GRB 141017A
GCN Circular 17028
Subject
GRB 141017A: Skynet PROMPT-CTIO/SSO Observations
Date
2014-11-05T15:40:00Z (11 years ago)
From
Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet <atrotter@physics.unc.edu>
A. Trotter, J. Haislip, D. Reichart, A. Aji, R. Beauchemin, T. Berger,
A. Dow, A. Foster, N. Frank, M. Hinckle, K. Ivarsen, A. LaCluyze, M.
Maples, J. Moore, M. Nysewander, C. Salemi, L. Zbinden, and J. A. Crain
report:
Skynet observed the Swift XRT localization of GRB 141017A (Marshall et
al., GCN 16919, Swift trigger=615672) with one 24" telescope (P-CTIO 8;
I band) and three 16" telescopes (P-CTIO 1,4,5; V,R,I bands) of the
PROMPT array at CTIO, Chile, and with one 16" telescope (P-SSO 3; R
band) of the PROMPT array at Siding Spring Observatory, Australia.
Starting at 2014-10-18 01:10 UT and continuing until 2014-10-20 02:26 UT
(t=6.7h-2.3d post-trigger), Skynet took a total of 2316 exposures
ranging from 80s-160s each. We stacked subsets of these images to
maximize the S/N ratio, and detected no optical source in any band at
the OT position reported by Swift UVOT (Oates & Marshall, GCN 16924) and
confirmed by GROND (Kann, Guelbenzu & Greiner, GCN 16926). Our 3-sigma
limiting magnitudes are:
==================================
tmid scope expos fil limit
==================================
7.4h P-CTIO4 26x160s R >21.1
11.2h P-CTIO8 260x80s I >22.2
11.2h P-CTIO1 147x160s V >22.6
11.3h P-CTIO5 143x160s I >22.0
20.8h P-SSO3 134x160s R >22.3
36.5h P-CTIO1 40x160s V >22.0
37.2h P-CTIO8 60x80s I >21.3
37.3h P-CTIO5 33x160s I >21.4
37.9h P-CTIO4 28x160s R >21.7
44.8h P-SSO3 133x160s R >22.4
2.3d P-CTIO1 30x160s V >21.4
2.3d P-CTIO5 30x160s I >20.7
2.3d P-CTIO8 53x80s I >20.5
2.3d P-CTIO4 22x160s R >21.1
==================================
Magnitudes are in the Vega System, calibrated to 5 APASS stars in the
field. Magnitudes have not been corrected for line-of-sight Milky Way
dust extinction, with expected E(B-V)=0.035 (Schlafly & Finkbeiner 2011).
No further Skynet observations are scheduled.
GCN Circular 16929
Subject
Konus-Wind observation of GRB 141017A
Date
2014-10-20T10:22:18Z (11 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lyssenko, and T. Cline
on behalf of the Konus-Wind team, report:
A long-duration GRB 141017A (Swift-BAT trigger 615672:
Marshall et al., GCN 16919; Markwardt et al., GCN 16927)
triggered Konus-Wind at T0=66374.721 s UT (18:26:14.721),
or ~46 s after the BAT trigger.
The KW light curve shows two episodes of the emission.
The first, weaker episode, which triggered BAT, starts at ~T0-47 s
and ends at ~T0-42 s. The second, much more brighter episode,
which triggered KW, shows a double-peaked pulse from ~T0-3 s to ~T0+7 s.
The emission in this episode is visible up to ~1 MeV.
As observed by Konus-Wind, the burst had a fluence
of 4.0(-0.5,+0.5)x10^-6 erg/cm2, and a 64-ms peak flux,
measured from T0+0.704 s, of 1.8(-0.2,+0.2)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the second episode
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 1.5 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -0.89(-0.28,+0.31),
and the peak energy Ep = 97(-10,+12) keV,
chi2 = 73/60 dof.
Fitting this spectrum with the Band model yields the same
values of alpha and Ep and an upper limit on beta of -3.0
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB141017_T66374/
All the quoted errors are at the 95% confidence level.
