TITLE: GCN CIRCULAR
NUMBER: 39078
SUBJECT: GRB 250129A: OHP/T193 optical and spectroscopy observations
DATE: 25/01/29 10:51:22 GMT
FROM: Benjamin Schneider at MIT <bschn(a)mit.edu>
B. Schneider (LAM), C. Adami (LAM/Pytheas/AMU), J. Balcaen (OHP/Pytheas), A. Saccardi (CEA/Irfu), E. Le Floc'h (CEA/Irfu), J. Schmitt (OHP/Pytheas), J. P. Palmerio (CEA/Irfu), S. Basa (LAM/OHP/Pytheas/AMU), D. Turpin (CEA/Irfu) report on behalf of a larger collaboration:
We observed the field of the GRB 250129A (Beardmore et al., GCN 39066) with the T193 cm telescope at the Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. We obtained one exposure of 60s in the i-band using the red MISTRAL setting at 2025-01-29T05:14:39 (30 min after the trigger).
In the reduced image, the optical afterglow (Francile et al., GCN 39065; Schneider et al., GCN 39071; Belkin et al., GCN 39072; Izzo et al., GCN 39073; Izzo et al., GCN 39074; Ghosh et al., GCN 39077) is clearly detected at:
i = 16.34 +/- 0.02 mag (AB)
The photometric calibration was performed using nearby stars from the PanSTARRS catalog and is not corrected for Galactic extinction.
In addition, we obtained 15 min exposures during the twilight with the MISTRAL spectroscopic red setting, covering from 6400 to 9950 AA. In a preliminary reduction of the spectrum, the continuum is detected but the low S/N makes the redshift estimate difficult. Given the redshift provided by Schneider et al. (GCN 39071) and Izzo et al. (GCN 39073), we likely detected FeII (@2600 AA) and a hint of the MgII doublet at a corresponding redshift of 2.15.
We acknowledge the excellent support from Observatoire de Haute-Provence, in particular the Sophie observer Alice Radcliffe.
View this GCN Circular online at https://gcn.nasa.gov/circulars/39078.
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TITLE: GCN CIRCULAR
NUMBER: 39077
SUBJECT: GRB 250129A: Early afterglow detection by LCO.
DATE: 25/01/29 09:12:17 GMT
FROM: ankur ghosh at CAPP, University of Johannesburg <ghosh.ankur1994(a)gmail.com>
Ankur Ghosh, Soebur Razzaque (CAPP, University of Johannesburg), Alexander Moskvitin, Yulia Sotnikova (SAO RAS), Naveen Dukiya (ARIES), Rahul Gupta (NASA GSFC) on behalf of a larger collaboration.
We observed the field of the GRB 250129A triggered by Swift (Beardmore et al., GCN 39066) in V, r filters of the 0.4-m SCICAM QHY600 at the Las Cumbres Observatory Global Telescope (LCOGT) node located at Teide Observatory, Tenerife. The 0.4 m SCICAM QHY600 is equipped with 9576 x 6388 pixel CCD (FOV: 1.9 x 1.2 degrees, scale: 0.74 arcsec/pixel) but we only used the FOV of 30 x 30 arcmin for our observation.
Observations began on January 29, 2025, starting 1.17 hours after the GRB trigger.
We clearly detect the optical transient (OT) reported by GCNs ( Francile, GCN 39065; Schneider et al., GCN 39071; Belkin et al., GCN 39072; Izzo et al., GCN 39073, Izzo et al., GCN 39074) in our V, r band images. Follow-up observations are on going.
|Date| |UTstart| |t-T0 (hours)| |Exp (sec)| |Filter| |Magnitude|
---------------------------------------------------------------------------------------------------
2025-01-29 05:55:21.79 1.17 1 x 600 r r = 17.05 +/- 0.01
2025-01-29 06:22:59.80 1.63 1 x 600 V V = 17.34 +/- 0.01
The field was calibrated against nearby APASS stars, with magnitudes converted using Lupton (2005) equations, and has not been corrected for Galactic extinction.
View this GCN Circular online at https://gcn.nasa.gov/circulars/39077.
