GRB 201223A
GCN Circular 29201
Subject
GRB 201223A: SVOM-GWAC detected the optical counterpart during prompt emission phase
Date
2020-12-30T00:50:53Z (5 years ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
L. P. Xin(NAOC), X. H. Han(NAOC), J. Y. Wei(NAOC), L. H. Li(NAOC),
J. Wang(GXU), D. Turpin(CEA), H. B. Cai(NAOC), X. Y. Wang(NJU),
C. Wu(NAOC), X. G. Wang(GXU), Z. G. Dai (NJU), G. W. Li(NAOC),
E. W. Liang (GXU), S.S.Sun(GXU), L. Huang(NAOC), X. M. Lu(NAOC),
Y. G. Yang(HNU), C. Gao(GXU), Y. L. Qiu(NAOC), and J. S. Deng(NAOC) report:
The optical counterpart of GRB 201223A (Gropp et al., GCN #29158,
Wood et al., GCN #29161) reported by (Lipunov et al., GCN #29157;
Gropp et al., GCN #29158; Zhu et al., GCN #29159; Hu et al., GCN #29160;
Hosokawa et al., GCN #29164; Filipp Dmitrievich Romanov GCN #29165;
Xin et al., GCN #29166; Belkin et al., GCN #29167; Kumar et al., GCN #29168;
Xu et al., GCN #29169; Gupta te al., GCN #29173; Pankov et al., GCN #29174;
Kumar et al., GCN #29176; Belles et al., GCN #29177 )
was detected by Ground Wide Angle Camera (GWAC) in white band
at Xinglong observatory, China, during the Swift prompt emission phase.
The exposure time for each GWAC image is 10 seconds.
Preliminary process showed that the brightness was about R~15.5 mag at ~2 sec after the burst,
and then brighten to the peak of R~14.8 mag at about 80 sec post the trigger time.
All these magnitudes were calibrated to USNO B1.0 R2 mag catalog.
More analyses are still continuing.
GCN Circular 29180
Subject
GRB 201223A: AROMA-N Optical Observation
Date
2020-12-27T22:15:11Z (5 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
M. Nakamura, K. Hasuda, T. Sakamoto (AGU)
We observed the field of GRB 201223A detected by Swift
(Gropp et al., GCN Circ. 29158) with the 14-inch AGU Robotic
Optical Monitor for Astrophysical object - Narrow (AROMA-N)
located at the Sagamihara campus of Aoyama Gakuin University.
58 images of 60 sec exposures were taken in the R filter
starting from December 23 18:04:02 (UT) about 5.6 minutes
after the trigger and stopped on December 23 19:16:09 (UT).
We do not detect the optical afterglow both in the individual
images and the stacked image. The estimated five sigma
upper limit of the combined image (total exposure of 3480 sec)
is ~17.3 mag using the USNO-B1 catalog.
GCN Circular 29177
Subject
GRB 201223A: Swift/UVOT Detection
Date
2020-12-26T22:03:09Z (5 years ago)
From
Alexander Belles at PSU/Swift <aub1461@psu.edu>
���A. Belles (PSU) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 201223A
79 s after the BAT trigger (Gropp et al., GCN Circ. 29158).
A source consistent with the XRT position (Goad et al., GCN Circ. 29170)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 08:51:09.51 = 132.78961 (deg.)
Dec (J2000) = +71:10:47.4 = 71.17984 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 79 229 147 16.06+/-0.03
white 571 1019 186 18.04+/-0.08
white 5921 6121 196 >20.17
white 12121 12630 497 20.09+/-0.30
v 621 1069 58 >17.44
b 547 1167 58 17.97+/-0.25
b 11208 12115 885 >20.38
u_FC 292 541 246 16.75 +/- 0.04
u 694 1142 38 >17.58
w1 670 1118 58 >17.65
m2 645 1093 58 >17.87
w2 596 1045 58 >17.81
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 29176
Subject
GRB 201223A: HCT optical upper limit
Date
2020-12-26T05:51:35Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar(IITB), D. K. Sahu (IIA), V. Bhalerao(IITB), G. C. Anupama(IIA), S.
