GRB 141121A
GCN Circular 17075
Subject
GRB 141121A: Swift detection of a burst
Date
2014-11-21T04:07:51Z (11 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
A. Y. Lien (GSFC/UMBC), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (NASA/GSFC),
F. E. Marshall (NASA/GSFC), C. Pagani (U Leicester) and
D. M. Palmer (LANL) report on behalf of the Swift Team:
At 03:50:43 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 141121A (trigger=619182). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 122.668, +22.225 which is
RA(J2000) = 08h 10m 40s
Dec(J2000) = +22d 13' 31"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows no significant structure,
as usual for an image trigger.
The XRT began observing the field at 03:56:45.6 UT, 362.4 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 122.6700, 22.2177 which is equivalent to:
RA(J2000) = +08h 10m 40.80s
Dec(J2000) = +22d 13' 03.7"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 27 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 6.07e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 370 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
0.05.
Burst Advocate for this burst is A. Y. Lien (amy.y.lien 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.)
GCN Circular 17076
Subject
GRB141121A: BOOTES-2/TELMA upper limit
Date
2014-11-21T06:26:08Z (11 years ago)
From
Juan Carlos Tello at IAA-CSIC <jtello@iaa.es>
J. C. Tello (IAA-CSIC), J. Gorosabel (IAA-CSIC, UPV-EHU) and A, J.
Castro-Tirado (IAA-CSIC, ISA-UMA), on behalf of a larger collaboration,
report:
Following the detection of GRB 141121A by Swift (Lien et al., GCNC 17075),
the 0.6m TELMA robotic telescope at the BOOTES-2 astronomical station
Malaga (Spain), responded to the GRB location in poor weather conditions
(through clouds) starting at 04:01:57 UT (i.e. 11 min postburst). The
co-add of 10 images (i-band) starting at 04:06:03 UT and ending in 04:17:17
UT (i.e. 16-27min post burst) (60s integrations) provides an upper limit of
i > 16.5 for any object within the Swift/XRT error box. Further
observations are planned.
GCN Circular 17077
Subject
GRB 141121A: MAXI/GSC detection
Date
2014-11-21T06:31:44Z (11 years ago)
From
H. Negoro at Nihon U. <negoro@phys.cst.nihon-u.ac.jp>
F. Honda, K. Fukushima, H. Negoro (Nihon U.), N. Kawai (Tokyo Tech), S. Nakahira (JAXA),
M. Serino (RIKEN), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA),
T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN),
Y. Tachibana, T. Yoshii (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU),
H. Tsunemi, D. Uchida (Osaka U.),
M. Nakajima, T. Onodera, K. Suzuki, T. Namba, M. Fujita (Nihon U.),
Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, A. Kawagoe (Chuo U.),
M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.)
We report the MAXI/GSC detection of GRB 141121A (Li et al. GCN 17075).
The MAXI/GSC detected the source in the scan transit at 2014-11-21T03:44:47 (UT),
earlier than about 6 min before the BAT trigger.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (122.928 deg, 22.053 deg) = (08 11 42, +22 03 10) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.44 deg and 0.4 deg respectively.
The roll angle of long axis from the north direction is 174.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
This position is consistent with that reported as GRB 141121A.
The X-ray flux averaged over the scan was 57 +- 17 mCrab (4-10keV, 1 sigma error).
There was no significant excess flux in the previous transit at UT 00:39.
and in the next transit at 05:17 UT with an upper limit of 20 mCrab for each.
A simple power-law fit to the GSC spectrum gives a power-law index of 2.3 +/- 1.0.
These nature implies that the source is a long-GRB, or a new X-ray transient.
The followup observations are strongly encouraged to reveal the nature of the source.
GCN Circular 17078
Subject
GRB 141121A: GROND Afterglow candidate
Date
2014-11-21T07:15:06Z (11 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
M. Tanga (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 141121A (Swift trigger 619182; A. Y. Lien et
al., GCN 17075) 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 05:52 UT on November 21, 2014, 2.02 hours after
the GRB trigger. They were performed at an average seeing of 1".4 and at
an average airmass of 2.3.
Within the XRT error circle reported by Lien et al., we detect a bright
source in all bands. This source is not detected in the SDSS, therefore we
consider it to be the afterglow of GRB 141121A. The source lies at:
RA (J2000) = 08:10:40.62
Dec. (J2000) = +22:13:01.8
with an error of 0".3 in each coordinate.
Based on total exposures of 7.7 minutes in g'r'i'z' and 8.0 minutes in
JHK, at a midtime of 2.34 hrs after the burst, we measure the following
preliminary magnitudes (AB magnitude system):
g' = 20.0 +/- 0.1 mag,
r' = 19.8 +/- 0.1 mag,
i' = 19.6 +/- 0.1 mag,
z' = 19.4 +/- 0.1 mag,
J = 19.4 +/- 0.2 mag, and
H = 19.2 +/- 0.2 mag.
The magnitudes are calibrated against SDSS and 2MASS field stars and are
not corrected for the Galactic foreground extinction corresponding to a
reddening of E_(B-V)= 0.05 in the direction of the burst (Schlegel et al.
1998).
GCN Circular 17080
Subject
GRB 141121A: Enhanced Swift-XRT position
Date
2014-11-21T10:50:36Z (11 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 1073 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 141121A, 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 = 122.66947, +22.21741 which is equivalent
to:
RA (J2000): 08h 10m 40.67s
Dec (J2000): +22d 13' 02.7"
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 17081
Subject
GRB 141121A: Keck redshift
Date
2014-11-21T12:23:41Z (11 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley, C. P. Ott (Caltech), M. Modjaz, and D. Fierroz (NYU) report:
We acquired a spectrum of the afterglow of GRB 141121 (Lien et al., GCN
17075; Tanga et al., GCN 17078) using the Low-Resolution Imaging
Spectrometer (LRIS) on the Keck I 10-meter telescope. A single exposure
of 900 seconds was acquired using the B600 and R400 gratings, covering a
wavelength range from 3116 to 10264 Angstroms.
