GRB 181011A

Y. Kawakubo (AGU), M. Nakajima, H. Negoro (Nihon U.), M. Serino (AGU), 
S. Nakahira (RIKEN), A. Sakamaki, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.),  
T. Mihara, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, 
T. Hashimoto, A. Yoshida (AGU), N. Kawai, M. Sugizaki, Y. Tachibana, 
K. Morita (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, 
R. Shimomukai, T. Midooka (JAXA), Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, 
S. Ogawa (Kyoto U.), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, 
T. Sato (Chuo U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), 
M. Yamauchi, K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), 
K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray 
transient source at 2018-10-11T03:36:12 UT.
Assuming that the source flux was constant over the transit, we obtain 
the source position at

(R.A., Dec) = (93.500 deg, 20.837 deg) = (06 14 00, +20 50 13) (J2000) 

with a statistical 90% C.L. elliptical error region with long and short 
radii of 0.26 deg and 0.18 deg, respectively. The roll angle of the long axis 
from the north direction is 101.0 deg counterclockwise. There is an additional 
systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 167 +- 28 mCrab
(4.0-10.0keV, 1 sigma error).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:

(R.A., Dec) = (94.338, 21.465) deg = (06 17 21, +21 27 53) (J2000)
(R.A., Dec) = (93.931, 21.742) deg = (06 15 43, +21 44 31) (J2000)
(R.A., Dec) = (92.419, 19.784) deg = (06 09 40, +19 47 02) (J2000)
(R.A., Dec) = (92.824, 19.511) deg = (06 11 17, +19 30 39) (J2000)

There was no significant excess flux in the next transit at 03:55 UT with 
an upper limit of 20 mCrab.

We note that this burst was detected just after the ISS maneuver, and 
the data arrived at JAXA/TKSC about about 8 hr late. 
This and the confirmation of the event result in the late notice of this burst.

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:

The long-duration GRB 181011A
(MAXI/GSC detection: Kawakubo et al., GCN Circ. 23327
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was detected by Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND) at about 12979 s UT (03:36:19).

We have triangulated it to a preliminary error box
whose coordinates are:
---------------------------------
   RA(2000), deg   Dec(2000), deg
---------------------------------
   Center:
     93.1530       19.1552
   Corners:
     93.2025       23.5555
     94.8930       14.2497
     94.7356       11.0039
     91.9740       23.5347
--------------------------------
The error box area is about 10 sq. deg, and its maximum
dimension is 11.2 deg (the minimum one is 1.1 deg).
The Sun distance was about 171 deg.

This box may be improved.

The box is consistent with the MAXI/GSC localization.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB181011_T12979/IPN/

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

P. S. Marrocchesi (U of Siena), A. Yoshida, T. Sakamoto,
V. Pal'shin, S. Sugita, Y. Kawakubo, A. Tezuka, S. Matsukawa,
H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), A. V. Penacchioni
and the CALET collaboration:

The MAXI GRB 181011A (Kawakubo et al., GCN Circ. 23327
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 ) was detected
in ground analysis of the CALET Gamma-ray Burst Monitor (CGBM) data
near the MAXI trigger time at T0=03:36:12 UT on 11 October 2018.
The burst signal was seen by all CGBM detectors.

The burst light curve shows a single multi-peaked emission episode which 
starts at T+21 sec and ends at T+55 sec.
The T90 and the T50 durations measured by the SGM data are
31 +- 8 sec and 15 +- 8 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1223264170/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.

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

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

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

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

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

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

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

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


MASTER-Kislovodsk robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station 
of Pulkovo observatory) was starting survey on the IPN  GRB181011.15 
error-box (K. Hurley et al GCN 23328
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 )  33218 sec after notice time and 
61888 sec after trigger time at 2018-10-11 20:47:47 UT. The 5-sigma upper 
limit on our images is about 19 mag.


MASTER-Tavrida robotic telescope  located in 
Russia (Lomonosov MSU, SAI Crimea astronomical station) was starting 
survey on the IPN  GRB181011.15 error-box  45716 sec after notice time and 
74386 sec after trigger time at 2018-10-12 00:16:05 UT. The 5-sigma upper 
limit on our images is about 19 mag.

MASTER-Net cover full IPN (K. Hurley et al. GCN 23328
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 ) and MAXI (Kawakubo 
et al. GCN 23327
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 )  error boxes.

Coverage map is available here:
http://master.sai.msu.ru/static//IPN/db/GRB181011.15/img/ligo_master_2018-10-12-05-03-00.eb.zoom.1.pngmlimit.png

R. Adachi, R. Itoh, K. L. Murata, Y. Tachibana, K. Morita,
K. Shiraishi, K. Iida, M. Oeda, M. Niwano,
Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We performed tiling observation for error region of GRB 181011A
(Kawakubo et al., GCN Circular #23327
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with the optical three color (g', Rc, and Ic) CCD cameras attached to
the two MITSuME 50cm telescopes at  Akeno Observatory
and Okayama Astrophysical Observatory, in Japan.

The observation started on 2018-10-12 13:51:34 UT.
Our tiling observation covers about 90% of MAXI error region.
We did not find any point source at the position of the
MAXI error box (Kawakubo et al., GCN Circular #23327
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in all three bands.
Unfortunately, thin cloud were passing during the observation therefore
we could not obtain uniform exposure for each data set between tiling.
Finally we obtained following 5-sigma upper limits for the magnitudes

35% region: g' > 18.0, Rc > 17.7, Ic > 17.0
40% region: g' > 16.5, Rc > 16.2, Ic > 15.7
15% region: g' > 15.0, Rc > 14.7, Ic > 14.2

We used UCAC-4 catalog for flux calibration.