GRB 200131A
GCN Circular 27035
Subject
GRB 200131A: Tautenburg observations
Date
2020-02-11T15:39:37Z (6 years ago)
From
Sylvio Klose at TLS Tautenburg <klose@tls-tautenburg.de>
B. Stecklum, S. Klose, A. Nicuesa Guelbenzu, and C. Hoegner (all Tautenburg)
report:
We observed the field of GRB 200131A (T0=22:41:15 UT; Sbarufatti et al., GCN
26953) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6k
x 6k CCD camera and the wide V-band filter (VB). The transmission curve of this
filter closely follows the Gaia GBP filter.
Based on several Gaia DR2 stars in the field within 1 arcmin radius about the
afterglow position, we measure for the optical transient (Lipunov et al., GCN
26954; Butler et al., GCN 26957; Strausbaugh et al., GCN 26959; Gokuldass et
al., GCN 26960; Kuin et al., GCN 26962; Pozanenko et al., GCN 26964, 26965;
Watson et al., GCN 26977) the following Vega magnitudes:
mean time t = Jan 31, 23:12:15 UT; t-T0 = 00h 31m 00s; VB = 18.00 +/- 0.10
mean time t = Feb 01, 20:41:47 UT; t-T0 = 22h 00m 32s; VB = 21.85 +/- 0.30.
GCN Circular 26977
Subject
GRB 200131A: Further RATIR Optical Observations
Date
2020-02-03T19:22:08Z (6 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:
We observed the field of GRB 200131A (Sbarufatti et al., GCN 26953) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org)
on the 1.5m Harold Johnson Telescope at the Observatorio Astron��mico
Nacional on Sierra San Pedro M��rtir from 2020/02 2.10 to 2020/02 2.17
UTC (27.70 to 29.45 hours after the BAT trigger), obtaining a total of
1.42 hours exposure in the r and i bands, and from 2020/02 3.10 to
2020/02 3.12 UTC (51.69 to 52.28 hours after the BAT trigger), obtaining
a total of 0.49 hours exposure in the r and i bands.
The optical transient (Lipunov et al., GCN Circ. 26954, Butler et al.,
GCN Circ. 26957, Strausbaugh et al., GCN Circ. 26959, Gokuldass et al.,
GCN Circ. 26960, Pozanenko et al., GCN Circ. 26964 & 26965) is detected
on 2020/02/02 with:
r = 21.39 +/- 0.11
i = 21.39 +/- 0.07
and on 2020/02/03 with:
r = 22.26 +/- 0.29
i = 22.45 +/- 0.35
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 26975
Subject
Konus-Wind observation of GRB 200131A
Date
2020-02-03T16:09:21Z (6 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration, bright GRB 200131A
(Swift-BAT detection: Sbarufatti et al., GCN Circ. 26953;
Sakamoto et al., GCN Circ. 26967;
CALET Gamma-Ray Burst Monitor detection: Ricciarini et al., GCN 26972)
triggered Konus-Wind at T0=81673.507 s UT (22:41:13.507).
The burst light curve shows a bright, multi-peaked structure
which starts at ~T0-0.1 s and has a duration of ~3 s,
followed by a weaker episode at ~T0+32 s.
The emission is seen up to ~4 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200131_T81673/
As observed by Konus-Wind, the burst
had a fluence of 1.60(-0.08,+0.09)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.068 s,
of 1.64(-0.27,+0.28)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The spectrum of the brightest episode
(measured from T0 to T0+9.984 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.80(-0.09,+0.10)
and Ep = 228(-15,+17) keV (chi2 = 43/72 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.2
(chi2 = 43/71 dof).
The spectrum near the maximum count rate
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model:
with alpha = 0.01(-0.19,+0.21)
and Ep = 266(-22,+25) keV (chi2 = 49/38 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.8
(chi2 = 46/37 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 26972
Subject
GRB 200131A: CALET Gamma-Ray Burst Monitor detection
Date
2020-02-03T07:07:14Z (6 years ago)
From
Valentin Pal'shin at AGU <val@phys.aoyama.ac.jp>
S. Ricciarini (U of Florence),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The bright GRB 200131A detected by Swift (Sbarufatti et al.,
GCN Circ. 26953, Sakamoto et al., GCN Circ. 26967;
https://gcn.gsfc.nasa.gov/other/200131A.gcn3)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 22:41:11.299 UTC
on 31 January 2020. The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure which starts
at T+3.3 sec, peaks at T+3.8 sec and ends at T+6.4 sec.