Barway(IIA) report on behalf of the HCT team:
We observed GRB 201223A detected by Swift-BAT (J.D. Gropp et al., GCN
#29158); optical counterpart first reported by V. Lipunov et al., (GCN
#29157) with 2.0m Himalayan Chandra Telescope (HCT). We obtained a series
of 180-sec exposures in the Bessell R filter and did not detect the
afterglow in our stacked image. We obtained the following upper limit:
-------------------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Exposure | Filter | Lim_mag (5-sigma) |
-------------------------------------------------------------------
2459208.4569 | 28.99 | 180*10 (stacked) | Bessell R | > 22.49 |
-------------------------------------------------------------------
Our upper limit is consistent with power-law decay extrapolation suggested
by D. Xu et al., (GCN #29169), Kumar et al., (GCN #29168).
These observations were carried out under the ToO program "HCT-2020-C3-P6".
We thank HCT staff for undertaking the observations.
GCN Circular 29174
Subject
GRB 201223A: AbAO optical observations
Date
2020-12-24T21:31:45Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE, IKI), A. Pozanenko (IKI), S. Belkin (IKI), R. Ya.
Inasaridze (AbAO), V. R. Ayvazian (AbAO), G. V. Kapanadze (AbAO), A.
Volnova (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 201223A (Gropp et al., GCN 29158; Wood et
al., GCN 29161) with AS-32 telescope of Abastumani observatory (AbAO) in
R-filter. The optical afterglow (Lipunov et al., GCN 29157; Gropp
et al., GCN 29158; Zhu et al., GCN 29159; Hu et al., GCN 29160;
Hosokawa et al., GCN 29164; Romanov et al., GCN 29165; Xin et al., GCN
29166; Belkin et al., GCN 29167; Kumar et al., GCN 29168; Xu et al., GCN
29169; Gupta et al., GCN 29173) is detected in stacked images.
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2020-12-23 19:39:59 0.0733 R 8*60 19.38 0.17 19.8
2020-12-23 21:19:22 0.1517 R 35*60 20.28 0.13 20.9
The photometry is based on nearby USNO-B1.0 stars.
GCN Circular 29173
Subject
GRB 201223A: 1.3m DFOT and 1.04m ST optical observations
Date
2020-12-24T17:09:51Z (5 years ago)
From
Rahul Gupta at ARIES, India <rahulbhu.c157@gmail.com>
Rahul Gupta (ARIES), Dimple (ARIES), Amit Kumar (ARIES), Vineet Ojha
(ARIES), Ankur Ghosh (ARIES), Amar Aryan (ARIES), Shashi B. Pandey
(ARIES), and Kuntal Misra (ARIES) report:
We observed the optical afterglow ( Lipunov et al., GCN 29157; Gropp
et al., GCN 29158; Zhu et al., GCN 29159; Hu et al., GCN 29160;
Hosokawa et al., GCN 29164; Romanov et al., GCN 29165; Xin et al., GCN
29166; Belkin et al., GCN 29167; and Kumar et al., GCN 29168) of Swift
and Fermi detected GRB 201223A (Gropp et al., GCN 29158; and Wood et
al., GCN 29161) using the 1.3m Devasthal Fast Optical Telescope (DFOT)
and 1.04m Sampurnanand Telescope (ST) of Aryabhatta Research Institute
of Observational Sciences (ARIES), India. The observations were
started on 2020-12-23 at 19:01:46 UT. Multiple frames having an
exposure time of 300 s were taken in the I filter using DFOT and in
BVRI filters using ST. We clearly detected the optical counterpart at
the position reported by Gropp et al., GCN 29158.
The preliminary photometric estimate of the afterglow using I band
data of DFOT is the following :
Date Start_UT T_start-T0 (hrs) Filter Exp time (s)
Magnitude Mag_err
------------------------------ ------------------------------
------------------------------ ------------------------------
2020-12-23 19:07:55 1.158 I 300*1
18.71 0.04
------------------------------ ------------------------------
------------------------------ ------------------------------
The magnitude is not corrected for the Galactic and Host extinction in
the direction of the burst. Photometric calibration is performed using
the standard stars from the USNO-B1.0 catalogue. Further processing
of data is going on.
