GRB 160203A

V. Zach Golkhou (ASU), 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
(GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Neil Gehrels (GSFC), Harvey
Moseley (GSFC), John Capone (UMD), and Vicki Toy (UMD) report:

We observed the field of GRB 160203A (D'Avanzo, et al., GCN 18979
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 ) 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 2016/02 6.28 to 2016/02 6.52 UTC (76.40 to
82.32 hours after the BAT trigger), obtaining a total of 4.27
hours exposure in the r, i, and z bands.

For a source within the Swift-XRT error circle (Osborne, et al.,
GCN 18983
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 ), in comparison with the USNO-B1 and 2MASS catalogs, we obtain
the following upper limits (3-sigma):

r    >  24.20
i    >  24.14
z   >  19.92

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.

Y.Ono, T.Fujiwara, T. Yoshii, Y. Saito, Y. Tachibana, H. Ohuchi, Y. Yano, S. Kurita, 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 160203A (P. D'Avanzo et al., GCN Circular #18979
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 ) 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 2016-02-03 15:46:41 UT (~13.5 h after the burst).
We did not find any new point source within XRT circle in all three bands.

We obtained following limits for the magnitudes.

T0+[hour]    MID-UT     T-EXP[sec]      g'         Rc          Ic
----------------------------------------------------------------------------
   15.98        18:12:04         10080       >21.0     >20.8    >20.1
----------------------------------------------------------------------------
T0+ : Elapsed time after the burst 
T-EXP: Total Exposure time 
We used GSC2.3 catalog for flux calibration.

Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP),
Boer, M., Laugier, R. (CNRS-ARTEMIS),
Gendre B. (UVI - Etelman Obs.),
Coward, D. McPherson, D. Williams A., Martin R.,
Moore J., Dodson R. (UWA) report:

We analysed the field of GRB 160203A detected by SWIFT
(trigger 672525) with the Zadko robotic telescope (D=100cm)
located at the observatory - Gingin, Australia.

The observations started 10.9h after the GRB trigger.
The elevation of the field increased from
23 degrees above horizon and weather conditions
were very good.

The first fast analysis (Boer et al. GCNC 18985)
can be now completed by late images. The stack
of images shows the afterglow. Measurements:

t1(s) t2(s)  Rmag   d_Rmag
44824 48920 22.30   0.50

Magnitudes are not corrected for galactic dust extinction.

S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), P. D'Avanzo (INAF-OAB),
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 160203A (trigger #672525)
(D'Avanzo, et al., GCN Circ. 18979
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 ).  The BAT ground-calculated position is
RA, Dec = 161.967, -24.772 deg, which is 
   RA(J2000)  =  10h 47m 52.2s 
   Dec(J2000) = -24d 46' 17.9" 
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 20%.
 
The mask-weighted light curve shows a single peak starting at ~T-1 sec,
peaking at ~T+13 sec, and ending at ~T+40 sec.  T90 (15-350 keV) is
20.2 +- 3.2 sec (estimated error including systematics).
 
The time-averaged spectrum from T+1.46 to T+25.78 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.93 +- 0.20.  The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+11.98 sec in the 15-150 keV band
is 1.3 +- 0.4 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/672525/BA/

A. Volnova (IKI), E. Mazaeva (IKI),  A. Kusakin (Fesenkov Astrophysical 
Institute),  A. Pozanenko (IKI) report on behalf of a larger GRB 
follow-up collaboration:

We observed the field of the Swift GRB 160203A (D'Avanzo et al., GCN 
18979
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 ) with Zeiss-1000 (West) 1-m telescope of Tien Shan Astronomical 
Observatory starting on Feb. 03 (UT) 20:31:45.  We obtained several 
images in R filter. We marginally (S/N ~ 2) detect afterglow  (Kruehler 
et al., GCN 18980
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 ) in a combined image. Preliminary photometry of the 
afterglow is following

Date       UT start    t-T0     Filter  Exp.    OT    Err
                        (mid, days)      (s)

2016-02-03 20:31:45    0.80045  R       21*300 23.0   0.5


The photometry is based on nearby USNO-B1.0 stars:

USNO-B1.0_id   R2
0652-0250834   18.04
0651-0249689   18.51

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 (GSFC/STScI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),
Jos�� A. de Diego (UNAM), Leonid Georgiev (UNAM), 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 160203A (D'Avanzo, et al., GCN 18979
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 ) 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 2016/02 4.36 to 2016/02 4.55 UTC (30.42 to
34.94 hours after the BAT trigger), obtaining a total of 3.27 hours
exposure in the r, i, and z bands.

