GRB 210104A
GCN Circular 29232
Subject
GRB 210104A: Fermi GBM Final Real-time Localization
Date
2021-01-04T11:37:17Z (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 11:26:59 UT on 4 Jan 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210104A (trigger 631452424.865632 / 210104477).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 107.9, Dec = 67.1 (J2000 degrees, equivalent to J2000 07h 11m, 67d 05'), with a statistical uncertainty of 2.9 degrees.
The angle from the Fermi LAT boresight is 135.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210104477/quicklook/glg_skymap_all_bn210104477.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210104477/quicklook/glg_healpix_all_bn210104477.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210104477/quicklook/glg_lc_medres34_bn210104477.gif
GCN Circular 29233
Subject
GRB 210104A: Swift detection of a burst with a bright optical counterpart
Date
2021-01-04T11:41:25Z (4 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
E. Troja (NASA/GSFC/UMCP), M. G. Bernardini (INAF-OAB),
A. A. Breeveld (UCL-MSSL), P. D'Avanzo (INAF-OAB),
P. A. Evans (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU),
A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB),
K. L. Page (U Leicester) and T. Sbarrato (INAF-OAB) report on behalf
of the Neil Gehrels Swift Observatory Team:
At 11:26:59 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 210104A (trigger=1015873). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 103.705, +64.661 which is
RA(J2000) = 06h 54m 49s
Dec(J2000) = +64d 39' 39"
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 40 sec. The peak count rate
was ~16000 counts/sec (15-350 keV), at ~21 sec after the trigger.
The XRT began observing the field at 11:28:01.8 UT, 62.7 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 103.7707, 64.6743 which is equivalent to:
RA(J2000) = 06h 55m 4.97s
Dec(J2000) = +64d 40' 27.5"
with an uncertainty of 5.3 arcseconds (radius, 90% containment). This
location is 111 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy.
The initial flux in the 2.5 s image was 1.41e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of nominal 150.0 seconds with the White
filter starting 70 seconds after the BAT trigger. There is a candidate
afterglow in the list of sources generated on-board at
RA(J2000) = 06:55:05.25 = 103.77188
DEC(J2000) = +64:40:34.0 = 64.67611
with a 90%-confidence error radius of about 1.10 arc sec. This position is 6.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.52. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.04.
Burst Advocate for this burst is E. Troja (eleonora.troja AT nasa.gov).
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 29234
Subject
GRB 210104A: BALROG localization (Fermi Trigger 631452424 / GRB 210104477)
Date
2021-01-04T12:00:07Z (4 years ago)
From
Jochen Greiner at MPE,Garching <jcg@mpe.mpg.de>
B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
631452424 at 11:26:59 on 04 Jan. 2021 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 102.7+/-5.4 deg
Decl.(2000.0) = 69.8+/-1.3 deg
We estimate an additional systematic error of 1 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB210104477/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB210104477/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB210104477/json
GCN Circular 29235
Subject
GRB 210104A: GWAC-F60A optical afterglow observations
Date
2021-01-04T12:00:26Z (4 years ago)
From
Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>
L. P. Xin(NAOC), J. Wang(GXU), X. H. Han(NAOC), J. Y. Wei(NAOC),
G. W. LI(NAOC), L. H. Li(NAOC), C. Wu(NAOC), X. G. Wang(GXU),
E. W. Liang (GXU), R. S. Zhang(NAOC), Y. L. Qiu(NAOC),
and J. S. Deng(NAOC) report:
We began to observe GRB 210104A (Troja et al., GCN 29233)
with Xinglong GWAC-F60A telescope, China,
at 11:28:00 (UT), 4th. Jan. 2021, about 61 sec after the burst.
A series of R, I, and B band images were obtained.
The optical afterglow (Troja et al., GCN 29233)
was clear detected in our images.
The brightness is about 14.5 mag in R band at 71 sec after the burst,
calibrated to the USNO B1.0 catalog.
The observations are continuing
GCN Circular 29236
Subject
GRB 210104A: BOOTES-4/MET early optical afterglow detection
Date
2021-01-04T12:05:43Z (4 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, M.D. Caballero-Garcia, M. A. Castro Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga), S. Guziy (Univ. of Nikolaev) and D. R. Xiong, Y.F. Fan, J.M. Bai, C. J. Wang, Y.X. Xin, X. H. Zhao (Yunnan Observatories of CAS) on behalf of a larger collaboration, report:
"Following the detection of GRB 210104A by Swift (Troja et al. GCNC 29233) and Fermi (Fermi GBM team GCNC 29232, Biltzinger et al. GCNC 29234), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical Observatory (China) started to gather images in clear filter starting at 2021-01-04 11:27:52 UT (~53 s after trigger). The optical afterglow reported by Swift/UVOT (Troja et al. GCNC 29233) is detected with a magnitude of 15.15+-0.15 in the first 5 s exposure image. Additional observations are ongoing."
We thank the staff at Lijiang observatory for their excellent support.
GCN Circular 29237
Subject
GRB 210104A: MITSuME Akeno optical observation
Date
2021-01-04T12:44:41Z (4 years ago)
From
Ryohei Hosokawa at Tokyo Institute of Technology <hosokawa@hp.phys.titech.ac.jp>
R. Hosokawa, R. Adachi, M. Niwano, K. L. Murata, 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 210104A (The Fermi GBM team
, GCN 29232, E. Troja et al., GCN 29233, B. Biltzinger et al., GCN 29234) 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 2021-01-04 11:27:54 UT (55s after Swift BAT
trigger). We detected the point source at the position consistent with
the afterglow detected previously(E. Troja et al., GCN 29233, L. P.
Xin et al., GCN 29235, Y.-D. Hu et al., GCN 29236).
