GRB 120729A
GCN Circular 13530
Subject
GRB 120729A: Swift detection of a burst with an optical afterglow
Date
2012-07-29T11:17:04Z (13 years ago)
From
David Burrows at PSU/Swift <burrows@astro.psu.edu>
T. N. Ukwatta (MSU), D. N. Burrows (PSU), M. M. Chester (PSU),
S. T. Holland (STScI), H. A. Krimm (CRESST/GSFC/USRA),
V. Mangano (INAF-IASFPA), A. Maselli (INAF-IASFPA),
E. Sonbas (NASA/GSFC/Adiyaman Univ.) and M. Stamatikos (OSU/NASA/GSFC)
report on behalf of the Swift Team:
At 10:56:14 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120729A (trigger=529095). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 13.056, +49.940 which is
RA(J2000) = 00h 52m 13s
Dec(J2000) = +49d 56' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a FRED-shaped
structure with a total duration of about 25 sec. The peak count rate
was ~5700 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 10:57:22.2 UT, 68.1 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
13.0745, 49.9401 which is equivalent to:
RA(J2000) = 00h 52m 17.88s
Dec(J2000) = +49d 56' 24.5"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 43 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.42 x
10^21 cm^-2, Kalberla et al. 2005), with an excess column of 2.1
(+1.91/-1.68) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 1.75e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 77 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 00:52:17.84 = 13.07433
DEC(J2000) = +49:56:23.1 = 49.93974
with a 90%-confidence error radius of about 0.61 arc sec. This position is 1.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.26 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.16.
Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta 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 13531
Subject
GRB120729A - Faulkes Telescope North Optical Afterglow Candidate
Date
2012-07-29T11:40:07Z (13 years ago)
From
Francisco Virgili at Liverpool John Moores U <fjv@astro.livjm.ac.uk>
F.J. Virgili (LJMU), J. Japelj (U. Ljubljana), C.G. Mundell (LJMU), A. Melandri (INAF-OAB) report:
"The 2-m Faulkes Telescope North robotically followed up GRB120729A
(SWIFT trigger 529095, Ukwatta et al. GCN 15530 ) 4.60 min after the GRB trigger time.
The automatic "detection mode" procedure LT-TRAP (Guidorzi et al. 2006) detected a variable uncatalogued afterglow
candidate consistent with the UVOT detection and within the XRT/UVOT and error circles at:
RA 00 52 17.82
DEC 49 56 23 (J2000)
with magnitude R = 16.4 mag (vs USNOB1) 4.60 min after the burst.
Observations are ongoing.
GCN Circular 13532
Subject
GRB 120729A Gemini-N redshift
Date
2012-07-29T13:16:08Z (13 years ago)
From
Nial Tanvir at U.Leicester <nrt3@star.le.ac.uk>
N. R. Tanvir (U. Leicester) and J. Ball (Gemini) report on behalf of a
larger collaboration:
We observed the afterglow of GRB 120729A (Ukwatta et al. GCN 13530)
using the GMOS-N spectrograph on Gemini-North.
Observations began at 2012-7-29 12:11 UT, about 75 mins post-burst.
The spectrum reveals strong absorption lines of MgI, MgII, FeII, MnII.
A provisional reduction gives a redshift of z=0.80, which we believe is most
likely the redshift of this burst.
GCN Circular 13534
Subject
GRB 120729A: Enhanced Swift-XRT position
Date
2012-07-29T15:41:52Z (13 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.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 1033 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 120729A, 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 = 13.07446, +49.93967 which is equivalent
to:
RA (J2000): 00h 52m 17.87s
Dec (J2000): +49d 56' 22.8"
with an uncertainty of 1.8 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 13536
Subject
GRB 120729A, Swift-BAT refined analysis
Date
2012-07-29T16:17:26Z (13 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA),C. B. Markwardt (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC),
T. N. Ukwatta (MSU)(i.e. the Swift-BAT team):
Using the data set from T-61 to T+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 120729A (trigger #529095)
(Ukwatta, et al., GCN Circ. 13530). The BAT ground-calculated position is
RA, Dec = 13.078, 49.936 deg which is
RA(J2000) = 00h 52m 18.8s
Dec(J2000) = +49d 56' 08.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 76%.
