GRB 161219B
GCN Circular 22608
Subject
Chandra observations of GRB161219B 400 days after the explosion
Date
2018-04-06T02:38:08Z (8 years ago)
From
Aprajita Hajela at Northwestern U <AprajitaHajela2015@u.northwestern.edu>
A. Hajela, R. Margutti (Northwestern University), C. Guidorzi (U Ferrara),
A. Kamble (Harvard), A. MacFadyen (NYU), D. Milisavljevic (Purdue), J.
Parrent (Harvard), A. Zauderer (NSF) report:
"We started deep X-ray follow-up observations of GRB161219B with the
Chandra X-ray Observatory on 2017, August 8 UT (dt ~ 232 days after
explosion, exposure time of 15 ks), PI Margutti, program 18500396. An X-ray
source is detected at the location of GRB161219B with count-rate of ~
0.0024 cts/s (0.5 - 8 keV) and significance of 16 - sigma. The spectrum is
well modeled with an absorbed simple power law with best-fitting photon
index, Gamma = 1.95 +/- 0.38 and Galactic absorption, N_h = 2.8e+20 cm-2.
We do not find any evidence of intrinsic absorption. For these parameters,
the unabsorbed flux is (3.41 +/- 0.76) x 10^-14 ergs cm-2 s-1 (0.3 - 10
keV).
A second Chandra observation was acquired between 2018, January 16th and
January 18th (dt ~ 393-395 days since explosion, exposure time of 32 ks).
GRB161219B is detected with the count-rate of ~ 0.0013 cts/s (0.5 - 8 keV)
and a significance of 9 -sigma. The best-fitting photon-index is Gamma =
2.05 +/- 0.34 . The corresponding unabsorbed flux is (1.72 +/- 0.28) x
10^-14 ergs cm-2 s-1 (0.3 - 10 keV).
We find that GRB161219B continues to decay following a power-law with
index, alpha = 1.22 +/- 0.04 , which is consistent with the decay
inferred from XRT data at t < 115 days.
We thank the entire Chandra team for making these observations possible."
[GCN OPS NOTE(06apr18): Per author's request, the last two paragraphs
were added.]
GCN Circular 20442
Subject
GRB 161219B: afterglow and SN2016jca optical observations
Date
2017-01-12T17:57:30Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), E. Mazaeva (IKI), R. Inasaridze (AbAO), A. Moskvitin (SAO
RAS), E. Klunko (ISTP), V. Rumyantsev (CrAO), I. Korobtsev (ISTP), V.
Ayvazian (AbAO), O. Kvaratskhelia (AbAO), G. Inasaridze (AbAO), I.
Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB
follow-up collaboration:
We observed the field of GRB 161219B (Swift trigger 727541; D'Ai,GCN 20296)
with AZT-33IK (Mondy), ZTSh (CrAO), AS-32 (AbAO) and Zeiss-1000 (SAO RAS)
telescopes. We obtained unfiltered images (AbAO) and images in R-filter
(other observatories). The optical source associated with the afterglow
(D'Ai et al., GCN 20296; Kruehler et al., GCN 20299; Guidorzi et al., GCN
20300; Martin-Carrillo et al., GCN 20305) and SN2016jca (de Ugarte Postigo
et al., GCN 20342; Chen et al., GCN 20380) is clearly visible in all our
observations.
Preliminary light curve of the afterglow and SN2016jca can be found at
http://grb.rssi.ru/GRB161219B/GRB161219B_LC.png
Photometry is based on nearby USNO-B1.0 stars (R2) common for all images.
Late time photometry is contaminated by Pan-STARRS galaxy previously
reported by Kruehler et al. (GCN 20299), and also presented in USNO-B1.0.
Apparent maximum brightness of the SN2016jca was observed at about 11 days
after burst onset (R = 19.2 at 2016-12-30 (UT) 20:04:59) and actual SN peak
could be slighter later, between 11 and 14 days after burst.
