GRB230911C

This page lists all entries on GRB230911C in GRBweb

Summary IPN Swift GCN 34655 GCN 34662 GCN 34665 GCN 34667 GCN 34671 GCN 34673 GCN 34675 GCN 34676 GCN 34843

Summary table
Variable Value Source
T0 8:47:25 UTC GCN_circulars,Swift Det
ra 226.7980° Swift
decl -41.3297° Swift
pos_error 5.44e-04° Swift
GBM_located False
mjd 60198.366261574076 GCN_circulars,Swift Det
IPN table
GRB_name GRB230911C
ra 226.7833°
decl -41.3333°
pos_error 5.00e-02°
Swift table
GRB_name GRB230911C
t_trigger 8:47:25 UTC
ra 226.7980°
decl -41.3297°
pos_error 5.44e-04°
GCN 34655 table
GRB_name GRB230911C
GCN_number 34655
Detection_method Swift Det
t_trigger 8:47:25 UTC
ra 226.7820°
decl -41.3340°
Circular_text TITLE: GCN CIRCULAR NUMBER: 34655 SUBJECT: GRB 230911C: Swift detection of a burst DATE: 23/09/11 09:11:10 GMT FROM: K.L. Page at U Leicester E. Sonbas (Adiyaman Univ.), R. Brivio (INAF-OAB), S. Dichiara (PSU), M. Ferro (INAF-OAB), J.D. Gropp (PSU), A. Y. Lien (U Tampa), A. Melandri (INAF-OAR), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), C. Salvaggio (INAF-OAB) and T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team: At 08:47:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230911C (trigger=1191188). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 226.782, -41.334 which is RA(J2000) = 15h 07m 08s Dec(J2000) = -41d 20' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 10 sec. The peak count rate was ~700 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 08:49:24.4 UT, 119.0 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 226.79804, -41.32973 which is equivalent to: RA(J2000) = 15h 07m 11.53s Dec(J2000) = -41d 19' 47.0" with an uncertainty of 4.2 arcseconds (radius, 90% containment). This location is 46 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (9.36 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 4 (+3.90/-3.22) x 10^21 cm^-2 (90% confidence). Processed UVOT data were not available at low latency, with the images affected by the attitude issues reported in GCN Circ. 34633. Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.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/)
GCN 34662 table
GRB_name GRB230911C
GCN_number 34662
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 34662 SUBJECT: GRB 230911C: GOTO optical upper limits DATE: 23/09/11 16:16:25 GMT FROM: Amit Kumar at University of Warwick, UK D. O’Neill; A. Kumar; B. P. Gompertz; K. Ulaczyk; G. Ramsay; R. Starling; K. Ackley; M. J. Dyer; J. Lyman; F. Jiminez-Ibarra; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration: We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to GRB 230911C (Sonbas et al., GCN 34655). Three targeted observations were performed by GOTO-South, located at Siding Spring Observatory, between 08:52:42 UT and 09:14:52 UT on 2023-09-11 (5.28, 16.08 and 27.47 minutes after trigger). Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm). Images were processed immediately after acquisition using the GOTO pipeline. We identify no candidate optical counterparts within the enhanced XRT localisation region (Evans et al., GCN 34658). The 5-sigma limiting magnitudes were 20.7, 20.4 and 21.0 mag, respectively. GOTO (https://goto-observatory.org) is a network of telescopes operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC). We note that this is the first scientific contribution from GOTO-South.
GCN 34665 table
GRB_name GRB230911C
GCN_number 34665
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 34665 SUBJECT: GRB 230911C: Swift/UVOT Upper Limits DATE: 23/09/11 20:49:01 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and E. Sonbas (Adiyaman Univ.) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 230911C 122 s after the BAT trigger (Sonbas et al., GCN Circ. 34655). No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 34658) 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 122 272 147 >20.4 white 122 4926 289 >21.0 u_FC 280 530 246 >19.7 u 280 4572 708 >20.2 b 537 4778 235 >19.8 w1 661 4368 216 >19.0 w2 587 781 39 >18.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.101 in the direction of the burst (Schlegel et al. 1998).
GCN 34667 table
GRB_name GRB230911C
GCN_number 34667
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 34667 SUBJECT: GRB230911C: LCOGT Optical Upper Limits DATE: 23/09/11 20:58:29 GMT FROM: Robert Strausbaugh at Eastern Illinois University R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the Swift GRB 230911C (Sonbas et al., GCN 34655) field with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on September 11, from 17:20 to 17:52 UT (corresponding to 8.55 to 9.08 hours from the GRB trigger time) with the SDSS r and i filters. We performed a series of 3x300s exposures in each band. We do not detect a source within the Swift-XRT enhanced error region (Evans et al., GCN 34658) in either band. The following upper limits are calculated using the USNO-B1.0 catalog as reference: r > 21.6 i > 21.1 These magnitudes are not corrected for galactic extinction.
GCN 34671 table
GRB_name GRB230911C
GCN_number 34671