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TITLE: GCN CIRCULAR
NUMBER: 39076
SUBJECT: GRB 250128B: OHP/T193 optical upper limit
DATE: 25/01/29 09:08:55 GMT
FROM: Christophe Adami at LAM <christophe.adami(a)lam.fr>
C. Adami (LAM/Pytheas/AMU), B. Schneider (LAM), S. Basa (LAM/OHP/Pytheas/AMU), E. Le Floc'h (CEA/Irfu), A. Saccardi (CEA/Irfu), D. Turpin (CEA/Irfu), F. Schussler (CEA Paris-Saclay), M. Dennefeld (IAP), J. Palmerio (CEA/Irfu) report on behalf of a larger collaboration:
We observed the field of the GRB250128B (Fermi GBM team, GCN 39057; Evans et al., GCN 39058; Izzo et al., GCN 39059; Lipunow et al., GCN 39061; Ulaczyk et al., GCN 39062; Muers et al., GCN 39063; Osborne et al., GCN 39064; Lipunov et al., GCN 39067; Evans et al., GCN 39069) with the T193cm telescope at the Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. We obtained a total of 2490sec (1x30s + 1x300s + 3x720s) in the i-band using the red MISTRAL setting from 20250129_043822UT to 20250129_050703UT (mid-time ~12.5h after the trigger).
In the stacked image, we do not detect any new source at the XRT source position (Evans et al., GCN 39069) down to the following 3-sigma limit:
i > 20.6
The photometric calibration was performed using nearby stars from the PanSTARRS catalog.
We acknowledge the excellent support from Observatoire de Haute-Provence, in particular Jean Balcaen, and the Sophie observer Alice Radcliffe
View this GCN Circular online at https://gcn.nasa.gov/circulars/39076.
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TITLE: GCN CIRCULAR
NUMBER: 39075
SUBJECT: Swift GRB250119A: Global MASTER-Net Slowly evolving LC detection
DATE: 25/01/29 07:57:36 GMT
FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru>
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix
Aguilar (OAFA),
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, D.Vlasenko, I.Panchenko,
A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina (Lomonosov MSU),
O.Gress, N.Budnev(ISU),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 250129A ( A. P. Beardmore et al., GCN 39066, Francile et al., GCN 39065) error box.
The automatic light curve is a slowly evolving light curve with a flat maximum (~16.5m, clear filter like to the Sloan "g") at ~40 min after trigger. Redaction is continuated.
View this GCN Circular online at https://gcn.nasa.gov/circulars/39075.
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TITLE: GCN CIRCULAR
NUMBER: 39074
SUBJECT: GRB 250129A: LCO optical observations
DATE: 25/01/29 07:54:21 GMT
FROM: luca.izzo(a)inaf.it
L. Izzo (INAF-OACn and DARK/NBI), and D. B. Malesani (DAWN/NBI and Radboud Univ.) report:
We observed the field of GRB 250129A (Beardmore et al., GCN #39066) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at the Cerro Tololo Observatory, Chile. Observations started on 2025 January 29 at 06:40 UT (1.89 hr after the GRB trigger). We obtained a single image of 240 s exposure in each of the SDSS-r and SDSS-i filters.
We detect a bright source consistent with the position of the optical afterglow reported by Swift-UVOT (Beardmore et al., GCN #39066) and by other ground-based facilities (Francile, GCN #39065; Schneider et al., GCN #39071; Belkin et al., GCN #39072; Izzo et al., GCN #39073). We measure preliminary magnitudes of r = 17.27 +/- 0.02 mag and i = 17.04 +/- 0.03 (AB), calibrated against nearby stars from the Pan-STARRS catalog.
This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719. We also acknowledge the use of the ECSnoopy package by E. Cappellaro.
View this GCN Circular online at https://gcn.nasa.gov/circulars/39074.
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TITLE: GCN CIRCULAR
NUMBER: 39073
SUBJECT: GRB 250129A: NOT optical observations and redshift confirmation
DATE: 25/01/29 07:32:00 GMT
FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl>
Luca Izzo (INAF/OACn and DARK/NBI), Daniele B. Malesani (DAWN/NBI), Kasper E. Heintz (DAWN/NBI), Benjamin Gompertz (Birmingham), Antonio de Ugarte Postigo (CNRS, LAM and OCA), Benjamin N. Hauptmann (NOT, DTU Space ), Arthur M. Kadela (NOT, NBI), report on behalf of a larger collaboration:
We observed the optical counterpart (Francile, GCN 39065; Belkin et al., GCN 39072) of GRB 250129A (Beardmore et al., GCN 39066) using the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. In a 300-s exposure with mid time 2025 Jan 29.222 UT (34.3 min after trigger), the counterpart is well detected with an AB magnitude r = 16.71 +- 0.02 (calibrated against nearby stars from Pan-STARRS). We measure the following coordinates (J2000):
RA = 13:14:42.40
Dec = +05:01:50.2
A sequence of three 1200-s spectra was secured using grism #4. Bright continuum is detected across the whole wavelength range. A number of absorption lines are detected, which, among others, we identify as H I, Si II, O I, C II, Si IV, C IV, Al II, Fe II, Mg II, all at a common redshift z = 2.15.