This circular may be cited.
GCN Circular 29171
Subject
GRB 201223A: Swift-XRT refined Analysis
Date
2020-12-24T15:18:33Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), A. D'Ai
(INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B.
Sbarufatti (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester) and J.D. Gropp report on
behalf of the Swift-XRT team:
We have analysed 8.0 ks of XRT data for GRB 201223A (Gropp et al. GCN
Circ. 29158), from 81 s to 18.2 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. The enhanced XRT position for
this burst was given by Goad et al. (GCN Circ. 29170).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.82 (+/-0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.87 (+0.18, -0.13). The
best-fitting absorption column is 4.1 (+4.0, -0.9) x 10^20 cm^-2,
consistent with the Galactic value of 3.1 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum is 3.5 x 10^-11 (2.8 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.1 (+4.0, -0.9) x 10^20 cm^-2
Galactic foreground: 3.1 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.87 (+0.18, -0.13)
If the light curve continues to decay with a power-law decay index of
0.82, the count rate at T+24 hours will be 5.7 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.0 x
10^-13 (1.6 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01014316.
This circular is an official product of the Swift-XRT team.
GCN Circular 29170
Subject
GRB 201223A: Enhanced Swift-XRT position
Date
2020-12-24T14:52:52Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1078 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 201223A, 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 = 132.79017, +71.17923 which is equivalent
to:
RA (J2000): 08h 51m 9.64s
Dec (J2000): +71d 10' 45.2"
with an uncertainty of 1.8 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 29169
Subject
GRB 201223A: NOT optical upper limit and NEXT powerlaw decay
Date
2020-12-24T14:29:07Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
D. Xu (NAOC), D. B. Malesani (DTU Space), P. Galindo (NOT), Z.P. Zhu
(NAOC, HUST), D. A. Kann (HETH/IAA-CSIC), report on behalf of a larger
collaboration:
We observed the field of GRB 201223A (Gropp et al., GCN 29158) using the
2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera.
We obtained 2x120s Sloan r-band frames starting at 02:21:52 UT on
2020-12-24, i.e., 8.4 hr after the BAT trigger.
The previously reported optical afterglow (Lipunov et al. GCN 29157;
Gropp et al., GCN 29158; Zhu et al. GCN 29159; Hu et al. GCN 29160;
Hosokawa et al. GCN 29164; Romanov et al. GCN 29165; Xin et al. GCN
29166; Belkin et al., GCN 29167; Kumar et al., GCN 29168) is not
detected in the stacked image, down to a limiting magnitude of r > 22.0 mag.
Further analysis of our previous NEXT observations (Zhu et al. GCN
29159) shows that the afterglow is decaying as F_rband ~ t^(-\alpha),
where \alpha = 1.1 since the very beginning. The afterglow would be
slightly fainter than 22.0 mag if this powerlaw decay is extrapolated
until the NOT observational time, being consistent with the observed NOT
upper limit. So the afterglow could be decaying in a single powerlaw
until the NOT observation or have broken to a steeper decay before the
NOT observation.
GCN Circular 29168
Subject
GRB 201223A: GROWTH-India Telescope (GIT) photometric follow-up.
Date
2020-12-24T14:21:13Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), U. Stanzin (IAO), V. Bhalerao (IITB), G. C. Anupama (IIA),
S. Barway (IIA), report on behalf of the GROWTH-India collaboration:
We observed GRB 201223A detected by Swift-BAT (J.D. Gropp et al., GCN
#29158); optical counterpart first reported by V. Lipunov et al., (GCN
#29157) with 0.7m GROWTH-India Telescope, starting at
2020-12-23T18:30:33.51 UT. We obtained multiple images of 300 sec each in
the r' filter. We clearly detected the afterglow at a position consistent
with Swift-UVOT (GCN #29158) and MASTER-Net OT (GCN #29157) positions.
