TITLE: GCN CIRCULAR
NUMBER: 34586
SUBJECT: GRB 230826A: VZLUSAT-2 detection
DATE: 23/08/28 17:41:47 GMT
FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz>
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration.
The long duration GRB 230826A (Fermi/GBM detection: GCN 34564; Swift/BAT detection: GCN 34565; GRBAlpha detection: GCN 34572) was detected by the GRB detectors on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).
The data acquisition was performed by the GRB detector units no. 0 and no. 1. The detection was confirmed at the peak time 2023-08-26 19:32:48 UTC. The T90 duration is 17 s (18 s) and the significance during T90 reaches 11 sigma (17 sigma) for detector unit no. 0 (no. 1).
The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB230826A_GCN_VZLUSAT2.pdf
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/
The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.
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TITLE: GCN CIRCULAR
NUMBER: 34585
SUBJECT: GRB 230827B: VZLUSAT-2 detection
DATE: 23/08/28 17:13:25 GMT
FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz>
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration.
The long duration GRB 230827B (Fermi/GBM detection: GCN 34584; GECAM-B detection: trigger no. 215; CALET/CGBM detection: trigger no. 1377151581; INTEGRAL/SPI-ACS detection at 2023-08-27 ~06:08:31 UT) was detected by the GRB detectors on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).
The data acquisition was performed by the GRB detector units no. 0 and no. 1. The detection was confirmed at the peak time 2023-08-27 06:08:33 UTC. The T90 duration is 21 s (17 s) and the significance during T90 reaches 10.2 sigma (7.3 sigma) for detector unit no. 0 (no. 1).
The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB230827B_GCN_VZLUSAT2.pdf
All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/
The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.
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TITLE: GCN CIRCULAR
NUMBER: 34584
SUBJECT: GRB 230827B / GRB 230827256: Fermi GBM Observation
DATE: 23/08/28 13:52:48 GMT
FROM: rachel.hamburg(a)ijclab.in2p3.fr
R. Hamburg (CNRS/IJCLab) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 06:08:30.73 UT on 27 August 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230827B (trigger 714809315/230827256).
The optical afterglow of GRB 230827B was also detected by ZTF (GCN 34574),
GIT (GCN 34576), and AKO (GCN 34579). The location of the afterglow is
consistent with the GBM on-ground calculated location, which is
RA = 299.32, Dec = +56.47 (J2000 degrees, equivalent to
J2000 19h 57m 17s, +56d 28' 12"), with a statistical
uncertainty of 2.17 degrees.
The angle from the Fermi LAT boresight is 140 degrees.
The GBM light curve shows a multi-peaked lightcurve with a duration (T90)
of about 11 s (50-300 keV). The time-averaged spectrum
from T0+0.002 to T0+10.240 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.37 +/- 0.05 and the cutoff energy,
parameterized as Epeak, is 352 +/- 52 keV.
A Band function fits the spectrum equally well
with Epeak= 256 +/- 51 keV, alpha = -1.28 +/- 0.08 and beta = -2.2 +/- 0.2.
The event fluence (10-1000 keV) in this time interval is
(1.08 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.7 s in the 10-1000 keV band is 16.4 +/- 0.9 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/"
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TITLE: GCN CIRCULAR
NUMBER: 34583
SUBJECT: GRB 230827A: GRBAlpha detection
DATE: 23/08/28 10:46:50 GMT
FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz>
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), yyT. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 230827A (Fermi/GBM detection: GCN 34575, INTEGRAL/SPI-ACS detection at 2023-08-27 ~18:17:53 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023; arXiv:2302.10048).
The detection was confirmed at the peak time 2023-08-27 18:18:14 UTC. The T90 duration measured by GRBAlpha is 73 s and the overall significance during T90 reaches 30 sigma.
