GRB 110503A
GCN Circular 11991
Subject
GRB 110503A: Swift detection of a burst with a bright optical counterpart
Date
2011-05-03T17:59:20Z (14 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
M. Stamatikos (OSU/NASA/GSFC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
D. N. Burrows (PSU), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC),
J. M. Gelbord (PSU), S. T. Holland (CRESST/USRA/GSFC),
J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA),
N. P. M. Kuin (UCL-MSSL), O. M. Littlejohns (U Leicester),
V. Mangano (INAF-IASFPA), C. B. Markwardt (NASA/GSFC),
F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB),
P. T. O\'Brien (U Leicester), K. L. Page (U Leicester),
D. M. Palmer (LANL), P. Romano (INAF-IASFPA), M. H. Siegel (PSU),
R. L. C. Starling (U Leicester), C. A. Swenson (PSU),
E. Troja (NASA/GSFC/ORAU) and T. N. Ukwatta (MSU) report on behalf of
the Swift Team:
At 17:35:45 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 110503A (trigger=452685). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 132.800, +52.216 which is
RA(J2000) = 08h 51m 12s
Dec(J2000) = +52d 12' 56"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single structure
with a duration of about 10 sec. The peak count rate
was ~17,000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 17:37:19.2 UT, 93.6 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 132.7778, +52.2067 which is equivalent to:
RA(J2000) = 08h 51m 06.67s
Dec(J2000) = +52d 12' 24.1"
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This
location is 58 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.
UVOT took a finding chart exposure of nominal 150.000 seconds with the White
filter starting 212 seconds after the BAT trigger. There is a candidate
afterglow in the list of sources generated on-board at
RA(J2000) = 08:51:06.24 = 132.77598
DEC(J2000) = +52:12:27.5 = 52.20764
with a 90%-confidence error radius of about 1.10 arc sec. This position is 5.2
arc sec. from the center of the XRT error circle. The estimated magnitude is
15.75. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.02.
Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 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 11992
Subject
GRB 110503A: Enhanced Swift-XRT position
Date
2011-05-03T21:46:18Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester)
report on behalf of the Swift-XRT team.
Using 995 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 110503A, 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 = 132.77598, +52.20753 which is equivalent
to:
RA (J2000): 08h 51m 6.24s
Dec (J2000): +52d 12' 27.1"
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 11993
Subject
GRB 110503A: Redshift from 10.4m GTC
Date
2011-05-03T22:50:27Z (14 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (DARK/NBI), A.J. Castro-Tirado, J.C. Tello
(IAA-CSIC), A. Cabrera Lavers, D. Reverte (GTC) report on behalf of a
larger
collaboration:
We have observed the afterglow of GRB 110503A (Stamatikos et al.
GCNC11991) using OSIRIS at the 10.4m GTC telescope (La Palma, Spain).
Observations consisted on 2x900s using the R500B grating, starting at
21:36UT (4.0h after the burst). In a preliminary analysis, using archival
calibrations, we detect a high signal to noise ratio continuum with
absorption features that include SiIV, SiII, CIV, FeII, AlII, AlIII, ZnII,
MgII and MgI at a common redshift of z=1.613, which we identify as the
redshift of the afterglow.
GCN Circular 11994
Subject
GRB 110503A: NOT afterglow photometry
Date
2011-05-03T22:52:47Z (14 years ago)
From
Giorgos Leloudas at Dark Cosmology Centre <giorgos@dark-cosmology.dk>
G. Leloudas (DARK/NBI), D. Xu (WIS), A. de Ugarte Postigo (DARK/NBI), P. Jakobsson (U. Iceland), L. Guaita, A. Sandberg (OKC/Stockholm), report on behalf of a larger collaboration.
We used the Nordic Optical Telescope (La Palma, Spain) equipped with MOSCA to observe GRB 110503A (Stamatikos et al., GCN 11991).
Observations were conducted in the UBVRI filters starting at 21:18 UT (222.3 min after the BAT trigger). The exposure times were 600, 300, 300, 300 and 400 s respectively.
The afterglow is well detected in all filters at a position consistent with the UVOT observations (Stamatikos et al., GCN 11991).
Photometry, using stars 1422-0232263 and 1422-0232264 of the USNO B1.0 catalog as comparison, gives B ~ 19.7 and R ~ 19.3.