We measured the magnitudes as follows.
T0+[sec] MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
55 11:28:24 60 g'=14.6+/-0.1, Rc=14.2+/-0.1, Ic=13.8+/-0.1
------------------------------------------------------------------------------------------------
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 29238
Subject
GRB 210104A: Assy optical observations
Date
2021-01-04T14:22:05Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Kim (FAI, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (FAI),
S. Belkin (IKI) report on behalf of GRB-IKI-FuN:
We observed the GRB 210104A (Fermi GBM team, GCN 29232; Troja et al.,
GCN 29233) with AZT-20 telescope of Assy-Turgen observatory starting on
Jan. 04 (UT) 12:55:33 in r'-filter. We detect the optical afterglow
(Troja et al., GCN 29233; Xin et al., GCN 29235; Hu et al., GCN 29236;
Hosokawa et al., GCN 29237).
Preliminary photometry of the afterglow obtained in a few initial
imaging is following
Date UT start t-T0 Filter Exp. OT Err. UL (3sigma)
(mid, days) (s)
2021-04-01 12:55:33 0.0632 r'(AB) 5*60 17.97 0.06 22.7
The photometry is based on nearby stars of PanSTARRS-PS1.
Observations is continuing.
GCN Circular 29239
Subject
Fermi GRB 210104A: Global MASTER-Net observations report
Date
2021-01-04T15:30:28Z (4 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 210104A ( Fermi GBM team, GCN 29232) errorbox 13896 sec after notice time and 13949 sec after trigger time at 2021-01-04 15:19:29 UT, with upper limit up to 18.0 mag. Observations started at twilight. The observations began at zenith distance = 51 deg. The sun altitude is -10.7 deg.
The galactic latitude b = 27 deg., longitude l = 149 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1518462
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
13980 | 2021-01-04 15:19:29 | MASTER-Tavrida | (06h 52m 09.73s , +68d 11m 37.6s) | C | 60 | 17.7 |
13980 | 2021-01-04 15:19:29 | MASTER-Tavrida | (07h 08m 11.29s , +68d 09m 51.0s) | C | 60 | 17.9 |
14060 | 2021-01-04 15:20:49 | MASTER-Tavrida | (06h 59m 02.10s , +66d 11m 00.3s) | C | 60 | 17.7 |
14060 | 2021-01-04 15:20:49 | MASTER-Tavrida | (07h 13m 46.16s , +66d 09m 08.7s) | C | 60 | 18.0 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 29241
Subject
GRB 210104A: MITSuME Ishigaki optical observation
Date
2021-01-04T20:02:05Z (4 years ago)
From
Takashi Horiuchi at Ishigakijima Astronomical Obs <takashi.horiuchi@nao.ac.jp>
Takashi Horiuchi, Hidekazu Hanayama (NAOJ), Katsuhiro L. Murata,
Yoichi Yatsu, Nobuyuki Kawai (Tokyo Tech) report on behalf of the
MITSuME collaboration:
We observed the field of GRB 210104A (The Fermi GBM team,
GCN 29232, E. Troja et al., GCN 29233) with the optical three
color (g', Rc, and Ic) CCD cameras attached to the 105 cm
Murikabushi telescope of Ishigakijima Astronomical Observatory,
Okinawa, Japan.
The observation with a series of 60 sec exposures started on
2021-01-04 13:58:34 UT (150 min after Swift BAT trigger).
We detected the point source at the position consistent with
the afterglow reported by Swift UVOT and obtained the
magnitudes as follows.
T0+[min] MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
150 2021-01-04T14:14:02 1500 g'=19.17+/-0.08, Rc=18.12+/-0.04, Ic=17.96+/-0.09
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
The SDSS catalog (DR16) is used for flux calibration.
GCN Circular 29245
Subject
GRB 210104A: Enhanced Swift-XRT position
Date
2021-01-04T21:54:22Z (4 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 2419 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 210104A, 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 = 103.77281, +64.67604 which is equivalent
to:
RA (J2000): 06h 55m 5.47s
Dec (J2000): +64d 40' 33.8"
with an uncertainty of 1.4 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 29246
Subject
GRB 210104A: Fermi GBM detection
Date
2021-01-04T22:13:38Z (4 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
C. Malacaria (NASA-MSFC/USRA), C. Fletcher (USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 11:26:59.87 UT on 04 January 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 210104A (trigger 631452424 / 210104477).
which was also detected by the Swift/BAT (Troja et al. 2021, GCN 29233)
The Fermi GBM Final Real-time Localization (GCN 29232) is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 134 degrees.
The GBM light curve roughly consists of three separated peaks
with a duration (T90) of about 32 s (50-300 keV).
The time-averaged spectrum of each peak is best fit by
a power law function with an exponential high-energy cutoff.
For the first peak, from T0-3.1 s to T0+9.2 s,
the power law index is -1.2 +/- 0.1 and
the cutoff energy, parameterized as Epeak, is 155 +/- 21 keV.
For the second peak, from T0+16.4 s to T0+22.5 s,
the power law index is -0.92 +/- 0.1 and Epeak is 245 +/- 23 keV.
For the third peak, from T0+24.6 s to T0+33.8 s,
the power law index is -1.1 +/- 0.1 and Epeak is 199 +/- 14 keV.
The event fluence values (10-1000 keV) in the first, second and third time interval are
(4.004 +/- 0.270)E-06, (5.350 +/- 0.246)E-06 and
(8.266 +/- 0.276)E-06 erg/cm^2, respectively.
The 1-sec peak photon flux measured
starting from T0+19.7 s in the 10-1000 keV band
is 17.2 +/- 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 29247
Subject
GRB 210104A: Swift/UVOT Detection
Date
2021-01-04T22:21:25Z (4 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210104A 71 s after the BAT trigger
(Troja et al., GCN Circ. 29233).