In the reduced spectrum, we identify the Mg II (2796,2803) doublet, the
Fe II (2599) doublet, Fe II (2585), and Fe II (2344) at a common
redshift of z=1.47 (as well as many absorption lines at bluer
wavelengths). No higher-redshift absorption systems are observed and no
DLA is present down to the blue limit of our spectrum (suggesting an
upper limit of z<1.56) so we associate this with the redshift of the GRB.
GCN Circular 17082
Subject
GRB 141121A: LCO-FTN observations
Date
2014-11-21T12:46:18Z (11 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
S. Dichiara and C. Guidorzi (U. Ferrara) on behalf of
a large collaboration report:
The Las Cumbres Observatory 2-m Faulkes Telescope North in
Hawaii began observing Swift GRB 141121A (Lien et al. GCN
Circ 17075) on November 21 at 10:42:54 UT, i.e. ~6.9 hours
after the BAT trigger, with the r' and i' filters.
We clearly detect the optical afterglow (Tanga et al.
GCN 17078; Perley et al. GCN 17081) with the following
magnitudes:
Mid time from Total Exp Filter Magnitude
trigger (hr) (s)
-------------------------------------------------
7.0 120x5 r' 19.62 +- 0.06
7.2 120x5 i' 19.42 +- 0.06
-------------------------------------------------
Magnitudes are calibrated against nearby SDSS stars.
Compared with GROND values we note a possible hint
for rebrightening or, in any case, for a very shallow
decay between the two epochs.
GCN Circular 17083
Subject
GRB 141121A: Swift-BAT refined analysis
Date
2014-11-21T14:40:09Z (11 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (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-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 141121A (trigger #619182)
(Lien, et al., GCN Circ. 17075). The BAT ground-calculated position is
RA, Dec = 122.665, 22.206 deg which is
RA(J2000) = 08h 10m 39.5s
Dec(J2000) = +22d 12' 22.5"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
The mask-weighted light curve shows a very broad multi-peaked structure with the
first emission episode running from T-50 to T+450 sec, with at least four
superimposed peaks. Then there is a return to baseline followed by another
episode from T+550 to T+675 sec. The spacecraft slewed away from the burst
position at around T+825 sec. T90 (15-350 keV) is 549.9 +- 37.4 sec (estimated
error including systematics).
The time-averaged spectrum from T+46.54 to T+663.07 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.73 +- 0.13. The fluence in the 15-150 keV band is 5.3 +- 0.4 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+230.14 sec in the 15-150 keV band
is 0.9 +- 0.3 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/619182/BA/
GCN Circular 17084
Subject
GRB 141121A: RATIR Optical Observations
Date
2014-11-21T17:02:31Z (11 years ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Alan M. Watson (UNAM), Nat Butler (ASU), 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 141121A (Lien et al., GCN 17075) 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 2014/11 21.33 to 2014/11 21.53 UTC (4.00 to 8.84 hours after
the BAT trigger), obtaining a total of 3.78 hours exposure in the r, i and z
bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS DR9,
we obtain the following detections:
r 19.62 +/- 0.02
i 19.45 +/- 0.02
z 19.76 +/- 0.12
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
Over the course of our observations, the flux in r and i fades slightly as
t^-0.15, with t measured from the time of the BAT trigger. Our measurements in z
are noisier, but consistent with this shallow decay.
We confirm this as the afterglow reported by Tanga et al. (GCN 17078) and
Dichiara et al. (GCN 17082), for which Perley et al. (GCN 17081) report a
spectroscopic redshift of 1.47.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro M��rtir.
The RATIR team congratulates the Swift team on 10 years of operation.
GCN Circular 17085
Subject
GRB 141121A: Swift/UVOT Detections
Date
2014-11-21T19:03:15Z (11 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 141121A
371 s after the BAT trigger (Lien et al., GCN Circ. 17075).
A source consistent with the optical position
(Tanga et al. GCN Circ. 17078)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 08:10:40.63 = 122.66928 (deg.)
Dec (J2000) = 22:13:02.2 = 22.21728 (deg.)
with an estimated uncertainty of 0.5 arcsec. (radius, 90% confidence).
The source shows an unusual light curve with little evidence for variability.
The source is detected in all UVOT filters although the detections in v and w2
are not highly significant. 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 371 520 147 >20.1
white 6067 6266 197 20.2 +/- 0.2
v 527 547 19 >18.3
v 15373 16025 635 20.3 +/- 0.3
b 5862 6062 197 19.8 +/- 0.2
u 5562 5714 149 19.4 +/- 0.2
u 27756 28325 556 19.3 +/- 0.1
w1 3830 3897 66 19.4 +/- 0.3
w1 26850 27750 886 19.7 +/- 0.1
m2 21039 21939 886 20.4 +/- 0.2
w2 9514 12083 771 21.2 +/- 0.3
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 17086
Subject
GRB 141121A: Swift-XRT refined Analysis
Date
2014-11-22T00:08:04Z (11 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
D.N. Burrows (PSU), C. Pagani (U. Leicester), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), B. Sbarufatti (INAF-OAB/PSU), P.
D'Avanzo (INAF-OAB), V. D'Elia (ASDC), J.A. Kennea (PSU), V. Mangano
(PSU) and A.Y. Lien report on behalf of the Swift-XRT team:
We have analysed 7.3 ks of XRT data for GRB 141121A (Lien et al. GCN
Circ. 17075), from 355 s to 58.1 ks after the BAT trigger. The data
comprise 305 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 Evans et
al. (GCN Circ. 17080).
The late-time light curve (from T0+3.8 ks) can be modelled with a
series of power-law decays. The initial decay index is alpha=1.50
(+/-0.13). At T+15.8 ks the decay steepens to an alpha of 4.3 (+1.2,
-0.7) before breaking again at T+25.6 ks to a final decay with index
alpha=0.1 (+0.6, -1.5).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.52 (+/-0.04). The
best-fitting absorption column is 6.2 (+/-1.0) x 10^21 cm^-2, at a
redshift of 1.47, in addition to the Galactic value of 4.3 x 10^20
cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index
of 1.93 (+/-0.12) and a best-fitting absorption column of 3.9 (+2.2,
-2.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV
flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (4.1
x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 4.3 x 10^20 cm^-2
Intrinsic column: 3.9 (+2.2, -2.0) x 10^21 cm^-2 at z=1.47
Photon index: 1.93 (+/-0.12)
If the light curve continues to decay with a power-law decay index of
0.1, the count rate at T+24 hours will be 0.032 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (1.3 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/00619182.
