GRB 201020A
GCN Circular 28789
Subject
GRB 201020A: 1.3m DFOT, optical upper limits
Date
2020-10-27T05:34:21Z (5 years ago)
From
Amit Kumar at ARIES, India <amitkundu515@gmail.com>
Amit Kumar (ARIES), Rahul Gupta (ARIES), Ankur Ghosh (ARIES), Dimple
(ARIES), Kaushal Sharma (ARIES), Amar Aryan (ARIES), Shashi B. Pandey
(ARIES), and Kuntal Misra (ARIES) report:
We observed the field of GRB 201020A (E. Ambrosi et al., GCN 28696)
with the 1.3m Devasthal Fast Optical Telescope (DFOT)
at Devasthal observatory of Aryabhatta Research Institute of
observational sciencES (ARIES), India.
Multiple frames of the GRB field were obtained in the Bessel R and
I-bands (15*120sec in each filter).
Preliminary photometry on stacked images were performed and calibrated
against nearby USNO-B1 stars.
We do not detect any OT candidate (see Adachi et al. GCN 28697;
Lipunov et al. GCN 28700; Fu et al. GCN 28701;
Belkin et al. 28703; Pankov et al. GCN 28708; Kumar et al. GCN 28711;
Paek et al. 28713; Kann et al. 28717; Gokuldass et al. 28737; Siegel
et al. 28742 and Kumar et al. GCN 28747) within the enhanced XRT
position (Osborne et al., GCN 28698).
The 3-sigma upper limits at the location of the afterglow are as follows:
DATE Start UT Filter Exposure(sec) Lim_mag (3-sigma)
2020-10-24 12:51:08 I 15*120 >22.1
2020-10-24 13:23:45 R 15*120 >22.5
The estimated magnitudes have not been corrected for the Galactic
extinction in the direction of the GRB. This massage may be cited.
GCN Circular 28747
Subject
GRB 201020A: GROWTH-India Telescope late-time optical upper limit
Date
2020-10-22T15:21:06Z (5 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
H. Kumar (IITB), J. Stanzin (IAO), V. Bhalerao(IITB), G. C. Anupama (IIA),
S. Barway (IIA), report on behalf of the GROWTH-India collaboration:
We observed GRB 201020A reported by Swift-BAT (E. Ambrosi et al., GCN
#28696) with 0.7m GROWTH-India telescope. The field was observed in the
SDSS r��� filter with multiple 300-sec exposures. We obtained the following
late time upper limit:
----------------------------------------------------------------------
JD (mean)| T-T0(hrs) | Filter | Exposure (sec) | Lim_mag (5-sigma) |
----------------------------------------------------------------------
2459144.094375 | 32.47 | r��� | 14 * 300 (stacked) | > 21.47 |
----------------------------------------------------------------------
This upper limit is consistent with our best-fit power-law decay from H.
Kumar et al., GCN #28711. Magnitudes are in the AB system and calibrated
against PanSTARRs PS1 data release, (Flewelling et al., 2018).
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 28744
Subject
Konus-Wind detection of GRB 201020A
Date
2020-10-22T12:51:04Z (5 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 201020A
(Swift-BAT trigger #1000926: Ambrosi et al., GCN 28696;
Sakamoto et al., GCN 28705; T0(BAT)=05:47:26.16 UT;
Fermi-GBM observation: Bissaldi et al., GCN 28706)
was detected by Konus-Wind (KW) in the waiting mode.
The burst light curve shows a single emission episode
with a duration of ~ 15 s.
The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB201020A/
As observed by Konus-Wind, the burst had a fluence of
1.38(-0.23,0.45)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(BAT)+16.5 s, of 1.34(-0.28,+0.47)x10^-7 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The K-W 3-channel time-integrated spectrum
(from ~T0(BAT)+10.6 s to ~T0(BAT)+25.3 s)
is best described by simple power-law model
with photon index of -2.41(-0.12,+0.17), chi2=0.06/1 dof.
Assuming the redshift z=2.903 (Kann et al., GCN 28717)
and a standard cosmology model with H_0 = 67.3 km/s/Mpc,
Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~2.6x10^52 erg,
and the peak luminosity L_iso is ~1.0x10^52 erg/s.
All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.
