GRB 201216C
GCN Circular 29061
Subject
GRB 201216C: Swift detection of a burst
Date
2020-12-16T23:15:47Z (4 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
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/)
GCN Circular 29063
Subject
GRB 201216C: Fermi GBM Final Real-time Localization
Date
2020-12-16T23:17:45Z (4 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
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
GCN Circular 29064
Subject
GRB 201216C: Swift-XRT observations
Date
2020-12-17T00:58:40Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
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).
GCN Circular 29066
Subject
GRB 201216C: VLT afterglow candidate discovery
Date
2020-12-17T02:36:55Z (4 years ago)
From
Luca Izzo at DARK/NBI <luca.izzo@gmail.com>
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.
GCN Circular 29067
Subject
GRB 201216C: Enhanced Swift-XRT position
Date
2020-12-17T05:30:00Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
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.
GCN Circular 29070
Subject
GRB 201216C: FRAM-ORM afterglow confirmation
Date
2020-12-17T11:16:09Z (4 years ago)
From
Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek@asu.cas.cz>
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.
GCN Circular 29071
Subject
GRB 201216C: Swift/UVOT Upper Limits
Date
2020-12-17T11:19:46Z (4 years ago)
From
Samantha Oates at MSSL <samantha.oates@alumni.ucl.ac.uk>
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).
GCN Circular 29073
Subject
GRB 201216C: Fermi GBM detection
Date
2020-12-17T15:03:27Z (4 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
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/"
GCN Circular 29074
Subject
GRB 201216C: AstroSat CZTI detection
Date
2020-12-17T15:10:28Z (4 years ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar24@gmail.com>
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.
GCN Circular 29075
Subject
GRB 201216C: MAGIC detection in very high energy gamma rays
Date
2020-12-17T17:23:13Z (4 years ago)
From
Oscar Blanch at MAGIC Collaboration <blanch@ifae.es>
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.
--
Av�s -
Aviso - Legal Notice - (LOPD) - http://legal.ifae.es
<http://legal.ifae.es/>
GCN Circular 29076
Subject
GRB 201216C: Fermi-LAT upper limit
Date
2020-12-17T19:15:12Z (4 years ago)
From
Elisabetta Bissaldi at INFN,Bari <elisabetta.bissaldi@ba.infn.it>
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.
GCN Circular 29077
Subject
GRB 201216C: VLT X-shooter spectroscopy and potential high redshift of a VHE-emitting GRB
Date
2020-12-17T22:12:41Z (4 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
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.
GCN Circular 29080
Subject
GRB 201216C: Swift-BAT refined analysis
Date
2020-12-18T02:04:50Z (4 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
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/
GCN Circular 29084
Subject
Konus-Wind detection of GRB 201216C
Date
2020-12-18T14:50:32Z (4 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
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.
GCN Circular 29085
Subject
GRB 201216C: Liverpool Telescope First Hour Observations
Date
2020-12-18T14:51:28Z (4 years ago)
From
Manisha Shrestha at Liverpool John Moores U <m.shrestha@ljmu.ac.uk>
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.
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GCN Circular 29086
Subject
GRB201216C: No significant detection in HAWC
Date
2020-12-18T17:04:28Z (4 years ago)
From
Hugo Ayala at Pennsylvania State University <hgayala@psu.edu>
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.
GCN Circular 29210
Subject
GRB 201216C: TSHAO, Terskol, Mondy optical upper limits
Date
2020-12-31T17:43:53Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
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
GCN Circular 29278
Subject
GRB 201216C: Swift-XRT refined Analysis
Date
2021-01-08T02:49:56Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
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.
GCN Circular 29280
Subject
Correction to GCN 29278: GRB 201216C XRT refined analysis
Date
2021-01-08T11:59:30Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
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.
GCN Circular 29674
Subject
GRB 201216C: VIRT optical observations
Date
2021-03-19T23:01:33Z (4 years ago)
From
Priyadarshini Gokuldass at U. of the Virgin Islands <priyadass.94@gmail.com>
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.