GRB 141026A
GCN Circular 16950
Subject
GRB 141026A: Swift detection of a burst
Date
2014-10-26T02:50:59Z (11 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
L. M. Z. Hagen (PSU), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU) and
M. H. Siegel (PSU) report on behalf of the Swift Team:
At 02:36:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 141026A (trigger=616502). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 44.080, +26.960 which is
RA(J2000) = 02h 56m 19s
Dec(J2000) = +26d 57' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The real-time TDRSS BAT light curve does not show
anything as is typical for an image trigger.
The XRT began observing the field at 02:39:28.2 UT, 157.0 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 44.0839, 26.9262 which is equivalent to:
RA(J2000) = +02h 56m 20.14s
Dec(J2000) = +26d 55' 34.3"
with an uncertainty of 6.1 arcseconds (radius, 90% containment). This
location is 122 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 0.1 s image was 1.58e-08 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 43 seconds with the White filter
starting 165 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
0.19.
Burst Advocate for this burst is L. M. Z. Hagen (lea.zernow.hagen 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/too.html.)
GCN Circular 16951
Subject
GRB 141026A: P60 early observations
Date
2014-10-26T04:07:01Z (11 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) reports on behalf of a larger collaboration:
The Palomar 60-inch telescope automatically responded to the alert for
GRB 141026A (Hagen et al, GCN 16950) and began imaging the field at
02:41:55.320 UT, 5.07 minutes after the Swift trigger. A sequence of
60-second r, i, and z exposures was obtained. The field was at high
airmass (~3.3) at the start of the observations.
We do not detect any clear source inside the XRT error circle in the
individual exposures. After stacking the first 11 frames taken in each
filter, in the r-band stack only there is a marginal detection of a
possible source at RA = 02:56:19.885, dec = +26:55:35.80 with R~22 mag.
Observations are continuing and additional follow-up is planned.
GCN Circular 16952
Subject
GRB 141026A: RATIR Optical Observations
Date
2014-10-26T05:47:05Z (11 years ago)
From
Owen Littlejohns at Az State U <olittlej@asu.edu>
Owen Littlejohns (ASU), Nat Butler (ASU), Antonino Cucchiara
(ORAU/GSFC), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein
(UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom
(UCB), Eleonora Troja (GSFC), Enrico Ramirez-Ruiz (UCSC),
Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s Gonz��lez
(UNAM), Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:
We observed the field of GRB 141026A (Hagen, et al., GCN 16950)
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
26.13 to 26.20 UTC (0.54 to 2.20 hours after the BAT trigger),
obtaining a total of 1.07 hours exposure in the r and i bands.
For a source within the Swift-XRT error circle, we obtain the
following upper limits (3-sigma):
r > 23.50
i > 23.56
These magnitudes are in the AB system and are not corrected for
Galactic extinction in the direction of the GRB.
We do not detect the source observed by P60 (Perley, et al., GCN
16951). We do, however, detect a source at the edge of the Swift-
XRT error circle at RA(J2000) = 44.084036, Dec(J2000) = 26.928134.
r 21.67 +/- 0.08
i 21.52 +/- 0.07
We cannot presently determine if this source is fading.
We thank the staff of the Observatorio Astron��mico Nacional in San
Pedro M��rtir.
GCN Circular 16953
Subject
GRB 141026A: GROND observations
Date
2014-10-26T05:56:23Z (11 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
K. Varela (MPE Garching), D. A. Kann (TLS Tautenburg), and J. Greiner (MPE
Garching) report on behalf of the GROND team:
We observed the field of GRB 141026A (Swift trigger 616502; Hagen et al.,
GCN #16950) 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 ESO La Silla
Observatory (Chile).
Observations started at 02:51 UT on October 26th, approximately 15 min
after the GRB trigger. They were performed at high airmass (2.5 but
rising) but decent seeing (1".2).
At the position of the P60 candidate (Perley, GCN #16951) we do not detect
any source. We find a source just to the north of the 5".8 Swift-XRT error
circle reported by Hagen et al. at
RA (J2000.0) = 02:56:20.16
DEC (J2000.0) = +26:55:41.4
with an error of 0".5. This source is also reported by RATIR (Littlejohns
et al., GCN #16952). We do not find any variability within errors over the
course of our observations. It is likely not associated with the GRB.
