GRB 170111A

A. P. Beardmore (U Leicester), D. N. Burrows (PSU), C. Gronwall (PSU),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 00:33:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 170111A (trigger=731887).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 20.717, -32.540 which is 
   RA(J2000) = 01h 22m 52s
   Dec(J2000) = -32d 32' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak
structure with a duration of about 40 sec.  The peak count rate
was ~700 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 00:35:14.8 UT, 106.7 seconds after
the BAT trigger. Using promptly downlinked data we find a variable, uncatalogued
X-ray source with an enhanced position: RA, Dec 20.6981, -32.5653 which
is equivalent to:
   RA(J2000)  = 01h 22m 47.56s
   Dec(J2000) = -32d 33' 55.1"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 107 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 in excess of the Galactic value (3.10 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.1
(+2.60/-2.25) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 112 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  approximately 70% 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 0.03. 

Burst Advocate for this burst is A. P. Beardmore (apb 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.)

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

Using 564 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 170111A, 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 = 20.69735, -32.56485 which is equivalent
to:

RA (J2000): 01h 22m 47.36s
Dec (J2000): -32d 33' 53.5"

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.

R.Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA) , National University of San 
Juan, Argentina

H. Levato, C. Saffe
Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE),
San Juan, Argentina

V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina,
A.V.Krylov, I.Gorbunov, P.Balanutsa, A.Kuznetsov, V.V.Chazov
Lomonosov Moscow State University, Sternberg Astronomical Institut of MSU

K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk
Irkutsk State University

V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk

A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik
Kislovodsk Solar Station of the Pulkovo Observatory

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-OAFA  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in OAFA (Argentina) was pointed to the  GRB170111.02 17 sec after 
notice time 
and 63 sec after trigger time at 2017-01-11 00:34:31 UT. On our first (10s 
exposure)  set we haven`t found optical transient  within SWIFT error-box 
(ra=20.7167 dec=-32.54 r=0.05).
The 5-sigma upper limit has been about 17.5 mag
The observations made on zenit distance = 25 degrees, galaxy latitude b = 
-81 degree.
The moon (97 % bright part) is 26 degrees above the horizon. The distance 
between  moon and  object is 84
Observations started at twilight.
The sun  altitude  is -9.8 degree.
The object can be observed till 2017-01-11 06:13:03.

  The 
message may be cited.

P.A. Evans (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU),
T.G.R. Roegiers (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U.
Leicester) and	report on behalf of the Swift-XRT team: report on
behalf of the Swift-XRT team:

We have analysed 6.2 ks of XRT data for GRB 170111A, from 96 s to 42.0
ks after the  BAT trigger. The data comprise 17 s in Windowed Timing
(WT) mode (the first 4 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode. 

The late-time light curve (from T0+5.1 ks) can be modelled with a
power-law decay with a decay index of alpha=0.72 (+/-0.18).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.68 (+0.17, -0.16). The
best-fitting absorption column is  3.6 (+0.9, -0.8) x 10^21 cm^-2, in
excess of the Galactic value of 3.1 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 4.6 x 10^-11 (6.1 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     3.6 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 3.1 x 10^20 cm^-2
Excess significance: 6.6 sigma
Photon index:	     1.68 (+0.17, -0.16)

If the light curve continues to decay with a power-law decay index of
0.72, the count rate at T+24 hours will be 0.020 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.5 x
10^-13 (1.2 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/00731887.

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

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 170111A
(GCN 20423
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 , Beardmore et al.) with a mid-exposure time of about
1 hour post-burst (2017-01-11 01:36 UT). Total summed exposure
times amounted to 36 minutes in I and 30 minutes in J.

No source is detected at the position of the X-ray
afterglow (GCN 20424
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 , Evans et al.) in either I or J,
to an approximate 3-sigma limiting magnitude of I > 21.9
(calibrated using USNO-B1.0 stars).

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester),

J. R. Cummings (CPI), N. Gehrels (GSFC), 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+739 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170111A (trigger #731887) (Beardmore, et al., GCN Circ. 20423
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 ). The BAT ground-calculated position is RA, Dec = 20.688, -32.541 deg which is RA(J2000) = 01h 22m 45.2s Dec(J2000) = -32d 32' 28.4" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%. The mask-weighted light curve shows a single, triangular shaped peak beginning at

T-20 sec, peaking at T+0 sec and ending at about T+10 sec. T90 (15-350 keV) is

29.9 +- 9.4 sec (estimated error including systematics).


The time-averaged spectrum from T-13.59 to T+25.32 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.64 +- 0.21.  The fluence in the 15-150 keV band is 8.1 +- 1.1 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+2.09 sec in the 15-150 keV band
is 0.9 +- 0.2 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/731887/BA/

P. D'Avanzo, D. Fugazza, S. Covino, A. Melandri (INAF/OAB) report on behalf of the REM team:

We observed the field of GRB 170111A (Beardmore et al., GCN 20423
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 ) with the 60-cm robotic 
telescope REM located at the La Silla Observatory (Chile). The observations started at 00:34:41 UT, 
73 seconds after the burst, and were carried out simultaneously in the g, r, i, z and H bands.

A preliminary photometry indicates that no source is detected at the X-ray afterglow position 
(Evans et al. GCN 20424
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 ) down to the following 3sigma limiting magnitudes:

r > 16.3 at T-T0 =  78s
H > 15.9 at T-T0 =  86s
r > 18.9 at T-T0 = 706s
H > 17.7 at T-T0 = 785s


Magnitudes are in the AB system and have been calibrated with respect to the 2MASS (H-band) 
and APASS (r-band) catalogues.

M.H. Siegel (PSU) and A. P. Beardmore (U Leicester) 
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170111A
111 s after the BAT trigger (Beardmore et al., GCN Circ. 20423
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 ).
No optical afterglow consistent with the XRT position
(Evans et al., GCN Circ. 20424
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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           111          261          147         >20.6
white              111          570          167         >20.7
v                  601          621           19         >18.0
b                  525          545           19         >19.6
u                  676          696           19         >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).