GRB 181213A
GCN Circular 23525
Subject
GRB 181213A: Swift detection of a burst
Date
2018-12-13T13:08:00Z (6 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
P. A. Evans (U Leicester), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),
K. L. Page (U Leicester) and A. Tohuvavohu (PSU) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 12:57:38 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 181213A (trigger=876016). Swift will slew at ~T+33 min
due to an observing constraint. The BAT on-board calculated location is
RA, Dec 248.207, +78.504, which is
RA(J2000) = 16h 32m 50s
Dec(J2000) = +78d 30' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows multiple peaks
with a total duration of about 25 sec. The peak count rate
was ~850 counts/sec (15-350 keV), at ~1 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+33.8
minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is P. A. Evans (pae9 AT star.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 23526
Subject
SWIFT GRB181213A Global MASTER-Net bright OT discovery
Date
2018-12-13T14:00:20Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina,
P.Balanutsa,
A.Kuznetsov, V.V.Chazov, D. Vlasenko
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University
A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory
K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk
Irkutsk State University
V. Yurkov, A. Gabovich, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk
R. Podesta, Carlos Lopez and F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)
Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)
R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias
D. Buckley, S. Potter, A. Kniazev, M. Kotze
South African Astronomical Observatory
MASTER-Amur robotic telescope (Global MASTER-Net:
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,
vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical
University) was pointed to the SWIFT GRB181213.54 (Evens et al. GCN
23525) 81 sec after trigger time at 2018-12-13 12:58:59 UT,
with upper limit up to 17.3 mag. The observations began at zenit distance
= 51 deg. The sun altitude is -50.9 deg.
We find bright OT at a position
16h 33m 04.88s , +78d 29m 48.15s
with magnitude is about 14.9
The galactic latitude b = -60 deg., longitude l = 98 deg.
GCN Circular 23527
Subject
GRB 181213A: BOOTES-5/JGT optical observations
Date
2018-12-13T14:02:26Z (6 years ago)
From
Youdong HU at IAA-CSIC, UGR <youdong@iaa.es>
Y.-D. Hu, I. Carrasco, E. Fernandez-Garcia and A. J. Castro-Tirado
(IAA-CSIC),
D. Hiriart and W. H. Lee (UNAM), S. Jeong and I. H. Park (SKKU) and M.
D.
Caballero-Garcia (ASU-CAS, CZ) on behalf of a larger collaboration,
report:
The 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico
Nacional in San Pedro Martir (Mexico) automatically responded in 95 s
to the Swift trigger of GRB 181213A Evans et al., GCNC 23525).
The first image (10s exposure, g-band) was obtained at 12:59:13.72 UT.
Within the Swift/BAT error box, we identify an optical source at
coordinates
RA = 16 33 04.75 Dec = +78 29 48.3 (J2000) of about 15.6 mag, which is
fading
in brightness in the late time images. Therefore we propose this source
to be
the optical afterglow to GRB 181213A. Spectroscopic bbservations are
encouraged.
We thank the staff at Observatorio Astronomico Nacional in San Pedro
Martir for its excellent support.
GCN Circular 23528
Subject
GRB 181213A: Swift-XRT observations
Date
2018-12-13T14:07:01Z (6 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.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 181213A at 13:36:41.2 UT,
2342.8 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 248.27284,
78.49726 which is equivalent to:
RA(J2000) = 16h 33m 05.48s
Dec(J2000) = +78d 29' 50.1"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 53 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 4.49
x 10^20 cm^-2 (Willingale et al. 2013).
GCN Circular 23529
Subject
GRB181213A: Swift/UVOT Detection
Date
2018-12-13T14:28:38Z (6 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and P. A. Evans (U Leicester) report on behalf of the Swift UVOT team:
UVOT took a finding chart exposure of 150 seconds with the White filter
starting 2352 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 16:33:04.87 = 248.27028
DEC(J2000) = +78:29:48.8 = 78.49690
with a 90%-confidence error radius of about 0.75 arc sec. This position is 2.2
arc sec. from the center of the XRT error circle and consistent with the optical
afterglow reported by MASTER (Lipunov et al., GCN Circ. 23526) and BOOTES
(Hu et al., GCN Circ. 23527). The estimated magnitude is
17.26 with a 1-sigma error of about 0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.04.
[GCN OPS NOTE(13dec18): The "A" was added tot he GRB designation in the SUBUJECT-line.]
