GRB 120327A
GCN Circular 13188
Subject
GRB 120327A: SMARTS optical/IR afterglow observations
Date
2012-04-02T04:00:35Z (14 years ago)
From
Bethany Cobb at GWU <bcobb@gwu.edu>
B. E. Cobb (GWU), reports:
Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained
optical/IR imaging of the error region of GRB 120327A (GCN 13123,
Sbarufatti et al.) over several epochs, starting ~1.8 hours post-burst.
For each epoch, several dithered images were obtained
with
total summed exposure times of 15 min in V and I and 12 min in J and K.
The fading afterglow of GRB 120327A (e.g. GCN 13123, Sbarufatti et al.; GCN
13124,
Klotz et al.; GCN 13125, Smith et al.) was detected with the following
magnitudes (or
3-sigma limits):
mid-exposure
time V mag I mag J
mag K mag
1.8 hrs 18.92+/-0.03 17.73+/-0.04 16.46+/-0.07
14.83+/-0.09
4.1 hrs 19.97+/-0.03 18.57+/-0.04 17.42+/-0.08
15.73+/-0.09
25.8 hrs >21.9 >20.9 >19.0
>17.4
(Optical photometry is calibrated against Landolt standard stars
and IR photometry is calibrated against 2MASS stars in the field.)
Between about 1.8 hrs and 4.1 hrs post-burst, the GRB afterglow fades with
a decay rate of approximately alpha = 1 (where afterglow flux is
proportional to t^-alpha).
GCN Circular 13180
Subject
GRB120327A - ATCA radio afterglow detection at 34GHz
Date
2012-03-31T21:01:15Z (14 years ago)
From
Paul Hancock at U of Sydney <hancock@physics.usyd.edu.au>
P. Hancock, T. Murphy, B. Gaensler, M. Bell, D. Burlon (University of
Sydney/CAASTRO), A. de Ugarte Postigo (Dark Cosmology / IAA)
We observed GRB120327A (GCN13123) with the Australia Telescope Compact
Array for 40 mins centered on 17:55UT on March 31 2012 (T0+4.625days).
We find an unresolved radio source at ra=16:27:27.4, dec=-29:24:54.0
with a flux of 0.72+/-0.03 mJy. This position is consistent with the
optical position of GCN13138.
Further observations are planned.
These observations were obtained as part of ATCA project C2689. We thank
the observatory staff for their support and scheduling the observations.
The Australia Telescope is funded by the Commonwealth of Australia for
operation as a National Facility managed by CSIRO.
GCN Circular 13169
Subject
GRB 120327A: MITSuME Ishigakijima Optical Upper Limits at 1 day afterthe burst
Date
2012-03-29T14:06:52Z (14 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 collaboration:
We observed the field of GRB 120327A (Sbarufatti et al., GCNC 13123)
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 2012-03-28 17:27:54 UT (~1.61 days after the
burst). We could not detect the previously reported afterglow
(Klotz et al., GCNC 13124; Smith et al., GCNC 13125; Kuroda et al.,
GCNC 13156) in all the three bands.
Three sigma upper limits of the OT are listed below. We used GSC2.3
catalog for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' Rc Ic
----------------------------------------------------------------------
1.62756 17:58:57 1500.0 >20.5 >20.2 >19.0
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 13164
Subject
GRB 120327A: Zadko optical observations
Date
2012-03-28T21:29:19Z (14 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
A. Klotz (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA),
B. Gendre (ASDC/INAF-OAR), M. Boer (UNS-CNRS-OCA),
A. Williams (PO-UWA), R. Martin (PO-UWA) report:
We imaged the field of GRB 120327A detected by SWIFT
(trigger 518731) with the Zadko robotic telescope (D=100cm)
located at Gingin observatory, Australia.
The observations started 41 hours after the GRB trigger.
Weather conditions were excellent.
The optical transcient (Sbarufatti et al. GCNC 13123)
is detected very close to the limiting magnitude
of a co addition of images obtained with no filter.
start end Rmag dmag filter
(day) (day)
1.73 1.75 22.0 0.3 CR
Magnitude was estimated with the nearby star
NOMAD1 0605-0398765 (246.8438328 -29.4187269)
using R=14.930.
