GRB 231024A
GCN Circular 34928
Subject
GRB 231024A: GRANDMA observations of AT2023vuc/GOTO23baj candidate
Date
2023-11-02T13:35:29Z (2 years ago)
From
Dalya Akl at American Uni. SHJ <dalyaakl.d@gmail.com>
Via
Web form
D. Akl (AUS), D. Turpin (CEA-Saclay/Irfu), P. Gokuldass (ERAU), R. Strausbaugh (EUI), Z. Vidadi (ShAO), S. Antier, A. de Ugarte Postigo (OCA/Artemis), M. Coughlin (UMN), Q. Andre (OCA), J. Peloton, P. Hello (IJCLAB), I. Tosta e Melo (UniCT-DFA), T. Pradier(Unistra/IPHC), S. Karpov, M. Prouza, M. Mašek, M. Blazek (FZU), A. Klotz (IRAP), A. Takey, M. Ismail, M. Abdelkareem, M. Molham (NRIAG), L. Almeida, L. Fraga, W. Corradi, N. Sasaki (LNA), F. Navarete (NOIRLab/SOAR), M. Freeberg (KNC) on behaf of the GRANDMA and Kilonova-Catcher collaborations:
The GRANDMA and Kilonova-Catcher telescope networks observed the source GOTO23baj/SN2023vuc (Gompertz et al., GCN 34878, Iglesias-López et al, GCN 34881), finally classified as a young supernova (Saccardi et al, GCN 34882). We used Skyportal (Coughlin et al., 2023) for the coordination of our observations.
Observations were conducted from 2023-10-25 17:15:51 to 2023-11-01 03:00:12, ~0.91-7.15 days after the GOTO detection time (midtime ref = 2023-10-24T23:23:27.50 from Gompertz et al., GCN 34878).
In the following table, we report a subset of the preliminary photometry of our observations. Magnitudes are reported in the AB and Vega system depending on the filter set.
T-T0 day|MJD |Obser. |Exposure|Filter | Mag +/- err
--------------------------------------------------------------------------
0.91 |60242.886 | Les Makes |50X120s | r | 18.56+/-0.19 (AB)
1.04 |60243.019 | FRAM-CTA-N |76x120s | V | 18.51 U.L (Vega)
5.32 |60247.290 | KNC-T11 |17x180s | Rc | 18.03+/-0.09 (Vega)
5.92 |60247.889 | KAO |11x180s | r | 18.27+/-0.01 (AB)
5.96 |60247.932 | KAO |11x180s | i | 18.51+/-0.02 (AB)
6.23 |60248.206 | KNC-T11 |17x180s | Rc | 18.17+/-0.08 (Vega)
6.81 |60248.793 | KAO |15x180s | i | 18.46+/-0.01 (AB)
6.85 |60248.829 | KAO |14x180s | r | 18.42+/-0.01 (AB)
7.13 |60249.105 | SOAR |5x75s | r | 18.33+/-0.01 (AB)
7.14 |60249.111 | SOAR |3x150s | i | 18.37+/-0.01 (AB)
7.14 |60249.117 | SOAR |3x200s | g | 18.03+/-0.01 (AB)
7.15 |60249.125 | SOAR |2x120s | z | 18.64+/-0.05 (AB)
Our images were taken under poor conditions and a bright moon. All the data in Sloan filters have been calibrated with respect to the PS1 catalog. Johnson filters have been measured using the Gaia catalog. All the data have been reduced by a single data processing pipeline STDPIPE (Karpov et al., 2022). Please contact us for more information and collaboration on this source.
GRANDMA is a worldwide coordinated telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
GCN Circular 34910
Subject
GRB 231024A: AKO Optical Counterpart Candidate
Date
2023-10-30T12:04:57Z (2 years ago)
From
Mohammad Odeh at Al Khatim Observatory M44 <mshodeh@gmail.com>
Via
legacy email
Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International
Astronomical Center in Abu Dhabi, UAE), and Dalya Akl, Ilmah Abdi, and
Nidhal Guessoum (American University of Sharjah, UAE), report:
We observed the field of GRB 231024A (Fermi GBM Team, GCN 34876; Gompertz
et al., GCN 34878; Iglesias-López et al., GCN 34881; Saccardi et al., GCN
34882; Scotton et. al., GCN 34885) with our 0.36m f/7.7 robotic telescope.
The observation was done on 29 October 2023 from 17:31 UT to 19:14 UT, 5.21
days after the trigger. We obtained 32x180 sec. images using (Ic) filter.
We detected the optical afterglow candidate of GRB 231024A in our stacked
images at the coordinates (J2000.0): R.A.: 00:55:07.28, Dec.: -15:15:19.6,
which is consistent with the observation of (Gompertz et al., GCN 34878).