GCN Circular 11995
Subject
GRB 110503A: Swift-BAT refined analysis
Date
2011-05-03T23:14:58Z (14 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. Sakamoto (GSFC/UMBC), 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), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-124 to T+689 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 110503A (trigger #452685)
(Stamatikos, et al., GCN Circ. 11991). The BAT ground-calculated position is
RA, Dec = 132.799, 52.211 deg which is
RA(J2000) = 08h 51m 11.8s
Dec(J2000) = +52d 12' 40.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 11%.
The mask-weighted light curve shows a single FRED-like peak starting
at ~T-4 sec, peaking at ~T+0.2 sec, and returning to background around
T+20 sec. There there is a long low-level emission from T+50 to T+200 sec.
T90 (15-350 keV) is 10.0 +- 3.5 sec (estimated error including systematics).
The time-averaged spectrum from T-6.6 to T+16.3 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 0.88 +- 0.25,
and Epeak of 133 +- 54 keV (chi squared 84.4 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 1.00 +- 0.04 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T-0.12 sec in the 15-150 keV band is
29.7 +- 1.5 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.35 +- 0.06 (chi squared 95.5 for 57 d.o.f.). All the quoted errors
are at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/452685/BA/
GCN Circular 11996
Subject
GRB 110503A - TLS Afterglow Observations
Date
2011-05-03T23:19:12Z (14 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, S. Schmidl, C. Hoegner, B. Stecklum, S. Schumann and M.
Hartmann (TLS Tautenburg) report:
We observed the afterglow of GRB 110503A (M. Stamatikos et al., GCN 11991,
G. Leloudas et al., GCN 11994) at z=1.613 (A. de Ugarte Postigo et al.,
GCN 11993) with the 2m/1.34m Schmidt telescope of the Thueringer
Landessternwarte Tautenburg under excellent observing conditions (low
airmass, good transparency and seeing) starting during dawn at 0.098715
days after the GRB.
Observations consisted of 3 x 180 s each in Z, Ic, Rc, V, B, followed by 3
x 300 s each in Z, Ic, Rc, V, B. The afterglow is detected on the single
images.
Assuming the USNO-B1.0 1421-0227752 star at RA = 08:51:10.01 (132.791692)
Dec. = +52:11:04.75 (+52.184653) has R = 16.91 (mean of R1 and R2 mags,
0.06 mags difference), we find for two Rc band observations:
t (days after trigger) = 0.1187616, Rc = 19.07 +/- 0.03
t (days after trigger) = 0.1750347, Rc = 19.51 +/- 0.04
Errors are statistical only.
Observations are continuing as weather permits with 600 s exposures in all
five colors.
This message may be cited.
GCN Circular 11997
Subject
GRB 110503A: redshift confirmation from TNG
Date
2011-05-04T00:28:12Z (14 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
P. D'Avanzo (INAF/OAB), V. D'Elia (ASI/ASDC), L. Di Fabrizio, A. Gurtu
(INAF/TNG), report on behalf of a larger collaboration:
We observed the optical afterglow of GRB 110503A (Stamatikos et al. GCN
11991) with the Italian TNG located in La Palma, equipped with the DOLORES
camera in spectroscopic mode.
The optical afterglow (Leloudas et al. GCN 11994; Kann et al. GCN 11996)
is clearly detected in the unfiltered acquisition image, with a magnitude
R~19.5 at at t-t0=4.85 hours (using the calibration of Kann et al. GCN
11996).
A low-resolution spectrum was taken at a mean time t-t0=5.25 hours. The
adopted grism was LR-B, covering the wavelength range 3900-8200 AA with a
resolution of R~600.
Using a preliminary wavelength calibration we clearly detect several
absorption features, including CIV, SiII, AlIII, AlII, MgII and MgI, all
at a common redshift z=1.61, in agreement with the value reported by de
Ugarte Postigo et al. (GCN 11993).
At the same redshift we also detect the fine structure line SiII*1533.
This absorption feature is likely produced in the GRB host, further
supporting the statement that z=1.61 is the afterglow redshift.
GCN Circular 11998
Subject
GRB 110503A: PAIRITEL NIR Detection
Date
2011-05-04T06:36:46Z (14 years ago)
From
Adam Morgan at U.C. Berkeley <qmorgan@gmail.com>
A. N. Morgan, and J. S. Bloom (UC Berkeley) report:
We observed the field of GRB 110503A (Stamatikos et al., GCN 11991)
with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona under poor sky
conditions. Observations began at 2011-05-04 02:46:35 UT, ~9.2 hours
after the Swift Trigger. In mosaics (effective exposure time of 1.28
hours) taken simultaneously in the J and H filters, we marginally
detect a source at the optical afterglow location (Stamatikos et al.,
GCN 11991; Leloudas et al., GCN 11994; Kann et al., GCN 11996). Our
preliminary Ks band reduction is corrupted.