We obtained the following photometric results:
------------------------------------------------------------------
JD (start) | T_start-T0 (hrs) | Filter | Mag (AB)|
------------------------------------------------------------------
2459207.27122 | 0.5 | r' | 18.52 +/- 0.03
2459207.28623 | 0.9 | r' | 19.12 +/- 0.04
2459207.32568 | 1.8 | r' | 19.98 +/- 0.09
2459207.34029 | 2.2 | r' | 20.15 +/- 0.09
------------------------------------------------------------------
Combining our photometric results with r band measurements of Z.P. Zhu et.
al., (GCN #29159), we conclude that the source is fading with a power-law
index of 1.04 +/- 0.01. The magnitudes are calibrated against PanSTARRs PS1
data release, (Flewelling et al., 2018) and not corrected for galactic
extinction. Processing of more data is underway.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree
field of view, set up by the Indian Institute of Astrophysics and the
Indian Institute of Technology Bombay with support from the Indo-US Science
and Technology Forum (IUSSTF) and the Science and Engineering Research
Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the
Indian Astronomical Observatory (Hanle), operated by the Indian Institute
of Astrophysics (IIA).
GCN Circular 29167
Subject
GRB 201223A: Mondy and Kitab optical observations
Date
2020-12-24T13:09:08Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), N. Pankov (HSE), E. Klunko
(ISTP), A. Novichonok (Petrozavodsk State University, KIAM), Sh.
Ehgamberdiev (UBAI) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 201223A (Gropp et al., GCN 29158) with
AZT-33IK telescope of Sayan observatory (Mondy) starting on Dec. 23 (UT)
18:29:01 and Kitab-ISON RC-36 telescope starting (UT) 19:25:57. The
optical transient (Lipunov et al. GCN 29157; Gropp et al., GCN 29158;
Zhu et al. GCN 29159; Hu et al. GCN 29160; Hosokawa et al. GCN 29164;
Romanov et al. GCN 29165; Xin et al. GCN 29166) is detected in our
stacked images in R-filter.
Preliminary photometry of the optical transient in a combined images is
following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2020-12-23 18:29:01 0.05943 R 10*120 18.95 0.23 19.5 AZT-33IK
2020-12-23 18:29:01 0.05943 R 55*120 19.38 0.09 22.1 AZT-33IK
2020-12-23 19:25:57 0.08161 R 60*60 19.40 0.20 19.6 RC-36
The photometry is based on the nearby USNO-B1.0 stars
USNO-B1.0_id R2
1611-0080890 18.64
1612-0081305 18.44
GCN Circular 29166
Subject
GRB 201223A: GWAC-F60A optical afterglow observations
Date
2020-12-24T06:56:16Z (5 years ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
L. P. Xin(NAOC), L. H. Li(NAOC), X. H. Han(NAOC), J. Y. Wei(NAOC), J. Wang(GXU),
C. Wu(NAOC), X. G. Wang(GXU), E. W. Liang (GXU), Y. L. Qiu(NAOC), and J. S. Deng(NAOC) report:
We began to observe GRB 201223A (Gropp et al., GCN #29158,
Wood et al., GCN #29161) with Xinglong GWAC-F60A telescope, China,
at 17:59:10.1 (UT), 23th. Dec. 2020, about 44 sec after the burst.
A series of R, I, and B band images were obtained.
The optical afterglow reported by (Lipunov et al., GCN #29157; Gropp et
al., GCN #29158; Zhu et al., GCN #29159; Hu et al.���GCN #29160;
Hosokawa et al., GCN #29164; Filipp Dmitrievich Romanov GCN #29165)
was clear detected in our images.
The brightness is fading from 15.0 mag to 18.8 mag in R band
during about 100 sec to 10000 sec after the burst.
The R-band brightness is calibrated to the USNO B1.0 catalog,
(RA=08:50:21.447, DEC=+71:12:12.80, J2000, R2=9.92)
More analysis are still continuing.
The message may be cited.