GCN Circular 20380
Subject
PESSTO follow-up of GRB 161219B/SN2016jca
Date
2017-01-06T11:08:31Z (9 years ago)
From
Ting-Wan Chen at MPE <jchen@mpe.mpg.de>
T.-W. Chen (MPE), J. Greiner (MPE), S. Klose (TLS), K. W. Smith (QUB), A. Cikota (ESO), M. Magee (QUB), C. Inserra (QUB), J. Lyman (Univ. of Warwick), E. Kankare (QUB), K. Maguire (QUB), S. J. Smartt (QUB), M. Sullivan (Southampton), S. Valenti (UC Davis), O. Yaron (Weizmann), D. Young (QUB), and I. Manulis (Weizmann) report:
We acquired spectroscopic followup of SN2016jca (de Ugarte Postigo et al., GCN 20342; Pian et al. on Transient Name Server <https://wis-tns.weizmann.ac.il/object/2016jca <https://wis-tns.weizmann.ac.il/object/2016jca>>), the SN associated with GRB 161219B (D'Ai et al. GCN 20296), using the ESO New Technology Telescope at La Silla at 04:48 UT on 2017-01-04 (15.4 days after the GRB trigger) with EFOSC2 and Grism 13 (3985-9315A, 18A resolution) in the framework of the PESSTO, the Public ESO Spectroscopic Survey for Transient Objects (see Smartt et al. 2015, A&A, 579, 40 <http://www.pessto.org <http://www.pessto.org/>>).
The spectrum shows several broad emission features and a significant decrease in flux toward both the blue and red ends, as a broad-line Type Ic supernova around the maximum light. A good match is achieved with SN1998bw at +1.3d using GELATO (Harutyunyan et al., 2008, A&A, 488, 383) and also with SN2002ap at -2d using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).
GCN Circular 20346
Subject
GRB161219B - Anticipated hyperluminal evidence
Date
2016-12-29T07:49:28Z (9 years ago)
From
Arnon Dar at Technion-Israel Inst. of Tech <arnon@physics.technion.ac.il>
S. Dado, A. Dar and A. De Rujula report:
High resolution VLA/VLBI follow-up observations of the radio
afterglow of GRB161219B [1,2] may provide direct measurements
of the hyperluminal motion and of the initial Lorentz factor of
the afterglow's source, relative to its parent supernova [3].
The small isotropic energy Eiso~1.6xE52 erg and the peak energy
E'p~104 keV of the relatively nearby GRB161219B measured by Konus-
Wind [4] indicate, in the cannonball model of GRBs, that this is
an ordinary GRB viewed far off-axis [5]. In this model ordinary
GRBs viewed on or near the axis of their relativistic ejecta
satisfy E'p~150 (Eiso/E52)^{1/2} keV. The Konus-Wind measurements
imply [5] a viewing angle @~3/Gamma and a linear polarization
P = 2 @^2 Gamma^2/(1+@^4 Gamma^4)~20% where Gamma is the bulk-motion
Lorentz factor of the jet which produced GRB161219B in a broad-line
Ic supernova explosion akin to that of SN1998bw [3].
The bright radio afterglow of the relatively nearby GRB161219B [1,2]
at redshift z=0.1475 [6] provides an excellent opportunity to measure
the apparent superluminal speed V of its jet in the plane of the sky.
As long as @^2 x Gamma^2 >> 1, V=2c/(1+z)@ and a measurement of V yields
Gamma~3(1+z)V/2. If the jet decelerates in a constant density environment
and reaches @^2 x Gamma^2 << 1 before its superluminal speed could be
measured, then its late-time apparent superluminal speed in the plane of
the sky, which is expected to decrease like t^{-1/2), if measured,
may be extrapolated to obtain an estimate of Gamma at early time [5].
[1] K. D. Alexander, et al. GCN 20313
[2] A. J. Nayana & and P. Chandra, GCN 20344
[3] A. de Ugarte Postigo, et al. GCN 20342
[4] D. Frederiks, T. Laskar, E. Berger, GCN 20323
[5] S. Dado, A. Dar, A. De Rujula, arXiv:1610.01985
[6] N. R. Tanvir, et al. GCN 20321
[GCN OPS NOTE(29dec16): The suffix "B" was added to the GRB name
in the SUBJECT-line.]
