August 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 39606] LIGO/Virgo/KAGRA S250818k: VLA upper limits on AT2025ulz
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41542 SUBJECT: LIGO/Virgo/KAGRA S250818k: VLA upper limits on AT2025ulz DATE: 25/08/25 14:13:32 GMT FROM: muskan.yadav(a)students.uniroma2.eu R. Ricci, M. Yadav, E. Troja (U Rome) report on behalf of the ERC BHianca team: We observed the optical transient AT2025ulz/ZTF25abjmnps (Stein et al. GCN 41414; Hall et al. GCN 41433; Karambelkar et al. GCN 41436; O’Connor et al. GCN 41452) within the localization of the candidate gravitational wave event S250818k (LVKC GCN 41437; GCN 41440) with the Very Large Array in S-band and C-band at the centre frequency of 3 GHz and 6 GHz respectively with a bandwidth of 2 GHz and 4 GHz on Aug 24st 2025, 5.9 days after the GW trigger. A possible radio counterpart with flux 77 +/- 16 microJy/beam at 3 GHz was claimed by Bruni et al. (GCN 41500). After reducing the data using the latest version of the CASA VLA pipeline (v6.6.1) and standard imaging procedures, we found no detection at the transient position down to a 3-sigma flux density upper limit of about 40 microJy/beam and 25 microJy/beam for 3 GHz and 6 GHz respectively. We thank the VLA staff for promptly executing the observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/41542. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39605] LIGO/Virgo/KAGRA S250818k: nature of the AT2025ulz/ZTF25abjmnnps OT
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41541 SUBJECT: LIGO/Virgo/KAGRA S250818k: nature of the AT2025ulz/ZTF25abjmnnps OT DATE: 25/08/25 13:17:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.M. Lipunov, (Lomonosov MSU), In several recent telegrams (GCN 41532, 41538) the nature of the AT2025ulz/ZTF25abjmnps source is discussed. An alternative between the KN and SN II models has emerged. The unusual observable properties of the optical flare are emphasized. This alternative seems strange. For example, where can SN II appear in an elliptical galaxy? In this regard, I propose to include a third possible model, namely the merger of two heavy white dwarfs (O-Ne-Mg dwarfs) turning into a neutron star - a dumbbell with powerful radiation of gravitational waves [1]. As was shown earlier, such a phenomenon can generate an unusual form of gravitational wave impulse, which can be taken for a phenomenon caused by a terrestrial artifact. Is this not related to the fact that the initial probability of a terrestrial nature turned out to be more than 70%? [1] Lipunov V.M., Double O-Ne-Mg white dwarfs merging as the source of the powerful gravitational waves for LIGO/VIRGO type interferometers., New Astronomy, Volume 56, p. 84-85, 2017 https://doi.org/10.1016/j.newast.2017.04.013 View this GCN Circular online at https://gcn.nasa.gov/circulars/41541. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39604] LIGO/Virgo/KAGRA S250818k: Pan-STARRS imaging confirms re-brightening of SN2025ulz
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41540 SUBJECT: LIGO/Virgo/KAGRA S250818k: Pan-STARRS imaging confirms re-brightening of SN2025ulz DATE: 25/08/25 13:07:11 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro(a)gmail.com> J. H. Gillanders (Oxford), M. E. Huber, K. C. Chambers (IfA, Univ. Hawaii), S. J. Smartt, K. W. Smith (Oxford/QUB), S. Srivastav, F. Stoppa, H. Stevance, J. Tweddle (Oxford), M. Nicholl, D. R. Young, A. Aamer, C. R. Angus, M. D. Fulton, D. Magill, M. McCollum, T. Moore, S. Sim, J. Weston, X. Sheng (QUB), T.-W. Chen (NCU, Taiwan), L. Shingles (GSI/QUB), P. Ramsden (Birmingham/QUB), A. S. B. Schultz, T. de Boer, J. Fairlamb, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, G. Paek, I. A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii), A. Rest (STScI), C. Stubbs (Harvard). We have been observing the optical transient SN2025ulz (Banerjee et al., GCN 41532), formerly AT2025ulz (Stein et al., GCN 41414), the candidate optical counterpart associated with the sub-threshold gravitational wave event S250818k (LVK Collaboration, GCNs 41437, 41440) using the Pan-STARRS twin telescope system (Chambers et al., 2016, arXiv e-prints, 1612.05560); see also Gillanders et al. (GCN 41454) and Smartt et al. (GCN 41493). Our observations span grizy-bands, but here we report on the optical re-brightening evident in our i-band observations. On each of MJDs 60909.26, 60910.26, 60911.26 and 60912.26, we