GRB 191106A

F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), M. G. Bernardini (INAF-OAB),
D. N. Burrows (PSU), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC),
P. A. Evans (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU),
N. J. Klingler (PSU), S. J. LaPorte (PSU), A. Melandri (INAF-OAB),
P. T. O'Brien (U Leicester), K. L. Page (U Leicester),
M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 14:15:23 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 191106A (trigger=933515).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 269.350, +46.052, which is 
   RA(J2000)c =  17h 57m 24s
   Dec(J2000) = +46d 03' 06"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a few peaks
with a total duration of about 5 sec.  The peak count rate
was ~2800 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 14:16:34.2 UT, 70.3 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source with an enhanced position: RA, Dec 269.3349,
46.0346 which is equivalent to:
   RA(J2000)  = 17h 57m 20.38s
   Dec(J2000) = +46d 02' 04.7"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 73 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 (4.38 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 4
(+4.05/-3.32) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
130 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 100% of the
XRT error circle. The typical 3-sigma upper limit has been about 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.06. 

Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). 
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/)

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tiurina,P.Balanutsa,A.Kuznetsov,V.Vladimirov, D. Vlasenko, I.Gorbunov,
D.Zimnukhov, A.Pozdnyakov, E.Minkina, V.Senik (Lomonosov Moscow State University, SAI,Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA),
H. Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
D. Buckley(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova(Irkutsk State University, API),
A. Tlatov, D. Dormidontov(Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University),

MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)
started Swift GRB 191106A (Marshall et al. GCN 26177
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 ) alert observation 19 sec after at 2019-11-06 14:16:03 UT.

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory)
was pointed to the  GRB191106.59 19 sec after notice time (39 sec after trigger time)
  at 2019-11-06 14:16:03 UT at sunset (sun  altitude  is -8.5 deg.).

There is no OT with 5-sigma upper limit  14.0 mag at  2019-11-06 14:38:00UT.

Error-box galactic latitude b = 28 deg., longitude l = 73 deg.
The observations made on zenith distance = 27 deg.The moon (70 % bright part) is 26 deg. above the horizon.
The distance between  moon and  object is 87 deg.
The error-box can be observed till sunrise at 2019-11-07 03:49:40

MASTER-Amur was pointed to GRB 191106A 20 sec after notice time (41s after trigger time) 
at 2019-11-06 14:16:05 UT, but there are clouds.

The message may be cited.

Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado (IAA-CSIC), C. Perez 
del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga), S. Guziy (Univ. 
of Nikolaev) and D. Xiong, Y. Fan, X. Zhao, J. Bai, C. Wang, Y. Xin 
(Yunnan National Astronomical Observatory) on behalf of a larger 
collaboration, report:

Following the detection of GRB 191106A by Swift (Marshall et al. GCNC 
26177), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical 
Observatory (China) gathered images starting at 14:21 UT (~5.7 min after 
trigger). No optical afterglow is found down to 20.7 mag (unfiltered 
images) within the Swift/XRT error box, consistent with the 
non-detections by Swift/UVOT (Marshall et al. GCNC 26177) and MASTER 
(Lipunov et al. GCNC 26178). Observations are ongoing.

We thank the staff at Lijiang Astronomical Observatory for their 
excellent support.

S. Belkin (IKI), E. Klunko (ISTP), A. Pozanenko (IKI), E. Mazaeva (IKI), 
A. Volnova    report   on behalf of IKI-GRB-FuN:

We observed the field of  GRB 191106A (Marshall et al.  GCN 26177
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 ) with 
AZT-33IK telescope of Sayan observatory (Mondy) starting on Nov. 06 (UT) 
  14:24:30, i.e. ~11 minutes after GRB trigger.   We  do not detect any 
optical object in the XRT error circle  (Marshall et al.  GCN 26177
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 ). 
Preliminary photometry of the field  is following.

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

2019-11-06 14:24:30    0.03688    R      22*120  n/d      22.0


Photometry is based on the USNO-B2.0 nearby stars.

