GRB 181222B

A. Tohuvavohu (PSU), A. D'Ai (INAF-IASFPA), M. Siegel (PSU), J.A.
Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester),
A. Melandri (INAF-OAB), and P.A. Evans (U. Leicester) report on behalf
of the Swift-XRT and Swift-UVOT teams:

Swift has performed follow-up observations of the MASTER optical
transient J204928.79+245744.0  (V. Lipunov et al. GCN Circ. 23588
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 ),
within the IPN localization region of Fermi/GBM and Konus detected GRB
181222B (P. Veres GCN Circ. 23551
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 , D. Svinkin et al. GCN Circ. 23556
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 ).

Swift/XRT collected 3.9 ks of Photon Counting (PC) mode data between
T0+414.9 ks and T0+427.0 ks. No X-ray source was detected at the MASTER
position with an upper limit of 2.4 e-3 ct s^-1.

Two uncatalogued X-ray sources have been detected in the field during
this observation.  Both sources are below the RASS limit and show no
definitive signs of fading. Given the large localization region of this
burst and the amount of time elapsed between the GRB and these
observations, we believe it unlikely that these X-ray sources are
related to the GRB.
Details of the sources are given below:

Source 1:
 RA (J2000.0): 312.2708 = 20:49:52.88
 Dec (J2000.0): +25.0419= +25:02:30.9
 Error: 2.5 arcsec (radius, 90% conf.)
 Count-rate (9.9 [+2.0, -1.9])e-3 ct s^-1
 Distance: 7.2 arcminutes from MASTER position.
 Flux: (2.3 [+0.5, -0.4])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000.0):  312.3700  =  20:49:28.81
  Dec (J2000.0): +24.9769  =  +24:58:37.0
  Error: 7.7 arcsec (radius, 90% conf.)
  Count-rate: (3.03 [+1.21, -0.97])e-3 ct s^-1	 
  Distance: 53 arcsec from MASTER position.
  Flux: (1.22 [+0.49, -0.39])e-13 erg cm^-2 s^-1 (observed, 0.3-10
keV).

Swift/UVOT began observing the field in the White filter 414 ks after
the GRB trigger. We do not find any optical source at the MASTER
position, with an upper limit of 21.48 +/- 0.22 magnitude (AB) in a 
3094 second exposure.  This magnitude is not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.24 in the direction of
the burst (Schlegel et al. 1998).

The results of the XRT-team automatic analysis of the XRT observations,

including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020850/.

This circular is an official product of the Swift team.

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a ToO observation of the Fermi+MASTER GRB 181222B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020850

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi+MASTER event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

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

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina,  P.Balanutsa,
A.Kuznetsov, D. Vlasenko, D.Kobtsev
Lomonosov Moscow State University, SAI

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

D. Buckley,
South African Astronomical Observatory

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

O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev,
Irkutsk State University

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

R. Podesta, C.Lopez, F. Podesta
Observatorio Astronomico Felix Aguilar (OAFA)

H. Levato
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

The Global MASTER network continues to inspect error box of the short
bright gamma-ray burst GRB 181222B (Veres, GCN #23551
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 ; Lipunov et al.,
GCN #23552
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 )

MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,
vol. 2010, 30L) located in Spain (IAC Teide Observatory)
started inspect survey of  Fermi GRB18122B   IPN
error-box (Svinkin et al., GCN #23556
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 )
36801 sec after notice time and 36801 sec after trigger time
at 2018-12-24 19:07:42 UT.
  There are 479 galaxies in IPN localization.

MASTER auto-detection system found optical transient:

MASTER OT J204928.79+245744.0 detection.

MASTER-IAC auto-detection system discovered OT source at
(RA, Dec)=20h 49m 28.79s +24d 57m 44.0s on 2018-12-24.81773 UT.
The OT unfiltered magnitude is 16.9m (limit 18.6m).

The OT is seen in 2 images. There is no minor planet at this place.
We have reference image without OT on 2018-08-02.04970 UT with 18.7m unfiltered magnitude limit .
There is red start in PanSTARR (rmag=21.7) and SDSS.9 (r=21.9)
Spectral observations are required.


Observations started at twilight.The sun  altitude was -11.5 deg.
The observations made on zenit distance = 29 deg.
The moon (94 % bright part) below the horizon
The altitude of the Moon is -14 deg.
The object can be observed till 2018-12-25 00:54:38.
The galactic latitude b = -60 deg., longitude l = 98 deg.

MASTER-Amur robotic telescope  located in Russia (Blagoveshchensk State
Pedagogical University) was pointed to the  FERMI GRB181222B 46503 sec
after trigger time at 2018-12-23 09:06:40 UT, with upper limit up to  17.8
mag. Observations started at twilight.  The observations began at zenit
distance = 44 deg. The sun  altitude  is -14.2 deg.

MASTER-Tunka robotic telescope  located in Russia (Applied Physics
Institute, Irkutsk State University) was pointed to the  FERMI
GRB181222B 52255 sec after trigger time at 2018-12-23 10:42:32 UT, with
upper limit up to  18.6 mag. Observations started at twilight.  The
observations began at zenit distance = 44 deg. The sun  altitude  is -14.5
deg.


The cover map is available at
https://master.sai.msu.ru/site/master2/observ.php?id=890715


The message may be cited.