The mask-weighted light curve shows a single FRED peak with a rise of ~20 secs
and a fall of ~100 seconds. There are no significant subsidiary peaks.
T90 (15-350 keV) is 71.5 +- 17.5 sec (estimated error including systematics).
The time-averaged spectrum from T-3.08 to T+101.94 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.62 +- 0.08. The fluence in the 15-150 keV band is 2.4 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.03 sec in the 15-150 keV band
is 2.9 +- 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/529095/BA/
GCN Circular 13537
Subject
GRB 120729A: Xinglong TNT optical upper limit
Date
2012-07-29T17:51:13Z (13 years ago)
From
L.P. Xin at NAOC <xlp@bao.ac.cn>
L.P. Xin, J. Y. Wei, Y.L. Qiu, J. Wang, J.S. Deng,
C. Wu, X. H. Han on behalf of EAFON report:
We began to observe GRB 120729A (Ukwatta et al. GCN Circ. 13530 )
with Xinglong TNT telescope at 15:23:22.671 (UT), 4.45 hour after
the burst. A series of R-band images were obtained.
Preliminary analysis shows that no any source was found
at the location of optical counterpart (Ukwatta et al. GCN Circ. 13530;
Virgili et al. GCN 13531), down to 3 sigma upper limit of R~19.5 mag,
relatively to the USNO B1.0 R2 mag, at the mean time of 4.8 hour after
the burst.
This message may be cited.
Thanks to the help of TNT observation assistant for this work.
For more information about Xinglong GRBs Follow-up
observations, please visit the website:
http://www.xinglong-naoc.org/grb/
GCN Circular 13539
Subject
GRB 120729A: Swift/UVOT Detection
Date
2012-07-29T18:39:35Z (13 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (MSSL-UCL) and T. N. Ukwatta (MSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120729A
77 s after the BAT trigger (Ukwatta et al., GCN Circ. 13530).
A source consistent with the XRT position (Beardmore et al., GCN Circ. 13534)
and the optical position reported by FTN (Virgili et al., GCN Circ. 13531) is
detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 00:52:17.83 = 13.07431 (deg.)
Dec (J2000) = +49:56:23.1 = 49.93974 (deg.)
with an estimated uncertainty of 0.50 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 77 227 147 15.33 +/- 0.02
v 620 640 20 15.92 +/- 0.15
b 545 564 20 16.56 +/- 0.12
u 289 539 246 15.78 +/- 0.04
w1 4113 4313 197 18.49 +/- 0.16
m2 3908 4108 197 18.91 +/- 0.25
w2 595 615 20 17.57 +/- 0.32
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.16 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 13541
Subject
GRB 120729A: Swift-XRT refined Analysis
Date
2012-07-29T23:17:06Z (13 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
A. Maselli (INAF-IASFPA), D.N. Burrows (PSU), J.A. Kennea (PSU), M.C.
Stroh (PSU), O.M. Littlejohns (U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), V. Mangano (INAF-IASFPA), A.
Melandri (INAF-OAB) and T.N. Ukwatta report on behalf of the Swift-XRT
team:
We have analysed 13 ks of XRT data for GRB 120729A (Ukwatta et al. GCN
Circ. 13530), from 74 s to 29.5 ks after the BAT trigger. The data
comprise 170 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 13534).
The light curve can be modelled with an initial power-law decay with an
index of alpha=1.115 (+0.023, -0.022), followed by a break at T+8203 s
to an alpha of 2.9 (+/-0.4).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.56 (+/-0.10). The
best-fitting absorption column is 1.9 (+/-0.3) x 10^21 cm^-2, in
excess of the Galactic value of 1.4 x 10^21 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 1.87 (+0.15, -0.14)
and a best-fitting absorption column of 2.1 (+0.5, -0.4) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.2 x 10^-11 (5.8 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.1 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 1.4 x 10^21 cm^-2
Excess significance: 2.5 sigma
Photon index: 1.87 (+0.15, -0.14)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00529095.
This circular is an official product of the Swift-XRT team.
GCN Circular 13543
Subject
T100 observations of GRB 120729A
Date
2012-07-30T10:54:36Z (13 years ago)
From
Tolga Guver at UA <tolga@physics.arizona.edu>
Guver, T. (Sabanci Univ.), Sonbas, E. (GSFC, Adiyaman Univ.), S.
