GRB 110402A
GCN Circular 11892
Subject
Redshift of GRB 110402A theoretically estimated (revised)
Date
2011-04-06T23:11:23Z (16 years ago)
From
Remo Rufinni at ICRA <ruffini@icra.it>
R. Ruffini, L. Izzo, A.V. Penacchioni, C.L. Bianco (ICRANet, ICRA and Rome University "La Sapienza") report:
A more accurate evaluation of GRB 110402A rebinned data leads to an estimate of the redshift z between 0.7 and 1.0.
GCN Circular 11889
Subject
GRB 110402A: fading optical afterglow
Date
2011-04-06T17:50:56Z (16 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Rumyantsev (CrAO), A. Pozanenko (IKI), A. Volnova (SAI MSU) on behalf of
larger GRB follow up collaboration report:
We observed the field of GRB 110402A (Ukwatta et al. GCN 11857) with Shajn
telescope of CrAO observatory on Apr. 3 between (UT) 18:41 and 19:59 under
seeing of about 2.6 arsces. We took several frames with exposure of 60s in
R-band. On a stacked image we detected the optical counterpart (Mundell et
al. GCN 11858, Leloudas et al. GCN 11859). The counterpart has coordinates
(J2000) RA = 13h 09m 36.63s, Dec = +61d 15' 09.5'' with uncertainty of 0.1"
in both coordinates which are fully compatible with initial counterpart
coordinates (Mundell et al. GCN 11858). The photometry is based on the USNO
B1.0 star 1512-0199231 (13 09 43.16 +61 14 38.5) assuming R=16.71.
T0+ Filter, Exposure, mag. uplim (3 sigma)
(mid, d) (s)
1.79672 R 73x60 23.11+/-0.12 24.4
GCN Circular 11888
Subject
Redshift of GRB 110402A theoretically estimated
Date
2011-04-06T17:12:29Z (16 years ago)
From
Remo Rufinni at ICRA <ruffini@icra.it>
R. Ruffini, L. Izzo, A.V. Penacchioni, C.L. Bianco (ICRANet, ICRA and Rome University "La Sapienza") report:
From theoretical considerations on the transparency of the P-GRB (between t0 and t0+6 s), we infer for GRB 110402A a redshift z between 2.02 and 2.48. We strongly encourage a spectroscopic identification of the redshift.
GCN Circular 11887
Subject
GRB 110402A: Suzaku WAM observation of the prompt emission
Date
2011-04-06T13:18:47Z (16 years ago)
From
Makoto Tashiro at Saitama U/Swift <tashiro@phy.saitama-u.ac.jp>
T. Yasuda, Y. Terada, M. Tashiro, W. Iwakiri, K. Takahara (Saitama U.),
T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.),
N. Vasquez (Tokyo Tech.) K. Yamaoka (Aoyama Gakuin U.), S. Sugita
(Nagoya U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA),
Y. E. Nakagawa, T. Tamagawa (RIKEN), N. Ohmori, M. Yamauchi (Univ. of
Miyazaki), Y. Urata, P. Tsai (NCU), K. Nakazawa, K. Makishima (Univ. of
Tokyo), on behalf of the Suzaku WAM team, report:
The GRB 110402A (Swift/BAT trigger #450545; Ukwatta et al.) triggered
the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range
of 50 keV - 5 MeV at 2011-04-02 00:12:58.49 UT (=T0).
The observed light curve shows a multi-peaked structure starting at
T0-1.5s, ending at T0+83.5s, with a duration (T90) of about 70 seconds.
The fluence in 100 - 1000 keV was 9.1 (+0.9, -0.9) x 10^-6 erg/cm^2.
The 1-s peak flux measured from T0+1s was 5.72 photons/cm^2/s in the
same energy range.
Preliminary result shows that the time-averaged spectrum from T0-1.5 s
to T0+83.5 s is well fitted by a single power-law with a photon index of
1.57 (+0.11, -0.10) (chi^2/d.o.f = 44.73/31).
All the quoted errors are at statistical 90% confidence level, in which
the systematic uncertainties are not included.
The light curves for this burst will be update at:
http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html
GCN Circular 11885
Subject
GRB 110402A: LOAO Optical Observation
Date
2011-04-05T14:06:32Z (16 years ago)
From
Yiseul Jeon at SNU/CEOU <ysjeon@astro.snu.ac.kr>
Yiseul Jeon, Myungshin Im (SNU), and Yuji Urata (NCU)
We observed GRB 110402A (Ukwatta et al. GCN 11857) in R, I, z,
and Y-bands using the 1 meter telescope at Mt. Lemmon, AZ, USA.