observed SN2025ulz for a total exposure time of 1800s. The images were processed with the Pan-STARRS pipeline, where, after astrometric and photometric calibration, reference images were subtracted from the target stacked images (Magnier et al., 2020a, ApJS, 251, 3; Magnier et al., 2020b, ApJS, 251, 6; Waters et al., 2020, ApJS, 251, 4). For this process, we utilise proprietary data to compile significantly deeper reference stacks (~3400s) than those that are publicly available through the STScI website (~300s) and our stacked target images (1800s). From these difference images, we measure the following preliminary AB magnitudes: MJD t-t0 (days) Filter AB mag 60909.26 4.2 i 22.4 +/- 0.3 60910.26 5.2 i 22.5 +/- 0.3 60911.26 6.2 i 22.1 +/- 0.2 60912.26 7.2 i 21.6 +/- 0.1 Here, t0 corresponds to the GW trigger time (LVK Collaboration, GCN 41437). SN2025ulz has risen in our i-band observations by ~0.5 mag (~0.9 mag) in the last one day (two days). While there are barriers to accurately measuring the photometry of this source (e.g., it is relatively faint; it lies close to the bright nucleus and body of the host), our photometry values, and the inferred re-brightening, are robust, given our access to deep reference stacks. We note that these are vital to accurately infer the true brightness of the transient, as performing difference imaging with a shallower reference image can lead to systematic errors (as much as ~0.7 AB mag, in the specific case of SN2025ulz utilising the public reference stack available through the STScI website). Re-brightening of SN2025ulz has been previously noted by Liu et al. (GCN 41461), Freeburn et al. (GCN 41507) and Angulo et al. (GCN 41518). Our observed re-brightening supports the interpretation of SN2025ulz being a young SN, based on the VLT spectral observations reported by ENGRAVE (Banerjee et al., GCN 41532). Our consistent i-band rise is likely to suggest it is now on a radioactively powered rise following an initial shock-cooling phase, and thus indicates that SN2025ulz is likely not the optical counterpart to S250818k. Further Pan-STARRS observations are continuing to determine if the colour and lightcurve shape remains consistent with a type II or IIb supernova, to compare with the conclusions of Kasliwal et al. (GCN 41538). Operation of the Pan-STARRS1 and Pan-STARRS2 telescopes is primarily supported by the National Aeronautics and Space Administration under Grant No. NNX12AR65G and NNX14AM74G, issued through the SSO Near-Earth Object Observations Program. Data processing is enabled by Queen's University Belfast and the University of Oxford, enabled through STFC grants ST/Y001605/1, ST/T000198/1 and ST/X001253/1, the Royal Society, and the Hintze Centre for Astrophysical Surveys. View this GCN Circular online at https://gcn.nasa.gov/circulars/41540. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39603] GRB 250823A: Swift-BAT refined analysis
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41539 SUBJECT: GRB 250823A: Swift-BAT refined analysis DATE: 25/08/25 12:44:24 GMT FROM: Rahul Gupta at NASA GSFC <rahul.gupta(a)nasa.gov> C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU), M. H. Siegel (PSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250823A (trigger #1344586) (Siegel, et al., GCN Circ. 41511). The BAT ground-calculated position is RA, Dec = 297.465, -24.986 deg which is RA(J2000) = 19h 49m 51.7s Dec(J2000) = -24d 59' 09.0" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 75%. The mask-weighted BAT light curve shows multi-peaked emission starting from ~T-25 to ~T+180 sec. T90 (15-350 keV) is 193.60 +- 10.19 sec (estimated error including systematics). The time-averaged spectrum from T-23.84 to T+180.82 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.76 +- 0.16. The fluence in the 15-150 keV band is 1.8 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+4.24 sec in the 15-150 keV band is 1.1 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1344586 View this GCN Circular online at https://gcn.nasa.gov/circulars/41539. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39602] LIGO/Virgo/KAGRA S250818k: Continued Keck I LRIS spectroscopy of ZTF25abjmnps (AT2025ulz)
