//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29061 SUBJECT: GRB 201216C: Swift detection of a burst DATE: 20/12/16 23:15:47 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC), M. J. Moss (GWU), K. L. Page (U Leicester), D. M. Palmer (LANL) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 23:07:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 201216C (trigger=1013243). Swift did not slew immediately to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 16.358, +16.537 which is RA(J2000) = 01h 05m 26s Dec(J2000) = +16d 32' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 50 sec. The peak count rate was ~13000 counts/sec (15-350 keV), at ~20 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+46.8 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is A. P. Beardmore (apb 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: 29063 SUBJECT: GRB 201216C: Fermi GBM Final Real-time Localization DATE: 20/12/16 23:17:45 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 23:07:25 UT on 16 Dec 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 201216C (trigger 629852850.753568 / 201216963). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 17.9, Dec = 16.8 (J2000 degrees, equivalent to J2000 01h 11m, 16d 48'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 93.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201216963/quicklook/glg_skymap_all_bn201216963.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201216963/quicklook/glg_healpix_all_bn201216963.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn201216963/quicklook/glg_lc_medres34_bn201216963.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29064 SUBJECT: GRB 201216C: Swift-XRT observations DATE: 20/12/17 00:58:40 GMT FROM: Phil Evans at U of Leicester S. Campana (INAF-OAB), G. Cusumano (INAF-IASF PA), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU) and J.A. Kennea (PSU) report on behalf of the Swift-XRT team: The XRT began observing the field of GRB 201216C at 23:56:58.5 UT, 2966.8 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 16.37114, 16.51659 which is equivalent to: RA(J2000) = 01h 05m 29.07s Dec(J2000) = +16d 30' 59.7" with an uncertainty of 3.5 arcseconds (radius, 90% containment). This location is 86 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (5.04 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 7.4 (+2.86/-2.53) x 10^21 cm^-2 (90% confidence). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29066 SUBJECT: GRB 201216C: VLT afterglow candidate discovery DATE: 20/12/17 02:36:55 GMT FROM: Luca Izzo at DARK/NBI L. Izzo (DARK/NBI), D. B. Malesani (DTU Space) and D. A. Kann (HETH, IAA/CSIC) report: We observed the field of GRB 201216C (Beardmore et al., GCN #29061, Fermi GBM team, GCN #29063) using the ESO VLT UT3 (Melipal) equipped with the X-shooter acquisition camera. Observations started at 01:18:47 UT on 2020-12-17 (2.19 hr after the BAT trigger) and consisted of 3x40 s, 3x30 s, 3x60 s exposures obtained in the Sloan g', r', z' bands, respectively. We detect a new source at coordinates RA: 01:05:28.980, Dec: +16:31:00.0 (J2000.0), consistent with the Swift-XRT refined position (Campana et al., GCN #29064). No source is detected in archival Pan-STARRS images at this position, we therefore consider it to be the afterglow of GRB 201216C. From the stacked r'-band image we report a preliminary magnitude of 21.81+-0.05 mag (AB). We acknowledge excellent support from the ESO observing staff in Paranal, in particular Zahed Wahhaj and Bin Yang. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29067 SUBJECT: GRB 201216C: Enhanced Swift-XRT position DATE: 20/12/17 05:30:00 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 656 s of XRT Photon Counting mode data and 3 UVOT images for GRB 201216C, 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 = 16.37032, +16.51612 which is equivalent to: RA (J2000): 01h 05m 28.88s Dec (J2000): +16d 30' 58.0" 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: 29070 SUBJECT: GRB 201216C: FRAM-ORM afterglow confirmation DATE: 20/12/17 11:16:09 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov Martin Jelinek and Jan Strobl (ASU CAS Ondrejov, CZ), Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza (Institute of Physics, Prague, CZ) report: The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted robotically to the alert of GRB201216C (Beardmore et al GCNC 29061, Fermi/GBM team GCNC 29063, Campana et al. GCNC 29064 and Osborne et al. GCNC 29067), obtaining a series of 20s unfiltered images starting at 23:08:04.3 UT, i.e. 31.6s post trigger. We clearly detect the source reported by Izzo et al. (GCNC 29066) at the VLT. The observations by FRAM cover the onset of the afterglow and its peak. The joint fit of our final points from ~1ks post trigger and the VLT point provide a power-law decay rate of ~1.07, all of these confirm the afterglow nature of the transient and provide an extrapolation of the brightness to r~24.6 for the next night. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29071 SUBJECT: GRB 201216C: Swift/UVOT Upper Limits DATE: 20/12/17 11:19:46 GMT FROM: Samantha Oates at MSSL S. R. Oates (U.Birmingham) and A. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 201216C 2970 s after the BAT trigger (Beardmore et al., GCN Circ. 29061). No optical afterglow consistent with the enhanced XRT position (Osborne et al. GCN Circ. 29067) or the VLT position (Izzo et al., GCN Circ. 29066) 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 2970 3120 147 >20.0 white 2970 3739 344 >20.7 v 3950 4150 197 >19.1 b 3334 3534 197 >19.9 u 3129 3329 197 >19.3 m2 4154 4331 174 >19.3 w2 3745 3945 197 >19.7 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29073 SUBJECT: GRB 201216C: Fermi GBM detection DATE: 20/12/17 15:03:27 GMT FROM: Christian Malacaria at NASA-MSFC/USRA C. Malacaria (NASA-MSFC/USRA), P. Veres (UAH), C. Meegan (UAH) and E. Bissaldi (Politecnico and INFN Bari) report on behalf of the Fermi GBM Team: "At 23:07:25.75 UT on 16 December 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 201216C (trigger 629852850 / 201216963), which was also detected by the Swift/BAT (Beardmore et al. 2020, GCN 29061). The Fermi GBM Final Real-time Localization (GCN 29063) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 94 degrees. GRB 201216C is particularly bright and hard. The GBM light curve shows a broad, structured peak with a duration (T90) of about 29.9 s (50-300 keV). The time-averaged spectrum from T0-0.003 s to T0+49.665 s is best fit by a Band function with Epeak = 326 +/- 7 keV, alpha = -1.06 +/- 0.01, and beta = -2.25 +/- 0.03. The event fluence (10-1000 keV) in this time interval is (1.41 +/- 0.06)E-4 erg/cm^2. The 1-sec peak photon flux measured starting from T0+24.8 s in the 10-1000 keV band is 54.9 +/- 0.6 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: 29074 SUBJECT: GRB 201216C: AstroSat CZTI detection DATE: 20/12/17 15:10:28 GMT FROM: Gaurav Waratkar at IIT Bombay D. Nadella (NITK), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta (IUCAA), P. Sawant (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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, 2020, arxiv:2011.07067) showed detection of a bright long GRB 201216C, which was also detected by Swift BAT (GCN #29061) and Fermi GBM (GCN #29063). The source was clearly detected in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-12-16 23:07:47.500 UT. The measured peak count rate associated with the burst is 1160 (+72, -40) cts/s above the background in the combined data of four quadrants, with a total of 18073 (+682, -728) cts. The local mean background count rate was 652 (+4, -4) cts/s. Using cumulative rates, we measure a T90 of 29 (+2, -2) s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-12-16 23:07:47.247 UT. The measured peak count rate is 1679 (+106, -78) cts/s above the background in the combined Veto data of four quadrants, with a total of 22904 (+1443 -1654) cts. The local mean background count rate was 2400 (+7, -8) cts/s. We measure a T90 of 26 (+4, -2) s from the cumulative Veto light curve. 