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

The short-duration, extremely bright GRB 181222B
(Fermi-GBM detection: Veres, GCN Circ. 23551
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 ;
IPN triangulation: Svinkin et al., GCN Circ. 23556
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 )
triggered Konus-Wind at T0=72694.563 s UT (20:11:34.563).

The burst light curve shows a single pulse
which starts at about T0 and has a total duration of ~2.1 s.
The emission is seen up to ~15 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB181222_T72694/

As observed by Konus-Wind, the burst
had a fluence of 3.70(-0.17,+0.18)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.166 s,
of 2.72(-0.25,+0.26)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+0.512 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.52(-0.08,+0.08),
the high energy photon index beta = -2.95(-0.30,+0.20),
the peak energy Ep = 365(-26,+27) keV
(chi2 = 53/56 dof).

Among ~300 bursts from the Konus catalog of short GRBs
(Svinkin et al., ApJS 224, 10, 2016), GRB 181222B is within top 2%
in the terms of 16-ms peak energy flux and within top 2% in the terms
of the total energy fluence, both in the 20 keV - 10 MeV range.

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team, report:

The short-duration, extremely bright GRB 181222B (Veres, GCN 23551
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 )
was detected by Fermi (GBM trigger 567202302) and Konus-Wind
at about 72697 s UT (20:11:37).

We have triangulated it to a Konus-GBM annulus centered at 
RA(2000)=294.324 deg (19h 37m 18s) Dec(2000)=-23.694 deg (-23d 41' 39"), 
whose radius is 51.089 +/- 0.097 deg (3 sigma). The annulus reduces the 
area of the 3 sigma Fermi-GBM final position by about a factor of 130.

This annulus may be improved.

A triangulation map is posted at
ttp://www.ioffe.ru/LEA/GRBs/GRB181222_T72694/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.

V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina,  P.Balanutsa, A.Kuznetsov, V.Vladimirov, D. Vlasenko
Lomonosov Moscow State University, SAI, Physics Department

D. Buckley, 
South African Astronomical Observatory

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

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

O. Gres, N.M. Budnev, O.Ershova, Yu.Ishmuhametov
Applied Physics Institute, Irkutsk State University

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

R. Podesta, Carlos Lopez, F. Podesta, C.Francile
Observatorio Astronomico Felix Aguilar (OAFA)

H. Levato 
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)


MASTER-IAC robotic telescope (4 square degreess,Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to 
the  GRB181222B 107 sec after trigger time 
at 2018-12-22 20:13 24 UT in two polarizations. On our first ( 20s 
exposure )  set we  not found  optical transient within FERMI error-box (ra=311.146 dec=22.8597 r=1.6)

The real time  cover map is available
https://master.sai.msu.ru/site/master2/event.php??not=2018-12-22%2020:20:57&sat=FERMI&gcrd=(311.146d,22.8597d)&eb=1.6&trig=2018-12-22%2020:11:37&n=GRB181222.84


====================================================================

The galactic latitude b = -13 deg., longitude l = 67 deg.
The observations made on zenit distance = 62 deg.The moon (100 % bright 
part) is 25 deg. above the horizon. The distance between  moon and  object 
is 122
The sun  altitude  is -27.2 deg.
The object can be observed till sunrise at 2018-12-23 07:52:51


MASTER-Amur robotic telescope (Global MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical 
University) was starting survey on the FERMI  GRB181222B error-box (20 
44 35 dec=+22 51 36, r=1.6)  45931 sec after notice time and 46503 sec 
after trigger time at 2018-12-23 09:06:40 UT. The 5-sigma upper limit on 
our first (60s exposure)  set is about 16.5 mag


The full information about this GRB181222B available here 
https://176.123.192.71//master2/grb.php?not=2018-12-22+20%3A21%3A08.37&sat=FERMI&gcrd=%28311.146d%2C22.86d%29&eb=1.6&trig=2018-12-22+20%3A11%3A37&n=GRB181222.84
The message may be cited.


====================================================================


The galactic latitude b = -13 deg., longitude l = 67 deg.
The observations made on zenit distance = 44 deg.
The moon (99 % bright 
part) is  8 deg. above the horizon. The distance between  moon and  object 
is 127.

  Observations started at twilight.
The sun  altitude  is -14.6 deg.
The object can be observed till 2018-12-23 14:13:01.

The observations and reduction continue.


The message may be cited.

P Veres (UAH) reports on behalf of the Fermi GBM Team:

"At 20:11:37.438 UT on 22 December 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 181222B (trigger 567202302 / 181222841).

The on-ground calculated location, using the GBM trigger
data, is RA = 311.2, DEC = 22.9 (J2000 degrees,
equivalent to 22 h 45 m, 22 d 52 '), with an uncertainty
of 1.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 65
degrees.


The GBM light curve shows a very intense peak
with a duration (T90) of about 0.5 s (50-300 keV).
The time-averaged spectrum from T0  to T0+1.1 s is best fit by
a Band function with Epeak = 380 +/- 8 keV,
alpha = -0.74 +/- 0.01, and beta = -2.98 +/- 0.11

The event fluence (10-1000 keV) in this time interval is
(3.44 +/- 0.03)E-5 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+0.14 s in the 10-1000 keV band
is 800 +/- 6 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."