GCN Circular 20344
Subject
GMRT radio detection of GRB 161219B
Date
2016-12-27T16:44:35Z (9 years ago)
From
Nayana A J at NCRA-TIFR <nayan89deva@gmail.com>
A. J. Nayana (NCRA-TIFR) and Poonam Chandra (NCRA-TIFR) reports:
We carried out Giant Metrewave Radio Telescope (GMRT) observations of
GRB 161219B (D'Ai et al. GCN Circ. 20296) in the 1390 MHz band on 2016
Dec 26.68 UT. We
detect the radio afterglow of the GRB in the Swift error circle
(Beardmore et al. GCN
Circ. 20297). The 1390 MHz band flux density of the afterglow is
397+/-55 uJy. Map rms is
40 uJy/beam.
Further observations are planned. We thank GMRT staff for making these
observations possible.
GCN Circular 20342
Subject
GRB 161219B: Spectroscopic detection of the associated SN with OSIRIS/GTC
Date
2016-12-27T11:13:04Z (9 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), Z. Cano, L. Izzo,
C. Thoene, R. Sanchez-Ramirez, K. Bensch (IAA-CSIC), D. A. Kann
(IAA-CSIC, TLS), N. Tanvir (U. Leicester), S. Schulze, G. Leloudas
(Weizmann Institute), S. Geier (IAC, GRANTECAN), A. Tejero
(GRANTECAN) report on behalf of a larger collaboration:
We observed the optical counterpart of GRB 161219B (D���Ai et al. GCN
20296) with OSIRIS at the 10.4m GTC telescope on La Palma (Spain).
The observations consisted of 3 x 900 s spectra using grism R1000B,
which covers the spectral region between 3700 and 7800 AA, plus g, r, i
and z-band imaging. The point-like GRB counterpart is prominent on top
of the elongated host galaxy.
The combined spectrum has mean UT epoch on 27.02 December (7.24
days after the burst) and shows a strong continuum with clear broad
features typical of a type Ic-BL supernova, implying that the supernova
contribution is already significant. We also detect several emission
features of the host galaxy (due to [OIII], [OII], [NII] and H) as well as CaII
in absorption at the redshift of z = 0.1475 proposed for the GRB (Tanvir
et al. GCN 20321).
GCN Circular 20332
Subject
GRB 161219B: UKIRT near-IR afterglow detection
Date
2016-12-22T23:40:43Z (9 years ago)
From
Wen-fai Fong at U of Arizona <wfong@email.arizona.edu>
W. Fong and P. Milne (University of Arizona) report:
"We observed the field of the long-duration GRB 161219B (D'Ai et al., GCN
20296) with the Wide Field Camera (WFCAM) mounted on the 3.8-m United
Kingdom Infrared Telescope (UKIRT) on Mauna Kea beginning on 2016 Dec
22.368 UT (2.58 days post-burst). We obtained observations in the J-, H-
and K-bands in 0.72" seeing. Using the quick-look pipeline ORAC-DR, we
detect the near-IR afterglow in coincidence with the X-ray (Beardmore et
al., GCN 20297), optical (Kruehler et al., GCN 20299; Guidorzi et al., GCN
20300; Martin-Carrillo et al., GCN 20305; Marshall et al., GCN 20306;
Mazaeva et al., GCN 20309; Buckley et al., GCN 20322), and radio (Alexander
et al., GCN 20313; Laskar et al., GCN 20328) afterglows. Calibrated to
2MASS, we estimate a preliminary brightness of J(AB)=18.8 +/- 0.1 mag for
the near-IR afterglow of GRB 161219B. Further observations are planned.
We thank Watson Varricatt and Sam Benigni for their assistance in planning
and executing these observations."
GCN Circular 20331
Subject
GRB 161219B: POLAR Observation
Date
2016-12-22T10:38:13Z (9 years ago)
From
Haulin Xiao at PSI/POLAR <hualin.xiao@psi.ch>
Hualin Xiao (PSI), Wojtek Hajdas (PSI) and Radek Marcinkowski (PSI) report on behalf of the POLAR collaboration:
At 2016-12-19T18:48:39.0 UT(T0), during a routine on-ground search of data, POLAR detected the GRB 161219B,
which was also observed by Swift BAT (trigger #727541).