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29075 SUBJECT: GRB 201216C: MAGIC detection in very high energy gamma rays DATE: 20/12/17 17:23:13 GMT FROM: Oscar Blanch at MAGIC Collaboration O.Blanch (IFAE-BIST Barcelona), F. Longo (University and INFN Trieste), A. Berti (INFN Torino), S. Fukami (ICRR University of Tokyo), Y. Suda (MPP Munich), S. Loporchio (University and INFN Bari), S. Micanovic (University of Rijeka), J. G. Green (INAF Rome), V. Pinter (IFAE-BIST), M. Takahashi (ICRR University of Tokyo), on behalf of the MAGIC collaboration report: On December 16, 2020, the MAGIC telescopes observed GRB 201216C following the trigger by Swift-BAT and Fermi-GBM (Beardmore et al., GCN 29061, Fermi/GBM team GCN 29063). MAGIC started observations under good conditions about 57 seconds after the GRB onset. The preliminary offline analyses show an excess above 5 sigma, compatible with the GRB position reported by the Swift and Fermi teams. Refined off-line analyses of the data are ongoing. We strongly encourage follow-up observations by other instruments at all wavelengths. The MAGIC point of contact for this burst is O. Blanch (blanch@ifae.es). Burst Advocate for this burst is F. Longo (francesco.longo@ts.infn.it). MAGIC is a system of two 17m-diameter Imaging Atmospheric Cherenkov Telescopes located at the Observatory Roque de los Muchachos on the Canary island La Palma, Spain, and designed to perform gamma-ray astronomy in the energy range from 50 GeV to greater than 50 TeV. -- Avís - Aviso - Legal Notice - (LOPD) - http://legal.ifae.es //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29076 SUBJECT: GRB 201216C: Fermi-LAT upper limit DATE: 20/12/17 19:15:12 GMT FROM: Elisabetta Bissaldi at INFN,Bari E. Bissaldi (Politecnico and INFN Bari), N. Omodei (Stanford University), D. Kocevski (UAH), M. Axelsson (KTH & Stockholm Univ.), F. Longo (University and INFN Trieste), and E. Moretti (IFAE-BIST Barcelona) report on behalf of the Fermi-LAT Collaboration: Fermi-LAT observed the position of GRB 201216C, which was detected by Fermi-GBM (GCN Circ. 29073), Swift (GCN Circ. 29061, 29064), and MAGIC (GCN Circ. 29075). The GRB position was not in the LAT field of view at the time of the GBM trigger (T0 = 2019-12-16, 23:07:25.75 UT), and was not visible until ~T0+3500 s. The position remained visible until ~T0+5500 s. No significant high-energy gamma-ray emission associated with this burst was detected by the LAT in this time interval. A LAT upper limit (95% confidence level, 100 MeV - 1 GeV), assuming a photon index of -2.0, covering the same time interval is 7.3E-7 ph/s/cm2. The corresponding upper limit for energy flux is 3E-10 erg/s/cm2. The Fermi-LAT point of contact for this burst is Elena Moretti (moretti@ifae.es). 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29077 SUBJECT: GRB 201216C: VLT X-shooter spectroscopy and potential high redshift of a VHE-emitting GRB DATE: 20/12/17 22:12:41 GMT FROM: Alexander Kann at IAA-CSIC J.-B. Vielfaure (APC, Paris University), L. Izzo (DARK/NBI), D. Xu (NAOC), S. D. Vergani (GEPI, Observatoire de Paris), D. B. Malesani (DTU Space), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), V. D'Elia (ASI/SSDC, INAF/OAR), J. P. U. Fynbo (DAWN/NBI), D. A. Kann (HETH/IAA-CSIC), A. J. Levan (Radboud U. Nijmegen), G. Pugliese (API, Univ. Amsterdam), N. R. Tanvir (Univ. Leicester), D. Burgarella (AMU, CNRS, CNES, LAM), and A. Rossi (INAF-OAS) report on behalf of the Stargate Consortium: We obtained spectroscopic observations of the optical counterpart (Izzo et al., GCN #29066, Jelinek et al., GCN #29070) of the MAGIC-detected (Blanch et al., GCN #29075) GRB 201216C (Beardmore et al., GCN #29061, Malacaria et al., GCN #29073, Nadella et al., GCN #29074) with the ESO Very Large Telescope UT 3 (Melipal) equipped with the X-shooter spectrograph, covering the wavelength range 3200-22000 AA. Observations started at 01:30 UT on 2020-12-17, 2.38 hr after the burst, and consisted of 4 exposures of 600 s each. The afterglow is well-detected in the stacked spectrum, but the continuum is very red. As a consequence, the