GRB180914B

This page lists all entries on GRB180914B in GRBweb

Summary IPN GCN 23226 GCN 23231 GCN 23232 GCN 23233 GCN 23234 GCN 23236 GCN 23237 GCN 23238 GCN 23239 GCN 23240 GCN 23241 GCN 23242 GCN 23243 GCN 23244 GCN 23245 GCN 23246 GCN 23249 GCN 23250 GCN 23251 GCN 23252 GCN 23253 GCN 23255 GCN 23256 GCN 23278 GCN 23287 GCN 23288

Summary table
Variable Value Source
T0 18:23:02 UTC GCN_circulars,Fermi LAT Det
ra 332.4500° IPN
decl 24.8833° IPN
pos_error 3.33e-01° IPN
redshift 1.0960 GCN_circulars,Konus-Wind Det
GBM_located False
mjd 58375.76599537037 GCN_circulars,Fermi LAT Det
IPN table
GRB_name GRB180914B
ra 332.4500°
decl 24.8833°
pos_error 3.33e-01°
redshift 1.0960
GCN 23226 table
GRB_name GRB180914B
GCN_number 23226
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23226 SUBJECT: GRB 180914B: AGILE/MCAL detection of a burst DATE: 18/09/14 22:37:55 GMT FROM: Alessandro Ursi at INAF/IAPS GRB 180914B: AGILE/MCAL detection of a burst A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, Y. Evangelista, G. Minervini, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS), M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE Mini-CALorimeter (MCAL) detected a long burst at T0 = 2018-09-14 18:23:02.22 +/- 0.01 s (UTC). The event lasted T90 = 5.8 s (in the 0.4-100 MeV energy range), consisting of two broad pulses, and released a total number of ~25,000 counts in the detector, above an average background rate of ~1250 counts / s. Further analysis is still in progress. The AGILE-MCAL detector has a full solid angle acceptance, and is operational in the range 0.4 - 100 MeV.
GCN 23231 table
GRB_name GRB180914B
GCN_number 23231
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23231 SUBJECT: GRB 180914B: AGILE/GRID detection DATE: 18/09/15 14:06:01 GMT FROM: Alessandro Ursi at INAF/IAPS GRB 180914B: AGILE/GRID detection F. Verrecchia (SSDC, and INAF/OAR), A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Longo (Univ. Trieste and INFN Trieste), A. Argan, M. Cardillo, A. Giuliani (INAF/IASF-Mi), Y. Evangelista, G. Minervini, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino, M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), report on behalf of the AGILE Team: The Gamma-Ray Imaging Detector (GRID) of AGILE detected the long bright GRB 180914B reported Ursi et al., GCN 23226. A preliminary GRID analysis in the energy range 30 - 420 MeV shows a detection with a statistical significance of about 9 sigma, at the sky position L,B: 85,-26 +/- 5 deg. The gamma-ray emission detected by the AGILE-GRID lasted about 16 seconds, and the preliminary estimated position is between 50 and 70 deg off-axis angle. These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress.
GCN 23232 table
GRB_name GRB180914B
GCN_number 23232
Detection_method Fermi LAT Det
t_trigger 18:23:02 UTC
ra 332.4500°
decl 24.8800°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23232 SUBJECT: GRB 180914B: Fermi-LAT detection DATE: 18/09/15 14:32:01 GMT FROM: Elisabetta Bissaldi at INFN,Bari E. Bissaldi (Politecnico & INFN Bari) and F. Longo (Univ & INFN Trieste) report on behalf of the Fermi-LAT team: At 18:23:02 UT on September 14, 2018 Fermi-LAT detected high-energy emission from GRB 180914B, which was also detected by AGILE/MCAL (Ursi et al., GCN #23226) and by AGILE/GRID (Verrecchia et al., GCN #23231). The best LAT on-ground location is found to be RA, Dec = 332.45, 24.88 (J2000) with an error radius of 0.33 deg (90 % containment, statistical error only). This was 94 deg from the LAT boresight at the time of the trigger. The Fermi-LAT position is consistent with the AGILE/GRID one. The data from the Fermi-LAT show a significant increase in the event rate that is spatially correlated with the trigger with high significance. The highest-energy photon is a 12.6 GeV event which is observed 1662 s after the AGILE trigger. A Swift ToO has been requested for this burst. The Fermi-LAT point of contact for this burst is Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it). The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN 23233 table
GRB_name GRB180914B
GCN_number 23233
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23233 SUBJECT: GRB 180914B: AGILE/GRID detection DATE: 18/09/15 14:51:10 GMT FROM: Francesco Verrecchia at ASDC F. Verrecchia (SSDC, and INAF/OAR), A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Longo (Univ. Trieste and INFN Trieste), A. Argan, M. Cardillo, A. Giuliani (INAF/IASF-Mi), Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori, A. Bulgarelli, V. Fioretti, F. Fuschino, M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), report on behalf of the AGILE Team: The Gamma-Ray Imaging Detector (GRID) of AGILE detected the long bright GRB 180914B reported in Ursi et al., GCN 23226. A preliminary GRID analysis in the energy range 30 - 420 MeV shows a detection with a statistical significance of about 9 sigma, at the sky position L,B: 85.0, -26.0 +/- 5 deg. The gamma-ray emission detected by the AGILE-GRID lasted about 16 seconds, and the preliminary estimated position is between 50 and 70 deg off-axis. These measurements were obtained with AGILE observing a large portion of the sky in spinning mode. Additional analysis of AGILE data is in progress.
