GRB 141020A
GCN Circular 16976
Subject
GRB 141020A: Continued Mondy Observations, optical upper limit
Date
2014-10-29T00:06:16Z (12 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), M. Eselevich
(ISTP), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We observed the field of the Swift GRB 141020A (Cenko et al., GCN
16928) with with AZT-33IK telescope of Sayan observatory (Mondy). We
obtained several images on Oct. 23 starting on (UT) 14:25:05. At the
position of optical afterglow (Cenko et al., GCN 16928; Kuin et al., GCN
16932; Mazaeva et al., GCN 16943) we do not detect any object down to
R=23.0. Preliminary photometry is following:
date UT start t-T0 Filter Exp. OT OT_UL (3 sigma)
(mid, days) (s)
2014-10-23 14:25:05 3.3309 R 80*120 n/d 23.0
The photometry is based on SDSS stars reported in GCN 16943.
GCN Circular 16948
Subject
GRB 141020A: AAO optical upper limit
Date
2014-10-25T00:48:28Z (12 years ago)
From
Alexei Pozanenko at IKI <alex@grb.rssi.ru>
E. Mazaeva (IKI), R. Inasaridze (AAO), A. Volnova (IKI), Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 141020A (Cenko et al., GCN 16928) with AS-32 (0.7m) telescope of Abastumani Observatory. We obtained several unfiltered images on Oct. 20 starting on (UT) 15:41:01. At the position reported in (Kuin et al., GCN 16932) we do not detect the afterglow of GRB 141020A (Cenko et al., GCN 16928; Kuin et al., GCN 16932; Mazaeva et al., GCN 16943). Preliminary photometry is following:
date UT start t-T0 Filter Exp. OT UL(3sigma)
(mid, days) (s)
2014-10-20 15:41:01 0.3630 clear 38*120 n/d 21.4
The photometry is based on SDSS stars reported in GCN 16943.
GCN Circular 16947
Subject
GRB 141020A: Khureltogot optical upper limit
Date
2014-10-25T00:46:27Z (12 years ago)
From
Alexei Pozanenko at IKI <alex@grb.rssi.ru>
E. Mazaeva (IKI), S. Schmalz (AIP), N. Tungalag (Research Center of Astronomy and Geophysics MAS), A. Volnova (IKI), I.Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 141020A (Cenko et al., GCN 16928) with ORI-40 telescope of Khureltogot observatory. We obtained several unfiltered images on Oct. 20 starting on (UT) 12:09:56. At the position reported in (Kuin et al., GCN 16932) we do not detect the afterglow of GRB 141020A (Cenko et al., GCN 16928; Kuin et al., GCN 16932; Mazaeva et al., GCN 16943). Preliminary photometry is following:
date UT start t-T0 Filter Exp. OT UL(3sigma)
(mid, days) (s)
2014-10-20 12:09:56 0.2037 clear 60*60 n/d 19.8
The photometry is based on SDSS stars reported in GCN 16943.
GCN Circular 16943
Subject
GRB 141020A: Mondy optical observations
Date
2014-10-22T18:36:37Z (12 years ago)
From
Alexei Pozanenko at IKI <alex@grb.rssi.ru>
E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), M. Eselevich (ISTP), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 141020A (Cenko et al., GCN 16928) with with AZT-33IK telescope of Sayan observatory (Mondy). We obtained several images on Oct. 20 starting on (UT) 13:28:20. At the position reported in (Kuin et al., GCN 16932) we clearly detect the afterglow of GRB 141020A (Cenko et al., GCN 16928; Kuin et al., GCN 16932). Preliminary photometry is following:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-10-20 13:28:20 10.2672 R 45*120 22.0 0.3
The photometry is based on SDSS stars
SDSS R_Lupton
J150002.80+552112.7 16.749
J150012.34+552137.2 17.210
J150017.07+551830.3 18.482
J150000.59+552221.9 17.001
The finding chart can be found in
http://grb.rssi.ru/GRB141020A/GRB141020A_R_AZT33IK_fc.png
GCN Circular 16935
Subject
GRB 141020A: Swift-BAT refined analysis
Date
2014-10-20T21:06:53Z (12 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
S. B. Cenko (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 141020A (trigger #615873)
(Cenko, et al., GCN Circ. 16928). The BAT ground-calculated position is
RA, Dec = 225.054, 55.328 deg which is
RA(J2000) = 15h 00m 12.9s
Dec(J2000) = +55d 19' 42.3"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 67%.
The mask-weighted light curve shows a broad structure with multiple peaks
superimposed starting at T-8 sec and continuing until T+13 sec. T90 (15-350
keV) is 15.55 +- 2.05 sec (estimated error including systematics).
