GRB 120308A
GCN Circular 13031
Subject
GRB 120308A : LOAO optical observation
Date
2012-03-10T15:26:15Z (14 years ago)
From
Minsung Jang at Seoul National U <rigel103@snu.ac.kr>
Jang, M., Im, M. (SNU), & Urata, Y. (NCU)
We observed GRB 120308A (Baumgartner et al., GCN 13017)
in R, I-bands with a 1 m telescope at Mt. Lemmon, Arizona, U.S.
The obsevation started at 10:51:23 2012-03-08 UT, ~ 4.6 hours
after the burst alert.
We alternatively took 6 frames for each filter with the exposure time, 300s.
We found a optical afterglow candidate in the stacked I image
with a preliminary magnitude, I ~ 18.7 +/- 0.12 mag
at mid-point time, 17274 sec after the burst alert
on the enhanced XRT position (Evans et al., GCN13023).
However, no afterglow candidate was found in the stacked R image.
We thank the LOAO operator, J. Yoon for this observation.
GCN Circular 13030
Subject
GRB 120308A: RTT150 optical observations
Date
2012-03-10T08:39:23Z (14 years ago)
From
Rodion Burenin at IKI, Moscow <rodion@hea.iki.rssi.ru>
I. Bikmaev, R.Zhuchkov , N. Sakhibullin (Kazan Federal University),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Khamitov, Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.)
report:
The field of GRB 120308A (Baumgartner et al., GCN 13017) was observed
with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK
National Observatory, Turkey) on March 08, 2012, UT(mean)= 22:35,
approximately 16 hours after the burst. A serie of exposures by 300
sec each in Rc filter was obtained at moderate weather conditions.
We marginaly detected optical source at the position of OT (Virgili et
al., GCN 13018) and estimated its Rc ~ 22.5 mag in our combined image.
GCN Circular 13028
Subject
GRB 120308A: 1.23m CAHA I-band observations
Date
2012-03-10T03:25:36Z (14 years ago)
From
Javier Gorosabel at IAA-CSIC <jgu@iaa.es>
J. Gorosabel (IAA-CSIC), P. Kubanek (FZU, Praha), M. Jelinek (IAA-CSIC), report on behalf of a larger collaboration:
"We imaged the field of the Swift GRB 120308A (Baumgartner et al., GCN Circ. 13017)
with the 1.23m Calar Alto telescope. The observations were carried out in the I-band
on March 8.93056--9.18766 UT (16.1--22.3 hours post burst). No optical source brighter
than I=20.8 was found consistent with the optical afterglow coordinates (Virgili et al.,
GCN Circ. 13018; Kuin et al., GCN Circ. 13025)."
GCN Circular 13027
Subject
GRB 120308A: Further PAIRITEL NIR Observations
Date
2012-03-09T23:18:17Z (14 years ago)
From
Adam Morgan at U.C. Berkeley <qmorgan@gmail.com>
A. N. Morgan, and J. S. Bloom (UC Berkeley) report:
We continued to observe the field of GRB 120308A (Baumgartner et al.,
GCN 13017) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona.
The source faded significantly since our first epoch (Morgan et al.,
GCN 13020), suggesting a temporal decay index of approximately 1.0
during our observations.
The preliminary photometry yields:
post burst
t_mid (hr) exp.(hr) filt mag m_err
1.55 0.50 J 17.70 0.18
1.55 0.50 H 16.81 0.21
1.55 0.50 Ks 16.00 0.21
5.08 2.09 J 18.92 0.25
5.08 2.09 H >18.2 3sigUL
5.08 2.09 Ks >17.3 3sigUL
All magnitudes are given in the Vega system, calibrated to 2MASS. No
correction for Galactic extinction has been made to the above reported
values. No further observations are planned.
GCN Circular 13026
Subject
GRB120308A: MITSuME Ishigakijima Optical Upper Limits
Date
2012-03-09T07:46:33Z (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 120308A (Baumgartner et al., GCNC 13017)
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 012-03-08 12:48:40 UT, (~6.6 h after the burst).
We did not find any new point source within the enhanced XRT error
circle (Evans et al., GCNC 13023) in all the three bands.
We could not detect the previously reported afterglow (Virgili et al., GCNC 13018).