This circular is an official product of the Swift-XRT team.
GCN Circular 17087
Subject
GRB 141121A: Continued RATIR Optical Observations
Date
2014-11-23T07:05:41Z (11 years ago)
Edited On
2024-11-07T19:53:36Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
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), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on
Sierra San Pedro Mártir from 2014/11 22.28 to 2014/11 22.53 UTC (26.79
to 32.94 hours after the BAT trigger), obtaining a total of 4.93 hours
exposure in the r, i and z bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS
DR9, we
obtain the following detections and upper limits (3-sigma):
r 20.84 +/- 0.03
i 20.68 +/- 0.03
z > 20.02
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
The source has faded in r and i by 1.2 magnitudes or roughly t^-0.73 since
our observations on the first night (Watson et al., GCN 17084), confirming
that it is the afterglow. This fading is steeper than the t^-0.15 fading
seeing during our observations on the first night.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 17088
Subject
GRB 141121A: MITSuME Akeno Optical observation
Date
2014-11-23T11:44:55Z (11 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
S. Kurita, Y. Saito, Y. Tachibana, T. Yoshii, H. Ohuchi, Y. Yano,
Y. Ono, T. Fujiwara, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We observed the field of GRB 141121A (Lien et al., GCN Circular #17075) with the
optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2014-11-21 12:59:47 UT (~9 h after the burst).
We detected the previously reported optical afterglow (Tanga et al., GCN Circular #17078) in the g',Rc and Ic band.
The measured magnitudes are listed below.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
----------------------------------------------------------------------
32947 17:07:07 12840 20.8 +/- 0.2 19.7 +/- 0.1 19.4 +/- 0.2
----------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 17089
Subject
GRB 141121A: AAO optical observations
Date
2014-11-23T13:36:48Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.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 GRB 141121A (Lien et al., GCN 17075) with AS-32
(0.7m) telescope of Abastumani Observatory. Observations were performed
under mean seeing (FWHM) of 3.5". We obtained several unfiltered images
on Nov. 21 starting on (UT) 20:01:35. Within enhanced XRT position
(Evans et al., GCN 17080) we clearly detected afterglow of GRB 141109A
(Tanga et al., GCN 17078; Perley et al., GCN 17081). Preliminary
photometry is following:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-21 20:01:35 0.73241 clear 54*120 20.08 0.05
The photometry is based on several SDSS-DR9 stars R magnitudes
transformed from SDSS-DR9 based on Lupton transformations:
SDSS_id R(Lupton)
J081028,70+221318,9 16,317
J081049,68+221012,2 17,148
J081048,76+220822,7 14,413
J081106,66+221346,9 14,626
GCN Circular 17090
Subject
GRB 141121A: Continued RATIR Optical Observations - Rebrightening
Date
2014-11-23T16:20:16Z (11 years ago)
Edited On
2024-11-07T20:00:00Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), 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), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on
Sierra San Pedro Mártir from 2014/11 23.31 to 2014/11 23.54 UTC (51.53
to 57.18 hours after the BAT trigger), obtaining a total of 3.80 hours
exposure in the r, i and z bands.
For a source within the Swift-XRT error circle, in comparison with the
SDSS DR9, we obtain the following detections:
r = 20.60 +/- 0.03
i = 20.44 +/- 0.03
z = 20.06 +/- 0.29
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
The afterglow appears to have rebrightened by about 0.24 magnitudes in
r and i compared to our observations at 30 hours (Butler et al., GCN
17087).
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 17091
Subject
GRB 141121A: MITSuME Ishigakijima Optical Observation
Date
2014-11-24T01:39:20Z (11 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 141121A (Lien et al., GCNC 17075)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
The observation started on 2014-11-23 17:42:18 UT (~2.6 days after the burst).
We detected the previously reported afterglow (Tanga et al., GCNC 17078;
Perley et al., GCNC 17081) in all the three bands.
Photometric results of the OT are listed below.
We used SDSS-DR7 catalog for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err
--------------------------------------------------------------------------
2.61049 18:29:49 4800.0 21.02 0.08 20.44 0.07 19.64 0.09
--------------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 17092
Subject
GRB 141121A: LCO-FTN rebrightening confirmation
Date
2014-11-24T09:58:43Z (11 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
S. Dichiara and C. Guidorzi (U. Ferrara) on behalf of
a large collaboration report:
The Las Cumbres Observatory 2-m Faulkes Telescope North in
Hawaii re-observed Swift GRB 141121A (Lien et al. GCN
Circ 17075) on November 23 at 10:43:39 UT, i.e. ~2.29 days
after the BAT trigger, with the r' and i' filters.
We confirm the rebrightening of the optical afterglow
reported by RATIR (Watson et al. GCN 17090) with the
following magnitudes:
Mid time from Total Exp Filter Magnitude
trigger (days) (s)
-------------------------------------------------
2.31 120x10 r' 20.61 +- 0.04
2.29 120x10 i' 20.34 +- 0.05
-------------------------------------------------
Magnitudes are calibrated against nearby SDSS stars.
Observations are going on.
GCN Circular 17093
Subject
GRB 141121A: Mondy optical observations
Date
2014-11-24T16:56:28Z (11 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 GRB 141121A (Lien et al., GCN 17075) with
AZT-33IK telescope of Sayan observatory (Mondy) on Nov., 23 starting on
(UT) 20:57:39. We obtained several images in R-filter. In a combined
image we clearly detect optical afterglow (Tanga et al., GCN 17078;
Perley et al., GCN 17081).
A preliminary photometry is based on nearby SDSS stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-23 20:57:39 2.74025 R 39*120 20.53 0.04
We confirm re-brightening of the afterglow reported early (Watson et al.
GCN 17090; Kuroda et al. GCN 17091; Dichiara et al. GCN 17092).