Based on images with an exposure time of 1500 s in the optical and 1200 s
in the NIR, centered at 0.05598 days after the trigger, we estimate
preliminary magnitudes and limits (all in AB system) for this source of:
g' = 23.2 +/- 0.1 mag
r' = 21.8 +/- 0.1 mag
i' = 21.5 +/- 0.1 mag
z' = 21.2 +/- 0.1 mag
J = 20.9 +/- 0.3 mag
H = 20.5 +/- 0.3 mag
K > 18.7 mag
Given magnitudes are calibrated against GROND zeropoints (g'r'i'z') and
2MASS field stars (JHK) and are not corrected for the expected Galactic
foreground extinction corresponding to a reddening of E_(B-V)=0.18 mag in
the direction of the burst (Schlegel et al. 1998).
GCN Circular 16954
Subject
GRB 141026A: 1.23m CAHA I-band observations
Date
2014-10-26T06:22:36Z (11 years ago)
From
Javier Gorosabel at IAA-CSIC <jgu@iaa.es>
J. Gorosabel (IAA-CSIC/UPV-EHU), S. Hellmich (DLR), A. de Ugarte Postigo
(IAA-CSIC/DARK), S. Mottola (DLR), report on behalf of a larger
collaboration:
We observed the field of the GRB141026A (Hagen, et al., GCN 16950) with
the 1.23m CAHA telescope in the I-band filter. Observations started on
Oct. 26.11639 UT (10.75 min post burst). A faint object is detected at
RA=02:56:20.13, DEC=26:55:41.3 (+/-0.6", J2000) with Vega magnitude I~20.6
against the USNO B1.0 catalog. The coordinates of this object are
consistent with the ones reported by Littlejohns et al. (GCN 16592) and
Varela et al. (GCN 16953). No object brighter than I~21.0 (Vega) is
detected consistent with the optical source reported by Perley (GCN
16951).
GCN Circular 16955
Subject
GRB141026A: Deep P200 optical imaging
Date
2014-10-26T07:51:45Z (11 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley, M. Brown, I. Wong, and E. Bailey (Caltech) report:
We imaged the location of GRB 141026A (Hagen et al., GCN 16950) using
the Large-Format Camera on the 5m Hale Telescope at Palomar Observatory.
Six exposures of four minutes each were acquired using the Broad-RI
(620-920 nm) filter between 03:34:50 and 04:03:51 UT (58-87 minutes
after the BAT trigger).
The object north of the error circle reported by Littlejohns et al. (GCN
16592), Varela et al. (GCN 16953), and Gorosabel et. al (GCN 16954) is
well-detected in the stacked image. No other object is detected in or
near the XRT error circle, including at the position of the
previously-reported, low-significance object from the early P60 imaging
(GCN 16951), down to a limit of RI > 25.5 mag (calibrated relative to
the R2 magnitude of a nearby USNO B1.0 star).
GCN Circular 16956
Subject
GRB 141026A: Enhanced Swift-XRT position
Date
2014-10-26T12:06:07Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 2855 s of XRT Photon Counting mode data and 8 UVOT
images for GRB 141026A, 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 = 44.08435, +26.92804 which is equivalent
to:
RA (J2000): 02h 56m 20.24s
Dec (J2000): +26d 55' 40.9"
with an uncertainty of 1.9 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 16957
Subject
GRB 141026A: MASTER early optical observations
Date
2014-10-26T12:24:38Z (11 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <gcncirc@observ.inetcomm.ru>
E. Gorbovskoy, V. Lipunov, M.Pruzhinskaya, V.Kornilov, D.Kuvshinov, N.Tyurina,
P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Denisenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik
Kislovodsk Solar Station of the Pulkovo Observatory
V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov, A. Gabovich
Blagoveschensk Educational State University, Blagoveschensk
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University
V.Krushinski, I.Zalozhnih, A. Popov
Ural Federal University, Kourovka
Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in
Kislovodsk was pointed to the GRB141026A 22 sec after notice time and 99 sec
after trigger time at 2014-10-26 02:38:31 UT in two polarizations. On our first
single and coadd images we haven`t found optical transient within SWIFT
error-box (Hagen et. al. GCN 16950). The 5-sigma upper limit has been about
16.5 on single (20s exposure) and 17.5 on coadd image (from first 3 images with
total exposure 80 sec). The message may be cited.
