GRB 151215A
GCN Circular 18691
Subject
GRB 151215A: Swift detection of a burst
Date
2015-12-15T03:14:38Z (10 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
S. L. Gibson (U Leicester), J. A. Kennea (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL),
B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf
of the Swift Team:
At 03:01:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 151215A (trigger=667392). Swift slewed to the burst
after a short delay due to observing constraints.
The BAT on-board calculated location is
RA, Dec 93.595, +35.509 which is
RA(J2000) = 06h 14m 23s
Dec(J2000) = +35d 30' 34"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve showed a single-peaked
structure with a duration of about 5 sec. The peak count rate
was ~1300 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 03:04:18.1 UT, 169.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 93.58198, 35.51503 which is equivalent
to:
RA(J2000) = 06h 14m 19.68s
Dec(J2000) = +35d 30' 54.1"
with an uncertainty of 5.1 arcseconds (radius, 90% containment). This
location is 43 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 4.02
x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 173 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 19.6 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 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.40.
Burst Advocate for this burst is S. L. Gibson (slg44 AT le.ac.uk).
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 18692
Subject
GRB151215A: P60 Optical Afterglow Candidate
Date
2015-12-15T03:50:49Z (10 years ago)
From
S. Bradley Cenko at NASA/GSFC <brad.cenko@nasa.gov>
S. B. Cenko (NASA/GSFC) reports on behalf of a larger collaboration:
We have imaged the location of GRB151215A (Gibson et al., GCN 18691) with the robotic Palomar 60 inch telescope. Observations began at 3:07 UT (~ 6 minutes after the BAT trigger) and were obtained in the r', i', and z' filters.
Just outside the XRT error circle, we find a fading source at (J2000.0) coordinates:
RA: 06:14:20.22
Dec: +35:30:57.2
Using calibration from nearby point sources, we find the object fades from i' = 17.47 +/- 0.05 mag at 3:07 UT to 18.58 +/- 0.15 mag at 3:24 UT. Thus, we believe this quite likely to be the optical afterglow of GRB151215A.
Further observations are planned.
GCN Circular 18693
Subject
GRB 151215A: Prompt enhanced Swift-XRT position
Date
2015-12-15T03:52:01Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 151215A, we find an
enhanced XRT position of the afterglow: RA, Dec: 93.5840, 35.5162 which
is equivalent to:
RA (J2000) = 06 14 20.17
Dec (J2000) = +35 30 58.3
with an uncertainty of 2.2 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/667392.
Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.
GCN Circular 18694
Subject
GRB 151215A: GROND Detection of the Optical/NIR Afterglow
Date
2015-12-15T05:03:48Z (10 years ago)
From
Philip Wiseman at MPE/Swift <wiseman@mpe.mpg.de>
P. Wiseman (MPE Garching), D. A. Kann (TLS Tautenburg), T. Schweyer,
and J. Greiner (MPE Garching) report on behalf of the GROND team:
We observed the field of GRB 151215A (Swift trigger 667392; Gibson et al.,
GCN #18691) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).
Observations started at 04:04 UT on 15/12/2015, 63 minutes after the GRB
trigger, and are continuing. They were performed at an average seeing of
1.40" and at an average airmass of 2.5.
We found a single point source within the 2.2" Swift-XRT error circle
reported by Evans et al. (GCN #18693) and consistent with that of Cenko
GCN #18692), at:
RA (J2000.0) = 93.58416 = 06:14:20.2
Dec. (J2000.0) = +35.51596 = +35:30:57.5
with an uncertainty of 0.3" in each coordinate.
Based on the first 3.3 min of total exposures in g'r'i'z' and 3.0 min in
JHK, we estimate preliminary magnitudes (AB system) of
g' = 21.81 +/- 0.09 mag,
r' = 20.80 +/- 0.05 mag,
i' = 20.44 +/- 0.05 mag,
z' = 20.36 +/- 0.07 mag,
J = 19.6 +/- 0.2 mag,
H = 19.8 +/- 0.5 mag, and
K = 18.4 +/- 0.4 mag.