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41538 SUBJECT: LIGO/Virgo/KAGRA S250818k: Continued Keck I LRIS spectroscopy of ZTF25abjmnps (AT2025ulz) DATE: 25/08/25 10:04:54 GMT FROM: Mansi Kasliwal at Caltech <mansikasliwal(a)gmail.com> Mansi M. Kasliwal (Caltech), Viraj Karambelkar (Caltech), Christoffer Fremling (Caltech), Tomas Ahumada (Caltech), Xander J. Hall (CMU), Daniel A. Perley (LJMU), Shreya Anand (Stanford), Chang Liu (Northwestern), Kaustav Das (Caltech), Varun Bhalerao (IIT-B), Vishwajeet Swain (IIT-B), Aditya Saikia (IIT-B) report on behalf of a larger ZTF and GROWTH collaboration We continue to observe ZTF25abjmnps (AT2025ulz; Stein et al. GCN 41414) with the LRIS spectrograph on Keck I. Our latest epoch starts at UTC 2025-08-25 06:50. We reduce the data with lpipe (Perley et al. 2019) and subtract a spectrum at an earlier epoch to understand the evolution (Karambelkar et al. GCN 41436). As reported by Banerjee et al. GCN 41532, we also see a feature with an absorption minimum at 6720A. If this is Halpha, this would imply a velocity of 17000 km/s at z=0.0848 (we measure a higher velocity than what was reported in Banerjee et al. GCN 41532). However, we posit the classification of this transient as a supernova or a kilonova currently remains ambiguous. If it is a supernova, it is an unusual supernova for at least four reasons: (i) There is no robust (rlap>5) spectral match in the SNID library, (ii) No supernova light curve in the ZTF supernova library matches especially the blue-to-red color evolution at this early phase (e.g. Busmann et al. GCN 41535), (iii) The feature at 6720A is not smooth in shape and has additional structure, (iv) There appear to be other weak, broad undulations in the spectra. If it is a kilonova, all photometric data in-hand continue to be consistent with this hypothesis, however, additional theoretical modeling may be needed to fully explain the spectra. Looking ahead, we encourage continued follow-up of the panchromatic light curve, including the radio and X-ray bands, to unambiguously classify this source. View this GCN Circular online at https://gcn.nasa.gov/circulars/41538. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39601] GRB 250821B: AstroSat CZTI detection
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41537 SUBJECT: GRB 250821B: AstroSat CZTI detection DATE: 25/08/25 09:32:36 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in> M. Tembhurnikar (IUCAA), A. Arya (IITB), G. Waratkar (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 GRB 250821B which was also detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 41473 and 41477), SVOM/GRM (SVOM team, GCN Circ. 41486), Konus-Wind (Frederiks et al., GCN Circ. 41508), and Insight-HXMT (Wang et al., GCN Circ. 41533). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-08-21 16:07:47.95 UTC. The measured peak count rate associated with the burst is 343 (+153, -46) counts/s above the background in the combined data of all quadrants, with a total of 218 (+60, -62) counts. The local mean background count rate was 252 (+10, -12) counts/s. Using cumulative rates, we measure a T90 of 1.2 (+0.2, -0.5) s. The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-08-21 16:07:47.16 UTC. The measured peak count rate associated with the burst is 1724 (+84, -94) counts/s above the background in the combined data of all quadrants, with a total of 2373 (+175, -194) counts. The local mean background count rate was 1175 (+9, -11) counts/s. We measure a T90 of 1.9 (+1.0, -0.2) s from the cumulative Veto light curve. 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/41537. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39600] GRB 250819A: AstroSat CZTI detection
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41536 SUBJECT: GRB 250819A: AstroSat CZTI detection DATE: 25/08/25 09:11:22 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in> M. Tembhurnikar (IUCAA), G. Waratkar (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 GRB 250819A which was also detected by Insight-HXMT (Wang et. al., GCN Circ. 41457), and SVOM/GRM (SVOM team, GCN Circ. 41458). The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-08-19 17:49:46.59 UTC. The measured peak count rate associated with the burst is 396 (+68, -65) counts/s above the background in the combined data of all quadrants, with a total of 1066 (+262, -291) counts. The local mean background count rate was 1300 (+10, -12) counts/s. We measure a T90 of 3.3 (+1.8, -1.0) s from the cumulative Veto light curve. The source was also faintly detected in the CZT detectors 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/41536. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39599] LIGO/Virgo/KAGRA S250818k: FTW Observations Show Continued Reddening of AT 2025ulz
