GRB201221D

This page lists all entries on GRB201221D in GRBweb

Summary Fermi GBM IPN Swift GCN 29112 GCN 29113 GCN 29117 GCN 29118 GCN 29119 GCN 29122 GCN 29124 GCN 29125 GCN 29128 GCN 29129 GCN 29130 GCN 29132 GCN 29133 GCN 29139 GCN 29140 GCN 29141 GCN 29142 GCN 29144 GCN 29148 GCN 29311

Summary table
Variable Value Source
GRB_name_Fermi GRB201221963
T0 23:06:34 UTC GCN_circulars,Swift Det
ra 171.0590° Swift
decl 42.1435° Swift
pos_error 5.57e-04° Swift
T90 0.144 s Fermi_GBM
T90_error 0.066 s Fermi_GBM
T90_start 23:06:34.295 UTC Fermi_GBM
fluence 6.36e-07 erg/cm² Fermi_GBM
fluence_error 2.36e-08 erg/cm² Fermi_GBM
redshift 1.0460 GCN_circulars,Optical
T100 0.439 s
GBM_located False
mjd 59204.96289351852 GCN_circulars,Swift Det
Fermi GBM table
GRB_name_Fermi GRB201221963
trigger_name bn201221963
ra 171.0592°
decl 42.1433°
pos_error 4.26e+00°
datum 2020-12-21
t_trigger 23:06:34.327 UTC
T90 0.144 s
T90_error 0.066 s
T90_start 23:06:34.295 UTC
fluence 6.36e-07 erg/cm²
fluence_error 2.36e-08 erg/cm²
flux_1024 5.66e+00 erg/cm²/s
flux_1024_error 2.71e-01 erg/cm²/s
flux_1024_time -4.48e-01 erg/cm²/s
flux_64 4.06e+01 erg/cm²/s
flux_64_error 2.13e+00 erg/cm²/s
IPN table
GRB_name GRB201221D
ra 171.0500°
decl 42.1500°
pos_error 5.00e-02°
redshift 1.0460
Swift table
GRB_name GRB201221D
t_trigger 23:06:34 UTC
ra 171.0590°
decl 42.1435°
pos_error 5.57e-04°
T90 0.16 s
fluence 3.90e-07 erg/cm²
redshift 1.0460
GCN 29112 table
GRB_name GRB201221D
GCN_number 29112
Detection_method Swift Det
t_trigger 23:06:34 UTC
ra 171.0490°
decl 42.1440°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29112 SUBJECT: GRB 201221D: Swift detection of a bright short burst DATE: 20/12/21 23:16:01 GMT FROM: David Palmer at LANL K. L. Page (U Leicester), S. D. Barthelmy (GSFC), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), B. Sbarufatti (PSU), M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 23:06:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 201221D (trigger=1014037). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 171.049, +42.144 which is RA(J2000) = 11h 24m 12s Dec(J2000) = +42d 08' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 0.3 sec. The peak count rate was ~9000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 23:08:01.7 UT, 87.4 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 171.05873, 42.14332 which is equivalent to: RA(J2000) = 11h 24m 14.10s Dec(J2000) = +42d 08' 36.0" with an uncertainty of 5.7 arcseconds (radius, 90% containment). This location is 26 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. No spectrum from the promptly downlinked event data is yet available to determine the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 92 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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/)
GCN 29113 table
GRB_name GRB201221D
GCN_number 29113
Detection_method Swift-XRT Other
ra 171.0587°
decl 42.1438°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29113 SUBJECT: GRB 201221D: Prompt enhanced Swift-XRT position DATE: 20/12/21 23:32:42 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 201221D, we find an enhanced XRT position of the afterglow: RA, Dec: 171.0587, 42.1438 which is equivalent to: RA (J2000) = 11 24 14.09 Dec (J2000) = +42 08 37.5 with an uncertainty of 4.2 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/1014037. Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team.
