GRB 120311B
GCN Circular 13059
Subject
GRB 120311B: Optical follow-up
Date
2012-03-13T13:54:28Z (14 years ago)
From
Shashi Bhushan Pandey at ROTSE <shaship@umich.edu>
Brajesh Kumar, Vijay Kumar Bhatt, S.B. Pandey (ARIES, Nainital, India,
on behalf of larger Indian GRB collaboration).
GRB 120311B field (Marshall et al., GCN Circ 13038) was observed
with the newly installed 1.3m Devasthal Fast Optical Telescope at
Nainital. Several images in R_c pass-band (300 sec each) were taken
in two sessions starting at UT 21:11:10, 11-03-2012.
In the initial co-added R_c frame (3x300sec), we did not detect any
new optical source within the XRT error-box (Osborne et al.,
GCN Circ. 13042) down to a limiting magnitude of ~ 20.5 mag.
The photometry was done in comparison to nearby USNO- B1 stars.
This massage may be cited.
GCN Circular 13050
Subject
GRB 120311B: C88 optical limits
Date
2012-03-12T18:32:49Z (14 years ago)
From
Simone Leonini at Monarrenti Obs <s.leonini@iol.it>
Simone Leonini and Paolo Rosi (Montarrenti Observatory, Siena, Italy) report:
We observed the field of GRB 120311B (Swift trigger 517489, Marshall et al.,
GCN Circ 13038) with 0.53m RC telescope + U47 detector at Montarrenti Observatory
(Siena, Italy, IAU code C88).
The first session of observations was started at 2012-03-12 03:59:24 UT
and stopped at 2012-03-12 04:00:07 UT. The second session started at 04:11:47 UT
and stopped at 04.12.26 UT (~13 hours after the trigger).
Four unfiltered images of 40s exposure was obtained. We do not detect
any new point source in the coadded images (limit R~18.9, USNO-B1 catalogue)
within the enhanced XRT error circle (Osborne et al., GCN Circ. 13042).
Target was very low on the horizon.
[GCN OPS NOTE(12mar12): Distribution was delayed by ~3 hrs until an account
could be created.]
GCN Circular 13047
Subject
GRB 120311B: Swift/UVOT Upper Limits
Date
2012-03-12T12:15:09Z (14 years ago)
From
Alice Breeveld at MSSL-UCL <aab@mssl.ucl.ac.uk>
A. A. Breeveld (MSSL-UCL) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120311B
3072 s after the BAT trigger (Marshall et al., GCN Circ. 13038).
No optical afterglow consistent with the XRT position (Osborne et al.,
GCN Circ. 13042) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 3072 3222 147 >21.4
white 3072 16503 2114 >22.8
v 3228 21300 2013 >20.3
b 4048 15591 1233 >20.7
u 3843 5479 393 >19.7
w1 3638 22969 1136 >20.9
m2 3433 22206 1082 >20.8
w2 4460 17192 1754 >21.9
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.52 in the direction of the
burst (Schlegel et al. 1998).
GCN Circular 13046
Subject
GRB 120311B: MITSuME Okayama Optical upper limits
Date
2012-03-12T09:14:49Z (14 years ago)
From
Daisuke Kuroda at OAO/NAOJ <dikuroda@oao.nao.ac.jp>
D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (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 120311B (Marshall et al., GCNC 13038)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.
The observation started on 2012-03-11 16:48:04 UT (~1.7 h after the burst)
We did not find any new point source within the enhanced XRT circle
(Osborne et al., GCNC 13042) in all the three bands.
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
------------------------------------------------------
0.09146 17:19:52 4380.0 >18.7 >18.8 >18.3
0.15451 18:50:40 4740.0 >19.6 >19.6 >18.9
------------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 13045
Subject
GRB 120311B: Faulkes Telescope North observations
Date
2012-03-12T08:58:55Z (14 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB), F. Virgili (LJMU),
J. Japeli (U. Ljubljana) on behalf of a larger collaboration report:
"The 2-m Faulkes Telescope North robotically followed up GRB 120311B
(Swift trigger 517489, Marshall et al., GCN Circ 13038) 200 sec after
the GRB trigger time. Within the enhanced XRT error circle (Osborne et
al., GCN Circ. 13042) we do not detect any object in R and i' filters
down to the following limits:
Mid time from Exposure Filter Magnitude
GRB (hr) (s)
----------------------------------------------------------
0.29 240 R > 20.5
0.39 220 i' > 20.3
----------------------------------------------------------
Values are calibrated against nearby USNOB-1 field stars.