S/N drops dramatically from the red to the blue end. We identify a doublet which we tentatively match to Ca II H & K at z = 1.10. Unfortunately, no other lines are detected to confirm this value, though most of them would fall in a spectral region of poor S/N. We note that Ca II H&K absorption is uncommon in intervening absorbers, making it likely this is the actual redshift of the GRB, and that it does not lie at an even greater distance (in accordance with the VHE detection). A redshift of z = 1.1 would place this object among the most distant known VHE sources. Using the Fermi GBM parameters (Malacaria et al., GCN #29073), we derive a an observer-frame 10-1000 keV isotropic energy release of E_iso = (4.71 +/- 0.16) * 10^53 erg. Based on our grz photometry (Izzo et al., GCN 29066), we measure a spectral slope beta_opt = 4.1 +- 0.2 (Fnu propto nu^-beta), which is an unusually red value, suggesting significant extinction. This is confirmed by the optical-to-X-ray spectral index, beta_OX ~ 0.1 which indicates a very low optical/X-ray flux ratio, making this a bona fide dark GRB. We acknowledge excellent support from the ESO observing staff in Paranal, in particular, Diego Parraguez, Bin Yang, and Zahed Wahhaj. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29080 SUBJECT: GRB 201216C: Swift-BAT refined analysis DATE: 20/12/18 02:04:50 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), A. P. Beardmore (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-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 201216C (trigger #1013243) (Beardmore et al., GCN Circ. 29061). The BAT ground-calculated position is RA, Dec = 16.364, 16.538 deg which is RA(J2000) = 01h 05m 27.4s Dec(J2000) = +16d 32' 16.4" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 18%. The mask-weighted light curve shows a multi-peaked structure that starts at ~ T-16 s and ends at ~T+64 s. The main peak occurs at ~T+20 s. T90 (15-350 keV) is 48.0 +- 16.0 sec (estimated error including systematics). The time-averaged spectrum from T-15.89 to T+64.11 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.43 +- 0.03. The fluence in the 15-150 keV band is 4.5 +- 0.1 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+23.61 sec in the 15-150 keV band is 18.0 +- 1.1 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/1013243/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29084 SUBJECT: Konus-Wind detection of GRB 201216C DATE: 20/12/18 14:50:32 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, S. Golenetskii, R.Aptekar, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long GRB 201216C (Swift detection: Beardmore et al., GCN 29061; Fermi GBM detection: Malacaria et al., GCN 29071; AstroSat CZTI detection: Nadella et al., GCN 29074; MAGIC detection: Blanch et al., GCN 29075) triggered Konus-Wind (KW) at T0=83248.844 s UT (23:07:28.844). The burst light curve shows a multi-peaked structure with the total duration of ~40 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB201216_T83248/ As observed by Konus-Wind, the burst had a fluence of (1.86 ± 0.10)x10^-4 erg/cm^2 and a 64-ms peak energy flux, measured from T0+24.704, of (1.82 ± 0.12)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+24.832 s) is best fit in the 20 keV - 20 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -1.09 (-0.05,+0.06), the high energy photon index beta = -2.32 (-0.13,+0.10), the peak energy Ep = 333 (-28,+29) keV, chi2 = 102/97 dof. The spectrum near the peak count rate (measured from T0+18.944 to T0+26.368 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 = -0.99 (-0.05,+0.06), the high energy photon index beta = -2.24 (-0.14,+0.10), the peak energy Ep = 326 (-41,+47) keV, chi2 = 121/97 dof. Assuming the redshift z=1.1 (Vielfaure et al., GCN 29077) and a standard cosmology 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 = (6.2 ± 0.6)x10^53 erg, the peak luminosity L_iso = (1.3 ± 0.1)x10^53 erg/s, and the rest-frame peak energy of the time-integrated spectrum Ep,z=(700 ± 61) keV. With these values, GRB 201216C is within 68% prediction