GRB 171102B

T. N. Ukwatta (LANL), D. N. Burrows (PSU), A. D'Ai (INAF-IASFPA),
V. D'Elia (ASDC), Alex Deich (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 15:20:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 171102B (trigger=785510).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 288.103, +22.438 which is 
   RA(J2000) = 19h 12m 25s
   Dec(J2000) = +22d 26' 16"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 20 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~4 sec after the trigger. 

The XRT began observing the field at 15:22:33.3 UT, 123.8 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 288.07776, 22.44512 which is equivalent
to:
   RA(J2000)  = 19h 12m 18.66s
   Dec(J2000) = +22d 26' 42.4"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 87 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 4.51
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
124 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 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 18.0 mag. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.75. 

Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 
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.)

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

Using 1915 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 171102B, 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 = 288.07787, +22.44433 which is equivalent
to:

RA (J2000): 19h 12m 18.69s
Dec (J2000): +22d 26' 39.6"

with an uncertainty of 1.8 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.

S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia
(ASDC), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A. Tohuvavohu
(PSU) and T.N. Ukwatta report on behalf of the Swift-XRT team:

We have analysed 10 ks of XRT data for GRB 171102B (Ukwatta et al. GCN
Circ. 22082
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 ), from 110 s to 24.1 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.
22084
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 ).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.58 (+0.08, -0.11), followed by a break at T+5902 s to
an alpha of 1.32 (+0.43, -0.17).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.17 (+0.17, -0.16). The
best-fitting absorption column is  5.8 (+1.7, -1.3) x 10^21 cm^-2,
consistent with the Galactic value of 4.5 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 6.9 x 10^-11 (8.1 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     5.8 (+1.7, -1.3) x 10^21 cm^-2
Galactic foreground: 4.5 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.17 (+0.17, -0.16)

If the light curve continues to decay with a power-law decay index of
1.32, the count rate at T+24 hours will be 4.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.8 x
10^-13 (3.3 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/00785510.

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

GRB 171102B: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 171102B
125 s after the BAT trigger (Ukwatta et al., GCN Circ. 22082
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 ).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 22084
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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          4979         5129          147         >20.2
u_FC               125          375          246         >19.8
white             4979         5749          344         >20.5
v                  432        11930         1160         >19.3
b                  381        18368         1057         >20.5
u                  125        24106         2391         >21.5
w1                 481        23421         2042         >20.7
m2                 456        22515         1843         >21.3
w2                 407        11017         1179         >20.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.75 in the direction of the burst
(Schlegel et al. 1998).

S. Harita, R. Itoh, K. L. Muarata, Y. Tachibana, T. Yoshii, K. Morita, T.
Ozawa, H. Mamiya, K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB171102B (T. N. Ukwatta et
al., GCN Circular #22082
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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 2017-11-03 09:05:03.04 UT . 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
-------------------------------------------------------------------------------------------------------
~17.742       09:24:59           300          >18.2        >17.5
>16.9
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.

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-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 171102B (trigger #785510)
(Ukwatta et al., GCN Circ. 22082
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 ).  The BAT ground-calculated position is
RA, Dec = 288.096, 22.434 deg which is
   RA(J2000)  =  19h 12m 23.0s
   Dec(J2000) = +22d 26' 03.2"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 22%.

The mask-weighted light curve shows a weak pulse that starts at ~ T-6 s and
ends at ~ T+14 s. T90 (15-350 keV) is 17.8 +- 3.1 sec (estimated error including
systematics).

The time-averaged spectrum from T-6.18 to T+13.72 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.16 +- 0.24.  The fluence in the 15-150 keV band is 9.3 +- 1.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+3.51 sec in the 15-150 keV band
is 1.2 +- 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/785510/BA/

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), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report:

We observed the field of GRB 171102B (Ukwatta, et al., GCN 22082
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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 2017/11 3.14 to 2017/11 3.20 UTC (11.99 to
13.55 hours after the BAT trigger), obtaining a total of 0.98 hours
exposure in the r and i bands and 0.42 hours exposure in the Z, Y, J, and H
bands.

For a source within the Swift-XRT error circle (Osborne, et al., GCN
22084
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 ), in comparison with the USNO-B1 and 2MASS catalogs, we obtain the
following upper limits (3-sigma):

 r > 22.51
 i > 22.59
 Z > 21.14
 Y > 21.53
 J > 21.36
 H > 20.97

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

H.J. Tan (CCU), Z.P. Zhu, H.X. Feng, D. Xu (NAOC), Y.D. Hu (IAA-CSIC), 
X. Gao (Urumqi No.1 Senior High School) report:

We observed the field of GRB 171102B (Ukwatta et al., GCN 22082
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 ) using 
the 0.36m and 0.60m telescopes located at Nanshan, Xinjiang, China. All 
imaged were taken without filter.

Our photometry was summarized as follows:
========================================
Tmid(s)+T0  Telescope  Exptime(s)       UL(R)

389               36cm        40*3             >16.10

645               60cm        30*3             >17.80

1365             60cm        60*15           >18.55

========================================
Note: (1) Photometry is calibrated with stars (R2 magnitude) in the USNO 
B1 catalogue, although images were taken without filter.

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

We observed the field of the Swift  GRB 170822A   (Ukwatta et al.,
GCN  22082
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 ) with Zeiss-1000 1-m telescope of Tien Shan Astronomical 
Observatory starting on Nov., 02 (UT) 15:47:45.  We took several images 
in R-filter.  Within enhanced XRT error circle  (Osborne et al., GCN 
22084
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 ) we do not detect  any  object.  Preliminary  photometry of the 
afterglow is following.

Date       UT start   t-T0    Filter Exp.  OT     Err. UL
                      (mid, days)     (s)             (3 sigma)


2017-11-02 15:47:45  0.04377  R    30*120  n/d    n/d  20.1


Photometry is based on nearby USNO-B1.0 stars R2 magnitudes
USNO-B.1_id  R2
1124-0422739 16.70
1124-0422527 16.20
1124-0422440 15.76

E. Mazaeva (IKI),  R. Inasaridze (AbAO), A. Pozanenko (IKI),   A. 
Volnova  (IKI),   V. Ayvazian (AbAO),  O. Kvaratskhelia (AbAO), G. 
Inasaridze (AbAO), I. Molotov (KIAM) report on behalf of larger GRB 
follow-up  collaboration:

We observed the field of the Swift  GRB 170822A   (Ukwatta et al.,
GCN  22082
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 ) with AS-32 (0.7m) telescope of Abastumani Observatory 
starting on Nov., 02 (UT) 15:53:26. We obtained several unfiltered 
images of the field.   Within enhanced XRT error circle  (Osborne et 
al., GCN   22084
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 ) we do not detect  any  object.  Preliminary photometry 
of the field is following

Date        UT start  t-T0     Filter Exp.   OT   Err UpLim (3 sigma)
                       (mid, days)     (s)

2017-11-02 15:53:26   0.05497  CR     53*60  n/d  n/d 21.7

Photometry is based on nearby USNO-B1.0 stars R2 magnitudes
USNO-B.1_id  R2
1124-0422571 18.10
1124-0422577 17.52
1124-0422572 18.34
1124-0422730 17.80

A finding chart can be found at 
http://grb.rssi.ru/GRB171102B/GRB171102B_AAO_171102.png