A fading source is detected in all UVOT filters in the initial exposures, at the position given in
Troja et al., (GCN Circ. 29233), and also seen by others (Xin et al., GCN Circ. 29235; Hosokawa et
al., GCN Circ. 29237; Kim et al., GCN Circ. 29238; Lipunov et al., GCN Circ. 29239 and Horiuchi et
al., GCN Circ. 29241).
Preliminary detections 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 71 221 147 14.61 �� 0.02
white 562 582 20 16.23 �� 0.05
white 1512 1706 39 17.02 �� 0.05
b 538 558 20 16.59 �� 0.10
u_FC 283 533 246 15.28 �� 0.03
v 613 632 20 16.36 �� 0.16
uvw1 662 682 20 16.12 �� 0.16
uvm2 637 657 20 16.58 �� 0.25
uvw2 588 608 20 17.09 �� 0.26
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 29248
Subject
GRB 210104A: MASTER OT rebrightening detection
Date
2021-01-04T22:48:33Z (4 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, N.Tiurina,P.Balanutsa,F.Balakin,
V.Vladimirov, A.Kuznetsov,K.Zhirkov,D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik,
A.Chasovnikov,A.Pozdnyakov,V.Topolev, D.Cheryasov(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov, Yu. Sergienko (Blagoveschensk Educational StateUniversity)
MASTER-Tavrida robotic telescope
(Global MASTER-Net http://observ.pereplet.ru, Lipunov et al. 2010, Advances in Astronomy,v.2010,30L)
started (Lipunov et al. GCN 29239)
inspect of Fermi and Swift GRB 210104A (Fermi GCN 29232, 29246;Ttrig=11:26:59;
Swift GCN Troja et al. GCN 29233,Beardmore et al. GCN 29245, Breeveld et al. GCN 29247 ;
Barthelmy https://gcn.gsfc.nasa.gov/other/210104A.gcn3 )
at sunset at Lomonosov MSU Crimean observatory at 2021-01-04 15:19:29 UT.
We detect rebrightening of OT (discovered by Swift GCN 29233 and observed by Xin et al., GCN Circ. 29235; Hosokawa etal. GCN 29237; Kim et al. GCN 29238;
Lipunov et al. GCN 29239, Horiuchi et al. GCN 29241, Breeveld et al. GCN 29247)
MASTER OT J065505.45+644035.0 at 2021-01-04 15:48:32UT with unfiltered
m_OT=17.3.
The message may be cited.
GCN Circular 29251
Subject
GRB 210104A: Swift-BAT refined analysis
Date
2021-01-05T02:33:46Z (4 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU),
E. Troja (NASA/GSFC/UMCP), 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 210104A (trigger #1015873)
(Troja et al., GCN Circ. 29233). The BAT ground-calculated position is
RA, Dec = 103.771, 64.675 deg which is
RA(J2000) = 06h 55m 04.9s
Dec(J2000) = +64d 40' 30.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.
The mask-weighted light curve shows a multi-peaked structure that
starts at ~T-1 s and ends at ~T+45 s. Several prominent peaks occur
at ~T+4 s, ~T+21 s, ~T+27 s, and ~T+34 s, respectively. T90 (15-350 keV)
is 32.06 +- 0.49 sec (estimated error including systematics).
The time-averaged spectrum from T-1.00 to T+45.39 sec is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 1.55 +- 0.04. The fluence in the 15-150 keV band is
8.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from
T+26.78 sec in the 15-150 keV band is 12.1 +- 0.4 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/1015873/BA/
GCN Circular 29252
Subject
GRB 210104A: Nanshan/NEXT optical powerlaw decay
Date
2021-01-05T03:04:27Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi
No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210104A (Troja et al., GCN 29233) using the
NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China.
Observations started at 11:59:19 UT (i.e., 0.538 hr post-burst) on
2021-01-04 and ended at 22:34:07 UT (i.e., 11.11 hr post-burst) on
2021-01-04, and a series of 120 s, 200 s, 300 s Sloan r-band frames were
obtained.
Preliminary analysis of the data shows that afterglow is decaying as
F_rband ~ t^(-\alpha), where \alpha = 0.73 since the very beginning of
our observations.
If the afterglow continues to decay in this way, it would be of r ~ 20.3
mag at 1 day post-burst, and still bright enough for optical spectroscopy.
GCN Circular 29254
Subject
GRB 210104A: DOAO optical afterglow observations
Date
2021-01-05T03:31:37Z (4 years ago)
From
Gregory SungHak Paek at SNU <shpaek@astro.snu.ac.kr>
Gregory S.H. Paek (SNU ARC/SNU), Myungshin Im (SNU ARC/SNU), Taewoo Kim,
and Wonseok Kang (DOAO) on behalf of a larger collaboration
We observed the optical counterpart of GRB 210104A (E. Troja et al.,
GCN #29233)
with the 1-m class telescope in Deokheung Optical Astronomy Observatory
(DOAO). We calibrated flux with the SDSS catalog and used an AB magnitude
system.
----------------------------------------------------------
Filter Date-obs[UT] Exp.time[s] Mag Mag Error
----------------------------------------------------------
R 2021-01-04T13:37:29.100 300*4 18.34 0.07
I 2021-01-04T13:42:37.050 300*4 18.04 0.05
----------------------------------------------------------
The magnitudes are not corrected for galactic extinction.
