//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26993 SUBJECT: GRB 200205B: Swift detection of a burst with optical counterpart DATE: 20/02/05 19:46:01 GMT FROM: David Palmer at LANL P. A. Evans (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), K. L. Page (U Leicester) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 19:21:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200205B (trigger=954519 and 954520). Swift slewed to the burst after a short delay. The BAT on-board calculated location is RA, Dec 107.861, -56.506 which is RA(J2000) = 07h 11m 27s Dec(J2000) = -56d 30' 21" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a peak about 20 seconds long (trigger 954519) followed by a brighter more complex peak structure 350 s later (trigger 954520) with a peak countrate of 3500 counts/s. Due to the double trigger, the complete BAT lightcurve is not immediately available. The XRT began observing the field at 19:27:26.3 UT, 342.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 107.7881, -56.4875 which is equivalent to: RA(J2000) = 07h 11m 09.14s Dec(J2000) = -56d 29' 15.0" with an uncertainty of 2.8 arcseconds (radius, 90% containment). This location is 37 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 consistent with the Galactic value of 1.04 x 10^21 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 1.26e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 351 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 07:11:09.15 = 107.78811 DEC(J2000) = -56:29:15.1 = -56.48753 with a 90%-confidence error radius of about 0.61 arc sec. This position is 0.8 arc sec. from the center of the XRT error circle. The estimated magnitude is 16.43 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.11. Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). 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: 26995 SUBJECT: GRB 200205B: LCO Optical Detection DATE: 20/02/05 21:37:40 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 200205B (Evans et al., GCN 26993) with the LCO 1-m Sinistro instrument at the South African Astronomical Observatory site on February 5, from 19:38 to 20:00 UT (corresponding to 0.28 to 0.82 hours after the GRB trigger time) with the Bessel R and I filters. We performed a series of 5x120s exposures in each band. We detect a source that is consistent with the Swift-XRT position (Evans et al., GCN 26993) and other optical detections (Lipunov et al., GCN 26991) and not present in either USNO-B1.0 or 2MASS surveys with the following magnitudes: R = 18.56 +/- 0.04 I = 17.15 +/- 0.03 These magnitudes are calibrated against several USNO-B1.0 objects near the GRB location and is not corrected for Galactic Extinction. R.S. is funded by NSF AST grant #1831682 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26998 SUBJECT: GRB 200205B: VLT/X-shooter redshift DATE: 20/02/06 03:17:38 GMT FROM: Daniele B Malesani at DTU Space J.-B. Vielfaure (GEPI - Paris Observatory), D. Xu (NAO/CAS), J. Palmerio (GEPI - Paris Observatory), D. B. Malesani (DTU Space), L. Izzo (DARK/NBI), D. A. Kann (HETH/IAA-CSIC), A. J. Levan (Radboud Univ.), G. Pugliese (Univ. Amsterdam), N. R. Tanvir (Univ. Leicester) report on behalf of the Stargate collabaration: We observed the optical afterglow of GRB 200205B (Evans et al., GCN 26993) using the ESO VLT UT2 (Kueyen) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-25000 AA, and consist of 4 exposures by 600 s each. The observation mid time was 2020 Feb 6.063 UT (6.16 hr after the GRB). In a 30 s image taken with the acquisition camera on Feb 6.041 UT, we detect the optical afterglow, for which we measure a magnitude r = 20.34 +- 0.03 AB (calibrated against nearby stars from the SkyMapper catalog; Wolf et al. 2018, PASA, 35, 010; https:doi.org/10.4225/41/593620ad5b574). We clearly detect continuum over the wavelength range 3100-24000 AA. From detection of multiple absorption features, which we interpret as due to C ii, Si iv, Si ii, C iv, Fe ii, Al ii, Mg ii, we infer a redshift z = 1.465. Emission lines are also detected, which we interpret as due to the [O ii] and [O iii] doublets, Hbeta, and Halpha, all at the above quoted redshift. We acknowledge excellent support from the ESO observing staff in Paranal, in particular J. Corral-Santana and J. Velasquez. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26999 SUBJECT: GRB 200205B: Enhanced Swift-XRT position DATE: 20/02/06 03:52:10 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 1822 s of XRT Photon Counting mode data and 5 UVOT images for GRB 200205B, 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 = 107.78760, -56.48741 which is equivalent to: RA (J2000): 07h 11m 9.03s Dec (J2000): -56d 29' 14.7" with an uncertainty of 1.6 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: 27001 SUBJECT: GRB 200205B: Swift-XRT refined Analysis DATE: 20/02/06 16:39:26 GMT FROM: Phil Evans at U of Leicester J.P. Osborne (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (ASDC), V. D'Elia (ASDC), J. D. Gropp (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), 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 6.5 ks of XRT data for GRB 200205B (Evans et al. GCN Circ. 26993), from 332 s to 46.4 ks after the BAT trigger. The data comprise 360 s in Windowed Timing (WT) mode (the first 8 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. 26999). The late-time light curve (from T0+5.3 ks) can be modelled with a power-law decay with a decay index of alpha=0.76 (+0.14, -0.13). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.129 (+0.027, -0.026). The best-fitting absorption column is 4.9 (+1.2, -1.1) x 10^21 cm^-2, at a redshift of 1.465, in addition to the Galactic value of 1.0 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.93 (+0.19, -0.13) and a best-fitting absorption column of 1 (+35, -1) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 1.0 x 10^21 cm^-2 Intrinsic column: 1 (+35, -1) x 10^20 cm^-2 at z=1.465 Photon index: 1.93 (+0.19, -0.13) If the light curve continues to decay with a power-law decay index of 0.76, the count rate at T+24 hours will be 0.018 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.1 x 10^-13 (7.4 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00954519. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27004 SUBJECT: GRB 200205B: ESO/NTT near-infrared imaging DATE: 20/02/06 22:22:43 GMT FROM: Daniele B Malesani at DTU Space D. B. Malesani (DTU Space), D. M. Russell, P. Saikia, M. C. Baglio (NYU Abu Dhabi), report: The optical counterpart of GRB 200205B (Evans et al., GCN 26993; Strausbaugh & Cucchiara, GCN 26995; Vielfaure et al., GCN 26998) was observed with the ESO New Technology Telescope equipped with the SofI imager on two different epochs during the night of 2020 Feb 5-6. Observations were carried out under ESO program 0104.D-0945(A) (PI Russell). The afterglow is well detected in the first epoch in the J and Ks filters, and is marginally detected in the second observation. Calibrated to the 2MASS survey, we obtain the following magnitudes (Vega): K = 18.07 +- 0.10  on Feb 6.164 UT  (0.356 days after the GRB) J = 19.43 +- 0.10  on Feb 6.145 UT  (0.338 days after the GRB) J = 20.57 +- 0.33  on Feb 6.368 UT  (0.561 days after the GRB) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27006 SUBJECT: GRB 200205B: Swift/UVOT Detection DATE: 20/02/07 02:46:45 GMT FROM: Kira Simpson at PSU GRB 200205B: Swift/UVOT Detection K. K. Simpson (PSU) and P. A. Evans (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 200205B 352 s after the BAT trigger (Evans et al., GCN Circ. 26993). A source consistent with the XRT position (Evans et al. GCN Circ. 26993) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 07:11:09.15 = 107.78812 (deg.) Dec (J2000) = -56:29:15.3 = -56.48759 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 6386 6586 196 18.92+-0.10 white 383 1042 478 16.81+-0.03 v 540 733 38 16.88 +/- 0.17 b 638 833 38 17.74 +/- 0.15 u 614 808 38 17.25 +/- 0.16 w1 589 783 38 16.88+-0.20 m2 564 758 38 17.12 +/- 0.28 w2 689 1056 46 >17.77 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.11 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27012 SUBJECT: GRB 200205B: Swift-BAT refined analysis DATE: 20/02/08 02:03:36 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), P. A. Evans (U Leicester), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+1361 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200205B (trigger #954519 and #954520) (Evans