The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB230827A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
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TITLE: GCN CIRCULAR
NUMBER: 34582
SUBJECT: Subject: GRB230826A: Swift/UVOT upper limits
DATE: 23/08/28 10:21:42 GMT
FROM: Alice Breeveld at MSSL-UCL <a.breeveld(a)ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and R. A. J. Eyles-Ferris (U Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230826A 114 s after the BAT trigger (Eyles-Ferris et al., GCN Circ. 34565).
No optical afterglow consistent with the enhanced XRT position (Osborne et al., GCN Circ. 34569) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 114 263 147 >20.0
white 606 5452 312 >20.4
v 657 1105 58 >17.8
b 582 5339 255 >19.6
u 327 5134 481 >19.5
uvw1 707 1320 71 >18.4
uvm2 682 1303 78 >18.4
uvw2 632 1254 78 >18.6
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.243 in the direction of the burst (Schlegel et al. 1998).
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TITLE: GCN CIRCULAR
NUMBER: 34581
SUBJECT: GRB 230827A: BALROG localization (Fermi Trigger / GRB 230827762)
DATE: 23/08/27 20:59:21 GMT
FROM: Jochen Greiner at MPE <jcgrog(a)mpe.mpg.de>
B. Biltzinger, T. Preis, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
at 18:17:52 on 27 Aug. 2023 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) = 320.1+/-0.9 deg
Decl.(2000.0) = -20.3+/-0.9 deg
We estimate an additional systematic error of 1 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB230827762/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB230827762/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB230827762/json
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TITLE: GCN CIRCULAR
NUMBER: 34580
SUBJECT: Fermi trigger No 714809315: Global MASTER-Net observations report
DATE: 23/08/27 20:30:43 GMT
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru>
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko,
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),
D. Buckley
(South African Astronomical Observatory),
O.A. Gres, N.M. Budnev
(Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov
(Blagoveschensk Educational State University)
MASTER-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB230827.26 (trigger No 714809315,19h 57m 16.80s , +56d 28m 12.0s, R=2.17) errorbox 43424 sec after notice time and 43457 sec after trigger time at 2023-08-27 18:12:48 UT, with upper limit up to 18.8 mag. The observations began at zenith distance = 16 deg. The sun altitude is -17.8 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB230827.26 errorbox 51151 sec after notice time and 51184 sec after trigger time at 2023-08-27 20:21:35 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 22 deg. The sun altitude is -35.7 deg.
The galactic latitude b = 14 deg., longitude l = 90 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2261201
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
43548 | 2023-08-27 18:12:48 | MASTER-Tavrida | (19h 46m 06.01s , +57d 21m 28.8s) | C | 180 | 18.8 |
51214 | 2023-08-27 20:21:35 | MASTER-Kislovodsk | (19h 48m 46.64s , +57d 14m 17.4s) | C | 60 | 17.4 |
51214 | 2023-08-27 20:21:35 | MASTER-Kislovodsk | (19h 48m 21.11s , +57d 37m 43.3s) | C | 60 | 14.8 |
51295 | 2023-08-27 20:22:55 | MASTER-Kislovodsk | (19h 48m 46.58s , +57d 12m 34.0s) | C | 60 | 17.0 |
51295 | 2023-08-27 20:22:55 | MASTER-Kislovodsk | (19h 48m 19.15s , +57d 35m 59.8s) | C | 60 | 16.3 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
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TITLE: GCN CIRCULAR
NUMBER: 34579
SUBJECT: GRB 230827.256: AKO Optical follow-up of ZTF23abaanxz (AT 2023qxj)
DATE: 23/08/27 19:53:53 GMT
FROM: Mohammad Odeh at Al Khatim Observatory M44 <mshodeh(a)gmail.com>
Mohammad Odeh, Osama Ghannam, Anas Mohammad, Khalfan Al-Noaimy, and Sameh
Al-Ashi, report on behalf of Al-Khatim Observatory (AKO) operated by the
International Astronomical Center in Abu Dhabi, UAE:
We observed ZTF23abaanxz (AT 2023qxj) discovered by ZTF (M. L. Li et al.,
GCN 34574) in the localization region of the Fermi GRB230827.256 (trigger
No 714809315), with our 0.36m f/7.7 robotic telescope. The observation was
done on 27 August 2023 starting from 18:12 (UT), about 12 hours after the
GRB trigger.