GCN Circular 23530
Subject
GRB 181213A : TSHAO optical observations
Date
2018-12-13T17:45:03Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Kusakin (FAPHI), A. Pozanenko (IKI), I. Reva
(FAPHI), A. Volnova (IKI), E. Mazaeva (IKI), M. Krugov (FAPHI) report
on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne
et al., GCN 23528) with Zeiss-1000 1-m telescope of Tien Shan
Astronomical Observatory starting on Dec. 13 (UT) 13:39:23. We detected
the OT reported earlier (Lipunov et al., GCN 23526; Hu et al. GCN 23527;
Siegel et al., GCN 23529). Preliminary photometry of the object is
following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2018-12-13 13:39:23 0.04427 R 2640 17.27 0.08 21.8
The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1684-0061916 15.83
1684-0061968 16.55
GCN Circular 23532
Subject
GRB 181213A: GWAC-F60A upper limit
Date
2018-12-14T01:48:15Z (6 years ago)
From
L.P. Xin at NAOC <xlp@nao.cas.cn>
X. H. Han, R. S. Zhang, L. P. Xin, J. Wang, P. P. Zhang, J. Y. Wei, E. W. Liang,
X. G. Wang, Y. J. Xiao, Y. G. Yang, X. M. Lu, L. Huang, H. B. Cai,
X. M. Meng, Y. L. Qiu, Y. Xu, Y. J. Xiao, Y. T. Zheng, C. Wu,
J. S. Deng, D. W. Xu, D. TURPIN, H. L. Li, and W. L. Dong, report:
We observed GRB 181213A ( Evans et al., GCN 23525; Osborne
et al., GCN 23528 ) with GWAC-F60A 60cm optical telescope
at 21:21:34 UT, Dec. 13th 2018, about 8.4 hours after the burst.
The exposure time is 150 sec in R band. the airmass is 1.56.
The optical afterglow reported by (Lipunov et al., GCN 23526; Hu et al. GCN 23527;
Siegel et al., GCN 23529; Belkin et al., GCN 23530) is not detected with an upper
limit of 18.2 mag in R band image. The brightness is calibrated by nearby USNO-B1.0 stars.
GWAC-F60A is operated by Guangxi university and NAOC, CAS,
at Xinglong observatory, China.
The message may be cited.
GCN Circular 23533
Subject
GRB 181213A: Swift-BAT refined analysis
Date
2018-12-14T05:04:44Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), H. A. Krimm (NSF/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 181213A (trigger #876016)
(Evans et al., GCN Circ. 23525). The BAT ground-calculated position is
RA, Dec = 248.210, 78.500 deg which is
RA(J2000) = 16h 32m 50.5s
Dec(J2000) = +78d 30' 00.7"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 21%.
The mask-weighted light curve shows a multi-peaked structure that starts
at ~T-1 s and ends at ~T+16 s. Note that the burst went out of the BAT
field of view at ~T+100 s. T90 (15-350 keV) is 15.31 +- 1.24 sec (estimated
error including systematics).
The time-averaged spectrum from T-0.70 to T+15.94 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.57 +- 0.20. The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+1.16 sec in the 15-150 keV band
is 2.1 +- 0.6 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/876016/BA/
GCN Circular 23535
Subject
GRB 181213A: Enhanced Swift-XRT position
Date
2018-12-14T09:44:59Z (6 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 760 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 181213A, 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 = 248.27007, +78.49697 which is equivalent
to:
RA (J2000): 16h 33m 4.82s
Dec (J2000): +78d 29' 49.1"
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 23536
Subject
GRB 181213A: Swift-XRT refined Analysis
Date
2018-12-14T10:00:33Z (6 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.
Tohuvavohu (PSU), S. J. LaPorte (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai
(INAF-IASFPA) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 181213A (Evans et al. GCN
Circ. 23525), from 2.4 ks to 37.9 ks after the BAT trigger. The data
comprise 218 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Osborne et al. (GCN Circ. 23535).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.44 (+0.10, -0.09).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.06 (+0.22, -0.20). The
best-fitting absorption column is 7.2 (+5.4, -2.8) x 10^20 cm^-2,
consistent with the Galactic value of 4.5 x 10^20 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum is 3.2 x 10^-11 (3.8 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 7.2 (+5.4, -2.8) x 10^20 cm^-2
Galactic foreground: 4.5 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 2.06 (+0.22, -0.20)
If the light curve continues to decay with a power-law decay index of
1.44, the count rate at T+24 hours will be 2.2 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.9 x
10^-14 (8.3 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00876016.