GCN 23234 table
GRB_name GRB180914B
GCN_number 23234
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23234 SUBJECT: GRB 180914B: Tiled Swift observations DATE: 18/09/15 17:34:21 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the Fermi/LAT GRB 180914B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00075 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/LAT event is high: 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.
GCN 23236 table
GRB_name GRB180914B
GCN_number 23236
Detection_method Swift-XRT Other
ra 332.3565°
decl 25.0631°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23236 SUBJECT: GRB 180914B: Swift-XRT afterglow detection DATE: 18/09/15 22:21:41 GMT FROM: Paolo D'Avanzo at INAF-OAB A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/LAT-detected burst GRB 180914B (Bissaldi et al. GCN Circ. 23232) in a series of observations tiled on the sky. The total exposure time is 4.1 ks, distributed over 6 tiles; the maximum exposure at a single sky location was 1.3 ks. The data were collected between T0+82.8 ks and T0+93.8 ks, and are entirely in Photon Counting (PC) mode. An uncatalogued X-ray source is detected and is above the RASS limit, and is therefore likely the GRB afterglow. Using 579 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 332.35648, +25.06314 which is equivalent to: RA (J2000): 22h 09m 25.56s Dec(J2000): +25d 03' 47.3" with an uncertainty of 3.4 arcsec (radius, 90% confidence). This position is 12.1 arcmin from the Fermi/LAT position. The source has a mean count rate of 6.2e-02 ct/sec; we cannot determine at the present time whether it is fading. The results of the XRT-team automatic analysis of the likely afterglow are at http://www.swift.ac.uk/xrt_products/TILED_GRB00075/Source2.php. The results of the full analysis of the tiled XRT observations are available at http://www.swift.ac.uk/xrt_products/TILED_GRB00075. This circular is an official product of the Swift-XRT team.
GCN 23237 table
GRB_name GRB180914B
GCN_number 23237
Detection_method Swift-XRT Other
ra 332.3565°
decl 25.0622°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23237 SUBJECT: GRB 180914B: KAIT Optical Afterglow Candidate DATE: 18/09/16 04:23:18 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to AGILE/MCAL GRB 180914B (Ursi et al., GCN 23226 starting at Sep. 16, 03:47:39 UT, namely ~1.392 days after the burst. Observations were performed with a sequence in the clear (roughly R), B, V, R, and I filters, and the exposure time was 60 s per image. Inside the reported Swift/XRT afterglow error circle (D'Ai et al., GCN 23236) we detected an optical afterglow candidate at position: RA: 22:09:25.55 (J2000) Dec: +25:03:43.90 (J2000) We estimate the clear band magnitude ~19.2. At this time, we can not estimate the changes of the brightness. But the object was not presented in the SDSS image, we therefore suggest it to be the optical afterglow of GRB 180914B. Observation are on going, multi-band follow-ups are encouraged.
GCN 23238 table
GRB_name GRB180914B
GCN_number 23238
Detection_method Swift-XRT Other
redshift 0.5800
Circular_text TITLE: GCN CIRCULAR NUMBER: 23238 SUBJECT: GRB 180914B: RATIR Optical and NIR Observations DATE: 18/09/16 05:48:12 GMT FROM: Eleonora Troja at GSFC Eleonora Troja (GSFC), Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), , Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesus Gonzalez (UNAM), Carlos Roman-Zuniga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 180914B, detected by AGILE/MCAL (Ursi, et al., GCN 23226) AGILE/GRID (Verrecchia, et al., GCN 23231), and Fermi/LAT (Bissaldi, et al., GCN 23232) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronomico Nacional on Sierra San Pedro Martir from 2018/09 16.14 to 2018/09 16.16 UTC (32.90 to 33.43 hours after the burst), obtaining 0.36 hours exposure in the r and i bands and 0.15 hours exposure in the Z, Y, J, and H bands. Within the Swift-XRT error circle (D'Ai, et al., GCN 23236), we detect the object reported by Zheng & Filippenko (GCN 23237). In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections: r = 19.51 +/- 0.01 i = 19.20 +/- 0.01 z = 18.93 +/- 0.03 Y = 18.75 +/- 0.03 J = 18.60 +/- 0.05 H = 18.28 +/- 0.04 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source position is consistent with a catalogued SDSS galaxy with photometric redshift z~0.58. However, its brightness is significantly higher than the values reported in the catalogue,suggesting that the emission may be dominated by the GRB afterglow and that the SDSS object may be the GRB host galaxy. Further observations to establish the source variability are planned. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.