GCN Circular 13156
Subject
GRB 120327A: MITSuME Ishigakijima Optical Observation
Date
2012-03-28T14:21:01Z (14 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 collaboration:
We observed the field of GRB 120327A (Sbarufatti et al., GCNC 13123)
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 2012-03-27 19:19:59 UT (~16.4 h after the
burst). We detected the previously reported afterglow (Klotz et al.,
GCNC 13124; Smith et al., GCNC 13125) in Rc and Ic bands.
Photometric results of the OT are listed below. We used GSC2.3 catalog
for flux calibration.
#T0+[day] MID-UT T-EXP[sec] g' Rc Rc_err Ic Ic_err
----------------------------------------------------------------------
0.70335 19:48:05 2640.0 >21.3 20.3 0.1 19.7 0.3
----------------------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 13152
Subject
GRB 120327A: NOT optical observations
Date
2012-03-28T05:38:24Z (14 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
Daniele Malesani (DARK/NBI), Johan P. U. Fynbo (DARK/NBI), Pall
Jakobsson (Univ. Iceland), Jens Jessen-Hansen (NOT and Univ. Aarhus),
Jyri Lehtinen (NOT and Univ. Helsinki), report:
We observed the optical afterglow of GRB 120327A (Sbarufatti et al., GCN
13123) with the NOT equipped with ALFOSC in imaging mode. Observations
were carried out in the R band, for a total exposure time of 30 min,
with a seeing of 1.2".
The optical afterglow is well detected in our images taken at a mean
epoch of March 28.164 UT (1.05 days after the GRB), with a magnitude R =
21.8+-0.16 calibrated against nearby USNO-B1 stars (R1 magnitudes).
This value is in fair agreement with the extrapolation of the R-band
data reported in the literature (LaCluyze et al., GCN 13127; Klotz et
al., GCNs 13124, 13132; Sudilovsky et al., GCN 13129; Gorosabel et al.,
GCN 13130; Im et al., GCN 13140; Meehan et al., GCN 13144). The
afterglow has faded following a single power-law decay with slope alpha
= 1.3 between 12 min and 1 day after the GRB, though small-scale
variability may be present (see also LaCluyze et al., GCN 13127).
GCN Circular 13146
Subject
GRB 120327A: GTC redshift confirmation
Date
2012-03-27T21:59:50Z (14 years ago)
From
Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>
R. S�nchez-Ram�rez, J. Gorosabel, A. J. Castro-Tirado (IAA-CSIC Granada),
M. A. Rivero and G. G�mez-Velarde (GTC La Palma), on behalf of a larger
collaboration, report:
"Following the detection of the optical afterglow to GRB 120327A
(Sbarufatti et al. GCNC 13123), we have taken three spectra (400s each)
with the 10.4m GTC (+ OSIRIS) at the Spanish Observatorio del Roque de los
Muchachos (La Palma). The spectra, covering the range 3800-7800 A were
taken starting 2.33 hr post burst, and reveal a strong damped Ly-alpha
system besides several absorption features, including SiIV, SiII, CIV,
FeII, AlII (and others) at a common redshift of 2.813, consistent with the
value reported by Perley and Tanvir (GCNC 13133) and Kruehler et al.
(GCNC 13134)."
This message can be quoted.
GCN Circular 13144
Subject
GRB 120327A afterglow detection
Date
2012-03-27T20:48:42Z (14 years ago)
From
Petr Kubanek at AIO <pkubanek@gmail.com>
S. Meehan, L. Hanlon, M. Topinka (UCD Dublin), P. Kubanek (FZU AV CR
Prague), report on behalf of a large collaboration:
We imaged the field of GRB 120327A detected by SWIFT (trigger 518731)
with the Watcher robotic telescope (D=40cm) located at Boyden
Observatory, Bloemfontein, South Africa.
Our first good observation was 14.4 min after the GRB trigger, 3 min
after receipt of the GCN notice. The source was close to the zenith
with an airmass of 1.01.
We detect a fading source in the error box given by SWIFT, which
coincides with candidate counterpart mentioned by Sbarufatti et al.
(GCN 13123).
The optical transient was measured at 15.5 +/- 0.1 mag @ 14.4 minutes
after the trigger in the clear filter.
