GRB 190805B
GCN Circular 25316
Subject
IPN triangulation of GRB 190805B
Date
2019-08-13T08:09:10Z (6 years ago)
From
Anna Kozlova at Ioffe Institute <ann_kozlova@mail.ioffe.ru>
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,
A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM 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 190805B
(MAXI/GSC detection: Sato et al., GCN Circ. 25271;
Fermi/GBM detection: Hamburg & Meegan, GCN Circ. 25277)
was detected by Fermi (GBM trigger 586673165), INTEGRAL (SPI-ACS),
Mars-Odyssey (HEND), Konus-Wind and MAXI (GSC) at about 17159 s UT
(04:45:59).
We have triangulated it to a Konus-HEND annulus centered at
RA(2000)=321.552 deg (21h 26m 13s) Dec(2000)=-16.302 deg (-16d 18'
08"),
whose radius is 61.012 +/- 0.062 deg (3 sigma).
Only a rectangular error box of the MAXI/GSC position reported
by Sato et al. (GCN Circ. 25271) is consistent with the annulus.
The annulus combined with the MAXI (90 % containment, statistical-only)
localization gives the following error box:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
212.376 (14h 09m 30s) +19.776 (+19d 46' 32")
Corners:
212.356 (14h 09m 25s) +20.078 (+20d 04' 39")
212.487 (14h 09m 57s) +20.071 (+20d 04' 15")
212.395 (14h 09m 35s) +19.474 (+19d 28' 25")
212.265 (14h 09m 03s) +19.480 (+19d 28' 49")
---------------------------------------------
The error box area is 267 sq. arcmin (a factor of 16
smaller than that of the MAXI error box), and its maximum
dimension is 38 arcmin (the minimum one is 7 arcmin).
The Sun distance was ~73 deg.
The box is partially covered with the Swift XRT observations
reported by Perri et al. (GCN Circ. 25279).
This box may be improved.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190805_T17159/IPN/
GCN Circular 25287
Subject
GRB 190805B: AstroSat CZTI detection
Date
2019-08-08T11:27:52Z (6 years ago)
From
Prachee Ghumatkar at IUCAA/AstroSat <prachee@iucaa.in>
P. Ghumatkar, V. Sharma and D. Bhattacharya and A. Vibhute (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 long GRB 190805B, which was also detected by Fermi GBM Final Real-time Localization (GCN #25270), MAXI/GSC detection (Sato T. et al., GCN #25271), BALROG localization (Biltzinger B. et al., GCN #25272), Tiled Swift observations (Evans P. A. et al., GCN #25275), Fermi GBM detection (Hamburg R. et al., GCN #25277), Swift-XRT (Perri M. et al., GCN #25279) and Konus-Wind (Kozlova A. et al., GCN #25285).
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 04:46:05.0 UT. The measured peak count rate associated with the burst is 323 cts/s above the background in the combined data of four quadrants, with a total of 4289 cts. The local mean background count rate was 588 cts/s. Using cumulative rates, we measure a T90 of 24 s.
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.
GCN Circular 25285
Subject
Konus-Wind observation of GRB 190805B
Date
2019-08-08T05:42:10Z (6 years ago)
From
Anna Kozlova at Ioffe Institute <ann_kozlova@mail.ioffe.ru>
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:
The long-duration GRB 190805B
(MAXI/GSC detection: Sato et al., GCN Circ. 25271;
Fermi/GBM detection: Hamburg & Meegan, GCN Circ. 25277)
triggered Konus-Wind at T0=17159.354 s UT (04:45:59.354).
The burst light curve shows a multipeaked structure
which starts at ~T0-6.1 s and has a total duration of ~27.9 s.
The emission is seen up to ~6 MeV.
As observed by Konus-Wind, the burst
had a fluence of 1.46(-0.16,+0.24)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+14.832 s,
of 4.76(-1.60,+8.56)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+24.832 s)
is best fit in the 20 keV - 6 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.07(-0.23,+0.26)
and Ep = 315(-73,+148) keV (chi2 = 66/79 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.0
(chi2 = 65/78 dof).
The spectrum near the maximum count rate
(measured from T0+8.448 to T0+16.640 s)
is best fit in the 20 keV - 6 MeV range
by a power law with exponential cutoff model
with alpha = -1.28(-0.44,+0.55)
and Ep = 281(-118,-281) keV (chi2 = 45/78 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.7
(chi2 = 44/77 dof).
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190805_T17159/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 25279
Subject
GRB 190805B: Swift-XRT observations
Date
2019-08-06T05:24:47Z (6 years ago)
From
Kim Page at U.of Leicester <klp5@leicester.ac.uk>
M. Perri (ASDC), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea
(PSU), B. Sbarufatti (PSU), D.N. Burrows (PSU), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester) 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 190805B (Sato et al. GCN Circ. 25271) in a series of
observations tiled on the sky. The total exposure time is 1.3 ks,
distributed over 7 tiles; the maximum exposure at a single sky location
was 391 s. The data were collected between T0+47.6 ks and T0+49.0 ks,
and are entirely in Photon Counting (PC) mode.
