- vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 42251] GRB 260327A: AstroSat CZTI detection of a long burst
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44130 SUBJECT: GRB 260327A: AstroSat CZTI detection of a long burst DATE: 26/03/27 16:41:15 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910(a)gmail.com> A. Arya (IITB), A. Goyal (IITB), S. Salunke (IUCAA), Harsha K. H. (IUCAA), M. Tembhurnikar (IUCAA), G. Waratkar (Caltech/IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 260327A which was also detected by Konus-Wind (IPN Notices). The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve shows two emission episodes: a fainter episode preceding a brighter, longer episode by ~50 s. The brighter episode peaks at 2026-03-27 02:28:49.45 UTC. The measured peak count rate associated with the burst is 526 (+68, -68) counts/s above the background in the combined data of all quadrants, with a total of 7557 (+1305, -1387) counts. The local mean background count rate was 1236 (+5, -5) counts/s. We measure a T90 of 88 (+3, -4) s from the cumulative Veto light curve for both episodes. The source was also faintly detected in the 20-200 keV energy range. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb View this GCN Circular online at https://gcn.nasa.gov/circulars/44130. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42250] EP260327a: Gemini-North optical upper limits
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44129 SUBJECT: EP260327a: Gemini-North optical upper limits DATE: 26/03/27 13:44:41 GMT FROM: Rob Eyles-Ferris at U of Leicester <raje1(a)leicester.ac.uk> A. van Hoof (Radboud), G. Corcoran (UCD), J. Quirola-Vasquez (Radboud), R. A. J. Eyles-Ferris (Leicester), A. J. Levan (Radboud), A. Martin-Carrillo (UCD), F. E. Bauer (SSI and UTA), J. Chácon (PUC) and P. G. Jonker (Radboud) report on behalf of a larger collaboration: We observed the field of the fast X-ray transient EP260327a (Dai et al., GCN 44126) using the GMOS-N instrument mounted on the Gemini-North telescope. A series of 4x120 s exposures were taken in each of the r’ and z’ filters, starting at 2026-03-27 08:55:05 UT (3.00 hr after the trigger). We performed subtractions on our stacked images using template images from Hyper Suprime-Cam Strategic Program (Aihara et al. 2021, doi:10.1093/pasj/psab122) and compared the stacks and templates manually. Within the EP-FXT localisation (Dai et al., GCN 44126), we do not identify any new sources in our stacked images or subtractions in either band. For our stacked images, we calculate 3-sigma limits of r > 24.72 and z > 24.62 calibrated to nearby stars from PanSTARRS DR1 and not corrected for Galactic extinction. We do note the presence of a residual within the EP-FXT localisation in some of our subtractions at a position RA 215.3703, Dec 42.1406. This position is coincident with a DESI Legacy Survey object with a photometric redshift of 0.481 +/- 0.023. Given the magnitude of this object and depth of our images, we believe this to be a subtraction artefact rather than a real source. We thank the Gemini-North staff, particularly Denise Hung, for their rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/44129. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42249] EP260324a: GROWTH-India Telescope optical observation
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44128 SUBJECT: EP260324a: GROWTH-India Telescope optical observation DATE: 26/03/27 10:14:57 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s(a)iitb.ac.in> T. Mohan (IITB), V. Swain (IITB), D. Eappachen (IIA), A.P. Saikia (IITB), S. Patil (IITB), V. Bhalerao (IITB), G.C. Anupama (IIA), S. Barway (IIA) and R. Norbu (IAO) report on behalf of the GIT team: We observed the field of EP260324a (Wu et al., ATel 17728), with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2026-03-26 18:34:45 (UTC), i.e., 2.48 days after the trigger, and obtained multiple exposures in the r' and g' filters. We detect the optical counterpart in our difference image at position reported by Anumarlapudi et al., GCN 44120. (ZTF26aapviim / [AT 2026hir](https://www.wis-tns.org/object/2026hir)) | MJD (mid) | Filter | tmid-t0 (days) | Exposure Time (sec) | Magnitude (AB) | | ------------ | ------ | -------------- | ------------------- | -------------- | | 61125.7835185| g' | 2.489 | 1x300 | 18.08 +- 0.09 | | 61125.7871875| r' | 2.493 | 1x300 | 18.34 +- 0.09 | The measurement is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. Our magnitude for the optical counterpart is consistent with other optical observations (Anumarlapudi et al., GCN 44120). The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/. View this GCN Circular online at https://gcn.nasa.gov/circulars/44128. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42248] EP260327a: Global MASTER-Net observations report
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44127 SUBJECT: EP260327a: Global MASTER-Net observations report DATE: 26/03/27 08:54:22 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP260327a ( EP Team et al., GCN 44126) errorbox 510 sec after trigger time at 2026-03-27 06:03:11 UT, with upper limit up to 20.3 mag. The observations began at zenith distance = 74 deg. The sun altitude is -55.4 deg. The galactic latitude b = 66 deg., longitude l = 77 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3214974 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 561 | 2026-03-27 06:03:11 | MASTER-OAFA | (14h 22m 35.11s , +42d 24m 43.5s) | C | 100 | 19.7 | 696 | 2026-03-27 06:03:11 | MASTER-OAFA | (14h 22m 35.11s , +42d 24m 43.5s) | C | 370 | 20.3 | Coadd 678 | 2026-03-27 06:04:58 | MASTER-OAFA | (14h 22m 35.03s , +42d 24m 50.5s) | C | 120 | 19.8 | 819 | 2026-03-27 06:07:04 | MASTER-OAFA | (14h 22m 34.92s , +42d 24m 58.1s) | C | 150 | 19.8 | 930 | 2026-03-27 06:09:40 | MASTER-OAFA | (14h 22m 34.83s , +42d 25m 03.4s) | C | 60 | 19.5 | 990 | 2026-03-27 06:09:40 | MASTER-OAFA | (14h 22m 34.83s , +42d 25m 03.4s) | C | 180 | 20.2 | Coadd 995 | 2026-03-27 06:10:46 | MASTER-OAFA | (14h 22m 34.77s , +42d 25m 06.2s) | C | 60 | 19.5 | 1060 | 2026-03-27 06:11:51 | MASTER-OAFA | (14h 22m 34.69s , +42d 25m 09.4s) | C | 60 | 19.5 | 1126 | 2026-03-27 06:12:57 | MASTER-OAFA | (14h 22m 34.62s , +42d 25m 12.2s) | C | 60 | 19.5 | 1186 | 2026-03-27 06:12:57 | MASTER-OAFA | (14h 22m 34.62s , +42d 25m 12.2s) | C | 180 | 20.2 | Coadd 1192 | 2026-03-27 06:14:02 | MASTER-OAFA | (14h 22m 34.55s , +42d 25m 15.1s) | C | 60 | 19.5 | 1257 | 2026-03-27 06:15:08 | MASTER-OAFA | (14h 22m 34.47s , +42d 25m 18.0s) | C | 60 | 19.5 | 1323 | 2026-03-27 06:16:14 | MASTER-OAFA | (14h 22m 34.40s , +42d 25m 21.0s) | C | 60 | 19.5 | 1383 | 2026-03-27 06:16:14 | MASTER-OAFA | (14h 22m 34.40s , +42d 25m 21.0s) | C | 180 | 20.0 | Coadd 1389 | 2026-03-27 06:17:20 | MASTER-OAFA | (14h 22m 34.35s , +42d 25m 24.2s) | C | 60 | 19.5 | 1455 | 2026-03-27 06:18:25 | MASTER-OAFA | (14h 22m 34.26s , +42d 25m 27.1s) | C | 60 | 19.5 | 1521 | 2026-03-27 06:19:31 | MASTER-OAFA | (14h 22m 34.17s , +42d 25m 30.0s) | C | 60 | 19.5 | 1581 | 2026-03-27 06:19:31 | MASTER-OAFA | (14h 22m 34.17s , +42d 25m 30.0s) | C | 180 | 20.2 | Coadd 1586 | 2026-03-27 06:20:36 | MASTER-OAFA | (14h 22m 34.09s , +42d 25m 32.9s) | C | 60 | 19.5 | 1651 | 2026-03-27 06:21:42 | MASTER-OAFA | (14h 22m 34.03s , +42d 25m 35.6s) | C | 60 | 19.4 | 1717 | 2026-03-27 06:22:47 | MASTER-OAFA | (14h 22m 33.95s , +42d 25m 38.2s) | C | 60 | 19.5 | 1777 | 2026-03-27 06:22:47 | MASTER-OAFA | (14h 22m 33.95s , +42d 25m 38.2s) | C | 180 | 20.2 | Coadd 1782 | 2026-03-27 06:23:53 | MASTER-OAFA | (14h 22m 33.88s , +42d 25m 41.1s) | C | 60 | 19.5 | 1848 | 2026-03-27 06:24:59 | MASTER-OAFA | (14h 22m 33.80s , +42d 25m 43.6s) | C | 60 | 19.5 | 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/44127. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42247] EP260327a: Einstein Probe detection of an X-ray transient