Magnitudes were estimated using the nearby USNO-B1 stars as references
and are not corrected for galactic dust extinction.
Analysis of the remaining images is on-going.
GCN Circular 13141
Subject
GRB 120327A: Swift-XRT refined Analysis
Date
2012-03-27T16:17:03Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
M.C. Stroh (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), C.
Pagani (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), J.A. Kennea
(PSU) and B. Sbarufatti report on behalf of the Swift-XRT team:
We have analysed 7.3 ks of XRT data for GRB 120327A (Sbarufatti et al.
GCN Circ. 13123), from 66 s to 0 s after the BAT trigger. The data
comprise 267 s in Windowed Timing (WT) mode (the first 7 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 Osborne et
al. (GCN. Circ 13135).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.95 (+0.10, -0.11). At T+217 s the decay
flattens to an alpha of 0.62 (+0.09, -0.13) before breaking again at
T+2540 s to a final decay with index alpha=1.42 (+0.13, -0.12).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.98 (+/-0.08). The
best-fitting absorption column is 1.5 (+0.5, -0.4) x 10^22 cm^-2, at a
redshift of 2.81, in addition to the Galactic value of 1.4 x 10^21
cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index
of 1.79 (+0.11, -0.10) and a best-fitting absorption column of 1.5
(+0.8, -0.7) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10
keV flux conversion factor deduced from this spectrum is 4.4 x 10^-11
(5.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 1.4 x 10^21 cm^-2
Intrinsic column: 1.5 (+0.8, -0.7) x 10^22 cm^-2 at z=2.81
Photon index: 1.79 (+0.11, -0.10)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00518731.
This circular is an official product of the Swift-XRT team.
GCN Circular 13140
Subject
GRB 120327A: CQUEAN grizY Observation
Date
2012-03-27T14:11:30Z (14 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
Myungshin Im, Jae-Woo Kim, and Duho Kim (CEOU/Seoul National Univ.)
We observed GRB 120327A (Sbarufatti et al., GCN 13123) in
g,r,i,z,Y filters using CQUEAN camera on the 2.1m Otto-Struve
telescope at McDonald Observatory, Texas, US.
The observation started at 2012-03-27 11:00:08 UT,
or about 8 hours after the BAT alert.
In all of the g,r,i,z,Y-band images taken with 300 sec
exposure each, we identify the afterglow (r ~ 20 AB mag)
which was reported earlier by several groups
(Klotz et al. GCN 13124, Smith et al. GCN 13125,
Soulier et al. GCN 13126, LaCluyze et al. GCN 13127,
Covino et al. GCN 13128,Sudilovsky et al. GCN 13129,
Grosabel et al. GCN 13130).
Further observations are planned.
GCN Circular 13138
Subject
GRB 120327A: Swift/UVOT further analysis
Date
2012-03-27T12:50:38Z (14 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (MSSL-UCL) and B. Sbarufatti (INAF-OAB/PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120327A
141 s after the BAT trigger (Sbarufatti et al., GCN Circ. 13123).
A source consistent with the enhanced XRT position (Osborne et al.
GCN Circ. 13135) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 16:27:27.48 = 246.864500 (deg.)
Dec (J2000) = -29:24:53.74 = -29.414928 (deg.)
with an estimated uncertainty of 0.48 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
v 448 468 20 15.68 +/- 0.10
b 396 416 20 16.97 +/- 0.11
u 141 391 246 18.02 +/- 0.08
w1 497 1295 97 >19.0
m2 622 1271 78 >19.2
w2 424 1222 97 >19.6
The absence of detection in uvw1, uvm2, and uvw2 is consistent with the
reported redshift of 2.81 (Perley & Tanvir, GCN Circ 13133, and
Krueler et al, GCN Circ. 13134).
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.34 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 13137
Subject
GRB 120327A: Swift-BAT refined analysis
Date
2012-03-27T12:22:18Z (14 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (OSU), B. Sbarufatti (INAF-OAB/PSU),
J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120327A (trigger #518731)
(Sbarufatti, et al., GCN Circ. 12123). The BAT ground-calculated position is
RA, Dec = 246.854, -29.415 deg, which is
RA(J2000) = 16h 27m 25.0s
Dec(J2000) = -29d 24' 55.5"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 76%.
