August 2023 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 32448] GRB 230827B: Swift ToO observations
by GCN Circulars 30 Aug '23

30 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34596 SUBJECT: GRB 230827B: Swift ToO observations DATE: 23/08/29 22:31:52 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Fermi/GBM GRB 230827B. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021620 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Fermi/GBM event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32447] LIGO/Virgo/KAGRA S230814ah: Updated Sky localization
by GCN Circulars 29 Aug '23

29 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34595 SUBJECT: LIGO/Virgo/KAGRA S230814ah: Updated Sky localization DATE: 23/08/29 21:57:07 GMT FROM: Charlie Hoy at University of Portsmouth <charlie.hoy(a)port.ac.uk> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S230814ah (GCN Circular 34429). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.offline0.multiorder.fits, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S230814ah For the Bilby.offline0.multiorder.fits sky map, the 90% credible region is 25260 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 330 +/- 105 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/userguide/. [1] Ashton et al. ApJS 241, 27 (2019) --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32446] GRB 230827A: Fermi GBM Observation
by GCN Circulars 29 Aug '23

29 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34594 SUBJECT: GRB 230827A: Fermi GBM Observation DATE: 23/08/29 18:29:51 GMT FROM: Lorenzo Scotton at UAH <lscottongcn(a)outlook.com> L. Scotton (UAH), C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 18:17:52.93 UT on 27 August 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230827A (trigger 714853077/230827762). which was also detected by GRBAlpha (Dafcikova et al. 2023, GCN 34583) and Swift/BAT GUANO (DeLaunay et al. 2023, GCN 34587). The Fermi GBM Final Real-time Localization was reported in GCN 34575. The angle from the Fermi LAT boresight is 95 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 83 s (50-300 keV). The time-averaged spectrum from T0-1.2 to T0+85.9 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.96 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 415 +/- 26 keV. The event fluence (10-1000 keV) in this time interval is (3.58 +/- 0.08)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+21 s in the 10-1000 keV band is 10.7 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32445] GRB 230827B: CALET Gamma-Ray Burst Monitor detection
by GCN Circulars 29 Aug '23

29 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34593 SUBJECT: GRB 230827B: CALET Gamma-Ray Burst Monitor detection DATE: 23/08/29 15:56:27 GMT FROM: Yuta Kawakubo at Louisiana State University <kawakubo1(a)lsu.edu> T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long GRB 230827B (Fermi GBM Observation: Hamburg et al., GCN Circ. 34584; VZLUSAT-2 detection: Dafcikova et al., GCN Circ. 34585) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 06:08:28.36 UTC on 27 July 2023 (http://cgbm.calet.jp/cgbm_trigger/flight/1377151581/). The burst signal was seen by only the SGM detector. The burst light curve shows a multi-peaked structure that starts at T+2.3 sec, peaks at T+2.7 sec, and ends at T+87.7 sec. The T90 and T50 durations measured by the SGM data are 79.6 +/- 3.7 sec and 57.4 +/- 2.5 sec (40-1000 keV), respectively. The ground-processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1377151581/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32444] GRB 230826A: Swift-BAT refined analysis
by GCN Circulars 29 Aug '23

29 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34592 SUBJECT: GRB 230826A: Swift-BAT refined analysis DATE: 23/08/29 15:27:50 GMT FROM: Tyler Parsotan at NASA GSFC <tyler.parsotan(a)nasa.gov> D. M. Palmer (LANL), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+1091 sec from the recent telemetry downlink, we report further analysis of BAT GRB 230826A (trigger #1187463) (Eyles-Ferris, et al., GCN Circ. 34565). The BAT ground-calculated position is RA, Dec = 83.048, 66.129 deg which is RA(J2000) = 05h 32m 11.5s Dec(J2000) = +66d 07' 43.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 87%. The mask weighted light curve shows two main emission episodes where the first has enhanced structure. T90 (15-350 keV) is 41.07 +- 2.36 sec (estimated error including systematics). The time-averaged spectrum from T-4.26 to T+56.79 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.20 +- 0.22, and Epeak of 122.3 +- 70.2 keV (chi squared 44.78 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.6 +- 0.1 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+2.44 sec in the 15-150 keV band is 3.0 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.55 +- 0.05 (chi squared 52.29 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1187463/BA/ <http://gcn.gsfc.nasa.gov/notices_s/1187463/BA/> --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32443] GRB 230828A: AstroSat CZTI detection
by GCN Circulars 29 Aug '23