GCN 29117 table
GRB_name GRB201221D
GCN_number 29117
Detection_method Optical
ra 171.0584°
decl 42.1444°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29117 SUBJECT: GRB 201221D: candidate optical counterpart from the NOT DATE: 20/12/22 01:34:37 GMT FROM: Daniele B Malesani at DTU Space D. B. Malesani (DTU Space) and E. Knudstrup (NOT and Aarhus Univ.) report on behalf of a larger collaboration: We observed the field of GRB 201221D (Page et al., GCN 29112) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC imaging camera. Observations were carried out using the SDSS r (3x300 s) and z (5x200 s) filters. The data were taken as soon as the target rised, so at quite high airmass (2.9 to 2.3), yielding a seeing of ~1.5". Inside or close to the XRT werror circle (current uncertainty 4.2": https://www.swift.ac.uk/xrt_positions/), a very faint object is detected in the stack of the r-band images. Calibrating against nearby stars from the Pan-STARRS catalog, we measure r = 23.1 +- 0.3 (AB), at a mean epoch 2020 Dec 22.032 UT (1.67 hr after the GRB). Its coordinates are: RA = 11:24:14.02 Dec = +42:08:39.97 No object is visible at this location in the Pan-STARRS r-band image, which has however a limiting magnitude (r ~ 23.3 AB) comparable to our measurement. Given the lack of variability and the still relatively large XRT error circle size, we cannot confirm at the present time whether this object is associated with GRB 201221D. Further observations are planned.
GCN 29118 table
GRB_name GRB201221D
GCN_number 29118
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29118 SUBJECT: GRB 201221D: Nanshan/NEXT early optical upper limit DATE: 20/12/22 01:38:32 GMT FROM: Dong Xu at NAOC/CAS D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report: We observed the field of GRB 201221D (Page et al., GCN 29112) using the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. Observations automatically started at 23:07:39 UT on 2020-12-21, i.e., 65 s after the BAT trigger. We obtained 3x40s, 4x60s and 12x90s frames in the Sloan r-filter. No optical source is detected in our stacked image at the XRT enhanced position (Evans et al., GCN 29113), down to a upper limit of r~21.3, calibrated with the nearby PanSTARRS field.
GCN 29119 table
GRB_name GRB201221D
GCN_number 29119
Detection_method Swift-XRT Det
ra 171.0591°
decl 42.1432°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29119 SUBJECT: GRB 201221D: Enhanced Swift-XRT position DATE: 20/12/22 01:46:49 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 651 s of XRT Photon Counting mode data and 1 UVOT images for GRB 201221D, 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 = 171.05914, +42.14319 which is equivalent to: RA (J2000): 11h 24m 14.19s Dec (J2000): +42d 08' 35.5" with an uncertainty of 3.9 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.
GCN 29122 table
GRB_name GRB201221D
GCN_number 29122
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 29122 SUBJECT: Swift GRB 201221D: Global MASTER-Net observations report DATE: 20/12/22 08:54:08 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (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 201221D ( K. L. Page et al., GCN 29112) errorbox 33444 sec after notice time and 33517 sec after trigger time at 2020-12-22 08:25:12 UT, with upper limit up to 17.5 mag. Observations started at twilight. The observations began at zenith distance = 75 deg. The sun altitude is -12.3 deg. The galactic latitude b = 67 deg., longitude l = 167 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1508187 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 33608 | MASTER-OAFA | C | 180 | 17.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.
GCN 29124 table
GRB_name GRB201221D
GCN_number 29124
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 29124 SUBJECT: GRB 201221D: Swift-XRT refined Analysis DATE: 20/12/22 09:36:27 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), J. D. Gropp (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U. Leicester) and K.L. Page report on behalf of the Swift-XRT team: We have analysed 6.7 ks of XRT data for GRB 201221D (Page et al. GCN Circ. 29112), from 96 s to 23.5 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 29113). The source is fading with alpha >0.4. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01014037. This circular is an official product of the Swift-XRT team.
GCN 29125 table
GRB_name GRB201221D
GCN_number 29125
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29125 SUBJECT: GRB 201221D: FRAM-ORM optical limit DATE: 20/12/22 10:25:06 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 Swift alert of GRB201221D (Page et al., GCNC 29112 and Evans et al. GCNC 29113, GCNC 29119 and 29124), obtaining a series of 20s unfiltered images starting at 23:07:11.9 UT, i.e. 37.6s post trigger. We do not detect any new or strongly variable source neither in single images (detection limit R>~16.9) nor in a combined 40x20s frame (mean exp time 560s post trigger, with a limit R>~18.5). While we analysed the entire 25'x25' field of view centred at the XRT localization, we did pay a special attention to the location of the candidate afterglow mentioned by Malesani & Knudstrup (GCNC 29117) with a negative outcome.