The T90 and T50 durations measured by the SGM data are 2.2 +- 0.1 sec
and 1.4 +- 0.1 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1264545439/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.
GCN Circular 26967
Subject
GRB 200131A: Swift-BAT refined analysis
Date
2020-02-03T00:35:33Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), J. P. Norris (BSU),
D. M. Palmer (LANL), B. Sbarufatti (PSU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-200 to T+963 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 200131A (trigger #953689)
(Sbarufatti et al., GCN Circ. 26953). The BAT ground-calculated position is
RA, Dec = 3.067, 51.121 deg which is
RA(J2000) = 00h 12m 16.2s
Dec(J2000) = +51d 07' 15.6"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.
The mask-weighted light curve shows several bright overlapping
pulses that starts from ~T-3.5 s and ends at ~T+3. It is followed by
another weaker pulse at ~T+30 s and some weak emission that lasts
till ~T+60 s. The burst went out of the BAT FOV at T+472 s.
T90 (15-350 keV) is 32.74 +- 0.88 sec (estimated error including
systematics).
The time-averaged spectrum from T-3.45 to T+46.56 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
1.32 +- 0.04. The fluence in the 15-150 keV band is 7.0 +- 0.1 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+0.02 sec in the 15-150 keV band
is 26.9 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.
The spectral lag of the initial bright structure from ~T-2.5 s to ~T+3 s
is 49 (+3, -3) ms for the 100-350 keV to 25-50 keV bands, and 43 (+5, -7) ms
for the 50-100 keV to 15-25 keV bands. These values are consistent with
this of long GRBs.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/953689/BA/
GCN Circular 26965
Subject
GRB 200131A: ISON-Castelgrande optical observations
Date
2020-02-02T21:30:37Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), S. Schmalz (KIAM), V. Kim (AFIF, Pulkovo
Observatory), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM)
report on behalf of larger GRB follow-up collaboration:
We observed the field of the GRB 200131A (Sbarufatti al., GCN 26953)
with ORI-22 telescope of ISON-Castelgrande observatory starting on
Jan. 31 (UT) 23:11:28. We obtained 120 images of 60 s exposure in
Clear filter. The optical afterglow (Sbarufatti al., GCN 26953;
Lipunov al., GCN 26954; Butler al., GCN 26957; Strausbaugh al., GCN
26959; Kuin al., GCN 26962) is best detected in the stacked image of
the first 60 images.
Preliminary photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err.
(mid, days) (s)
2019-01-31 23:11:28 0.04353 Clear 60*60 18.35 0.25
The photometry is based on nearby USNO-B1.0 stars (R2 magnitude).
GCN Circular 26964
Subject
GRB 200131A: CDK700 optical observations
Date
2020-02-02T21:01:36Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), V. Kim (AFIF, Pulkovo Observatory), I. Reva (AFIF),
M. Krugov (AFIF), E. Mazaeva (IKI), A. Volnova (IKI) report on behalf
of larger GRB IKI FuN collaboration:
We observed the field of the GRB 200131A (Sbarufatti al., GCN 26953)
with CDK700 (0.7m) telescope of Assy-Turgen observatory starting on
Feb. 01 (UT) 14:58:49 in R-filter. We marginally detect the
optical afterglow (Sbarufatti al., GCN 26953; Lipunov al., GCN 26954;
Butler al., GCN 26957; Strausbaugh al., GCN 26959; Kuin al., GCN 26962).
Preliminary photometry of the afterglow is following.
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2019-02-01 14:58:49 0.76733 R 14*360 21.4 0.3 21.5
The photometry is based on nearby USNO-B1.0 stars (R2 magnitudes).
GCN Circular 26962
Subject
GRB 200131A: Swift/UVOT Detection
Date
2020-02-01T14:37:48Z (6 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and B. Sbarufatti (PSU)report on behalf of
the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200131A
78 s after the BAT trigger (Sbarufatti et al., GCN Circ. 26953).