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 34671 SUBJECT: Swift GRB 230911C: Global MASTER-Net observations report DATE: 23/09/11 23:34:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (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. Gress, N.M. Budnev, O.Ershova (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), V. Yurkov, A. Gabovich (Blagoveschensk Educational State University) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 230911C ( E. Sonbas et al., GCN 34655) errorbox 51970 sec after notice time and 52039 sec after trigger time at 2023-09-11 23:14:45 UT, with upper limit up to 17.3 mag. Observations started at twilight. The observations began at zenith distance = 37 deg. The sun altitude is -11.6 deg. The galactic latitude b = 14 deg., longitude l = 329 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2268945 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 52130 | MASTER-OAFA | C | 180 | 16.3 | 52362 | MASTER-OAFA | C | 180 | 16.5 | 52795 | MASTER-OAFA | C | 180 | 17.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 34673 table
GRB_name GRB230911C
GCN_number 34673
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 34673 SUBJECT: GRB230911C: BOOTES-6/DPRT optical upper limit DATE: 23/09/12 01:31:57 GMT FROM: Youdong HU at IAA-CSIC E. Fernandez-Garcia, Y.-D. Hu, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland) and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report: Following the detection of GRB 230911C by Swift (Sonbas et al. GCNC 34655), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) automatically observed the GRB location starting on Sep. 11, 17:26 UT (~ 8.7 h after trigger). No new optical source is detected on the co-added images (3 x 60 s, i-filter & 3 x 60 s, Z-filter) within the enhanced Swift/XRT error region (Evans et al. GCNC 34658) down to 19.2 mag and 18.5 mag respectively, which are consistent with reports from GOTO (O'Neill et al. GCNC 34662), UVOT (Breeveld et al. GCNC 34665), LCOGT (Strausbaugh et al. GCNC 34667) and MASTER (Lipunov et al. GCNC 34671). We thank the staff at Boyden Observatory for their excellent support.
GCN 34675 table
GRB_name GRB230911C
GCN_number 34675
Detection_method Swift-BAT Det
ra 226.7960°
decl -41.3560°
Circular_text TITLE: GCN CIRCULAR NUMBER: 34675 SUBJECT: GRB 230911C: Swift-BAT refined analysis DATE: 23/09/12 03:07:59 GMT FROM: Amy T. Sakamoto (AGU), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), E. Sonbas (Adiyaman Univ.), M. Stamatikos (OSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 230911C (trigger #1191188) (Sonbas et al., GCN Circ. 34655). The BAT ground-calculated position is RA, Dec = 226.796, -41.356 deg which is RA(J2000) = 15h 07m 11.0s Dec(J2000) = -41d 21' 21.2" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 95%. The mask-weighted light curve shows multiple weak overlapping pulses that start at ~T-9 s and end at ~T+10 s. T90 (15-350 keV) is 16.21 +- 2.89 sec (estimated error including systematics). The time-averaged spectrum from T-8.63 to T+9.58 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.28. The fluence in the 15-150 keV band is 3.8 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+2.07 sec in the 15-150 keV band is 0.7 +- 0.2 ph/cm2/sec. 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/1191188/BA/
GCN 34676 table
GRB_name GRB230911C
GCN_number 34676
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 34676 SUBJECT: GRB 230911C: Swift-XRT refined Analysis DATE: 23/09/12 11:45:52 GMT FROM: Phil Evans at U of Leicester A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 7.2 ks of XRT data for GRB 230911C, from 103 s to 74.1 ks after the BAT trigger. The data comprise 106 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+4.2 ks) can be modelled with a power-law decay with a decay index of alpha=0.48 (+0.22, -0.18). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.86 (+0.26, -0.21). The best-fitting absorption column is 1.3 (+0.9, -0.3) x 10^21 cm^-2, consistent with the Galactic value of 9.4 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.3 (+0.9, -0.3) x 10^21 cm^-2 Galactic foreground: 9.4 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.86 (+0.26, -0.21) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01191188. This circular is an official product of the Swift-XRT team.
GCN 34843 table
GRB_name GRB230911C
GCN_number 34843
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 34843 SUBJECT: GRB 230911C: ATCA detection of possible radio counterpart DATE: 23/10/19 17:29:14 GMT FROM: Sarah Chastain at University of New Mexico S. Chastain (UNM), G. E. Anderson (Curtin), J. K. Leung (UofT/HUJI), S. D. Ryder (Macquarie), A. J. van der Horst (GWU), A. Gulati (USyd), and L. Rhodes (Oxford) on behalf of the ATCA PanRadio GRB collaboration The Australia Telescope Compact Array (ATCA) observed long GRB 230911C (E. Sonbas et al., GCN 34655) as part of the ATCA "PanRadio GRB" Large Project C3542 (PI: G. Anderson) on 2023-09-11 UT, 2023-09-13 UT, 2023-09-26 UT, and 2023-10-16 UT. We detect a possible radio afterglow at 9 GHz in the second epoch, which continues to brighten in the third, and fourth epoch. At 5.5 GHz this source is not detected in any of the observations. In the fourth epoch at 5.5 GHz, we find 3-sigma upper limit of 105 microJy/beam. In the fourth epoch at 9.0 GHz, the source detected in the previous observations is detected at 150 +/- 35 microJy/beam. The fitted position is: RAJ2000 = 15:07:13 +/- 8 arcseconds DECJ2000 = -41:19:51 +/- 1 arcsecond This is approximately 18 arcseconds away from the reported Swift/XRT enhanced position (P. A. Evans et al., GCN 34658). Further observations are planned. We thank the CSIRO Space and Astronomy staff for supporting these observations. We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.