GCN 29128 table
GRB_name GRB201221D
GCN_number 29128
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29128 SUBJECT: GRB 201221D: Lowell Discovery Telescope afterglow observations DATE: 20/12/22 12:59:55 GMT FROM: Simone Dichiara at UMCP/NASA/GSFC S.Dichiara (UMD, NASA-GSFC), E. Troja (UMD, NASA-GSFC), S.B. Cenko (NASA-GSFC), B. O'Connor (GWU, UMD), P. Gatkine (Caltech), J.M. Durbak (UMD), A. Kutyrev (UMD, NASA-GSFC), S. Veilleux (UMD), report on behalf of a larger collaboration: We observed the short GRB 201221D (Page et al., GCN 29112) using the Large Monolithic Imager (LMI) on the 4.3m Lowell Discovery Telescope (LDT) at Happy Jack, AZ. Observations started on December 22, at 09:13:28 UT (about 10.11 hours after the Swift trigger) with SDSS r, i and z filters. Observations were taken at an airmass of about 1.3 and seeing of about 0.8". At the position of the optical candidate counterpart (Malesani et al., GCN 29117) we detect a source in all bands with r~23.9 AB mag and i~23.7 AB mag. This is fainter than the value reported by Malesani et al. (r~23.1 at 1 hr) and may suggest that the source faded between the two epochs. However, we note that at the same position a weak source is visible in archival Pan-STARRS images, which we suggest as the putative GRB host galaxy. Our observations could be dominated by the galaxy's contribution, and further observations to determine variability are planned. We thank the staff of the Lowell Discovery Telescope for assistance with these observations.
GCN 29129 table
GRB_name GRB201221D
GCN_number 29129
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 29129 SUBJECT: GRB 201221D: Swift/UVOT Upper Limits DATE: 20/12/22 13:27:07 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 201221D 92 s after the BAT trigger (Page et al., GCN Circ. 29112). No optical afterglow consistent with the NOT or XRT position (Malesani et al. GCN Circ. 29117; Evans et al. GCN Circ. 29119) 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 92 242 147 >20.3 u_FC 305 554 246 >19.3 white 4047 4247 197 >21.0 v 634 4657 216 >19.2 u 305 5110 282 >19.4 w1 684 5068 216 >19.7 m2 4663 4863 197 >19.5 w2 4253 4453 197 >19.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
GCN 29130 table
GRB_name GRB201221D
GCN_number 29130
Detection_method Konus-Wind Det
t_trigger 23:06:37.636 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 29130 SUBJECT: Konus-Wind detection of GRB 201221D (short) DATE: 20/12/22 13:33:30 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 short GRB 201221D (Swift detection: Page et al., GCN 29112) triggered Konus-Wind (KW) at T0=83197.636 s UT (23:06:37.636). The burst light curve shows a single pulse with the total duration of ~1.9 s (20-1500 keV). The emission is seen up to ~1 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB201221_T83197/ As observed by Konus-Wind, the burst had a fluence of (5.3 ± 1.1)x10^-7 erg/cm^2 and a 16-ms peak energy flux, measured from T0-0.016 s, of (6.6 ± 1.3)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The spectrum of the burst (measured from T0 to T0+0.128 s) is best fit 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) with alpha = -0.95(-0.52,+0.64) and Ep = 148(-37,+86) keV (chi2 = 19/20 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.1 (chi2 =19/19 dof). All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.