The observations started at Arpil 2, 04:18:22UT(245.4 min after the BAT trigger),
with the total integration time in each filter at 3 x 300 sec.
A faint source is identified at the positon reported in Mundell et al. (GCN 11858).
A preliminary analysis shows that the R-band magnitude is R=21.0 +- 0.3,
calibrated using R2 magnitude of USNO-B1 stars in the vicinty.
We thank the LOAO operator, J. Yoon for his assistance for this
observation.
[GCN OPS NOTE(05apr11): This circular was delay in distribution
by ~10 hours waiting for a new accont to be enetered.]
GCN Circular 11879
Subject
GRB 110402A: Konus-Wind spectral lags and detailed energetics
Date
2011-04-04T17:05:29Z (16 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks and D. Svinkin on behalf of the Konus-Wind team,
report:
1. The further analysis of the Konus-Wind detection (GCN 11869)
of GRB 110402A (GCN 11857, 11866) confirms the zero spectral
lag in the initial hard pulse reported with the Swift-BAT data
(Barthelmy and Norris, GCN 11870).
The following lag values between the Konus-Wind light curves
are obtained:
-------------------------------------------------------------
LC1(keV) LC2(keV) Search Interval(s) Scale Lag(ms)
-------------------------------------------------------------
G2(70-300) G1(18-70) -0.512:+0.320 8 ms +3.5 � 12.5
G3(300-1160) G1(18-70) -0.512:+0.280 8 ms +3.2 � 12.3
G3(300-1160) G2(70-300) -0.340:+0.320 4 ms -0.3 � 4.8
-------------------------------------------------------------
The errors are given on 1 sigma level.
2. The total burst fluence S=(1.6 � 0.5)x10-5 erg/cm2 reported
in GCN 11869 is divided between the hard initial pulse and
the softer extended emission as follows:
T0(-0.512 : +2.816) -> S1=(5.7 � 1.9)x10-6 erg/cm2 (initial pulse)
T0(2.816 : +65.792) -> S2=(9.9 � 2.9)x10-6 erg/cm2 (extended emission)
The K-W spectrum of the latter part (measured from T0+8.448s
to T0+65.792s) can be fitted in the 20-5000 keV range
by the simple power law function with the index of (1.81 � 0.13),
chi2 = 93.4/78
The errors are given on 90% confidence level.
All times are given relative to K-W T0=781.989s UT.
GCN Circular 11877
Subject
GRB 110402A: Fermi GBM detection
Date
2011-04-04T16:15:43Z (16 years ago)
From
Narayana Bhat at U Alabama/Huntsville/GBM <Narayana.Bhat@nasa.gov>
P. N. Bhat (UAH)
reports on behalf of the Fermi GBM Team:
"At 00:12:58.54 UT on 02 April 2011, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 110402A (trigger 323395980 / 110402009).
which was also detected by the Swift/BAT (Ukwatta et al. 2011, GCN 11857)
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 134.5 degrees.
The GBM light curve consists of multiple sharp pulses
with a duration (T90) of about 36 s (50-300 keV).
The time-averaged spectrum from T0-2.4 s to T0+59 s is
well fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.29 +/- 0.07 and
the cutoff energy, parameterized as Epeak, is 1025 +/- 409 keV
The event fluence (10-1000 keV) in this time interval is
(1.3 +/- 0.06)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.8 s in the 10-1000 keV band
is 7.82 +/- 0.47 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 11876
Subject
GRB 110402A: optical observations in Mondy
Date
2011-04-04T14:33:37Z (16 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (SAI MSU), A. Pozanenko (IKI), E. Klunko (ISTP) on behalf of
larger GRB follow up collaboration report:
We observed the field of GRB 110402A (Ukwatta et al. GCN 11857) with
AZT-33IK telescope of Sayan observatory (Mondy) on April, 2 between (UT)
13:04:22 - 14:37:38 under moderate weather condition and seeing of about
2". In a stacked image we clearly detect optical counterpart (Mundell et al.
