GRB 160712A

M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
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 160712A (trigger #704155)
(Hagen, et al., GCN Circ. 19684
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 ).  The BAT ground-calculated position is
RA, Dec = 304.166, -26.965 deg which is
  RA(J2000)  =  20h 16m 39.9s
  Dec(J2000) = -26d 57' 52.8"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 24%.

The mask-weighted lightcurve shows the burst starting at ~T-5 sec, with a spike
at ~T0 sec, extending past T+95 sec where the data ends when the burst position
moves out of the BAT FOV due to a slew.

The time-averaged spectrum from T-8.60 to T+45.46 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.18 +- 0.13.  The fluence in the 15-150 keV band is 2.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.06 sec in the 15-150 keV band
is 2.4 +- 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/704155/BA/

T. Kruehler and J. Greiner (all MPE Garching) report on behalf of the
GROND team:

We re-observed the field of GRB 160712A (Swift trigger 704155; Hagen et
al., GCN #19684
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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 the
ESO La Silla Observatory (Chile).

Observations started at 04:38:43 UT on 2016-07-14, 32.8 hr after the GRB
trigger, and consisted of multiple exposures with a total integration
time of around 80 minutes. The average seeing and airmass were 2���.0 and
1.0, respectively.

Within photometric errors, no variability is detected with respect to
our earlier observations (GCN 19693
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 , see also Troja et al. GCN 19695
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 ).
The source is hence unlikely to be the afterglow of GRB 160712A.

L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160712A
3998 s after the BAT trigger (Hagen et al., GCN Circ. 19684
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 ). No
optical afterglow consistent with the XRT position (Beardmore et al.,
GCN Circ. 19690
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 ) or the possible optical afterglow candidate (Kruehler
et al., GCN Circ. 19693
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 ; Troja et al., GCN Circ. 19695
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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 exposures are:

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

white             3998         4148          147        >20.47
v                 4154         4354          196        >19.04
b                 4974         5027           52        >19.17
u                 4769         4969          196        >19.66
uvw1              4564         4764          196        >19.58
uvm2              4359         4559          196        >19.52

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).

Eleonora Troja (GSFC), 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), 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 160712A (Hagen, et al., GCN 19684
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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
2016/07 13.21 to 2016/07 13.42 UTC (9.05 to 14.30 hours after the
BAT trigger), obtaining a total of 3.56 hours exposure in the r
and i bands and 1.45 hours exposure in the Z, Y, J, and H bands.

We detect a source slightly outside of the XRT error circle
(Beardmore, et al., GCN 19690
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 ), and consistent with the GROND
position (Kruehler, et al., GCN 19693
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 ). In comparison with the
USNO-B1 and 2MASS catalogs, we obtain the following detections:

   r    22.77 +/- 0.08
   i    21.55 +/- 0.03
   Z    20.93 +/- 0.05
   Y    20.44 +/- 0.05
   J    20.27 +/- 0.06
   H    20.15 +/- 0.08

These magnitudes are in the AB system and are not corrected for
Galactic extinction in the direction of the GRB.
Further observations to determine whether the source is fading
are planned.

We thank the staff of the Observatorio Astron��mico Nacional in
San Pedro M��rtir.

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

The long GRB 160712A (Swift/BAT observation: Hagen et al., GCN 19684
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 )
triggered Konus-Wind at T0=71621.420 s UT (19:53:41.420).

The light curve statrs with a short spike followed
by a gradually decaying emission.
The total duration of the burst is ~25 s.
The emission is seen up to ~4 MeV.

As observed by Konus-Wind, the burst had a fluence of
(6.5 �� 2.0)x10^-6 erg/cm2 and a 64-ms peak energy flux,
measured from T0+0.128, of (2.7 �� 0.8)x10^-6 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+16.640 s)
is best fit in the 20 keV - 4 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.17(-0.57,+0.87),
and the peak energy Ep = 460(-117,+204) keV,
chi2 = 72/73 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep with only an upper limit on beta of -2.3,
chi2 = 72/72 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB160712_T71621/

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.

T. Kruehler and J. Greiner (all MPE Garching) report on behalf
of the GROND team:

We observed the field of GRB 160712A (Swift trigger 704155; Hagen et
al., GCN #19684
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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 the
ESO La Silla Observatory (Chile).

Observations started at 03:18:21 UT on 2016-07-13, 7.4 hr after the GRB
trigger. They were performed at an average seeing of 2���.2, at an
average airmass of 1.1, and severely affected by passing clouds.

We found a single source sightly outside of the XRT errorcircle at:

RA (J2000.0) = 20:16:38.50
Dec. (J2000.0) = -26:57:30.7

with an uncertainty of 0".5 in each coordinate. The distance to the
center of the XRT error circle (90% confidence radius 1".5 arcsec)
is 2".2.

Based on images with 24.2 min of total exposure in g'r'i'z'
and 24.0 min in JHK at a mid-time of 03:57:19 UT on 2016-07-13,
we derive the following preliminary magnitudes and upper limits
(all in AB system):

g > 23.3 mag
r = 22.9 +- 0.3 mag
i = 21.7 +- 0.3 mag
z = 21.4 +- 0.3 mag
J = 20.5 +- 0.2 mag
H = 20.2 +- 0.2 mag
K = 20.0 +- 0.3 mag

Given magnitudes are calibrated against USNO as well as 2MASS
field stars and are not corrected for the expected Galactic foreground
extinction corresponding to a reddening of E_(B-V) = 0.065 mag in the
direction of the burst (Schlafly & Finkbeiner 2011).

