GRB 170202A
GCN Circular 20575
Subject
GRB 170202A: Swift detection of a burst with an optical afterglow
Date
2017-02-02T18:53:46Z (8 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC),
A. Cholden-Brown (PSU), J. A. Kennea (PSU),
H. A. Krimm (CRESST/NSF/USRA), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Swift Team:
At 18:28:02 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170202A (trigger=736407). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 152.529, +5.002 which is
RA(J2000) = 10h 10m 07s
Dec(J2000) = +05d 00' 06"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows 4 main peaks
with a total duration of about 40 sec. The peak count rate
was ~4800 counts/sec (15-350 keV), at ~16 sec after the trigger.
The XRT began observing the field at 18:29:14.8 UT, 72.5 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 152.51422, 5.01213 which
is equivalent to:
RA(J2000) = 10h 10m 03.41s
Dec(J2000) = +05d 00' 43.7"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 64 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. No
spectrum from the promptly downlinked event data is yet available to
determine the column density.
The initial flux in the 2.5 s image was 2.21e-09 erg cm^-2 s^-1 (0.2-10
keV).
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 83 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 10:10:03.49 = 152.51455
DEC(J2000) = +05:00:41.8 = 5.01161
with a 90%-confidence error radius of about 0.75 arc sec. This position is 0.5
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.46 with a 1-sigma error of about 0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02.
Burst Advocate for this burst is J. L. Racusin (judith.racusin AT 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.)
GCN Circular 20576
Subject
GRB 170202A : Xinglong TNT optical observation
Date
2017-02-02T20:09:09Z (8 years ago)
From
L.P. Xin at NAOC <xlp@nao.cas.cn>
L. P. Xin, W. X, Li, J. Y. Wei, Y. L. Qiu, J. S. Deng,
J. Wang, X. H. Han, C. Wu and H. L. Li report:
We observed GRB 170202A (Racusin et al. GCN 20575) with
Xinglong 0.8-m TNT telescope at 18:29:00 UT, 58 sec after the burst.
The optical afterglow (Racusin et al. GCN 20575 ) was detected
in our white and R-band images, with a coordinate of
RA=10:10:03.48
DEC=05:00:42.29
Epoch=J2000
Which is consistent with report by UVOT detection ( Racusin et al. GCN 20575).
The brightness of the optical afterglow is about 18.9 mag
at the mid time of 69 sec afer the burst,
calibrated by the USNO B1.0 star (RA=10:10:03.29 DEC=04:59:37.4 R2=14.95mag).
The observations are continuous.
The message may be cited.
GCN Circular 20577
Subject
GRB 170202A: Mini-MegaTORTORA upper limits
Date
2017-02-02T20:42:54Z (8 years ago)
From
Sergey Karpov at SAO RAS <karpov@sao.ru>
S.Karpov, G.Beskin (SAO RAS and Kazan Federal University, Russia), S.Bondar,
E.Ivanov, E.Katkova, N.Orekhova, A.Perkov (OJS RPC PSI, Russia), A.Biryukov
(SAI MSU and Kazan Federal University, Russia), V.Sasyuk (Kazan Federal
University, Russia)
Mini-MegaTORTORA nine-channel wide-field monitoring system with high
temporal resolution responded to the BAT trigger and observed the position
of GRB 170702A (Racusin et al. GCN 20575) since 2017-02-02 18:28:50 UT
(T+47.8 s) and until 2017-02-02 18:39:04 UT (T + 662.0 s). The system
acquired a series of 5 s exposure frames with all 9 channels pointed to the
object location in white light, with and without polarimetric filters
installed. No transient object is detected over this interval, with
detection limit on a single frame V=13.0 mag. Co-adding 9 simultaneous
frames improves the detection limit to V=14.0 mag at the mid-time of first
exposure (Tmid = T+50.3 s, 5 s exposure).
Mini-MegaTORTORA belongs to Kazan Federal University and is located at
Special Astrophysical Observatory near Russian 6-m telescope.
The message may be cited.
