GRB 210102B
GCN Circular 29223
Subject
GRB 210102B: MAXI/GSC detection
Date
2021-01-02T12:38:16Z (4 years ago)
From
Motoko Serino at RIKEN/MAXI <motoko@crab.riken.jp>
C. Guo (RIKEN), M. Serino (AGU), H. Negoro,
M. Nakajima, M. Aoki, K. Kobayashi, R. Takagi, K, Asakura, K, Seino (Nihon U.),
T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, H. Nishida, K. Komachi, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.),
M. Shidatsu (Ehime U.),
N. Kawai, R. Adachi, M. Niwano, R. Hosokawa (Tokyo Tech),
S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA),
Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, U. Goto, R. Uematsu (Kyoto U.),
H. Tsunemi (Osaka U.),
M. Yamauchi, K. Kurogi, K. Miike (Miyazaki U.),
T. Kawamuro (NAOJ),
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU),
M. Sugizaki (NAOC)
report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source at 2021-01-02T09:03:48 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (353.323 deg, -21.086 deg) = (23 33 18, -21 05 10) (J2000)
with a statistical 90% C.L. circular error region
with a radius of 0.5 deg.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 238 +- 31 mCrab
(2.0-4.0keV, 1 sigma error).
There was no significant excess flux in the next transit at 10:36 UT
with an upper limit of 20 mCrab.
GCN Circular 29224
Subject
GRB 210102B: Tiled Swift observations
Date
2021-01-02T14:40:06Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 210102B. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00097
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 29230
Subject
GRB 210102B: Swift-XRT observations
Date
2021-01-03T13:44:24Z (4 years ago)
From
Paolo D'Avanzo at INAF - OAB <paolo.davanzo@inaf.it>
D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne
(U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), T.
Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 210102B (Guo et al. GCN Circ. 29223) in a series of
observations tiled on the sky. The total exposure time is 1.3 ks,
distributed over 7 tiles; the maximum exposure at a single sky location
was 406 s. The data were collected between T0+19.7 ks and T0+26.0 ks,
and are entirely in Photon Counting (PC) mode.
One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:
Source 1:
RA (J2000.0): 353.8173 = 23:35:16.14
Dec (J2000.0): -21.0821 = -21:04:55.6
Error: 5.5 arcsec (radius, 90% conf.)
Count-rate: 0.030 [+0.016, -0.012] ct s^-1
Distance: 1289 arcsec from MAXI position.
The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00097.
This circular is an official product of the Swift-XRT team.
GCN Circular 29240
Subject
GRB 210102B: Assy optical observations
Date
2021-01-04T18:06:38Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), S. Belkin (IKI), V. Kim (FAI, Pulkovo Observatory),
M. Krugov (FAI) report on behalf of GRB IKI FuN:
We observed MAXI GRB 210102B (Guo et al., GCN 29223) with AZT-20
telescope of Assy-Turgen observatory starting on Jan. 03 (UT) 13:00:53.
i.e. ~1.6 days after trigger. At the place of the only one of XRT
candidates (Burrows et al., GCN 29230) in the localization area of MAXI
(Guo et al., GCN 29223) we clearly detect the optical object in
coordinates (J2000) 23:35:15.88 -21:04:55.5 with uncertainness of 0.6
arcsec in both coordinates.
Preliminary photometry of the object is following
Date UT start t-T0 Filter Exp. OT Err. UL (3sigma)
(mid, days) (s)
2021-01-03 13:00:53 1.19068 r'(AB) 75*60 22.2 0.2 23.0
The photometry is based on the stars of PanSTARRS-PS1
RA DEC r'
23:35:20.67802 -21:04:16.4688 19.656
23:35:47.99017 -21:11:53.6544 17.807
At this tome we cannot confirm variability of the source. We can suggest
the object might be related to GRB 210102B.
GCN Circular 29244
Subject
GRB 210102B: Tiled Swift observations
Date
2021-01-04T21:35:37Z (4 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 210102B. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00098
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 29270
Subject
GRB 210102B: Assy optical afterglow identification
Date
2021-01-06T15:55:15Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), S. Belkin (IKI), V. Kim (FAI, Pulkovo Observatory),
M. Krugov (FAI) report on behalf of GRB IKI FuN:
We continued observations of XRT candidate (Burrows et al., GCN 29230)
of MAXI GRB 210102B (Guo et al., GCN 29223) with AZT-20 telescope of
Assy-Turgen observatory starting on Jan. 05 (UT) 13:00:53, i.e. ~3.2
days after trigger. At the place of the only one of XRT candidate
(Burrows et al., GCN 29230) we do not detect the optical object found
early (Pozanenko et al., GCN 29240).
Preliminary photometry of the field is following
Date UT start t-T0 Filter Exp. OT Err. UL (3sigma)
(mid, days) (s)
2021-01-05 13:00:53 3.20177 r'(AB) 76*60 n/d n/d 23.1
The photometry is based on the stars of PanSTARRS-PS1
RA DEC r'
23:35:20.67802 -21:04:16.4688 19.656
23:35:47.99017 -21:11:53.6544 17.807
We confirm the optical object reported in GCN 29240 as an afterglow of
GRB 210102B.
GCN Circular 29271
Subject
GRB 210102B: further Swift-XRT observations
Date
2021-01-06T17:28:28Z (4 years ago)
From
Paolo D'Avanzo at INAF-OAB <pda.davanzo@gmail.com>
P. D'Avanzo, M.G. Bernardini, A. Melandri, T. Sbarrato (INAF-OAB), P.A. Evans (U. Leicester)
and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift-XRT team:
Swift-XRT obtained further observations of the field of the MAXI-detected burst GRB 210102B
(Guo et al. GCN Circ. 29223). The data were collected between T0+209.5 ks and T0+312.5 ks
for a total exposure time of 2.5 ks, and are entirely in Photon Counting (PC) mode.
Source 1 (Burrows et al., GCN Circ. 29230) is not detected down to a 3sigma upper limit of 0.004 ct/s.
The source therefore has faded (with 2.2 sigma significance) with respect to the previous detection level
(0.030 [+0.016, -0.012] ct s^-1 between T0+19.7 ks and T0+26.0 ks; Burrows et al., GCN Circ. 29230).
We propose this source as the GRB X-ray afterglow, in agreement with the results of the optical observations
reported by Pozanenko et al. (GCN Circ. 29270).