GCN Circular 17096
Subject
GRB 141121A: RATIR Optical Observations - Fading Again
Date
2014-11-24T18:04:30Z (11 years ago)
Edited On
2024-11-07T18:46:37Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
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), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on
Sierra San Pedro Mártir from 2014/11 24.27 to 2014/11 24.53 UTC (74.70
to 80.86 hours after the BAT trigger), obtaining a total of 4.93 hours
exposure in the r, i, and z band.
For a source within the Swift-XRT error circle, in comparison with the
SDSS DR9, we obtain the following detections and upper limits
(3-sigma):
r = 20.68 +/- 0.03
i = 20.51 +/- 0.04
z > 20.48
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
The afterglow has faded by about 0.08 magnitudes in r and i compared
to our observations at 54 hours (Watson et al., GCN 17090). This
corresponds to a shallow decay close to t^-0.2. Thus, the
rebrightening reported by Watson et al. (GCN 17090) and confirmed by
Dichiara et al. (GCN 17092) appears to have ended.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 17098
Subject
GRB 141121A: MITSuME Ishigakijima Optical Observation after 3 days
Date
2014-11-25T01:46:25Z (11 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 141121A (Lien et al., GCNC 17075)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
The observation started on 2014-11-24 17:17:04 UT (~3.6 days after the burst).
We detected the previously reported afterglow (Tanga et al., GCNC 17078;
Perley et al., GCNC 17081; Kuroda et al., GCNC 17091) in all the three bands.
Photometric results of the OT are listed below.
We used SDSS-DR7 catalog for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic Ic_err
--------------------------------------------------------------------------
3.60810 18:26:22 5100.0 21.39 0.13 20.37 0.08 19.90 0.12
--------------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 17099
Subject
GRB 141121A: AMI 15 GHz detection
Date
2014-11-25T17:31:36Z (11 years ago)
From
Gemma Anderson at U of Oxford <gemma.anderson@astro.ox.ac.uk>
G. E. Anderson, R. P. Fender, T. D. Staley (University of Oxford),
A. J. van der Horst (University of Amsterdam), A. Rowlinson (CASS)
We observed the position of GRB 141121A (Lien et al., GCN 17075)
at 15 GHz with the Arcminute Microkelvin Imager (AMI-LA) starting on
2014 Nov 24.17 to 24.33 UT, corresponding to 3 days post-burst. We
have detected a radio source coincident with the optical counterpart
(Tanga et al., GCN 17078) with a preliminary flux of 0.46 +/- 0.05 mJy.
Earlier observations were conducted on 2014 Nov 21.16 to 21.25 UT and
Nov 22.05 to 22.21 UT, corresponding to <6 minutes and 0.9 days post-burst,
yielding a 3 sigma flux upper limit of 0.26 mJy and a marginal detection of
0.18 +/- 0.06 mJy, respectively.
Further AMI monitoring is planned. We thank the AMI staff for scheduling these observations.
GCN Circular 17100
Subject
GRB 141121A: RATIR Optical Observations - Steeper Fading
Date
2014-11-25T18:21:54Z (11 years ago)
Edited On
2024-11-07T18:59:00Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), 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), José A. de Diego (UNAM), Leonid Georgiev (UNAM),
Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC),
and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on
the 1.5m Harold Johnson Telescope at the Observatorio Astronómico
Nacional on Sierra San Pedro Mártir from 2014/11 25.27 to 2014/11 25.54
UTC (98.75 to 105.00 hours after the BAT trigger), obtaining a total of
4.58 hours exposure in the r, i, and z bands.
For a source within the Swift-XRT error circle, in comparison with the
SDSS DR9, we obtain the following detections and upper limits (3-sigma):
r = 20.96 +/- 0.04
i = 20.75 +/- 0.04
z > 19.93
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
The afterglow has faded by about 0.25 magnitudes in r and i compared to
our observations at 78 hours (Butler et al., GCN 17096). This
corresponds to a steepening of the temporal power law from t^-0.2
between 54 and 78 hours (Butler et al., GCN 17096) to t^-0.9 between 78
and 102 hours.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 17101
Subject
GRB 141121A: Continued RATIR Optical Observations
Date
2014-11-26T16:47:33Z (11 years ago)
Edited On
2024-11-07T18:52:13Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
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), José A. de Diego (UNAM), Leonid Georgiev
(UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels
(GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on
the 1.5m Harold Johnson Telescope at the Observatorio Astronómico
Nacional on Sierra San Pedro Mártir from 2014/11 26.31 to 2014/11 26.53
UTC (123.55 to 128.80 hours after the BAT trigger), obtaining a total of
4.04 hours exposure in the r, i and z bands.
For a source within the Swift-XRT error circle, in comparison with the
SDSS DR9, we obtain the following detections and upper limits (3-sigma):
r = 21.27 +/- 0.04
i = 21.04 +/- 0.04
z > 21.04
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
The afterglow has faded by about 0.3 magnitudes in r and i compared to
our observations at 102 hours (Watson et al., GCN 17100). This
corresponds to a further steepening of the temporal power law from
t^-0.9 between 78 and 102 hours (Watson et al., GCN 17100) to t^-1.3
between 102 and 126 hours.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro
Mártir.
GCN Circular 17102
Subject
GRB 141121A: Continued Mondy optical observations
Date
2014-11-26T22:52:46Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), M. Eselevich
(ISTP), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger
GRB follow-up collaboration:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with
AZT-33IK telescope of Sayan observatory (Mondy) on Nov., 26 starting on
(UT) 20:16:58. We obtained several images in R-filter. In a combined
image we clearly detect optical afterglow (Tanga et al., GCN 17078;
Perley et al., GCN 17081).
A preliminary photometry is based on nearby SDSS stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-26 20:16:58 5.7120 R 39*120 21.38 0.09
The magnitude of the afterglow decreased about 0.9 mag since our
previous observation (Mazaeva et al., GCN 17093) at 2.74 days after the
burst trigger and thus we confirm gradual steepening of the afterglow
light curve (Butler et al., GCN 17101).
GCN Circular 17103
Subject
GRB 141121A: TSHAO optical observations
Date
2014-11-27T00:21:38Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin
(Fesenkov Astrophysical Institute), E. Mazaeva (IKI), A. Pozanenko (IKI)
report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 141121A (Lien et al., GCN 17075)
with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical
Observatory starting on Nov. 22 (UT) 21:45:26. We obtained several
images in R-filter. In a combined image we clearly detect optical
afterglow (Tanga et al., GCN 17078; Perley et al., GCN 17081).