GCN Circular 20578
Subject
GRB 170202A: MASTGlobal ER-Net bright OT nonmonotonic light curve
Date
2017-02-02T21:28:25Z (8 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, N.Tyurina, E. Gorbovskoy, V.V.Kornilov,
D.Kuvshinov, P.Balanutsa, A.Kuznetsov, V.V.Chazo, A.V.Krylov, I.Gorbunov
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University
V.Yurkov, A. Gabovich, Yu.Sergienko
Blagoveschensk Educational State University, Blagoveschensk
A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik
Kislovodsk Solar Station of the Pulkovo Observatory
K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk, O. Ershova
Irkutsk State University
R. Podesta, Carlos Lopez and Federico Podesta
Observatorio Astronomico Felix Aguilar (OAFA)
Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Blagoveschensk was pointed to the GRB170202.77 37 sec after
notice time and 49 sec after trigger time at 2017-02-02 18:28:58 UT. On
our first (10s exposure) set we found 1 optical transient within SWIFT
error-box (ra=152.525 dec=5.00139 r=0.05) brighter then 16.5
RA, DEC = 10h 10m 03s.5 , + 5d 0m 41s.8
Mag = 16.2
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Tunka was pointed to the GRB170202.77 69 sec after notice time
and 85 sec after trigger time at 2017-02-02 18:29:33 UT. On our first (20s
exposure) set we found optical transient within SWIFT error-box
(ra=152.525 dec=5.00111 r=0.05) brighter then 17.8.
MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in SAAO was pointed to the GRB170202.77 4070 sec after notice
time and 4082 sec after trigger time at 2017-02-02 19:36:11 UT. On our
18-th (180s exposure) set we found optical transient within SWIFT
error-box (ra=152.525 dec=5.00111 r=0.05) brighter then 17.00.
MASTER-Amur light curve is
available at http://master.sai.msu.ru/static/OT/MASTERGRB170202A.jpg
GCN Circular 20579
Subject
GRB 170202A: LCO Sutherland observations
Date
2017-02-02T22:32:33Z (8 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc
(U. Nova Gorica), C.G. Mundell (U. Bath) on behalf of a large
collaboration report:
We observed Swift GRB 170202A (Racusin et al. GCN 20575) on February 02,
from 21:19 UT (2.8 hours since the GRB) with 1-m LCO telescope units in
Sutherland with SDSS r and i filters. We detect the optical afterglow
(Racusin et al. GCN 20575; Xi et al. GCN 20576; Lipunov et al. GCN
20578) at the Swift-UVOT position with the following values:
Mid Time Exposure Filter Magnitude (AB)
(hours) (s)
-------------------------------------------------------
2.9 4x120 SDSS-R 19.65 +- 0.15
3.0 4x120 SDSS-I 19.32 +- 0.18
-------------------------------------------------------
as calibrated against nearby SDSS sources.
GCN Circular 20580
Subject
GRB 170202A: Zadko observatory - Gingin optical observations
Date
2017-02-02T22:55:17Z (8 years ago)
From
Alain Klotz at IRAP-CNRS-OMP <Alain.Klotz@free.fr>
A. Klotz, D. Turpin (IRAP-CNRS-OMP),
D. Macpherson (UWA/ICRAR), D. Coward (UWA),
M. Boer, R. Laugier (UNS-CNRS-OCA),
Gendre B. (UVI - Etelman Obs.),
A. Williams (PO-UWA), R. Martin (PO-UWA)
report:
We imaged the field of GRB 170202A detected by SWIFT
(trigger 736407) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.
The observations started 58s after the GRB trigger
(42s after the notice). The elevation of the field decreased from
51 degrees above horizon and weather conditions
were very good.
The first image is trailed with a duration of 60.0s
(see the description in Klotz et al., 2006, A&A 451, L39).
We detect the optical transcient described by Racusin et
al. (GCNC 20575), Xin et al. (GCNC 20576) and Lipunov et
al. (GCNC 20578). We calibrated magnitudes using the same
reference star than Xin et al. (GCNC 20576).