GCN 29132 table
GRB_name GRB201221D
GCN_number 29132
Detection_method Optical
redshift 1.0460
Circular_text TITLE: GCN CIRCULAR NUMBER: 29132 SUBJECT: Short GRB201221D: High Redshift from OSIRIS/GTC DATE: 20/12/22 14:49:53 GMT FROM: Alexander Kann at IAA-CSIC A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann (HETH/IAA-CSIC), L. Izzo (DARK/NBI), C.C. Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC) and G. Lombardi (GRANTECAN, IAC) report: We obtained spectroscopy of the optical counterpart (Malesani et al., GCN #29117) of the short GRB 201221D (Page et al., GCN #29112) with OSIRIS at the 10.4m Gran Telescopio Canarias (Roque de los Muchachos Observatory, La Palma, Spain), starting at 1:52 UT (2.757 hr after the burst). The observation consisted of 4 x 1200 s exposures with the R1000B grism, covering the range between 3700 and 7800 Angstrom. The spectrum shows a weak continuum over the full spectral range. There is a prominent emission feature that we identify as the [OII] 3727/3729 doublet at a redshift of 1.046. This line happens to lie in the atmospheric A band, and therefore must be quite strong to be detectable. There are also low significance absorption featuress coincident with FeII and MgII at a similar redshift (z = 1.045). We identify this as the redshift of GRB 201221D. We note this is a high redshift for a short GRB, and it represents one of the few short GRB spectra to show afterglow absorption features.
GCN 29133 table
GRB_name GRB201221D
GCN_number 29133
Detection_method Optical
ra 171.0584°
decl 42.1444°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29133 SUBJECT: GRB 201221D: Archival PS1 Imaging of the Putative Host Galaxy DATE: 20/12/22 15:34:10 GMT FROM: Charles Kilpatrick at UC Santa Cruz C. D. Kilpatrick (Northwestern), D. B. Malesani (DTU Space), and W. Fong (Northwestern), report: “We analyzed stacked images from the PS1 Data Release 1 image archive (Flewelling et al., 2016, arXiv:1612.05243) of the location of the short-duration GRB 201221D (Page et al., GCN 29112). We detected a single source centered at: RA (J2000): 11:24:14.01 Dec (J2000): +42:08:39.69 in PS1 g-band, 4.6 arcseconds from the latest enhanced XRT position of GRB 201221D (Evans et al., GCN 29119). We note that this places the centroid of the candidate host galaxy just outside the enhanced XRT error circle reported by GCN 29119, which has a radius of 3.9 arcsec (90% confidence), although consistent with the real-time XRT error circle at https://www.swift.ac.uk/xrt_positions/01014037/ . Performing forced aperture photometry on this position with an aperture fixed to the FWHM size in all PS1 bands (approximately 1.1 arcseconds), we found that this source has a brightness: g = 23.2 +/- 0.2 mag r > 23.2 mag i > 23.3 mag z > 22.2 mag y = 22.6+/-0.2 mag All magnitudes are given in AB. We note that this source is coincident with emission identified in Malesani & Knudstrup (GCN 29117) who find a source with r = 23.1+/-0.3 mag (AB) in NOT follow up imaging. Similarly, Dichiara et al. (GCN 29128) find r=23.9 mag and i=23.7 mag (AB), all of which are consistent with our limiting magnitudes. Based on this photometry, it is fully plausible that the reported optical candidate (GCN 29117, GCN 29128) is dominated by the host galaxy. However, the detection of absorption features in the spectrum (de Ugarte Postigo et al., GCN 29132), coupled with the possible r-band fading between NOT and DCT observations (reported in GCN 29128) may indicate the presence of an optical afterglow on top of the host emission. Image subtraction will be required to test for fading, and further, deep optical observations are encouraged.