A preliminary photometry is based on nearby SDSS DR9 stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-22 21:45:26 1.8093 R 26*300 20.88 0.03
GCN Circular 17104
Subject
GRB 141121A: WSRT radio detection
Date
2014-11-27T13:34:17Z (11 years ago)
From
Alexander van der Horst at U of Amsterdam <A.J.vanderHorst@uva.nl>
A.J. van der Horst (University of Amsterdam) reports on behalf
of a large collaboration:
"We observed the position of the GRB 141121A afterglow at 4.9 GHz with
the Westerbork Synthesis Radio Telescope at November 26 22.54 UT to
November 27 09.34 UT, i.e. 5.78 - 6.23 days after the burst (GCN 17075).
We detect a radio source with a flux density of 0.17 +/- 0.04 mJy
at the position of the optical counterpart (GCN 17078).
We would like to thank the WSRT staff for scheduling and obtaining
these observations."
GCN Circular 17105
Subject
GRB 141121A: Continued RATIR Optical Observations
Date
2014-11-27T16:16:55Z (11 years ago)
Edited On
2024-11-07T19:14:55Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), 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), José
A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos
Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m
Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San
Pedro Mártir from 2014/11 27.31 to 2014/11 27.54 UTC (147.50 to 153.22 hours
after the BAT trigger), obtaining a total of 4.62 hours exposure in the r, i and
z bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS DR9,
we obtain the following detections:
r = 21.59 +/- 0.04
i = 21.39 +/- 0.04
z = 20.89 +/- 0.26
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
The afterglow has faded by about 0.33 magnitudes in r and i compared to our
observations at 126 hours (Butler et al., GCN 17101). This corresponds to a
further steepening of the temporal power law from t^-1.3 between 102 and 126
hours (Watson et al., GCN 17100) to t^-1.8 between 126 and 150 hours.
We detect a source 2.3 arcsec to the east of the optical transient, with r =
23.22 +/- 0.13, i = 23.11 +/- 0.13, and z > 21.02. This source is visible in
earlier images, but due to its proximity to the brighter optical transient our
automatic pipeline failed to produce photometry for it from those earlier
images. We expect better photometry for this source once the afterglow has faded
further.
For a flat universe with H0 = 70 km/s/Mpc and OmegaM = 0.29, and at a redshift
of 1.47 (Perley et al., GCN 17081) the angular separation of the afterglow and
this source corresponds to a projected separation of 20 kpc. This separation is
consistent with the source being the host galaxy of the GRB.
If this source is the host galaxy, our photometry suggests that it is among the
brightest ever observed at this redshift for optically bright GRBs (Hjorth et
al. 2012, ApJ, 756, 187; Perley et al. 2013, ApJ, 778, 128).
We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN Circular 17106
Subject
GRB 141121A: three epochs of SAO RAS optical observations
Date
2014-11-27T18:23:54Z (11 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
A.S. Moskvitin and V.N. Komarova report on behalf of a larger team:
We observed the field of GRB 141121A (Lien et al., GCN 17075)
with the SAO RAS 1-m Zeiss-1000 telescope at three nights:
2014.11.24/25, 25/26, 26/27.
The GRB OT (Tanga et al., GCN 17078) is clearly detected
in our stacked frames each night. Our charts can be found at
ftp://ftp.sao.ru/pub/grb/GRB141121A/GRB141121A_z1000_24_25_26.jpg
We used nearby SDSS stars for calibration. The "ugriz" magnitudes
were converted to "UBVRI" with the Lupon-2005 equations. Our OT
brightness measurements are in good agreement with R-band values
estimated within the close epochs and reported in the GCN circulars:
Kuroda et al. (GCN 17098), Mazaeva et al. (GCN 17102). Our OT
magnitudes are also similar to r-band measurements by Watson et al.
(GCN 17100) and Butler et al. (GCN 17101).
Our preliminary results are presented in the following table:
-----------------------------------------------------
Date T-T0 UT_start-end Exp.,s R_mag
-----------------------------------------------------
24.942 3.782 20:14--00:59 900 20.31+/-0.09
25.956 4.796 22:16--23:38 3600 20.86+/-0.04
26.980 5.820 22:12--00:50 4800 21.36+/-0.09
-----------------------------------------------------
GCN Circular 17108
Subject
Konus-Wind observation of GRB 141121A
Date
2014-11-28T14:34:54Z (11 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 141121A (Swift-BAT trigger #619182: Lien et al., GCN 17075;
Krimm et al., GCN 17083; MAXI/GSC detection: Honda et al., GCN 17077)
was detected by Konus-Wind in the waiting mode.
The burst light curve shows two emission episodes. The first started at
~T0(BAT)-870 s with a duration of about 190 s and the second weaker
episode, which corresponds to the first BAT episode reported in GCN
17075, started at ~T0(BAT)+50 s with a duration of about 270 s. The
second BAT episode (from T0(BAT)+550 to T0(BAT)+675 s) is not seen in KW
data.
The first KW episode is likely related to GRB 141121A, since the KW
ecliptic latitude response and IPN localization of the episode are
consistent with the position of GRB 141121A. The details of the IPN
localization will be given in a forthcoming GCN circular. During the
first episode the burst source was outside the BAT FoV (private
communication with the BAT team).
The total burst duration is about 1200 s. Such a long duration and long
periods of low-level emission or quiescence is common for ultra-long GRB.
The KW light curve contains several data gaps. One of them (from
~T0(BAT)-670 s to ~T0(BAT)-270 s) may bias the estimated duration of the
first episode. The MAXI/GSC detection at ~T0(BAT)-356 s falls into this gap.
As observed by Konus-Wind, the first episode had a fluence of ~8x10^-6
erg/cm2 and a 2.944 s peak flux, measured from ~T0(BAT)-752 s, of
~2x10^-7 erg/cm2/s (both estimated in the 20 keV - 10 MeV energy
range). The second episode had a fluence of ~6x10^-6 erg/cm2 estimated
in the same energy range.
