 | >22.8 | 1".31 | 1.81 Our upper limit is consistent with previously reported non-detections (Lipunov et al., GCN 44014; Pérez-García et al., GCN 44015; Fortin et al., GCN 44019). The presented magnitudes are calibrated using the field stars from the ATLAS-refcat2 catalog from MAST (Tonry J. L. et al. 2018, ApJ, 867, 105). The reported upper limit is not corrected for an expected galactic extinction of A_r = 0.16 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/44024. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42144] IceCube Alert-260315A/AT2026fpm Automatic MASTER optical blue counterpart candidate
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44023 SUBJECT: IceCube Alert-260315A/AT2026fpm Automatic MASTER optical blue counterpart candidate DATE: 26/03/15 18:39:46 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> M.J. Segura, C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), Ya.Kechin, V.Lipunov (Lomonosov MSU), N.Budnev, O.Gress (ISU), A.Kuznetsov, I.Panchenko, P.Balanutsa, G.Antipov, E.Gorbovskoy, N.Tiurina, V.Senik, A.Chasovnikov, M.Shilova,V.Topolev, D.Vlasenko, A.Sankovich, Yu.Tselik (Lomonosov MSU), D.Svinkin (Ioffe Institute), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), 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, J.Tanori, L. Villalobos, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) MASTER OT J114437.99-023613.5/AT 2026fpm discovery MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the IceCube Alert 260315A (trigger No 46886533,11h 42m 40.32s , -01d 53m 06.0s, R=0.71) errorbox 105 sec after notice time and 224 sec after trigger time at 2026-03-15 02:22:50 UT, with upper limit up to 20.4 mag. The observations began at zenith distance = 45 deg. The sun altitude is -42.8 deg. The galactic latitude b = 57 deg., longitude l = 272 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3187113 MASTER-OAFA auto-detection system [4] discovered OT source at (RA, Dec) = 11h 44m 37.99s -02d 36m 13.5s on 2026-03-15.10943 UT very close to center of neutrino errorbox (GCN Circular #44017). The OT magnitude in 'CLEAR' filter is 19.2m (mlim = 20.0). The OT is seen in 44 images. There is no minor planet at this place. We have reference image on 2026-02-12.28608 UT with 'FAULT' filter 19.9m. Spectral observations are required. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/114437.99-023613.5.png [1] Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L [2] Lipunov et al. 2022, Universe, Vol. 8(5), id.271 [3] Lipunov et a. 2019, ARep, vol.63, 293 [4] Lipunov et al. 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics,Lomonosov MSU PRESS, 591pp. http://www.pereplet.ru/lipunov/625.html#625 View this GCN Circular online at https://gcn.nasa.gov/circulars/44023. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42143] GRB 260310A / AT2026fgk: 1.3m DFOT optical observations
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44022 SUBJECT: GRB 260310A / AT2026fgk: 1.3m DFOT optical observations DATE: 26/03/15 17:21:19 GMT FROM: pawarpankaj1492(a)gmail.com Pankaj Pawar, Debalina Kar, Anshika Gupta, Dhruv Jain and Kuntal Misra (ARIES) report: We observed the likely optical counterpart of GRB 260310A, detected by Fermi/GBM(Fermi/GBM team, GCN 43951) and AstroSat(Salunke et al., GCN 43958), 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 began on 2026-03-14 at 18:29:38 UT, approximately 109.54 hours (~4.56 days) after the trigger. The reported optical couterpart AT2026fgk (Lipunov et al., GCN 43954; Konno et al., GCN 43974, Hinds et al., GCN 43977; Lipunov et al., GCN 43978; Martin-Carrillo et al., GCN 43979, Moren Méndez et al., GCN 43980; de Ugarte Postigo et al., GCN 43984, Pursiainen et al., Becerra et al., GCN 43991; Martin-Carrillo et al., GCN 44000; Watson et al., GCN 44001; Lai et al., GCN 44002; L. Izzo, GCN 44003; Brivio et al., GCN 44004; Rhodes et al., GCN 44005; Moskvitin et al., GCN 44006; Brosio et al., GCN 44021) is clearly detected in a single 100s R-band frame. We derive the following magnitude from the stacked image: Date Start_UT T_start-T0(days) Filter Exp time (s) Magnitude =============================================================== 2026-03-14 18:29:38 ~4.56 R 100s*1 18.54 ± 0.12 The reported magnitude is calibrated using Pan-STARRS field stars and is not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44022. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42142] GRB 260310A / AT2026fgk: ABObservatory and NOCTIS optical observations