The afterglow increases slowly and continuously from 73s
(i.e. the limiting magnitude R~19) until 400s (R=16.5).
After 550s the flux start to decrease with a standard
temporal decay alpha=-1 until 5000s (R=19).
Extrapolation with this rate gives R=22.3 at t0+1day.
So we encourage to perform spectrometry.
N.B. Zadko Magnitudes are not corrected for galactic dust extinction.
GCN Circular 20581
Subject
GRB 170202A: Kanata optical and infrared observations
Date
2017-02-02T23:12:08Z (8 years ago)
From
Michitoshi Yoshida at HASC,Hiroshima U <yoshidam@hiroshima-u.ac.jp>
Mori, H., Nakaoka, T., Kawabata, M., Hirochi, J., Kawahara, N.,
Yoshida, M., Kawabata, K. and Uemura, M. (Hiroshima Univ.) on
behalf of the OISTER collaboration
We performed R-band and Ks-band imaging observations around the
error circle of GRB 170202A (Racusin et al., GCN 20575) with the
optical imager HOWPol and opt-NIR imager HONIR attached to Kanata
telescope of Hiroshima University. The observations took place at
2017-02-02 18:33:37 UT (mid time of the observation). We detected
the optical transient reported by Xin et al.(GCN 20576), Lipunov
et al. (GCN 20578) and Guidorzi et al. (GCN 20579) in our R-band
and Ks-band images. The detected magnitude of the OT and five
sigma upper limit (in Vega magnitude) of the observations are
listed below.
# T0+ MID-UT T-EXP R mag. R err R limit
-----------------------------------------------------
335 18:33:37 30 16.35 0.3 18.0
-----------------------------------------------------
# T0+ MID-UT T-EXP Ks mag. Ks err Ks limit
-----------------------------------------------------
3208 19:21:30 1320 17.1 0.4 18.6
-----------------------------------------------------
T0+ : Elapsed time after the burst [sec]
T-EXP: Total Exposure time [sec]
GCN Circular 20582
Subject
GRB 170202A: NOT afterglow observations
Date
2017-02-02T23:31:00Z (8 years ago)
From
Thomas Kruehler at MPE Garching <kruehler@mpe.mpg.de>
T. Kruehler (MPE Garching), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI),
and Pasi J. Hakala (FINCA) report on behalf of the Nordic GRB
collaboration:
We observed the field of GRB 170202A (Racusin et al. GCN 20575)
with the NOT equipped with ALFOSC. Photometry in the r and i-band
filter started at 22:46 UTC on 2017-02-02, 4.3 hr after the GRB
trigger.
Calibrating our images against magnitudes of field stars from the
SDSS catalog, we measure a preliminary brightness of the optical
afterglow (Racusin et al. GCN 20575, Xin et al. GCN 20576,
Lipunov et al. GCN 20578, Guidorzi et al. GCN 20579, Klotz et al.
GCN 20580, Mori et al. GCN 20581) of
r = 20.1 +- 0.1 mag.
This magnitude is not corrected for the expected foreground
extinction corresponding to a reddening of E_B-V = 0.02 mag
(Schlafly & Finkbeiner 2011).
GCN Circular 20584
Subject
GRB 170202A: Redshift from OSIRIS/GTC
Date
2017-02-03T00:22:15Z (8 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), L. Izzo (IAA-CSIC),
C. Thoene (IAA-CSIC), D.A. Kann (IAA-CSIC, TLS), P. Pessev
(GRANTECAN, IAC, ULL), A. Perez (GRANTECAN) report on
behalf of a larger collaboration:
We observed the afterglow of GRB 170202A (Racusin et al.
GCN 20575) using OSIRIS at the 10.4m GTC telescope at the
Roque de los Muchachos observatory (La Palma, Spain). The
observation started at 23:22 UT (4.91 hr after the burst) and
included observations with grisms R1000B and R1000R covering
the ranges 3700 - 7800 AA and 5100 - 9300 AA respectively.