No statement about variability can be made at this point. Given its
position somewhat outside of the XRT error circle, it is uncertain
whether this source is related to GRB 160712A.

S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Maselli 
(INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU) and L. M. Z. Hagen (PSU) report on behalf of the
Swift-XRT team:

We have analysed 3.8 ks of XRT data for GRB 160712A (Hagen et al. GCN
Circ. 19684
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 ), from 4.0 ks to 17.2 ks after the	BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Beardmore et al. (GCN Circ. 19690
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 ).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.51 (+0.25, -0.22).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.91 (+0.28, -0.26). The
best-fitting absorption column is  2.8 (+1.3, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 8.3 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 (5.3 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     2.8 (+1.3, -1.1) x 10^21 cm^-2
Galactic foreground: 8.3 x 10^20 cm^-2
Excess significance: 3.0 sigma
Photon index:	     1.91 (+0.28, -0.26)

If the light curve continues to decay with a power-law decay index of
1.51, the count rate at T+24 hours will be 2.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.9 x
10^-14 (1.1 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/00704155.

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

A. Trotter, J. Haislip, D. Reichart, A. Verveer, T. Spuck, J. Moore, N. Frank, M. Maples, D. Dutton, R. Gao, R. Joyner, J. Martin, M. Paggen, J. A. Crain, K. Ivarsen, A. LaCluyze, M. Nysewander, B. Barlow, J. LaCluyze, L. Lanier, D. Moffett, B. Tobias, G. Bennett, J. Da Rocha, M. Dryzer, D. Dutton, J. Elliott, C. Ferguson, R. J. Hegedus, E. Lutz, B. McCormack, T. Melo, K. Otto, R. Pierce, S. Simon, E. Smith, J. Taylor, M. Tierney, D. Varvir, and A. Vasquez Soto report:

Skynet observed the Swift BAT/XRT localization of GRB 160712A (Hagen et al., GCN 19684
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 , Swift trigger=704155) with the 14" R-COP telescope at Perth Observatory, Australia. Starting at 2016-07-12 19:58 UT and continuing until 20:30 UT (t=4.3m-31.4m post-trigger), Skynet took a total of 17 20-160s exposures in the B, V, R, and I bands. We stacked subsets of these images to maximize the S/N ratio, and detected no optical source in any band at the XRT position.  Our 3-sigma limiting magnitudes are:

====================
tmid  fil  limit
====================
23m   B   >16.7
26m   V   >17.2
23m   R   >17.7
29m   I   >16.9
====================

Limiting magnitudes are in the Vega System, calibrated to 5 APASS stars in the field.  Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.07 (Schlafly & Finkbeiner 2011).

No further Skynet observations are scheduled.

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

Using 1053 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 160712A, 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 = 304.15987, -26.95819 which is equivalent
to:

RA (J2000): 20h 16m 38.37s
Dec (J2000): -26d 57' 29.5"

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.

L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team:

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 3998 seconds after the BAT trigger (Hagen et al., GCN Circ.
19684
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 ). 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 (Kennea et al., GCN Circ. 19686
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 ). 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 0.08.

J.A. Kennea (PSU), G. Cusumano (INAF-IASF PA), M. Perri (ASDC), P.A.
Evans (U. Leicester), J.P. Osborne (U. Leicester) and D.N. Burrows
(PSU) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 160712A at 20:47:52.7 UT,
3256.7 seconds after the BAT trigger. The position determined from
promptly downlinked data differs significantly from the on-board
position, suggesting that the XRT may have centroided on a cosmic ray;
the initial XRT position notice should be treated with caution. Using
promptly downlinked data we find an uncatalogued X-ray source with an
enhanced position: RA, Dec 304.1600, -26.9582 which is equivalent to:
   RA(J2000)  = 20h 16m 38.40s
   Dec(J2000) = -26d 57' 29.4"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 89 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 (8.30 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.7
(+2.97/-2.55) x 10^21 cm^-2 (90% confidence).

D.Buckley, S. Potter, A.Kniazev, M.Kotze
South African Astronomical Observatory

E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov,
P.Balanutsa,  A.Kuznetsov, D.Kuvshinov,
Lomonosov Moscow State University, Sternberg Astronomical Institute

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

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

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

V.Yurkov, Yu.Sergienko, A.Gabovich, E.Sinyakov
Blagoveschensk Educational State University, Blagoveschensk

Ricardo Podesta, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the  GRB160712.83 26 sec after notice time 
and 48 sec after trigger time at 2016-07-12 19:54:28 UT. On our first (10s 
exposure)  set we haven`t found optical transient  within SWIFT error-box 
(ra=20 16 35 dec=-26 58 52 r=0.050000).
The 5-sigma upper limit has been about 16.7 mag
The message may be cited.


The message may be cited.

L. M. Z. Hagen (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
S. B. Cenko (GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL)
and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 19:53:36 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 160712A (trigger=704155).  Swift did not slew immediately
due to an observational constraint. 
The BAT on-board calculated location is 
RA, Dec 304.149, -26.981 which is 
   RA(J2000) = 20h 16m 36s
   Dec(J2000) = -26d 58' 52"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a long burst with 
a duration of ~ 20 s and containing a short spike. The peak count rate 
was ~4500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+47.3
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is L. M. Z. Hagen (lea.zernow.hagen 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.)