August 2024 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 34945] GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37072 SUBJECT: GRB 240805B: AbAO, CrAO, and Terskol optical upper limits DATE: 24/08/06 14:20:22 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex(a)gmail.com> N. Pankov (HSE, IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), R. Ya. Inasaridze (AbAO), A. Shikherin (KIAM) report on behalf of GRB-IKI-FuN: We observed the field of GRB 240805B detected by Swift (Williams et al, GCN 37043; Goad et al, GCN 37053) with AS-32 0.7-meter telescope of Abastumani observatory (AbAO) in R-filter, ZTSh 2.6-meter telescope of CrAO in R-filter, and K800 0.8-meter telescope of Terskol observatory in clear filter. The observations began on 2024-08-05 at 17:30 UT at AbAO (i.e. 3.1 hr since Swift trigger) in variable conditions. We obtain upper limits on the optical counterpart found and confirmed in (Moskvitin et al, GCN 37055; Du et al, GCN 37062): Date UT start t-T0 Exp. Filter OT Err. UL Observ./Scope (mid, days) (s) (3-sigma) 2024-08-05 17:30:52 0.14442 52x60 R n/d n/d 20.2 AbAO/AS-32 2024-08-05 19:50:58 0.24449 30*120 R n/d n/d 20.5 CrAO/ZTSh 2024-08-05 20:10:07 0.23695 44*30 CR n/d n/d 17.0 Terskol/K800 The photometry was calibrated against nearby stars of USNO-B1.0 (R2 magnitudes). The upper limits are in agreement with no detections by (Zhu et al, GCN 37050; Strausbaugh et al, GCN 37052; Siegel & Williams, GCN 37057; Maksut et al, GCN 37060). View this GCN Circular online at https://gcn.nasa.gov/circulars/37072. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34944] Konus-Wind detection of GRB 240804A (a counterpart of EP240804a)
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37071 SUBJECT: Konus-Wind detection of GRB 240804A (a counterpart of EP240804a) DATE: 24/08/06 13:53:55 GMT FROM: Dmitry Frederiks at Ioffe Institute <fred(a)mail.ioffe.ru> D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: A long-duration GRB 240804A was detected by Konus-Wind (KW) in the waiting mode at T0=T0(KW)~21:36:48 UT. A Bayesian block analysis of the KW data in the 100-400 keV band reveals a >4 sigma count rate increase in the interval from ~T0-5 s to ~T0+33 s. Corrected for the propagation time, the burst started ~5 s before the start time of the fast X-ray transient EP240804a (T0(EP)=21:36:53 UT; Wang et al., GCN 37034). The burst source is located in the southern ecliptic hemisphere, which is consistent with the EP240703a localization. The positional and temporal coincidence of GRB 240804A with the EP transient supports the conclusion that EP240804a is the GRB counterpart. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB240804A/ The time-integrated spectrum of the burst, measured from T0-5 s to T0+33 s, cat be described by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = (0.16 ± 1.25) and Ep = (310 ± 164) keV. The total burst fluence is (2.56 ± 1.11)x10^-6 erg/cm^2, and the 2.944 s peak energy flux, measured from T0-1.96 s, is (2.1 ± 0.9)x10^-7 erg/cm^2. (both in the 20 keV - 10 MeV energy range). Assuming the redshift z=3.662 (Bochenek et al., GCN 37039) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the burst isotropic energy release E_iso to (7.2 ± 3.1)x10^52 erg, the isotropic peak luminosity L_iso to (3.7 ± 1.6)x10^52 erg/s, and the rest-frame peak spectral energy Ep,z to (1450 ± 770) keV. With the obtained estimates, GRB 240804A lies at the upper edge, but is consistent, within errors, with 'Amati' and 'Yonetoku' relations, for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB240804A/GRB240804A_rest_frame.pdf All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/37071. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34943] Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37070 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB DATE: 24/08/06 13:14:16 GMT FROM: Christian Malacaria at ISSI <cmalacaria.astro(a)gmail.com> C. Malacaria (INAF-OAR) reports on behalf of the Fermi-GBM Team: The Fermi Gamma-ray Burst Monitor (GBM) trigger 240806402/744629911 at 09:38:26.19 UT on 6 August 2024, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/ View this GCN Circular online at https://gcn.nasa.gov/circulars/37070. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34942] Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37070 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB DATE: 24/08/06 13:14:16 GMT FROM: Christian Malacaria at ISSI <cmalacaria.astro(a)gmail.com> C. Malacaria (INAF-OAR) reports on behalf of the Fermi-GBM Team: The Fermi Gamma-ray Burst Monitor (GBM) trigger 240806402/744629911 at 09:38:26.19 UT on 6 August 2024, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/ View this GCN Circular online at https://gcn.nasa.gov/circulars/37070. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34941] EP240806a: EP-FXT detection of the X-ray emission
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37069 SUBJECT: EP240806a: EP-FXT detection of the X-ray emission DATE: 24/08/06 13:02:16 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y. Wang (PMO, CAS), Y. J. Zhang (THU), Q. Y. Wu, Y. Liu, H. W. Pan, Z. X. Ling, C. C. Jin, C. Zhang, H. Q. Cheng, W. Chen, C. Z. Cui, D. W. Fan, H. B. Hu, M. H. Huang, D. Y. Li, H. Y. Liu, M. J. Liu, Z. Z. Lv, T. Y. Lian, X. Mao, X. Pan, H. Sun, W. X. Wang, Y. L. Wang, X. P. Xu, Y. F. Xu, H. N. Yang, W. Yuan, M. Zhang, W. D. Zhang, W. J. Zhang, Z. Zhang, D. H. Zhao (NAOC, CAS), Y. Chen, S. M. Jia, W. W. Cui, D. W. Han, C. K. Li, L. M. Song, X. F. Zhao, J. Zhang, S. N. Zhang (IHEP, CAS), E. Kuulkers, A. Santovincenzo (ESA), P. O'Brien (Univ. of Leicester), K. Nandra, A. Rau (MPE), B. Cordier (CEA) on behalf of the Einstein Probe team Following the detection of the fast X-ray transient EP240806a (Wu et al., GCN 37063), we performed an observation of EP240806a with the Follow-up X-ray Telescope (FXT) on board the Einstein Probe (EP) mission. The observation began at 2024-08-06T05:39:11, about 1 hour after the EP-WXT detection. The exposure time is 6058 seconds. Within the error circle of the WXT source, a slowly fading X-ray source was detected at R.A. = 11.4864 deg, DEC = 5.0941 deg, with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic), which is consistent with the position of the optical source detected by GSP (Li et al., GCN 37064). The average 0.5-10 keV spectrum can be fitted with an absorbed power law with a photon index of 2.2(-0.7, +0.7) (with a freely fitted column density value of 1.3(-0.7, +0.7) x 10^21 cm^-2). The derived average unabsorbed 0.5-10 keV flux is 1.2(-0.1, +0.1) x 10^(-12) erg/s/cm^2. There is no cataloged X-ray source within the error circle, suggesting this source being associated with EP240806a. 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/37069. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34940] GRB 240626B: VZLUSAT-2 detection
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37068 SUBJECT: GRB 240626B: VZLUSAT-2 detection DATE: 24/08/06 12:20:03 GMT FROM: Andras Pal at Konkoly Observatory <apal(a)szofi.net> A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration. We report a detection of a likely long-duration GRB 240626B by the GRB detector on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/). The event was triggered by INTEGRAL/SPI-ACS (trigger no. 10775). The GOES-P X-ray flux does not show any increase at the time of this detection, therefore, it is unlikely to be a solar flare and we consider it as a GRB candidate. The data acquisition was performed by the GRB detector unit no. 1. The detection was confirmed at the peak time 2024-06-26 06:41:03 UTC. The T90 duration is 10 s and the significance during T90 reaches 7.5 sigma. The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB240626B_GCN_VZLUSAT2.pdf All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/ The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral. View this GCN Circular online at https://gcn.nasa.gov/circulars/37068. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34939] GRB 240624B: VZLUSAT-2 detection