The blue spectra shows a strong signal with multiple features being
especially significant Lyman-alpha (both in absorption and emission),
the full Ly-forest, NV, SII, SiII, SiII*, OI, CII, SiIV, CIV and AlII at a
common redshift of 3.645, which we identify as the redshift of the
GRB.
GCN Circular 20585
Subject
GRB 170202A: MITSuME Akeno Optical Observation
Date
2017-02-03T00:47:37Z (8 years ago)
From
Yutaro Tachibana at Tokyo Tech <tachibana@hp.phys.titech.ac.jp>
Y. Saito, R. Itoh, Y. Tachibana, K. Morita, Y. T. Yoshii, H. Ohuchi, Y. Yano, Y. Ono, T. Fujiwara, S. Harita, Y. Muraki, K. Saisho, Y. Ozawa, Y. Yatsu, and N. Kawai
(Tokyo Tech)
report on behalf of the MITSuME collaboration:
We searched for the optical counterpart of GRB 1710202A (J. L. Racusin et
al., GCN Circular #20575) 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 2017-02-02 18:28:41 UT (39 sec after the burst).
We detected the optical counterpart (J. L. Racusin et al., GCN Circular #20575
) in g', Rc and Ic band.
The measured magnitudes were listed as follows.
T0+[sec] MID-UT T-EXP[sec] g' Rc Ic
-------------------------------------------------------------------------------------------------------
54 18:28:56 30 >18.4 >17.7 >17.0
92 18:29:34 30 >19.1 17.01 +/- 0.12 17.08 +/- 0.25
131 18:30:13 30 17.61 +/- 0.13 16.38 +/- 0.09 15.89 +/- 0.12
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
GCN Circular 20586
Subject
GRB 170202A: Enhanced Swift-XRT position
Date
2017-02-03T04:26:17Z (8 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.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 2000 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 170202A, 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 = 152.51441, +5.01136 which is equivalent
to:
RA (J2000): 10h 10m 3.46s
Dec (J2000): +05d 00' 40.9"
with an uncertainty of 1.4 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 20587
Subject
GRB 170202A: Swift/UVOT Detection
Date
2017-02-03T05:18:40Z (8 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and J. L. Racusin (NASA/GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170202A
84 s after the BAT trigger (Racusin et al., GCN Circ. 20575). A source
consistent with the enhanced XRT position (Osborne et al., GCN 20586)
and is detected in the initial UVOT exposures. No detection in the U and
UV filters is consistent with the reported redshift (de Ugarte Postigo et
al,
GCN Circ. 20584).
The preliminary UVOT position is:
RA (J2000) = 10:10:03.49 = 152.51454 (deg.)
Dec (J2000) = +05:00:41.8 = 5.01161 (deg.)
with an estimated uncertainty of 0.44 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
white 84 233 147 18.31 +/- 0.05
v 625 1419 97 18.27 +/- 0.20
b 551 1345 78 19.18 +/- 0.19
u 295 1837 363 >21.1
w1 675 1812 136 >19.6
w2 1030 1050 19 >19.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 20588
Subject
GRB 170202A: Xinglong 2.16m photometry and spectroscopic redshift
Date
2017-02-03T07:31:00Z (8 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
D. Xu (NAOC), Y. Qin (Geneva Observatory), Y.D. Hu (IAA-CSIC), H.J.
Wang, H. Wu, M. He, H.X. Feng, Z.P. Zhu (NAOC) report:
We observed the optical afterglow of GRB 170202A (Racusin et al., GCN
20575) using the 2.16-m telescope at Xinglong, Hebei, China, equipped
with the BFOSC camera. The observation started at 18:59:32 UT on
2017-02-02 (i.e., 31.5 mins after the BAT trigger), 4x120s R-band
photometry was obtained, followed by 1x3600s spectroscopy using the
G4+385LP grism setting, covering the wavelength of ~3600 - 8500 AA.
The optical afterglow has m(R)~18.0 mag from the first R-band exposure,
calibrated with the nearby SDSS stars.