The publication delay was due to time zone changes during this night.
This message may be cited.
GCN Circular 16960
Subject
GRB 141026A: Swift-BAT refined analysis
Date
2014-10-26T14:41:51Z (11 years ago)
From
Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), L. M. Z. Hagen (PSU),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), J. Tueller (GSFC), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+380 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 141026A (trigger #616502)
(Hagen, et al., GCN Circ. 16950). The BAT ground-calculated position is
RA, Dec = 44.049, 26.925 deg which is
RA(J2000) = 02h 56m 11.8s
Dec(J2000) = +26d 55' 31.7"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 88%.
The mask-weighted light curve shows a weak episode starting at ~T+15 sec,
and ending around ~T+180 sec. T90 (15-350 keV) is 146 +- 13 sec (estimated
error including systematics). Note since this GRB went outside the FOV of
BAT around ~T+250 sec, this duration measurement might be affected if there
were significant emission from the source after ~T+250 sec.
The time-averaged spectrum from T+13.96 to T+177.75 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.34 +- 0.19. The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+65.64 sec in the 15-150 keV band
is 0.4 +- 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/616502/BA/
GCN Circular 16961
Subject
GRB 141026A: Swift-XRT refined Analysis
Date
2014-10-26T17:51:04Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA), D.N. Burrows (PSU),
J.A. Kennea (PSU), V. Mangano (PSU), P.A. Evans (U. Leicester), B.P.
Gompertz (U. Leicester), J.P. Osborne (U. Leicester), A. Maselli
(INAF-IASFPA) and L.M.Z. Hagen report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 141026A (Hagen et al. GCN
Circ. 16950), from 160 s to 46.2 ks after the BAT trigger. The data
comprise 49 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Beardmore et al. (GCN Circ. 16956).
The late-time light curve (from T0+3.5 ks) can be modelled with a
power-law decay with a decay index of alpha=0.35 (+0.11, -0.12).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.07 (+0.09, -0.08). The
best-fitting absorption column is 4.9 (+/-0.5) x 10^21 cm^-2, in
excess of the Galactic value of 1.6 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.92 (+0.28, -0.26)
and a best-fitting absorption column of 2.8 (+1.2, -1.0) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 3.8 x 10^-11 (5.4 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.8 (+1.2, -1.0) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^21 cm^-2
Excess significance: 2.0 sigma
Photon index: 1.92 (+0.28, -0.26)
If the light curve continues to decay with a power-law decay index of
0.35, the count rate at T+24 hours will be 0.023 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.9 x
10^-13 (1.2 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/00616502.
This circular is an official product of the Swift-XRT team.
GCN Circular 16962
Subject
GRB 141026A: Continued RATIR Optical and NIR Observations, Afterglow Detection
Date
2014-10-26T18:50:06Z (11 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), Chris Klein (UCB), Ori Fox (UCB),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:
We observed the field of GRB 141026A (Hagen, et al., GCN 16950)) 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 2014/10 26.13 to 2014/10 26.26 UTC (0.54 to
3.58 hours after the BAT trigger), obtaining a total of 2.49 hours exposure
in the r, i, and z bands.
With increased time-coverage, the source reported in Littlejohns et al.
(GCN 16952; also Perley et al., GCN 16955, Varela et al., GCN 16953,
Gorosabel et al., GCN 16954, ) appears to peak on a timescale of 1 hour,
and then fade in the r and i bands. Given also that its position is
consistent with the enhanched XRT error region (Beardmore et al., GCN
16956), this source is likely to be the afterglow to GRB 141026A. In
comparison with 2MASS, we obtain the following detections and upper limit
(3-sigma):
r 21.74 +/- 0.07
i 21.54 +/- 0.06
z > 20.5
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. Further observations are planned.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 16964
Subject
GRB 141026A: Swift/UVOT Upper Limits
Date
2014-10-26T21:57:26Z (11 years ago)
From
Lea Hagen at PSU <lea.zernow.hagen@gmail.com>
L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 141026A
166 s after the BAT trigger (Hagen et al., GCN Circ. 16950). No optical
afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 16956)
or the likely optical afterglow (Littlejohns et al. GCN Circ. 16952, Varela
et al. GCN Circ. 16953, Gorosabel et al. GCN Circ. 16954, Perley et al. GCN
Circ. 16955, Butler et al. GCN Circ. 16962) 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 initial exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (fc) 165 208 83 >19.98
white 3462 5667 688 >21.45
v 144 5962 290 >19.34
b 3826 5463 393 >20.48
u 3621 5258 393 >20.15
uvw1 4852 5052 196 >19.61
uvm2 4647 4847 196 >19.58
uvw2 4237 5873 393 >20.26
The magnitudes in the table are not corrected for the Galactic extinction
due to the substantial reddening of E(B-V) = 0.19 in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 16965
Subject
GRB 141026A: Continued RATIR Optical and NIR Observations
Date
2014-10-27T16:56:57Z (11 years ago)
From
Nat Butler at Az State U <natbutler@asu.edu>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:
We observed the field of GRB 141026A (Hagen, et al., GCN 16950)) 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 2014/10 27.13 to 2014/10 27.53 UTC (24.48 to
34.08 hours after the BAT trigger), obtaining a total of 4.64 hours
exposure in the r, i, and z bands.
