GRB 190928A

A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M.
Cardillo, C. Casentini, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori, F.
Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, N. Parmiggiani
(INAF/OAS-Bologna), M. Pilia (INAF/OA-Cagliari), F. Longo (Univ. Trieste
and INFN Trieste), report on behalf of the AGILE Team:

AGILE detected a long burst at T0 = 2019-09-28 13:13:48.39 +/- 0.01 s
(UTC). The event is visible in the scientific ratemeters (RMs) of the
Super-AGILE (SA; 18-60 keV), Anti-Coincidence (AC; 50-200 keV), and
Mini-CALorimeter (MCAL; 0.4-100 MeV) detectors. Their light curves show a
multi-peaked profile, lasting ~20 s and releasing ~2,200 counts in the SA
RMs, lasting ~30 s and releasing ~160,000 counts in the AC RMs, and lasting
~20 s and releasing ~73,200 counts in the MCAL RMs. The ratemeters light
curves can be found at
http://www.agilescienceapp.it/notices/GRB_064516_496761236.785171_RM.png.

The event also triggered two Mini-Calorimeter (MCAL) data acquisitions (in
the 0.4-100 MeV energy range). Additional analysis of the AGILE data is in
progress.

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, A. Kozyrev, 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, very bright GRB 190928A
was detected by AGILE (Ursi et al., GCN Circ. 25859
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 ),
CALET (GBM trigger 1253711524), Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND) at about 47536 s UT (13:12:16).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    36.579 (02h 26m 19s) +29.461 (+29d 27' 38")
  Corners:
    31.573 (02h 06m 17s) +35.236 (+35d 14' 10")
    40.668 (02h 42m 40s) +23.151 (+23d 09' 02")
    42.081 (02h 48m 19s) +19.298 (+19d 17' 54")
    32.689 (02h 10m 45s) +33.718 (+33d 43' 03")
  ---------------------------------------------
The error box area is about 4.56 sq. deg, and its maximum
dimension is 18.4 deg (the minimum one is 17.6 arcmin).
The Sun distance was about 139 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190928_T47536/IPN

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

V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, 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 long bright GRB 190928A (AGILE/MCAL detection: Ursi et al., GCN Circ.
25859
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 ; IPN triangulation: Hurley et al., GCN Circ. 25864
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 ) triggered the
CALET Gamma-ray Burst Monitor (CGBM) at 13:12:11.187 UTC on 28 September
2019. The burst signal was seen by all CGBM detectors.

The burst light curve shows two multi-peaked pulses separated by a period
of low-level emission. The first pulse starts at T+2.6 sec, peaks at
T+4.8 sec and ends at T+8.1 sec, the second, much brighter, pulse starts at
T+76.4 sec, peaks at T+106.1 sec and ends at T+175.5 sec.
The T90 and T50 durations measured by the SGM data are 106.6 +- 49.1 sec and
6.9 +- 0.4 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1253711524/

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, N.Tiurina, F.Balakin, P.Balanutsa,A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov,
D.Zimnukhov,V.Senik, T.Pogrosheva, K.Pozdnyakov, A.Chasovnikov, V.Topolev, D.Kuvshinov(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 inspect of long/bright (Hurley et al. IPN triangulation GCN 25864
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 )
GRB 190928A (Ursi  et al. AGILE GCN 25859
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  , GCN 25865
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 )

MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory)
  started inspect of the IPN GRB190928.55/GRB190928A errorbox  43353 sec after trigger time at 2019-09-29 01:14:49 UT,
with upper limit up to  19.8 mag.
The observations began at zenit distance = 54 deg. The sun  altitude is -38.1 deg.

MASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) 
started inspect of the IPN GRB190928.55 errorbox  50163 sec after trigger time at 2019-09-29 03:08:19 UT,
with upper limit up to  20.1 mag.
  The observations began at zenit distance =  4 deg. The sun  altitude  is -48.7 deg.

MASTER-Amur robotic telescope  located in Russia (Blagoveshchensk State Pedagogical University)
started inspect of the IPN GRB190928.55 errorbox  77575 sec after trigger time at 2019-09-29 10:45:11 UT,
with upper limit up to  17.2 mag.
Observations started at twilight.  The observations began at zenit distance = 67 deg. The sun  altitude  was -15.1 deg.

MASTER-Tunka robotic telescope  located in Russia (Applied Physics Institute, Irkutsk State University)
started inspect of the IPN GRB190928.55 errorbox  83489 sec after trigger time at 2019-09-29 12:23:45UT,
with upper limit up to  20.0 mag. Observations started at twilight. 
The observations began at zenit distance = 67 deg. The sun  altitude  is -15.2 deg.

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory)
started inspect of the IPN GRB190928.55 errorbox  1 days 18913 sec after trigger time at 2019-09-29 18:27:29 UT,
with upper limit up to  20.4 mag.
The observations began at zenit distance = 63 deg. The sun  altitude  is -36.9 deg.

The error-box center galactic latitude b = -60 deg., longitude l = 98 deg.

We obtained following upper limits.