The mask-weighted light curve shows 3 main peaks (two weak peaks, then the
main peak). The first starts at ~T-25 sec, peaks at ~T+2 sec; and the second
peaks at ~T+18 sec. The main peak starts at ~T+30 sec, peaks at ~T+37 sec,
and returns to baseline at ~T+180 sec. T90 (15-350 keV) is 62.9 +- 7.5 sec
(estimated error including systematics).
The time-averaged spectrum from T-15.79 to T+74.58 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.52 +- 0.06. The fluence in the 15-150 keV band is 3.6 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+37.09 sec in the 15-150 keV band
is 3.9 +- 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/518731/BA/
GCN Circular 13135
Subject
GRB 120327A: Enhanced Swift-XRT position
Date
2012-03-27T08:14:58Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1105 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 120327A, 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 = 246.86448, -29.41491 which is equivalent
to:
RA (J2000): 16h 27m 27.47s
Dec (J2000): -29d 24' 53.7"
with an uncertainty of 1.6 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 13134
Subject
GRB 120327A: X-shooter redshift
Date
2012-03-27T07:38:40Z (14 years ago)
From
Thomas Kruehler at Dark Cosmology Center <tom@dark-cosmology.dk>
T. Kruehler, J. P. U Fynbo, B. Milvang-Jensen (all DARK), N. Tanvir (U. Leicester) and P. Jakobsson (U. Iceland) report on behalf of a larger collaboration.
We observed the optical/NIR afterglow (e.g., Sbarufatti et al., GCN# 13123, Klotz et al., GCN#13124, Smith et al., GCN#13125) of the Swift GRB 120327A (Sbarufatti et al., GCN# 13123) with the VLT/UT2 equipped with the X-shooter spectrograph. Observations started around 05:03 UT on 2012-03-27, which is roughly 2.13 hrs after the trigger. Four exposures in a nodding pattern with an integration time of 600 s each were obtained. The spectrum covers an approximate wavelength range between 3100 and 23000 AA. The slit width was set to 1" in the ultra-violet/blue arm, and 0.9" in the visual and near-infrared arm, resulting in a resolving power range of approximately 4500-7500.
Preliminary reduction of the spectrum shows a well detected continuum with several absorption features, that we identify with Ly-limit and Ly-alpha as well as absorption lines of CII/CII*, SiII/SiII*, AlI, FeII and MgII at a redshift of 2.813. This is confirms previous reports based on spectroscopy (Perley & Tanvir, GCN #13133) and photometry (Sudilovsky et al. GCN #13129).
We are grateful for the excellent support from the Paranal Observatory staff, in particular Dimitri Gadotti. We acknowledge private communication with the GROND team, in particular Vlad Sudilovsky.
GCN Circular 13133
Subject
GRB 120327A: Gemini-South redshift
Date
2012-03-27T07:35:33Z (14 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) and N. R. Tanvir (U. Leicester) report on behalf
of a larger collaboration:
On March 27 starting at 06:01 UT (186 minutes after the BAT trigger) we
began spectroscopic observations of the optical afterglow of GRB 120327A
(Sbarufatti et al., GCN 13123) using GMOS-South on the Gemini-South 8-m
telescope. We acquired four exposures of 800s each using the B600
grating, with wavelength coverage between 3865-6680 Angstroms.
In the reduced spectrum we identify a strong damped Lyman-alpha system
at z=2.81 as well as numerous narrow absorption lines corresponding to
(among others) CIV, CII, OI, SiII at the same redshift, as well as
possible Lyman-beta. We therefore identify this as the redshift of the
GRB.
We thank German Gimeno and the Gemini staff for prompt execution of the
observations.
GCN Circular 13132
Subject
GRB 120327A: TAROT La Silla observatory optical decay
Date
2012-03-27T07:04:56Z (14 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
We continue observations of GRB 120327A (trigger 518731)
with the TAROT robotic telescope (D=25cm) located at the
European Southern Observatory, La Silla observatory, Chile.