Preliminary analysis shows that the spectrum is featured by a prominent
Lyman_alpha trough, a Lyman forest blue to the trough, together with Si
IV, C IV and other potential absorption lines red to the trough, all at
a common redshift of z = 3.65. This redshift value is consistent with
measurement in de Ugarte Postigo et al. (GCN 20584).
GCN Circular 20590
Subject
GRB 170202A VLT/X-shooter redshift [minor correction]
Date
2017-02-03T09:55:04Z (8 years ago)
From
Jesse Palmerio at IAP <palmerio@iap.fr>
J. Palmerio (Univ. Paris VI, IAP), T. Kruehler (MPE Garching),
D. Xu (NAOC,CAS), D. Malesani, J. P. U. Fynbo (DARK/NBI)
report on behalf of a larger collaboration:
We observed the optical afterglow of GRB 170202A
(Racusin et al. GCN 20575) with the ESO
Very Large Telescope UT 2 (Kueyen) equipped with the X-shooter
spectrograph, covering the wavelength range 3500-25000 AA.
Spectroscopy started at 04:10:05 UT on 2017-02-03 (i.e., 9.7 hr after the
GRB)
and consisted of 4 exposures of 600 s each.
The spectrum exhibits several absorption features such as Lya, CIV,
SiIV, FeII, SiII, MgII as well as the [OIII]5007 emission line,
all at a common redshift of z=3.645, consistent with
A. de Ugarte Postigo et al. (GCN 20584) and D. Xu et al. (GCN 20588).
We conclude this is the redshift of the GRB.
We acknowledge the excellent support from the ESO staff, particularly
Fernando J. Selman, A. Mehner in obtaining these observations.
GCN Circular 20591
Subject
GRB 170202A: T100 observations
Date
2017-02-03T10:29:03Z (8 years ago)
From
Eda Sonbas at NASA/GSFC <edasonbas@gmail.com>
E. Sonbas (Adiyaman Univ.), T. Guver, M. De Pasquale (Istanbul Univ.), E.
Gogus (Sabanci Univ.), O. Erece, M. Kocak, H. Kirbiyik, H. Esenoglu (TUG)
report on behalf of a larger collaboration
We observed the field of Swift GRB 170202A (Racusin et al., GCN#20575) with
the 1.0 meter T100 telescope (Bakirlitepe, TUBITAK National Observatory,
Turkey), starting February, 2, 20:12:45.56 UT (~ 1.7 hours after the
trigger). Observations were carried out in the R filter. The afterglow is
detected in the R band images with an exposure time of 300 s.
Using USNO-B1 stars USNO-B1 0950-0184329 (R.A.=152.492, Dec=+5.028) and
USNO-B1 0949-0181744 (R.A.=152.514, Dec=+4.993) in the field, the magnitude
of the OT was estimated as follows;
t-t0 (hr) exp.(s) filt mag err (+/-)
1.75 300 R 18.98 0.07
Analysis of further observations with the same filter is ongoing.
We thank to TUBITAK National Observatory for a partial support in using
T100 telescope with project number 10CT100-95 and technical support.
GCN Circular 20592
Subject
GRB 170202A: Swift-XRT refined Analysis
Date
2017-02-03T11:12:09Z (8 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N. Burrows (PSU), A.
Cholden-Brown (PSU), S. J. LaPorte (PSU), A.P. Beardmore (U.
Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A.
D'Ai (INAF-IASFPA) and J.L. Racusin report on behalf of the Swift-XRT
team:
We have analysed 6.7 ks of XRT data for GRB 170202A (Racusin et al. GCN
Circ. 20575), from 64 s to 40.8 ks after the BAT trigger. The data
comprise 131 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. 20586).
The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=2.9 (+3.3, -0.6). At T+84.5 s the decay
flattens to an alpha of -1.5 (+0.0, -2.0). The light curve breaks again
at T+95.5 s to a decay with alpha=3.15 (+0.19, -0.17), and again at
T+314 s s to alpha=0.01 (+0.17, -0.18), before a final break at T+2223
s s after which the decay index is 1.08 (+0.12, -0.17).