GCN Circular 29257
Subject
GRB 210104A: 1.3m DFOT Optical Afterglow Detection
Date
2021-01-05T11:38:59Z (4 years ago)
From
Amit Kumar at ARIES, India <amitkundu515@gmail.com>
Amit Kumar (ARIES), Rahul Gupta (ARIES), Dimple (ARIES), Ankur Ghosh
(ARIES), Nikita Rawat (ARIES), Brajesh Kumar (ARIES), Vibhore Negi (ARIES),
Amar Aryan (ARIES), Shashi B. Pandey (ARIES), and Kuntal Misra (ARIES)
report:
We observed the optical afterglow of the Fermi (Fermi GBM team GCNC 29232,
Biltzinger et al. GCNC 29234) and Swift detected GRB 210104A (Troja et al.
GCNC 29233) with the 1.3m Devsthal Fast Optical Telescope (DFOT) at
Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital
(India), from 2021-01-04 17:50:11 to 2021-01-04 18:35:28 UTC (from ~6.386
to 7.141 hours after the burst). We observed 10 frames each of 240 seconds
in the Bessell R filter. We clearly detected the optical afterglow of GRB
210104A in all individual frames within the Swift XRT enhanced error circle
(Beardmore et al. 29245) as reported by Xin et al. GCN 29235 and later by
Hu et al. GCN 29236, Hosokawa et al. GCN 29237, Kim et al. GCN 29238,
Takashi et al. GCN 29241, Lipunov et al. GCN 29248, Zhu et al. GCN 29252
and Gregory et al. GCN 29254.
The estimated preliminary magnitude for the first R-band image is as
follows:
T_start-T0 (hours) Start Date (UTC) Filter Magnitude (mag)
-----------------------------------------------------------
-----------------------------------------------------------
6.386 2021-01-04T17:50:11 R 18.95 +- 0.07
Photometry is done based on the USNO-B1.0 catalog. The quoted magnitude is
not corrected for the Galactic extinction in the direction of GRB 210104A.
This message may be cited.
GCN Circular 29258
Subject
Konus-Wind detection of GRB 210104A
Date
2021-01-05T14:17:49Z (4 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, A.Lysenko, A. Ridnaia,
D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 210104A (Swift detection: Troja et al., GCN 29233;
Fermi GBM detection: Malacaria et al., GCN 29246)
triggered Konus-Wind (KW) at T0=41224.536 s UT (11:27:04.536).
The burst light curve shows multiple partly overlapped peaks
in the interval from ~T0-2 s to ~T0+33 s.
The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB210104_T41224/
As observed by Konus-Wind, the burst had
a fluence of (2.15 �� 0.35)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0+26.624,
of (1.13 �� 0.19)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+33.024 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 = -1.00 (-0.16,+0.18),
the high energy photon index beta = -2.52 (-0.52,+0.24),
the peak energy Ep = 157 (-18,+23) keV,
chi2 = 90/97 dof.
The spectrum near the peak count rate (measured from T0+16.640
to T0+33.024 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 = -0.95 (-0.11,+0.11),
the high energy photon index beta = -2.47 (-1.10,+0.24),
the peak energy Ep = 176 (-24,+37) keV,
chi2 = 83/97 dof.
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.
GCN Circular 29260
Subject
GRB 210104A: Swift-XRT refined Analysis
Date
2021-01-05T14:26:50Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), P. D'Avanzo (INAF-OAB), M.G.
Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , A. Tohuvavohu (U.
Toronto), B. Sbarufatti (PSU) and E. Troja report on behalf of the
Swift-XRT team:
We have analysed 5.9 ks of XRT data for GRB 210104A (Troja et al. GCN
Circ. 29233), from 69 s to 76.7 ks after the BAT trigger. The data
comprise 1.8 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 29245).
The late-time light curve (from T0+6.1 ks) can be modelled with a
power-law decay with a decay index of alpha=1.35 (+0.08, -0.07).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.012 (+/-0.028). The
best-fitting absorption column is 1.10 (+/-0.08) x 10^21 cm^-2, in
excess of the Galactic value of 5.1 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.92 (+0.11, -0.10)
and a best-fitting absorption column of 1.24 (+0.31, -0.29) x 10^21
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.5 x 10^-11 (3.9 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.24 (+0.31, -0.29) x 10^21 cm^-2
Galactic foreground: 5.1 x 10^20 cm^-2
Excess significance: 4.1 sigma
Photon index: 1.92 (+0.11, -0.10)
If the light curve continues to decay with a power-law decay index of
1.35, the count rate at T+24 hours will be 0.047 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x
10^-12 (1.8 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01015873.
This circular is an official product of the Swift-XRT team.
GCN Circular 29262
Subject
GRB 210104A: early ATLAS detections of the bright afterglow
Date
2021-01-05T17:47:51Z (4 years ago)
From
Stephen Smartt at Queen's U/Belfast <s.smartt@qub.ac.uk>
S. J. Smartt, K. W. Smith (QUB), S. Srivastav,, D. R. Young,
M. Fulton, (QUB) L. Denneau, A. Heinze, J. Tonry, H. Weiland (IfA,
Univ. Hawaii), A. Rest (STScI), B. Stalder (LSST), C. Stubbs
(Harvard), O. McBrien, J. Gillanders, L. Shingles (QUB),
T.-W. Chen (MPE)
We report serendipitous observations of GRB210104A (Troja et al. GCN
29233) by ATLAS, the twin telescope system on Haleakala and Mauna
Loa that surveys the whole northern sky every 2 days (see Tonry et
al. 2018, PASP, 130f4505). Optical transients are automatically
detected on the difference images and discoveries (Smith et al. 2020,
PASP, 132h5002) are made public through the IAU Transient Name Server.
During the course of its survey, ATLAS happened to be observing the
field of GRB210104A starting 1min 47sec after the Swift BAT trigger at
2021-01-04 11:26:59 UT (Troja et al. GCN 29233). This was a fortunate
coincidence in normal survey mode and not a triggered pointing.