GCN Circular 28742
Subject
GRB 201020A: Swift/UVOT Observations
Date
2020-10-22T12:16:21Z (5 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and E. Ambrosi (INAF-IASFPA)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 201020A
144 s after the BAT trigger (Ambrosi et al., GCN Circ. 28696).
We confirm the fading source initially reported by Ambrosi et al. and
since confirmed by numerous observations (Adachi et al., GCN
Circ. 28697; Fu et al., GCN Circ. 28701; Belkin et al., GCN Circ. 28703,
Pankow et al. GCN Circ. 28708, Kumar et al. GCN Circ. 28711, Paek et al.
GCN Circ. 28713). The afterglow is not detected in UVOT's NUV filters,
which would be consistent with the redshift of 2.9 reported by Kann et al.
(GCN Circ. 28717).
The preliminary UVOT position is:
RA (J2000) = 17:24:54.66 = 261.22773 (deg.)
Dec (J2000) = +31:25:42.1 = 31.42837 (deg.)
with an estimated uncertainty of 0.44 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) 145 294 147 18.19+/-0.05
white 583 775 38 19.39+/-0.23
white 9805 10713 885 19.71+/-0.09
white 131168 131712 531 >21.48
v 632 826 38 17.91+/-0.28
v 21653 22150 485 19.26+/-0.28
v 34473 35292 798 19.86+/-0.29
v 125782 126429 629 >19.99
b 558 750 38 >19.30
b 22822 23469 630 20.35+/-0.21
b 39219 39998 759 21.05+/-0.36
b 130256 131163 885 >20.60
u (fc) 303 552 245 19.76+/-0.27
u 706 726 19 >18.42
u 29427 29557 128 >19.69
uvw1 681 876 38 >18.16
uvw1 28521 29420 885 >20.42
uvm2 656 676 19 >17.06
uvm2 27614 28514 885 >20.29
uvw2 608 800 38 >18.04
uvw2 10719 34466 1329 >20.71
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 28737
Subject
GRB 201020A: VIRT optical observations
Date
2020-10-22T02:04:54Z (5 years ago)
From
Priyadarshini Gokuldass at U. of the Virgin Islands <priyadass.94@gmail.com>
P. Gokuldass (UVI), R. Strausbaugh (UVI), N. Orange (OrangeWave Innovative
Science, LLC), D. Morris (UVI), A. Cucchiara (UVI/College of Marin) report:
We observed the field of GRB201020A (Ambrosi et al., GCN 28696) with the
0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin
Islands' Etelman Observatory on 10-20-2020 starting at 23:11:52.3 UT (T+17.2
hrs). We performed a series of exposures in R filter with a total exposure
of 3140 s. The weather conditions were clear during the hours of
observation with an average airmass of 2.1.
We find no new source within the enhanced XRT position error circle
(Osborne et al., 28698) and report the following 3-sigma upper limit:
T_mid ||Exposure ||Filter ||Limit
T+18 hrs ||3140s ||R ||>20.6
The limit is estimated from comparison to nearby USNO B1 stars and is not
corrected for Galactic extinction. The VIRT is still in the commissioning
phase.
This work is supported by NASA-MUREP-MIRO grant NNX15AP95A, NSF EiR AST
Award 1901296, and NSF HBCU-UP AST Award 1831682. This message can be cited.
GCN Circular 28717
Subject
GRB 201020A: Redshift from GTC/OSIRIS
Date
2020-10-21T10:30:41Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), M. Blazek, J. F. Agui Fernandez, C. C. Thoene (all
HETH/IAA-CSIC), G. Lombardi (GRANTECAN, IAC) and A. Tejero (GRANTECAN)
report:
We observed the afterglow (Ambrosi et al., GCN#28696; Adachi et al.,
GCN#28697; Fu et al., GCN#28701; Belkin et al., GCN#28703; Pankov et
al., GCN#28708; Kumar et al., GCN#28711; Paek et al., GCN#28713) of GRB
201020A (Ambrosi et al., GCN#28696; Sakamoto et al., GCN#28705; Bissaldi
et al., GCN#28706) with the 10.4m GTC telescope, at Roque de los
Muchachos Observatory (La Palma, Spain) equipped with OSIRIS. The
observation started on 20 October 2020 at 20:08 UT (14.34 hrs after the
GRB onset) and consisted of 4 x 900s with the R1000B grism, covering the
wavelength range between 3700 and 7800 AA. Observations were taken under
inclement conditions, with bad seeing and thick clouds passing through.