GCN 23239 table
GRB_name GRB180914B
GCN_number 23239
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23239 SUBJECT: GRB 180914B: Optical counterpart observation from OAJ DATE: 18/09/16 08:58:16 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), L. Izzo (HETH/IAA-CSIC), D.A. Kann (HETH/IAA-CSIC), C.C. Thoene (HETH/IAA-CSIC), H. Vazquez Ramio (CEFCA), N. Maicas (CEFCA) and V. Tilve (CEFCA) report: We have observed the field of GRB 180914B (Ursi et al., GCN 23226; Verrecchia et al., GCN 23231; Bissaldi et al. GCN 23232; D’Ai et al., GCN 23236) with the 0.8m T80 telescope of the Javalambre Astrophysical Observatory (Teruel, Spain). The observation consisted of 12x300s i-band exposures, each covering the complete LAT error box. The exposures started at 22:03:46 UT of the 15th September, 27.68 hr after the burst. The counterpart identified by Zheng & Filippenko (GCN 23237) and Troja et al. (GCN 23238) is well detected in the individual images. Photometry of the first epoch, as compared with SDSS reference stars yields i(AB)=18.84+/-0.03. Comparing with the RATIR photometry (roja et al. GCN 23238), our photometry implies a decay rate of alpha ~ -1.9 (where F_nu ~ t^alpha), indicating that the afterglow has possibly entered a post-jet-break regime evolution.
GCN 23240 table
GRB_name GRB180914B
GCN_number 23240
Detection_method Konus-Wind Det
t_trigger 18:23:02.692 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 23240 SUBJECT: Konus-Wind of the very bright GRB 180914B DATE: 18/09/16 14:34:47 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long, very bright GRB 180914B (Agile/MCAL detection: Ursi et al., GCN 23226; Fermi-LAT detection: Bissaldi & Longo, GCN 23232, Agile/GRID detection: Verrecchia et al., GCN 23233) triggered Konus-Wind (KW) at T0=66182.692 s UT (18:23:02.692). The burst light curve shows multiple pulses in the interval from T0 - 30 s to T0+250 s. A total duration of the burst (T100) is ~280 s. The emission is seen up to ~15 MeV. As observed by Konus-Wind, the burst had a fluence of (1.15 ± 0.05)x10^-3 erg/cm2 and a 64-ms peak energy flux, measured from T0+5.824, of (1.14 ± 0.24)x10^-4 erg/cm2 (both in the 20 keV - 10 MeV energy range). The fluence of GRB 180914B is among the highest measured for the Konus-Wind sample of >3000 GRBs detected since 1994. The time-integrated spectrum (measured from T0 to T0+168.192 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.81 (-0.04,+0.04), the high energy photon index beta = -2.12 (-0.7,+0.08), the peak energy Ep = 466 (-27,+29) keV (chi2 = 104/97 dof). The spectrum near the peak count rate (measured from T0+5.632 s to T0+6.144 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: alpha = -0.64 (-0.08,+0.10), beta = -1.98 (-0.16,+0.12), Ep = 1285 (-249,+287) keV (chi2 = 68/69 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB180914_T66182/ All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.
GCN 23241 table
GRB_name GRB180914B
GCN_number 23241
Detection_method Swift-UVOT Det
ra 332.2609°
decl 24.5823°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23241 SUBJECT: GRB180914B: Swift UVOT detection of an optical afterglow DATE: 18/09/16 16:05:06 GMT FROM: Paul Kuin at MSSL N. Paul M. Kuin reports on behalf of the Swift-UVOT team: Swift-UVOT has performed follow-up observations of the Fermi/LAT-detected burst GRB 180914B (Bissaldi et al. GCN Circ. 23232) in a series of observations tiled on the sky. Within the error of the location of the XRT source (D'Ai, GCN Circ. 23236) we detect a source that appears to be fading. The UVOT source location is RA = 332.2609, Dec = 24.5823 deg which is RA = 22:09:25.53 (J2000) Dec = +25:03:43.8 (J2000) which is consistent with Zheng and Filipenko (GCN Circ. 23237). The preliminary magnitude using the UVOT photometric calibration (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) is filter Tstart Tend exposure magnitude u 8.35e4 8.37e4 76.5 18.90 +- 0.23 u 8.70e4 8.74e4 373.0 18.87 +- 0.11 u 9.27e4 9.29e4 1.93.8 19.05 +- 0.17A Times in seconds since Tzero=2018-09-14 18:22:40 UT. No correction has been made for Galactic interstellar reddening of E(B-V) = 0.07 (Schlafy&Finkbeiner, 2011 ApJ 737, 103).
