GRB 151112A

J. Bolmer, F. Knust and J. Greiner (all MPE Garching) report on behalf
of the GROND team: 

We present further analysis of the GROND observations of GRB 151112A 
(Swift trigger 663179; Malesani et al., GCN #18588
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 ; Knust et al. GCN
#18595
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 ). 

After correcting for the galactic foreground E(B-V)=0.01 mag and 
fitting a power-law model to the 7-channel GROND SED from the first
night, 
we derive a photometric redshift of z = 4.1 +/- 0.3, according to the
g'- and r'-band 
dropouts with g'-r' > 1.5 mag and r'-i' = 0.9 mag. 

Based on the observed decay between the first and the second night we
predict an 
i'-band magnitude of ~24 mag for the coming night.

S. R. Oates (IAA-CSIC/UCL-MSSL) and D. Malesani (DARK/NBI)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 151112A
3144 s after the BAT trigger (Malesani et al., GCN Circ. 18588
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 ).
No optical afterglow, consistent with the enhanced XRT position
(Osborne et al. GCN Circ. 18592
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 ) and the GROND position 
(Knust et al., GCN Circ. 18595
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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          3144         3294          147         >21.3
white             3144         4527          344         >21.8
v                 3301         4938          393         >20.2
b                 4123        10985          349         >21.1
u                 3917        10825         1082         >21.5
w1                3711         9912         1169         >21.4
m2                3506        15760         1240         >21.3

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).

K. Yamaoka (Nagoya U.), H. Negoro, T. Masumitsu (Nihon U.),
S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA),
T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto,
T. Takagi, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech),
A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.),
M. Nakajima, K. Tanaka (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.),
Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.),
K. Yamaoka (Nagoya U.), M. Morii (ISM),
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source
at 13:45:24 UT. Assuming that the source flux was constant over the transit,
we obtain the source position at

(R.A., Dec) = (1.543 deg, -61.934 deg) = (00 06 10, -61 56 03) (J2000)

with a 90% C.L. statistical error of 0.25 deg and an additional systematic uncertainty
of 0.1 deg (90% containment radius).
This position is consistent with Swift GRB 151112A (Malesani et al., GCN Circ. 18588
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 ).
The X-ray flux averaged over the scan was 217 +- 31 mCrab
(4-10keV, 1 sigma error).
There was no significant excess flux in the previous transit at 12:12 UT
and in the next transit at 2015-11-12 15:17 UT with an upper limit of 20 mCrab for each.

F. Knust, T.-W. Chen and J. Greiner (all MPE Garching) report on behalf of
the GROND team:

We observed the field of GRB 151112A (Swift trigger 663179; Malesani et
al., GCN #18588
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 ) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at the ESO La
Silla Observatory (Chile).

Observations started at 00:09 UT on 2015-11-13, 10.5hrs after the GRB
trigger, and are continuing. They were performed at an average seeing of
1.8" and at an average airmass of 1.2.

We found a single point source within the 1.4" Swift-XRT error circle
reported by Osborne et al. (GCN #18592
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 ) at

RA (J2000.0) = 00h 08m 12.77s

DEC (J2000.0) = -61d 39' 48.4"

with an uncertainty of 0.5" in each coordinate.

Based on 11.50 min of total exposures in g'r'i'z' and 12.00 min in JHK, we
estimate preliminary magnitudes (all in AB system) of

g' > 23.9 mag,
r' = 23.9 +/- 0.373 mag,
i' = 22.4 +/- 0.169 mag,
z' = 22.5 +/- 0.288 mag,
J  > 21.0 mag,
H  > 20.5 mag, and
K  > 19.0 mag.


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)=0.01 mag in the
direction of the burst (Schlegel et al. 1998).

