GRB 200412A
GCN Circular 27588
Subject
GRB 200412A : AstroSat CZTI detection
Date
2020-04-15T20:59:14Z (6 years ago)
From
Soumya Gupta at IUCAA/ASTROSAT <soumya@iucaa>
S. Gupta, 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 long GRB 200412A, which was also detected by BALROG (Kunzweiler F. et al., GCN #27546) , Fermi GBM (Mailyan B. et al., GCN #27550), Global MASTER-Net (Lipunov V. et al., GCN #27559), IPN (Hurley K. et al., GCN #27560) and Konus-Wind (Ridnaia A. et al., GCN #27577).
The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 2020-04-12 06:57:14.500 UT. The measured peak count rate associated with the burst is 2671 +/- 57 cts/s above the background in the combined data of four quadrants, with a total of 12092 +/- 16 cts. The local mean background count rate was 487 +/- 0.8 cts/s. Using cumulative rates, we measure a T90 of 12.5 +/- 0.002 s. In preliminary analysis, we find that 959 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.
GCN Circular 27577
Subject
Konus-Wind observation of GRB 200412A
Date
2020-04-14T15:38:35Z (6 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A. Ridnaia, 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 200412A
(BALROG localization: Kunzweiler et al., GCN Circ. 27546;
Fermi-GBM detection: Mailyan and Hamburg., GCN Circ. 27550;
IPN triangulation: Hurley et al., GCN Circ. 27560)
triggered Konus-Wind at T0=25034.8 s UT (06:57:14.800).
The burst light curve shows a multipeaked structure
which starts at ~T0-0.2 s and has a total duration of ~13.3 s.
The emission is seen up to ~4 MeV.
As observed by Konus-Wind, the burst
had a fluence of 3.27(-0.32,+0.35)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+3.792 s,
of 1.18(-0.15,+0.15)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+13.056 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.59(-0.11,+0.12),
the high energy photon index beta = -2.68(-0.41,+0.23),
the peak energy Ep = 229(-19,+20) keV
(chi2 = 56/68 dof).
The spectrum near the maximum count rate
(measured from T0+0.256 to T0+4.864 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.69(-0.08,+0.09)
and Ep = 275(-16,+18) keV (chi2 = 47/68 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.8
(chi2 = 46/67 dof).
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200412_T25034/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 27560
Subject
IPN triangulation of GRB 200412A
Date
2020-04-12T21:20:47Z (6 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
K. Hurley, on behalf of the IPN,
I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak,
and A. B. Sanin, on behalf of the HEND-Odyssey GRB team,
A. Ridnaia, 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 200412A
(BALROG localization: Kunzweiler et al., GCN Circ. 27546;
Fermi-GBM detection: Mailyan & Hamburg, GCN Circ. 27550)
was detected by Fermi (GBM trigger 608367436), Konus-Wind,
INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND)
at about 25032 s UT (06:57:12).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
137.164 (09h 08m 39s) -39.022 (-39d 01' 20")
Corners:
136.598 (09h 06m 24s) -38.953 (-38d 57' 12")
136.795 (09h 07m 11s) -39.172 (-39d 10' 21")
137.730 (09h 10m 55s) -39.086 (-39d 05' 11")
137.530 (09h 10m 07s) -38.870 (-38d 52' 11")
---------------------------------------------
The error box area is 616 sq. arcmin, and its maximum
dimension is 53 arcmin (the minimum one is 14 arcmin).
The Sun distance was 115 deg.
This box may be improved.
The localization is consistent with, but reduces
the area of, the final Fermi-GBM (GCN Circ. 27546) and
BALROG (GCN Circ. 27550) localizations.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB200412_T25034/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.