The following magnitude was calculated using the Atlas catalogue as a
reference:
-----------------------------------------------------------------------------
ObsTime (mid), Exposure (sec), Filter, Mag, MagRMS
-----------------------------------------------------------------------------
2023-10-29T18:24:01Z, 32x180s (stacked), Ic, 18.3, 0.16
-----------------------------------------------------------------------------
The magnitude is not corrected for galactic extinction.
GCN Circular 34885
Subject
GRB 231024A: Fermi GBM Observation
Date
2023-10-25T19:47:00Z (2 years ago)
From
Lorenzo Scotton at UAH <lscottongcn@outlook.com>
Via
Web form
L. Scotton (UAH), O.J. Roberts (USRA/NASA-MSFC), C. Fletcher (USRA),
E. Burns (LSU) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 13:20:34.42 UT on 24 October 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231024A (trigger 719846439/231024556). This trigger
was later followed up by GOTO (Gompertz et al. 2023, GCN 34878),
LCOGT and ZTF (Iglesias-López et al. 2023, GCN 34881),
and X-shooter (Saccardi et al. 2023, GCN 34882) identifying
a candidate afterglow (AT2023vuc/GOTO23baj) and suggested it was the counterpart.
The Fermi GBM Final Localization was reported in GCN 34876.
The angle from the Fermi LAT boresight is 89 degrees.
The GBM light curve consists of a single peak
with a duration (T90) of about 0.05s. The time-averaged spectrum
from T0-0.064 to T0+0.064 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.76 +/- 0.26 and the cutoff energy,
parameterized as Epeak, is 516 +/- 202 keV.
A Band function fits the spectrum equally well with
Epeak = 519 +/- 203 keV, alpha = -0.75 +/- 0.26 and beta = -8.82 +/- 0.01.
The event fluence (10-1000 keV) in this time interval is
(2.9 +/- 0.4)E-07 erg/cm^2. The 64-msec peak photon flux measured
starting from T0-0.06 s in the 10-1000 keV band is 8 +/- 1 ph/s/cm^2.
Due to the large GBM localization error radius of 12.6 degrees,
as reported in GCN 34876, we are currently unable to confirm or deny
the association between GRB 231024A and AT2023vuc/GOTO23baj.
However, considered the spectroscopic classification of the optical transient
as an early supernova we expect it to be unrelated to the gamma-ray trigger.
The alignment in time and space is likely coincidental, in part due
to the large localization region.
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 34882
Subject
GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
Date
2023-10-25T14:50:13Z (2 years ago)
From
Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>
Via
Web form
A. Saccardi (GEPI/Paris Obs.), G. Leloudas (DTU Space), A. J. Levan (Radboud Univ. and Warwick Univ.), L. Izzo (INAF Napoli and DARK/NBI), A. de Ugarte Postigo (OCA), B. P. Gompertz (Birmingham), P. Jonker (Radboud Univ.), J. Palmerio (GEPI/Paris Obs.), E. Pian (INAF/OAS), G. Pugliese (Amsterdam), K. Wiersema (Univ. Herfordshire), R. A. M. J. Wijers (Amsterdam), report on behalf of a larger collaboration:
Following the discovery of GOTO23baj/AT2023vuc (Gompertz et al. 2023, GCN 34878; Iglesias-López et al., GCN 34881) within the error box of GRB 231024A (Fermi GBM Team, GCN 34876), we obtained a spectrum of the optical counterpart candidate with X-shooter. Observations started at 07:58 UT on 2023 Oct 25.
The spectrum is dominated by emission lines, that can be interpreted as strong He II 4686 (with a blue shoulder possibly associated with NIII / CIII) together with H-alpha and H-beta on top of a blue continuum, at a common redshift z = 0.056. The spectrum is consistent with those of very young supernovae that demonstrate flash-ionisation features a few hours to days after shock breakout (e.g. Gal-Yam et al. 2014, Nature, 509, 471). This is consistent with the non detection of the transient by ATLAS just 8 hours prior to the GOTO discovery. A comparison with SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows that the best matching template is that of SN 1998S at 12 days before maximum. Based on photometry reported by Iglesias-López et al. (GCN 34881), the transient absolute magnitude is around M_r = -18.8 (AB).
Considering the large GRB uncertainty region (12.6 deg radius) and its short duration, GOTO23baj/AT2023vuc is likely unrelated to GRB 231024A. However, this is a very young supernova and further observations are encouraged.
We acknowledge expert support from the ESO observing staff in Paranal, in particular Jonathan Smoker, Matias Jones and Felipe Gaete.
