Gamma-ray Burst 190708B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN Notice

TITLE:           GCN/MAXI NOTICE
NOTICE_DATE:     Mon 08 Jul 19 20:44:55 UT
NOTICE_TYPE:     MAXI Unknown Source Position
EVENT_ID_NUM:    672688062
EVENT_RA:        326.86d {+21h 47m 25s} (J2000),
                 327.10d {+21h 48m 24s} (current),
                 326.24d {+21h 44m 57s} (1950)
EVENT_DEC:        +7.64d {+07d 38' 13"} (J2000),
                  +7.73d {+07d 43' 41"} (current),
                  +7.40d {+07d 24' 17"} (1950)
EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
EVENT_FLUX:      682.0 +- 0.0 [mCrab]
EVENT_DATE:      18672 TJD;   189 DOY;   19/07/08
EVENT_TIME:      71421.00 SOD {19:50:21.00} UT
EVENT_TSCALE:    30s
EVENT_EBAND:     Low, 2-4 keV
SUN_POSTN:       107.79d {+07h 11m 10s}  +22.43d {+22d 25' 43"}
SUN_DIST:        131.10 [deg] 
MOON_POSTN:      190.06d {+12h 40m 15s}   +1.35d {+01d 20' 43"}
MOON_DIST:       136.20 [deg] 
MOON_ILLUM:      43 [%] 
GAL_COORDS:       64.15,-33.51 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      331.84, 19.72 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.

GCN Notice

TITLE:           GCN/MAXI NOTICE
NOTICE_DATE:     Mon 08 Jul 19 20:54:11 UT
NOTICE_TYPE:     MAXI Unknown Source Position
EVENT_ID_NUM:    672688062
EVENT_RA:        326.57d {+21h 46m 17s} (J2000),
                 326.81d {+21h 47m 15s} (current),
                 325.95d {+21h 43m 48s} (1950)
EVENT_DEC:        +7.71d {+07d 42' 40"} (J2000),
                  +7.80d {+07d 48' 06"} (current),
                  +7.48d {+07d 28' 46"} (1950)
EVENT_ERROR:     1.0 [deg radius, stat+sys, 90% containment]
EVENT_FLUX:      394.0 +- 0.0 [mCrab]
EVENT_DATE:      18672 TJD;   189 DOY;   19/07/08
EVENT_TIME:      71421.00 SOD {19:50:21.00} UT
EVENT_TSCALE:    30s
EVENT_EBAND:     Low, 2-4 keV
SUN_POSTN:       107.80d {+07h 11m 12s}  +22.43d {+22d 25' 40"}
SUN_DIST:        131.28 [deg] 
MOON_POSTN:      190.14d {+12h 40m 35s}   +1.31d {+01d 18' 40"}
MOON_DIST:       135.84 [deg] 
MOON_ILLUM:      44 [%] 
GAL_COORDS:       64.01,-33.25 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      331.58, 19.89 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        MAXI Unknown Source Position. GRB or unknown X-ray Transient.

GCN Circular #25037
Y. Kawakubo (LSU), M. Nakajima (Nihon U.), M. Serino (AGU), H. Negoro, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), S. Nakahira, T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, M. Sugizaki, M. Oeda, K. Shiraishi (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai, M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, Y. Kurihara, K. Kurogi, K. Miike (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 19:49:58 UT . Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (326.571 deg, 7.711 deg) = (21 46 17, +07 42 39) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.22 deg and 0.19 deg, respectively. The roll angle of long axis from the north direction is 125.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 394 +- 60 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) = (325.953, 7.630) deg = (21 43 48, +07 37 47) (J2000)
(R.A., Dec) = (326.121, 7.246) deg = (21 44 29, +07 14 45) (J2000)
(R.A., Dec) = (327.396, 7.791) deg = (21 49 35, +07 47 27) (J2000)
(R.A., Dec) = (327.229, 8.175) deg = (21 48 54, +08 10 30) (J2000)
```
There was no significant excess flux in the previous transit at UT 19:29 and in the next transit at 21:02 UT with an upper limit of 20 mCrab for each.
GCN Circular #25039
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the MAXI GRB190708.83 (trigger No 6726888062, 21h 47m 25.42s , + 7d 38m 12.84s, R=1) errorbox 27 sec after notice time and 3305 sec after trigger time at 2019-07-08 20:45:26 UT, with upper limit up to 16.1 mag. The observations began at zenit distance = 77 deg. The sun altitude is -62.1 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the MAXI GRB190708.83 errorbox 563 sec after notice time and 3841 sec after trigger time at 2019-07-08 20:54:22 UT, with upper limit up to 17.2 mag. The observations began at zenit distance = 52 deg. The sun altitude is -24.3 deg.
The galactic latitude b = -60 deg., longitude l = 98 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1069090
We obtain a following upper limits.
```
Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________