The optical afterlow (Littlejohns et al., GCN 16952; also Perley et al.,
GCN 16955, Varela et al., GCN 16953, Gorosabel et al., GCN 16954, Butler,
et al., GCN 16962) continues to fade. In comparison with 2MASS, we obtain
the following detections and upper limit (3-sigma):
r 22.94 +/- 0.16
i 23.16 +/- 0.22
z > 20.1
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. The source appears to have faded
roughly as t^(-0.5) since our last epoch (GCN 16962).
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir. Further observations are planned.
GCN Circular 16966
Subject
GRB 141026A: SAO RAS Zeiss-1000 observations
Date
2014-10-27T18:37:38Z (11 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
A. S. Moskvitin, V. N. Komarova, T. N. Sokolova (SAO RAS) report
on behalf of the GRB follow-up team:
We observed the field of GRB 141026A (Hagen et al., GCN 16950)
with the SAO RAS 1-m telescope Zeiss-1000 at the October 26/27 night.
The observations were started at 20:09:49 UT (in 17.55 hours
after the trigger), ended at 03:32:34. We obtained 61 x 300 sec.
images in the Rc filter.
The object mentioned by Littlejohns et al. (GCN 16592, GCN 16963),
Varela et al. (GCN 16953), Gorosabel et al. (GCN 16954),
Perley et al. (GCN 16955), Butler et al. (GCN 16962, GCN 16965)
is clearly detected in the stacked image.
The magnitude of OT is R = 22.1 +/- 0.1 (in Vega system, not corrected
for the Milky Way extinction). The photometry is based on the nearby
USNO-B1 stars.
[GCN OPS NOTE(27oct14): Per author's request, the name of the GRB
was corrected in the Subject-line: (13-->14).]
GCN Circular 16967
Subject
GRB 141026A: Skynet PROMPT-CTIO/Yerkes-41 Observations
Date
2014-10-27T20:26:34Z (11 years ago)
From
Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet <atrotter@physics.unc.edu>
A. Trotter, J. Haislip, D. Reichart, V. Hoette, K. Cudworth, D. Harper,
R. Kron, T. Linder, R. Russell, E. Struble, 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 BAT/XRT localization of GRB 141026A (Hagen et
al., GCN 16950, Swift trigger=616502) with one 24" telescope (PROMPT 8;
I band) and four 16" telescopes (PROMPT 3,1,4,5; BVRI bands) of the
PROMPT array at CTIO, Chile, and with the 41" telescope of Yerkes
Observatory in Wisconsin, USA (g'r'i' bands).
Starting at 2014-10-26 02:38:30 UT and continuing until 03:03 UT
(t=1.5-26m post-trigger), Skynet took a total of 89 exposures ranging
from 10s-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
first reported by RATIR (Littlejohns et al., GCN 16952), and confirmed
in later notices. Our 3-sigma limiting magnitudes are:
==================================
tmid scope expos fil limit
==================================
10m PROMPT3 4x80s B >19.9
20m PROMPT1 4x160s V >20.4
19m PROMPT4 3x160s R >19.8
17m PROMPT5 4x80s I >19.9
4X160s
17m PROMPT8 12x80s I >20.0
63m Yerkes 1x80s g' >21.2
2x160s
60m Yerkes 2x80s r' >20.9
1x160s
66m Yerkes 1x80s i' >20.5
1x160s
==================================
BVRI magnitudes are in the Vega System, and g'r'i' magnitudes are in the
AB system, calibrated to 4 APASS stars in the field. Magnitudes have
not been corrected for line-of-sight Milky Way dust extinction, with
expected E(B-V)=0.16 (Schlafly & Finkbeiner 2011).