An optical decay alpha=1.3 (+/- 0.3) is deduced from the
following observations:
No filter:
start end Rmag dmag filter
(sec) (sec)
1944.2 2234.6 16.96 0.17 CR
2387.2 3159.2 17.31 0.19 CR
3169.5 3938.0 17.81 0.09 CR
4156.0 4916.2 18.03 0.17 CR
4926.5 6102.7 18.84 0.13 CR
R filter:
start end Rmag dmag filter
(sec) (sec)
2767.6 3539.5 17.65 0.09 R
3948.0 4716.3 18.34 0.32 R
5116.5 7072.8 18.56 0.17 R
7472.9 10018.6 18.84 0.09 R
Photometry is relative to the star NOMAD1 0605-0398765:
(ra,dec) J2000 = (246.8438328,-29.4187269) R=14.930.
Magnitudes are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular 13130
Subject
GRB 120327A: IAC80 I-band observations
Date
2012-03-27T06:09:30Z (14 years ago)
From
Javier Gorosabel at IAA-CSIC <jgu@iaa.es>
J. Gorosabel, A. J. Castro-Tirado (IAA-CSIC, Granada), C. Walker, J. Court, R. Duffy, T. Edwards, M. Herath, J. Kirk, S. Patel, S. Prajs, B. Tunbridge, D. Williams, R. Wood, P. Wright, T. Munoz-Darias, C. Knigge, M. Coriat (University of Southampton) and R. Gimeno (IAC, Tenerife), report:
"We observed the optical counterpart of GRB 120327A (Sbarufatti et al., GCNC 13123) with the 82cm IAC80 telescope at the Observatorio del Teide, Tenerife, Spain. The observations were carried out in the I-band on 04:06 - 05:33 UT (starting 1.12 hours post burst) with a total exposure time of 14x300s. A preliminary photometry, against the USNO B1.0 catalogue, shows a clear decay from R~18 to R~19.2".
GCN Circular 13129
Subject
GROND observations of GRB 120327A
Date
2012-03-27T05:31:26Z (14 years ago)
From
Vladimir Sudilovsky at MPE <vsudilov@mpe.mpg.de>
V. Sudilovsky (MPE Garching), A. Nicuesa Guelbenzu (Tautenburg Observatory) and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 120327A (Swift trigger 518731; Sbarufatti et al., GCN #13123) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile).
Observations started at 03:34 UT, 39 minutes min after the GRB trigger, and are continuing. They were performed at an average seeing of 1.6" and at an average airmass of 2.3.
We found a single point source consistent with both the UVOT (Sbarufatti et al, GCN #13123) and Liverpool telescope (Smith et al., GCN #13125) afterglow position.
Based on the second of two 2.4 min of exposures in g'r'i'z' and 4 min in JHK, we estimate preliminary magnitudes (all in AB) at an observations midpoint 03:44 UT of
g' = 18.6 +- 0.1 mag,
r' = 17.5 +- 0.1 mag,
i' = 17.2 +- 0.1 mag,
z' = 17.0 +- 0.1 mag,
J = 16.3 +- 0.1 mag, and
H = 15.9 +- 0.1 mag
Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.34 mag in the direction of the burst (Schlegel et al. 1998). If this value is correct for the line-of-sight to this GRB, then the substantially reduced g-band flux suggests a redshift around 3.
GCN Circular 13128
Subject
GRB 120327A: REM NIR and optical observations
Date
2012-03-27T05:28:57Z (14 years ago)
From
Stefano Covino at Brera Astronomical Observatory <stefano.covino@gmail.com>
S. Covino, D. Fugazza, A. Rossi on behalf of the REM team report:
We imaged the field of GRB120327A (Sbarufatti et al., GCN 13123) with
the recently
re-aluminized REM telescope located at La Silla.
The optical counterpart also reported in GCN 13124 (Klotz et al.), GCN
13125 (Smith et al.)
and GCN 13126 (LaCluyze et al.) is well detected both in the optical
and in the NIR.
The source is detected from about 10 min from the GRB time and
observations are still in progress.
At 10min after the burst the source was approximately at H=12.69 +-
0.03, calibrated to 2MASS field stars.
GCN Circular 13127
Subject
Skynet/PROMPT observations of GRB120327A
Date
2012-03-27T05:17:36Z (14 years ago)
From
Aaron LaCluyze at U.North Carolina <lacluyze@email.unc.edu>
A. LaCluyze, J. Haislip, K. Ivarsen, D. Reichart, J. Moore, H. T.
Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E.