    3395 | 2019-07-08 20:45:26 |         MASTER-SAAO | ( 21h 47m 29.32s , + 7d 35m 30.34s) |  P\ |   180 | 13.0 |        
    3575 | 2019-07-08 20:45:26 |         MASTER-SAAO | ( 21h 47m 29.39s , + 7d 35m 30.50s) |  P\ |   540 | 15.7 |  Coadd 
    3606 | 2019-07-08 20:48:56 |         MASTER-SAAO | ( 21h 47m 29.44s , + 7d 35m 37.76s) |  P\ |   180 | 15.3 |        
    3819 | 2019-07-08 20:52:29 |         MASTER-SAAO | ( 21h 47m 29.48s , + 7d 35m 42.19s) |  P\ |   180 | 15.8 |        
    3931 | 2019-07-08 20:54:22 |   MASTER-Kislovodsk | ( 21h 45m 38.94s , + 7d 54m 07.21s) |  P- |   180 | 16.4 |        
    3931 | 2019-07-08 20:54:22 |   MASTER-Kislovodsk | ( 21h 45m 44.57s , + 7d 25m 53.57s) |  P| |   180 | 16.6 |        
    4291 | 2019-07-08 20:54:22 |   MASTER-Kislovodsk | ( 21h 45m 44.57s , + 7d 25m 53.59s) |  P| |   900 | 17.1 |  Coadd 
    4030 | 2019-07-08 20:56:01 |         MASTER-SAAO | ( 21h 47m 29.46s , + 7d 35m 44.99s) |  P\ |   180 | 16.1 |        
    4135 | 2019-07-08 20:57:46 |   MASTER-Kislovodsk | ( 21h 45m 39.08s , + 7d 54m 08.03s) |  P- |   180 | 16.5 |        
    4135 | 2019-07-08 20:57:46 |   MASTER-Kislovodsk | ( 21h 45m 44.71s , + 7d 25m 53.89s) |  P| |   180 | 16.8 |        
    4544 | 2019-07-08 21:04:35 |   MASTER-Kislovodsk | ( 21h 45m 39.07s , + 7d 54m 16.40s) |  P- |   180 | 16.9 |        
    4544 | 2019-07-08 21:04:35 |   MASTER-Kislovodsk | ( 21h 45m 45.10s , + 7d 26m 01.75s) |  P| |   180 | 17.2 |        
```
The observation and reduction will continue. The message may be cited.
GCN Circular #25040
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a series of observations, tiled on the sky, of the MAXI GRB 190708B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00080
Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: 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.
GCN Circular #25043
A. Kozlova, S. Golenetskii, R.Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
A long GRB was detected by Konus-Wind (KW) in the waiting mode on July 8, 2019 at ~71160 s UT (19:46:00), ~240 s before the MAXI trigger (GRB 190708B; Kawakubo et al., GCN 25037).
The burst light curve shows a single pulse with a duration of ~ 20 s. Taking into account the proximity of this burst to the MAXI/GSC trigger and the consistency of the KW ecliptic latitude response with the position of GRB 190708B we suggest that KW observed the main part of GRB 190708B.
As observed by KW, the burst had a fluence of 3.44(-0.33,+1.35)x10^-6 erg/cm2 and a 2.944-s peak flux, measured from ~T0(MAXI)-236.3 s, of 2.54(-0.73,+1.21)x10^-7 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
Modeling the KW 3-channel time-integrated spectrum (from ~T0(MAXI)-242.2 s to ~T0(MAXI)-221.6 s) by a simple power-law model yields the power law index of -2.01(-0.08,+0.16), chi2 = 3.3/1 dof.
Modeling this spectrum by a power law with exponential cutoff model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the photon index alpha fixed to -1, yields Ep = 91.6 (-15.7,+28.7) keV, chi2 = 0.12/1 dof.
The KW light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB190708B
All the quoted errors are estimated at the 1 sigma confidence level. All the presented results are preliminary.
GCN Circular #25053
A. Tohuvavohu (PSU), J.A. Kennea (PSU), B. Sbarufatti (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the MAXI-detected burst GRB 190708B (Kawakubo et al. GCN Circ. 25037) in a series of observations tiled on the sky. The total exposure time is 3.9 ks, distributed over 7 tiles; the maximum exposure at a single sky location was 1.2 ks. The data were collected between T0+58.5 ks and T0+69.2 ks, and are entirely in Photon Counting (PC) mode.
One uncatalogued X-ray source has been detected, it is below the RASS limit and shows no definitive signs of fading. Therefore, at the present time we cannot confirm this as the afterglow. Details of this source are given below:
Source 1:
```
  RA (J2000.0):  326.4868  =  21:45:56.83
  Dec (J2000.0): +7.8821  =  +07:52:55.5
  Error: 7.7 arcsec (radius, 90% conf.)
  Count-rate: 0.0151 [+0.0054, -0.0044] ct s^-1   
  Distance: 685 arcsec from MAXI position.
  Flux: (2.13 [+0.77, -0.62])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV)
```
A catalogued source was also detected.
The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00080.
This circular is an official product of the Swift-XRT team.
GCN Circular #25073
B. Sbarufatti (PSU) reports on behalf of the Swift/XRT team:
Swift has performed further observations of the field of the MAXI/GSC-detected burst GRB 190708B (Kawabuko et al., GCN 25037). An additional 3.4 ks of data were collected between 5.96 days and 6.11 days after the MAXI trigger. Source 1, initially reported by Tohuvavohu et al. (GCN 25053) as the likely X-ray counterpart, has faded to a level of 2.9E-3 counts/s (1.3E-13 ergs/cm^2/s). Source 1 is therefore confirmed as the X-ray afterglow of GRB 190708B.
This circular is an official product of the Swift-XRT team.

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Jochen Greiner, last update: 15-Jul-2019 [Disclaimer]