A source consistent with the XRT position (Goad et al. GCN Circ. 26956)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 00:12:22.57 = 3.09405 (deg.)
Dec (J2000) = +51:07:00.3 = 51.11675 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
The source has been detected also by MASTER (Lipunov et al. GCN Circ. No.
26954), RATIR (Butler et al., GCN Circ. No. 26957), MacDonalds Observatory
(Strausbaugh et al., GCN Circ. No. 26959), and VIRT (Gokuldass et al.,
GCN Circ. No. 26960.
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 78 227 147 15.47 +/- 0.02
v 4281 5919 393 19.57 +/- 0.28
b 5103 5303 197 19.53 +/- 0.16
u 290 323 32 16.09 +/- 0.08
w1 4692 4892 197 18.48 +/- 0.18
m2 4486 6124 393 18.98 +/- 0.20
w2 4076 5714 393 19.06 +/- 0.19
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.17 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 26961
Subject
GRB 200131A: Swift-XRT refined Analysis
Date
2020-02-01T08:55:16Z (6 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne
(U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) ,
M. Capalbi (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU) and B.
Sbarufatti report on behalf of the Swift-XRT team:
We have analysed 6.1 ks of XRT data for GRB 200131A (Sbarufatti et al.
GCN Circ. 26953), from 61 s to 17.4 ks after the BAT trigger. The data
comprise 249 s in Windowed Timing (WT) mode (the first 5 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN Circ. 26956). We cannot determine at the present time whether the
source is fading.
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.83 (+0.04, -0.03). The
best-fitting absorption column is consistent with the Galactic value
of 1.8 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.81 (+0.15, -0.14) and a best-fitting absorption
column of 2.3 (+0.6, -0.4) x 10^21 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 4.0 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.3 (+0.6, -0.4) x 10^21 cm^-2
Galactic foreground: 1.8 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.81 (+0.15, -0.14)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00953689.
This circular is an official product of the Swift-XRT team.
GCN Circular 26960
Subject
GRB 200131A: VIRT optical transient detection
Date
2020-02-01T05:23:11Z (6 years ago)
From
Priyadarshini Gokuldass at U. of the Virgin Islands <priyadass.94@gmail.com>
P. Gokuldass (UVI), D. Morris (UVI), N. Orange (OrangeWave Innovative
Science, LLC), A. Cucchiara (College of Marin), R. Strausbaugh (UVI) report:
We observed the field of GRB 200131A (Sbarufatti et al. GCN 26953) with the
0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin
Islands' Etelman Observatory on 01-31-2020 starting at 23:28:45 UT (T+67
minutes). We performed a series of exposures in R filter. The weather
conditions were variable during the hours of observation and the zenith
angle at the start of observations was 54 degrees and setting. The midpoint
of the exposures is ~T+1.6 hrs. We observed the Swift XRT position with a
20'x20' field of view
We detect an uncatalogued source consistent with the UVOT position
(Sbarufatti et al. GCN 26953) and MASTER OT position (Lipunov et al. 26954)
with magnitude:
R= 16.8 +/- 0.2
The magnitude 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 26959
Subject
GRB 200131A: LCO Optical Detection
Date
2020-02-01T05:13:29Z (6 years ago)
From
Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh@uvi.edu>
R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration:
We observed Swift GRB 200131A (Kennea et al., GCN 26953) with the LCO 1-m Sinistro instrument at the McDonald Observatory, Texas, USA site on January 31, from 01:59 to 02:22 UT (corresponding to 3.1 to 3.6 hours after the GRB trigger time) with the Bessel R and I filters.
We performed a series of 5x120s exposures in each band. We detect a source in the Swift-BAT refined error region (Evans et al., GCN 26956) that is not present in either USNO-B1.0 or 2MASS surveys with the following magnitudes:
R = 19.75 +/- 0.13
I = 19.31 +/- 0.14
This flux measurement is calibrated against several USNO-B1.0 objects near the GRB location and is not corrected for Galactic Extinction.