The POLAR light curve consists of one peak with duration (T90) of 4.0 +- 0.5 s measured from T0.
The 0.5 s peak flux at T0+1.75 s is equal to 248 +-44 cnts/sec.
Above measurements are in the energy range of about 80 - 500 keV.
LC_URL: http://polar.psi.ch/triggers/GRB161219B.png
and http://polar.psi.ch/pub/lc.php?event=GRB+161219B
Using the best location from the Swift BAT, which is (J2000):
RA: 91.717 [deg]
Dec: -26.790 [deg]
the incident angle in the POLAR coordinate at T0 is:
Theta: 96.6 [deg]
Phi: 201.2 [deg]
The analysis results presented above are preliminary. Calibration of the instrument is ongoing.
POLAR is a dedicated Gamma-Ray Burst polarimeter which was launched on-board the Chinese space
laboratory Tiangong-2 (TG-2) on Sep 15, 2016. The energy detection range of POLAR is ~ 50-500 keV.
More information about POLAR can be found at http://polar.psi.ch/pub , http://polar.ihep.ac.cn/en/ and http://isdc.unige.ch/polar/ .
This message is quotable in publications.
GCN Circular 20328
Subject
GRB 161219B: Rapid ALMA Observations & Detection
Date
2016-12-22T00:08:08Z (9 years ago)
From
Tanmoy Laskar at UC Berkeley <tanmoylaskar@gmail.com>
T. Laskar (NRAO / UC Berkeley), K. D. Alexander (Harvard), and E. Berger
(Harvard) report on behalf of a larger collaboration:
We observed the Swift GRB 161219B (D���Ai et al. GCN 20296) at 3 mm with the
Atacama Large Millimeter/submillimeter Array (ALMA) beginning 2016 December
21.08 UT (1.30 days after the burst). At a mean frequency of 97 GHz, we
detect a radio source with a preliminary flux density of ~ 1 mJy at
RA (J2000) = 06:06:51.429 +/- 0.001
Dec (J2000) = -26:47:29.62 +/- 0.01
consistent with the position of the optical afterglow, the refined
Swift/XRT position (Beardmore et al. GCN 20297), and the radio afterglow
(Alexander et al. GCN 20313). Follow-up observations are planned.
We thank the JAO staff for rapidly executing these observations.
GCN Circular 20327
Subject
Correction to GCN 20323 "Konus-Wind observation of GRB 161219B"
Date
2016-12-21T21:34:19Z (9 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks reports on behalf of the Konus-WIND team:
The first line of GCN 20323 should read:
"The long GRB 161219B (Swift-BAT trigger #727541: D'Ai et al.,",
not " ... GRB 161219A ..."
We thank Sandro Mereghetti for pointing this out and we apologize
for any confusion this may have caused.
GCN Circular 20323
Subject
Konus-Wind observation of GRB 161219B
Date
2016-12-21T17:31:16Z (9 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 161219A (Swift-BAT trigger #727541: D'Ai et al.,
GCN 20296; Palmer et al., GCN 20308; T0(BAT)=18:48:19.308 UT)
was detected by Konus-Wind (KW) in the waiting mode.
The light curve shows a single pulse with a duration of ~10 s.
Modeling the KW 3-channel time-integrated spectrum
(from T0(BAT)-0.134 s to T0(BAT)+8.698 s) by
a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.59 �� 0.71 and Ep = 91 �� 21 keV.
The corresponding 20-1000 keV energy fluence for this
time interval is (3.1 �� 0.8)x10^-6 erg/cm2.
Assuming the redshift z=0.1475 (Tanvir et al., GCN 20321)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the burst isotropic energy release E_iso to ~1.6x10^50 erg
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, to ~104 keV.
The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB161219B/
All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.