We detect the bright UVOT afterglow as initially reported in (Troja et
al. GCN 29233), and appear to have the caught it early and bright at
o = 13.9 along with rapid fading (see also Xin et al, GCN29235, Hu et
al. 29236, Hosokawa et al. GCN 29237, Kim et al. GCN 29238, Lipunov et
al. 29239),
It was detected at a position :
RA = 06:55:05.37 (103.77240) DEC = +64:40:34.2 (+64.67618)
The expoures were 30sec long in the o-band (an r+i composite),
with start time and magnitudes as follows :
###MJD UTC m dm
59218.478319 2021-01-04 11:28:46.762 UTC 13.94 0.01
59218.481544 2021-01-04 11:33:25.402 UTC 15.56 0.01
59218.487080 2021-01-04 11:41:23.712 UTC 16.43 0.02
59218.497226 2021-01-04 11:56:00.326 UTC 16.96 0.03
59218.670448 2021-01-04 16:05:26.707 UTC >18.4 (3 sigma limit)
GCN Circular 29265
Subject
GRB 210104A: Assy continued optical observations
Date
2021-01-05T22:12:02Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Kim (FAI, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (FAI),
S. Belkin (IKI), Y. Aimuratov (FAI) report on behalf of GRB IKI FuN:
We continued observations of the GRB 210104A (Fermi GBM team, GCN 29232;
Troja et al., GCN 29233; Frederiks et al., GCN 29258) with AZT-20
telescope of Assy-Turgen observatory starting on Jan. 05 (UT) 12:55:33
in r'-filter. We detect the optical afterglow (Troja et al., GCN
29233; Xin et al., GCN 29235; Hu et al., GCN 29236; Hosokawa et al., GCN
29237; Kim et al., GCN 29238; Lipunov et al., GCN 29239; Horiuchi et
al., GCN 29241; Breeveld et al., GCN 29247; Zhu et al., GCN 29252; Paek
et al., GCN 29254; Kumar et al., GCN 29257; Smartt et al., GCN 29262).
Preliminary photometry obtained in images in the beginning of
observations on Jan. 05 is following
Date UT start Filter Exp. OT Err.
(s)
2021-01-04 15:35:27 r'(AB) 20*60 20.85 0.07
2021-01-04 16:20:20 r'(AB) 20*60 21.23 0.10
2021-01-04 17:05:11 r'(AB) 20*60 21.19 0.06
The photometry is based on nearby stars of PanSTARRS-PS1.
Observations are continuing.
GCN Circular 29268
Subject
GRB 210104A: CALET Gamma-Ray Burst Monitor detection
Date
2021-01-06T10:15:24Z (4 years ago)
From
Valentin Pal'shin at AGU <val@phys.aoyama.ac.jp>
M. L. Cherry (LSU),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long bright GRB 210104A (Swift detection: Troja et al.,
GCN Circ. 29233, Palmer et al., GCN Circ. 29251;
Fermi GBM detection: Malacaria et al., GCN Circ. 29246;
Konus-Wind detection: Frederiks et al., GCN Circ. 29258;
https://gcn.gsfc.nasa.gov/other/210104A.gcn3) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 11:26:56.318 UTC on 4 January 2021
(http://cgbm.calet.jp/cgbm_trigger/flight/1293794541/).
The burst signal was seen by all CGBM detectors.
The burst light curve shows multiple partially overlapped pulses which
start at T+2.5 sec and end at T+36.5 sec. The T90 and T50 durations
measured by the SGM data are 31.2 +- 2.0 sec and 11.6 +- 9.4 sec
(40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1293794541/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.
GCN Circular 29269
Subject
GRB 210104A: iTelescope optical upper limit
Date
2021-01-06T10:19:18Z (4 years ago)
From
Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997@gmail.com>
I observed the field of GRB 210104A (Troja et al., GCN Circ. 29233)
with remote telescope T11 (0.50-m f/6.8 reflector + CCD + f/4.5 focal
reducer) of iTelescope.Net in New Mexico Observatory. Three images
with AstroDon Luminance filter and with 300 seconds exposure time were
obtained on 2021-01-05. Start time of exposures: 06:46:48 UT (~19.3 h.
after trigger; Binx1), 06:52:21 UT (Binx2) and 06:57:44 UT (Binx1). I
did not detect any optical transients (magnitude limit of about 21.0
in stacked image).
GCN Circular 29273
Subject
GRB 210104A: SARA-KP 0.9m Optical Afterglow Detection
Date
2021-01-06T22:01:36Z (4 years ago)
From
Samalka Anandagoda at Clemson University <iananda@g.clemson.edu>
S. Anandagoda, S. Geier, K. Pellegrin and D. Hartmann report:
We observed the field of GRB 20210104A (Fermi GBM Team, GCN 29232; Troja et al., GCN 29233; Biltzinger et al., GCN 29234) using the SARA 0.9m optical telescope located at Kitt Peak, AZ, USA, equipped with the Alta-E6-1105 camera. Observation started at 06:20:04 UTC on 2021-01-05 and ended at 09:34:43 UTC (~ 18 to 21 hours after the detection of the burst by the Fermi GBM Team). We obtained a series of 120s exposure frames in the Bessell R filter. We clearly detect the optical afterglow of GRB 20210104A at the enhanced Swift-XRT position (Beardmore et al., GCN 29245).
The estimated magnitude of the GRB afterglow was 20.61 found by stacking 20 images of 120s each in the Bessell R band filter.
T_start-T0 (hrs) T_end-T0 (hrs) Start Date (UTC) Filter Magnitude (mag)
���������������������������������������������������������������������������������������-------------------------
----------------------------------------------------------------------------------------------------------------
18:53 19:33 2021-01-05T06:20:04 R 20.61
Photometry is done based on the USNO-B1.0 catalog.