A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.94 (+0.09, -0.08). The
best-fitting absorption column is 3.7 (+6.4, -3.7) x 10^21 cm^-2, at a
redshift of 3.645, in addition to the Galactic value of 2.0 x 10^20
cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index
of 2.00 (+0.13, -0.12) and a best-fitting absorption column of 5.2
(+8.8, -5.2) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10
keV flux conversion factor deduced from this spectrum is 3.2 x 10^-11
(3.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Galactic foreground: 2.0 x 10^20 cm^-2
Intrinsic column: 5.2 (+8.8, -5.2) x 10^21 cm^-2 at z=3.645
Photon index: 2.00 (+0.13, -0.12)
If the light curve continues to decay with a power-law decay index of
1.08, the count rate at T+24 hours will be 0.018 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.9 x
10^-13 (6.4 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/00736407.
This circular is an official product of the Swift-XRT team.
GCN Circular 20593
Subject
GRB 170202A: LCO FTN observations
Date
2017-02-03T11:36:23Z (8 years ago)
From
Cristiano Guidorzi at Ferrara U,Italy <guidorzi@fe.infn.it>
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc
(U. Nova Gorica), C.G. Mundell (U. Bath) on behalf of a large
collaboration report:
We observed Swift GRB 170202A (Racusin et al. GCN 20575) on February 03,
from 10:30 to 10:40 UT (16 hours since the GRB) with the 2-m LCO FTN in
Hawaii with SDSS r and i filters. We detect the optical afterglow with
the following values:
Mid Time Exposure Filter Magnitude (AB)
(hours) (s)
-------------------------------------------------------
16.1 2x120 SDSS-R 21.10 +- 0.15
16.2 2x120 SDSS-I 20.94 +- 0.19
-------------------------------------------------------
as calibrated against nearby SDSS sources.
GCN Circular 20594
Subject
GRB 170202A: SQUEAN Observation
Date
2017-02-03T13:25:13Z (8 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
Myungshin Im, Yongjung Kim, & Joonho Kim (CEOU/SNU)
We observed the field of GRB 170202A (Racusin et al., GCN 20575) using
the SQUEAN instrument on the 2.1m Otto Struve telescope at the McDonald
Observatory, Texas. The observation started at 2017-02-03 10:26:26 UT,
��� ���
or about 16 hours after the BAT alert.
We identify the afterglow at the location of the reported GRB position,
with the following preliminary results based on the photometry calibration
using SDSS stars in the vicinity.
Filter Mag (AB) Mag_err Exp.time Start-time (UT)
��� r 21.1 0.08 180s x 3 10:26:26.6���
i 20.6 0.06 180s x 3 10:36:20.7
z 20.5 0.10 180s x 3 10:47:15.6
Further observations are planned.
GCN Circular 20595
Subject
GRB 170202A: RATIR Optical and NIR Observations
Date
2017-02-03T16:56:06Z (8 years ago)
From
Nat Butler at UC berkeley <natxbutler@gmail.com>
Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier
Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora
Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy
(UMD) report:
We observed the field of GRB 170202A (Racusin, et al., GCN 20575) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2017/02 3.18 to 2017/02 3.57 UTC (9.92 to
19.17 hours after the BAT trigger), obtaining a total of 3.98 hours
exposure in the r and i bands and 1.68 hours exposure in the Z and Y bands.
For a source within the Swift-XRT error circle (Osborne, et al., GCN
20586), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the
following detections:
r = 20.68 +/- 0.01
i = 20.83 +/- 0.02
Z = 20.84 +/- 0.07
Y = 20.50 +/- 0.06
These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.
We thank the staff of the Observatorio Astron��mico Nacional in San Pedro
M��rtir.