Assuming the redshift z=1.47 (Perley et al., GCN 17081)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~8x10^52 erg,
the peak luminosity L_iso is ~10^51 erg/s.
The K-W light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB141121A/
GCN Circular 17109
Subject
GRB 141121A: RATIR Optical and NIR Observations
Date
2014-11-28T16:04:21Z (11 years ago)
Edited On
2024-11-07T18:48:12Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
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), José
A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos
Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m
Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San
Pedro Mártir from 2014/11 28.29 to 2014/11 28.54 UTC (171.20 to 177.06 hours
after the BAT trigger), obtaining a total of 4.62 hours exposure in the r, i,
and z bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS DR9,
we obtain the following detections and upper limits (3-sigma):
r = 21.87 +/- 0.05
i = 21.62 +/- 0.05
z > 21.03
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
Compared to our previous observations (Butler et al., GCN 17101; Watson et al.,
GCN 17105), the afterglow continues to fade roughly as t^-1.7.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN Circular 17110
Subject
GRB 141121A: SPI-ACS/INTEGRAL observations
Date
2014-11-28T18:10:04Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), P. Minaev (IKI), V. Vybornov (IKI), A. Volnova
(IKI), E. Mazaeva (IKI) report:
We inspected the SPI-ACS data of INTEGRAL observatory covering trigger
time of the Swift GRB 141121A (Lien et al., GCN 17075) and MAXI/GSC
(Honda et al., GCN 17077). At the BAT/Swift trigger time of the GRB
141121A (UT) T0=03:50:43 we do not found any significant emission above
background in SPI-ACS data in different time scales (0.05 s, 5 s, and 50
s). We also do not find any activity at the second BAT episode (T0+550
s to T0+675 s).
At the time of about T0-800 s we found in SPI-ACS data the activity
corresponding to the first Konus-Wind episode (Golenetskii et al., GCN
17108). The duration of the activity is about 200 s and clearly visible
in SPI-ACS light curve. The start time of the maximal count rate of
SPI-ACS light curve (binning with 50 s bin duration) is T0-725 s. In
both cases TO and T0-725 s the boresight of SPI-ACS is the same and
equal to 119 degrees. If this episode is related to the GRB 141121A and
taking into account SPI-ACS energy threshold (>~ 80 keV) one can suggest
the this episode of GRB 141121A is harder than main activity detected by
BAT/Swift.
We do not detect any significant activity at the time of the MAXI/GSC
detection (Honda et al., GCN 17077).
The SPI-ACS light curves can be found at
http://grb.rssi.ru/GRB141121A/grb141121_spi-acs_50sec.png
http://grb.rssi.ru/GRB141121A/grb141121_spi-acs_5sec.png
GCN Circular 17111
Subject
GRB 141121A: Mondy optical observations
Date
2014-11-28T19:21:59Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev
(ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with
AZT-33IK telescope of Sayan observatory (Mondy) on Nov., 27 starting
(UT) 19:13:37. We obtained several images in R-filter ander favorable
weather and mean FWHM of 1.8 arcsec. In a combined image we clearly
detect optical afterglow (Tanga et al., GCN 17078; Perley et al., GCN
17081). We do not detect the nearby source reported in (Watson et al.,
GCN 17075). Instead of we detect a Source (possible host?) 3 arcsec to
the West from OT. The Source is absent in SDSS DR9. Coordinates of the
OT and the Source are
OT
(J2000)
08 10 40.55 +22 13 03.0
with accuracy of 0.4" in both coordinates
The Source to the West
(J2000)
08 10 40.35 +22 13 03.0
with accuracy of 0.5" in both coordinates
Astrometry solutions are based on USON-B1.0 catalog.
A preliminary photometry of the OT is based on nearby SDSS stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-27 19:13:37 6.6923 R 72*120 21.57 0.05
And preliminary photometry of the Source is R 22.95 �� 0.11.
The source is barely visible in our earlier observations (Mazaeva et
al., GCN 17102) and photometry of the early observation reported in
(Mazaeva et al., GCN 17102) might be biased of this Source.
The finding chart can be found in
http://grb.rssi.ru/GRB141121A/GRB141121A.Mondy_host_chart.png
GCN Circular 17112
Subject
IPN Triangulation of GRB 141121A (initial episode)
Date
2014-11-28T20:00:34Z (11 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team,
S. Golenetskii, R. Aptekar, V. Pal'shin, D. Frederiks,
D. Svinkin, and T. Cline on behalf of the Konus-Wind team,
S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team, and
A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C.
Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report:
The possible initial emission episode of GRB 141121A reported by
Konus-Wind (Golenetskii et al., GCN Circ. 17108) has been also observed
by INTEGRAL (SPI-ACS) and MESSENGER (GRNS) at about 13083 s UT
(03:38:03; =T0(BAT)-760 s), so far.
We have triangulated it to a INTEGRAL-MESSENGER annulus centered at
RA(2000)=46.543 deg (03h 06m 10s) Dec(2000)=+16.630 deg (+16d 37' 49"),
whose radius is 71.291 +/- 0.356 deg (3 sigma).
The distance between the Swift-XRT position of GRB 141121A (Evans et
al., GCN Circ. 17080) and the central line of the annulus is 32 arcsec,
which strengthen the association of the episode with GRB 141121A.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB141121A/IPN/
GCN Circular 17113
Subject
GRB 141121A: Khureltogot optical observations
Date
2014-11-28T22:40:39Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.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 We observed the field of GRB 141121A (Lien et
al., GCN 17075) with ORI-40 telescope of Khureltogot observatory. We
obtained several images in R-filter on Nov. 21 starting on (UT)
17:07:01. In a combined image we marginally detect optical afterglow
(Tanga et al., GCN 17078; Perley et al., GCN 17081). Preliminary
photometry is following and based on nearby SDSS DR9 stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-21 17:07:01 0.5977 R 120*60 19.0 0.3
GCN Circular 17114
Subject
GRB 141121A: MITSuME Ishigakijima Optical Observation after 7 days
Date
2014-11-29T02:41:50Z (11 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ),
K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima),
K. Ohta (Kyoto) and N. Kawai(Tokyo Tech)
report on behalf of the MITSuME and OISTER collaboration:
We observed the field of GRB 141121A (Lien et al., GCNC 17075)
with the optical three color (g', Rc and Ic) CCD camera attached
to the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
The observation started on 2014-11-28 15:13:00 (~7.5 days after the burst).