bands for both 'Amati' and 'Yonetoku' relations built for the sample of long KW GRBs with known redshifts (part I: Tsvetkova et al., ApJ 850 161, 2017; part II: Tsvetkova et al., ApJ, submitted), see http://www.ioffe.ru/LEA/GRBs/GRB201216_T83248/GRB201216C.pdf All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29085 SUBJECT: GRB 201216C: Liverpool Telescope First Hour Observations DATE: 20/12/18 14:51:28 GMT FROM: Manisha Shrestha at Liverpool John Moores U M. Shrestha (Liverpool JMU), A. Melandri (INAF), R. Smith (LJMU) , I.A. Steele (LJMU), S. Kobayashi (LJMU), C. Mundell (Univ. Bath), A. Gomboc (Univ. Nova Gorica), C. Guidorzi (Univ. Ferrara) report on behalf of a wider collaboration: We observed the field of Swift GRB 201216C (GCN 29061) with the 2.0m Liverpool Telescope (LT), La Palma on 2020 Dec 16 starting at 23:10:29.13 UT using the IO:O optical camera in the r’ bands. Data was calibrated with respect to nearby APASS secondary standard stars. We confirm the optical counterpart reported by Swift UVOT and VLT (GCN 29066). At T=177 seconds after the BAT trigger time, we measure r’ = 18.38. The r’ band light curve made along with VLT (GCN 29066) data point and inferred data from FRAM-ORM (GCN 29070) show a power law decay in flux vs time with alpha = 1. From the light curve, LT observations seem to be around the peak of afterglow. ________________________________ Important Notice: the information in this email and any attachments is for the sole use of the intended recipient(s). If you are not an intended recipient, or a person responsible for delivering it to an intended recipient, you should delete it from your system immediately without disclosing its contents elsewhere and advise the sender by returning the email or by telephoning a number contained in the body of the email. No responsibility is accepted for loss or damage arising from viruses or changes made to this message after it was sent. The views contained in this email are those of the author and not necessarily those of Liverpool John Moores University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29086 SUBJECT: GRB201216C: No significant detection in HAWC DATE: 20/12/18 17:04:28 GMT FROM: Hugo Ayala at Pennsylvania State University On 2020/12/16 at 23:07:31 UTC, following the trigger by Swift-BAT and Fermi-GBM (GCN 29061, GCN 29063), HAWC observed the position of GRB 201216C. The position of the GRB at the time of trigger (t0) fell just inside the field of view of HAWC, at 40 deg from zenith. We observed the position in the time range [t0-100s,t0+3600s]. At the end of the analysis, the position was at 25 deg from zenith. We scanned this range with time bins of 100s width. The time window advances every 20s, producing 80% overlap between different time windows. No emission was observed. The most conservative flux upper-limit at 95% C.L. measured during the time range is dN/dE = 4.05e-10 (E/TeV)^-2.0 [TeV^-1 cm^-2 s^-1] HAWC is a very-high-energy gamma-ray observatory operating in Central Mexico at latitude 19 deg. north. Operating day and night with over 95% duty cycle, HAWC has an instantaneous field of view of 2 sr and surveys 2/3 of the sky every day. It is sensitive to gamma rays from 300 GeV to 100 TeV. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29210 SUBJECT: GRB 201216C: TSHAO, Terskol, Mondy optical upper limits DATE: 20/12/31 17:43:53 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), M. Krugov (FAI), P. Levkina (INASAN), E. Klunko (ISTP), N. Pankov (IKI, HSE) report on behalf of GRB IKI FuN: We observed GRB 201216C (Beardmore et al., GCN 29061) with Zeiss-1000 (West) telescope of TSHAO, Zeiss-2000 telescope of Terskol observatory, and AZT-33IK telescope of Mondy observatory. The optical afterglow (Izzo et al., GCN 29066; Jelinek et al., GCN 29070; Oates et al., GCN 29071; Shrestha et al., GCN 29085) at possible redshift of z = 1.1 of presumably optically dark GRB (Vielfaure et al., GCN 29077) is not detected in our observations. Preliminary photometry of the field is following. Date UT start t-T0 Filter Exp. OT