Kaynar (Akdeniz Univ.), O. Onal (Istanbul Univ.), S. Tuncel Guctekin
(Istanbul Univ.),
Gogus, E. (Sabanci Univ.), S. Ak (Istanbul Univ.), Z. Eker (TUG) on
behalf of a larger collaboration.
We observed the field of GRB 120729A (Ukwatta et al., GCN #13530)
with the 1.0 meter T100 telescope (TUBITAK National Observatory,
Antalya - Turkey), starting at 2012-07-29, 19:43:07 UT ( ~9 hours
after the trigger). We obtained 4 x 300 s exposures with R filter under poor
weather conditions (seeing 2.4").
Similar to the report by Xin et al. (GCN #13537) we do not detect an
optical afterglow at the UVOT error circle reported by Ukwatta et al.
(GCN #13530) in the combined R band image. We determine the 4-sigma
detection limit of our R band image to be 20.04 mag, (calibrated to R2
of USNO-B1).
We are grateful to the TUBITAK National Observatory staff for promptly
scheduling the observations and their technical support.
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GCN Circular 13544
Subject
GRB 120729A: UKIRT Observation
Date
2012-07-30T14:05:05Z (13 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
Myungshin Im and Jueun Hong (CEOU/Seoul National Univ.) on behalf of
a larger collaboration.
We observed GRB 120729A (Ukwatta et al., GCN 13530) in
ZYJHK using WFCAM on UKIRT.
The observation started at 2012-07-29 13:01:41 UT,
or about 2.09 hours after the BAT alert.
In all of the ZYJHK images, we identify the afterglow
(H ~ 18.0 AB mag) which was reported earlier by several groups
(Virgili et al. GCN 13531; Oates et al. GCN 13539).
We also confirm fading of the object from another set of
WFCAM data we took about 3 hours later.
Further observations are planned.
GCN Circular 13545
Subject
GRB 120729A: Early RAPTOR Observations
Date
2012-07-30T21:15:47Z (13 years ago)
From
James Wren at LANL <jwren@nis.lanl.gov>
J. Wren, P. Wozniak, H. Davis, and W.T. Vestrand
of Los Alamos National Laboratory report:
The RAPTOR network of robotic optical telescopes responded to Swift trigger
529095 (Ukwatta et al., GCN 13530). Observations began at 10:56:42.0 UT,
27.9 s after the initial Swift trigger and before the end of the gamma-ray
emitting interval. Our observations were performed under clear skies with
morning twilight just beginning. We clearly detect the optical counterpart
(Ukwatta et al., GCN 13530, and Virgili et al., GCN 13531). We initially
detect the counterpart at a magnitude of 13.2, and at about T+50 s
it begins to fade steadily at a power law index of about 0.9 for the next
1000 seconds. Our unfiltered magnitudes are calibrated against the USNO-B1
R-band. The following table gives a sample of some of our observations.
The image mid-points are given relative to the initial BAT trigger time.
t-mid(s) exp(s) mag error
--------------------------------------
30.4 5 13.21 0.01
39.8 5 13.28 0.01
49.2 5 13.35 0.01
118.4 10 14.18 0.01
248.8 10 14.97 0.02
391.8 30 15.36 0.02
817.0 30 16.11 0.06
1071.4 30 16.46 0.11
GCN Circular 13546
Subject
Virtual Telescope observations of GRB 120729A
Date
2012-07-30T21:58:10Z (13 years ago)
From
Gianluca Masi at Bellatrix Astronomical Obs <gianluca@bellatrixobservatory.org>
G. Masi (Ceccano, Italy) and F. Nocentini (Frosinone, Italy) report:
On July 29.9496 2012 UT, we imaged the field around the position provided
by Ukwatta et al. (GCN 13530) with the 0.43m-f/6.8 unit part of the Virtual
Telescope robotic facility in Italy.
4, 300 seconds unfiltered CCD images were coadded and compared with a R plate
from the DSS2: they do NOT show any obvious afterglow, down to R = 20.0 (based
on USNO B1.0). The position of the afterglow mentioned on GCN 13530 is close to
a R=19.2 source (with end figures 18.28s and 23.2", J2000.0).