This circular is an official product of the Swift-XRT team.
GCN Circular 23537
Subject
GRB 181213A: NOT optical observations
Date
2018-12-14T10:01:41Z (6 years ago)
From
Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI <keh14@hi.is>
K. E. Heintz (Univ. of Iceland), D. B. Malesani (DAWN/NBI/DTU and DARK/NBI), J. P. U. Fynbo (DAWN/NBI/DTU), A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), L. Balaguer-Nu��ez, J. Carbajo (Dept. FQA, Univ. de Barcelona), F. Galindo and C. Perez (NOT), report on behalf of a larger collaboration:
We observed the optical afterglow (Lipunov et al., GCN 23526; Hu et al., GCN 23527; Siegel et al., GCN 23529; Belkin et al., GCN 23530) of GRB 181213A (Evans et al., GCN 23525) with the 2.5-m Nordic Optical Telescope (NOT) equipped with AlFOSC.
Spectroscopy was secured: we obtained 4x900s exposures using grism 4 (with a wavelength coverage from 350 to 900 nm) starting at 23:27:14 UT on December 13 (i.e. 10.5 hr after trigger). The observations were obtained at a seeing around 1��� but at an airmass > 3. From the acquisition image taken without filter we measure r = 20.6 +/- 0.2 AB mag, calibrated against SDSS r-band Pan-STARRS local photometry. The combined spectrum shows a low-S/N, mostly featureless continuum. Based on the detected continuum down to 415 nm we infer an upper limit on the redshift for the GRB of z < 2.4.
GCN Circular 23538
Subject
GRB 181213A: HMM-0.5m, NEXT-0.6m, CNEOST-1m optical observations
Date
2018-12-14T11:07:54Z (6 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu, D. Xu (NAOC), X. Zhang, J.H. Liu (XAO), B. Li, H.B. Zhao
(PMO), X. Gao (Urumqi No.1 Senior High School), M. Yang (XJTS) report:
We observed the field of GRB 181213A (Evans et al., GCN 23525; Lipunov
et al., GCN 23526; Hu et al., GCN 23527) using the HMT-0.5m telescope
located at Gao-Ya-Zi, Xinjiang, China at 14:32:10 on 2018-12-13, i.e.,
1.57hr after the Swift trigger, and obtained 45x90s, 1x120s, 1x180s
unfiltered frames.
The afterglow is clearly detected in part of the HMT images, and
preliminary results are as follows:
Date Tstart (UT) T-T0(hr) Exp.(s) Mag(R)
2018-12-13 14:55:00 1.95 3x90 18.0+/-0.1
2018-12-13 15:00:25 2.03 5x90 18.1+/-0.1
We also used the NEXT-0.6m telescope located at Nanshan, Xinjiang, at
14:49:04 UT on 2018-12-13, i.e., 1.85hr after the Swift trigger and
obtained 5x90s R-band frames under cloudy weather. The afterglow is not
detected down to a limiting magnitude of R~17 mag, calibrated with the
SDSS field.
Additionally, the CNEOST-1m telescope started observation at 21:43:36 on
2018-12-13, i.e., 8.76hr after the Swift trigger and we obtained 15x90s
VR-band frames. The afterglow is not detected down to a 3-sigma upper
limit of ~20.3 mag.
GCN Circular 23539
Subject
GRB 181213A: AbAO optical observations
Date
2018-12-14T11:31:27Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO),
V.R. Ayvazian (AbAO), G. V. Kapanadze (AbAO), E. Mazaeva (IKI),
A. Volnova (IKI), I. Molotov (KIAM) report on behalf of larger GRB
follow-up collaboration:
We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne
et al., GCN 23528) with AS-32 (0.7m) telescope of Abastumani Observatory
starting on Dec. 13 (UT) 15:42:55. We detected the OT (e.g. Lipunov
et al., GCN 23526; Hu et al. GCN 23527; Siegel et al., GCN 23529;
Belkin et al., GCN 23530). Preliminary photometry of the afterglow is
following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2018-12-13 15:42:55 0.13264 R 65*60 18.75 0.08 20.9
The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1684-0061916 15.83
1684-0061968 16.55
GCN Circular 23542
Subject
GRB 181213A:Insight-HXMT/HE detection
Date
2018-12-15T11:37:34Z (6 years ago)
From
Shuo Xiao at IHEP <xiaoshuo@ihep.ac.cn>
S. Xiao, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, J. L. Zhao,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
At 2018-12-13T12:57:38.000 (T0), the Insight-HXMT/HE detected
GRB 181213A (trigger ID: HEB181213540) in a routine search of the data,
which was also triggered by Swift/BAT (Evans et al., GCN23525).