Given magnitudes are calibrated against SDSS 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 (Schlafly & Finkbeiner et al. 2011).
GCN Circular 18695
Subject
GRB 151215A: Enhanced Swift-XRT position
Date
2015-12-15T06:15:51Z (10 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.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 2236 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 151215A, 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 = 93.58409, +35.51608 which is equivalent
to:
RA (J2000): 06h 14m 20.18s
Dec (J2000): +35d 30' 57.9"
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 18696
Subject
GRB 151215A: NOT spectroscopy and redshift
Date
2015-12-15T10:15:44Z (10 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
D. Xu (NAOC/CAS), N. R. Tanvir (Univ. Leicester), D. Malesani
(DARK/NBI), J. P. U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), J.
Saario (NOT and Univ. Turku) report on behalf of a larger collaboration:
We observed the optical afterglow (Cenko, GCN 18692; Wiseman et al., GCN
18694) of GRB 151215A (Gibson et al., GCN 18691) using the Nordic
Optical Telescope (NOT) equipped with the AlFOSC camera and spectrograph.
The optical afterglow is clearly visible in our images, and we measure
its brightness on Dec 15.160 UT (0.81 hr after the GRB) to be R = 20.07
+- 0.02 (Vega, assuming R = 16.31 for the USNO star at RA = 06:14:19.93,
Dec = +35:31:06.0).
A sequence of three spectra of 1200 s each was carried out starting on
Dec 15.176 UT (1.2 hr after the trigger), covering the wavelength range
3200-9000 AA.
A wide trough is visible superimposed on the afterglow continuum,
indicating Lyalpha absorption from neutral hydrogen. We also detect
several narrow absorption features, which we interpret as due to, e.g.,
Si II, O I, Al II, all at a common redshift of z = 2.59. A preliminary
fit to the Lyalpha profile yields an HI column density of 3x10^21 cm^-2,
though establishing the system as a DLA.
GCN Circular 18697
Subject
GRB 151215A: MASTER early OT detection and light curve
Date
2015-12-15T12:19:35Z (10 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
E. Gorbovskoy, V. Lipunov, N.Tyurina, D. Vlasenko, V.Kornilov,
P.Balanutsa, A.Kuznetsov, D. Vlasenko
Lomonosov Moscow State University, Sternberg Astronomical Institute
O. Gress, K. Ivanov, N.M. Budnev, V.A. Poleshchuk, S.A. Yazev
Irkutsk State University
V.Yurkov, Yu.Sergienko, A.Gabovich, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk
report on behalf of the MASTER Team:
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru,
Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010,
34917111) located in IAC was pointed to the GRB151215A (Gibson et al.
GCN 18691) 18 sec after notice time and 33 sec after trigger time at 2015-12-15 03:02:05
UT with 10s exposition in two perpendicular polarization planes.
We detect OT (Cenko et al GCN 18691, Wiseman et al. GCN 18694) in first
image with magnitude 17.8 +- 0.5 at a growing stage (midle time 38 sec
after trigger).
We definetely see OT on all images till 1500-th second.
The GRB optical light curve have a maximum at third image (110 s after
triger time) with 17.0 +- 0.1 mag.
The automatic light curve in one polarization available here
http://master.sai.msu.ru/static/GRB151215A_v1.png
All magnitudes are unfiltered (0.2B+0.8R) with respect to number USNO B1.0
stars.
This is preliminary results.
The message may be cited.
GCN Circular 18698
Subject
GRB151215A: Swift/UVOT detection
Date
2015-12-15T16:28:33Z (10 years ago)
From
Massimiliano de Pasquale at IASF-Palermo <m.depasquale@ucl.ac.uk>
M. De Pasquale (UCL-MSSL) and S. L. Gibson (U Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 151215A
174 s after the BAT trigger (Gibson et al., GCN Circ. 18691).
We detect the optical afterglow of GRB151215A within the XRT error
circle (Evans et al. GCN Circ. 18695), in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 06:14:20.25 = 93.58438 (deg.)
Dec (J2000) = +35:30:57.4 = 35.51595 (deg.)
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).