The preliminary photometry yields:
post burst
t_mid (hr) exp.(hr) filt mag m_err
10.2 1.28 J 18.19 0.26
10.2 1.28 H 17.86 0.36
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 11999
Subject
GRB 110503A: Swift-XRT refined Analysis
Date
2011-05-04T07:00:38Z (14 years ago)
From
Kim Page at U.of Leicester <kpa@star.le.ac.uk>
K.L. Page (U. Leicester) and M. Stamatikos (OSU/NASA/GSFC) report on
behalf of the Swift-XRT team:
We have analysed 8.2 ks of XRT data for GRB 110503A (Stamatikos et al.
GCN Circ. 11991), from 166 s to 28.4 ks after the BAT trigger. The
data comprise 1.1 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN. Circ 11992).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.059 (+/-0.013).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.86 (+/-0.04). The
best-fitting absorption column is 2.2 (+/-0.6) x 10^21 cm^-2, at a
redshift of 1.613, in addition to the Galactic value of 2.6 x 10^20
cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index
of 2.01 (+/-0.08) and a best-fitting absorption column of 2.4 (+/-1.0)
x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.3 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 2.6 x 10^20 cm^-2
Intrinsic column: 2.4 (+/-1.0) x 10^21 cm^-2 at z=1.613
Photon index: 2.01 (+/-0.08)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00452685.
This circular is an official product of the Swift-XRT team.
GCN Circular 12000
Subject
GRB 110503A: Swift/UVOT Observations
Date
2011-05-04T10:58:36Z (14 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (MSSL-UCL) & M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift-UVOT team
The Swift/UVOT began settled observations of the field of GRB 110503A 212s
after the trigger (Stamatikos et al., GCN Circ. 11991). We detect a fading
source in all filters at a refined position of RA(J2000), DEC(J2000)=
132.77588 deg,52.20767 deg. This is equivalent to:
RA (J2000) 8:51:06.21
Dec (J2000) 52:12:27.6
with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
This is consistent with the UVOT position reported in Stamatikos et al.
(GCN Circ. 11991) and with the enhanced position of the X-ray afterglow
(Goad et al., GCN Circ. 11992).
Preliminary magnitudes using the UVOT photometric system (Poole et al. 2008,
MNRAS, 383, 627) for the finding chart (FC) and summed exposures at the
location of the optical afterglow are:
Filter T_start(s) T_stop(s) Exp(s) Mag
#####################################################
wh (FC) 212 362 147 15.82 +/- 0.02
wh 864 1014 147 17.09 +/- 0.03
v 368 388 20 16.23 +/- 0.14
b 469 488 19 16.79 +/- 0.10
u 445 464 19 15.87 +/- 0.09
uvw1 419 438 19 16.15 +/- 0.15
uvm2 394 414 19 17.27 +/- 0.32
uvw2 519 539 19 17.72 +/- 0.31
#####################################################
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 12001
Subject
GRB 110503A: SARA-N Observations and Photometric Calibration
Date
2011-05-04T17:13:05Z (14 years ago)
From
Adria C. Updike at Clemson U <aupdike@clemson.edu>
Adria C. Updike (NASA/GSFC), D. A. Kann (TLS Tautenburg), Dieter H.
Hartmann (Clemson University), and Ken Rumstay (Valdosta State University)
report:
We observed the field of GRB 110503A (M. Stamatikos et al., GCN 11991)
with the SARA-North 0.9m telescope located at KPNO under good conditions
beginning about 13 hours after the trigger and continuing for half an
hour. We detect the afterglow in each 120 sec exposure. In a stacked 20
min image with mean time 0.5484375 days after the trigger, we detect the
afterglow at R = 20.20 +/- 0.07 using the SDSS-derived magnitude of the
comparison star given by Kann et al. (GCN 11996). Further observations
are planned.