GCN 29139 table
GRB_name GRB201221D
GCN_number 29139
Detection_method Swift-BAT Det
ra 171.0550°
decl 42.1520°
Circular_text TITLE: GCN CIRCULAR NUMBER: 29139 SUBJECT: GRB 201221D: Swift-BAT refined analysis DATE: 20/12/22 17:44:15 GMT FROM: Amy Lien at GSFC H. A. Krimm (NSF), S. D. Barthelmy (GSFC), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 201221D (trigger #1014037) (Page et al., GCN Circ. 29112). The BAT ground-calculated position is RA, Dec = 171.055, 42.152 deg which is RA(J2000) = 11h 24m 13.2s Dec(J2000) = +42d 09' 08.4" with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 23%. The mask-weighted light curve shows a single-peaked structure that starts at ~T-0.06 s, peaks at ~T+0.02 s, and ends at ~T+0.2 s. T90 (15-350 keV) is 0.16 +- 0.04 sec (estimated error including systematics). The time-averaged spectrum from T-0.06 to T+0.17 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.56 +- 0.13. The fluence in the 15-150 keV band is 3.9 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band is 5.6 +- 0.5 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/1014037/BA/
GCN 29140 table
GRB_name GRB201221D
GCN_number 29140
Detection_method Fermi GBM Det
t_trigger 23:06:34.330 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 29140 SUBJECT: GRB 201221D: Fermi GBM detection DATE: 20/12/22 18:52:47 GMT FROM: Rachel Hamburg at UAH R. Hamburg (UAH), C. Malacaria (NASA-MSFC/USRA), and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 23:06:34.33 UT on 21 December 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 201221D (trigger 630284799 / 201221963) which was also detected by the Swift/BAT and Swift/XRT (Page et al. 2020, GCN 29112) and Konus-Wind (Frederiks et al. 2020, GCN 29130). This trigger was initially classified as a particle event by the flight software, but is in fact a GRB. The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 89 degrees. The GBM light curve shows a single-peaked structure with a duration (T90) of about 0.14 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.192 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.20 +/- 0.16 and the cutoff energy, parameterized as Epeak, is 108 +/- 5 keV. A Band function fits the spectrum equally well with Epeak = 98 +/- 8 keV, alpha = 0.01 +/- 0.24 and beta = -3.3 +/- 0.5. The event fluence (10-1000 keV) in this time interval is (1.076 +/- 0.046)E-06 erg/cm^2. The 64-ms peak photon flux measured starting from T0+0.00 s in the 10-1000 keV band is 41 +/- 2 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/"
GCN 29141 table
GRB_name GRB201221D
GCN_number 29141
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 29141 SUBJECT: GRB 201221D: LCOGT upper limits DATE: 20/12/22 19:18:16 GMT FROM: Igor Andreoni at Caltech Igor Andreoni (Caltech), Michael M. Coughlin (UMN) on behalf of the Global Relay of Observatories Watching Transients Happen (GROWTH) collaboration We used the Sinistro camera on the 1-m LCO Global Telescope Network (LCOGT, Brown et al., 2013) to observe the afterglow of short-duration GRB 201221D (Page et al., GCN #29112). Two sets of 300s exposures were acquired in g-r-i bands between 2020-12-22T07:57 and 2020-12-22T08:47 UTC. The observations were performed under proposal IDs TOM2020A-008 (PI Andreoni) and NOAO2020B-005 (PI Coughlin). We do not identify any source within 3.9 arcsec of the enhanced Swift-XRT position (Evans et al., GCN #29119). Photometric upper limits, calibrated against Pan-STARRS DR1 magnitudes (Chambers et al., 2016), were measured to be g > 22.8, r > 22.2, and i > 21.5 mag (5-sigma) after image stacking. The candidate optical counterpart (transient or host galaxy: Malesani et al., GCN #29117; Dichiara et al., GCN #29128; de Ugarte Postigo et al., GCN #29132; Kilpatrick et al., GCN #29133) is too faint to be detectable in our observations, which did not show any significant brightening, as expected. We thank the TOM Community Development Program and the TOM Toolkit Workshop organizers for the generous LCOGT time allocation. GROWTH is a worldwide collaboration comprising Caltech, USA; IPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan; IIT-B, India; IIA, India; LJMU, TTU, USyd, Australia, and SDSU, USA. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949.
GCN 29142 table
GRB_name GRB201221D
GCN_number 29142
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29142 SUBJECT: GRB 201221D: MMT MMIRS detection of marginally extended source DATE: 20/12/22 22:39:03 GMT FROM: Jillian Rastinejad at Northwestern Univ. J. Rastinejad, K. Paterson, C. D. Kilpatrick, W. Fong (Northwestern) report: We observed the location of the Swift GRB 201221D (Page et al., GCN 29112) with the MMT and Magellan Infrared Spectrograph (MMIRS) mounted on the MMT 6.5-meter telescope on Mount Hopkins, Arizona. We obtained 25x60-sec imaging in J-band at a mid-time of 2020 December 22.36 UT (0.40 days post-burst). Within the vicinity of the XRT position (Evans et al., GCN 29113; Evans et al., GCN 29119), we detect a marginally extended source, consistent with the location of emission detected in previously reported optical follow up and archival imaging (Malesani et al., GCN 29117; Dichiara et al., GCN 29128; de Ugarte Postigo et al., GCN 29132; Kilpatrick et al., GCN 29133). After calibrating our stacked image to isolated stars detected in the 2MASS photometric catalog (Cutri et al., 2003, NASA/IPAC), we applied a 3 arcsecond aperture and measure a magnitude of J = 21.8 +/- 0.2 mag (AB and not corrected for Milky Way extinction). Further observations are planned to assess any variability of the source. We thank Ryan Howie and Joannah Hinz at the MMT for the rapid scheduling and execution of these observations.
