GRB 200127A
GCN Circular 26895
Subject
GRB 200127A: Swift detection of a burst
Date
2020-01-27T15:04:17Z (5 years ago)
From
Caryl Gronwall at PSU/Swift-UVOT <caryl@swift.psu.edu>
M. J. Moss (GWU), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 14:44:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200127A (trigger=952791). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 295.204, +44.910 which is
RA(J2000) = 19h 40m 49s
Dec(J2000) = +44d 54' 35"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). As is usual with an image trigger, the available
BAT light curve shows no significant structure.
The XRT began observing the field at 14:46:52.1 UT, 140.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 295.19447,
44.90030 which is equivalent to:
RA(J2000) = 19h 40m 46.67s
Dec(J2000) = +44d 54' 01.1"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 42 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 2.17
x 10^21 cm^-2 (Willingale et al. 2013).
The initial flux in the 2.5 s image was 9.40e-10 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 250 seconds with the U filter starting
309 seconds after the BAT trigger. No credible afterglow candidate has been
found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the
XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The
8'x8' region for the list of sources generated on-board covers 100% of the XRT
error circle. The list of sources is typically complete to about 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.16.
Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com).
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 26899
Subject
GRB 200127A: AbAO optical upper limit
Date
2020-01-27T18:59:15Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO ), V. R.
Ayvazian (AbAO ), G.V. Kapanadze (AbAO), E. Mazaeva (IKI), A. Volnova
(IKI), I. Molotov (KIAM) report on behalf of larger IKI GRB follow-up
collaboration:
We observed the GRB 200127A (Moss et al., GCN 26895) with AS-32 (0.7m)
telescope of Abastumani Observatory starting on Jan. 27 (UT) 15:09:06.
We obtained several 60 s exposures in R-filter. We do not detect any
source within Swift-XRT position (Moss et al., GCN 26895).
Preliminary photometry of the field is following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2020-01-27 15:09:06 0.02922 R 35*60 n/d n/d 20.4
Photometry is based on nearby USNO-B1.0 stars (R2 magnitude):
USNO-B1.0_id R2
1349-0340354 14.16
1349-0343444 15.86
GCN Circular 26901
Subject
GRB 200127A: Swift-XRT refined Analysis
Date
2020-01-27T23:51:22Z (5 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) , B. Sbarufatti (PSU),
D.N. Burrows (PSU) and M.J. Moss report on behalf of the Swift-XRT
team:
We have analysed 8.3 ks of XRT data for GRB 200127A (Moss et al. GCN
Circ. 26895), from 130 s to 18.2 ks after the BAT trigger. The data
comprise 215 s in Windowed Timing (WT) mode (the first 9 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The refined XRT position is RA, Dec = 295.1933, +44.9008 which is
equivalent to:
RA (J2000): 19 40 46.40
Dec(J2000): +44 54 02.8
with an uncertainty of 3.5 arcsec (radius, 90% confidence).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=1.1 (+0.6, -2.6). At T+172 s the decay
steepens to an alpha of 2.58 (+0.18, -0.15) before breaking again at
T+648 s to a final decay with index alpha=1.32 (+0.09, -0.12).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.98 (+0.05, -0.04). The
best-fitting absorption column is consistent with the Galactic value
of 2.2 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.75 (+0.12, -0.11) and a best-fitting absorption
column consistent with the Galactic value. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 4.1 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.2 (+0.3, -0.0) x 10^21 cm^-2
Galactic foreground: 2.2 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.75 (+0.12, -0.11)
If the light curve continues to decay with a power-law decay index of
1.32, the count rate at T+24 hours will be 1.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.6 x
10^-14 (9.4 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00952791.
This circular is an official product of the Swift-XRT team.
GCN Circular 26902
Subject
GRB 200127A: Enhanced Swift-XRT position
Date
2020-01-28T00:01:49Z (5 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 7439 s of XRT Photon Counting mode data and 12 UVOT
images for GRB 200127A, 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 = 295.19300, +44.90029 which is equivalent
to:
RA (J2000): 19h 40m 46.32s
Dec (J2000): +44d 54' 01.0"
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 26904
Subject
GRB 200127A: Nanshan-0.6m optical upper limit
Date
2020-01-28T02:37:47Z (5 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
X. Liu, D. Xu, Z.P. Zhu, B.Y. Yu, Y. Ma (NAOC), X. Gao (Urumqi No.1
Senior High School) report:
We observed the field of GRB 200127A (Moss et al., GCN 26895) using the
NEXT-0.6m telescope located at Nanshan, Xinjiang, China. Observations
started at 23:26:58 UT on 2020-01-27 (i.e., 8.71 h after the BAT
trigger), and 7x300 s Sloan r-band frames were obtained.