The spectrum shows a clear continuum, consistent with the Lyman forest,
Ly-alpha, SiII, OI, CII, SiIV, CIV, FeII, FeII*, and AlII, all at a
common redshift of z = 2.903, which we identify as the redshift of the
GRB.
GCN Circular 28713
Subject
GRB 201020A: DOAO optical afterglow observations
Date
2020-10-21T04:51:18Z (5 years ago)
From
Gregory SungHak Paek at SNU <shpaek@astro.snu.ac.kr>
Gregory S.H. Paek (CEOU/SNU), Myungshin Im (CEOU/SNU), Taewoo Kim, and
Wonseok Kang (DOAO) on behalf of a larger collaboration
We observed the optical counterpart of GRB 201020A (E. Ambrosi et al., GCN
#28696; R. Adachi et al., GCN #28697; J.P. Osborne et al., GCN #28698; V.
Lipunov et al., GCN #27800, S.Y. Fu et al., GCN #28701; S. Belkin et al.,
GCN #28703, T. Pankov et al., GCN #28708, and H. Kumar et al., GCN #28711)
with the 1-m class telescope in Deokheung Optical Astronomy Observatory
(DOAO). We calibrated flux with PS1 catalog and use AB magnitude system.
---------------------------------------------------------------------
Mid Date[UT] Mid t-t0[days] Filter Exp.time[s] Mag Error
---------------------------------------------------------------------
2020-10-20 10:28:07 0.195 V 300*3 19.361 0.059
2020-10-20 10:33:21 0.199 R 300*3 19.006 0.042
2020-10-20 10:38:35 0.202 I 300*3 18.767 0.039
t0 : 2020-10-20 05:47:26 UT (E. Ambrosi et al., GCN #28696)
The magnitudes are not corrected for galactic extinction.
GCN Circular 28711
Subject
GRB 201020A: GROWTH-India Telescope optical observations
Date
2020-10-21T02:17:35Z (5 years ago)
From
Varun Bhalerao at Indian Inst of Tech <varunb@iitb.ac.in>
H. Kumar(IITB), J. Stanzin (IIA), V. Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA), report on behalf of the GROWTH-India collaboration:
We followed up GRB 2010210A (E. Ambrosi et al., GCN #28696; also see:- R. Adachi et al., GCN #28697; J.P. Osborne et al., GCN #28698; V. Lipunov et al., GCN #27800, S.Y. Fu et al., GCN #28701; S. Belkin et al., GCN #28703 and T. Pankov et al., GCN #28708) with 0.7m GROWTH-India telescope. We obtained 300-sec exposures in the SDSS r��� filter starting at 2020-10-20T13:00:50.42 UT (~7.22 hrs after the burst). We clearly detected uncataloged sources at a position consistent with E. Ambrosi et al., GCN #28696.
Here are the photometric results from GIT observations:-
------------------------------------------------------------------
JD (END) | T_end-T0(hrs) | Filter | Mag |
------------------------------------------------------------------
2459143.04576 | 7.31 | r | 19.43 +/- 0.06
2459143.04943 | 7.39 | r | 19.49 +/- 0.05
2459143.05670 | 7.57 | r | 19.52 +/- 0.04
2459143.06046 | 7.66 | r | 19.59 +/- 0.04
2459143.06406 | 7.75 | r | 19.63 +/- 0.04
2459143.06764 | 7.83 | r | 19.65 +/- 0.04
-----------------------------------------------------------------
Combining our photometric results with r��� measurements of S.Y. Fu et al., (GCN #28701), S. Belkin et al., (GCN #28703), and T. Pankov et al., (GCN #28708) we conclude that the source is fading with a power-law index of 1.6 +/- 0.2. Given the fast fading, we encourage the follow-up of the source. The magnitudes are not corrected for galactic extinction.
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 28708
Subject
GRB 201020A: CrAO/ZTSH optical observations
Date
2020-10-21T00:03:22Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE), A. Pozanenko (IKI), V. Rumyantsev (CrAO), S. Belkin
(IKI), A. Volnova (IKI) report on behalf of IKI GRB FuN:
We observed the GRB 201020A (Ambrosi et al., GCN 28696) with ZTSH 2.6m
telescope of CrAO observatory starting on Oct. 20 (UT) 16:06:30. The
optical afterglow (Ambrosi et al., GCN 28696; Adachi et al., GCN
28697; Fu et al., GCN 28701; Belkin et al., GCN 28703) is clearly
detected in R filter.