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

We have analysed 9.6 ks of XRT data for GRB 151112A (Malesani et al.
GCN Circ. 18588
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 ), from 3.1 ks to 33.0 ks after the  BAT trigger. The
data are entirely in Photon Counting (PC) mode. The enhanced XRT
position for this burst was given by Osborne et al. (GCN Circ. 18592
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 ).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.43 (+/-0.08).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.21 (+0.17, -0.16). The
best-fitting absorption column is  1.1 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 1.9 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 3.0 x 10^-11 (4.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     1.1 (+/-0.4) x 10^21 cm^-2
Galactic foreground: 1.9 x 10^20 cm^-2
Excess significance: 4.1 sigma
Photon index:	     2.21 (+0.17, -0.16)

If the light curve continues to decay with a power-law decay index of
0.43, the count rate at T+24 hours will be 0.040 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 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/00663179.

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

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI),
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-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 151112A (trigger #663179)
(Malesani, et al., GCN Circ. 18588
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 ).  The BAT ground-calculated position is
RA, Dec = 2.050, -61.680 deg which is
    RA(J2000)  =  00h 08m 11.9s
    Dec(J2000) = -61d 40' 46.7"
with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 52%.

The mask-weighted light curve shows several overlapping peaks, starting with a 
sharp rise peaking at T=0 sec, then a second peak at T+5 sec, a third at T+10 
sec and falling to background by T+20 sec. T90 (15-350 keV) is 19.32 +- 31.24 
sec (estimated error including systematics).

The time-averaged spectrum from T-0.06 to T+61.94 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.77 +- 0.21.  The fluence in the 15-150 keV band is 9.4 +- 1.2 x 10^-7 erg/cm2. 
The 1-sec peak photon flux measured from T-0.01 sec in the 15-150 keV band is 
1.9 +- 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/663179/BA/

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

Using 4055 s of XRT Photon Counting mode data and 6 UVOT
images for GRB 151112A, 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 = 2.05348, -61.66328 which is equivalent
to:

RA (J2000): 00h 08m 12.84s
Dec (J2000): -61d 39' 47.8"

with an uncertainty of 1.4 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.

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

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

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

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

O.Gress, K.Ivanov, N.M.Budnev, V.A.Poleshchuk
Irkutsk State University

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

V.Krushinski, I.Zalozhnih
Ural Federal University, Kourovka

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

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)

MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was pointed to the  GRB151112A at 2015-11-12 18:12:09 UT 
(~5.5 hours ater trigger). 
On our first (180s exposure)  set we did not  find optical transient within 
Swift error-box (Malesani et al., GCN #18588
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 ; Burrows et al., GCN #18589
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 ; ) 
brighter then 20.5.

The message may be cited.

S. R. Oates (IAA-CSIC, UCL-MSSL) reports on behalf of the UVOT team:

UVOT took a finding chart exposure of GRB 151112A, 150 seconds with the White filter
starting 3144 seconds after the BAT trigger (Malesani et al., GCN Circ. 18588
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 ). 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 (Burrows et al., GCN Circ. 18589
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 ). 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.

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

The XRT began observing the field of GRB 151112A at 14:37:09.1 UT,
3141.0 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 2.05651, -61.66273
which is equivalent to:
   RA(J2000)  = 00h 08m 13.56s
   Dec(J2000) = -61d 39' 45.8"
with an uncertainty of 3.6 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 (1.92 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3
(+2.37/-2.09) x 10^21 cm^-2 (90% confidence).

D. Malesani (DARK/NBI), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL),
K. L. Page (U Leicester), T. G. R. Roegiers (PSU) and
B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team:

At 13:44:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 151112A (trigger=663179).  Swift did not slew immediately 
to the burst. The BAT on-board calculated location is 
RA, Dec 2.045, -61.692 which is 
   RA(J2000) = 00h 08m 11s
   Dec(J2000) = -61d 41' 32"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a FRED-shaped 
profile with superimposed peaks and total duration of about 20 sec.  
The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+50.8
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is D. Malesani (malesani AT dark-cosmology.dk). 
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.)