GCN Circular 20596
Subject
GRB 170202A: Swift-BAT refined analysis
Date
2017-02-03T17:28:41Z (8 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), 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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170202A (trigger #736407) (Racusin, et al.,
GCN Circ. 20575). The BAT ground-calculated position is RA, Dec = 152.526, 5.021 deg
which is RA(J2000) = 10h 10m 06.3s Dec(J2000) = +05d 01' 15.7" with an uncertainty
of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 50%.
The mask-weighted light curve shows a multi-peaked structure. The first peak
starts at T+0 sec, peaks at T+3 sec and decays to near background by T+15 sec,
at which time the second, larger peak begins. This structure peaks at T+17 sec,
and the third overlapping peak has a maximum at T+21 sec, and decays to
near background by T+50 sec, with some low-level emission extending out to
T+80 sec. T90 (15-350 keV) is 46.2 +- 11.5 sec (estimated error including systematics).
The time-averaged spectrum from T+0.25 to T+76.46 sec is best fit by
a simple power-law model. The power law index of the time-averaged
spectrum is 1.68 +- 0.07. The fluence in the 15-150 keV band is
3.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from
T+16.04 sec in the 15-150 keV band is 4.7 +- 0.3 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/736407/BA/
GCN Circular 20598
Subject
GRB 170202A: Etelman Observatory optical observations
Date
2017-02-03T22:24:51Z (8 years ago)
From
Bruce Gendre at ASDC <bruce.gendre@gmail.com>
B. Gendre (UVI), N. Orange (OrangeWave Innovative Science, LLC), D.
Morris (UVI), A. Cucchiara (UVI), D. Drost (UVI), T. Giblin (USAF
Academy), J. Hakkila (College of Charleston), A. Klotz (IRAP), J. Neff
(NSF), D. Smith (UVI), J. Staff (UVI), P. Thierry (Auragne Observatory),
R. Watlington (UVI), and L. Wentlent (UVI) report:
We observed the field of GRB 170202A (Racusin et al. GCN 20575) with the
0.5m Virgin Island Robotic Telescope (VIRT) on February the 3rd,
starting at 3:16 UT (8.8 hours after the trigger), until 10:30 UT. We
performed a series of exposures in the clear filter. The weather
conditions were variable with a typical estimated seeing of 2".
We detected the afterglow observed by UVOT (Racusin et al., GCN 20575)
on a combined image (spanning times from 10h to 11.92h after the
trigger). Its magnitude, estimated by comparison to nearby USNO-B1
stars, was R = 20.8 +/- 0.3.
Further analysis is in progress.
Magnitudes have not been corrected for Galactic extinction. The VIRT is
still in its commissioning phase.
This message can be cited.
GCN Circular 20599
Subject
GRB 170202A: Zadko observatory - Gingin optical observations
Date
2017-02-03T22:58:08Z (8 years ago)
From
Alain Klotz at IRAP-CNRS-OMP <Alain.Klotz@free.fr>
A. Klotz, D. Turpin (IRAP-CNRS-OMP),
D. Macpherson (UWA/ICRAR), D. Coward (UWA),
M. Boer, R. Laugier (UNS-CNRS-OCA),
Gendre B. (UVI - Etelman Obs.),
A. Williams (PO-UWA), R. Martin (PO-UWA)
report:
We continue to image the field of GRB 170202A
with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia
(see Klotz et al. GCNC 20580 for early measures).
The observations started 19.56h after the GRB trigger
and were stopped at t0+22.99h. We stacked 25 images
of 180s with no filter.
We detect the optical transcient described by Racusin et
al. (GCNC 20575), Xin et al. (GCNC 20576) and Lipunov et
al. (GCNC 20578). We calibrated magnitudes using the same
reference star than Xin et al. (GCNC 20576):
t0+19.56h t0+22.99h R=21.8 +/-0.4
Magnitudes are not corrected for galactic dust extinction.