The comparison star utilized by Kann et al. has the following SDSS
magnitudes (transformation from Lupton (2005) and Jordi et al. (2006):
u = 21.214
g = 18.546
r = 17.166
i = 16.485
z = 16.111
and Vega magnitudes:
U = 20.431
B = 19.193
V = 17.802
R = 16.819
I = 15.942
Z = 15.562
GCN Circular 12002
Subject
GRB 110503A: Millimeter observation from SMA
Date
2011-05-04T22:25:52Z (14 years ago)
From
Antonio Deugarte at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (DARK/NBI), G. Petitpas (SMA) and S. Martin (ESO)
report on behalf of a larger collaboration:
We have observed the afterglow of GRB 110503A (Stamatikos et al.
GCNC11991) with the Submillimeter Array (SMA, Hawaii, U.S.A.).
Observations were performed at 217GHz (1.4 mm) using 5 antennas under
unstable weather conditions (optical depth at 225 GHz ~0.25, humidity
~50%). The GRB field was observed for 268 minutes (on-source), starting at
1:15 UT, with mean epoch on 4 May at 5:36 UT, 12.0 hours after the burst.
We do not detect any significant flux at the position of the optical
afterglow, imposing a 3-sigma detection limit of 5.1 mJy.
[GCN OPS NOTE(05may11): Per author's request, the burst name
in the Subject-line was corrected.]
GCN Circular 12003
Subject
GRB 110503A: Centimeter observation from EVLA
Date
2011-05-04T23:24:57Z (14 years ago)
From
Dale A. Frail at NRAO <dfrail@nrao.edu>
Dale A. Frail (NRAO), Ashley Zauderer (Harvard), and Edo Berger
(Harvard) report on behalf of a larger collaboration:
We imaged a field toward the Swift burst GRB 110503A (GCN 11991,11995)
with the EVLA starting on 2011 May 4.04 (i.e. 7.4 hrs after the
burst). The EVLA observed at two frequencies (1 GHz bandwidth each)
centered at 19.2 GHz and 24.5 GHz. In a preliminary data analysis we
find a unresolved radio source within the UVOT error circle (GCN
12000) with a mean flux density of 160 +/- 15 uJy and a position
(J2000) of RA=08:51:06.21, Dec.=+52 12 27.43, with a conservative
error of +/-0.05 arcsec.
We caution that these results are only preliminary. Further
observations are planned.
GCN Circular 12004
Subject
GRB 110503A: R-band Detection
Date
2011-05-05T00:43:08Z (14 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
Myungshin Im (CEOU/Seoul National Univ), Hyun-Il Sung (KASI),
and Yuji Urata (NCU) on behalf of EAFON
We observed GRB 110503A (Stamatikos et al., GCN 11991) in R-band
with a 1.0-m telescope at Mt. Lemmon, Arizona. The observation
started at 05-04-03:24:30 UT. We detect the afterglow with a
magnitude at R ~ 20.28 +- 0.09 mag (mid-time of ~10.0 hrs after
BAT alert) based on the photometry calibration star reported by
Updike et al.(GCN 12001).
Further analysis of the data and the follow-up observations of
the object is ongoing. We thank the LOAO operator, I.-K. Baek
for her assistance with the observation.
GCN Circular 12005
Subject
GRB 110503A: optical observation in CrAO
Date
2011-05-05T01:01:22Z (14 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Pavlenko (CraO), A. Volnova (SAI MSU), A. Baklanov (CrAO), A. Pozanenko
(IKI) on behalf of larger GRB follow up collaboration report:
We observed the field of GRB 110503A (Stamatikos et al. GCN 11991) with
Shajn telescope of CrAO observatory on May. 3 starting (UT) 23:56. We took
several frames with exposure of 60s in R-band. The afterglow (Stamatikos et
al. GCN 11991) is well detected in each single frame. A preliminary
photometry is based on the USNO B1.0 star 1421-0227752 (08:51:10.01
+52:11:04.75) assuming R=16.819 (Updike et al. GCN 12001):
T0+ Filter, Exposure, mag.
(mid, d) (s)
0.26433 R 60 19.00 +/- 0.08
0.27991 R 60 19.24 +/- 0.18
0.29450 R 60 19.22 +/- 0.08
GCN Circular 12008
Subject
Konus-Wind observation of GRB 110503A
Date
2011-05-05T09:50:41Z (14 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 110503A, (Swift/BAT trigger=452685:
Stamatikos et al., GCN 11991; Sakamoto et.al, GCN 11995)
triggered Konus-Wind at T0=63341.862s UT (17:35:41.862)
The burst light curve consists of a single pulse
with a total duration of ~12 s.