GCN Circular 20322
Subject
GRB 161219B: SALT observations
Date
2016-12-21T17:29:49Z (9 years ago)
From
Soebur Razzaque at U of Johannesburg <srazzaque@uj.ac.za>
D.A.H. Buckley (SAAO/SALT), A. Hamanowicz (Warsaw U.), A. Martin-Carrillo (UCD), S. Razzaque (U. Johannesburg), T. Garrigoux (North-West U.), L. Hanlon (UCD), M. M. Kotze (SAAO/SALT) and R. Kuhn (SAAO/SALT) report on behalf of a larger collaboration.
We observed the Swift GRB 161219B (D���Ai et al. GCN 20296) on December 20 using the Southern African Large Telescope (SALT) in Sutherland, South Africa, 24.73 h after the Swift GRB trigger. A 20 s r'-band image was obtained using SALTICAM at 19:32:30 UTC, just prior to the commencement of the spectroscopy, and the optical counterpart reported by D'Ai et al. (GCN 20296), Kruehler et al. (GCN 20299), Guidorzi et al. (GCN 20300), Martin-Carrillo et al. (GCN 20305), Mazaeva et a. (GCN 20309), Tanvir et al. (GCN 20321) was clearly visible in the SALT image.
From photometry of the source and six APASS reference stars in the field, we determined the brightness to be r' = 18.94 +/- 0.06. Spectroscopy with the Robert Stobie Spectrograph (RSS) started at 19:37:39 UTC and ran until 20:27:51 UTC during which two 1500 s spectra were obtained, nominally covering the spectral region from 340 to 1000 nm at a mean resolution of R = 350. The optical spectrum was characterised by a blue continuum and was heavily contaminated by sky emission lines above 850 nm. No obvious spectral faetures were seen in the combined spectrum.
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GCN Circular 20321
Subject
GRB 161219B: VLT/X-shooter redshift
Date
2016-12-21T14:25:47Z (9 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
N. R. Tanvir (U. Leicester), T. Kruehler (MPE), K. Wiersema (U.
Leicester), D. Xu (NAOC/CAS), D. Malesani (DARK/NBI), B. Milvang-Jensen
(DARK/NBI), and J. P. U. Fynbo (DARK/NBI) report on behalf of a larger
collaboration:
We observed the optical counterpart of GRB 161219B (Swift trigger
727541; D'Ai et al., GCN #20296) with the ESO Very Large Telescope UT 2
(Kueyen) equipped with the X-shooter spectrograph, covering the
wavelength range 3200-22000 AA. Observations started at 06:34 UT on
2016-12-21, roughly 36 hr after the burst and consisted of 4 exposures
of 600 s each. We measure r ~ 19.5 mag from the acquisition image.
Our spectrum exhibits absorption features from Mg II, Mg I, Ca H, Ca K,
all at a common redshift of z = 0.1475. We also detect nebular lines
from the Balmer series, [O II] and [O III] at a consistent redshift,
which we conclude is the redshift of the GRB. The emission features are
likely coming from the object visible in the PanSTARRS data, first
noticed by Kruehler et al. (GCN 20299).
We acknowledge excellent support from the ESO observing staff in
Paranal, in particular Julien Milli, Thomas Rivinius, and Dimitri Gadotti.
GCN Circular 20314
Subject
GRB 161219B: MITSuME Akeno Optical Observation
Date
2016-12-21T05:31:31Z (9 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
T.Fujiwara, Y.Saito, Y. Tachibana, T. Yoshii,
Y.Ono, S.Harita, Y.Muraki, K.Morita, T.Ozawa, K.Saisho,Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 161219B (A. D'Ai et al., GCN
Circular #20296) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2016-12-20 11:49:20 UT (~17.0 hour after the burst) and
we detected the optical counterpart in g', Rc and Ic band.
The measured magnitudes were listed as follows.
We obtained following results for the magnitudes.
