GRB 151228A
GCN Circular 18731
Subject
GRB 151228A: Swift detection of a short burst
Date
2015-12-28T03:14:53Z (10 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (NASA/UMBC) and K. L. Page (U Leicester) report on
behalf of the Swift Team:
At 03:05:12 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 151228A (trigger=668543). Swift did not slew to the burst.
The BAT on-board calculated location is
RA, Dec 214.004, -17.689, which is
RA(J2000) = 14h 16m 01s
Dec(J2000) = -17d 41' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows a single spike
structure with a duration of about 0.6 sec. The peak count rate
was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift cannot slew to the BAT position.
There will thus be no XRT or UVOT data for this trigger.
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.)
GCN Circular 18736
Subject
GRB 151228A: Fermi GBM observation
Date
2015-12-28T16:41:59Z (10 years ago)
From
Peter Veres at UAH <veresp@gmail.com>
Elisabetta Bissaldi (Politecnico di Bari), Binbin Zhang (UAH) and
Peter Veres (UAH)
report on behalf of the Fermi GBM Team:
"At 03:05:12.46 UT on 28 December 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 151228A (trigger 472964716 / 151228129),
which was also detected by the Swift/BAT
(Ukwatta et al. 2015, GCN 18731).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 117 degrees.
The GBM light curve consists of a single peak
with a duration (T90) of about 0.26 s (50-300 keV).
The time-averaged spectrum from T0-0.06 s to T0+0.32 s is
well fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.41 +/- 0.23 and
the cutoff energy, parameterized as Epeak, is 747 +/- 193 keV.
The event fluence (10-1000 keV) in this time interval is
(9.2 +/- 0.8)E-7 erg/cm^2. The 64 ms peak photon flux measured
starting from T0-0.06 s in the 10-1000 keV band
is 12.4 +/- 2.0 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."
GCN Circular 18746
Subject
GRB 151228A: T60 observations
Date
2015-12-29T07:59:13Z (10 years ago)
From
Eda Sonbas at NASA/GSFC <edasonbas@gmail.com>
Sonbas, E. (Adiyaman Univ.), Parmaksizoglu, M. (TUG), Guver, T. (Istanbul
Univ.), Gogus, E. (Sabanci Univ.), Dindar, M., Kirbiyik, H. (TUG) on behalf
of a larger collaboration.
We observed the field of GRB 151228A (Ukwatta et al., GCN #18731) with the
0.60 meter T60 telescope (TUBITAK National Observatory, Antalya - Turkey),
starting on December 28, 03:06:43.45 UT (~ 90 sec after the trigger). We
obtained 3 x 60 s + 2 x 20 s exposures with R filters under good weather
conditions.
We do not detect an optical afterglow within the reported BAT error circle
down to a limiting magnitude of >~17 (2-sigma) in the combined R band image.
We thank to TUBITAK National Observatory for a partial support in using T60
telescope with project number 13DT60-539 and technical support.
GCN Circular 18747
Subject
GRB 151228A: MITSuME Akeno optical upper limits
Date
2015-12-29T09:15:22Z (10 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
Y.Saito, T.Fujiwara, T. Yoshii, Y. Tano, Y. Tachibana,
Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 151228A (T. N. Ukwatta et al., GCN Circular #18731) with the
optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope of Akeno Observatory, Yamanashi, Japan.
The observation started on 2015-12-28 19:25:49 UT (~16.3 h after the burst).
We did not find any new point source within BAT circle in all three bands.
We obtained following limits for the magnitudes.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
--------------------------------------------------------------------------------------
58837 20:04:32 4200 > 20.0 > 20.0 > 19.3
---------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 18754
Subject
GRB 151228A: Swift-BAT refined analysis
Date
2015-12-29T15:37:40Z (10 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry downlinks,
we report further analysis of BAT GRB 151228A (trigger #668543)
(Ukwatta, et al., GCN Circ. 18731). The BAT ground-calculated position is
RA, Dec = 214.017, -17.665 deg, which is
RA(J2000) = 14h 16m 04.0s
Dec(J2000) = -17d 39' 52.7"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a single spike starting at ~T-0.05,
peaking at ~T+0.03, and ending at ~T+0.3. T90 (15-350 keV) is
0.27 +- 0.01 sec (estimated error including systematics).
The time-averaged spectrum from T-0.036 to T+0.276 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
0.85 +- 0.20. The fluence in the 15-150 keV band is 8.4 +- 1.1 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.38 sec in the 15-150 keV band
is 0.9 +- 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/668543/BA/
GCN Circular 18770
Subject
GRB 151228A: Swift-XRT refined Analysis
Date
2015-12-30T13:33:24Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N.
Burrows (PSU), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), C. Pagani
(U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester) and T.N. Ukwatta report on behalf of the Swift-XRT team:
We have analysed xx ks of XRT data for GRB 151228A (Ukwatta et al. GCN
Circ. 18731), from xx to 0 s after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. We cannot determine at the
present time whether the source is fading.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00668543.
This circular is an official product of the Swift-XRT team.
GCN Circular 18772
Subject
GRB 151228A: Correction to GCN 18770
Date
2015-12-30T13:49:06Z (10 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:
We apologise for the incomplete nature of GCN 18770, which was
automatically sent out in error. The correct information is given below:
We have analysed 2.2 ks of XRT data for GRB 151228A (Ukwatta et al., GCN
Circ. 18731), from 178.6 to 196.5 ks after the BAT trigger. The data are
entirely in Photon Counting (PC) mode. No X-ray source is detected in or
near to the BAT refined error circle (Barthelmy et al., GCN Circ. 18754),
to a 3-sigma upper limit of 7x10^-3 count s^-1, corresponding to an
approximate observed flux of 3x10^-13 erg cm^-2 s^-1.
This circular is an official product of the Swift-XRT team.