Our result is consistent with the value already measured by Schneider et al. (GCN 39071).
View this GCN Circular online at https://gcn.nasa.gov/circulars/39073.
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TITLE: GCN CIRCULAR
NUMBER: 39072
SUBJECT: GRB 250129A: GOTO optical observations show brightening afterglow
DATE: 25/01/29 07:30:35 GMT
FROM: Ben Gompertz at U of Birmingham <b.gompertz(a)bham.ac.uk>
S. Belkin, B. P. Gompertz, D. O'Neill, R. Starling, K. Ackley, M. J. Dyer, J. Lyman, A. Kumar, K. Ulaczyk, F. Jimenez-Ibarra, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Palle and D. Pollacco report on behalf of the GOTO collaboration:
We report on optical observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022; Dyer et al. 2024) in response to the Swift detected GRB 250129A (Beardmore et al., GCN 39066). Targeted imaging obtained with GOTO-North covered the Swift localisation region starting at 2025-01-29 04:47:52 (+2.7m post trigger) with an average 5-sigma depth of 20.1 mag. The observations 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 deeper template observations of the same pointings.
We detect the optical afterglow reported by UVOT, also detected by Schnieder et al. (GCN 39071), in two epochs centred at 5.2 minutes and 1.22 hours after trigger. The measured AB magnitudes are L = 17.86 ± 0.03 and L = 17.11 ± 0.02 respectively. The afterglow has therefore brightened by approximately 0.75 magnitudes over this period. Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
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).
View this GCN Circular online at https://gcn.nasa.gov/circulars/39072.
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TITLE: GCN CIRCULAR
NUMBER: 39071
SUBJECT: GRB 250129A: VLT/X-shooter redshift of z = 2.151
DATE: 25/01/29 07:24:10 GMT
FROM: Benjamin Schneider at MIT <bschn(a)mit.edu>
B. Schneider (LAM), A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud Univ.), S. D. Vergani (CNRS, Obs. Paris/LUX), N. R. Tanvir (U. Leicester), V. D’Elia (ASI-SSDC and INAF-OAR), A. de Ugarte Postigo (CNRS, OCA and LAM), L. Izzo (INAF-OACn and DARK/NBI) report on behalf of the Stargate collaboration:
We observed the optical afterglow (Francile et al., GCN 39065) of GRB 250129A (Beardmore et al., GCN 39066) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Observations were performed via the rapid-response mode (RRM) system. Our spectra cover the wavelength range 3000-25000 AA, and consist of 4x600 s. The observation mid time was 2025 Jan 29.2528 UT (1.315 hr after the GRB).
In a 5 s image taken with the acquisition camera on Jan 29.237 UT, we detect the optical afterglow, for which we measure a magnitude r =16.72 +- 0.02 AB (calibrated against nearby stars from the Pan-STARRS catalogue).
In a preliminary reduction of the spectra, we clearly detect a continuum over the entire wavelength range. From the detection of a broad Lya absorption at ~3830 AA and multiple absorption features, which we interpret as due to N V, Si II, Si II*, O I, O I*, C II, C II*, Al II, Si IV, C IV, Fe II, Fe II*, Mg II, we infer a common redshift of z = 2.151.
We notice the presence of at least one intervening system at z = 1.89, as identified by an additional Lya absorption and multiple absorption lines (C II, Si II, Fe II, Al II, and Mg II).
We acknowledge expert support from the ESO staff in Paranal, in particular Abel de Burgos, Celia Desgrange, Luca Sbordone, Robert Klement, Rodrigo Palomino, and Sam Kim.
View this GCN Circular online at https://gcn.nasa.gov/circulars/39071.
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TITLE: GCN CIRCULAR
NUMBER: 39069
SUBJECT: GRB 250128B: Enhanced Swift-XRT position
DATE: 25/01/29 06:15:52 GMT
FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk>
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1514 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 250128B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 231.42540, -0.53929 which is equivalent
to:
RA (J2000): 15h 25m 42.10s
Dec (J2000): -00d 32' 21.4"
with an uncertainty of 2.7 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
View this GCN Circular online at https://gcn.nasa.gov/circulars/39069.
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