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 Ic
-----------------------------------------------------
0.30659 13:35:07 2220.0 >19.4 >19.4 >19.0
-----------------------------------------------------
T0+ : Elapsed time after the burst [day]
T-EXP: Total Exposure time [sec]
GCN Circular 13025
Subject
GRB 120308A: Swift/UVOT Detection
Date
2012-03-08T19:32:24Z (14 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (MSSL-UCL) and W. H. Baumgartner (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 120308A
158 s after the BAT trigger (Baumgartner et al., GCN Circ. 13017).
A source consistent with the optical position reported by Virgili et al.
(GCN Circ. 13018) is detected in the initial UVOT exposures, but only
in the v and b band. In u there is no evidence for a source, which
suggests that the source is at a redshift of z < 4, and in case there
is no contamination of dust, z ~ 3.2.
The best UVOT position is
RA(J2000) = 14h 36m 20.05s
Dec(J2000) = 79d 41' 12.2"
with an uncertainty of 0.55" (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 463 483 20 17.02 +/- 0.17
b 413 432 19 17.65 +/- 0.13
u 158 7690 1020 >20.9
w1 512 13962 1165 >21.3
m2 636 13409 1415 >21.3
w2 438 8103 646 >21.5
b 711 730 19 18.40 +/- 0.25
v 761 1082 39 18.14 +/- 0.29
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 13024
Subject
GRB 120308A: Swift-XRT refined Analysis
Date
2012-03-08T18:30:04Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
C. Pagani (U. Leicester), A. Maselli (INAF-IASFPA), V. Mangano
(INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU), J.A. Kennea
(PSU), M.C. Stroh (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester) and W.H. Baumgartner report on behalf of the Swift-XRT team:
We have analysed 12 ks of XRT data for GRB 120308A (Baumgartner et al.
GCN Circ. 13017), from 82 s to 30.0 ks after the BAT trigger. The data
comprise 190 s in Windowed Timing (WT) mode (the first 9 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 Evans et
al. (GCN. Circ 13023).
The late-time light curve (from T0+5.8 ks) can be modelled with a
power-law decay with a decay index of alpha=1.29 (+/-0.09).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 3.17 (+0.10, -0.09). The
best-fitting absorption column is 1.90 (+0.16, -0.15) x 10^21 cm^-2,
in excess of the Galactic value of 2.9 x 10^20 cm^-2 (Kalberla et al.
2005). The PC mode spectrum has a photon index of 1.61 (+0.09, -0.08)
and a best-fitting absorption column of 4.8 (+2.1, -1.9) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum is 4.3 x 10^-11 (4.7 x 10^-11) erg cm^-2
count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 4.8 (+2.1, -1.9) x 10^20 cm^-2
Galactic foreground: 2.9 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.61 (+0.09, -0.08)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00517234.
This circular is an official product of the Swift-XRT team.
GCN Circular 13023
Subject
GRB 120308A: Enhanced Swift-XRT position
Date
2012-03-08T14:45:03Z (14 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1980 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 120308A, 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 = 219.08506, +79.68651 which is equivalent
to:
RA (J2000): 14h 36m 20.41s
Dec (J2000): +79d 41' 11.4"
with an uncertainty of 1.9 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 13022
Subject
GRB 120308A: Swift-BAT refined analysis
Date
2012-03-08T13:50:31Z (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), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
M. Stamatikos (OSU), G. Sato (ISAS), 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 120308A (trigger #517234)
(Baumgartner, et al., GCN Circ. 13017). The BAT ground-calculated position is
RA, Dec = 219.123, 79.674 deg, which is
RA(J2000) = 14h 36m 29.5s
Dec(J2000) = +79d 40' 25.7"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 97%.
The mask-weighted light curve shows a mostly smooth peak starting at ~T-30 sec,
peaking at ~T+1 sec, and ending at ~T+70 sec. T90 (15-350 keV) is
60.6 +- 17.1 sec (estimated error including systematics).