GCN 11858, Leloudas et al. GCN 11859). The position of the counterpart is
(J2000) RA= 13:09:36.42 Dec= +61:15:10.35 with uncertainty of 0,4" in both
coordinates. The position is 1.7" apart from initial position reported by
Mundell et al. (GCN 11858). The photometry is based on the USNO B1 star
1512-0199231 assuming R= 16.71
T0+ Filter, Exposure, OT mag., UpperLimit (3 sigma)
(mid, d) (s)
0.56809 R 5430 21.35 +/- 0.10 22.9
Since the position of counterpart is marginally different from initial
position and the R-magnitude does not change since 251.6 minutes after burst
(see Leloudas et al. GCN 11863) we can suggest that host galaxy dominates in
our observations.
[GCN OPS NOTE(30apr11): Per author's request, Elunko was changed to Klunko.]
GCN Circular 11875
Subject
GRB 110402A afterglow observation
Date
2011-04-04T13:29:54Z (16 years ago)
From
Xavier Bros at Anysllum Obs <anysllum@gmail.com>
X. Bros, Agrupaci=C3=B3 Astron=C3=B2mica de Sabadell, Spain,
has done a positive observation of GRB 110402A afterglow
on three unfiltered images done from ANYSLLUM OBSERVATORY, Ager, Spain
using a Newtonian reflector of 350mm f4.6.
1) exp 180 sec at 0h 52m 12 sec UT of 2011/04/02 (39 minutes 15 sec after SWIFT detection)
2) exp 300 sec at 0h 57m 26 sec UT (44 minutes 29 sec after SWIFT detection)
3) exp 300 sec at 1h 07m 48 sec UT (54 minutes 51 sec after SWIFT detection)
The afterglow is visible in all of these images. Position measured using
UCAC 2 reference stars:
13h 09m 36.57s
+61d 15' 10.2"
Magnitude estimation on the combined add image (180sec+300sec+300sec)
of 20.8CR, (unfiltered) using R reference stars from USNO A2.0 (18.7R,
18.8R, 19.5R).
The image is linked in: http://anysllum.com/GRB%20110402A%20X%20Bros.jpg
[GCN OPS NOTE(04apr11). This circular was delayed in distribution for 15 hours
while an account was set up.]
GCN Circular 11873
Subject
GRB 110402A: MITSuME Okayama and Ishigakijima Optical upper limits
Date
2011-04-03T13:13:07Z (16 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda, (OAO, NAOJ), H. Hanayama (IAO, NAOJ), K. Yanagisawa,
Y. Shimizu, H. Toda (OAO, NAOJ), T. Miyaji J. Watanabe, (IAO, NAOJ),
S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto)
and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 110402A (Ukwatta et al., GCN 11857)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory
and the Murikabushi 1m telescope of Ishigakijima Astronomical
Observatory.
We did not find any new point source within the enhanced XRT error
circle (Beardmore et al., GCNC 11860) in all the three bands. We
could not detect the previously reported afterglow
(Mundell et al., GCN 11858).
Ishigakijima Astronomical Observatory:
The observation started on 2011-04-02 12:18:01 UT, (~12.1 h
after the burst).
T0+[day] MID-UT T-EXP[sec] g' Rc Ic
------------------------------------------------------
0.53014 12:56:21 3540.0 >21.4 >21.4 >20.4
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
Okayama Astrophysical Observatory:
The observation started on 2011-04-02 13:51:58 UT, (13.7 h
after the burst).
Three sigma upper limits of the OT are listed below. We used
SDSS catalog for flux calibration.
T0+[day] MID-UT T-EXP[sec] g' Rc Ic
------------------------------------------------------
0.56634 13:48:29 8400.0 >19.6 >20.0 >19.4
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 11871
Subject
GRB 110402A: Swift/UVOT detection of afterglow candidate
Date
2011-04-03T02:32:55Z (16 years ago)
From
Craig Swenson at PSU/Swift <cswenson@astro.psu.edu>
C. A. Swenson (PSU) and T. N. Ukwatta (MSU)report on behalf
of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 110402A
548 s after the BAT trigger (Ukwatta et al., GCN Circ. 11857).
We find a faint new source consistent with the enhanced XRT position
(Beardmore et al., GCN Circ. 11860).