The position of this source is consistent with those given by Cenko et al.
(GCN Circ. 18692) and GROND (Wiseman et al. GCN Circ. 18694).
There is no detection in UVOT uv filters, which is congruous with
the redshift z=2.6 of the event (Xu et al., GCN circ. 18696).
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
white (Finding Chart) 174 323 147 19.05 �� 0.14
white 531 2586 362 20.59 �� 0.19
v 408 2636 253 19.67 �� 0.35
b 507 2561 233 20.85 �� 0.42
u 482 2536 233 >20.3
w1 458 2512 233 >19.9
m2 433 2651 225 >19.6
w2 384 2612 253 >19.9
The magnitudes in the table are not corrected for the substantial Galactic
extinction due to the reddening of E(B-V) = 0.39 in the direction of the
burst
(Schlegel et al. 1998).
--
Dr. Massimiliano De Pasquale
Research associate - Swift UVOT scientist
Mullard Space Science Laboratory, University College London
GCN Circular 18699
Subject
GRB 151215A: Swift-BAT refined analysis
Date
2015-12-15T22:29:18Z (9 years ago)
From
Tilan Ukwatta at LANL <tilan.ukwatta@gmail.com>
J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC),
N. Gehrels (GSFC), S. L. Gibson (U Leicester)
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-240 to T+963 sec from the recent
telemetry downlink, we report further analysis of BAT
GRB 151215A (trigger #667392) (Gibson, et al., GCN
Circ. 18691). The BAT ground-calculated position is
RA, Dec = 93.622, 35.529 deg which is
RA(J2000) = 06h 14m 29.3s
Dec(J2000) = +35d 31' 45.0"
with an uncertainty of 2.8 arcmin, (radius, sys+stat,
90% containment). The partial coding was 51%.
The mask-weighted light curve shows a multi-peak episode
starting ~T-15 sec, highest peak at ~T+0 sec, and the
episode ends around ~T+5 sec. T90 (15-350 keV)
is 17.8 +- 1.0 sec (estimated error including systematics).
The time-averaged spectrum from T-15.46 to T+3.13 sec is
best fit by a simple power-law model. The power law index
of the time-averaged spectrum is 1.99 +- 0.33. The fluence
in the 15-150 keV band is 3.1 +- 0.7 x 10^-07 erg/cm2.
The 1-sec peak photon flux measured from T-0.16 sec in
the 15-150 keV band is 1.6 +- 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/667392/BA/
GCN Circular 18700
Subject
GRB 151215A: Swift-XRT refined Analysis
Date
2015-12-16T03:14:03Z (9 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. D'Elia
(ASDC), A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), L.M. McCauley
(PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU) and S.L. Gibson
report on behalf of the Swift-XRT team:
We have analysed 7.4 ks of XRT data for GRB 151215A (Gibson et al. GCN
Circ. 18691), from 180 s to 35.7 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 18693).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.88 (+0.07, -0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.21 (+0.18, -0.17). The
best-fitting absorption column is consistent with the Galactic value
of 4.0 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum is 3.5 x 10^-11 (6.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 4.0 x 10^21 cm^-2
Intrinsic column: 4 (+/-12) x 10^21 cm^-2 at z=2.59
Photon index: 2.21 (+0.18, -0.17)
If the light curve continues to decay with a power-law decay index of
0.88, the count rate at T+24 hours will be 3.6 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-13 (2.2 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00667392.
This circular is an official product of the Swift-XRT team.
GCN Circular 18702
Subject
GRB 151215A: MITSuME Akeno optical upper limits
Date
2015-12-16T11:13:41Z (9 years ago)
From
Taketoshi Yoshii at Tokyo Tech <yoshii.t.ac@m.titech.ac.jp>
Y.Muraki, T.Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana,
Y.Yano, S.Harita, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 151215A (S. L. Gibson et al., GCN Circular #18691) 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 2015-12-15 16:23:38 UT (~13.4 h after the burst).
We did not find any new point source within Swift/XRT circle in all three bands.