GCN Circular 13547
Subject
GRB 120729A: EVLA Observations
Date
2012-07-31T02:39:04Z (13 years ago)
From
Tanmoy Laskar at Harvard U <tanmoylaskar@gmail.com>
T. Laskar, A. Zauderer and E. Berger (Harvard) report:
"We observed the position of GRB 120729A (Ukwatta et al. GCN 13530) with
the EVLA beginning 2012 July 30.3 UT (0.84 days after the burst). No
significant radio emission is detected at the enhanced Swift-XRT position
(Beardmore et al. GCN 13534), the UVOT position (Oates et al. GCN 13539) or
optical position (Virgili et al. GCN 13531) to three-sigma upper limits
of 39 uJy and 58 uJy, at 5.8 and 21.8 GHz, respectively."
GCN Circular 13548
Subject
GRB 120729A: RTT150 optical observations
Date
2012-07-31T10:28:25Z (13 years ago)
From
Rodion Burenin at IKI, Moscow <rodion@hea.iki.rssi.ru>
I. Khamitov (TUG), E.Beklen (SD Uni.),
Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Bikmaev, N. Sakhibullin (Kazan Federal University)
report:
We observed the field of the Swift-BAT GRB 120729A (Ukwatta et al. GCN
15530 ) with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe,
TUBITAK National Observatory, Turkey), starting at 30 Jul, 01:26 UT,
i.e. approximately 14.5 hours after the burst, using TFOSC instrument.
We made 6x300s exposures in R-band under good atmospheric conditions
(1.4 arcsec seeing) at the beginning of morning twilight without
moonlight. We do not detect any new source on combined image at the
position of OT (Virgili et al., GCN13531; Oates and Ukwatta,
GCN13539). Using USNO-B1 stars we estimated the limiting magnitude of
combined image as m_R =~ 23.5.
A small field around of the OT position can be found at:
http://hea.iki.rssi.ru/grb/120729a/indexeng.html
GCN Circular 13550
Subject
GRB 120729A: Optical observations from OSN, BOOTES1/2 and IAC80
Date
2012-07-31T10:53:25Z (13 years ago)
From
Javier Gorosabel at IAA-CSIC <jgu@iaa.es>
J. Gorosabel (IAA-CSIC), M. Jelinek (IAA-CSIC), Ch. Wang (Yunnan
Observatory, China), C. Zurita (IAC), A. Sota (OSN, IAA-CSIC), J.C. Tello
(IAA-CSIC), R. Sanchez-Ramirez (IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC),
report on behalf of a larger collaboration:
"We carried out BRI-band observations of the GRB 120729A (Ukwatta et al.
GCN Circ. 13530) optical afterglow (Virgili et al. GCN Circ. 13531; Oates
et al. GCN Circ. 13539) as follows:
Telescope Obs.Date(UT) Time post GRB(hr) Exp.Time(s) Mag.(Vega)
------------------------------------------------------------------------
0.3m Bootes-1B 29.879537-30.022106 10.17-13.58 326x30 R > 19.0
0.6m Bootes-2 30.007951-30.042095 13.25-14.07 50x60 R > 19.4
1.5m OSN 30.077613-30.163785 14.93-16.99 18x300 R > 22.1
1.5m OSN 30.096195-30.099667 15.37-15.45 1x300 B > 21.5
0.82m IAC80 30.120174-30.205093 15.95-17.98 22x300 I = 21.9+/-0.3
The calibration was based on the USNO B1.0 catalogue."
GCN Circular 13551
Subject
GRB 120729A: break in the optical light curve
Date
2012-07-31T11:06:32Z (13 years ago)
From
Andrea Melandri at INAF-OAB <andrea.melandri@brera.inaf.it>
P. D'Avanzo, A. Melandri (INAF-OAB), I. Steele, C.G. Mundell (LJMU),
E. Palazzi (INAF-IASFBo) report, on behalf of larger collaborations:
We observed the optical counterpart of GRB 120729A (Ukwatta et al.,
GCN 13530; Virgili et al., GCN 13531; Oates et al., GCN 13539; Wren et
al., GCN 13545) with the 2-m Faulkes Telescope North (FTN), the 2-m
Liverpool Telescope (LT) and with the Italian 3.6m Telescopio
Nazionale Galileo (TNG). Early time observations were carried out from
4.6 min to 2.1 hours after the burst with the FTN, while a later
observation epoch was taken at a mid time of about 14.5 hours after
the burst with the LT and the TNG.