Preliminary magnitudes and 3-sigma upper limits using the UVOT
photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
---------------------------------------------------------------------
white_FC 548 698 147 >20.5
white 548 24657 1628 20.89 �0.11
v 704 18897 510 >20.1
b 803 24593 1544 20.84 �0.20
u 778 30417 430 >20.6
w1 754 30390 1296 20.39 �0.22
m2 7176 7376 197 >19.7
w2 6767 18791 1112 20.29 �0.20
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 11870
Subject
GRB 110402A: Spectral lag indicates short hard burst
Date
2011-04-03T00:24:08Z (16 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
S.D. Barthelmy (GSFC) and J. Norris (BSU)
report:
For GRB 110402A (Trigger 450545, GCNs 11857 & 11866),
the spectral lag analysis of the Swift-BAT data from T+0.8 sec to T+6.0 sec
(the initial 5 spikes), yields a lag of 3.7 +2.5/-2.9 msec for the
25-50 to 100-300 keV bands using a lightcurve binning of 4 msec.
While the 5.2 sec duration for the 5 spikes is formally beyond
the cononical 2-s boundary in duration for short bursts,
the small lag value favors a short burst identification.
We note that there is on-going, much softer emission from T+5 to T+78 sec,
and lacking sufficient structure to yield a significant lag measurement.
GCN Circular 11869
Subject
Konus-Wind observation of GRB 110402A
Date
2011-04-02T18:09:18Z (16 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The long GRB 110402A, (Swift/BAT trigger=450545:
Ukwatta et al., GCN 11857; Stamatikos et.al, GCN 11866)
triggered Konus-Wind at T0=00781.989s UT (00:13:01.989)
The burst light curve started with a hard multi-peaked pulse
followed, after ~5s, by a softer decaying emission.
The total duration of of the burst is ~70 s.
The emission in the initial hard pulse is seen up to ~5 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB110402_T00781/
As observed by Konus-Wind the burst
had a fluence of (1.6 � 0.5)x10-5 erg/cm2,
and a 16-ms peak flux, measured from T0,
of (2.3 � 0.9)x10-5 erg/cm2/s
(both in the 20 keV - 5 MeV energy range).
The time-integrated spectrum of the burst
(from T0 to T0+65.792 s) is best fitted
in the 20 keV - 5 MeV range by a simple
power law function with the photon index
= (1.67 � 0.09), chi2 = 86.6/78 dof.
The spectrum at the maximum count rate
(measured from T0 to T0+0.256 s) is best fitted
in the 20 keV - 5 MeV range by a power law
with exponential cutoff model, for which
alpha = -1.03 (-0.14, +0.16),
and Ep = 1395(-604, +1835) keV,
chi2 = 23.9/21 dof.
All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.
GCN Circular 11868
Subject
GRB 110402A: Konkoly observations
Date
2011-04-02T15:46:10Z (16 years ago)
From
Janos Kelemen at Konkoly Obs/Hungary <kelemen@konkoly.hu>
J. Kelemen,(Konkoly Obs.)
on behalf of the GRB OT observing program at the Konkoly Observatory.
We observed the field of GRB 110402A using the enhanced Swift-XRT position
A.P. Beardmore et al. (GCN 11860) with a 60/90 cm Schmidt telescope located at
the Mountain Station of the Konkoly Observatory. Within the XRT error circle
we found an OT candidate at the position:
RA(2000) 13h 09m 36.64s
Dec(2000) +61d 15' 09.7"
With an uncertainty of 0.15 arcsec.
For the photometry of the source on the coadded frames (total exp time 900
sec) nearby stars of the UCAC3 catalogue were used.
Time from
the trigger magnitude Band
----------------------------------------
9523 sec 21.0 +/- 0.2 R
Further observations planned.
GCN Circular 11866
Subject
GRB 110402A: Swift-BAT refined analysis
Date
2011-04-02T13:59:12Z (16 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 110402A (trigger #450545)
(Ukwatta, et al., GCN Circ. 11857). The BAT ground-calculated position is
RA, Dec = 197.432, 61.247 deg, which is
RA(J2000) = 13h 09m 43.7s
Dec(J2000) = +61d 14' 49.6"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 10%.
The mask-weighted light curve shows 5 spikes (each with a duration less than 0.5 sec)
with the first at ~T+1.5 sec and the last at ~T+6 sec. These are followed
by softer emission out to ~T+90 sec. T90 (15-350 keV) is 60.9 +- 6.9 sec
(estimated error including systematics).