No X-ray sources have been detected. The 3-sigma upper limit in the
field (not including the regions where the tiles overlap) ranges from
~0.03 to ~0.11 ct s^-1, corresponding to a 0.3-10 keV observed flux of
1.2e-12 to 4.4e-12 erg cm^-2 s^-1 (assuming a typical GRB spectrum).
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_GRB00083.
This circular is an official product of the Swift-XRT team.
GCN Circular 25277
Subject
GRB 190805B: Fermi GBM detection
Date
2019-08-05T21:16:24Z (6 years ago)
From
Rachel Hamburg at UAH <rkh0007@uah.edu>
R. Hamburg (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 04:46:00.97 UT on 05 August 2019, the Fermi Gamma-Ray Burst Monitor
(GBM)
triggered and located GRB 190805B (trigger 586673165 / 190805199),
which was also detected by the MAXI/GSC (Sato et al. 2019, GCN 25271).
The Fermi GBM Final Real-time Localization (GCN 25270) is consistent with
the MAXI position.
The angle from the Fermi LAT boresight at the GBM trigger time is 46
degrees.
The GBM light curve shows a spiky, multi-peaked structure with a
duration (T90) of about 22 s (50-300 keV). The time-averaged
spectrum from T0-4.6 s to T0+ 25.1 s is best fit by a power law function
with an exponential high-energy cutoff. The power law index
is -1.07 +/- 0.05 and the cutoff energy, parameterized as Epeak,
is 389 +/- 51 keV.
The event fluence (10-1000 keV) in this time interval is
(1.03 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+16 s in the 10-1000 keV band
is 7.6 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support
Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular 25275
Subject
GRB 190805B: Tiled Swift observations
Date
2019-08-05T18:09:15Z (6 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
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 190805B. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00083
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 25272
Subject
GRB 190805B: BALROG localization (Fermi Trigger 586673165 / GRB 190805199)
Date
2019-08-05T07:50:20Z (6 years ago)
From
Jochen Greiner at MPE,Garching <jcg@mpe.mpg.de>
B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
586673165 at 04:46:00 on 05 Aug. 2019 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 207.8+/-2.2 deg
Decl.(2000.0) = 19.4+/-2.0 deg
We estimate an additional systematic error of 2 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190805199/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190805199/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190805199/json
GCN Circular 25271
Subject
GRB 190805B: MAXI/GSC detection
Date
2019-08-05T05:32:21Z (6 years ago)
From
Hitoshi Negoro at Nihon U <negoro@cygnus.phys.cst.nihon-u.ac.jp>
T. Sato (Chuo U.), H. Negoro, M. Nakajima, W. Maruyama, M. Aoki,
K. Kobayashi (Nihon U.), T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, M. Serino, S. Sugita, H. Nishida, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai (Chuo U.), M. Shidatsu (Ehime U.),
N. Kawai, M. Sugizaki, M. Oeda, K. Shiraishi (Tokyo Tech), S. Nakahira, Y. Sugawara,
S. Ueno, H. Tomida, M. Ishikawa, 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.), Y. Kawakubo (LSU)
report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered on an uncatalogued X-ray transient source
at 04:49:12 UT on 2019 August 05.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (211.853 deg, 19.766 deg) = (14 07 24, +19 45 57) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.30 deg and 0.29 deg, respectively.
The roll angle of the long axis from the north direction is 170.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 109 +- 18 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) = (210.974, 20.151) deg = (14 03 53, +20 09 03) (J2000)
(R.A., Dec) = (210.941, 19.551) deg = (14 03 45, +19 33 03) (J2000)
(R.A., Dec) = (212.931, 19.442) deg = (14 11 43, +19 26 31) (J2000)
(R.A., Dec) = (212.971, 20.042) deg = (14 11 53, +20 02 31) (J2000)
There was no significant excess flux in the previous transit at 03:16 UT
with an upper limit of 20 mCrab.
This burst is likely the same one that Fermi detected about 3 min earlier
(Trigger number 586673165).
GCN Circular 25270
Subject
GRB 190805B: Fermi GBM Final Real-time Localization
Date
2019-08-05T04:56:51Z (6 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 04:46:00 UT on 5 Aug 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190805B (trigger 586673165.970428 / 190805199).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 209.8, Dec = 19.5 (J2000 degrees, equivalent to J2000 13h 59m, 19d 30'), with a statistical uncertainty of 2.6 degrees.
The angle from the Fermi LAT boresight is 46.0 degrees.
The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190805199/quicklook/glg_skymap_all_bn190805199.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190805199/quicklook/glg_healpix_all_bn190805199.fit
The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190805199/quicklook/glg_lc_medres34_bn190805199.gif