We obtained multiple 180-sec exposures in Ic and R filters. We detected the
candidate at the position reported by (M. L. Li et al., GCN 34574) and
confirmed by (Swain et al., GCN 34576).
The following observations were calculated using the Atlas catalogue as a
reference:
-----------------------------------------------------------------------------
ObsTime (mid), t(mid) – t(0) (hours), Exposure (sec), Filter, Mag
-----------------------------------------------------------------------------
2023-08-27T18:31:42Z, 12.4, 13 x 180s (stacked), Ic, 18.2 +/- 0.21
2023-08-27T19:19:30Z, 13.2, 16 x 180s (stacked), R, 19.1 +/- 0.23
-----------------------------------------------------------------------------
The magnitudes are not corrected for galactic extinction.
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TITLE: GCN CIRCULAR
NUMBER: 34577
SUBJECT: Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
DATE: 23/08/27 19:24:18 GMT
FROM: Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 <osservatorionastroverde(a)gmail.com>
Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy
in a large collaboration with:
M.G. Dainotti (National Astronomical Observatory of Japan),
Y. Niino (Tokyo University, Institute of Astronomy),
K. Kalinowski (Aarhus University, Department of Physics and Astronomy),
B. De Simone (Universita' degli Studi Di Salerno)
report:
Following the Swift trigger no. 1186959 (GCN 34537), we pointed at the coordinates RA(J2000)=17h 27m 46s: Dec(J2000)=-16d 12' 53" and started our observations with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy.
Member of:
AAVSO - American Association of Variable Star Observers.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.
AstroCampania Associazione.
The observations started at 19:23 UT of 2023/08/24, after about 5,25 hours after the GRB trigger, at the end of twilight with clear skies, with principal telescope SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME
I took 9 image of 120 sec each in fotometric V and 13 in Rc . All images, calibrated with masterdark and masterflat have been measured with Maxim DL software
We have detected a clear visible source at the enhanced position reported by Swift Burst Alert Telescope (BAT) (Page et al., GCN 34537 ) and by other telescopes ( Jamie A. Kennea (PSU) et al GCN 34540., S. Dichiara (PSU) et al GCN 34542, 34547, 34554,34555., Mohammad Odeh et al GCN 34543, 34561., H. Negoro (Nihon U). et al GCN 34544., Brendan O'Connor et al GCN 34549.,Dylan Dutton et al GCN 34556., T. M. Parsotan et al GCN 34557., U.Quadri et al GCN 34562., Claudio Lopresti et al GCN 34566., S. Leonini et al GCN 34573)
at following position
RA (J2000.0) 17:27:43.32
Dec (J2000.0) -16:12:19
with the following photometry:
JD Mag Filter
2460181.317 13.69 V
2460181.32 13.74 V
2460181.323 13.66 V
2460181.326 13.59 V
2460181.329 13.63 V
2460181.332 13.55 V
2460181.335 13.54 V
2460181.338 13.62 V
2460181.341 13.55 V
JD Mag Filter
2460181.309 13.49 Rc
2460181.31 13.51 Rc
2460181.312 13.54 Rc
2460181.313 13.45 Rc
2460181.315 13.47 Rc
2460181.318 13.48 Rc
2460181.321 13.50 Rc
2460181.324 13.52 Rc
2460181.33 13.45 Rc
2460181.333 13.46 Rc
2460181.336 13.50 Rc
2460181.339 13.50 Rc
2460181.342 13.50 Rc
The magnitudes are calibrated with stars of the PanSTARRS catalog, espressed in AB system and are not corrected for the expected Galactic extinction.
The peculiar transient ( detected by other observatories ) is confirmed in our observations. Further observations are encouraged.
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