T0+[hour] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
~17.8 12:34:26 4920 18.83 +/- 0.11 18.23 +/- 0.09 18.14 +/- 0.11
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 20313
Subject
GRB 161219B: VLA Detection
Date
2016-12-21T02:13:57Z (9 years ago)
From
Kate Alexander at Harvard <kalexander@cfa.harvard.edu>
K. D. Alexander (Harvard), T. Laskar (NRAO / UC Berkeley), and E. Berger
(Harvard) report on behalf of a larger collaboration:
We observed the Swift GRB 161219B (D���Ai et al. GCN 20296) at multiple
frequencies with the Karl G. Jansky Very Large Array (VLA) beginning 2016
December 20.26 UT (11.4 hours after the burst). At a mean frequency of
14.75 GHz, we detect a radio source with a preliminary flux density of ~0.9
mJy at
RA (J2000) = 06:06:51.428 +/- 0.001
Dec (J2000) = -26:47:29.52 +/- 0.01
consistent with the position of the optical afterglow and the refined
Swift/XRT position (Beardmore et al. GCN 20297). Follow-up observations are
planned.
We thank the VLA staff for rapidly executing these observations.
GCN Circular 20309
Subject
GRB 161219B: ISON/Terskol optical observations
Date
2016-12-20T21:25:52Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Mokhnatkin (KIAM), A. Pozanenko (IKI), A.
Volnova (IKI), I. Molotov (KIAM) report on behalf of larger GRB
follow-up collaboration:
We observed the field of GRB 161219B (Swift trigger 727541; D'Ai,
GCN 20296) with K-800 (0.8m) telescope of ISON/Terskol observatory
starting on December, 19 (UT) 18:57:51, i.e. about 9 minutes after GRB
onset. We obtained several unfiltered images of 30 s exposure. The
optical afterglow (D'Ai et al., GCN 20296; Kruehler et al., GCN 20299;
Guidorzi et al., GCN 20300; Martin-Carrillo et al., GCN 20305) is
clearly visible in separate images. Preliminary light curve of the
afterglow can be found in
http://grb.rssi.ru/GRB161219B/GRB161219B_161219_K800.png
Photometry is based on nearby USNO-B1.0 stars
USNO-B.1_id R2
0631-0120570 13.78
0632-0119151 14.86
0632-0119187 14.03
0632-0119198 15.05
0632-0119218 14.66
0631-0120752 14.81
GCN Circular 20308
Subject
GRB 161219B: Swift-BAT refined analysis
Date
2016-12-20T18:22:59Z (9 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
A. D'Ai (INAF-IASFPA), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 161219B (trigger #727541)
(D'Ai, et al., GCN Circ. 20296). The BAT ground-calculated position is
RA, Dec = 91.717, -26.801 deg which is
RA(J2000) = 06h 06m 52.0s
Dec(J2000) = -26d 48' 02.1���
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.
The mask-weighted light curve shows a soft, weak peak at around T-10 sec,then the
main peak starts at T-2 sec, peaks at T+2 sec and decays to background by T+8 sec.
T90 (15-350 keV) is 6.94 +- 0.79 sec (estimated error including systematics).
The time-averaged spectrum from T-0.54 to T+8.38 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.29 +- 0.35,
and Epeak of 61.9 +- 16.8 keV (chi squared 44.89 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.5 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+1.56 sec in the 15-150 keV band is
5.3 +- 0.4 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.84 +- 0.08 (chi squared 53.05 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/727541/BA/
GCN Circular 20306
Subject
GRB 161219B: Swift/UVOT Detection
Date
2016-12-20T17:08:41Z (9 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and A. D'Ai (INAF-IASFPA)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 161219B
112 s after the BAT trigger (D'Ai et al., GCN Circ. 20296).
A source consistent with the XRT position
(Beardmore et al. GCN Circ. 20297)
is detected in the initial UVOT exposures.
The source is detected in the first white exposure at the position:
RA(J2000) = 06:06:51.43 = 91.71428
DEC(J2000) = -26:47:29.5 = -26.79152
with an uncertainty of 0.42" (90% confidence)
Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are
in the table below. Fading is seen in all filters.
The detection in the w2 filter is consistent
with a relatively low redshift as suggested by
Kruehler et al. (GCN Circ. 20299).