All the quoted values are preliminary.
GCN Circular 16927
Subject
GRB 141017A, Swift-BAT refined analysis
Date
2014-10-19T14:15:17Z (11 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
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-240 to T+700 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 141017A (trigger #615672)
(Marshall, et al., GCN Circ. 16919). The BAT ground-calculated position is
RA, Dec = 93.601, -58.596 deg which is
RA(J2000) = 06h 14m 24.2s
Dec(J2000) = -58d 35' 45.9"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.
The mask-weighted light curve shows a double-peaked structure.
The first peak starts at ~T-1 s, peaks at ~T+1 s, and ends at ~T+3s.
The second peak starts at ~T+40s, peaks at ~T+46s, and ends at ~T+60s.
T90 (15-350 keV) is 55.7 +- 2.8 sec (estimated error including systematics).
The time-averaged spectrum from T-1.2 to T+65.1 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.05 +- 0.28,
and Epeak of 80.4 +- 17.2 keV (chi squared 39.44 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 3.1 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+46.60 sec in the 15-150 keV band is
6.7 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.66 +- 0.06 (chi squared 55.80 for 57 d.o.f.). 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/615672/BA/
GCN Circular 16926
Subject
GRB 141017A: GROND Afterglow Confirmation
Date
2014-10-19T12:57:11Z (11 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, A. Nicuesa Guelbenzu (both TLS Tautenburg), and J. Greiner
(MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 141017A (Swift trigger 615672; Marshall et
al., GCN #16919) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at La Silla
Observatory (Chile).
Observations started at 02:50 UT on 18 October 2014, around 8.5 hours
after the GRB trigger. They were performed at an average seeing of 1".7
and at an average airmass of 1.9.
Based on images with exposure times of 4130 s in g'r'i'z' (centered 0.459
days after the GRB) and 4800 s in JHK (centered 0.426 days after the GRB),
we detect a source within the Swift-XRT error circle reported by Goad et
al. (GCN #16921) at position
RA (J2000) = 06:14:31.28
Dec. (J2000) = -58:34:56.5
with an error of 0".5 and the following 3-sigma AB magnitudes:
g' = 24.3 +/- 0.2 mag,
r' = 23.6 +/- 0.2 mag,
i' = 23.4 +/- 0.2 mag,
z' = 23.2 +/- 0.3 mag,
J > 22.0 mag,
H > 21.4 mag, and
K > 20.3 mag.
The object has faded strongly compared to the early UVOT detection (Oates
et al., GCN #16924) and the Zadko Gingin detection (Klotz et al., GCN
#16920), confirming it as the afterglow. At this time, we cannot conclude
if this object might already be the host galaxy of GRB 141017A. Comparison
with an epoch taken 75 minutes earlier at lower S/N shows no significant
evidence for fading, but the spectrum is well-described by a spectral
slope with beta = 1 and a possible drop-out in g' (redshift z > 2.2).
Given magnitudes are derived based on calibrating the images against GROND
zeropoints (g'r'i'z') and 2MASS field stars (JHK) and are not corrected
for the Galactic foreground extinction corresponding to a reddening of
E_(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).
GCN Circular 16924
Subject
GRB 141017A: Swift/UVOT Detection
Date
2014-10-18T11:06:06Z (11 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (IAA-CSIC/UCL-MSSL) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 141017A
92 s after the BAT trigger (Marshall et al., GCN Circ. 16919).
A source consistent with the XRT position (Goad et al. GCN Circ. 16921)
is detected in the initial UVOT white filter exposures.
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) 92 242 150 20.54 +/- 0.25
white 859 1009 159 >20.91
v 633 13060 691 >20.0
b 559 17991 1306 >21.4
u 304 7171 717 >20.7
w1 683 6966 471 >20.3
m2 5133 6761 388 >20.1
w2 6152 12850 1082 >21.1
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 16922
Subject
GRB 141017A: Swift-XRT refined Analysis
Date
2014-10-18T06:50:05Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
K.L. Page (U. Leicester), C. Pagani (U. Leicester), A. Melandri
(INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), P. D'Avanzo (INAF-OAB), J.A.