We detected the previously reported afterglow (Tanga et al., GCNC 17078;
Perley et al., GCNC 17081; Kuroda et al., GCNC 17091) in g' and Rc bands.
Three sigma upper limit and photometric results of the OT are listed below.
We used SDSS-DR7 catalog for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' g'_err Rc Rc_err Ic
--------------------------------------------------------------------------
7.50078 15:51:50 2400.0 21.9 0.3 21.0 0.2 >20.5
--------------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 17115
Subject
GRB 141121A: RATIR Optical Observations - Errata for GCN 17105
Date
2014-11-29T04:27:02Z (11 years ago)
Edited On
2024-11-07T19:55:53Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), 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), José
A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos
Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We wish to correct an error in our earlier report of a faint source close to GRB
141121A (Watson et al., GCN 17105). The faint source is to the WEST of the
afterglow, not to the EAST as we reported. With this correction, our earlier
report and that of Mazaeva et al. (GCN 17111) are now in agreement.
Our preliminary astrometry, based on SDSS DR9, for the afterglow is:
08:10:40.61 +22:13:01.7 J2000
and for the fainter source:
08:10:40.41 +22:13:01.8 J2000
This astrometry may be refined as the afterglow fades and fainter source becomes
more clearly separated.
We thank Mazaeva et al. (GCN 17111) for bringing this error to our attention.
GCN Circular 17116
Subject
GRB 141121A: Continued RATIR Optical Observations
Date
2014-11-29T16:15:21Z (11 years ago)
Edited On
2024-11-07T18:51:36Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), 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), José
A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos
Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m
Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San
Pedro Mártir from 2014/11 29.29 to 2014/11 29.53 UTC (195.13 to 200.87 hours
after the BAT trigger), obtaining a total of 4.62 hours exposure in the r, i and
z bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS DR9,
we obtain the following detections and upper limits (3-sigma):
r = 22.15 +/- 0.06
i = 21.97 +/- 0.06
z > 21.04
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
The afterglow continues to fade with a steepening temporal index.
We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN Circular 17117
Subject
GRB 141121A: TSHAO optical observations
Date
2014-11-29T18:03:22Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), A.
Volnova (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 141121A (Lien et al., GCN 17075)
with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical
Observatory starting on Nov. 26 (UT) 22:12:24. We obtained several
images in R-filter. In a combined image we clearly detect optical
afterglow (Tanga et al., GCN 17078; Perley et al., GCN 17081).
A preliminary photometry is based on nearby SDSS DR9 stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-26 22:12:24 5.8118 R 14*300 21.48 0.09
GCN Circular 17118
Subject
GRB 141121A: Mondy optical observations
Date
2014-11-30T14:40:57Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev
(ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with
AZT-33IK telescope of Sayan observatory (Mondy) Nov., 29 starting on
(UT) 20:20:38. We obtained several images in R-filter under
unfavorable seeing. In a combined image we detect optical afterglow
(Tanga et al., GCN 17078; Perley et al., GCN 17081).
A preliminary photometry of the OT is based on nearby SDSS DR9 stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-29 20:20:38 8.7458 R 84*120 22.03 0.17
Due to bad seeing the photometry above includes both afterglow and
possible host (Watson et al., GCN 17105; Mazaeva et al., GCN 17111).
GCN Circular 17119
Subject
GRB 141121A: Continued RATIR Optical Observations
Date
2014-11-30T17:27:01Z (11 years ago)
Edited On
2024-11-07T19:56:45Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
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), José
A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos
Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m
Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San
Pedro Mártir from 2014/11 30.28 to 2014/11 30.54 UTC (218.99 to 225.08 hours
after the BAT trigger), obtaining a total of 4.98 hours exposure in the r, i and
z bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS DR9,
we obtain the following detections and upper limits (3-sigma):
r = 22.32 +/- 0.07
i = 22.14 +/- 0.07
z > 21.00
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 Astronómico Nacional in San Pedro Mártir.
GCN Circular 17124
Subject
GRB 141121A: VLA radio detection
Date
2014-12-01T05:54:12Z (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 imaged the position of GRB 141121A (Lien et al., GCN 17075) with the Karl G. Jansky
Very Large Array (VLA), at a mean epoch of about 8.4 days after the burst. We detect the
radio afterglow of GRB 141121A (Anderson et al., GCN 17099; van der Horst, GCN 17104)
at a position consistent with the optical counterpart (Tanga et al., GCN 17078). At this time,
we estimate a preliminary flux of about 207 uJy at 14 GHz. The map rms is about 5 uJy.
GCN Circular 17128
Subject
GRB 141121A: Continued RATIR Optical Observations
Date
2014-12-01T16:07:08Z (11 years ago)
Edited On
2024-11-07T19:35:31Z (8 months ago)
From
Alan M. Watson at Instituto de Astronomia UNAM <alan@astro.unam.mx>
Edited By
Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov> on behalf of Leo P. Singer at NASA/GSFC <leo.p.singer@nasa.gov>
Alan M. Watson (UNAM), Nat Butler (ASU), 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), José
A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos
Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m
Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San
Pedro Mártir from 2014/12 1.30 to 2014/12 1.54 UTC (243.35 to 249.19 hours after
the BAT trigger), obtaining a total of 4.56 hours exposure in the r, i, and z
bands.
For a source within the Swift-XRT error circle, in comparison with the SDSS, we
obtain the following detections and upper limits (3-sigma):
r = 22.38 +/- 0.16
i = 22.21 +/- 0.16
z > 20.41
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
Compared to our observations on previous nights (Watson et al., GCN 17116;
Butler et al., GCN 17119), the fading appears to be slowing and is now behaving
as t^-0.5. This may be evidence for an underlying host galaxy more closely
coincident with the GRB than the candidate reported by Watson et al. (GCN
17105).