GCN Circular 27559
Subject
Fermi GRB 200412A: Global MASTER-Net observations report
Date
2020-04-12T19:30:09Z (6 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
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, D. Cheryasov
(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 Fermi GRB 200412A ( B. Mailyan et al., GCN 27550) errorbox 36730 sec after notice time and 36757 sec after trigger time at 2020-04-12 17:09:48 UT, with upper limit up to 19.6 mag. Observations started at twilight. The observations began at zenith distance = 18 deg. The sun altitude is -11.1 deg.
The galactic latitude b = 1 deg., longitude l = 261 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1334799
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
36787 | 2020-04-12 17:09:48 | MASTER-SAAO | (09h 13m 52.34s , -41d 51m 51.9s) | C | 60 | 18.4 |
37119 | 2020-04-12 17:15:21 | MASTER-SAAO | (09h 13m 54.79s , -41d 51m 51.5s) | C | 60 | 18.8 |
38182 | 2020-04-12 17:33:03 | MASTER-SAAO | (09h 10m 06.68s , -43d 53m 01.7s) | C | 60 | 19.5 |
38513 | 2020-04-12 17:38:34 | MASTER-SAAO | (09h 10m 03.48s , -43d 53m 49.3s) | C | 60 | 19.5 |
38840 | 2020-04-12 17:44:01 | MASTER-SAAO | (09h 06m 39.51s , -39d 52m 36.7s) | C | 60 | 19.5 |
38843 | 2020-04-12 17:44:04 | MASTER-SAAO | (08h 57m 23.15s , -39d 53m 40.6s) | C | 60 | 19.6 |
38922 | 2020-04-12 17:45:24 | MASTER-SAAO | (09h 02m 33.15s , -37d 54m 37.1s) | C | 60 | 19.1 |
39169 | 2020-04-12 17:49:31 | MASTER-SAAO | (09h 06m 35.97s , -39d 53m 37.7s) | C | 60 | 19.5 |
39172 | 2020-04-12 17:49:34 | MASTER-SAAO | (08h 57m 19.39s , -39d 54m 42.5s) | C | 60 | 19.6 |
39252 | 2020-04-12 17:50:54 | MASTER-SAAO | (09h 02m 39.08s , -37d 53m 08.5s) | C | 60 | 19.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 27550
Subject
GRB 200412A: Fermi GBM detection
Date
2020-04-12T14:04:54Z (6 years ago)
From
Rachel Hamburg at UAH <rkh0007@uah.edu>
B. Mailyan (Institute for Basic Science, South Korea) and R. Hamburg (UAH)
report on behalf of the Fermi GBM Team:
"At 06:57:11.95 UT on 12 April 2020, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB 200412A (trigger 608367436 / 200412290).
This trigger was originally misclassified as a particle event by the flight
software.
The on-ground calculated location, using the Fermi GBM trigger data, is RA
= 140.01, Dec = -41.67 (J2000 degrees, equivalent to J2000 09h 20m, -41d
40���), with a statistical uncertainty of 1.4 degrees.
The angle from the Fermi LAT boresight is 108 degrees.
The GBM light curve shows multiple short peaks with a duration (T90) of
about 12.6 s (50-300 keV).
The time-averaged spectrum from T0 s to T0+14.0 s is best fit by a Band
function with Epeak = 255 +/- 8.5 keV, alpha = -0.64 +/- 0.03, and beta =
-2.66 +/- 0.14.
The event fluence (10-1000 keV) in this time interval is (3.1 +/- 0.04)E-05
erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.2 s in the
10-1000 keV band is 34.3 +/- 0.6 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 27546
Subject
GRB 200412A: BALROG localization (Fermi Trigger 608367436 / GRB 200412290)
Date
2020-04-12T07:23:34Z (6 years ago)
From
Jochen Greiner at MPE,Garching <jcg@mpe.mpg.de>
F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
608367436 at 06:57:11 on 12 April 2020 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) = 134.2+/-0.8 deg
Decl.(2000.0) = -38.2+/-1.1 deg
We estimate an additional systematic error of 2 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB200412290/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB200412290/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB200412290/json