The time-averaged spectrum from T-5.66 to T+11.30 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.74 +- 0.18. The fluence in the 15-150 keV band is 4.6 +- 0.6 x 10^-7
erg/cm2. The 1-sec peak photon flux measured from T-0.20 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/615873/BA/
GCN Circular 16934
Subject
GRB 141020A: Swift-XRT refined Analysis
Date
2014-10-20T20:01:05Z (12 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
C. Pagani (U. Leicester), B. Sbarufatti (INAF-OAB/PSU), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), V. Mangano (PSU), M.C. Stroh (PSU), D.N.
Burrows (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester)
and S.B. Cenko report on behalf of the Swift-XRT team:
We have analysed 9.8 ks of XRT data for GRB 141020A (Cenko et al. GCN
Circ. 16928), from 72 s to 23.9 ks after the BAT trigger. The data
comprise 6 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Osborne et al. (GCN Circ.
16931).
The late-time light curve (from T0+4.8 ks) can be modelled with a
power-law decay with a decay index of alpha=1.10 (+0.24, -0.22).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.80 (+0.16, -0.13). The
best-fitting absorption column is 2.3 (+3.6, -1.0) x 10^20 cm^-2,
consistent with the Galactic value of 1.2 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 3.5 x 10^-11 (3.7 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.3 (+3.6, -1.0) x 10^20 cm^-2
Galactic foreground: 1.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.80 (+0.16, -0.13)
If the light curve continues to decay with a power-law decay index of
1.10, the count rate at T+24 hours will be 3.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (1.1 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/00615873.
This circular is an official product of the Swift-XRT team.
GCN Circular 16933
Subject
GRB 141020A: 1.4 GHZ observation
Date
2014-10-20T17:19:46Z (12 years ago)
From
Dirk Grupe at Swift-XRT <dgrupe007@gmail.com>
D. Grupe and B. Malphrus (Space Science Center, Morehead State
University) report:
We observed the UVOT position of GRB 141020A (Cenko et al., GCN
Circ. 16928) with the 21m Morehead State University 21m Space
Tracking Antenna at 1.4 GHz at 2014-10-20 13:20 UT, 5.5 hours after
the burst. We did not detect any source at the position of the
burst. The minimal detactable flux density of the MSU 21m telescope
is 2 Jy.
GCN Circular 16932
Subject
GRB 141020A: Swift/UVOT Detection
Date
2014-10-20T15:59:40Z (12 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N.P. M. Kuin (UCL-MSSL) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 141020A
92 s after the BAT trigger (Cenko et al., GCN Circ. 16928). A source
consistent with the XRT position (Osborne et al. GCN Circ. 16931)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 14:59:59.15 = 224.99646 (deg.)
Dec (J2000) = +55:18:46.7 = 55.31297 (deg.)
with an estimated uncertainty of 0.43 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 92 241 147 18.02 +/- 0.04
v 634 1409 58 18.40 +/- 0.23
b 559 753 39 18.66 +/- 0.18
u 304 554 246 18.48 +/- 0.09
w1 683 6660 471 >20.9
m2 1238 6455 413 >21.1
w2 784 11546 1196 >21.8
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 16931
Subject
GRB 141020A: Enhanced Swift-XRT position
Date
2014-10-20T14:13:36Z (12 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 2694 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 141020A, 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 = 224.99618, +55.31341 which is equivalent
to:
RA (J2000): 14h 59m 59.08s
Dec (J2000): +55d 18' 48.3"
with an uncertainty of 1.6 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 16928
Subject
GRB 141020A: Swift detection of a burst with an optical counterpart
Date
2014-10-20T08:01:15Z (12 years ago)
From
Hans Krimm at NASA-GSFC <hans.krimm@nasa.gov>
S. B. Cenko (GSFC), A. P. Beardmore (U Leicester),
M. M. Chester (PSU), H. A. Krimm (CRESST/GSFC/USRA),
P. T. O'Brien (U Leicester) and K. L. Page (U Leicester) report on
behalf of the Swift Team:
At 07:48:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 141020A (trigger=615873). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 225.009, +55.334 which is
RA(J2000) = 15h 00m 02s
Dec(J2000) = +55d 20' 02"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a complex
structure with a duration of about 30 sec. The peak count rate
was ~1700 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 07:50:06.5 UT, 87.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 224.99514, 55.31391 which is equivalent
to:
RA(J2000) = 14h 59m 58.83s
Dec(J2000) = +55d 18' 50.1"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 77 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 http://www.swift.ac.uk/sper. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.25
x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 91 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 14:59:59.15 = 224.99647
DEC(J2000) = +55:18:46.8 = 55.31299
with a 90%-confidence error radius of about 0.75 arc sec. This position is 4.2
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.73 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.01.
Burst Advocate for this burst is S. B. Cenko (brad.cenko 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/too.html.)