The Southeastern Association for Research in Astronomy (SARA) consortium operates three telescopes: the 0.9-m SARA-KP at Kitt Peak in Arizona, and the 0.6-m SARA-CT at Cerro Tololo in Chile, and the 1.0-m SARA-RM (formerly the JKT) telescope at Roque de los Muchachos Observatory in the Canary Islands. For more information see: Keel et al. (2016): https://iopscience.iop.org/article/10.1088/1538-3873/129/971/015002
GCN Circular 29274
Subject
GRB210104A: VIRT optical transient detection.
Date
2021-01-07T05:51:35Z (4 years ago)
From
Priyadarshini Gokuldass at U. of the Virgin Islands <priyadass.94@gmail.com>
We observed the field of GRB210104A (The Fermi GBM team, GCN 29232, Troja
et al., GCN 29233) with the 0.5m Virgin Island Robotic Telescope (VIRT) at
the University of the Virgin Islands' Etelman Observatory on 01-05-2021
starting at 23:44:00 UT with a midpoint of observation of T+40 hrs. We
performed a series of exposures in R filter with a total exposure of ~10ks.
The weather conditions were clear during the hours of observation with an
average airmass of 1.7.
We detect a source consistent with the UVOT position (Troja et al., GCN
29233) and optical transient identified by others (e.g., Bilitzinger et
al., GCN 29234, Xin et al., GCN 29235, Hu et al., GCN 29236) with magnitude:
R= 20.8 +/- 0.3
This magnitude is consistent with the powerlaw decay rate of alpha = 0.73
reported by Zhu et al, GCN 29252.
The magnitude is estimated from comparison to nearby USNO B1 stars and is
not corrected for Galactic extinction. Further analysis is in progress. 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.
GCN Circular 29275
Subject
GRB 210104A: GMG observations
Date
2021-01-07T08:57:00Z (4 years ago)
From
Jirong Mao at Yunnan Obs <jirongmao_obs@ynao.ac.cn>
J. Mao, X. Ding, X.-L. Zhang, and J.-M. Bai (YNAO) report:
We observed the field of GRB 210104A (Troja et al. GCN 29233) with
the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan
Observatories. The observation began at UT 13:00:11, 4, Jan. 2021, about
1.5 hours after the trigger. We clearly detected the source, and the preliminary
magnitude was measured to be R~17.6. Further analysis of the observations during
the night is ongoing.
GCN Circular 29277
Subject
GRB 210104A: SAO RAS optical observations
Date
2021-01-07T15:00:45Z (4 years ago)
From
Moskvitin Alexander at SAO RAS <mosk@sao.ru>
A. S. Moskvitin, V. V. Vlasyuk (SAO RAS)
on behalf of GRB follow-up team report.
We observed the field of the GRB 210104A (Fermi GBM Team, GCN #29232;
Troja et al., GCN #29233; Biltzinger et al., GCN #29234)
with the 0.5m Astrosib RC500-2 telescope of SAO RAS
equipped with the Rc filter and FLI Proline PL16801 camera.
The observations carried out on 2021 Jan. 4, 0.32--0.38 days
after the trigger (T_mid - T0 = 0.35d).
In the 37 x 20 sec. stacked image we clearly detect the GRB OT
(Troja et al., GCN #29233; Xin et al., GCN #29235; Hu et al.,
GCN #29236; Hosokawa et al., GCN #29237; Kim et al., GCN #29238;
Lipunov et al., GCN #29239; Horiuchi et al., GCN #29241;
Breeveld et al., GCN #29247; Zhu et al., GCN #29252; Paek et al.,
GCN #29254; Kumar et al., GCN #29257; Smartt et al., GCN #29262;
V. Kim, GCN #29265; S. Anandagoda, GCN #29273; P. Gokuldass,
GCN #29274; J. Mao, GCN #29275)
with the brightness of R = 19.4 +/- 0.1. The preliminary photometry
is based on R2 magnitudes of nearby USNO-B1 stars.
GCN Circular 29283
Subject
GRB 210104A: Assy continued optical observations, correction to GCN circ. 29265
Date
2021-01-10T16:05:11Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Kim (FAI, Pulkovo Observatory), S. Belkin (IKI), A. Pozanenko (IKI),
M. Krugov (FAI), Y. Aimuratov (FAI) report on behalf of GRB IKI FuN:
We continued observations of the GRB 210104A (Fermi GBM team, GCN 29232;
Troja et al., GCN 29233; Frederiks et al., GCN 29258; Cherry et al.,
GCN 29268) with AZT-20 telescope of Assy-Turgen observatory starting on
Jan. 05 (UT) 12:55:33 in r'-filter. We detect the optical afterglow
(Troja et al., GCN 29233; Xin et al., GCN 29235; Hu et al., GCN 29236;
Hosokawa et al., GCN 29237; Kim et al., GCN 29238, 29265; Lipunov et
al., GCN 29239; Horiuchi et al., GCN 29241; Breeveld et al., GCN 29247;
Zhu et al., GCN 29252; Paek et al., GCN 29254; Kumar et al., GCN 29257;
Smartt et al., GCN 29262; Romanov, GCN 29269; Anandagoda et al., GCN
29273; Gokuldass, GCN 29274; Mao et al., GCN 29275; Moskvitin et al.,
GCN 29277).
Preliminary photometry is following
Date UT start Filter Exp. OT(AB) Err. UL(3 sigma)
(s)
2021-01-06 15:18:17 r' 82*60 22.00 0.08 23.0
2021-01-09 17:22:22 r' 136*60 22.88 0.19 24.1
The photometry is based on nearby stars of PanSTARRS-PS1.
Observations are continuing.