GCN Circular 29165
Subject
GRB 201223A: iTelescope optical afterglow observations
Date
2020-12-24T02:49:44Z (5 years ago)
From
Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997@gmail.com>
I observed the field of GRB 201223A (Gropp et al., GCN Circ. 29158)
with remote telescope T18 (0.32-m f/8.0 reflector + CCD) of
iTelescope.Net in observatory AstroCamp at Nerpio (Spain) on
2020-12-23 since 19:49:22 UT (1 hour 50 minutes 56 seconds after the
trigger). 5 images (with exposures 300, 120 and 180 seconds) were
obtained with Astrodon luminance filter and 4 images (exposures: 300
and 60 seconds) with photometric Johnson V filter. I detected the
optical afterglow in images with position: RA 08:51:09.46 Dec
+71:10:47.00. It is not present in the Pan-STARRS images.
The following magnitudes were measured from comparison to r magnitudes
of nearby stars from Pan-STARRS DR1 catalogue (Chambers et al., 2016):
Time of start (UT) Exp.time (s.) Bin. Mag. r Mag. error Filter
---------------------------------------------------------------------------
19:49:22 300 1 19.2 0.2 Luminance
19:56:25 300 1 19.3 0.4 V
20:26:25 300 2 19.9 0.4 V
20:33:07 300 2 20.1 0.3 Luminance
---------------------------------------------------------------------------
Magnitudes were not corrected for Galactic extinction.
Stacked image (4x300 + 2x120 + 180 sec.) available here:
https://www.flickr.com/photos/filipp-romanov/50753199496
GCN Circular 29164
Subject
GRB 201223A: MITSuME Akeno optical observation
Date
2020-12-24T02:08:01Z (5 years ago)
From
Ryohei Hosokawa at Tokyo Institute of Technology <hosokawa@hp.phys.titech.ac.jp>
R. Hosokawa, K. L. Murata, R. Adachi, M. Niwano, F. Ogawa, N.
Nakamura, N. Ito, S. Ogata, H. Takamatsu, H. Hara, Y. Yatsu, and N.
Kawai (TokyoTech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 201223A (J.D. Gropp et al., GCN #29158,
J. Wood et al., GCN #29161) 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 at 2020-12-23 17:59:18 UT (52s after Swift BAT
trigger). We detected the point source at the position consistent with
the afterglow detected previously (Lipunov et al. GCN #29157, Gropp et
al., GCN #29158, Z.P. Zhu
et al. GCN #29159, Y.-D. Hu et al. GCN #29160).
We measured the magnitudes as follows.
T0+[sec] MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
52 17:59:48 60 g'=15.45+/-0.05, Rc=15.04+/-0.03, Ic=14.77+/-0.04
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used PS1 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The images were processed in real-time through the MITSuME GPU
reduction pipeline (Niwano et al.,
https://doi.org/10.1093/pasj/psaa091,
https://arxiv.org/abs/2008.11486; https://github.com/MNiwano/Eclaire).
GCN Circular 29163
Subject
GRB 201223A: Swift-BAT refined analysis
Date
2020-12-24T01:56:53Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),
J.D. Gropp (PSU), H. A. Krimm (NSF),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
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+882 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 201223A (trigger #1014316)
(Gropp et al., GCN Circ. 29158). The BAT ground-calculated position is
RA, Dec = 132.735, 71.176 deg which is
RA(J2000) = 08h 50m 56.3s
Dec(J2000) = +71d 10' 34.9"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 53%.
The mask-weighted light curve shows a multi-peaked structure that
starts at ~T-25 s and ends at ~T+8 s. The main peak occurs at ~T0.
T90 (15-350 keV) is 29.0 +- 6.7 sec (estimated error including
systematics).
The time-averaged spectrum from T-25.18 to T+7.82 sec is best fit
by a simple power-law model. The power law index of the time-averaged
spectrum is 1.35 +- 0.13. The fluence in the 15-150 keV band is
1.3 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T-0.18 sec in the 15-150 keV band is 1.5 +- 0.2 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/1014316/BA/
GCN Circular 29161
Subject
GRB 201223A: Fermi GBM Detection
Date
2020-12-23T23:53:30Z (5 years ago)
From
Joshua Wood at MSFC/Fermi-GBM <joshua.r.wood@nasa.gov>
J. Wood (NASA/MSFC) reports on behalf of the Fermi GBM Team:
"At 17:58:25.69 UT on 23 December 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 201223A (trigger 630439110 / 201223749)
which was also detected by the Swift/BAT and Swift/XRT
(Gropp et al. 2020, GCN 29158). The GBM
on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 63 degrees.