Preliminary photometry of the afterglow in a combined image is following
Date UT start t-T0 Filter Exp. OT err UL(3sigma)
(mid, days) (s)
2018-10-20 16:06:30 0.42991 R 30*120 20.00 0.10 21.5
The photometry is based on several nearby USNO-B1.0 (R2) stars.
GCN Circular 28707
Subject
GRB 201020A: Swift-XRT refined Analysis
Date
2020-10-20T22:29:25Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU),
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB), P. D'Avanzo
(INAF-OAB) and E. Ambrosi report on behalf of the Swift-XRT team:
We have analysed 6.9 ks of XRT data for GRB 201020A (Ambrosi et al. GCN
Circ. 28696), from 148 s to 35.3 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Osborne et al. (GCN Circ. 28698).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.71 (+/-0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.06 (+0.18, -0.17). The
best-fitting absorption column is 8.6 (+4.4, -3.9) x 10^20 cm^-2, in
excess of the Galactic value of 3.7 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 3.2 x 10^-11 (3.9 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 8.6 (+4.4, -3.9) x 10^20 cm^-2
Galactic foreground: 3.7 x 10^20 cm^-2
Excess significance: 2.1 sigma
Photon index: 2.06 (+0.18, -0.17)
If the light curve continues to decay with a power-law decay index of
0.71, the count rate at T+24 hours will be 0.015 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.7 x
10^-13 (5.7 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/01000926.
This circular is an official product of the Swift-XRT team.
GCN Circular 28706
Subject
GRB 201020A: Fermi GBM observation
Date
2020-10-20T21:02:13Z (5 years ago)
From
Christian Malacaria at NASA-MSFC/USRA <cmalacaria@usra.edu>
E. Bissaldi (Politecnico and INFN Bari), C. Malacaria (NASA-MSFC/USRA)
and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 05:47:45.18 UT on 20 October 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 201020A (trigger 624865670 / 201020241),
which was also detected by the Swift/BAT (Ambrosi et al. 2020, GCN 28696).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 66 degrees.
The GBM light curve shows a single emission episode
with a duration (T90) of about 22 s (50-300 keV).
The time-averaged spectrum from T0-10.2s to T0+10.2 s is
best fit by a simple power law function with index -1.83 +/- 0.04.
The event fluence (10-1000 keV) in this time interval is
(2.47 +/- 0.17)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-3.6 s in the 10-1000 keV band
is 3.48 +/- 0.14 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 28705
Subject
GRB 201020A: Swift-BAT refined analysis
Date
2020-10-20T20:08:10Z (5 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
T. Sakamoto (AGU), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 201020A (trigger #1000926)
(Ambrosi et al., GCN Circ.28696). The BAT ground-calculated position is
RA, Dec = 261.239, 31.428 deg which is
RA(J2000) = 17h 24m 57.4s
Dec(J2000) = +31d 25' 41.8"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 90%.
The mask-weighted light curve shows a single symmetrical peak starting at ~T+8 sec,
peaking at T+17 sec, and decaying to background by T+26 sec.
T90 (15-350 keV) is 14.17 +- 4.68 sec (estimated error including systematics).
The time-averaged spectrum from T+8.23 to T+30.17 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.25 +- 0.14. The fluence in the 15-150 keV band is 9.2 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+17.17 sec in the 15-150 keV band
is 2.1 +- 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/1000926/BA/
GCN Circular 28703
Subject
GRB 201020A: Assy optical observations
Date
2020-10-20T17:50:28Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), V. Kim (AFIF, Pulkovo Observatory),
M. Krugov (AFIF), N. Pankov (HSE), A. Volnova (IKI) report on behalf
of IKI GRB FuN:
We observed the filed of GRB 201020A (Ambrosi et al., GCN 28696) with
AZT-20 telescope of Assy-Turgen observatory starting on (UT) Oct. 20
(Ut) 14:00:44 (UT) in r'-filter. We clearly detect optical afterglow
(Ambrosi et al., GCN 28696; Adachi et al., GCN 28697; Fu et al.,
GCN 28701).
Preliminary photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err. UL (3sigma)
(mid, days) (s)
2020-10-20 14:00:44 0.36688 r'(AB) 70*60 19.70 0.03 23.8
The photometry is based on the nearby stars of PanSTARRS-PS1 catalog.