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44021 SUBJECT: GRB 260310A / AT2026fgk: ABObservatory and NOCTIS optical observations DATE: 26/03/15 16:12:58 GMT FROM: A. Brosio at ABObservatory Rosarno <antonino.brosio(a)gmail.com> A. Brosio (ABObservatory Rosarno), M. A. Tripodi (ABObservatory Rosarno), S. Savaglio (Università della Calabria), S. Benatti, M. G. Guarcello (INAF - Osservatorio Astronomico di Palermo), M. Basilicata, L. Cabona, M. Rainer, F. M. Zerbi (INAF - Osservatorio Astronomico di Brera), G. Bracco, P. Cianfarra, L. Sangaletti, S. Tosi, S. Zappatore (Università di Genova), A. Di Dato (INAF - Osservatorio Astronomico di Capodimonte), D. Liguori (Osservatorio "G. Galilei", Liceo Scientifico Cariati), S. Masiero, A. Nastasi (GAL Hassin, Isnello), R. Nesci (Associazione Astronomica Antares APS di Foligno), L. Betti, E. Pace, R. Stanga (Università di Firenze), D. Ricci (INAF - Osservatorio Astronomico di Padova) for the NOCTIS team report We observed the transient AT 2026fgk, proposed as the likely optical counterpart of GRB 260310A (Konno et al., GCN 43974; Hamburg & Meegan,GCN 43975). Observations were carried out on 2026-03-14.80913 UT with the 0.30-m f/4 telescope at ABObservatory in clear band The obtained photometry is: 2026-03-14.80913 UT JD 2461114.30913 m_CV = 18.50 +/- 0.04 mag The measurement was calibrated against two APASS catalog stars,selected using Aladin. The reported magnitude is in the CV system. This measurement confirms that the optical counterpart is still clearly detected about 4.6 days after the GRB trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/44021. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42141] GRB 260310A / AT 2026fgk: iTelescope optical observations
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44020 SUBJECT: GRB 260310A / AT 2026fgk: iTelescope optical observations DATE: 26/03/15 15:06:06 GMT FROM: Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997(a)gmail.com> I observed the field of GRB 260310A = AT 2026fgk (Fermi GBM Team, GCN Circ. #43951) remotely using iTelescope.Net T21 (0.43-m f/6.8 reflector + CCD + f/4.5 focal reducer) in Utah Desert Remote Observatory at Great Basin Desert, Beryl Junction, Utah, USA. Six images with exposures of 300 sec. and Rc filter were obtained on 2026-03-15 from 08:56:17 UT (5.166 d. after the trigger) to 09:32:41 UT (5.191 d. after the trigger). I detected the optical afterglow and measured its magnitude (compared to Rc magnitudes of nearby stars from the ATLAS star catalog: Tonry et al., 2018) in the stacked image = 18.0 +/- 0.1 Rc. Magnitude is not corrected for Galactic extinction. The magnitude may be affected by contamination from the host galaxy. Stacked image: https://www.flickr.com/photos/filipp-romanov/55149149955/ F. D. Romanov (AAVSO). View this GCN Circular online at https://gcn.nasa.gov/circulars/44020. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42140] EP260314a: COLIBRÍ optical upper limit
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44019 SUBJECT: EP260314a: COLIBRÍ optical upper limit DATE: 26/03/15 12:33:39 GMT FROM: F. Fortin at IRAP <ffortin.sci.edu(a)gmail.com> Francis Fortin (IRAP), Edilberto Aguilar-Ruiz (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Missimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), 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 EP260314a (Zhao et al., GCN Circ. 44010, Wu et al., GCN Circ. 44016) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-03-15 04:49:56 to 11:14:09 UTC (from 9.1 to 12.4 hours after the trigger) and obtained 144 minutes of simultaneous exposure in the i and z filters. The data were reduced and coadded with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. In the stacked image, we do not detect the SVOM/VT optical counterpart candidate reported by Li et al., GCN Circ. 44013 down to the following 3-sigma limit: i > 24.08 z > 23.17 While a direct comparison of magnitudes between the i, z filters and the VT filters is not possible, we suggest that our limits may be consistent with a fading of the VT optical candidate, which would strengthen the hypothesis that it is the true counterpart of EP260314A. 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/44019. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42139] GRID detection of GRB 260312B
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44018 SUBJECT: GRID detection of GRB 260312B DATE: 26/03/15 11:40:03 GMT FROM: GRID Student Team at Tsinghua University <grid(a)tsinghua.edu.cn> Fanqing Zhou, Longhao Li, Chenyu Wang report on behalf of the GRID Collaboration: GRID-11B reports the detection of the long-duration GRB 260312B, which was also detected by Fermi GBM (GCN Circular 43969), MASTER-Kislovodsk (GCN Circular 43973), BALROG (GCN Circular 43970), Glowbug (GCN Circular 43976), AstroSat CZTI (GCN Circular 43989). The event was triggered with GRID on 2026-03-12 at 09:46:46 UTC. The measured burst duration (T90) in the 30-2000 keV range is approximately 11.8+/-2.3 seconds. The GRID light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB260312B/GRID_260…. GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4. View this GCN Circular online at https://gcn.nasa.gov/circulars/44018. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42138] IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44017 SUBJECT: IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 26/03/15 11:21:27 GMT FROM: A. Zegarelli at Ruhr University Bochum <azegarelli(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 26-03-15 at 02:19:06.60 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_BRONZE alert stream. The average astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 3.3512 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/142272_46886533.amon) more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 26-03-15 Time: 02:19:06.60 UT RA: 175.69 (+0.49/-0.46 deg 90% PSF containment) J2000 Dec: -1.90 (+0.53/-0.51 deg 90% PSF containment) J2000 As announced in GCN Circular 43419 (https://gcn.nasa.gov/circulars/43419) IceCube alert notices for high-energy track alerts are now also streamed via Kafka. IceCube Gold/Bronze track alerts are available on the Kafka topic 'gcn.notices.icecube.gold_bronze_track_alerts'. The probability distribution of the true neutrino direction, allowing the extraction of precise 90% containment regions around the best-fit direction, is now available for revised reconstruction of high-energy track alerts. The corresponding sky map is distributed as a FITS file and follows the explicit naming convention IceCube-YYMMDDX, where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link is provided through the GCN schema distributed via Kafka. Detailed documentation describing the alert distribution, schemas, and probability maps is available at: https://gcn.nasa.gov/missions/icecube. No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of this event. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu View this GCN Circular online at https://gcn.nasa.gov/circulars/44017. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42137] EP260314a: refined analysis of the EP-WXT and EP-FXT observations
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44016 SUBJECT: EP260314a: refined analysis of the EP-WXT and EP-FXT observations DATE: 26/03/15 09:29:55 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Yue Wu (NJU), Rui-Zhi Li (YNAO, CAS), Yaqi Zhao (USTC, PRIC) and Hai-Wu Pan (NAOC) on behalf of the Einstein Probe (EP) team: The fast X-ray transient EP260314a was detected by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission (Zhao et al., GCN 44010). The transient was detected immediately when WXT observation started at T0=2026-03-14T22:51:20. The WXT observation lasted for approximately 16 seconds, and was interrupted due to the autonomous follow-up observation. The average WXT 0.5-4 keV spectrum can be fitted with an absorbed power law with a hydrogen column density of 0.54（-0.27/+0.32）×10^22 cm^-2 and a photon index of 1.81(-0.75/+0.83). The derived average unabsorbed 0.5-4 keV flux is 2.14 (-0.55/+1.13) × 10^(-8) erg/s/cm^2. The Follow-up X-ray Telescope (FXT) on board EP observed this source autonomously at 2026-03-14T22:54:51 (UTC, T0+211 s). The exposure time of this observation is 2.9ks. On-ground analysis of the FXT data found an uncatalogued source at R.A., Dec. = 211.8426, -23.4577 (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic), which is consistent with the WXT position. The average 0.5-10 keV spectrum can be fitted with an absorbed power law with a Galactic hydrogen column density of 0.22 (-0.07/+0.07) × 10^22 cm^-2 and a photon index of 2.21 (-0.27/+0.28). The derived average unabsorbed 0.5-10 keV flux is 5.11 (+0.46/-0.41) × 10^(-12) erg/s/cm^2. A follow-up observation with the EP/FXT was planned, and further information will be updated when the telemetry data is received. The optical follow-up observations were performed by Li et al. (GCN 44009), Li et al. (GCN 44013), Lipunov et al. (GCN 44014) and Pérez-García et al. (GCN 44015). We note that the SVOM/VT candidate (Li et al., GCN 44013) is located within the 10 arcsec error circle of EP/FXT. Further multi-band follow-up observations are encouraged to explore the nature of EP260314a. 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/44016. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42136] EP260314a: BOOTES-6/DPR optical upper limits at early times
by GCN Circulars 15 Mar '26

15 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44015 SUBJECT: EP260314a: BOOTES-6/DPR optical upper limits at early times DATE: 26/03/15 09:27:12 GMT FROM: I. Perez-Garcia at Institute of Astrophysics of Andalusia <ipg(a)iaa.es> I. Pérez-García, E. Fernández-García, M.D. Caballero-García, M. Gritsevich, S. Guziy, R. Sánchez-Ramírez, S.-Y. Wu, and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martín-Carrillo and L. Hanlon (UCD, Ireland), Y.-D. Hu (GXU), D. R. Xiong (Yunnan Observatories of CAS) and C. J. Pérez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report: Following the detection of EP260314a by Einstein Probe (Zhao et al., GCNC 44010), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) responded to this event starting on Mar 14, 23:00:01 UT (~ 8.5 min after trigger) with a 10s clear filter image. No new source is detected at the position of the proposed optical counterpart by SVOM/VT (Li et al., GCNC 44013) up to magnitude 16.3 using Gaia DR3 Gmag magnitude as reference on our first image. Further images were gathered and using ATLAS REFCAT2 as reference (Tonry et al. 2018) we get upper limits of: 18.5 (60s clear, at 23:03 UT), 20.9 (300s clear, at 23:06 UT) and 21.7 (600s clear, at 23:18 UT), in agreement with the upper limit reported by LCO (Li et al. GCNC 44009). We thank the staff at Boyden Observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/44015. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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