Err. UL. Telescope (mid, days) (s) 2020-12-17 14:20:49 0.6968 R 60*180 n/d n/d 19.8 Zeiss-1000(W) 2020-12-18 16:47:27 1.7653 R 28*180 n/d n/d 21.9 Zeiss-2000 2020-12-19 12:00:27 2.5681 R 45*120 n/d n/d 22.1 AZT-22 Photometry is based on USNO-B1.0 stars USNO-B1.0_id R2 1065-0011134 15.33 1065-0011173 15.44 1064-0011283 16.67 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29278 SUBJECT: GRB 201216C: Swift-XRT refined Analysis DATE: 21/01/08 02:49:56 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU) and A.P. Beardmore report on behalf of the Swift-XRT team: We have analysed 2.8 ks of XRT data for GRB 201216C (Beardmore et al. GCN Circ. 29061), from 3.0 ks to 1896.5 ks after the BAT trigger. The data comprise 466 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 29067). The light curve can be modelled with a power-law decay with a decay index of alpha=1.97 (+0.10, -0.09). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.35 (+0.17, -0.16). The best-fitting absorption column is 7.7 (+1.2, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 5.0 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.03 (+0.16, -0.15) and a best-fitting absorption column of 5.6 (+1.0, -0.9) 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 (8.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 5.6 (+1.0, -0.9) x 10^21 cm^-2 Galactic foreground: 5.0 x 10^20 cm^-2 Excess significance: 9.3 sigma Photon index: 2.03 (+0.16, -0.15) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01013243. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29280 SUBJECT: Correction to GCN 29278: GRB 201216C XRT refined analysis DATE: 21/01/08 11:59:30 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: The XRT refined analysis of GRB 201216C contained in GCN Circ. 29278 was incorrect, some of the data had been excluded from the analysis. The corrected analysis is below. We apologise for the confusion. We have analysed 5.2 ks of XRT data for GRB 201216C (Beardmore et al. GCN Circ. 29061), from 3.0 ks to 1938.0 ks after the BAT trigger. The data comprise 466 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 29067). The light curve can be modelled with an initial power-law decay with an index of alpha=2.09 (+0.16, -0.10), followed by a break at T+9078 s to an alpha of 1.07 (+0.15, -0.10). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.35 (+0.17, -0.16). The best-fitting absorption column is 7.7 (+1.2, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 5.0 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.03 (+0.16, -0.15) and a best-fitting absorption column of 5.6 (+1.0, -0.9) 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 (8.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 5.6 (+1.0, -0.9) x 10^21 cm^-2 Galactic foreground: 5.0 x 10^20 cm^-2 Excess significance: 9.3 sigma Photon index: 2.03 (+0.16, -0.15) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01013243. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29674 SUBJECT: GRB 201216C: VIRT optical observations DATE: 21/03/19 23:01:33 GMT FROM: Priyadarshini Gokuldass at U. of the Virgin Islands P. Gokuldass (UVI), D. Morris (UVI), N. Orange (OrangeWave Innovative Science, LLC), R. Strausbaugh (UVI), A. Cucchiara (UVI/College of Marin) report: We observed the field of GRB201216C (V. Lipunov et al., GCN 29062) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 12-16-2020 starting at 23:43:20.5 UT (T+36 mins). We performed a series of exposures in R filter with a total exposure of 2060 s. The weather conditions were very clear during the hours of observation with an average arimass of 1.0. We find no new source within the enhanced XRT position error circle (S. Campana et al., 29064) and report the following 3-sigma upper limit: T_mid ||Exposure ||Filter ||Limit T+ 1 hr ||2060s ||R ||>20.65 The limit is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction. The VIRT is still in the commissioning phase. This work is supported by NASA-MUREP-MIRO grant NNX15AP95A, NSF EiR AST Award 1901296, and NSF HBCU-UP AST Award 1831682. This message can be cited.