GCN Circular 20601
Subject
GRB 170202A: SQUEAN Observation (2nd night)
Date
2017-02-04T11:15:37Z (8 years ago)
From
Myungshin Im at Seoul Nat U <mim@astro.snu.ac.kr>
Myungshin Im, Yongjung Kim, & Joonho Kim (CEOU/SNU)
We continued the observation of the GRB 170202A afterglow with the SQUEAN
instrument on the 2.1m Otto Struve telescope at the McDonald Observatory,
Texas. The 2nd night observation started at 2017-02-04 09:45:52 UT,
��� ���or
about 39.3 hours after the BAT alert.
The afterglow shows the following preliminary magnitude based on the
photometry calibration using SDSS stars in the vicinity.
Filter Mag (AB) Mag_err Exp.time Start-time (UT)
r 21.8 0.15 180s x 10 09:45:52���
GCN Circular 20604
Subject
Konus-Wind observation of GRB 170202A
Date
2017-02-05T14:32:27Z (8 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov,
D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 170202A (Swift-BAT trigger #736407: Racusin et al.,
GCN 20575; Barthelmy et al., GCN 20596; T0(BAT)=18:28:02.373 UT)
was detected by Konus-Wind (KW) in the waiting mode.
The light curve shows a double-peaked with a duration of ~30 s.
Modeling the KW 3-channel time-integrated spectrum
(from T0(BAT)+0.907 s to T0(BAT)+30.347 s) by
a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.16(-0.34,+0.59) and Ep = 247(-86,+166) keV.
The energy fluence (20 keV-10 MeV) for this time interval
is (5.9 �� 1.4)x10^-6 erg/cm2.
Assuming the redshift z=3.645 (de Ugarte Postigo et al., GCN 20584)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the burst isotropic energy release E_iso to ~1.7x10^53 erg
and the rest-frame peak energy of the time-integrated spectrum,
Ep,z, to ~1150 keV.
The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB170202A/
All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.
GCN Circular 20606
Subject
GRB 170202A: SMARTS optical/IR afterglow observations
Date
2017-02-05T16:55:09Z (8 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 170202A
(GCN 20575, Racusin et al.) at three different epochs: 0.41671
[2017-02-03 04:28 UT], 0.53096 [2017-02-03 07:13 UT] and 2.39175
[2017-02-05 03:52 UT] days post-burst. At each epoch, total summed
exposure times amounted to 36 minutes in I and 30 minutes in J.
The afterglow of GRB 170202A (e.g. GCN 20575, Racusin et al.;
GCN 20576, Xin et al.; GCN 20578, Lipunov et al.) is detected
in our early images, with the preliminary magnitudes (and 3-sigma
limits) listed below. Note that the optical photometry is calibrated
against USNO-B1.0 stars in the field, so suffers from a large
photometric calibration error of about +/-0.3 magnitudes, which has
not been included in the errors quoted below. The IR photometry
is calibrated against the single 2MASS star in our field-of-view,
so similarly may include a large (but unknown) calibration error.
mid-exposure time
(days post-burst) I mag J mag
0.41671 20.1+/-0.1 18.9+/-0.1
0.53096 20.6+/-0.1 >18.5
2.39175 >21.0 >18.6
GCN Circular 20666
Subject
GRB 170202A: 15 GHz upper limits from AMI
Date
2017-02-12T19:20:00Z (8 years ago)
From
Kunal Mooley at Oxford U <kunal.mooley@physics.ox.ac.uk>
K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender
(Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D.
Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods,
P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)
The AMI Large Array robotically triggered on the Swift alert for GRB
170202A (Racusin et al., GCN 20575) as part of the 4pisky program, and
subsequent follow up observations were obtained up to 10 days
post-burst. Our observations at 15 GHz on 2016 Feb 02.87, Feb 04.00, Feb
06.04, Feb 07.01 and Feb 09.00 (UT) do not reveal any radio source at
the XRT location (Osborne et al., GCN 20586), with 3sigma upper limits
of 451 uJy, 69 uJy, 81 uJy, 352 uJy and 105 uJy respectively.
We thank the AMI staff for scheduling these observations. The AMI-GRB
database is a log of all GRB follow up observations with the AMI, and is
available at http://4pisky.org/ami-grb/.