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44126 SUBJECT: EP260327a: Einstein Probe detection of an X-ray transient DATE: 26/03/27 08:28:31 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> C. Y. Dai (NJU), Z. H. Yang, Q. C. Zhao (IHEP), W. F. Wen (SZTU), H. W. Pan (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 EP260327a. The transient triggered EP-WXT (ID: 01709259176) at 2026-03-27T05:54:41 (UTC). The WXT position of the source is R.A. = 215.371 deg, DEC = 42.130 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. = 215.3746 deg, DEC = 42.1396 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/44126. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42246] GRB 260310A / AT 2026fgk: COLIBRÍ photometric evidence of the emerging supernova
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44125 SUBJECT: GRB 260310A / AT 2026fgk: COLIBRÍ photometric evidence of the emerging supernova DATE: 26/03/27 08:14:57 GMT FROM: enriquemm(a)astro.unam.mx Marion Guelfand (CPPM), Enrique Moreno Méndez (UNAM), Rosa L. Becerra (UNAM), Antonio de Ugarte Postigo (LAM), Noémie Globus (UNAM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (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), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), and Benjamin Schneider (LAM) and report: We imaged the field of the optical counterpart AT 2026fgk (O’Neill et al. 2026, TNS Discovery Report 294132; Hinds et al., AstroNote 2026-65) of GRB 260310A (Hamburg & Meegan, GCN 43975; Salunke et al., GCN 43958) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-03-27 02:46 to 03:59 UTC (from 16.90 to 16.95 days after the trigger) and obtained 1080 seconds in g, r, and i filters, and 3240 seconds of exposure in the z filter. The data were reduced, coadded and analysed with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, it is in the AB system, and it is not corrected for Galactic extinction. We have obtained spectral energy distributions at multiple epochs prior to T+12 days, all of which are well described by a single power law with a spectral index β ≈ −1. However, tonight we observe a significant increase in the g−r and g-i colours and a decrease in the i−z colour indicating the emergence of a thermal component in the spectral energy distribution. This behaviour suggests the onset of a supernova, in agreement with the report by de Ugarte Postigo et al. (GCN Circ. 44124) Further observations and analysis are ongoing. 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/44125. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42245] GRB 260310A: OSIRIS+/GTC spectroscopic detection of the associated BL-Ic, SN 2026fgk
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44124 SUBJECT: GRB 260310A: OSIRIS+/GTC spectroscopic detection of the associated BL-Ic, SN 2026fgk DATE: 26/03/27 07:39:02 GMT FROM: Antonio de Ugarte Postigo at LAM, CNRS <adeugartepostigo(a)gmail.com> A. de Ugarte Postigo (LAM), S. Geier (GTC), L. Izzo (INAF/OACN and DARK/NBI), D. B. Malesani (DAWN/NBI and Radboud), A. Martin-Carrillo (UCD), C. C. Thoene (AbAO), M. A. Aloy (UV), J. P. U. Fynbo (DAWN/NBI), L. Galbany (IEEC-CSIC), G. Lombardi (GTC), N. A. Rakotondrainibe (LAM), B. Schneider (LAM), N. R. Tanvir (Univ. Leicester), D. González González (GTC) report: We observed the optical counterpart (AT2026fgk, a.k.a. GOTO26buh, O’Neill et al. 2026, TNS Discovery Report 294132; Hinds et al., AstroNote 2026-65) of GRB 260310A (Hamburg & Meegan, GCN 43975; Salunke et al., GCN 43958) using the Gran Telescopio Canarias (GTC) equipped with the OSIRIS+ instrument. A total of 3 spectra of 900 s were secured, starting on 2026-03-27 at 04:25:40 UT (16.98 days after trigger), using grism R1000B. Continuum is visible over the full range 3610-7880 AA. The spectrum has evolved from the power-law continuum reported in de Ugarte Postigo et al. (GCN 43984) and now shows undulations expected in a SN spectrum. Indeed, using SNID to classify the SN we get a best match to a type Ic-BL SN close to maximum light. Our results allow us to conclusively identify the presence of a SN, linking the event to a massive stellar collapse. View this GCN Circular online at https://gcn.nasa.gov/circulars/44124. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42244] The EP-WXT trigger 01709259173 is likely a flaring star