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
    43444 | 2019-09-29 01:14:49 |         MASTER-SAAO | (02h 47m 41.951s , +22d 01m 46.67s) |   C |   180 | 17.2 |
    43662 | 2019-09-29 01:18:27 |         MASTER-SAAO | (02h 32m 39.043s , +24d 01m 24.20s) |   C |   180 | 14.7 |
    50253 | 2019-09-29 03:08:19 |          MASTER-IAC | (02h 31m 38.751s , +23d 59m 41.60s) |   C |   180 | 19.9 |
    50254 | 2019-09-29 03:08:19 |          MASTER-IAC | (02h 40m 38.749s , +23d 55m 43.19s) |   C |   180 | 20.1 |
    51547 | 2019-09-29 03:29:52 |          MASTER-IAC | (02h 31m 36.457s , +23d 59m 19.80s) |   C |   180 | 19.9 |
    51547 | 2019-09-29 03:29:52 |          MASTER-IAC | (02h 40m 36.860s , +23d 55m 26.72s) |   C |   180 | 20.1 |
    51803 | 2019-09-29 03:34:09 |          MASTER-IAC | (02h 38m 14.592s , +21d 54m 59.78s) |   C |   180 | 20.0 |
    52057 | 2019-09-29 03:38:22 |          MASTER-IAC | (02h 46m 38.495s , +21d 59m 15.57s) |   C |   180 | 20.0 |

MASTER real time updated cover map of GRB190928A  and our upper limits are available at
https://master.sai.msu.ru/site/master2/ligo_1.php?id=10845

MASTER OT J020953.61+360533.8 discovery

During inspect, MASTER-Kislovodsk auto-detection system discovered OT source at
(RA, Dec) = 02h 09m 53.61s +36d 05m 33.8s on 2019-09-29.86025UT.

The OT unfiltered magnitude is 18.4m (mlimit 19.9m).
The OT is seen in 2 images. There is no minor planet at this place.

We have reference images without OT on 2014-10-28.91229 UT with unfiltered 
magnitude limit 20.6m, nearest in time on 2019-06-19 23:25:49 with mlim=18.2 (MASTER-Kislovodsk).

Our preliminary classification is CV, but 
Spectral observations are required.

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/020953.61360533.8.png

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

The long, very bright GRB 190928A
(AGILE/MCAL detection: Ursi et al., GCN 25859
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 ;
IPN triangulation: Hurley et al., GCN 25864
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 ;
CALET Gamma-Ray Burst Monitor detection: Pal'shin et al., GCN 25865
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 )
triggered Konus-Wind (KW) at T0=47536.665 s UT (13:12:16.665).

The burst light curve starts with a smooth pulse, which was followed,
after a period of low-level emission, by a much more intense,
multi-peaked emission complex. The total duration of the burst is ~195 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/GRB190928_T47536/

As observed by Konus-Wind, the burst had
a fluence of (4.9 �� 0.3)x10^-4 erg/cm^2 and
a 256-ms peak energy flux, measured from T0+103.168,
of (9.0 �� 0.2)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+185.334 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.98 (-0.07,+0.07),
the high energy photon index beta = -1.97 (-0.13,+0.07),
the peak energy Ep = 591 (-88,+108) keV,
chi2 = 89/97 dof.

The spectrum near the peak count rate (measured from T0+103.168 s
to T0+103.424 s) is best fit in the 20 keV - 20 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.72 (-0.25,+0.26),
the high energy photon index beta = -1.73 (-0.24,+0.09),
the peak energy Ep = 636 (-232,+754) keV,
chi2 = 72/57 dof.

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.

Q. Luo, C. Cai, S. Xiao, Q. B. Yi, Y. G. Zheng, Y. Huang, 
C. K. Li, X. B. Li, G. 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 2019-09-28T13:12:14.00 (T0), Insight-HXMT/HE detected 
GRB 190928A (trigger ID: HEB190928550) in a routine search of the data, 
which was also reported by AGILE/MCAL (GCN #25859
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 ), IPN triangulation 
(GCN #25864
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 ), CALET/GBM (GCN #25865
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 ) and Konus-Wind (GCN #25868
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 ). 

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 31.10 s measured from T0+78.39 s. 
The 1-ms peak rate, measured from T0+102.88 s, is 23712 cnts/sec. 
The total counts from this burst is 152469 counts. The data of 
Insight-HXMT/HE suffers saturation in the brightest part.
URL_LC: http://www.hxmt.org/images/GRB/HEB190928550_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.

R. Gaikwad, 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 the detection of a GRB 190928A, which was also detected by AGILE/MCAL (Ursi A. et al., GCN # 25859), IPN Triangulation (Hurley K. et al., GCN # 25864), CALET Gamma-ray Burst Monitor (Valentin P. et al., GCN # 25865), MASTER optical observations (Lipunov L. et al., GCN # 25867), Konus-Wind observation (Frederiks D. et al., GCN # 25868) and Insight-HXMT/HE (Luo Q. et al., GCN # 25879).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with the strongest peak at 2019-09-28 13:12:16.0 UT. The measured peak count rate associated with the burst is 3601 cts/s above the background in the combined data of four quadrants, with a total of 52582 cts. The local mean background count rate was 494 cts/s. Using cumulative rates, we measure a T90 of 114.6 s. In preliminary analysis, we find that 4621 Compton events are associated with this event.

It was also clearly 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.