GCN 23242 table
GRB_name GRB180914B
GCN_number 23242
Detection_method Konus-Wind Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 23242 SUBJECT: GRB 180914B: AGILE/MCAL refined analysis DATE: 18/09/16 18:26:38 GMT FROM: Alessandro Ursi at INAF/IAPS GRB 180914B: AGILE/MCAL refined analysis A. Ursi (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), F. Longo (Univ. Trieste and INFN Trieste), A. Argan, M. Cardillo, Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS), M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: We present a refined analysis of the long GRB 180914B detected by AGILE/MCAL (Ursi et al., GCN #23226), AGILE/GRID (Verrecchia et al., GCN #23231), Fermi/LAT (Bissaldi et al., GCN #23232), and Konus-Wind (Frederiks et al., GCN #23240), whose afterglow has been so far detected by Swift/XRT (D'Ai et al., GCN #23236) and Swift/UVOT (Kuin et al., GCN #23241), KAIT (Zheng & Filippenko, GCN #23237), RATIR (Troja et al., GCN #23238), and OAJ (de Ugarte Postigo et al., GCN #23239). The AGILE Mini-CALorimeter (MCAL) detector high time resolution data acquisition was triggered twice by the GRB on sub-millisecond and 16 ms timescales. A first GRB peak triggered complete MCAL data acquisition, starting at T1 = 2018-09-14 18:23:02.22 +/- 0.01 s (UTC) and ending at about T1+6.4 s, and lasted the whole duration of the acquisition. The time-integrated spectrum measured between T1 and T1+6.4 s can be fitted in the energy range 0.5-40 MeV with a power law with photon index 1.74 -0.13/+0.06 and a cut-off energy of 2.35 -2.2/+1.54 MeV, with a reduced chi-square of 1.13 (66 d.o.f.). The burst fluence in the same energy range and time interval is 2.4e-04 erg/cm^2 (90% confidence level). After ~85 s, a second GRB peak triggered complete MCAL data acquisition, starting at T2 = 2018-09-14 18:24:27.84 +/- 0.01 s and ending at about T2+6.4, and lasted about 2.7 s. The time-integrated spectrum measured between T2 and T2+2.7 s can be fitted in the 0.5-40 MeV energy range with a simple power law with ph.ind. = 2.13 -0.07/+0.08 and a reduced chi-square of 1.23 (68 d.o.f.). The corresponding fluence is 1.94e-05 erg/cm^2 (90% confidence level). The AGILE-MCAL detector has a full solid angle acceptance, and is operational in the range 0.4 - 100 MeV. This observation was done with the MCAL trigger capability set to a reduced mode with substantial TM constraints, and the Super-AGILE imaging being turned-off. A substantially enhanced AGILE instrument configuration is foreseen to be implemented shortly.
GCN 23243 table
GRB_name GRB180914B
GCN_number 23243
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23243 SUBJECT: GRB 180914B: Continued RATIR Optical and NIR Observations DATE: 18/09/17 07:20:02 GMT FROM: Eleonora Troja at GSFC Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), , Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesus Gonzalez (UNAM), Carlos Roman-Zuniga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We re-observed the field of GRB 180914B (Ursi, et al., GCN 23226) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronomico Nacional on Sierra San Pedro Martir from 2018/09 17.12 to 2018/09 17.28 UTC (56.53 to 60.22 hours after the burst), obtaining a total of 2.49 hours exposure in the r and i bands and 1.04 hours exposure in the Z, Y, J, and H bands. At the position of the optical/nIR counterpart (Zheng & Filippenko, GCN 23237; Troja, et al., GCN 23238), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections: r = 20.46 +/- 0.01 i = 20.08 +/- 0.01 z = 19.74 +/- 0.02 Y = 19.57 +/- 0.02 J = 19.33 +/- 0.02 H = 19.08 +/- 0.03 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Compared to our first night of observations (Troja, et al., GCN 23238), the source significantly faded at an approximate decay rate of t^(-1.4), shallower than the value found by De Ugarte Postigo, et al. (GCN 23239) at earlier times. Further observations are planned. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.