We obtained following limits for the magnitudes.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------
48230 17:48:09 5070 > 20.9 > 20.6 > 19.6
-------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 18703
Subject
GRB151215A: Early optical light curve from pt5m, La Palma
Date
2015-12-16T15:03:14Z (9 years ago)
From
Liam K Hardy at U of Shffield <liam.hardy@sheffield.ac.uk>
L. K. Hardy (Sheffield), S. P. Littlefair (Sheffield),
V. S. Dhillon (Sheffield, IAC), T. Butterley (Durham) and
R. W. Wilson (Durham) report:
The automated robotic telescope 'pt5m' (Hardy et al.
2015, MNRAS 454, 4316) on La Palma observed the field
of GRB 151215A (Gibson et al., GCN 18691) starting
at 03:02:42 UT on Dec 15, 53 seconds after the alert
notice release and 74 seconds after the GRB detection.
Observations comprised of 59 x 60-second exposures in
the Johnson/Cousins R-band with approximately 6-seconds
dead time between images. The final image was taken 65
minutes after the first.
We detect the optical counterpart to the GRB and observe a
rapidly declining light curve. Photometry is performed using
historical instrumental zeropoints. We measure an initial
magnitude of R = 17.13 +/- 0.04 (2 minutes after the GRB) and
a final magnitude of R = 20.8 +/- 0.7 (67 minutes after the GRB).
The light curve is available at:
http://slittlefair.staff.shef.ac.uk/images/grb151215.png
GCN Circular 18707
Subject
GRB151215A: Continued P60 Observations
Date
2015-12-17T15:30:18Z (9 years ago)
From
S. Bradley Cenko at NASA/GSFC <brad.cenko@nasa.gov>
S. B. Cenko (NASA/GSFC) and D. A. Perley (DARK/NBI) report on behalf of a larger collaboration:
We imaged the field of the optical afterglow (Cenko et al., GCN 18692) of GRB151215A (Gibson et al., GCN 18691) with the robotic Palomar 60 inch telescope. Observations were obtained in the r', i', and z' filters beginning at 3:41 UT on 16 December 2015 (1.0 d after the Swift trigger). We do not detect any emission at the location of the afterglow in any filter. Using nearby point sources from SDSS for calibration, we calculate an upper limit of i' > 21.7 mag at a mean epoch of 1.04 d after the burst.
GCN Circular 18708
Subject
GRB 151215A: TSHAO optical observations
Date
2015-12-17T17:16:14Z (9 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
E. Mazaeva (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Kusakin
(Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI)
report on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 151215A (Gibson et al., GCN 18691) with
Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory
starting on Dec. 15 (UT) 16:47:23. We obtained several images in R
filter. The afterglow (Cenko, GCN 18692) is detected in a combined
image. Preliminary photometry of the afterglow is following
Date UT start t-T0 Filter Exp. OT Err
(mid, days) (s)
2015-12-15 16:47:23 0.61190 R 21*300 22.1 0.3
The photometry is based on nearby SDSS stars.
GRB 151215A
observatory TSHAO
date 2015-12-15
UT start 16:47:23.69
t-T0 0.61190 d
exptime 21*300 s
filter R
OT 22.07 +/- 0.38 (�������������������� ��������������)
uplim 22.4
fwhm 2.4 "
GCN Circular 19001
Subject
GRB 151215A: TAROT Calern observatory very early optical detection
Date
2016-02-07T22:36:40Z (9 years ago)
From
Alain Klotz at IRAP-CNRS-OMP <Alain.Klotz@free.fr>
Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.) report:
We imaged the field of GRB 151215A detected by SWIFT
(trigger 667392) with the TAROT robotic telescope (D=25cm)
located at the Calern observatory, France.
The observations started 31.6s after the GRB trigger
(17.7s after the notice). The elevation of the field decreased
from 56 degrees above horizon and weather conditions
were good but images were slightly unfocused.
The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
Due to the unfocused condition, we took time to
reprocess the image to extract the magnitude of the
optical transient discovered by Cenko et al. (GCNC 18692):
t1(s) t2(s) Rmag d_Rmag
31.6 44.5 17.3 0.5
44.5 91.6 16.7 0.3
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.