No optical afterglow is detected within the enhanced Swift-XRT error
circle (Evans et al., GCN 26902) in our stacked image, down to a
limiting magnitude of r ~ 20.5, calibrated with the nearby PanSTARRS field.
GCN Circular 26913
Subject
GRB200127A: Nordic Optical telecope optical upper limit
Date
2020-01-28T10:21:58Z (5 years ago)
From
Johan Fynbo at Neils Bohr Institute <jfynbo@nbi.ku.dk>
Johan P. U. Fynbo (DAWN/NBI), Daniele B. Malesani (DTU Space), Kasper E. Heintz (Univ. Iceland), Luca Izzo (DARK/NBI), Amanda Djupvik (NOT), report on behalf of a larger collaboration:
On 2020 Jan 28.292 UT (16.274 hr after the GRB) we observed the field of GRB200127A (Moss et al., GCN 26895; Evans et al., GCN26902) with the Nordic Optical Telescope in the SDSS r-filter for a total integration time of 900 s. Within the XRT position, we find no evidence for afterglow emission above a 3-sigma limit of about 23 mag AB, calibrated against field stars from the PAN-STARRS catalog.
GCN Circular 26914
Subject
GRB 200127A: Mondy optical upper limit
Date
2020-01-28T10:35:13Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), E. Mazaeva (IKI),
A. Volnova (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 200127A (Moss et al., GCN 26895) with
AZT-33IK telescope of Sayan observatory (Mondy) starting on Jan. 27
(UT) 21:48:01. We do not detect any optical object within Enhanced
Swift-XRT position (Evans et al., GCN 26902) in agreement with
non-detection of an afterglow (Liu et al., GCN 26904; Fynbo et al., GCN
26913). Preliminary photometry of the field is following.
Date UT start t-T0, Filter Exp., OT Err UL(3sigma)
(days) (s)
2020-01-27 21:48:01 0.30868 R 21*120 n/d n/d 22.8
Photometry is based on the USNO-B1.0 nearby stars.
USNO-B1.0 R2
1349-0340555 18.02
1349-0340544 17.39
GCN Circular 26919
Subject
GRB 200127A: Swift/UVOT Upper Limits
Date
2020-01-28T19:11:13Z (5 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
A. Belles (PSU) and M. J. Moss (GWU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200127A
150 s after the BAT trigger (Moss et al., GCN Circ. 26895).
No optical afterglow consistent with the XRT position (Evans et al.,
GCN Circ. 26902) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 150 300 147 >20.4
u_FC 310 560 246 >19.4
white 150 11742 1368 >22.3
v 640 16568 1317 >20.2
b 566 10830 1121 >21.3
u 310 6701 638 >20.2
w1 690 18173 1095 >21.1
m2 838 17473 1298 >20.6
w2 615 12437 1110 >20.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.16 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 26939
Subject
GRB 200127A: Swift-BAT refined analysis
Date
2020-01-29T22:48:04Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
D. M. Palmer (LANL), 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), M. J. Moss (GWU)
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+1079 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 200127A (trigger #952791)
(Moss et al., GCN Circ. 26895). The BAT ground-calculated position is
RA, Dec = 295.206, 44.934 deg which is
RA(J2000) = 19h 40m 49.4s
Dec(J2000) = +44d 56' 03.5"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.
The mask-weighted light curve shows a long weak emission that starts
around ~T-150 s and ends at ~T+90 s. T90 (15-350 keV) is 216.9 +- 23.5 sec
(estimated error including systematics).
The time-averaged spectrum from T-144.22 to T+92.97 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
1.64 +- 0.19. The fluence in the 15-150 keV band is 2.4 +- 0.3 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+41.80 sec in the 15-150 keV band
is 0.7 +- 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/952791/BA/