et al., GCN Circ. 26993). We have combined the data from two triggers (#954519 and #954520) for the analysis. All the times in this circular are relative to the trigger time from #954519. The BAT ground-calculated position is RA, Dec = 107.760, -56.488 deg which is RA(J2000) = 07h 11m 02.3s Dec(J2000) = -56d 29' 18.1" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 47%. The mask-weighted light curve shows several pulses that start from ~T+20 s and end at ~T+550 s. The first prominent pulse occurs at ~T+60 s, followed by another significant structure with several overlapping pulses from ~T+380 s to ~T+520 s. There is a data gap from T+63 s to T+160 s, likely due to problems of saving data because of the double triggers. T90 (15-350 keV) is 458.0 +- 5.4 sec (estimated error including systematics). Because of the data gap for part of the first pulse, we performed the time-averaged spectrum for the interval of the second multi-pulse structure from T+387.008 to T+520.396 sec. This interval is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.36 +- 0.22, and Epeak of 65.6 +- 10.8 keV (chi squared 41.92 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.4 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+438 sec in the 15-150 keV band is 2.0 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.84 +- 0.05 (chi squared 58.00 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/954519/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27027 SUBJECT: GRB 200205B: Chilescope optical observations DATE: 20/02/09 13:51:47 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Pozanenko (IKI), M. Krugov (AFIF), A. Volnova (IKI), S. Belkin (IKI) report on behalf of IKI-FuN follow-up collaboration: We observed the Swift GRB 200205B (Evans et al., GCN 26993) with Chilescope RC-1000 started on Feb. 7 (UT) 03:04:55 in r'-filter. We marginally detect optical afterglow (Lipunov et al., GCN 26991; Evans et al., GCN 26993; Strausbaugh et al., GCN 26995; Vielfaure et al., GCN 26998; Malesani et al., GCN 27004; Simpson et al., GCN 27006). Preliminary photometry is following. Date UT start MJD_mid Filter Exp. OT(AB) S/N UL (mid, days) (s) 2020-02-07 03:04:55 1.33613 r' 2*1200 22.2 2.0 22.0 The photometry is based on nearby stars from the SkyMapper catalog SkyMapper_id r 293365688 17.550 293359963 16.213 293359881 15.816 293365677 17.659 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27034 SUBJECT: Konus-Wind observation of GRB 200205B DATE: 20/02/11 13:05:44 GMT FROM: Anastasia Tsvetkova at Ioffe Institute A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Lysenko, A. Ridnaia and T. Cline on behalf of the Konus-Wind team, report: The long GRB 200205B which triggered Swift/BAT at T0=T0(BAT)=19:21:43 UT (Swift/BAT detection: Evans et al., GCN 26993; Ukwatta et al., GCN 27012;) was detected by Konus-Wind in the waiting mode. The burst light curve shows two emission episodes: the first pulse lasts from ~T0+48.6 s to ~T0+89.8 s, and the second pulse lasts from ~T0+390.1 s to ~T0+525.5 s. The total duration of the burst is ~477 s. As observed by Konus-Wind, the burst had a fluence of 1.12(-0.05,0.26)x10^-5 erg/cm2 and a 2.944-s peak flux, measured from ~T0(BAT)+437.202 s, of 1.55(-0.09,+0.44)x10^-7 erg/cm2/s (both in the 20 keV - 10 MeV energy range). Fitting the K-W 3-channel spectrum o the initial pulse (from ~T0(BAT)+48.594 s to ~T0(BAT)+89.810 s) in the 20 keV - 1.5 MeV range by a simple power law model yields the PL index = 2.34(-0.06,+0.17), chi2 = 2.95 / 1 dof. Modelling the K-W 3-channel spectrum of the second pulse (from ~T0(BAT)+390.098 s to ~T0(BAT)+446.034 s) in the 20 keV - 1.5 MeV range by a power law with exponential cutoff model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.32(-0.59,+2.70), and Ep =87(-17,+13) keV. Assuming the redshift z=1.465 (Vielfaure et al., GCN 26998) and a standard cosmology model with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy release E_iso is ~6.5x10^52 erg, the peak luminosity L_iso is ~2.2x10^51 erg/s, and the rest-frame peak energy of the initial pulse spectrum, Ep,z, is ~ 214 keV. All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary. The K-W light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB200205B/