Filter T_start(s) T_stop(s) Exp(s) Mag
white 112 261 147 16.1 +/- 0.1
v 653 673 19 16.7 +/- 0.2
b 579 599 20 16.9 +/- 0.1
u 324 573 246 16.0 +/- 0.1
u 44962 45868 875 18.0 +/- 0.1
w1 702 722 20 15.6 +/- 0.1
m2 677 697 19 15.7 +/- 0.2
w2 629 649 20 15.9 +/- 0.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst.
GCN Circular 20305
Subject
GRB 161219B: Watcher optical observations
Date
2016-12-20T14:15:30Z (9 years ago)
From
Antonio Martin-Carrillo at UCD,Space Science Group <antonio.martin-carrillo@ucd.ie>
A. Martin-Carrillo (UCD), D. Murphy (UCD), L. Hanlon (UCD), H. J. van Heerden (UFS), B. van Soelen (UFS) and P. J. Meintjes (UFS)
We observed the field of GRB 161219B (D'Ai et al, GCN 20296) using the 40cm UCD Watcher telescope at Boyden Observatory in South Africa.
Due to bad weather, observations were delayed until December 20th at 00:30 UT (T0+5.67h) and were taken under poor seeing. Based on combined images in SDSS r��� filter, at a mid-time of 00:45 UT we derive a preliminary magnitude of r'=18.06 (AB system). This value is in agreement with the magnitude reported by Kruehler et al (GCN 20299) at 01:42 UT, one hour after our reported mid-time. In fact, our data shows no indication of fading between 00:30 UT to 02:00 UT when our observations stopped, indicating an optical plateau.
Magnitudes were calibrated using several nearby APASS stars. No correction for Galactic extinction in the direction of the GRB has been applied.
GCN Circular 20300
Subject
GRB 161219B: LCO Sutherland observations
Date
2016-12-20T08:31:43Z (9 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc
(U. Nova Gorica), C.G. Mundell (U. Bath) on behalf of a large
collaboration report:
We observed Swift GRB 161219B (D'Ai et al. GCN 20296) on December 19,
from 20:43 to 20:56 UT (1.9-2.1 hours since the GRB) with 1-m LCO
telescope units in Sutherland with SDSS r and i filters. Within the
enhanced enhanced XRT error circle (Beardmore et al. GCN 20297) we
clearly detect the optical counterpart reported by UVOT (D'Ai et al.)
with the following values:
Mid Time Exposure Filter Magnitude
(hours) (s)
-------------------------------------------------------
1.93 120 SDSS-R 17.38 +- 0.02
1.93 120 SDSS-I 16.72 +- 0.02
-------------------------------------------------------
as calibrated against nearby USNOB-1 source RA(J2000)=06:06:52.743,
DEC(J2000)=-26:46:29.49 using nominal R2=15.12 mag, I=14.37 mag.
We however point out that the source is positionally coincident with a
USNOB-1 source: 06:06:51.366, -26:47:29.80, which has nominal R2=20.14
mag. This likely corresponds to the extended galaxy mentioned by
Kruehler et al (GCN 20299) in Pan-STARRS data.
GCN Circular 20299
Subject
GRB 161219B: GROND afterglow observations
Date
2016-12-20T07:57:56Z (9 years ago)
From
Thomas Kruehler at MPE Garching <kruehler@mpe.mpg.de>
T. Kruehler, P. Wiseman and J. Greiner (all MPE Garching) report on
behalf of the GROND team:
We observed the field of GRB 161219B (Swift trigger 727541; D'Ai,
GCN #20296) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO
La Silla Observatory (Chile).
Observations started at 01:33 UT on 2016-12-20, 6.7 hr after the GRB
trigger. They were performed at an average seeing of 1".1, and at an
average airmass of 1.3.