The time-averaged spectrum from T-0.4 to T+69.7 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.59 +- 0.17. The fluence in the 15-150 keV band is 3.4 +- 0.4 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.18 sec in the 15-150 keV band
is 4.1 +- 0.7 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/450545/BA/
GCN Circular 11865
Subject
GRB 110402A: Swift-XRT refined Analysis
Date
2011-04-02T11:17:47Z (16 years ago)
From
Claudio Pagani at U of Leicester <cp232@star.le.ac.uk>
C. Pagani (U. Leicester) and T. N. Ukwatta (MSU) report on behalf of
the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 110402A (Ukwatta et al.
GCN Circ. 11857), from 552 s to 24.7 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. The enhanced XRT
position for this burst was given by Beardmore et al. (GCN. Circ
11860).
The late-time light curve (from T0+6.4 ks) can be modelled with a
power-law decay with a decay index of alpha=1.3 (+/-0.4).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.31 (+0.25, -0.27). The
best-fitting absorption column is 10.0 (+2.9, -5.6) x 10^20 cm^-2, in
excess of the Galactic value of 1.6 x 10^20 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 3.3 x 10^-11 (4.8 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 10.0 (+2.9, -5.6) x 10^20 cm^-2
Galactic foreground: 1.6 x 10^20 cm^-2
Excess significance: 2.9 sigma
Photon index: 2.31 (+0.25, -0.27)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00450545.
This circular is an official product of the Swift-XRT team.
GCN Circular 11864
Subject
GRB 110402A: early optical limit by "Pi of the Sky"
Date
2011-04-02T10:16:16Z (16 years ago)
From
Grzegorz Wrochna at Soltan Inst.for Nuclear Studies <wrochna@fuw.edu.pl>
M.Sokolowski,T.Batsch,A.Majcher,A.Majczyna,K.Nawrocki,J.Uzycki,G.Wrochna (IPJ, Swierk),
M.Cwiok,W.Dominik,L.W.Piotrowski,A.F.Zarnecki (University of Warsaw),
K.Malek,L.Mankiewicz,R.Opiela,M.Siudek,V.Repei (CFT PAN),
G.Kasprowicz,M.Zaremba (Warsaw University of Technology),
from the "Pi of the Sky" collaboration (http://grb.fuw.edu.pl ).
M. Jelinek and A. J.Castro-Tirado (IAA-CSIC Granada) on behalf of a larger collaboration.
The wide field "Pi of the Sky North" apparatus installed in the BOOTES-1
station at ESAt/INTA-CEDEA in Mazagon (Huelva, Spain;
http://grb.fuw.edu.pl/pi/index.html#piinta_site.htm )
observed field of GRB 110402A at the time of Fermi-GMB and Swift-BAT triggers.
No new source brighter than 11 mag has been identified on 10s exposures:
t_start - t0 start (UT) end (UT) 3-sigma limit
-6 00:12:52 00:13:02 11.0
+7 00:13:05 00:13:15 11.0
where limit is based on the reference star magnitudo in V filter.
GCN Circular 11863
Subject
GRB 110402A: further NOT observations
Date
2011-04-02T08:44:59Z (16 years ago)
From
Giorgos Leloudas at Dark Cosmology Centre <giorgos@dark-cosmology.dk>
G. Leloudas (DARK/NBI), D. Xu (WIS), J. Hjorth (DARK/NBI), P.
Jakobsson (U. Iceland), M. Bayliss (U. Chicago/KICP), report on behalf
of a larger collaboration:
We re-observed the field of GRB 110402A (Ukwatta et al., GCN 11857)
with the Nordic Optical Telescope (La Palma, Spain) equipped with
MOSCA. We obtained two more 600 s R-band exposures starting at 02:38
UT and 04:24 UT.
In the table below we summarize all photometry obtained at the NOT,
where we have also re-calibrated the photometry in Leloudas et al.
(GCN 11859) based on several USNO B1.0 stars in the field:
t_start (min) R (mag)
83.1 21.15 +- 0.06
96.6 21.10 +- 0.08
145.5 21.10 +- 0.06
251.6 21.50 +- 0.07
The source has faded significantly between our last two observations
confirming its transient nature.
GCN Circular 11861
Subject
GRB 110402A: PAIRITEL NIR Upper Limits
Date
2011-04-02T06:02:36Z (16 years ago)
From
Adam Morgan at U.C. Berkeley <qmorgan@gmail.com>
A. N. Morgan, C. R. Klein, and J. S. Bloom (UC Berkeley) report:
We observed the field of GRB 110402A (Ukwatta et al., GCN 11857) with
the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began
at 2011-04-02 04:28:41 UT, ~4.26 hours after the Swift Trigger. In
mosaics (effective exposure time of 0.63 hours) taken simultaneously
in the J and H filters, we do not detect any source at the optical
afterglow location (Mundell et al., GCN 11858, Leloudas et al., GCN
11859). Our preliminary Ks band reduction is corrupted.