We also report corrected date of observation reported in the GCN 29265.
The correct table of the GCN 29265 should be as follows
Date UT start Filter Exp. OT(AB) Err.
2021-01-05 15:35:27 r' 20*60 20.85 0.07
2021-01-05 16:20:20 r' 20*60 21.23 0.10
2021-01-05 17:05:11 r' 20*60 21.19 0.06
GCN Circular 29286
Subject
GRB 210104A: Mondy optical observations, light curve
Date
2021-01-10T22:34:47Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), V. Kim (FAI,
Pulkovo Observatory), Y. Aimuratov (FAI), M. Krugov (FAI) report on
behalf of GRB IKI FuN:
We observed GRB 210104A (Fermi GBM team, GCN 29232; Troja et al., GCN
29233; Frederiks et al., GCN 29258; Cherry et al., GCN 29268) with
AZT-33IK telescope of Sayan observatory (Mondy). We detect the optical
afterglow (Troja et al., GCN 29233; Xin et al., GCN 29235; Hu et al.,
GCN 29236; Hosokawa et al., GCN 29237; Kim et al., GCN 29238, 29265;
Lipunov et al., GCN 29239; Horiuchi et al., GCN 29241; Breeveld et al.,
GCN 29247; Zhu et al., GCN 29252; Paek et al., GCN 29254; Kumar et al.,
GCN 29257; Smartt et al., GCN 29262; Romanov, GCN 29269; Anandagoda et
al., GCN 29273; Gokuldass, GCN 29274; Mao et al., GCN 29275; Moskvitin
et al., GCN 29277).
Preliminary photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma)
(mid, days) (s)
2021-01-07 15:10:23 3.19681 R 80*90 n/d n/d 22.1
2021-01-08 15:22:18 4.20438 R 59*120 22.2 0.2 22.9
2021-01-09 11:51:54 5.07980 R 90*120 22.7 0.3 22.7
The photometry is based on nearby stars of USNO-B1.0
USNO-B1.0_id R2
1546-0139059 15.53
1546-0139029 14.82
A light curve of the afterglow based on our observations including
reported early (Kim et al., GCN 29238, 29265, 29283) can be found in
http://grb.rssi.ru/GRB210104A/GRB210104A_LC.png
GCN Circular 29291
Subject
GRB 210104A: AROMA-N Optical Afterglow Detection
Date
2021-01-12T06:36:42Z (4 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 210104A (Troja et al., GCN Circ. 29233;
Malacaria et al., GCN Circ. 29246; Frederiks et al., GCN Circ. 29258;
Cherry et al., GCN Circ. 29268) with the 14-inch AGU Robotic Optical
Monitor for Astrophysical object - Narrow (AROMA-N) located at
the Sagamihara campus of Aoyama Gakuin University.
60 images of 60 sec exposures were taken in the R filter starting
from January 4 11:29:50 (UT) about 171 seconds after the trigger and
stopped on January 4 12:45:20 (UT). We detected the optical afterglow
at the consistent position previously reported (Troja et al., GCN Circ. 29233;
Xin et al., GCN Circ. 29235; Hu et al., GCN Circ. 29236; Hosokawa et al.,
GCN Circ. 29237; Kim et al., GCN Circ. 29238, 29265; Lipunov et al.,
GCN Circ. 29239; Horiuchi et al., GCN Circ. 29241; Breeveld et al.,
GCN Circ. 29247; Zhu et al., GCN Circ. 29252; Paek et al., GCN Circ. 29254;
Kumar et al., GCN Circ. 29257; Smartt et al., GCN Circ. 29262; Romanov,
GCN Circ. 29269; Anandagoda et al., GCN Circ. 29273; Gokuldass, GCN Circ. 29274;
Mao et al., GCN Circ. 29275; Moskvitin et al., GCN Circ. 29277;
Belkin et al., GCN Circ. 29286). The clear decay signature was visible in our
images. The magnitudes of the initial 60 s image and the combined
image from T+2915 sec to T+3577 sec images (total exposure of 540 sec)
were 14.3 mag and 17.1 mag. The afterglow light curve of our data showed
the initial temporal decay of -1.4 following by the shallow decay of -0.6
at the break around T+650 sec. Our reported magnitudes are calibrated using
the USNO-B1 catalog.
GCN Circular 29299
Subject
GRB 210104A: AstroSat CZTI detection
Date
2021-01-13T18:24:27Z (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 210104A, which was
also detected by Fermi-GBM (GCN #29232), Swift-BAT (GCN #29233), Konus-Wind
(GCN #29258) and CALET-CGBM (GCN #29268).
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
2021-01-04 11:27:17.5 UT. The measured peak count rate associated with the
burst is 867 (+60, -56) cts/s above the background in the combined data of
four quadrants, with a total of 7003 (+407, -394) cts. The local mean
background count rate was 555 (+2, -2) cts/s. Using cumulative rates, we
measure a T90 of 33 (+7, -1) 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 2021-01-04 11:27:17 UT. The measured
peak count rate is 606 (+86, -55) cts/s above the background in the
combined Veto data of four quadrants, with a total of 4520 (+693, -789)
cts. The local mean background count rate was 2009 (+4, -5) cts/s. We
measure a T90 of 35 (+7, -14) 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 29304
Subject
GRB 210104A: JCMT SCUBA-2 sub-mm observations
Date
2021-01-15T21:55:33Z (4 years ago)
From
Ian Smith at Rice U <ian.smith.astronomy@gmail.com>
I.A. Smith (Rice U.), D.A. Perley (LJMU), and N.R. Tanvir
(U. of Leicester) report:
We observed the Swift UVOT location of GRB 210104A (Troja
et al., GCN Circ. 29233) using the SCUBA-2 sub-millimeter
continuum camera on the James Clerk Maxwell Telescope. The
observation started at 08:23 UT on 2021-01-05, with the
mid-point of the run at 0.894 days after the burst trigger.