GCN 23244 table
GRB_name GRB180914B
GCN_number 23244
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23244 SUBJECT: GRB 180914B : TSHAO optical observations DATE: 18/09/17 10:26:49 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Pozanenko (IKI), I. Reva (FAPHI), A. Kusakin (FAPHI), A. Volnova (IKI), M. Krugov (FAPHI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 180914B (Ursi, et al., GCN 23226; Bissaldi et al., GCN 23232; Frederiks et al., GCN 23240) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on September 16 (UT) 19:44:34, obtaining a total of 46.5 minutes exposure in the Rc-band. Within XRT position (D'Ai et al., GCN 23236) we detect the object reported by Zheng & Filippenko (GCN 23237), Troja et al. (GCN 23238), (Paul & Kuin, GCN 23241). Preliminary photometry of the objext is following. Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2018-09-16 19:44:34 2.07692 R 31*90 19.89 0.05 21.9 The photometry is based on several nearby SDSS-DR9 stars. SDSS-DR9_id R(Lupton) J220926.80+250130.1 15.705 J220922.87+250206.0 16.156 J220929.88+250257.7 15.812 J220928.05+250309.0 17.230 J220928.90+250327.6 15.524 J220924.12+250415.7 15.485 J220920.37+250610.6 15.050 J220902.04+250312.5 15.321 -- Лена Мазаева
GCN 23245 table
GRB_name GRB180914B
GCN_number 23245
Detection_method Optical
ra 332.3564°
decl 25.0620°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23245 SUBJECT: GRB 180914B: MASTER OT automatic dtection DATE: 18/09/17 11:10:54 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tiurina, D. Vlasenko, V.Kornilov, A.Kuznetsov, V.Chazov, I. Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, Lomonosov Moscow State University,SAI D.Svinkin (Ioffe Institute, Sankt Petersburg) A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory D. Buckley, South African Astronomical Observatory (SAAO) R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias (IAC) R. Podesta, F. Podesta, C. Lopez, C.Francile Observatorio Astronomico Felix Aguilar (OAFA) H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) O. Gres, N.M.Budnev , Yu.Ishmuhametova Irkutsk State University (ISU) A. Gabovich, V. Yurkov, Yu. Sergienko Blagoveschensk Educational State University (BSPU) MASTER-Tunka robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Tunka Astrophysical Center (Baykal Lake, Applied Physics Institute, Irkutsk State University, Russia) was starting survey on the LAT GRB180914.77 error-box (ra=22 09 47 dec=+24 52 47 r=0.33) 9409 sec after notice time and 79012 sec after trigger time at 2018-09-15 16:19:55 UT. The 5-sigma upper limit on our first (180s exposure) set is about 19.7 mag MASTER OT J220925.53+250343.3 - Afterglow MASTER-Tunka auto-detection system discovered OT source at (RA, Dec) = 22h 09m 25.53s +25d 03m 43.3s on 2018-09-15 16:19:55.393UT. Error is 0.7 arcsec. This position is coincident with late XRT (P. A. Evans, GCN 23234) and KAIT (WeiKang Zheng and Alexei V. Filippenko, GCN 23237) positions. The OT magnitude in clear filter is 19.2m (limit 19.7m). This is the first optical magnitude ( see also Eleonora Troja GCN 23238, A. de Ugarte Postigo et al., GCN 23239; N. Paul M. Kuin et al., GCN 23241; Eleonora Troja et al., GCN 23243). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2011-12-15.46200 UT with unfiltered magnitude limit 20.0m. The discovery and refernces images are available at http://master.sai.msu.ru/static/OT/MASTEROTJ220925.53+250343.3.jpg The galactic latitude b = -25 deg. The observations made on zenit distance = 28 deg.The moon (38 % bright part) below the horizon (The altitude of the Moon is -17 deg. ). The sun altitude is -34.5 deg. The object can be observed till sunrise at 2018-09-15 22:42:06
GCN 23246 table
GRB_name GRB180914B
GCN_number 23246
Detection_method Konus-Wind Det
redshift 1.0960
Circular_text TITLE: GCN CIRCULAR NUMBER: 23246 SUBJECT: GRB 180914B: VLT/X-shooter spectroscopic redshift DATE: 18/09/17 15:15:17 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst P. D'Avanzo (INAF/OABr), K. E. Heintz (Univ. Iceland and DAWN/NBI), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), A. J. Levan (Univ. Warwick), L. Izzo (HETH/IAA-CSIC), D. B. Malesani (DAWN/NBI and DARK/NBI), D. A. Kann (HETH/IAA-CSIC), N. R. Tanvir (Univ. Leicester), report on behalf of the Stargate collaboration: We observed the optical counterpart (e.g. Zheng & Filippenko, GCN 23237) of GRB 180914B, detected by AGILE (Ursi et al., GCN 23226; Verrecchia et al., GCN 23231), Fermi/LAT (Bissaldi & Longo, GCN 23232), and Konus-Wind (Frederiks et al., GCN 23240). We used the X-shooter spectrograph on the ESO VLT UT2 (Kueyen), for a total exposure of 2x600 s, starting on 2018 September 17.07 UT (2.30 days after the GRB). The covered wavelength range is 3000-21000 AA, and the seeing was relatively poor, around 1.5". From a 15-s acquisition image, we measure the magnitude of the afterglow as r = 20.37 +- 0.04 (AB), calibrated against the Pan-STARRS catalog. Several absorption features are detected superimposed on the afterglow continuum. Among them, we identify Mn II, Al III, Fe II, Mg II, Mg I, Ca II, all at the common redshift of z = 1.096. At the same redshift, fine-structure lines from Fe II are also identified, thus firmly establishing this value as the GRB redshift. A few emission lines from the underlying host are also visible. We identify the [O II] doublet and [O III] 5008, while other commonly observed features lie at this redshift in regions of poor atmospheric transparency or low S/N. We note that our spectroscopic value is larger than the photometric redshift of the putative host galaxy as listed in the SDSS catalog (https://skyserver.sdss.org/dr14/en/tools/explore/Summary.aspx?id=1237680331629267013), which is however based on low-S/N photometry. At z = 1.096, the isotropic-equivalent energy radiated in gamma-rays is 3.6*10^54 erg, using the Konus-Wind fluence (1.15*10^-3 erg cm^-2; Frederiks et al., GCN 23240). This ranks among the highest measured values for GRBs. We acknowledge the ESO staff at Paranal for their support, in particular Willem-Jan de Wit, Romain Thomas and Rodrigo Palominos.