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA),
A. Tohuvavohu (U. Toronto), J.A. Kennea (PSU), B. Sbarufatti (PSU) and
F.E. Marshall report on behalf of the Swift-XRT team:

We have analysed 6.3 ks of XRT data for GRB 191106A (Marshall et al.
GCN Circ. 26177
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 ), from 106 s to 13.2 ks after the  BAT trigger. The
data are entirely in Photon Counting (PC) mode. The best available XRT
position  (using the promptly downlinked event data, the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue) is
RA, Dec = 269.3356, 46.0353 which is equivalent to:

RA (J2000): 17 57 20.55
Dec(J2000): +46 02 06.9

with an uncertainty of 2.3 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=3.37 (+0.33, -0.30).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.1 (+/-0.6). The
best-fitting absorption column is  3.1 (+3.1, -2.1) x 10^21 cm^-2, in
excess of the Galactic value of 4.4 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 3.7 x 10^-11 (5.6 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:	     3.1 (+3.1, -2.1) x 10^21 cm^-2
Galactic foreground: 4.4 x 10^20 cm^-2
Excess significance: 2.1 sigma
Photon index:	     2.1 (+/-0.6)

If the light curve continues to decay with a power-law decay index of
3.37, the count rate at T+24 hours will be 7.4 x 10^-10 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x
10^-20 (4.1 x 10^-20) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00933515.

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

Z.P. Zhu, D. Xu (NAOC), J. Viuho (NOT) report on behalf of a larger 
collaboration:

We observed the field of GRB 191106A (Marshall et al., GCN 26177
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 ) using 
the Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. 
Observations started at 19:35:51 UT on 2019-11-06 (i.e., 3.35 hr after 
the BAT trigger), and 16x200s Sloan z-band frames were obtained.

No optical source is detected in our stacked image at the XRT position 
(Page et al., GCN 26190
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 ), down to a limiting magnitude of z > 22.0 at a 
mean time of 4.0 hr post-burst, calibrated with the nearby SDSS field.

S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), F. E. Marshall (NASA/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-61 to T+242 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 191106A (trigger #933515)
(Marshall et al., GCN Circ. 26177
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 ).  The BAT ground-calculated position is
RA, Dec = 269.356, 46.046 deg which is
   RA(J2000)  =  17h 57m 25.4s
   Dec(J2000) = +46d 02' 44.7"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 95%.

The mask-weighted light curve shows many overlapping pulses. The burst
emission
starts at ~T-1.3 s and ends at ~T+2.4 s. T90 (15-350 keV) is 3.42 +- 0.35
sec
(estimated error including systematics).

The time-averaged spectrum from T-1.31 to T+2.38 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.89 +- 0.17.  The fluence in the 15-150 keV band is 3.2 +- 0.3 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T-0.02 sec in the 15-150 keV band
is 1.1 +- 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/933515/BA/

S. R. Oates (U.Warwick) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 191106A
132 s after the BAT trigger (Marshall et al., GCN Circ. 26177
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 ).
No optical afterglow consistent with the XRT position
(Page et al., GCN Circ. 26190
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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          4987         5137          147         >20.0
u_FC               132          381          246         >20.1
white             4987         6775          541         >21.0
v                  437         7186          549         >19.9
b                  387        12533         1264         >21.3
u                  132        11621         1631         >20.8
w1                 486         7510          464         >20.0
m2                 461         7391          510         >20.0
w2                 412        13245         1223         >20.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).

R. Gaikwad, S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed a weak detection of a GRB 191106A, which was also detected by Swift (Marshall F. E. et al., GCN # 26177), MASTER (Lipunov V. et al., GCN # 26178), BOOTES-4/MET (Hu Y.-D. et al., GCN # 26179), Mondy (Belkin S. et al., GCN # 26180), Swift-XRT (Page K. L. et al., GCN # 26190), NOT (Zhu Z. P. et al., GCN # 26191), Swift/BAT (Barthelmy S. D. et al., GCN # 26198) and Swift/UVOT (Oates S. R. et al., GCN # 26199).

The source was detected in the 40-200 keV energy range. The light curve showed single pulse of emission peaking at 2019-11-06 14:15:23.0 UT. The measured peak count rate associated with the burst is 134 cts/s above the background in the combined data of four quadrants, with a total of 408 cts. The local mean background count rate was 502 cts/s. Using cumulative rates, we measure a T90 of 3.6 s.

It was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.