Exposures totaling 1.0 hours were made in very good weather
conditions. No source was detected, with the RMS background
noise being 1.7 mJy/beam at 850 microns and 14.5 mJy/beam
at 450 microns.
We thank Kevin Silva, Mark Rawlings, and the JCMT staff for
the prompt support of these observations that were taken under
project M20BP026.
GCN Circular 29318
Subject
GRB 210104A: Late-time CAHA 2.2m detection
Date
2021-01-18T15:51:26Z (4 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. Rossi (INAF-OAS), A. de Ugarte Postigo
(HETH/IAA-CSIC, DARK/NBI), C. C. Thoene (HETH), M. Blazek, J. F. Agui
Fernandez (both HETH/IAA-CSIC), and J. I. Vico Linares (CAHA) report:
We observed the afterglow position (Troja et al., GCN #29233) of the
bright Swift/Fermi GRB 210104A (Swift detection: Troja et al., GCN
#29233; GBM detection: Fermi GBM Team, GCN #29232; Biltzinger et al.,
GCN #29234; Konus-Wind detection: Frederiks et al., GCN #29258; CALET
detection: Cherry et al., GCN #29268; AstroSat CZTI detection: Nadella
et al., GCN #29299) with CAFOS at the 2.2m telescope at Calar Alto,
Almeria, Spain, in the Rc band. We obtained 6 x 600 s exposures,
centered at 11.4624 days after the GRB, under good conditions but
mediocre seeing.
After removing the halo of a nearby star, the afterglow (Xin et al., GCN
#29235; Hu et al., GCN #29236; Hosokawa et al., GCN #29237; Kim et al.,
GCNs #29238,29265,29283; Horiuchi et al., GCN #29241; Breeveld et al.,
GCN #29247; Lipunov et al., GCN #29248; Zhu et al., GCN #29252; Paek et
al., GCN #29254; Kumar et al., GCN #29257; Smartt et al., GCN #29262;
Anandagoda et al., GCN #29273; Gokuldass et al., GCN #29274; Mao et al.,
GCN #29275; Moskvitin et al., GCN #29277; Belkin et al., GCN #29286;
Nakamura et al., GCN #292291) is faintly but clearly detected.
Against three SDSS comparison stars (transformed to Rc band using the
Lupton 2005 equations, then transformed back to AB magnitude), we
measure Rc = 23.67 +/- 0.14 mag. This value is in agreement with the
extrapolation of the light curve decay reported by Belkin et al., GCN
#29286 (A. Pozanenko, priv. comm.). This implies there is no significant
evidence for a supernova rise, and therefore the redshift of GRB 210104A
is conservatively estimated to be z > 0.4 (e.g., SN 2012eb associated
with GRB 120714B at z ~ 0.4 peaks at r' ~ 22.2 mag 12 days after
trigger, Klose et al. 2019, A&A, 622, A138).
We thank Alexei Pozanenko for discussions.
GCN Circular 29337
Subject
GRB 210104A: 3.6m DOT optical upper limit
Date
2021-01-20T11:44:16Z (4 years ago)
From
Dimple Panchal at ARIES, India <dimplepanchal96@gmail.com>
Dimple (ARIES), K. Misra (ARIES), A. Ghosh (ARIES), R. Gupta (ARIES), A.
Kumar (ARIES), S.B. Pandey (ARIES) report:
We observed the field of GRB 210104A (Troja et al. GCN #29233) with Aries
Devasthal Faint Object Spectrograph and Camera (ADFOSC) mounted on the 3.6m
Devasthal Optical Telescope (DOT). The observations started on 2021-01-13
at 19:52:50 UT (9.374 days after the burst). We obtained a set of
consecutive images with short exposure times to avoid saturation from the
nearby bright star. We do not detect any optical counterpart upto a
magnitude limit of 23.2 in the stacked image.
GCN Circular 29440
Subject
GRB 210104A: LBT observations
Date
2021-02-09T15:09:31Z (4 years ago)
From
Andrea Melandri at INAF-OAB <andrea.melandri@inaf.it>
A. Melandri (INAF-OAB), and A Rossi (INAF-OAS) report on behalf of the CIBO collaboration:
We observed the field of GRB 210104A (Troja et al., GCN 29233; Malacaria et al., GCN 29246) simultaneously in the r' and z' bands with the LBC imager mounted on LBT (Mt Graham, AZ, USA). We obtained 20min of imaging on 2021-02-05, 31.8 days after the burst trigger. Observations were performed under poor seeing (~1.7") conditions but reached a depth of r~25.5 mag.
At the position of the afterglow (Xin et al., GCN 29235; Hu et al., GCN 29236; Kim et al., GCNs 29238, 29265, 29283; Lipunov et al., GCNs 29239, 29248; Horiuchi et al., GCN 29241; Breeveld et al., GCN 29247; Paek et al., GCN 29254; Smartt et al., GCN 29262; Anandagoda et al., GCN 29273; Mao et al., GCN 29275; Moskvitin & Vlasyuk, GCN 29277; Belikin et al., GCN 29286; Nakamura et al., GCN 29291; Kann et al., GCN 29318), we clearly detect the host galaxy in both filters (RA,DEC = 06:55:05.18,+64:40:33.7; J2000).
After removing the halo of a nearby star, we measure the following AB magnitudes:
r = 24.2 +/- 0.3
z = 22.1 +/- 0.2
calibrated against SDSS field stars.
We acknowledge the excellent support from the LBTO and LBT-INAF staff, particularly B. Rothberg, F. Cusano, and D. Paris, in obtaining these observations.