GCN 29144 table
GRB_name GRB201221D
GCN_number 29144
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29144 SUBJECT: GRB 201221D: SMA submm observation DATE: 20/12/23 02:49:57 GMT FROM: Yuji Urata at Nat. Central U. Huang, K. (CYCU), Urata, Y. (NCU) and Petitpas, G (SAO). report: We observed the field of the GRB201221D (Page et al., GCN #29112) at 228 GHz using the Submillimeter Array (SMA). The observation was started at 2020 December 11:27 UT (12.3 h after the burst). There was no source at the candidate of optical afterglow (Malesani et al., GCN #29117; Dichiara et al., GCN #29128; de Ugarte Postigo et al., GCN #29132; Kilpatrick et al., GCN #29133; Rastinejad et al. GCN #29142). The preliminary limit of the observation is ~0.2 mJy (rms). We thank Ramprasad Rao, Mark Gurwell and staff of SMA for the scheduling and execution of observations.
GCN 29148 table
GRB_name GRB201221D
GCN_number 29148
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29148 SUBJECT: GRB 201221D: 3.6m DOT optical observations DATE: 20/12/23 12:27:46 GMT FROM: Rahul Gupta at ARIES, India Dimple (ARIES), A. Panchal (ARIES), A. Gangopadhyay (ARIES), A. Ghosh (ARIES), R. Gupta (ARIES), A. Kumar (ARIES), K. Misra (ARIES), and S. B. Pandey (ARIES) report: We carried out the follow-up observations of GRB 201221D (Page et al., GCN 29112) with Aries Devasthal Faint Object Spectrograph and Camera (ADFOSC) mounted on the 3.6m Devasthal Optical Telescope (DOT) at Devasthal observatory of Aryabhatta Research Institute of observational sciencES (ARIES), India. The observations were started on 2020-12-22 at 23:10:00 UT. We observed a series of 4 images with the exposure time of 900 seconds each in r-band. At the position reported by Malesani et al., (GCN 29117), we detect an uncatalogued source in r-band with a magnitude of 23.46 +- 0.09 (AB mag), calibrated with the nearby PanSTARRS field. However, we remark that this is an extended source and may contain significant host galaxy contribution. For further verification, host galaxy subtraction is highly encouraged. The magnitude is not corrected for the Galactic extinction in the direction of the burst. This circular may be cited.
GCN 29311 table
GRB_name GRB201221D
GCN_number 29311
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 29311 SUBJECT: GRB 201221D: near-infrared observation with LBT DATE: 21/01/17 15:18:45 GMT FROM: Andrea Rossi at INAF A. Rossi (INAF-OAS) reports on behalf of the CIBO collaboration: We observed the location of the optical afterglow (Malesani et al., GCN 29117) of the short GRB 201221D (Page et al., GCN 29112) simultaneously in the J and Ks bands with the LUCI near-infrared imager and spectrograph mounted on the Large Binocular Telescope (LBT, Mt Graham, AZ, USA). Observations were obtained on 2020-12-24 at the UT midtime 11:40:00, i.e. ~2.5 days after the burst trigger, for a total of 20 min of exposure in each band. Inspection of the combined J and K-band images reveals a faint, extended source in both filters, for which we preliminary measure J=21.7+-0.3 (Vega system), calibrated against 2MASS field stars. We acknowledge the excellent support from the LBTO and LBT-INAF staff, particularly A. Cardwell, F. Cusano, and D. Paris, in obtaining these observations.