The preliminary photometry yields:
post burst
t_mid (hr) exp.(hr) filt U. Limit (3 sig)
4.77 0.63 J > 19.1
4.77 0.63 H > 18.2
Further observations are ongoing to obtain a deeper limit. All
magnitudes are given in the Vega system, calibrated to 2MASS. No
correction for Galactic extinction has been made to the above reported
values.
GCN Circular 11860
Subject
GRB 110402A: Enhanced Swift-XRT position
Date
2011-04-02T05:37:05Z (16 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 1602 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 110402A, 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 = 197.40226, +61.25285 which is equivalent
to:
RA (J2000): 13h 09m 36.54s
Dec (J2000): +61d 15' 10.3"
with an uncertainty of 2.0 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 11859
Subject
GRB 110402A: NOT afterglow confirmation
Date
2011-04-02T02:51:06Z (16 years ago)
From
Giorgos Leloudas at Dark Cosmology Centre <giorgos@dark-cosmology.dk>
G. Leloudas (DARK/NBI), D. Xu (WIS), P. Jakobsson (U. Iceland), M.
Bayliss (U. Chicago/KICP), report on behalf of a larger collaboration:
We observed the field of GRB 110402A (Ukwatta et al., GCN 11857) with
the Nordic Optical Telescope (La Palma, Spain) equipped with MOSCA.
Observations started at 01:26:09.0 UT (73.9 mins after the GRB).
We obtained 3x300 s in the R filter.
We detect a transient within the XRT error circle consistent with the
position reported in Mundell et al. (GCN 11858).
Between the 1st and 3rd exposures, the optical transient shows
marginal decay from 21.10 +- 0.02 to 21.17 +- 0.04 mag, calibrated
with respect to the USNO
B1 star 1512-0199231 (R1= 16.71 mag).
Since the object has also faded by 0.3 mag with respect to GCN 11858,
we suggest that this is the afterglow of GRB 110402A.
GCN Circular 11858
Subject
GRB 110402A: Liverpool Telescope Observations
Date
2011-04-02T02:12:26Z (16 years ago)
From
Carole Mundell at ARI, JMU,Liverpool <cgm@astro.livjm.ac.uk>
C.G. Mundell (Liverpool), A. Melandri (INAF-OAB) and N. Tanvir (Leicester) report on behalf of a larger collaboration:
"The 2-m Liverpool Telescope robotically followed up GRB110402
(SWIFT trigger 450545; Ukwatta et al. GCN 11857) 14.85 min after the GRB
trigger time.
We identify a faint source detected within the XRT error circle in R, i'
and z' band images at:
RA = 13:09:36.64 Dec = +61:15:09.7 +/-0.1" (J2000)
with R = 20.8 (+/-0.1) mag at t=28.0 min
I = 20.75 (+/-0.17) mag at t= 33.0 min (vs USNOB1)
Fading is yet to be confirmed.
This message may be cited"
GCN Circular 11857
Subject
GRB 110402A: Swift detection of a burst
Date
2011-04-02T00:48:01Z (16 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC),
J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC),
A. Melandri (INAF-OAB), C. Pagani (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL),
C. J. Saxton (UCL-MSSL), M. C. Stroh (PSU), C. A. Swenson (PSU) and
E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:
At 00:12:57 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 110402A (trigger=450545). Swift slewed to the burst at T+9 min.
The BAT on-board calculated location is RA, Dec 197.419, +61.242 which is
RA(J2000) = 13h 09m 41s
Dec(J2000) = +61d 14' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed multiple short spikes
with a total duration of about 40 sec. The peak count rate
was ~9000 counts/sec (15-350 keV), at ~5 sec after the trigger.
The XRT began observing the field at 00:22:01.5 UT, 544.3 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 197.4014,
61.2527 which is equivalent to:
RA(J2000) = 13h 09m 36.33s
Dec(J2000) = +61d 15' 09.6"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 49 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 consistent with the Galactic value of 1.62
x 10^20 cm^-2 (Kalberla et al. 2005).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 547 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
0.02.
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.)