GCN Circular 13044
Subject
GRB 120311B: Swift-XRT refined Analysis
Date
2012-03-12T08:11:59Z (14 years ago)
From
Paolo D'Avanzo at INAF-OAB <paolo.davanzo@brera.inaf.it>
P. D'Avanzo (INAF-OAB) and F. E. Marshall (NASA/GSFC) report on behalf
of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 120311B (Marshall et al.
GCN Circ. 13038), from 3.1 ks to 22.9 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. The enhanced XRT
position for this burst was given by Osborne et al. (GCN. Circ 13042).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.69 (+/-0.11).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.01 (+0.22, -0.21). The
best-fitting absorption column is 3.6 (+0.9, -0.8) x 10^21 cm^-2, in
excess of the Galactic value of 1.6 x 10^21 cm^-2 (Kalberla et al.
2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum is 4.2 x 10^-11 (7.0 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 3.6 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^21 cm^-2
Excess significance: 3.9 sigma
Photon index: 2.01 (+0.22, -0.21)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00517489.
This circular is an official product of the Swift-XRT team.
GCN Circular 13042
Subject
GRB 120311B: Enhanced Swift-XRT position
Date
2012-03-11T21:54:08Z (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 4834 s of XRT Photon Counting mode data and 10 UVOT
images for GRB 120311B, 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 = 258.56208, -13.05144 which is equivalent
to:
RA (J2000): 17h 14m 14.90s
Dec (J2000): -13d 03' 05.2"
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 13041
Subject
GRB 120311B: Swift-BAT refined analysis
Date
2012-03-11T21:31:25Z (14 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
T. N. Ukwatta (MSU), 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), F. E. Marshall (NASA/GSFC),
D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (OSU), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
Using the data set from T-120 to T+258 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120311B (trigger #517489)
(Marshall, et al., GCN Circ. 13038). The BAT ground-calculated position is
RA, Dec = 258.551, -13.068 deg, which is
RA(J2000) = 17h 14m 12.2s
Dec(J2000) = -13d 04' 05.0"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 62%.
The mask-weighted light curve shows two nearly separated peaks, the first
starting at ~T-15 sec, peaking at ~T_0, and the minimum between the two
peaks is at ~T+5 sec. The second peak peaks at ~T+10 sec, and
returns to baseline at ~T+22 sec. T90 (15-350 keV) is 28.2 +- 5.5 sec
(estimated error including systematics).
The time-averaged spectrum from T-13.88 to T+21.63 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.96 +- 0.14. The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+9.04 sec in the 15-150 keV band
is 1.5 +- 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/517489/BA/
GCN Circular 13040
Subject
GRB 120311B: Swift-XRT observations
Date
2012-03-11T17:07:00Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
J.P. Osborne (U. Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU), G.
Tagliaferri (INAF-OAB), S. Campana (INAF-OAB) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 120311B at 15:59:18.5 UT,
3067.7 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 258.56101,
-13.05235 which is equivalent to:
RA(J2000) = 17h 14m 14.64s
Dec(J2000) = -13d 03' 08.5"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 212 arcseconds from the BAT onboard position. This position
may be improved as more data are received; the latest position is
available at http://www.swift.ac.uk/sper. This position is more than
2-sigma away from the BAT position, and so possibly unrelated to the
trigger.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.64
x 10^21 cm^-2 (Kalberla et al. 2005).
GCN Circular 13038
Subject
GRB 120311B: Swift detection of a burst
Date
2012-03-11T15:17:28Z (14 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
M. M. Chester (PSU), J. R. Cummings (NASA/UMBC),
P. D'Avanzo (INAF-OAB), C. Guidorzi (U Ferrara),
A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), D. M. Palmer (LANL),
B. Sbarufatti (INAF-OAB/PSU), E. Sonbas (NASA/GSFC/Adiyaman Univ.) and
B.-B. Zhang (PSU) report on behalf of the Swift Team:
At 15:08:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120311B (trigger=517489). Swift did not slew immediately
because of the Earth limb observing constraint.
The BAT on-board calculated location is
RA, Dec 258.501, -13.060 which is
RA(J2000) = 17h 14m 00s
Dec(J2000) = -13d 03' 34"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows two peaks
structure with a duration of about 20 sec. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~10 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+49.0
minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.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.)