The emission is seen up to ~4 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB110503_T63341/
As observed by Konus-Wind the burst
had a fluence of (2.6 � 0.2)x10-5 erg/cm2,
and a 64-ms peak flux, measured from T0+2.304 s,
of (1.0 � 1)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+10.752 s) is best fitted
in the 20 keV - 5 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.98 (-0.08, +0.09),
the high energy photon index beta = -2.7 (-0.5, +0.2),
the peak energy Ep = 219(-19, +20) keV,
chi2 = 69.5/76 dof.
The spectrum at the maximum count rate
(measured from T0+1.792 s to T0+2.560 s) can be fitted
in the 20 keV - 5 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -0.44 (-0.16, +0.19),
the high energy photon index beta = -2.75 (-0.4, +0.3),
the peak energy Ep = 211(-23, +25) keV,
chi2 = 55.4/48 dof.
Assuming the afterglow redshift z = 1.61 (de Ugarte Postigo et al.,
GCN 11993; D'Avanzo et al., GCN 11997) and a standard cosmology model
with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73,
the isotropic energy release E_iso is (1.77 � 0.15)x10^53 erg,
the peak luminosity L_iso_max is (1.83 � 0.18)x10^53 erg/s,
and Ep_rest is 570 � 50 keV.
All the quoted results are preliminary.
All the quoted errors are at the 90% confidence level.
GCN Circular 12009
Subject
GRB 110503A optical observations
Date
2011-05-05T10:50:09Z (14 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Eric Broens (Mol, Belgium) and David Boyd (West Challow, Oxfordshire, UK)
separately reported to the AAVSO International High Energy Network the
following optical observations of GRB 110503A (GCN Circ. #11991,
Stamatikos et al.):
E. Broens (VVS WVS, Belgium) reports a detection of GRB 110503A at CR =
19.6 +/- 0.2 on 2011 May 3.921 UT (JD 2455685.421; midpoint of exposures),
approximately 4.5 hours after the Swift trigger (GCN Circ. #11991,
Stamatikos et al.). Broens obtained 41 frames of 60 seconds exposure in a
clear filter using a 0.2-meter f7 SCT telescope with SBIG ST-7MXE CCD
camera. An ensemble of three nearby SDSS stars were used as comparisons,
with their R-band magnitudes calculated using the Jester et al. (2009, AJ
130, 873) relations. Comparison stars used were: SDSS J085110.53+521301.8
(R = 17.98) and SDSS J085110.02+521104.6 (R=17.20). The measured position
of the GRB was:
RA: 08 51 06.3 , Dec: +52 12 26.9
Prior to acquisition of the unfiltered frames, a total of thirty 60-second
frames (1800s total) were taken with a Cousins R filter centered at 2011
May 3.895 approximately four hours after the burst. The filtered
observations yielded an upper limit of Rc < 18.7.
D. Boyd (West Challow, Oxfordshire, UK) reports V-band optical time series
of GRB 110503A obtained using a 0.35-m SCT with a Starlight Express
SXVR-H9 CCD camera. A total of 150 60-second frames were obtained, and
these were stacked in groups of 30 to obtain five 1800-second
integrations. The burst was detected in all frames. The resulting
time-series are as follows:
2011 May 3.89920 UT V=19.40 +/- 0.04
2011 May 3.92022 UT V=19.57 +/- 0.04
2011 May 3.94123 UT V=19.71 +/- 0.04
2011 May 3.96225 UT V=19.74 +/- 0.05
2011 May 3.98326 UT V=19.96 +/- 0.05
Magnitudes were obtained using Astrometrica software using UCAC3 for
positions and photometry; Boyd reports that magnitudes were obtained using
varying ensembles of between 14 and 19 stars per stacked image. Boyd also
notes that the coorindates of the GRB on all frames was
RA: 08 51 06.19 , Dec: +52 12 27.3 (J2000)
The AAVSO International High Energy Network was made possible through
grants from the Charles Curry Foundation and NASA.
GCN Circular 12010
Subject
GRB 110503A: Jet Break seen from TLS
Date
2011-05-06T00:36:27Z (14 years ago)
From
Alexander Kann at TLS Tautenburg <kann@tls-tautenburg.de>
D. A. Kann, S. Schmidl, B. Stecklum and C. Hoegner (TLS Tautenburg) report:
Observations of GRB 110503A (M. Stamatikos et al., GCN 11991) and its
afterglow are continuing at TLS Tautenburg (D. A. Kann et al., GCN 11996).