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44123 SUBJECT: The EP-WXT trigger 01709259173 is likely a flaring star DATE: 26/03/27 04:19:32 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Z. H. Yang(IHEP), C. Y. Dai (NJU), Q. C. Zhao(IHEP), W. F. Wen(SZTU) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709259173 at the time of 2026-03-26T22:01:59, is likely a stellar flare associated with UCAC4 220-087219. The estimated flux of the flare is around 1.92e-11 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 4e+31 erg/s. 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/44123. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42243] GRB 260310A / AT2026fgk: Late-time infrared detection with MIRAGE on the MDM 1.3m telescope
by GCN Circulars 27 Mar '26

27 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44122 SUBJECT: GRB 260310A / AT2026fgk: Late-time infrared detection with MIRAGE on the MDM 1.3m telescope DATE: 26/03/27 00:39:12 GMT FROM: Kishalay De at Columbia University <kde1(a)mit.edu> R. B. Effress, B. T. Gebreamlak, B. O. Goldman, T. Goodman, J. Kalish, L. Koo, T. Lack, S. A. Lawsky, S. L. Manyan, M. Nebart, K. N. Oqueli-White, A. Ramadorai, N. A. Rodgers, T. A. Sabin, E. Sharman, C. Wu, L. Zheng, R. Zheng, G. Mo, V. Karambelkar, S. Ibrahim, N. Aftab, D. Schiminovich, K. De (Columbia University) We observed the field of GRB 260310A detected by Fermi/GBM (Fermi GB team GCN 43951) and AstroSat CZTI (Salunke et al. GCN 43958), during commissioning operations of the MDM InfraRed Astronomy InGaAs Explorer (MIRAGE) instrument on the MDM 1.3m telescope. Observations were carried out starting at UTC 2026-03-22 08:50, approximately three weeks after the GRB trigger. We obtained a series of dithered exposures in J-band and Hs-band amounting to a total exposure time of 600 s each. Images were aligned, stacked and calibrated to the 2MASS catalog. Performing forced photometry at the position of the optical counterpart (AT2026fgk; Konno et al. GCN 43974, Hinds et al. AstroNote 2026-65; O’Neill et al. TNS Discovery Report 294132), we clearly detect a point source with magnitudes J = 18.40 +/- 0.14 Vega mag Hs = 17.07 +/- 0.16 Vega mag The measurements confirm continued infrared fading of the source (Gao et al. GCN 44110). Note that these measurements did not include image subtraction, though the host contamination is expected to be small. Further observations are planned and analysis is being improved. MIRAGE is a new YJH-band near-infrared imager for the MDM 1.3m telescope. We thank the MDM Observatory staff for supporting the commissioning observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/44122. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42242] IPN triangulation of GRB 260320A
by GCN Circulars 26 Mar '26

26 Mar '26

TITLE: GCN CIRCULAR NUMBER: 44121 SUBJECT: IPN triangulation of GRB 260320A DATE: 26/03/26 23:15:43 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, E. Burns on behalf of the IPN, C. Wang (IHEP), S. Xiong (IHEP), S. Zhang (IHEP), J. Wei (NAOC), B. Cordier (CEA) on behalf of the SVOM-GRM team, C. Wang (IHEP), S. Xiong (IHEP), S. Zhang (IHEP) on behalf of the Insight-HXMT team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 260320A (NuSTAR-ACS detection: Waratkar et al., GCN 44064; Insight-HXMT/HE detection: Luo et al., GCN 44077; Glowbug detection: Cheung et al., GCN 44093; GRID detection: Li et al., GCN 44109) was detected by NuSTAR (ACS), SVOM (GRM), Insight-HXMT(HE), Konus-Wind, Glowbug, GRID-11B, GRID-10B, and Mars-Odyssey (HEND) at about 70804 s UT (19:40:04). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 316.117 (21h 04m 28s) +6.388 ( +6d 23' 17") Corners: 318.993 (21h 15m 58s) +11.535 (+11d 32' 06") 313.686 (20h 54m 45s) -0.693 (+00d 41' 36") 313.683 (20h 54m 44s) -1.165 (-01d 09' 54") 318.941 (21h 15m 46s) +11.286 (+11d 17' 09") --------------------------------------------- The error box area is 1.3 sq. deg, and its maximum dimension is 13.8 deg (the minimum one is 5.7 arcmin). The Sun distance was 42 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB260320_T70801/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. View this GCN Circular online at https://gcn.nasa.gov/circulars/44121. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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