GCN Circular 26958
Subject
GRB 200131A: KAIT Optical Upper Limit
Date
2020-02-01T04:34:37Z (6 years ago)
From
Weikang Zheng at UC Berkeley <weikang@berkeley.edu>
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 200131A (Sbarufatti et al.,
GCN 26953) starting at 4.15 hours after the burst. Observations
were performed in the clear (roughly R) filters, a total of 11
images were obtained and the exposure time was 60 s per image.
We do not detect the optical afterglow reported by UVOT (Sbarufatti
et al., GCN 26953; see also Lipunov et al. GCN 26954; Butler
et al. GCN 26957), neither in single image nor in the co-add image.
The limiting magnitude estimated from our coadd image is about 19.5 mag.
GCN Circular 26957
Subject
GRB 200131A: RATIR Optical Observations
Date
2020-02-01T04:26:12Z (6 years ago)
From
Nat Butler at UC berkeley <natxbutler@gmail.com>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora
Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:
We observed the field of GRB 200131A (Sbarufatti et al., GCN 26953) with
the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on
the 1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional
on Sierra San Pedro M��rtir from 2020/02 1.10 to 2020/02 1.14 UTC (3.79 to
4.61 hours after the BAT trigger), obtaining a total of 0.64 hours exposure
in the r and i bands.
The optical transient (see, also, Lipunov et al., GCN 26954) is
well-detected. We find:
r = 19.97 +/- 0.04
i = 19.75 +/- 0.02
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 26956
Subject
GRB 200131A: Enhanced Swift-XRT position
Date
2020-02-01T03:59:52Z (6 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 2283 s of XRT Photon Counting mode data and 6 UVOT
images for GRB 200131A, 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 = 3.09439, +51.11676 which is equivalent
to:
RA (J2000): 00h 12m 22.65s
Dec (J2000): +51d 07' 00.4"
with an uncertainty of 1.5 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 26954
Subject
GRB 200131A: MASTER optical transient detection
Date
2020-01-31T23:13:16Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, N.Tyurina, E. Gorbovskoy, O.Gress, V.Kornilov, P.Balanutsa,A.Kuznetsov,
V. Vladimirov, D. Vlasenko, F.Balakin, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva,
D. Kuvshinov, V.Shumkov (Lomonosov Moscow State University, SAI, Physics Department),
D. Buckley(South African Astronomical Observatory),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA),
H. Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University)
MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,v. 2010, 30L)
started Swift GRB 200131A (Sbarufatti et al. GCN 26953) alert observation
50s after trigger time (Lipunov et al. GCN 26952) at MASTER-Tunka and 78s
after trigger time at MASTER-IAC.
MASTER auto-detection system found
MASTER OT J001222.56+510700.3 at
RA,Dec(2000) = 00h 12m 22.56s , +51d 07m 00s.3
with m_OT=14.5 (unfiltered) at the first exposition (10s)
with optical decay ,
also detected by Swift UVOT (GCN 26953)
Observation and reduction will be continued
GCN Circular 26953
Subject
GRB 200131A: Swift detection of a burst with an optical counterpart
Date
2020-01-31T22:53:30Z (6 years ago)
From
Jamie A. Kennea at PSU/Swift-XRT <kennea@swift.psu.edu>
B. Sbarufatti (PSU), D. N. Burrows (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. J. Klingler (PSU), S. Laha (GSFC/UMBC/CRESST),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. H. Siegel (PSU)
and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels
Swift Observatory Team:
At 22:41:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200131A (trigger=953689). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 3.095, +51.124 which is
RA(J2000) = 00h 12m 23s
Dec(J2000) = +51d 07' 25"
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 5 sec. There might be a small
pulse at T+30 s. The peak count rate was ~60000 counts/sec
(15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 22:42:24.7 UT, 68.7 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 3.0942, 51.1158 which is equivalent to:
RA(J2000) = 00h 12m 22.61s
Dec(J2000) = +51d 06' 56.9"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
location is 29 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 3.76e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 77 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 00:12:22.57 = 3.09403
DEC(J2000) = +51:07:00.4 = 51.11678
with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.6
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.44 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.17.
Burst Advocate for this burst is B. Sbarufatti (bxs60 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/)