29 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34591 SUBJECT: GRB 230828A: AstroSat CZTI detection DATE: 23/08/29 12:00:17 GMT FROM: Gaurav Waratkar at IIT Bombay <gauravwaratkar(a)iitb.ac.in> P. K. Navaneeth (IUCAA), G. Waratkar (IITB), B. Pari (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 230828A which was also detected by GRBAlpha (Dafcikova et al., GCN Circ. 34590). The source was clearly detected in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2023-08-28 16:28:57.50 UTC. The measured peak count rate associated with the burst is 152 (+47, -8) counts/s above the background in the combined data of all quadrants, with a total of 4190 (+848, -887) counts. The local mean background count rate was 434 (+2, -2) counts/s. Using cumulative rates, we measure a T90 of 142 (+18, -22) s. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2023-08-28 16:29:43.14 UTC. The measured peak count rate associated with the burst is 410 (+75, -17) counts/s above the background in the combined data of all quadrants, with a total of 10117 (+1492, -1750) counts. The local mean background count rate was 1341 (+3, -4) counts/s. We measure a T90 of 123 (+10, -6) 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 --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32442] GRB 230828A: GRBAlpha detection
by GCN Circulars 29 Aug '23

29 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34590 SUBJECT: GRB 230828A: GRBAlpha detection DATE: 23/08/29 11:14:43 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), yyT. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 230828A (AstroSat trigger at 2023-08-28 16:29:43 UT, INTEGRAL/SPI-ACS detection at 2023-08-28 ~16:28:55 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023; arXiv:2302.10048). The detection was confirmed at the peak time 2023-08-28 16:29:53 UTC. The T90 duration measured by GRBAlpha is 140 s and the overall significance during T90 reaches 27 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB230828A_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32441] Swift Trigger 1188089 is not a GRB
by GCN Circulars 29 Aug '23

29 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34589 SUBJECT: Swift Trigger 1188089 is not a GRB DATE: 23/08/29 06:38:32 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> S. Dichiara (PSU) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: Swift Trigger 1188089 (2023-08-29 06:12:48 UT) is not an astrophysical event. It is a spurious trigger due to a misidentification of the Crab during a star tracker Loss-of-Lock event. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32440] GRB 230827A: VZLUSAT-2 detection
by GCN Circulars 28 Aug '23

28 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34588 SUBJECT: GRB 230827A: VZLUSAT-2 detection DATE: 23/08/28 20:31:23 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), 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 230827A (Fermi/GBM detection: GCN 34575; GRBAlpha detection: GCN 34583; Swift/BAT-GUANO detection: GCN 34587; INTEGRAL/SPI-ACS detection at 2023-08-27 ~18:17:53 UT) 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 2023-08-27 18:18:09 (18:18:18) UTC. The T90 duration is 82 s (77 s) and the significance during T90 reaches 10 sigma (24 sigma) for detector unit no. 0 (no. 1). The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB230827A_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. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 32439] GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
by GCN Circulars 28 Aug '23

28 Aug '23

TITLE: GCN CIRCULAR NUMBER: 34587 SUBJECT: GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV DATE: 23/08/28 19:25:30 GMT FROM: Jimmy DeLaunay at University of Alabama <delauj2(a)gmail.com> James DeLaunay (U Alabama), Aaron Tohuvavohu (U Toronto), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 230827A onboard (T0: 2023-08-27T18:17:52.93 UTC, Fermi trig 714853077) The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 90 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 54.6 in a 8.192 s analysis time bin, starting at T0 + 18.432 s. NITRATES results are consistent with a burst coming from outside the FOV, with DeltaLLHOut of -61 and are consistent with Fermi GBM's localization (GCN 34575). See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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