GCN 23249 table
GRB_name GRB180914B
GCN_number 23249
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23249 SUBJECT: GRB 180914B : continued TSHAO optical observations DATE: 18/09/17 20:04:01 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Pozanenko (IKI), I. Reva (FAPHI), A. Kusakin (FAPHI), A. Volnova (IKI), M. Krugov (FAPHI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 180914B (Ursi, et al., GCN 23226; Bissaldi et al., GCN 23232; Frederiks et al., GCN 23240) with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting on September 17 (UT) 14:28:30. We observed the object reported e.g. (Zheng & Filippenko GCN 23237; Troja et al. GCN 23238; de Ugarte Postigo et al., GCN 23239; Paul & Kuin, GCN 23241). Preliminary photometry of the object is following. Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2018-09-17 14:28:30 2.87843 R 60*60 20.53 0.07 22.2 The photometry is based on several nearby SDSS-DR9 stars SDSS-DR9_id R(Lupton) J220926.80+250130.1 15.705 J220922.87+250206.0 16.156 J220929.88+250257.7 15.812 J220928.05+250309.0 17.230 J220928.90+250327.6 15.524 J220924.12+250415.7 15.485 J220920.37+250610.6 15.050 J220902.04+250312.5 15.321
GCN 23250 table
GRB_name GRB180914B
GCN_number 23250
Detection_method AstroSat CZTI
Circular_text TITLE: GCN CIRCULAR NUMBER: 23250 SUBJECT: GRB 180914B: AstroSat CZTI detection DATE: 18/09/17 20:55:04 GMT FROM: Vidushi Sharma at IUCAA T. Khanam, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data showed the detection of a long GRB 180914B, which was also detected by AGILE (MCAL: Ursi A. et al., GCN 23226 and GRID: Verrecchia F. et al., GCN 23231), Fermi-LAT (Bissaldi E. et al., GCN 23232), Swift-XRT (D'Ai A. et al., GCN 23236) and Konus-Wind (Frederiks D. et al., GCN 23240). The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 18:23:02.500 UT. The measured peak count rate is 3258 cts/s above the background in combined data of four quadrants, with a total of 105168 cts. The local mean background count rate was 657 cts/s. Using cumulative rates, we measure a T90 of 146.8 s. In preliminary analysis, we find that 7300 compton events are associated with this event. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN 23251 table
GRB_name GRB180914B
GCN_number 23251
Detection_method correction
ra 332.3564°
decl 25.0622°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23251 SUBJECT: GRB180914B: Swift UVOT position correction to circ. 23241 DATE: 18/09/17 21:25:15 GMT FROM: Paul Kuin at MSSL N.Paul M. Kuin (MSSL/UCL) reports on behalf of the Swift-UVOT Team: In GCN Circ. 23241 the position of the transient was correct in sexadecimal units, but incorrect in the degree units, where it should read: The UVOT source position is RA= 332.35638, Dec = 25.06217 (J2000). My apologies for any confusion caused by this mistake.