No further Skynet observations are scheduled.
GCN Circular 16968
Subject
GRB 141026A: GTC spectroscopy
Date
2014-10-28T16:59:55Z (11 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CISC, DARK/NBI), C.C. Thoene (IAA-CSIC),
N.R. Tanvir (U. Leicester), J. Gorosabel (UPV, IAA-CSIC),
J. Fynbo (DARK/NBI), G. Lombardi (GTC), D. Reverte-Paya (GTC),
and D. Perez (GTC) report:
We observed the afterglow of GRB 141026A (Hagen et al. GCN 16950,
Perley GCN 16951, Littlejohns et al. GCN 16952, Varela et al. GCN 16953,
Gorosabel et al. GCN 16954, Perley et al. GCN 16955, Beardmore et al.
GCN 16956, Butler et al. GCN 16962,Moskvitin et al. GCN 16966) with
OSIRIS at the 10.4m Gran Telescopio Canarias. Observations consisted of
z-band imaging, and spectroscopy using the R1000R grism (covering from
5100 to 10000 A with a resolution of ~1000). The spectroscopic observations
were delayed due to bad weather and had a mean epoch of 6:12 UT (3.59
hours after the burst), and consisted of 2x900s exposures. Conditions were
not optimal, as the airmass at that time was ~1.8 and most of the observation
was performed during twilight.
The spectrum shows a low S/N continuum, which is however, visible
between 5100 and 9500 A. Some absorption features seem to be present,
and in particular we identify a broad feature at 5300 A, with an observed
equivalent width of ~30 A. This could correspond to a weak Ly-alpha
(log(N_H/cm^-2) ~< 20) absorption at z=3.35. However, no other features
corresponding to that same redshift are seen, which is not unexpected for
a low density line of sight that would correspond to such a Ly-alpha feature
and a low S/N spectrum. Further absorptions could correspond to intervening
MgII absorbers.
This redshift solution is supported by the photometric drop seen by GROND
in the g-band (Varela et al. GCN 16953), which would correspond to a similar
photometric redshift.
GCN Circular 16970
Subject
GRB 141026A: Continued RATIR Optical and NIR Observations
Date
2014-10-28T17:48:18Z (11 years ago)
From
Owen Littlejohns at Az State U <olittlej@asu.edu>
Owen Littlejohns (ASU), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer
(UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC),
Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja
(GSFC), Enrico Ramirez-Ruiz (UCSC), Jos�� A. de Diego (UNAM), Leonid
Georgiev (UNAM), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM),
Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We again observed the field of GRB 141026A (Hagen, et al., GCN 16950)
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 2014/10 28.13 to 2014/10
28.19 UTC (48.58 to 49.84 hours after the BAT trigger), obtaining a
total of 1.07 hours exposure in the r, i and z bands.
For a source within the Swift-XRT error circle, we obtain the
following upper limits (3-sigma):
r > 23.54
i > 23.31
z > 19.82
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. In comparison to previous epochs
of RATIR observations (Butler, et al., GCN 16965; Littlejohns, et al.,
GCN 16962), the GRB has continued to fade. The r band upper limit
indicates a power-law decay between this and the previous epoch of RATIR
observations with a minimum approximate index of t^(-0.9). This is
steeper than that reported in Butler, et al. (GCN 16965).
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 16974
Subject
GRB 141026A: IRAM 30m millimetre observations
Date
2014-10-28T20:26:53Z (11 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
A. J. Castro-Tirado, J. C. Tello, J. Gorosabel (IAA-CSIC Granada), C.
Kramer, I. Hermelo, G. Paubert, A. Sievers (IRAM Granada) and J. G.