The GBM light curve shows multiple peaks
with a duration (T90) of about 33 s (50-300 keV).
The time-averaged spectrum from T0-17 s to T0+13 s is
best fit by a Band function with Epeak = 86 +/- 12 keV,
alpha = 0.14 +/- 0.38 and beta = -2.6 +/- 0.4.
A power law function with an exponential
high-energy cutoff fits the spectrum equally well.
The power law index is -0.14 +/- 0.24 and
the cutoff energy, parameterized as Epeak, is 99 +/- 8 keV.
The event fluence (10-1000 keV) in this time interval is
(2.1 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.1 s in the 10-1000 keV band
is 2.4 +/- 0.2 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 Circular 29160
Subject
GRB 201223A: BOOTES-4/MET early optical observation
Date
2020-12-23T19:05:41Z (5 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, E. Fernandez-Garcia, M. A. Castro, A. J. Castro-Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga), S. Guziy (Univ. of Nikolaev) and D. Xiong, Y. Fan, X. Zhao, J. Bai, C. Wang, Y. Xin (Yunnan Nacional Astronomical Observatory) on behalf of a larger collaboration, report:
Following the detection of GRB 201223A by Swift (Gropp et al. GCNC 29158), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical
Observatory (China) started to gather images in clear filter starting at 18:01:22 UT (~176 s after trigger). The optical afterglow reported by Swift/UVOT (Gropp et al. GCNC 29158), MASTER (Lipunov et al. GCNC 29157) and Nanshan/NEXT (Zhu et al. GCNC 29159) is detected with a magnitude of 15.7+-0.15. Additional observations are ongoing.
We thank the staff at Lijiang observatory for their excellent support.
GCN Circular 29159
Subject
GRB 201223A: Nanshan/NEXT early optical afterglow detection
Date
2020-12-23T18:58:50Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu (NAOC, HUST), S.Y. Fu, M. Zhang, X. Liu, D. Xu (NAOC), X. Gao (Urumqi
No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 201223A (Gropp et al., GCN 29158) using the
NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China.
Observations automatically started at 18:01:14 UT on 2020-12-23, i.e.,
168 s after the BAT trigger. We obtained a series of 2x40s, 4x60s and
12x90s frames in the Sloan r-filter, and observations are ongoing.
An uncatalogued decaying optical transient is detected at the Swift/UVOT
position (Gropp et al., GCN 29158), which is thus concluded to be the
optical afterglow of burst. The afterglow has r = 15.67 +/- 0.01 mag in
our first image, calibrated with nearby PS1 stars.
[GCN OPS NOTE(24Dec2020) Per author's request, M. Zhang was added
to the author list.]
GCN Circular 29158
Subject
GRB 201223A: Swift detection of a burst with a bright optical counterpart
Date
2020-12-23T18:12:13Z (5 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
J.D. Gropp (PSU), S. D. Barthelmy (GSFC), J. A. Kennea (PSU),
N. J. Klingler (PSU), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU) and
M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 17:58:26 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 201223A (trigger=1014316). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 132.849, +71.174 which is
RA(J2000) = 08h 51m 24s
Dec(J2000) = +71d 10' 26"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 50 sec. The peak count rate
was ~1600 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 17:59:40.7 UT, 73.7 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 132.78615, 71.17926 which
is equivalent to:
RA(J2000) = 08h 51m 08.68s
Dec(J2000) = +71d 10' 45.3"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 75 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 consistent with the Galactic value of 3.13
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 78 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 08:51:09.51 = 132.78963
DEC(J2000) = +71:10:47.4 = 71.17982
with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.8
arc sec. from the center of the XRT error circle. The estimated magnitude is
16.16 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.05.
Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu).
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/)