For a source within the Swift-XRT error circle (Osborne, et al., GCN
18983
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 ), in comparison with the USNO-B1 and 2MASS catalogs, we obtain the
following detections and upper limit (3-sigma):

  r = 23.35 +/- 0.21
  i = 22.90 +/- 0.13
  z > 20.55

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.

A. Trotter, D. Reichart, J. Haislip, J. Moore, N. Frank, M. Maples, E. Johnson, R. Joyner, J. Martin, C. Salemi, J. A. Crain, K. Ivarsen, A. LaCluyze, and M. Nysewander report:

Skynet observed the Swift BAT/XRT localization of GRB 160203A (D'Avanzo et al., GCN 18979
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 , Swift trigger=672525) with with one 16" telescope (P5) and two 24" telescopes (P1 and P8) of the PROMPT array at CTIO, Chile. Starting at 2016-02-03 02:17:18 UT and continuing until 09:26 UT (t=4.1m-7.2h post-trigger), Skynet took a total of 353 exposures ranging from 20-160s. Between t=4.1m and t=61m, both P5 and P8 observed in the I band. Between t=78m and t=7.2h, P1 cycled through the V, R and I filters, while P8 cycled through the B, V and R filters.

We clearly detect an optical afterglow at the position first reported by Kruehler et al. (GCN 18980
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 ). The OT exhibits a rising light curve at early times, peaking at I~17 at t~8m, and fades thereafter, with I~20 at t~5h.

A preliminary light curve is at:
http://www.skynet.unc.edu/grb/grb160203a.png

Magnitudes are in the Vega System, calibrated to 8 APASS DR9 stars in the field.  Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.06 (Schlafly & Finkbeiner 2011).

No further Skynet observations are scheduled.

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. D'Elia
(ASDC), A. D'Ai (INAF-IASFPA), T.G.R. Roegiers (PSU), L.M. McCauley
(PSU), J.A. Kennea (PSU), C. Pagani (U. Leicester) and P. D'Avanzo
report on behalf of the Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 160203A (D'Avanzo et al. GCN
Circ. 18979
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 ), from 122 s to 33.8 ks after the  BAT trigger. The data
comprise 7 s in Windowed Timing (WT) mode (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.
18983
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 ).

The late-time light curve (from T0+4.9 ks) can be modelled with a
power-law decay with a decay index of alpha=1.15 (+0.24, -0.23).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.76 (+0.23, -0.22). The
best-fitting absorption column is  1.5 (+2.6, -1.5) x 10^22 cm^-2, at a
redshift of 3.52, in addition to the Galactic value of 7.4 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 3.8 x
10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Galactic foreground: 7.4 x 10^20 cm^-2
Intrinsic column:    1.5 (+2.6, -1.5) x 10^22 cm^-2 at z=3.52
Photon index:	     1.76 (+0.23, -0.22)

If the light curve continues to decay with a power-law decay index of
1.15, the count rate at T+24 hours will be 2.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (1.2 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/00672525.

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

Boer, M., Laugier, R. (CNRS-ARTEMIS), Klotz A., Turpin D., Atteia J.L. 
(CNRS-OMP-IRAP), Gendre B. (UVI - Etelman Obs.), Coward, D. McPherson, 
D. Williams A., Martin R., Moore J., Dodson R. (UWA) report:

The position of GRB 160203A (d'Avanzo et al., GCNC 18979) was observed 
with TAROT-Calern (TCA France), TAROT-Chile (TCH), and Zadko (W. 
Australia). Observing conditions where good for TCH and Zadko, with 
absorption for TCA.
The observations have started at
TCH: 2:16:24.7 UT, T0+3m14s
TCA: 2:16:28 UT, T0+ 3m18
Zadko: 13:04:33 UT, T0+10h52m

No source has been detected at the position of the reported afterglow 
(GCNC 18980, 18981, 18982, 18984). R limiting magnitude are 16.3 for 
TCA, 17.2 for TCH and 19.5 for Zadko.
At the time of writing Zadko is still observing the source position.

This notice is citable.

A. A. Breeveld (UCL-MSSL) and P. D'Avanzo (INAF-OAB) report on behalf of 
the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160203A 
151 s after the BAT trigger (D'Avanzo et al., GCN Circ. 18979
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 ).
A fading source consistent with the optical position (Kruehler et al. 
GCN Circ. 18980
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 ) is detected in the initial UVOT exposures in the white 
filter.

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           151          301          147         20.56 �� 0.3
white            10022        10928          885         21.9 �� 0.3
b                 4946         5146          197        >20.7
u                  309          472          160        >19.5
v                 5562         5762          197        >19.7
uvw1              5972         6171          197        >19.7
uvm2              5766         5966          197        >19.6
uvw2              5357         5557          197        >19.9

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.07 in the direction of the 
burst (Schlegel et al. 1998).