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41535 SUBJECT: LIGO/Virgo/KAGRA S250818k: FTW Observations Show Continued Reddening of AT 2025ulz DATE: 25/08/25 09:09:19 GMT FROM: Malte Busmann at Ludwig-Maximilians-Universität München <m.busmann(a)physik.lmu.de> Malte Busmann (LMU), Xander J. Hall (Carnegie Mellon U.), Daniel Gruen (LMU), Brendan O’Connor (Carnegie Mellon U.), Antonella Palmese (Carnegie Mellon U.), and Mansi Kasliwal (Caltech) report: We observed the source AT 2025ulz reported by Stein et al. (GCN 41414) possible counterpart to the LVK sub-threshold event S250818k (GCN 41437, 41440), with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the g, i, and J bands simultaneously starting at 2025-08-24T19:33:25 for 20 x 180 s with a few interruptions due to clouds. The difference imaging with templates from the Legacy Survey for the g-band and PS1 for the i-band, we report that AT 2025ulz has g - i ~ 1.7 AB mag. We note our differenced i-band brightness is consistent with observations reported by Freeburn et al. (GCN 41507) and Angulo et al. (GCN 41518). The magnitudes are calibrated against the PS1 catalog and not corrected for Galactic extinction. Further analysis is underway. We thank Christoph Ries from the Wendelstein Observatory staff for obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/41535. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39598] LIGO/Virgo/KAGRA S250818k: MASTER predicovery limits of the AT2025ulz/ZTF25abjmnps KN candidate
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41534 SUBJECT: LIGO/Virgo/KAGRA S250818k: MASTER predicovery limits of the AT2025ulz/ZTF25abjmnps KN candidate DATE: 25/08/25 08:21:58 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, N.Tiurina, D.Vlasenko, P.Balanutsa, I.Panchenko, A.Sankovich, A.Chasovnikov K.Zhirkov, G.Antipov, I.Gorbunov, A.Sosnovskij, Yu.Tselik, Ya.Kechin, V.Senik, V.Topolev (Lomonosov MSU), O.Gress, N.Budnev, O.Ershova (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), D.Buckley (SAAO), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), 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) Global MASTER robotic net [1] observed the field with AT2025ulz/ZTF25abjmnps, reported by Stein et al. (GCN 41414) and possibly associated with the candidate gravitational wave signal S250818k (LVK Collaboration, GCN 41437, 41440) before and after trigger time. At the location of AT2025ulz the twin MASTER600-Tunka telescope (Cmos QHY 6060, FOW = 18 square degress) did not detect a source with next 5-sigma limits: Date UT Tstart-Ttrig Exp Filter tube lim (middle) (day) (s) 250815 14:55:18 -3.12 60 Clear East 19.8 250822 16:52:05 3.95 8x60 Clear West 20.9 250823 15:37:06 4.90 38x60 Clear West 21.8 The first observation was a lucky coincidence. Since there was no automatic LVC alert, subsequent observations had to be carried out in the Internet telescope mode, taking into account the specific quality of the weather. [1] V.M. Lipunov, V.G. Kornilov, E.Gorbovskoy, N. Tiurina & A.Kuznetsov, 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/41534. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39597] GRB 250821B: Insight-HXMT detection
by GCN Circulars 25 Aug '25

25 Aug '25

TITLE: GCN CIRCULAR NUMBER: 41533 SUBJECT: GRB 250821B: Insight-HXMT detection DATE: 25/08/25 03:30:20 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> Chen-Wei Wang, Wen-Jun Tan, Shao-Lin Xiong, and Chao Zheng report on behalf of the Insight-HXMT team: At 2025-08-21T16:07:47.500 (T0), Insight-HXMT/HE detected the bright intermedium duration burst GRB 250821B, which is also detected by Fermi/GBM (Fermi GBM team., GCN #41473), SVOM/GRM (Tan et al., GCN #41486) and Konus-Wind (D. Frederiks et al., GCN #41508). The Insight-HXMT/HE light curve mainly consists of multi-pulses with a T90 of 2.05 +1.70/-0.45 s. The 1s peak rate, measured from T0-0.075 s, is 11927 cnts/sec. The total counts from this burst is 15817 counts. The HXMT/HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb250821B.png All measurements above are made with the CsI detectors 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://www.hxmt.org. View this GCN Circular online at https://gcn.nasa.gov/circulars/41533. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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