GRB 190103B

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. A. Kennea (PSU),
H. A. Krimm (NSF/USRA), M. J. Moss (George Washington University),
K. L. Page (U Leicester), D. M. Palmer (LANL),
J. L. Racusin (NASA/GSFC) and A. Tohuvavohu (PSU) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 21:03:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190103B (trigger=881709).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 212.574, +35.261, which is 
   RA(J2000)  =  14h 10m 18s
   Dec(J2000) = +35d 15' 40"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows several overlapping peaks
with a duration of about 40 sec.  The peak count rate
was ~5800 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 21:05:24.5 UT, 93.3 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 212.5695, 35.2617 which is equivalent to:
   RA(J2000)  = 14h 10m 16.68s
   Dec(J2000) = +35d 15' 42.1"
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This
location is 13 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

The initial flux in the 2.5 s image was 7.42e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 102 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
0.01. 

Burst Advocate for this burst is A. Y. Lien (amy.y.lien 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.)

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2781 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 190103B, 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 = 212.56927, +35.26100 which is equivalent
to:

RA (J2000): 14h 10m 16.63s
Dec (J2000): +35d 15' 39.6"

with an uncertainty of 1.7 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.

B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne (U. Leicester), K.L. Page
(U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB),
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), A.
Tohuvavohu (PSU) and A.Y. Lien report on behalf of the Swift-XRT team:

We have analysed 7.8 ks of XRT data for GRB 190103B (Lien et al. GCN
Circ. 23602
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 ), from 99 s to 18.1 ks after the  BAT trigger. The data
comprise 437 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Evans et al. (GCN Circ. 23603
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 ).

The late-time light curve (from T0+4.2 ks) can be modelled with a
power-law decay with a decay index of alpha=1.03 (+/-0.10).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index	of 2.38 (+/-0.06). The
best-fitting absorption column is  4.27 (+0.28, -0.27) x 10^21 cm^-2,
in excess of the Galactic value of 1.4 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.89 (+/-0.11) and a
best-fitting absorption column of 3.9 (+0.6, -0.5) x 10^21 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.1 x 10^-11 (6.0 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     3.9 (+0.6, -0.5) x 10^21 cm^-2
Galactic foreground: 1.4 x 10^20 cm^-2
Excess significance: 11.8 sigma
Photon index:	     1.89 (+/-0.11)

If the light curve continues to decay with a power-law decay index of
1.03, the count rate at T+24 hours will be 0.027 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (1.6 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00881709.

This circular is an official product of the Swift-XRT team.

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), 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 downlink,
we report further analysis of BAT GRB 190103B (trigger #881709)
(Lien, et al., GCN Circ. 23602
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 ).  The BAT ground-calculated position is
RA, Dec = 212.561, 35.254 deg which is
  RA(J2000)  =  14h 10m 14.6s
  Dec(J2000) = +35d 15' 13.4"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 6%.

The mask-weighted light curve shows several overlapping pulses that starts at
~T-10 s and ends at ~T+16 s. The main peak occurs at ~T0. T90 (15-350 keV)
is 19.5 +- 2.7 sec (estimated error including systematics).

The time-averaged spectrum from T-10.43 to T+16.18 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.99 +- 0.29,
and Epeak of 85.0 +- 18.6 keV (chi squared 58.41 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T+0.60 sec in the 15-150 keV band is
16.3 +- 1.5 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.63 +- 0.06 (chi squared 74.91 for 57 d.o.f.).  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/881709/BA/

U.Quadri, L.Strabla and A.Quadri report:

We imaged the field of GRB 190103B detected by SWIFT(trigger 881709)
with the robotic telescope of (IAU station 565) Bassano Bresciano 
Observatory, Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
ISSP - Italian Supernovae Search Project.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.

The observations started 194.16 min after the GRB trigger,�� 
with our Schmidt telescope D=320/400 mm F/D=3.1.

Weather conditions were good.

We co-added 64 exposures of 240 sec each.

Start T0+���������� End T0+����������  Vlim
194.16 min���� 459.27 min��������19.5

We did not found any optical counterpart in the error box of the XRTcandidate.
A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. A. Kennea (PSU), et al.

Magnitudes were estimated with the UCAC4 cat. and 
are not corrected for galactic dust extinction.

Reference:
http://www.osservatoriobassano.org/GRB.asp

The message may be cited.

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The�� GRB 190103B (Swift detection: Lien et al., GCN 23602
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 ;
Markwardt�� et al., GCN 23606
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 )
triggered Konus-Wind at T0=75832.010 s UT (21:03:52.010).

The burst light curve shows a double-peaked structure
which starts at ~T0-10 s and has a total duration of ~27 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.96(-0.08,+0.08)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+1.408 s,
of 3.87(-0.79,+0.79)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+22.528 s)
is best fit in the 20 keV - 16 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with�� alpha = -1.17(-0.09,+0.09),
and Ep = 142(-9,+11) keV (chi2 = 97/98 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.88 (chi2 = 97/97 dof).

The spectrum near the peak count rate
(measured from T0+0.256 to T0+6.144 s)
is best fit in the 20 keV - 16 MeV range
by the power law with exponential cutoff model
with�� alpha = -0.96(-0.10,+0.10),
and Ep = 157(-10,+11) keV (chi2 = 90/92 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.92 (chi2 = 90/91 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190103_T75832/

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.

A. Tezuka, A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone 
(AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 190103B (Swift-BAT trigger #881709: Lien et al.,
GCN Circ. 23602
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 , Markwardt et al., GCN Circ. 23606
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 ;
Konus-Wind observation: Tsvetkova et al., GCN Circ. 23612
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 )
triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 21:03:46.478 UTC on 3 January 2019.
The burst signal was seen by all CGBM detectors.

The burst light curve shows two multi-peaked pulses which
start at T-6.9 sec, peak at T+5.4 sec, and end at T+22.3 sec.
The T90 and the T50 durations measured by the SGM data are
19.6 +- 2.5 sec and 9.1 +- 1.0 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1230584543/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.

A. A. Breeveld (UCL-MSSL) and A. Y. Lien (GSFC/UMBC) report on behalf of
the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190103B
103 s after the BAT trigger (Lien et al., GCN Circ. 23602
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 ).
No optical afterglow consistent with the XRT position (Evans et al. GCN
Circ. 23603
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 ) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding
chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           103          253          147         >20.5
u_FC               316          565          246         >19.5
white              103        23827         1860         >21.8
v                  646        40393         2202         >20.6
b                  571        46547         2987         >21.5
u                  316        46101         3922         >21.3
w1                4776        45188         3715         >21.2
m2                4570        41036         2792         >21.1
w2                4161        39480         1904         >21.0

The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.01 in the direction of the
burst (Schlegel et al. 1998).