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

Using 310 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 160203A, 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 = 161.95125, -24.78914 which is equivalent
to:

RA (J2000): 10h 47m 48.30s
Dec (J2000): -24d 47' 20.9"

with an uncertainty of 2.0 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.

G. Pugliese (API/UvA), S. Covino (INAF/OAB), T. Kruehler (MPE Garching), D. Xu (NAOC/CAS), 
N. R. Tanvir (Leicester), report on behalf of a larger collaboration:

We observed the afterglow of GRB 160203A (D'Avanzo et al., GCN 18979
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 ;
Kruehler et al., GCN 18980
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 ; Xu, GCN 18981
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 ) with ESO's Very Large
Telescope UT2 equipped with X-shooter. Our observations were performed
in Rapid Response Mode and started at 02:31:35 UT on 03-02-2016, just about 
18 min after the Swift trigger. The X-shooter spectra cover the range between 
3000 and 23000 AA, and were obtained at a seeing of around 0.8".

A preliminary analysis of the spectrum shows a clear continuum with
absorption features due to Lyman-alpha and various metal lines (SII 1254, SiII 1259/60, OI 1302, 
SiII 1304, CII 1334, Si IV 1393/1402, SiII 1526, CIV 1548/1550, FeII 1608, AlII 1670) at a common 
redshift of 3.52, which we propose as the redshift of the GRB. 
We also detect an intervening system at z=2.203.

We acknowledge the fast and efficient support provided by Paranal staff. In particular we thank Dimitri 
Gadotti, Boris Haeussler, and Marcela Espinoza for their excellent job.

D. Xu (NAOC/CAS) reports on behalf of a large collaboration:

We observed the field of GRB 160203A (D'Avanzo et al., GCN 18979
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 ) using 
the LCOGT-1m located at Cerro Tololo. Observations started at 02:35:09 
UT on 2016-02-03 (i.e., 1319 s after the BAT trigger) and 10x150s R-band 
frames were obtained.

We detect an uncatalogued and decaying source at the position reported 
by Kruehler et al. (GCN 18980
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 ), which has m(R)= 18.04 in the first 150s 
exposure, calibrated with the nearby USNN star, #0651-0249724 
(R1=R2=16.84 mag). The fading nature confirms the source is the 
afterglow of GRB 160203A.

T. Kruehler (MPE Garching), D. A. Kann (TLS Tautenburg), J. Greiner (MPE
Garching), and J. Bolmer (MPE Garching) report on behalf of the GROND
team:

We observed the field of GRB 160203A (Swift trigger 672525; D'Avanzo et
al., GCN #18979
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 ) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla
Observatory (Chile).

Observations started at 02:18:58 UT on 2016-02-03, 6 min after the GRB
trigger, and are continuing. They were performed at an average seeing of
1".2 and at an average airmass of 1.8.

We found a single point source within the 2".3 Swift-XRT error circle at

RA (J2000.0) = 10:47:48.35
Dec. (J2000.0) = -24:47:19.8

with an uncertainty of 0".5 in each coordinate.

Based on the first 4.40 min of total exposures in g'r'i'z' and 4.0 min in
JHK at a mid-time of 02:22:14, we estimate preliminary magnitudes (all in
AB system) of

g' = 18.9 +/- 0.1 mag,
r' = 18.0 +/- 0.1 mag,
i' = 17.7 +/- 0.1 mag,
z' = 17.6 +/- 0.1 mag,
J  = 17.0 +/- 0.1 mag, and
H  = 16.7 +/- 0.1 mag.

While we cannot establish fading yet, we propose this source to be the
afterglow of GRB 160203A.

Given magnitudes are calibrated against GROND zeropoints as well as 2MASS
field stars and are not corrected for the expected Galactic foreground
extinction corresponding to a reddening of E_(B-V) = 0.06 mag in the
direction of the burst (Schlafly & Finkbeiner 2011).

P. D'Avanzo (INAF-OAB), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
F. E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB),
D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 02:13:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160203A (trigger=672525).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 161.952, -24.762, which is 
   RA(J2000)  =  10h 47m 48s
   Dec(J2000) = -24d 45' 43"
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 25 sec.  The peak count rate
was ~500 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 02:15:27.8 UT, 137.3 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 161.9511,
-24.7887 which is equivalent to:
   RA(J2000)  = 10h 47m 48.27s
   Dec(J2000) = -24d 47' 19.2"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 96 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. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 7.41
x 10^20 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 139 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 none 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
0.07. 

Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.inaf.it). 
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.)