//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33570 SUBJECT: GRB 230405B: Fermi GBM Final Real-time Localization DATE: 23/04/05 20:08:29 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 19:58:03 UT on 5 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230405B (trigger 702417488.872428 / 230405832). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 276.9, Dec = -50.3 (J2000 degrees, equivalent to J2000 18h 27m, -50d 17'), with a statistical uncertainty of 1.6 degrees. The angle from the Fermi LAT boresight is 110.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405832/quicklook/glg_skymap_all_bn230405832.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405832/quicklook/glg_healpix_all_bn230405832.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405832/quicklook/glg_lc_medres34_bn230405832.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33571 SUBJECT: GRB 230405B: Swift detection of a burst DATE: 23/04/05 20:11:06 GMT FROM: David Palmer at LANL K. L. Page (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), M. J. Moss (GWU), D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 19:58:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230405B (trigger=1163119). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 271.467, -47.070 which is RA(J2000) = 18h 05m 52s Dec(J2000) = -47d 04' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 10 sec. The peak count rate was ~16000 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 19:59:09.2 UT, 65.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 271.44108, -47.06898 which is equivalent to: RA(J2000) = 18h 05m 45.86s Dec(J2000) = -47d 04' 08.3" with an uncertainty of 3.5 arcseconds (radius, 90% containment). This location is 63 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. No spectrum from the promptly downlinked event data is yet available to determine the column density. The initial flux in the 2.5 s image was 9.19e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 74 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. No correction has been made for the expected extinction corresponding to E(B-V) of 0.166. Burst Advocate for this burst is K. L. Page (kimlpage1978 AT gmail.com). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33572 SUBJECT: GRB 230405B: Prompt enhanced Swift-XRT position DATE: 23/04/05 20:37:19 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 230405B, we find an enhanced XRT position of the afterglow: RA, Dec: 271.44100, -47.06977 which is equivalent to: RA (J2000) = 18 05 45.84 Dec (J2000) = -47 04 11.2 with an uncertainty of 1.9 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/1163119. Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33573 SUBJECT: Swift GRB 230405B: Global MASTER-Net observations report DATE: 23/04/05 21:18:28 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 230405B ( K. L. Page et al., GCN 33571) errorbox 4283 sec after notice time and 4302 sec after trigger time at 2023-04-05 21:09:46 UT, with upper limit up to 16.0 mag. The observations began at zenith distance = 73 deg. The sun altitude is -56.4 deg. The galactic latitude b = -13 deg., longitude l = 346 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2208901 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 4393 | MASTER-SAAO | P\\ | 180 | 16.0 | 4393 | MASTER-SAAO | P/ | 180 | 16.0 | The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33574 SUBJECT: GRB 230405B: Enhanced Swift-XRT position DATE: 23/04/06 00:12:52 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1065 s of XRT Photon Counting mode data and 1 UVOT images for GRB 230405B, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 271.44062, -47.06983 which is equivalent to: RA (J2000): 18h 05m 45.75s Dec (J2000): -47d 04' 11.4" with an uncertainty of 2.2 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33575 SUBJECT: GRB 230405B: AstroSat CZTI detection DATE: 23/04/06 07:26:20 GMT FROM: Gaurav Waratkar at IIT,Bombay P K. Navaneeth (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 a long GRB 230405B which was also detected by Fermi (Fermi GBM Team, GCN 33570), and Swift (Page et al., GCN 33571). The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2023-04-05 19:58:05.65 UTC. The measured peak count rate associated with the burst is 894 (+200, -92) counts/s above the background in the combined data of three quadrants (out of four), with a total of 1098 (+189, -189) counts. The local mean background count rate was 336 (+8, -10) counts/s. Using cumulative rates, we measure a T90 of 4.3 (+1.0, -1.7) s. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-04-05 19:58:05.12 UTC. The measured peak count rate associated with the burst is 1564 (+88, -98) counts/s above the background in the combined data of all quadrants, with a total of 3078 (+369, -404) counts. The local mean background count rate was 1466 (+5, -6) counts/s. We measure a T90 of 4.1 (+5.1, -1.5) 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 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33576 SUBJECT: GRB 230405B: Swift/UVOT Upper Limits DATE: 23/04/06 08:06:53 GMT FROM: Samantha Oates at MSSL S. R. Oates (U. Birmingham) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 230405B 75 s after the BAT trigger (Page et al., GCN Circ. 33571). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 33574) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 75 224 147 >20.5 u_FC 287 537 246 >19.7 white 75 1363 373 >20.7 v 618 4860 274 >19.1 b 542 1339 78 >19.0 u 287 1313 304 >19.7 w1 668 1289 78 >18.5 m2 642 5065 274 >19.4 w2 593 1389 97 >18.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.166 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33582 SUBJECT: GRB 230405B: MeerLICHT upper limits DATE: 23/04/06 19:05:47 GMT FROM: Simon de Wet at UCT S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO), P.M. Vreeswijk (Radboud), D. Pieterse (Radboud) and D.B. Malesani (Radboud and DAWN/NBI) report on behalf of the MeerLICHT consortium: Following the detection of GRB 230405B by Swift/BAT along with its X-ray counterpart (Page et al., GCN 33571), the 0.6 m wide-field MeerLICHT optical telescope located at Sutherland, South Africa, obtained a repeated series of 60-s exposures in the q,u,g,r,i,z bands following the sequence quqgqrqiqz. Observations began 6.38 hours after the Swift trigger at 2023 April 6 02:20:05 UT and continued for a further 1.82 hours. Our individual 60-s exposures show no new optical source consistent with the enhanced XRT position (Beardmore et al., GCN 33574) when compared to archival DECam images of this field. We therefore co-added the images in each filter in order to obtain deeper limits. We report the following 3-sigma AB magnitude limits at the XRT position at ~7.2 hours post-trigger: u > 20.5 g > 21.3 q > 22.6 r > 21.2 i > 21.1 z > 20.1 MeerLICHT is built and run by a consortium consisting of Radboud University, University of Cape Town, the South African Astronomical Observatory, the University of Oxford, the University of Manchester and the University of Amsterdam. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33583 SUBJECT: GRB 230405B: Fermi GBM Observation DATE: 23/04/06 21:06:17 GMT FROM: Joshua Wood at MSFC/Fermi-GBM J. Wood (NASA/MSFC) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 19:58:03 UT on 05 April 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230405B (trigger 702417488/230405832). which was also detected by the Swift/BAT and Swift/XRT (K. L. Page et al. 2023, GCN 33571). The Fermi GBM on-ground location is consistent with the Swift XRT position. The angle from the Fermi LAT boresight is 105 degrees. The GBM light curve consists of a single pulse with a duration (T90) of about 4.3 s (50-300 keV). The time-averaged spectrum from T0+0.0 to T0+5.1 s is best fit by a Band function with Epeak = 225 +/- 11 keV, alpha = -0.53 +/- 0.05, and beta = -2.4 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (1.2 +/- 0.2)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.5 s in the 10-1000 keV band is 27.5 +/- 0.5 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/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33584 SUBJECT: GRB 230405B: Swift-XRT refined Analysis DATE: 23/04/07 02:01:14 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester) and K.L. Page report on behalf of the Swift-XRT team: We have analysed 6.5 ks of XRT data for GRB 230405B (Page et al. GCN Circ. 33571), from 54 s to 75.0 ks after the BAT trigger. The data comprise 246 s in Windowed Timing (WT) mode (the first 10 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 33572). The light curve can be modelled with an initial power-law decay with an index of alpha=0.88 (+/-0.04), followed by a break at T+937 s to an alpha of 1.14 (+0.16, -0.05). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.10 (+0.12, -0.11). The best-fitting absorption column is 4.0 (+0.6, -0.5) x 10^21 cm^-2, in excess of the Galactic value of 1.6 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.95 (+0.17, -0.16) and a best-fitting absorption column of 5.4 (+1.1, -1.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.2 x 10^-11 (6.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 5.4 (+1.1, -1.0) x 10^21 cm^-2 Galactic foreground: 1.6 x 10^21 cm^-2 Excess significance: 6.2 sigma Photon index: 1.95 (+0.17, -0.16) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01163119. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33585 SUBJECT: GRB 230405B: AGILE detection DATE: 23/04/07 08:42:42 GMT FROM: Claudio Casentini at INAF-IAPS C. Casentini, M. Cardillo (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS and Uni. Roma Tor Vergata), F. Lucarelli, F. Verrecchia(SSDC, and INAF/OAR), A. Argan, Y. Evangelista, L. Foffano, G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli, A. Di Piano, V. Fioretti, G.Panebianco, N. Parmiggiani (INAF/OAS-Bologna), M. Romani (INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen University), M. Pilia, A. Trois (INAF/OA Cagliari), I. Donnarumma, E. Menegoni, A.Ursi (ASI), A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio), report on behalf of the AGILE Team: The AGILE satellite detected the GRB 230405B at T0 = 2023-04-05 19:58:03 s (UTC), reported by Fermi (GCNs #33570, #33583), Swift (GCNs #33571, #33572, #33574, #33576, #33584), AstroSat CZTI (GCN #33575), MeerLICHT (GCN #33582), and Global MASTER-Net (GCN #33573). The burst is clearly visible in the AGILE scientific ratemeters of the MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 5 s and it released a total number of 3105 counts in the MCAL detector (above a background rate of 539 Hz), and 16691 counts in AC-Top detector (above a background rate of 2650 Hz). The AGILE ratemeters light curves can be found at http://www.agilescienceapp.it/notices/GRB230405B_AGILE_RM_ND.png . At the T0, the event was 83 deg off-axis. Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html Privo di virus.www.avast.com <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33586 SUBJECT: Konus-Wind detection of GRB 230405B DATE: 23/04/07 11:34:01 GMT FROM: Anna Ridnaia at Ioffe Institute A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 230405B (Fermi-GBM detection: The Fermi GBM team, GCN 33570; Wood & Meegan, GCN 33583; Swift-BAT detection: Page et al., GCN 33571; AstroSat CZTI detection: Navaneeth et al., GCN 33575; AGILE detection: Casentini et al., GCN 33585) triggered Konus-Wind at T0=71884.77 s UT (19:58:04.770). The burst light curve shows a single pulse, which starts at ~T0-6.1 s and has a total duration of ~10.7 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB230405_T71884/ As observed by Konus-Wind, the burst had a fluence of 2.24(-0.23,+0.27)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+1.088 s, of 9.76(-1.97,+2.26)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.37(-0.26,+0.30), the high energy photon index beta = -2.75(-0.64,+0.31), the peak energy Ep = 184(-20,+23) keV (chi2 = 101/91 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33590 SUBJECT: GRB 230405B: VZLUSAT-2 detection DATE: 23/04/07 21:07:07 GMT FROM: Marianna Dafcikova at Masaryk University <500025@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 230405B (Fermi/GBM detection: GCN 33570; Swift/BAT detection: GCN 33571; AstroSat detection: GCN 33575; AGILE detection: GCN 33585; Konus/Wind detection: GCN 33586; INTEGRAL/SPI-ACS detection at 2023-04-05 19:58:04) was detected by the GRB detector on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/). The data acquisition was performed by the GRB detector unit no. 1 and the detection was confirmed at the peak time 2023-04-05 19:58:04 UTC. The T90 duration was measured to be 3 s with the light curve resolution of 1 s. The significance during T90 reaches 25 sigma. The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/GRB230405B_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.