Speckhard, A.Trotter, and J. A. Crain report:
Skynet observed the field of GRB120327A (Sbarufatti et al., GCN 13123) with
the PROMPT telescopes located at CTIO in Chile beginning ~11 minutes after
the burst in BVRI. �Observations were delayed due to horizon limits. �We
detect a bright, fading afterglow at the location reported by Klotz et al.
(GCN 13124) in all filters. �A preliminary light curve, calibrated to
nearby USNO B1.0 stars, �can be found at:
http://skynet.unc.edu/grb/grb120327a.png
Further observations are ongoing.
GCN Circular 13125
Subject
GRB 120327A: Liverpool Telescope Observations
Date
2012-03-27T04:16:30Z (14 years ago)
From
James Smith at ARI,Liverpool John Moors U <rjs@astro.livjm.ac.uk>
R.J. Smith, Francisco Virgili (Liverpool JMU) report on behalf of the LJMU GRB group:
The 2-m Liverpool Telescope automatically observed Swift GRB 120327A (Sbarufatti et al., GCN Circ. 13123) on March 27, from 03:22:59.1 UT, corresponding to 27.7 minutes after the BAT trigger time. Within the XRT error circle we clearly detect an fading optical source at
16:27:27.46 , -29:24:54.00 J2000
with an uncertainty of 0.6 arcsec, confirming the observations of Klotz et al (GCN 13124). We estimate the magnitude of the afterglow as follows:
Mid time from Exp Filter Magnitude
GRB (min) (s)
---------------------------------------------
34.9 10 R 16.1 +/- 0.3
64.5 60 R 17.0 +/- 0.3
---------------------------------------------
Magnitudes are calibrated against nearby USNOB-1 stars.
Observations are continuing.
GCN Circular 13124
Subject
GRB 120327A: TAROT La Silla observatory optical detection
Date
2012-03-27T04:03:13Z (14 years ago)
From
Alain Klotz at CESR-CNRS <Alain.Klotz@free.fr>
Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR),
Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report:
We imaged the field of GRB 120327A detected by SWIFT
(trigger 518731) with the TAROT robotic telescope (D=25cm)
located at the European Southern Observatory,
La Silla observatory, Chile.
The observations started 32.40min after the GRB trigger.
The elevation of the field increased from
21 degrees above horizon and weather conditions
were good. Observations cannot begin earlier because
of the presence of the ESO 3.6 meter telescope that
hid the field of view!
We detect a new fading source in the error box given by SWIFT
We detected the candidate couterpart mentioned by Sbarufatti
et al. (GCNC 13123).
OT is still at R=17.5 at 45 min after GRB.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
This message may be cited.
GCN Circular 13123
Subject
GRB 120327A: Swift detection of a burst with an optical counterpart
Date
2012-03-27T03:17:21Z (14 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
B. Sbarufatti (INAF-OAB/PSU), S. D. Barthelmy (GSFC),
N. Gehrels (NASA/GSFC), E. A. Hoversten (PSU),
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), M. H. Siegel (PSU), M. Stamatikos (OSU/NASA/GSFC)
and T. N. Ukwatta (MSU) report on behalf of the Swift Team:
At 02:55:16 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120327A (trigger=518731). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 246.828, -29.415, which is
RA(J2000) = 16h 27m 19s
Dec(J2000) = -29d 24' 54"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows 3 main peaks
with a total duration of about 60 sec. The peak count rate
was ~6500 counts/sec (15-350 keV), at ~38 sec after the trigger.
The XRT began observing the field at 02:56:32.2 UT, 75.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 246.86308, -29.41514 which
is equivalent to:
RA(J2000) = 16h 27m 27.14s
Dec(J2000) = -29d 24' 54.5"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 110 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 (1.40 x
10^21 cm^-2, Kalberla et al. 2005), with an excess column of 1.9
(+1.51/-1.37) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 5.41e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 250 seconds with the U filter starting
140 seconds after the BAT trigger. There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 16:27:27.47 = 246.86445
DEC(J2000) = -29:24:53.8 = -29.41494
with a 90%-confidence error radius of about 0.64 arc sec. This position is 3.6
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.92 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.34.
Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti AT brera.inaf.it).
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.)