GCN Circular 34881
Subject
GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
Date
2023-10-25T14:05:57Z (2 years ago)
From
ipf@iac.es
Via
Web form
A. Iglesias-López, H. Akoudad-Ekajouan, C. Araujo-Álvarez, C. Arrizabalaga-Díaz-Caneja, F. Barnes-Sánchez, P. Eguiguren-Arrizabalaga, G.A. Jaimes-Illanes, P. Jiménez-Sánchez, S. Lamolda-Mir, A. Mang-Román, G. Marrero-Ramallo, P.P. Meni-Gallardo, I. Ruiz-Cejudo (ULL), M. Sánchez-Andújar (ULL and IAC), V. Wienzek (ULL), E. Esparza-Borges, F. Tinaut-Ruano, and I. Pérez-Fournon (IAC and ULL) report:
We report LCOGT and ZTF detections of GOTO23baj, the GOTO optical counterpart candidate of GRB 231024A.
The likely SHORT GRB 231024A has been reported by the Fermi GBM Team (GCN 34876). Gompertz et al. (GCN 34878) have reported a GOTO optical counterpart candidate, GOTO23baj (AT 2023vuc), at RA (J2000) = 00:55:07.30, Dec (J2000) = -15:15:19.43 and L = 18.37 +/- 0.07 on 2023-10-24 22:15:30.
We triggered Las Cumbres Observatory follow-up imaging and detected a source at the position of GOTO23baj on UT 2023-10-25 07:23:31 at SDSS r' = 18.28 +/- 0.12 in a single 300 sec exposure using one of the Las Cumbres Observatory 40 cm telescopes at Heleakala Observatory (Maui, Hawaii).
This transient has also been detected by ZTF (ZTF23abnevza) on UT 2023-10-25 07:42:27 at ZTF g = 18.193 ± 0.082.
This work makes use of observations from the Las Cumbres Observatory global telescope network (program IAC2023B-001) and is based on observations made with the Las Cumbres Observatory's education network telescopes that were upgraded through generous support from the Gordon and Betty Moore Foundation. These observations are part of a course in Astrophysical Techniques of the Master in Astrophysics of the Astrophysics Department of the University of La Laguna and Instituto de Astrofisica de Canarias (Tenerife, Canary Islands, Spain).
GCN Circular 34878
Subject
GRB 231024A: GOTO optical counterpart candidate
Date
2023-10-25T06:23:08Z (2 years ago)
From
Ben Gompertz at U of Birmingham <b.gompertz@bham.ac.uk>
Via
email
B. P. Gompertz, K. Ackley, D. K. Galloway, T. Killestein, R. Starling, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, A. Kumar, D. O'Neill, D. Steeghs, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Observer (GOTO, Steeghs et al. 2022) in response to GRB 231024A (Fermi GBM Team, GCN 34876). Targeted observations were performed by GOTO-North between 22:15:31 UT on 2023-10-24 and 00:31:24 UT on 2023-10-25 (starting 0.37 days after trigger). Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks.
We identify one candidate optical counterpart within the GBM 90% localisation region that is not present prior to the GRB trigger time in previous GOTO observations, the ZTF observations provided by the Lasair broker (Smith et al. 2019), or the ATLAS forced photometry server (Shingles et al. 2021). The most recent observation of the field was taken by ATLAS at 05:05:19 UT on 2023-10-24, 8.25 hours before trigger.
Name | RA(J2000) | Dec(J2000) | Filter | Mag(AB)
GOTO23baj | 00:55:07.30 | -15:15:19.43 | L | 18.37 +/- 0.07
The source is consistent with a galaxy in the WISExSuperCOSMOS PhotoZ SVM catalogue (Bilicki et al., 2016) with a reported redshift of z = 0.0734 +/- 0.0354 and is consistent with a power-law decay with an index of t^-0.7 across 3 epochs of observations.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
Observations are ongoing.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).
GCN Circular 34876
Subject
GRB 231024A: Fermi GBM Final Localization
Date
2023-10-24T21:38:20Z (2 years ago)
From
Lorenzo Scotton at UAH <lscottongcn@outlook.com>
Via
Web form
The Fermi GBM team reports the detection of a likely SHORT GRB
"At 13:20:34.42 UT on 24 October 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 231024A (trigger 719846439/231024556).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 15.4, Dec = -14.1 (J2000 degrees, equivalent to J2000 01h 01m, -14d 05'),
with a statistical uncertainty of 12.6 degrees.
The angle from the Fermi LAT boresight is 89.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231024556/quicklook/glg_skymap_all_bn231024556.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231024556/quicklook/glg_healpix_all_bn231024556.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn231024556/quicklook/glg_lc_medres34_bn231024556.gif"