The time-averaged spectrum from T-24.15 to T+58.20 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.71 +- 0.13. The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.62 sec in the 15-150 keV band
is 0.6 +- 0.1 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/517234/BA/
GCN Circular 13021
Subject
GRB 120308A: IAC80 I-band observations
Date
2012-03-08T09:31:39Z (14 years ago)
From
Javier Gorosabel at IAA-CSIC <jgu@iaa.es>
J. Gorosabel (IAA-CSIC) and R. Gimeno (IAC), report on behalf of a larger collaboration:
"We observed the field of GRB 120308A (Baumgartner et al., GCNC 13017) with the 82cm IAC80 telescope at the Observatorio del Teide, Tenerife, Spain. The observations were carried in the I-band on March 8.27260--8.28075 UT (18.91-30.65 minutes post burst) with a total exposure time of 5x120s. A preliminary analysis of the individual and combined images detect clearly the optical/NIR afterglow (Virgili et al. GCN 13018, Elenin et al. GCN 13019, Morgan et al. GCN 13020) with a magnitude of I~16.8 with respect to the USNO B1.0 catalogue."
GCN Circular 13020
Subject
GRB 120308A: PAIRITEL NIR observations
Date
2012-03-08T08:46:02Z (14 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 120308A (Baumgartner et al., GCN 13017)
with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations
began at 2012-Mar-08 07h14m27s UT, ~1.0 hours after the Swift Trigger,
under moderate airmass (~1.7). In mosaics (effective exposure time
of 0.39 hours) taken simultaneously in the J, H, and Ks filters, we
detect the afterglow (Virgili et al., GCN 13018, Elenin et al., GCN
13019) at the Liverpool position (Virgili et al., GCN 13018).
The preliminary photometry yields:
post burst
t_mid (hr) exp.(hr) filt mag m_err
1.44 0.39 J 17.71 0.21
1.44 0.39 H 16.74 0.22
1.44 0.39 Ks 16.06 0.25
Observations are ongoing. 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 13019
Subject
GRB 120308A: confirmation of the optical afterglow
Date
2012-03-08T08:06:37Z (14 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
L. Elenin (KIAM), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf
of larger GRB follow-up collaboration:
The 0.45-m telescope of ISON-NM observatory robotically followed up the
field of the Swift GRB 120308A (Baumgartner et al., GCN 13017 ) on March
8, 06:16:55, i.e. 3.3 minutes after burst trigger. In the first frame of 30
s exposure we do not detect the optical afterglow (Virgili et al., GCN
13018 ) up to R~16m. However in a stacked several first images of 1800 s
exposure we clearly detect new source in coordinates 14 36 19.95 +79 41 12.3
which are coincide with coordinates of the optical afterglow (Virgili et
al., GCN 13018 ). The magnitude of the source at (UT) 06:38:10 (middle
time) is R~17.30m. All images are unfiltered and calibrated against
USNO-B1.0 R2 field stars.
All results are preliminary. Observation is continuing.
GCN Circular 13018
Subject
GRB 120308A: Liverpool Telescope optical afterglow candidate
Date
2012-03-08T07:16:52Z (14 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
F. Virgili (LJMU), J. Japelj, (U. Ljubljana), C. Guidorzi (U. Ferrara)
on behalf of a larger collaboration report:
"The 2-m Liverpool Telescope robotically followed up GRB 120308A
(SWIFT trigger 517234) 15.5 min after the GRB trigger time.
The automatic "detection mode" procedure detected an uncatalogued
afterglow candidate within the XRT error circle at:
14:36:19.97 +79:41:12.4 (J2000)
with magnitude r' = 17.2 mag (vs USNOB1) 18.6 min after the burst.
Observations and analysis are ongoing.
GCN Circular 13017
Subject
GRB 120308A: Swift detection of a burst
Date
2012-03-08T06:29:58Z (14 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
M. M. Chester (PSU), V. D'Elia (ASDC), A. Y. Lien (NASA/GSFC/ORAU),
C. B. Markwardt (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the
Swift Team:
At 06:13:38 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120308A (trigger=517234). Swift slewed immediately to the burst.
The BAT on-board calculated location is RA, Dec 219.078, +79.703 which is
RA(J2000) = 14h 36m 19s
Dec(J2000) = +79d 42' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a broad peak
structure with a duration of about ~30 sec. The peak count rate
was ~500 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 06:15:11.3 UT, 92.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 219.08492, 79.68629 which
is equivalent to:
RA(J2000) = 14h 36m 20.38s
Dec(J2000) = +79d 41' 10.6"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 60 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. We
cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.89
x 10^20 cm^-2 (Kalberla et al. 2005).
The initial flux in the 2.5 s image was 1.17e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 250 seconds with the U filter starting
157 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 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.03.
Burst Advocate for this burst is W. H. Baumgartner (wayne 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.)