GRB 190706C

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

and

S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer,
on behalf of the Swift-BAT team, report:

The long-duration, very bright GRB 190706C
has been detected by INTEGRAL (SPI-ACS trigger 8325),
CALET (GBM trigger 1246455687), Konus-Wind, and Swift (BAT),
so far, at about 49348 s UT (13:42:28).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   351.671 (23h 26m 41s) +24.754 (+24d 45' 15")
  Corners:
   352.463 (23h 29m 51s) +23.689 (+23d 41' 22")
   352.742 (23h 30m 58s) +23.905 (+23d 54' 20")
   350.850 (23h 23m 24s) +25.803 (+25d 48' 11")
   350.570 (23h 22m 17s) +25.583 (+25d 35' 00")
  ---------------------------------------------
The error box area is about 3079 sq. arcmin, and its maximum
dimension is 2.59 deg (the minimum one is 20.0 arcmin).
The Sun distance was about 100 deg.

This box may be improved.

This burst is spatially and temporally inconsistent with
LIGO/Virgo S190706ai (LVC GCN Circ. 24998
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 ) and
LIGO/Virgo S190707q (LVC GCN Circ. 25012
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 ).

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190706_T49348/IPN

The time history and spectrum will be given in forthcoming
GCN Circulars.

T. Sakamoto, A. Yoshida, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The bright GRB 190706C (IPN triangulation: Svinkin et al., GCN
Circ. 25035
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 ) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 13:42:22.560 UTC on 6 July 2019.
The burst signal was seen by all CGBM detectors.

The burst light curve shows a single multi-peaked emission episode which
starts at T+3.5 sec, peaks at T+6.6 sec and ends at T+10.4 sec. The T90
and T50 durations measured by the SGM data are 3.9 +- 0.8 sec and
2.2 +- 0.1 sec (40-1000 keV), respectively.

Despite the burst high intensity there is almost no emission above ~1 MeV.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1246455687/

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

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

The long-duration, very bright GRB 190706C
(IPN triangulation: Svinkin et al., GCN 25035
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 ;
CALET Gamma-Ray Burst Monitor detection: Sakamoto et al., GCN 25038
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 )
triggered Konus-Wind at T0=49348.84 s UT (13:42:28.840).

The burst light curve shows a multi-peaked structure
with a total duration of ~6.5 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 2.52(-0.17,+0.20)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+2.640 s,
of 1.80(-0.19,+0.19)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+3.072 s)
is best fit in the 20 keV - 2 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.56(-0.09,+0.10),
the high energy photon index beta = -3.09(-0.70,+0.35),
the peak energy Ep = 281(-20,+19) keV,
chi2 = 34/56 dof.

The spectrum near the peak count rate
(measured from T0+2.048 to T0+3.072 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with�� alpha = -0.39(-0.12,+0.13),
and Ep = 288(-19,+22) keV (chi2 = 53/51 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.86 (chi2 = 52/50 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190706_T49348/

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

Y. G. Zheng, C. Cai, Q. Luo, S. Xiao, Q. B. Yi, 
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team:

At 2019-07-06T13:42:25.95 (T0), Insight-HXMT/HE detected 
GRB 190706C (trigger ID: HEB190706571) in a routine search of the data, 
which was also triggered by INTEGRAL/SPI-ACS (trigger #8325),
CALET/CGBM (GCN #25038
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 ) and Konus-Wind (GCN #25042
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 ).

The Insight-HXMT/HE light curve mainly consists of a multiple  
pulses with a duration (T90) of 2.88 s measured from T0+0.13 s. 
The 1-ms peak rate, measured from T0+2.76 s, is 25839 cnts/sec. 
The total counts from this burst is 32484 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB190706571_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information about it could be found at: 
http://www.hxmt.org.