GCN 23252 table
GRB_name GRB180914B
GCN_number 23252
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23252 SUBJECT: GRB 180914B: GOTO optical detection DATE: 18/09/17 22:22:19 GMT FROM: Danny Steeghs at U.of Warwick/GOTO G.Ramsay (Armagh O.), K.Ulaczyk, D.Steeghs, J.Lyman (U. Warwick), M.Dyer (U. Sheffield), B.Gompertz, A.Levan, R.Cutter (U. Warwick) K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield), P.O'Brien, R.Starling (U. Leicester), S.Poshyachinda (NARIT), D.Pollacco (U. Warwick), E.Thrane (Monash U.), E.Palle (IAC) report on behalf of the GOTO collaboration: The Gravitational-wave Optical Transient Observer observed the field of the long GRB 180914B (Ursi et al. GCN Circ. 23226, Bissaldi et al. GCN Circ. 23232) from Roque de los Muchachos Observatory. In a combined L-band image (400-700nm passband), with a total exposure time of 600s at a mid-time 2018-09-16 21:57:04 UT, 2.149 days since burst, we detect the optical counterpart (Zheng et al. GCN Circ. 23237; Troja GCN Circ. 23238; de Ugarte Postigo et al. GCN Circ. 23239; Mazaeva et al. GCN Circ. 23244; Lipunov et al. GCN Circ. 23245) with a preliminary magnitude of g=20.9 +/- 0.2 based on a comparison to Panstarrs g-band calibrators. GOTO is operated at the La Palma observing facilities of the University of Warwick on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT) and the Instituto de Astrofisica de Canarias (IAC) (https://goto-observatory.org/)
GCN 23253 table
GRB_name GRB180914B
GCN_number 23253
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23253 SUBJECT: GRB 180914B: DDOTI/OAN Detection and Confirmation of Fading DATE: 18/09/18 00:55:28 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Eleonora Troja (GSFC), Rosa L. Becerra (UNAM), William H. Lee (UNAM), and Alexander Kutyrev (GSFC) report: We observed the field of GRB 180914B (Ursi et al., GCN Circ. 23226) with the DDOTI/OAN wide-field imager at the Observatorio Astronomico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) from 2018-09-16 02:54 to 06:02 (32.5 to 35.7 hours after burst) and 2018-09-17 02:58 to 04:17 (56.6 to 57.9 after burst) obtaining 7200 and 3060 seconds exposure with no filter. We detect the optical counterpart (Zheng & Filippenko, GCN Circ. 23237; Troja, et al., GCN Circ. 23238) with the following magnitudes: w = 19.45 +/- 0.10 (on 2018-09-16) w = 20.25 +/- 0.31 (on 2018-09-17) These AB magnitudes are calibrated against the Pan-STARRS1 catalog and are not corrected for Galactic extinction in the direction of the GRB. We confirm the fading reported by de Ugarte Postigo et al. (GCN Circ. 23239), Troja et al. (GCN Circ. 23243), and Mazaeva et al. (GCN Circ. 23249). DDOTI/OAN imaged the entire Fermi/LAT error region (Bissaldi et al., GCN Circ. 23232). We confirm that there were no other uncatalogued sources in the region on 2019-09-16 to a 10-sigma limit of w = 19.4. We thank the staff of the Observatorio Astronomico Nacional in San Pedro Martir.
GCN 23255 table
GRB_name GRB180914B
GCN_number 23255
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23255 SUBJECT: GRB 180914B: OAJ multi-color follow-up DATE: 18/09/19 18:32:38 GMT FROM: Alexander Kann at IAA-CSIC L. Izzo, M. Blazek (both HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, C. C. Thoene, K. Bensch (all HETH/IAA-CSIC), R. Martone (U. Ferrara), W. Schoenell (Federal U. of Rio Grande do Sul), H. Vazquez Radio, M. C. Diaz-Martin, and S. Rodriguez-Llano (all OAJ) report: We have continued to monitor GRB 180914B (Ursi et al., GCN 23226; Verrecchia et al., GCN 23231; Bissaldi et al. GCN 23232; D'Ai et al., GCN 23236) with the 0.8m T80 telescope of the Javalambre Astrophysical Observatory (Teruel, Spain). Observations consisted of a series of 3x300 s griz exposures, starting at 22:47:49 UT on September 16 (2.18 days after the GRB detection). The afterglow is clearly detected in all stacked images. We measure the following magnitudes (AB system): g' = 20.73 +/- 0.05 mag at 2.1875 days, r' = 20.27 +/- 0.08 mag at 2.2003 days, i' = 19.94 +/- 0.07 mag at 2.2260 days, z' = 19.62 +/- 0.07 mag at 2.2413 days, as compared to nearby PANSTARRS stars.
GCN 23256 table
GRB_name GRB180914B
GCN_number 23256
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23256 SUBJECT: GRB 180914B: OSN Detection and light curve/SED analysis DATE: 18/09/19 18:33:37 GMT FROM: Alexander Kann at IAA-CSIC D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), L. Izzo, C. C. Thoene, M. Blazek, K. Bensch (all HETH/IAA-CSIC), and A. Sota (IAA/CSIC) report: We observed the location of the extremely bright AGILE/Fermi GRB 180914B (Ursi et al., GCN #23226; Bissaldi et al., GCN #23232) with the T150 telescope of the Sierra Nevada Observatory (OSN). We obtained 3 x 180 s images in the Ic band, centered 3.157 days after the GRB. The afterglow (e.g., Zheng & Filippenko, GCN #23237; Troja et al., GCN #23238; de Ugarte Postigo et al., GCN #23239) is clearly detected, and we derive Ic (AB) = 20.28 +/- 0.06 mag vs. several SDSS comparison stars, using the transformation equations of Lupton (2005). Using the photometry given in the GCNs so far (Zheng & Filippenko, GCN #23237; Troja et al., GCN #23238, #23243; de Ugarte Postigo et al., GCN #23239; Kuin, GCN #23241; Mazaeva et al., GCN #23244, #23249; Lipunov et al., GCN #23245; D'Avanzo et al., GCN #23246; Ramsay et al., GCN #23252; Watson et al., GCN #23253, Izzo et al., GCN #23255), we find the optical afterglow can be fit by an achromatic simple power-law with a decay slope alpha = 1.65 +/- 0.02 (taking host-galaxy magnitudes from SDSS into account). The SED (from u to H band) is well-fit with a small amount of SMC extinction, we find beta = 0.94 +/- 0.11, A_V = 0.09 +/- 0.07 (assuming F_nu ~ t^(-alpha)*nu^(-beta) ). Note the earliest detection, from MASTER, lies significantly below the back-extrapolation of the later decay slope, indicating a rebrightening may have taken place.