We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN Circular 17138
Subject
GRB 141121A: Mondy optical observations
Date
2014-12-05T14:58:30Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev
(ISTP), M. Eselevich (ISTP), A. Pozanenko (IKI) report on behalf of
larger GRB follow-up collaboration:
We continue observations of the field of GRB 141121A (Lien et al., GCN
17075) with AZT-33IK telescope of Sayan observatory (Mondy). We obtained
several images in R-filter on Nov., 30, Dec. 1 - 2. In a combined image
we detect optical afterglow (Tanga et al., GCN 17078; Perley et al.,
GCN 17081).
A preliminary photometry of the OT is based on nearby SDSS DR9 stars:
date UT start t-T0 Filter Exp. OT OT_err
(mid, days) (s)
2014-11-30 18:45:29 9.7139 R 119*120 22.20 0.10
2014-12-01 18:35:23 10.6644 R 72*120 22.25* 0.17
2014-12-02 18:09:52 11.6606 R 92*120 22.40* 0.25
*)Due to bad seeing the photometry includes both afterglow and nearby
source (Watson et al., GCN 17105; Mazaeva et al., GCN 17111).
GCN Circular 17145
Subject
GRB141121A: Discovery Channel Telescope Optical Observations
Date
2014-12-07T21:48:55Z (11 years ago)
From
Vicki Toy at UMD <vtoy@astro.umd.edu>
V. Toy (UMD), J. Capone (UMD), A. Cucchiara (NASA-GSFC), S.B. Cenko
(NASA-GSFC), E. Troja (NASA-GSFC), A. Kutyrev (NASA-GSFC), and S. Veilleux
(UMD) report on behalf of a larger collaboration:
We observed the field of GRB141121A (Swift trigger 619182, Lien et al., GCN
17075) with the Large Monolithic Imager (LMI) on the 4.3m Discovery Channel
Telescope (DCT) at Happy Jack, AZ from 2014/12/07 6:44 to 2014/12/07 11:01
UTC (starting 386.1 hours after the Swift trigger). A source is clearly
detected at the location of the optical afterglow in g', r', i', and z'.
Using nearby point sources from SDSS R8 for calibration we measure i' =
23.26 +/- 0.12.
This magnitude is reported in AB magnitude and is not corrected for
Galactic extinction in the direction of the GRB.
Compared to RATIR observations on 12/01 (Watson, GCN 17128) the afterglow
has steepened to a decay index of ~ t^-2.1. At this time we cannot confirm
if this is the host galaxy. Further observations are planned.
We thank the staff of the Discovery Channel Telescope for assistance with
these observations.
GCN Circular 17156
Subject
GRB 141121A: further VLA observations
Date
2014-12-10T03:48:36Z (11 years ago)
From
Alessandra Corsi at Texas Tech U <alessandra.corsi@ttu.edu>
A. Corsi (Texas Tech U.), S.B. Cenko (NASA-GSFC), A. Cucchiara (NASA-GSFC),
D. A. Perley (Caltech), A. Horesh (Weizmann Institute), D. A. Frail (NRAO) report:
We imaged again the the position of GRB 141121A (Lien et al., GCN 17075) with
the Karl G. Jansky Very Large Array (VLA), at a mean epoch of about 16.3 days
after the burst. At this time, we detect the radio afterglow of GRB 141121A
(Anderson et al., GCN 17099; van der Horst, GCN 17104; Corsi, GCN 17124),
and estimate a preliminary flux of about 228 uJy at 6.2 GHz and 186 uJy at 14 GHz.
The map rms is about 9 uJy at 6.2 GHz and 7 uJy at 14 GHz.
Further observations are planned.
GCN Circular 17191
Subject
GRB 141121A: Keck observations
Date
2014-12-18T12:15:16Z (11 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) reports:
I observed the location of GRB 141121A (Lien et al., GCN
17075) using the imaging mode of the Low-Resolution Imaging
Spectrometer (LRIS) on the Keck I 10-meter telescope between 10:55 and
11:16 UT on 2014-12-18. A short sequence of exposures in g, R, and
i-bands was acquired.
The optical counterpart (Tanga et al., GCN 17078) is clearly detected in
all filters. Calibrating relative to SDSS, the magnitude is:
i = 23.96 +/- 0.07 (t = 27.3 days)
This measurement is significantly fainter than that reported by Toy et
al. based on DCT observations on 2014-12-07, and the counterpart appears
point-like in 0.8-arcsecond seeing. This suggests that the light is
still dominated by the afterglow.
GCN Circular 17284
Subject
Radio upper limit on the GRB 141121A with the GMRT
Date
2015-01-06T14:20:02Z (10 years ago)
From
Nayana A J at NCRA-TIFR <nayan89deva@gmail.com>
A. J. Nayana (NCRA-TIFR) and Poonam Chandra (NCRA-TIFR) report:
We carried out the Giant Metrewave Radio Telescope (GMRT) observations of
GRB 141121A (GCN Circ 17075) in the 1390 MHz band on 2014 December 22h56m06s UT. We do
not detect radio afterglow of the GRB in this frequency. The 3-sigma upper limit at the
GRB position (GCN Circ. 17078) is 118 uJy.
We thank GMRT staff for making these observations possible.
GCN Circular 17656
Subject
GRB 141121A: GMG observation
Date
2015-03-30T06:23:44Z (10 years ago)
From
Jirong Mao at Yunnan Obs <jirongmao_obs@ynao.ac.cn>
J. Mao, Y. X. Xin, and J.-M. Bai (YNAO) report:
We observed the field of GRB 141121A (Lien et al., GCN 17075) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station
of Yunnan Observatory. We obtain the following results of optical counterpart:
Date begin UT r' begin UT i'
Nov. 21, 2014 17:00:04 20.45+/-0.04 17:41:21 19.90+/-0.03
Nov. 22, 2014 17:57:44 22.46+/-0.09 18:38:40 21.89+/-0.08
Nov. 25, 2014 17:16:11 21.32+/-0.05 17:36:44 20.99+/-0.04
Nov. 27, 2014 18:28:57 22.60+/-0.08 18:49:23 21.99+/-0.05
Due to the poor seeing, we could not distinguish between the afterglow and the possible host galaxy.
J. Mao apologizes for this very late GCN circular submission.