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37067 SUBJECT: GRB 240624B: VZLUSAT-2 detection DATE: 24/08/06 12:19:22 GMT FROM: Andras Pal at Konkoly Observatory <apal(a)szofi.net> A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration. The long-duration GRB 240624B (Fermi/GBM detection: GCN 36749; GRBAlpha detection: GCN 36759; CALET/CGBM detection: GCN 36764; Konus/Wind detection trigger at 2024-06-24 19:19:51.634 UTC) was detected by the GRB detectors on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/). The data acquisition was performed by the GRB detector units no. 0 and no. 1. The detection was confirmed at the peak time 2024-06-24 19:19:46 (19:19:44) UTC. The T90 duration is 6 s (5 s) and the significance during T90 reaches 5.3 sigma (12 sigma) for detector unit no. 0 (no. 1). The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB240624B_GCN_VZLUSAT2.pdf All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/ The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral. View this GCN Circular online at https://gcn.nasa.gov/circulars/37067. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34938] GRB 240619C: VZLUSAT-2 detection
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37066 SUBJECT: GRB 240619C: VZLUSAT-2 detection DATE: 24/08/06 12:18:13 GMT FROM: Andras Pal at Konkoly Observatory <apal(a)szofi.net> A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration. The long-duration GRB 240619C (AstroSat/CZTI detection: GCN 36711; Fermi/GBM detection: GCN 36716; NuSTAR detection: GCN 36718; INTEGRAL/SPI-ACS peak detection at 2024-06-19 ~23:44:52 UTC) was detected by the GRB detectors on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/). The data acquisition was performed by the GRB detector units no. 0 and no. 1. The detection was confirmed at the peak time 2024-06-19 23:44:50 UTC. The T90 duration is 25 s (24 s) and the significance during T90 reaches 18 sigma (22 sigma) for detector unit no. 0 (no. 1). The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB240619C_GCN_VZLUSAT2.pdf All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/ The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral. View this GCN Circular online at https://gcn.nasa.gov/circulars/37066. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34937] EP 240806A: LCO optical observations
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37065 SUBJECT: EP 240806A: LCO optical observations DATE: 24/08/06 12:17:28 GMT FROM: luca.izzo(a)inaf.it L. Izzo (INAF-OACn & DARK/NBI), D. B. Malesani (DAWN/NBI and Radboud Univ.) report: We observed the field of EP 240806A (Wu et al., GCN #37063) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at Siding Spring Observatory, Australia. Observations started on August 06 at 10:30:58 UT (5.7 hours after the GRB trigger). We obtained a series of 3x180 s images in the r filter. In the stacked image, we detect a new source within the WXT error circle at a position consistent with the source reported by Li et al. (GCN #37064). We measure a preliminary magnitude of r = 21.9 +/- 0.2 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 101004719. View this GCN Circular online at https://gcn.nasa.gov/circulars/37065. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 34936] EP240806a: GSP optical counterpart detection
by GCN Circulars 06 Aug '24

06 Aug '24

TITLE: GCN CIRCULAR NUMBER: 37064 SUBJECT: EP240806a: GSP optical counterpart detection DATE: 24/08/06 12:07:00 GMT FROM: Wenxiong Li <liwenxiong1992(a)gmail.com> W. X. Li, S. J. Xue (NAOC), M. Andrews, J. Farah, D. A. Howell, M. Newsome, E. Padilla Gonzalez, C. McCully, and G. Terreran (Las Cumbres Observatory), on behalf of a larger collaboration, report the optical follow-up observations of the fast X-ray transient EP240806a (Wu et al. 37063). An uncatalogued source is detected in the individual as well as the stacked frames within the EP/FXT error circle and localized at coordinates R.A. (J2000) = 11.4862 deg Dec. (J2000) = 5.0945 deg with an uncertainty of ~ 0.5 arcsec. The source has i ~ 21 mag, calibrated with SDSS and not corrected for Galactic extinction. There is no known object at the above position by checking MPC. We thus conclude that the source is the optical counterpart candidate of EP240806a. These observations were taken as part of the Global Supernova Project. View this GCN Circular online at https://gcn.nasa.gov/circulars/37064. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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