The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 15.67 s measured from T0+0.74 s.
The 1-s peak rate, measured from T0+1.81 s, is 738.8 cnts/s.
The total counts from this burst is 6164.7 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB181213540_lc.jpg
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.
Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information could be found at: http://www.hxmt.org.
GCN Circular 23543
Subject
GRB 181213A: continued TSHAO optical observations
Date
2018-12-16T11:01:22Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Kusakin (FAPHI), A. Pozanenko (IKI), I. Reva
(FAPHI), E. Mazaeva (IKI), A. Volnova (IKI), M. Krugov (FAPHI) report
on behalf of larger GRB follow-up collaboration:
We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne
et al., GCN 23528) with Zeiss-1000 1-m telescope of Tien Shan
Astronomical Observatory starting on Dec. 14 (UT) 13:29:58. We detected
the afterglow (Lipunov et al., GCN 23526; Hu et al. GCN 23527; Siegel
et al., GCN 23529; Belkin et al., GCN 23530; Heintz et al., GCN 23537).
Preliminary photometry of the object is following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2018-12-14 13:29:58 1.06482 R 7200 21.65 0.28 21.9
The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1684-0061916 15.83
1684-0061968 16.55
GCN Circular 23544
Subject
GRB 181213A: Mondy optical observations
Date
2018-12-16T22:42:44Z (6 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), E. Mazaeva (IKI), A.
Volnova (IKI) report on behalf of IKI-FuN:
We observed the field of GRB 181213A (Evans et al., GCN 23525; Osborne et
al., GCN 23528) with AZT-33IK telescope of Sayan observatory (Mondy). We
marginally detected the afterglow (Lipunov et al., GCN 23526; Hu et al.
GCN 23527; Siegel et al., GCN 23529; Belkin et al., GCN 23530; Heintz et
al., GCN 23537) on Dec. 15 (UT start) 11:57:21
Preliminary photometry of the filed and and the aferglow is following.
Date UT start t-T0 Filter Exp. OT Err. UL
(mid, days) (s)
2018-12-14 12:10:22 0.97344 R 10*120 n/d n/d 20.9
2018-12-15 11:57:21 1.97829 R 29*120 23.15 0.45 23.1
The photometry is based on nearby USNO-B1.0 stars
USNO-B1.0_id R2
1684-0061916 15.83
1684-0061968 16.55
GCN Circular 23545
Subject
GRB 181213A: Swift/UVOT Observations
Date
2018-12-18T20:20:49Z (6 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 181213A
2352 s after the BAT trigger (Evans et al., GCN Circ. 23525). A fading
optical afterglow consistent with initial reports (Lipunov et al., GCN
Circ. 23526, Hu et al., GCN Circ. 23529) was detected in four of UVOT���s
filters. The lack of detection of this bright burst in the bluer filters
would imply a redshift of z > 1.4, which is not inconsistent with the
spectroscopic redshift of z < 2.4 from Heintz et al. (GCN Circ. 23537).
The preliminary UVOT position is:
RA (J2000) = 16:33:04.86 = 248.27025 (deg.)
Dec (J2000) = +78:29:48.7 = 78.49685 (deg.)
with an estimated uncertainty of 0.43 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 (fc) 2353 2503 294 17.33+/-0.04
white 2633 2653 19 17.15+/-0.10
white 8535 9061 513 19.03+/-0.07
white 66263 67021 738 >21.71
v 2683 2703 19 >17.35
v 26217 37929 1168 >20.45
b 2608 3393 87 17.82+/-0.10
b 8330 15947 230 19.18+/-0.23
b 65351 82801 1115 >20.39
u 2584 3318 216 17.25+/-0.06
u 14999 33141 1327 19.69+/-0.10
u 71983 72421 426 >20.32
uvw1 2559 3113 216 17.50+/-0.11
uvw1 14093 32991 2656 20.07+/-0.16
uvw1 71077 71977 885 >19.97
uvm2 2708 2908 196 >19.26
uvm2 19555 32084 2047 >20.84
uvw2 2659 2679 19 >17.50
uvw2 25310 37634 1771 >20.67
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).