From a preliminary analysis the overall R-band light curve can be
described by an initial power-law decay with an index of alpha1=1.0
that breaks around t-t0=6000 s to a steeper decay with alpha2=1.8. The
early time decay is consistent with the report of Wren et al. (GCN
13545).
The last detection was obtained with the TNG at a level of R ~ 23.3
mag (15.1 hours post burst) consistent with the marginal detections
obtained with LT SDSS-r filter (image acquired ~13.6 hours after the
burst). These late time values fall slightly below the best broken
power-law fit described above, suggesting that the post-break decay
index might be steeper than 2.
We note that the reported X-ray afterglow decay (Maselli et al., GCN
13541) shows a similar behaviour and that this may be indicative of an
achromatic break in the afterglow light curve.
We thank the TNG staff for performing the ToO observations, in
particular Massimo Cecconi.
GCN Circular 13554
Subject
GRB 120729A: JCMT SCUBA-2 sub-mm observation
Date
2012-07-31T22:33:41Z (13 years ago)
From
Ian Smith at Rice U <ian@spacsun.rice.edu>
I.A. Smith (Rice U.), R.P.J. Tilanus (JAC), N.R. Tanvir (U. of Leicester),
D.A. Frail (NRAO) report:
We observed the location of GRB 120729A (Ukwatta et al., GCN Circ.
13530) using the SCUBA-2 sub-millimeter continuum camera on the James
Clerk Maxwell Telescope. The observation started at 12:14 UT on
2012-07-29, corresponding to 78 minutes after the burst trigger.
Exposures totaling 3.1 hours were made in reasonable weather conditions.
No source was detected, with a preliminary RMS of 1.8 mJy/beam at
850 microns.
We thank Jeff Cox and Ruud Visser for their prompt support of these
observations.
GCN Circular 13560
Subject
GRB 120729A: Fermi GBM observation
Date
2012-08-02T12:40:37Z (13 years ago)
From
Arne Rau at MPE <arau@mpe.mpg.de>
Arne Rau (MPE) reports on behalf of the Fermi GBM Team:
"At 10:56:12.67 UT on 29 July 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 120729A (trigger 365252175 / 120729456)
which was also detected by the Swift/BAT (Ukwatta et al. 2012, GCN 13530).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 83 degrees.
The GBM light curve shows a single pulse with a duration (T90) of about 25 s (50-300 keV).
The time-averaged spectrum from T0-3.6 s to T0+17.9 s is
best fit by a simple power law function with index -1.49 +/- 0.05.
The event fluence (10-1000 keV) in this time interval is
(5.1 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.2 s in the 10-1000 keV band
is 5.2 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 18184
Subject
GRB 120729A: KAIT Optical Observations
Date
2015-08-20T18:56:44Z (10 years ago)
From
Xiang-Gao Wang at GuangXi U <wangxg@gxu.edu.cn>
Xianggao Wang (UC Berkeley, GXU, UNLV), WeiKang Zheng,
Alexei V. Filippenko (UC Berkeley), and S. Bradley Cenko
(GSFC) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 120729A (Ukwatta et al.,
GCN 13530) starting at 10:58:16 UT, 122 s after the burst.
Observations were performed with an automatic sequence in the
clear (roughly R), V, and I filters, and the exposure time was
20 s per image. The bright optical afterglow (Ukwatta et al. GCN 13530,
Virgili et al. GCN 13531, Oates et al. GCN 13539, Im et al. 13544,
Wren et al. 13545, Khamitov et al. GCN 13548, Gorosabel GCN 13550,
D'Avanzo et al. GCN 13551, Smith et al. GCN 13554) was detected
in all three filters. Useful observations lasted for about 2.4 hours.
Preliminary analysis shows that the afterglow decays with a single
power (with alpha = -0.87) beyond 1000 s after the burst. A light
curve is posted at
http://astro.berkeley.edu/~zwk/grb/GRB120729A/GRB120729A_kait.png .