GCN 23278 table
GRB_name GRB180914B
GCN_number 23278
Detection_method INTEGRAL
Circular_text TITLE: GCN CIRCULAR NUMBER: 23278 SUBJECT: INTEGRAL detections of the prompt gamma-ray emission of GRB 180914B DATE: 18/09/28 11:05:12 GMT FROM: Volodymyr Savchenko at ISDC,U of Geneve J. Rodi, A. Bazzano, P. Ubertini, L. Natalucci (IAPS-Roma) C. Ferrigno, V. Savchenko (ISDC, University of Geneva, CH) E. Kuulkers (ESTEC/ESA, The Netherlands) We have analyzed the public INTEGRAL data of IBIS/PICsIT (200 - 2600 keV) and SPI-ACS(>75 keV) in coincidence with the long, bright GRB 180914B, which was initially reported by AGILE/MCAL (GCN 23226), AGILE/GRID (GCN 23231), and Fermi/LAT(GCN 23232). The INTEGRAL orientation was 98.4 degrees from the GRB location and implies a near optimal response for SPI-ACS and a suppressed response for PICsIT (Savchenko et al. 2017, A&A 603, A46). The GRB was clearly detected in SPI-ACS until about T0+250s (T0=2018-09-14 18:23:02.22) and shows 8 flaring events, of which 7 show large variability detected down to the 50 ms time-resolution of the detector. It was also detected in PICsIT until approximately T0+130s, of which 5 flaring events are clearly seen. Because of the unfavorable viewing angle for PICsIT, the burst is predominately seen above 460 keV with significant emission up to 1.2 MeV. The SPI-ACS light curve can be found at: https://www.isdc.unige.ch/integral/ibas/cgi-bin/ibas_acs_web.cgi/?trigger=2018-09-14T18-23-01.00-00000-00000-0
GCN 23287 table
GRB_name GRB180914B
GCN_number 23287
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23287 SUBJECT: GRB 180914B: RTT150 optical observations DATE: 18/10/01 20:36:17 GMT FROM: Rodion Burenin at IKI, Moscow A. Lyapin, I. Zaznobin, R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Bikmaev, E. Irtuganov, N. Sakhibullin (KFU/AST), I. Khamitov, S. Ozdemir (TUG), E. Gogus (Sabanci Uni.) report: We observed the field of GRB 180914B (Ursi et al., GCN 23226, Bissaldi et al., GCN 23232, Ai et al., GCN 23236) with the Russian-Turkish 1.5-m optical telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) using the TFOSC instrument. We obtained series of exposures in SDSS gri filters, starting at 18:30 UT on Sep 16, 2018. The optical transient (Zhen and Filippenko, GCN 23237, Troja et al., GCN 23238, de Ugarte Postigo et al., GCN 23239) was detected in all images. We estimated the following magnitudes for the OT: g: 20.97 +- 0.02 r: 20.38 +- 0.02 i: 20.04 +- 0.02 calibrated against SDSS secondary standards.
GCN 23288 table
GRB_name GRB180914B
GCN_number 23288
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 23288 SUBJECT: GRB 180914B: RTT150 optical observations DATE: 18/10/01 20:38:00 GMT FROM: Rodion Burenin at IKI, Moscow E. Irtuganov, I. Bikmaev, N. Sakhibullin (KFU/AST), A. Lyapin, I. Zaznobin, R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Khamitov, S. Ozdemir (TUG), E. Gogus (Sabanci Uni.) report: We observed the field of GRB 180914B (Ursi et al., GCN 23226, Bissaldi et al., GCN 23232, Ai et al., GCN 23236) with the Russian-Turkish 1.5-m optical telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) using the TFOSC instrument. We obtained direct images in SDSS r filter, on Sep 18, 19 and 21, 2018. The optical transient (Zhen and Filippenko, GCN 23237, Troja et al., GCN 23238, de Ugarte Postigo et al., GCN 23239) was detected in all images. We estimated the following magnitudes for the OT: Sep 18: 21.21 +- 0.03 Sep 19: 21.99 +- 0.05 Sep 21: 22.28 +- 0.10 calibrated against SDSS secondary standards. Therefore, approximately power law light curve is observed, with a decay slope near -1.53, which is approximately consistent with the slope measured earlier by Kann et al., GCN 23256. Note, that some deviations from simple power law decay at the level of 0.2-0.3 mag are also observed in our data.