In the first night, we observed for a total of 6 hours, with conditions
becoming worse (increasing airmass and passing clouds). 43 detections in
BVRIZ were secured.
In the second night, observational conditions were challenging, with
passing clouds and high airmass at the time observations could begin. We
obtained 3 x 300 s in Rc, 3 x 450 s in V and only a single 450 s B
observation. The afterglow is faintly detected in the Rc and V stacks as
well as the B image. Using the comparison star of GCN 11996, as calibrated
by A. Updike et al. (GCN 12001), we find:
t (days after trigger) = 1.24878, Rc = 21.39 +/- 0.12
We re-observed the afterglow position in the third night under moderate
conditions (low airmass, good seeing, but low transparency). We obtained 6
x 600 s in the Rc band. Even in the stack, the afterglow is only faintly
detected. We find:
t (days after trigger) = 2.14026, Rc = 22.63 +/- 0.28
Fitting our Rc band data shows a clear break, with alpha_1 = 0.83 +/-
0.03, alpha_2 = 2.3 +/- 0.6 (due to sparse data with large errors), t_b =
1.06 +/- 0.14 days. While both the post-break decay slope as well as the
break time are insecure due to sparsity of the data, the data point at
2.14 days lies a complete magnitude under the extrapolation of the early
decay, making the existence of a break itself secure.
We propose this is the jet break of the afterglow.
Deeper follow-up with telescopes of larger aperature is highly encouraged.
This message may be cited.
GCN Circular 12011
Subject
GRB 110503A: TAROT Calern observatory optical observations
Date
2011-05-06T16:56:18Z (14 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz A. (CESR-OMP), Gendre B. (ASDC),
Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report:
We imaged the field of GRB 110503A detected by SWIFT
(trigger 451901) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
The observations started 1.9h after the GRB trigger
(trigger occured during daytime). The elevation of
the field decreased from 69 degrees above horizon
and weather conditions were good.
We detect the candidate couterpart mentioned by
Stamatikos et al. 2011 (GCNC 11991) on co-added
series of exposures. We used the reference star
USNO B1.0 1421-0227752 (08:51:10.01 +52:11:04.75
J2000) described by Kann et al. 2011 (GCNC 11996)
assuming R=16.819 (Updike et al. GCN 12001).
start stop R
1.96h - 2.65h 18.42 +/- 0.15
2.71h - 3.99h 19.11 +/- 0.10
4.04h - 5.33h 19.51 +/- 0.12
5.38h - 7.43h 19.93 +/- 0.15
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
From 1.96h to 7.43h, the decay slope is alpha = 1.1.
GCN Circular 12014
Subject
GRB 110503A optical observation
Date
2011-05-16T15:06:57Z (14 years ago)
From
AAVSO GRB Network at AAVSO <matthewt@aavso.org>
Andrea Tasselli (Lincoln, Lincolnshire, UK) reports to the AAVSO
International High Energy Network the following optical observation of GRB
110503A (GCN Circ. #11991, Stamatikos et al.):
A. Tasselli (Lincoln, Lincolnshire, UK) reports a detection of GRB 110503A
at an unfiltered, Sloan r-derived magnitude of cr = 19.1 +/- 0.1 on 2011
May 05.9167 (JD 2455685.4167; midpoint of exposures), approximately 4
hours after the Swift trigger (GCN Circ. #11991, Stamatikos et al.).
Tasselli obtained 30 unfiltered images of 120 seconds exposure for a total
of 3600 seconds. Tasselli used a 0.2-meter Maksutov-Cassegrain (f/6.8)
with a Starlight SXV-H9 CCD camera. Photometry of the OT was done using
the Iris photometry package with an ensemble of six SDSS stars:
SDSS J085118.11+521119.2, r=14.756;
SDSS J085118.96+521055.4, r=15.565;
SDSS J085110.02+521104.6, r=17.177;
SDSS J085119.59+521406.2, r=13.871;
SDSS J085131.83+521343.8, r=13.893; and
SDSS J085110.53+521301.8, r=17.749.
The position of the OT was measured using the Astrometrica package with 55
UCAC3 reference stars, and was found to be
RA(J2000) = 08 51 06.2
Dec(J2000) = +52 12 30
in good agreement with other measurements.
The AAVSO International High Energy Network was made possible through
grants from the Charles Curry Foundation and NASA.