SDSS-DR12_id r
J172452.73+312623.9 18.459
J172455.96+312344.8 18.057
J172452.57+312302.1 17.618
J172456.76+312315.5 16.876
GCN Circular 28701
Subject
GRB 201020A: Nanshan/NEXT optical observations
Date
2020-10-20T16:08:23Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Y. Fu (NAOC), Z.P. Zhu (NAOC, HUST), X. Liu, D. Xu (NAOC), X. Gao
(Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 201020A (Ambrosi et al., GCN 28696) using
the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained
15x120s frames in the Sloan r-band, starting at 13:48:25 UT on
2020-10-20, i.e., 8.02 hr after the BAT trigger.
The optical afterglow (Ambrosi et al., GCN 28696; Adachi et al., GCN
28697) of the burst is clearly detected in our stacked image, with r =
19.69 +/- 0.06 mag at T_mid = 0.3461 day post-burst, calibrated with
nearby PS1 stars.
GCN Circular 28700
Subject
Swift GRB 201020A: Global MASTER-Net observations report
Date
2020-10-20T16:00:40Z (5 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) was pointed to the Swift GRB 201020A ( E. Ambrosi et al., GCN 28696) errorbox 35426 sec after notice time and 35521 sec after trigger time at 2020-10-20 15:39:27 UT, with upper limit up to 17.6 mag. Observations started at twilight. The observations began at zenith distance = 32 deg. The sun altitude is -9.4 deg.
The galactic latitude b = 31 deg., longitude l = 55 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1464820
We obtain a following upper limits.
Tmid-T0 | Site |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________
35612 | MASTER-Tavrida | C | 180 | 16.4 |
36013 | MASTER-Tavrida | C | 180 | 17.6 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 28698
Subject
GRB 201020A: Enhanced Swift-XRT position
Date
2020-10-20T13:05:56Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 729 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 201020A, 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 = 261.22827, +31.42804 which is equivalent
to:
RA (J2000): 17h 24m 54.78s
Dec (J2000): +31d 25' 40.9"
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 28697
Subject
GRB 201020A: MITSuME Akeno optical observation
Date
2020-10-20T10:25:22Z (5 years ago)
From
Adachi Ryo at Tokyo Institute of Tech <adachi@hp.phys.titech.ac.jp>
R. Adachi, R. Hosokawa, K. L. Murata, 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 201020A (E. Ambrosi et al.,GCN Circular
#28696) 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 2020-10-20 08:31:00 UT. The first 28 images
were heavily affected by twilight at Akeno Observatory. We detected
the point source at the position consistent with the afterglow
detected previously (E. Ambrosi et al. GCN #28696).
We measured the magnitudes as follows.
T0+[min] MID-UT T-EXP[sec] measured magnitudes
------------------------------------------------------------------------------------------------
196 09:15:39 1260 g'=19.4+/-0.2, Rc=18.4+/-0.1, Ic=18.4+/-0.2
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 and 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., accepted for publication in PASJ,
https://arxiv.org/abs/2008.11486; https://github.com/MNiwano/Eclaire).
GCN Circular 28696
Subject
GRB 201020A: Swift detection of a burst with an optical counterpart.
Date
2020-10-20T05:59:53Z (5 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC),
N. J. Klingler (PSU), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC),
K. L. Page (U Leicester), T. Sakamoto (AGU), B. Sbarufatti (PSU) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 05:47:26 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 201020A (trigger=1000926). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 261.246, +31.425 which is
RA(J2000) = 17h 24m 59s
Dec(J2000) = +31d 25' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single-peaked
structure with a duration of about 20 sec. The peak count rate
was ~1800 counts/sec (15-350 keV), at ~17 sec after the trigger.
The XRT began observing the field at 05:49:47.6 UT, 141.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 261.2279,
31.4288 which is equivalent to:
RA(J2000) = 17h 24m 54.71s
Dec(J2000) = +31d 25' 43.8"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 57 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 3.70
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 144 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 17:24:54.67 = 261.22779
DEC(J2000) = +31:25:42.0 = 31.42834
with a 90%-confidence error radius of about 0.62 arc sec. This position is 5.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.14 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.04.
Burst Advocate for this burst is E. Ambrosi (elena.ambrosi AT 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/)