Based on combined images with 14.5 min of total exposures in g'r'i'z'
and 12.0 min in JHK at a mid-time of 01:42 UT on 2016-12-20,
we derive the following preliminary magnitudes (all in AB system)
for the optical/NIR afterglow (D'Ai et al., GCN 20296).
g' = 18.04 +- 0.05 mag
r' = 18.08 +- 0.05 mag
i' = 17.98 +- 0.05 mag
z' = 17.88 +- 0.05 mag
J = 17.68 +- 0.05 mag
H = 17.57 +- 0.07 mag
K = 17.54 +- 0.08 mag
Given magnitudes are calibrated against Pan-STARRS/2MASS field stars
and are not corrected for the expected Galactic foreground extinction
corresponding to a reddening of E_(B-V) = 0.028 mag in the direction of
the burst (Schlafly & Finkbeiner 2011).
We note the presence of a bright (r=21 mag) and visibly extended galaxy
in the Pan-STARRS data at the position of GRB 161219B. This is likely
the host galaxy of the GRB and would, if confirmed, indicate a
relatively low redshift.
GCN Circular 20298
Subject
GRB 161219B: Swift-XRT refined Analysis
Date
2016-12-20T04:36:01Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia
(ASDC), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU) and A. D'Ai report on behalf of the Swift-XRT team:
We have analysed 7.7 ks of XRT data for GRB 161219B (D'Ai et al. GCN
Circ. 20296), from 92 s to 22.7 ks after the BAT trigger. The data
comprise 238 s in Windowed Timing (WT) mode (the first 9 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. 20297).
The late-time light curve (from T0+4.7 ks) can be modelled with a
power-law decay with a decay index of alpha=0.75 (+/-0.07).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.05 (+/-0.08). The
best-fitting absorption column is 1.21 (+0.21, -0.20) x 10^21 cm^-2,
in excess of the Galactic value of 3.1 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.82 (+/-0.07) and a
best-fitting absorption column of 1.64 (+0.23, -0.22) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.9 x 10^-11 (4.8 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.64 (+0.23, -0.22) x 10^21 cm^-2
Galactic foreground: 3.1 x 10^20 cm^-2
Excess significance: 9.8 sigma
Photon index: 1.82 (+/-0.07)
If the light curve continues to decay with a power-law decay index of
0.75, the count rate at T+24 hours will be 0.22 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.3 x
10^-12 (1.0 x 10^-11) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00727541.
This circular is an official product of the Swift-XRT team.
GCN Circular 20297
Subject
GRB 161219B: Enhanced Swift-XRT position
Date
2016-12-20T01:22:43Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2622 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 161219B, 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 = 91.71401, -26.79163 which is equivalent
to:
RA (J2000): 06h 06m 51.36s
Dec (J2000): -26d 47' 29.9"
with an uncertainty of 1.7 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 20296
Subject
GRB 161219B: Swift detection of a burst with an optical afterglow
Date
2016-12-19T19:07:03Z (9 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
A. D'Ai (INAF-IASFPA), J. A. Kennea (PSU),
H. A. Krimm (CRESST/NSF/USRA), N. P. M. Kuin (UCL-MSSL),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and
M. H. Siegel (PSU) report on behalf of the Swift Team:
At 18:48:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 161219B (trigger=727541). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 91.717, -26.790 which is
RA(J2000) = 06h 06m 52s
Dec(J2000) = -26d 47' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single triangle-
shaped structure with a duration of about 10 sec. The peak count rate
was ~3900 counts/sec (15-350 keV), at ~2 sec after the trigger.
The XRT began observing the field at 18:50:27.5 UT, 108.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 91.7140, -26.7915 which
is equivalent to:
RA(J2000) = 06h 06m 51.35s
Dec(J2000) = -26d 47' 29.4"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 11 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 http://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 (3.06 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4
(+2.38/-1.96) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 111 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 06:06:51.41 = 91.71421
DEC(J2000) = -26:47:29.2 = -26.79144
with a 90%-confidence error radius of about 0.5 arc sec. This position is 0.9
arc sec. from the center of the XRT error circle. The estimated magnitude is
16.10 with a 1-sigma error of about 0.03. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.03.
Burst Advocate for this burst is A. D'Ai (antonino.dai AT ifc.inaf.it).
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/too.html.)
[GCN OPS NOTE(20dec16): Per author's request, the "-29:47:29.2"
in the 4th paragraph was changed to "-26:47:29.2".]