Staguhn (NASA/GSFC Greenbelt),on behalf of a larger collaboration, report:
Following the detection of GRB 141026A by Swift (Hagen et al. GCNC
16950), observations with the IRAM 30m antenna (+GISMO) at Pico Veleta
(Spain) were triggered on 26-27 Oct. At the position of the optical
afterglow (Littlejohns et al. GCNC 16952, Varela et al. GCNC 16953,
Gorosabel et al. GCNC 16954), we detect no mm afterglow (at 2 mm) down to
a preliminary flux density of 1.2 mJy (3 sigma) on Oct 26, 14:30 UT (mid
time). We acknowledge excellent assistance from the IRAM observers.
GCN Circular 17019
Subject
GRB 141026A: VLA observations
Date
2014-11-02T15:39:26Z (11 years ago)
From
Alessandra Corsi at Texas Tech U <alessandra.corsi@ttu.edu>
A. Corsi (Texas Tech U.) reports on behalf of a larger collaboration:
We observed the location of GRB 141026A (Hagen et al., GCN 16950) with the
Karl G. Jansky Very Large Array (VLA) in its C configuration. Observations were
carried out in the frequency bands 18.7-24.9 GHz and 4.5-7.8 GHz. A provisional
reduction shows marginal detections at 21.8 GHz (at about 1.1 d and 4.3 d after the
burst), and a clearer detection at 6.2 GHz (at about 6 d after the burst), of a source
consistent with the location of the GRB optical afterglow (Littlejohns et al. GCN 16952;
Varela et al., GCN 16953; Gorosabel et al., GCN 16954; Perley et al. GCN 16955).
We estimate preliminary fluxes for this source of:
Mean epoch | Freq. (GHz) | Flux (uJy) | map rms (uJy)
------------------------------
6.5 hr | 21.8 | 11 | 11
------------------------------
1.1 d | 21.8 | 43 | 11
------------------------------
4.3 d | 21.8 | 31 | 8
------------------------------
6.0 d | 6.2 | 91 | 7
------------------------------
GCN Circular 17031
Subject
GRB 141026A: Gemini-North optical and NIR imaging
Date
2014-11-05T21:03:36Z (11 years ago)
From
Wen-fai Fong at U of Arizona <wfong@email.arizona.edu>
W. Fong (U. Arizona) and D. B. Fox (PSU) report on behalf of a larger
collaboration:
"We observed the location of the long-duration GRB 141026A (Hagen et al.,
GCN 16950) with the Gemini Multi-Object Spectrograph (GMOS) and the Near
InfraRed Imager (NIRI) mounted on the Gemini-North 8-m telescope starting
on 2014 Oct 26.402 UT (7.03 hr after the BAT trigger). We obtained 540-sec
of z-band imaging, and a total of 1800-sec in the YJHKs-bands. We clearly
detect the afterglow (Littlejohns et al., GCN 16952; Varela et al., GCN
16953; Gorosabel et al., GCN 16954; Perley et al., GCN 16955; Butler et
al., GCN 16962, GCN 16970; Moskvitin et al., GCN 16966) in all bands. Using
tabulated Gemini zeropoints, we measure an afterglow brightness of z(AB) =
22.0 +/- 0.1 mag and J(AB) = 21.9 +/- 0.1 mag at 7.03 hr after the burst.
These magnitudes have not been corrected for Galactic extinction in the
direction of the burst.
We thank the Gemini staff for their assistance with these observations."
GCN Circular 17033
Subject
GRB 141026A: CrAO optical observation
Date
2014-11-06T18:49:43Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev (CrAO), E. Mazaeva (IKI), A. Volnova (IKI), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
The GCN #17032 should be read as following:
(We are sorry for inconvenience)
We observed the field of the Swift GRB GRB 141026A (Hagen et al., GCN
16950) with ZTSh telescope of CrAO observatory starting on Oct. 26 (UT)
18:25:48. We took several images in R-filter of 120 s exposure under
poor weather conditions and mean seeing of 5". The optical afterglow
(Littlejohns et al. GCN 16592; Varela et al. GCN 16953; Gorosabel et al.
GCN 16954) is clearly visible in our stacked image. Photometry of a
combined image is following
Date UT start, t-t0 Filter Exp. OT OT_err
(mid, days) (s)
2014-10-26 18:25:48 0.7020 R 53*120 21.88 0.18
The photometry is based on USNO-B1.0 stars
RA DEC R
044,065509 +26,958050 18.71
044,051792 +26,894737 18.59
044,049131 +26,929059 17.48