Kennea (PSU), V. Mangano (PSU), M.C. Stroh (PSU), A.P. Beardmore (U.
Leicester) and F.E. Marshall report on behalf of the Swift-XRT team:
We have analysed 7.7 ks of XRT data for GRB 141017A (Marshall et al.
GCN Circ. 16919), from 77 s to 18.8 ks after the BAT trigger. The
data comprise 120 s in Windowed Timing (WT) mode (the first 6 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. 16921).
The late-time light curve (from T0+4.9 ks) can be modelled with a
power-law decay with a decay index of alpha=0.82 (+/-0.12).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.45 (+0.15, -0.14). The
best-fitting absorption column is 2.1 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 3.8 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.02 (+/-0.11) and a
best-fitting absorption column of 1.9 (+0.4, -0.3) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.5 x 10^-11 (4.7 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.9 (+0.4, -0.3) x 10^21 cm^-2
Galactic foreground: 3.8 x 10^20 cm^-2
Excess significance: 7.2 sigma
Photon index: 2.02 (+/-0.11)
If the light curve continues to decay with a power-law decay index of
0.82, the count rate at T+24 hours will be 0.034 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-12 (1.6 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00615672.
This circular is an official product of the Swift-XRT team.
GCN Circular 16921
Subject
GRB 141017A: Enhanced Swift-XRT position
Date
2014-10-17T23:29:03Z (11 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 3763 s of XRT Photon Counting mode data and 7 UVOT
images for GRB 141017A, 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 = 93.62994, -58.58229 which is equivalent
to:
RA (J2000): 06h 14m 31.19s
Dec (J2000): -58d 34' 56.2"
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 16920
Subject
GRB 141017A: Zadko observatory - Gingin optical observations
Date
2014-10-17T20:32:44Z (11 years ago)
From
Alain Klotz at IRAP-CNRS-OMP <Alain.Klotz@free.fr>
A. Klotz, D. Turpin (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR),
D. Coward (UWA),
M. Boer, B. Gendre, K. Siellez, H. Dereli, O. Bardho (UNS-CNRS-OCA),
A. Williams (PO-UWA), R. Martin (PO-UWA)
report:
We imaged the field of GRB 141017A detected by SWIFT
(trigger 615672) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.
The observations started 42 min after the GRB trigger.
The elevation of the field increased from
58 degrees above horizon and weather conditions
were excellent.
We examined a series of exposures obtained between
42 min and 110 min. In the error box given by SWIFT XRT
(Marshall et al. GCNC 16919) we detect a source of
magnitude R=22.4 (+/-0.4) which does not seem to be variable.
Its position is 06:14:31.2 -58:34:56 J2000.0.
We do not believe that it is the afterglow of GRB 141017A.
We conclude the afterglow of GRB 141017A is fainter
than R=22.4 42 minutes after the trigger.
Magnitudes were estimated with the nearby NOMAD1 stars
and are not corrected for galactic dust extinction.
GCN Circular 16919
Subject
GRB 141017A: Swift detection of a burst
Date
2014-10-17T18:50:12Z (11 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC),
H. A. Krimm (CRESST/GSFC/USRA), A. Y. Lien (GSFC/UMBC),
V. Mangano (PSU), K. L. Page (U Leicester),
B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU) and
E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team:
At 18:25:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 141017A (trigger=615672). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 93.629, -58.554 which is
RA(J2000) = 06h 14m 31s
Dec(J2000) = -58d 33' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows two main peaks
with a duration of about 60 sec. The peak count rate
was ~6000 counts/sec (15-350 keV), at ~50 sec after the trigger.
The XRT began observing the field at 18:26:52.0 UT, 84.0 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 93.6284, -58.5836 which is equivalent to:
RA(J2000) = +06h 14m 30.82s
Dec(J2000) = -58d 35' 01.0"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 106 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 4.83e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 91 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 19.6 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 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.04.
Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.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.)