December 2024 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 36718] GRB241229B: UVOT upper limits
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38717 SUBJECT: GRB241229B: UVOT upper limits DATE: 24/12/29 23:57:41 GMT FROM: Paul Kuin at MSSL <npkuin(a)gmail.com> N. P. M. Kuin (UCL-MSSL) and A. D'Ai (INAF-IASFPA SSDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began observations of the field of GRB 241229B 6.5 hours after the BAT trigger due to an observing constraint (D'Elia et al., GCN Circ. 38699). No optical afterglow consistent with the XRT position (Evans, GCN Circ. no 38708) was detected with UVOT. 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 b 23500 39885 1686 >21.5 uvw1 27820 45505 1800 >21.0 u 28727 45738 404 >20.3 uvw2 33481 51179 1800 >21.2 v 34386 51381 376 >20.0 white 39890 40021 132 >20.9 b 55868 56383 254 >20.7 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/38717. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36717] GRB 241229C: Fermi GBM Final Real-time Localization
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38716 SUBJECT: GRB 241229C: Fermi GBM Final Real-time Localization DATE: 24/12/29 23:38:14 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely SHORT GRB At 23:27:37 UT on 29 Dec 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241229C (trigger 757207662.335616 / 241229978). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 219.8, Dec = 15.3 (J2000 degrees, equivalent to J2000 14h 39m, 15d 18'), with a statistical uncertainty of 16.2 degrees. The angle from the Fermi LAT boresight is 12.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241229978/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241229978/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241229978/… View this GCN Circular online at https://gcn.nasa.gov/circulars/38716. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36716] GRB 241228B: D50 optical detection
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38715 SUBJECT: GRB 241228B: D50 optical detection DATE: 24/12/29 22:35:20 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek(a)asu.cas.cz> J. Strobl and M. Jelinek (ASU CAS Ondrejov) report: We observed the position of the Fermi/GBM-detected GRB 241228B (Fermi GBM team, GCN 38682) observed also by Swift/XRT (Evans, GCN 38688) with the D50 telescope of the Astronomical Institute in Ondřejov, near Prague, Czech Republic. Our observation started 16.4 h after the initial trigger and was performed with an SDSS r' filter. We detect the optical counterpart (Kumar et al., GCNs 38684 and 38691; An et al., GCN 38687; Ortega-Casas et al., GCN 38692; Ghosh et al., GCN 38702; Xu et al., GCN 38704) in multiple combined 24x120 s frames obtained between 16.4 and 21.9 h after the trigger. Based on our observations, at 18 h after trigger the source had r' = 20.4 +/- 0.1 (AB). View this GCN Circular online at https://gcn.nasa.gov/circulars/38715. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36715] GRB 241228B: Fermi GBM Observation
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38714 SUBJECT: GRB 241228B: Fermi GBM Observation DATE: 24/12/29 21:37:56 GMT FROM: Lorenzo Scotton at UAH <lscottongcn(a)outlook.com> L. Scotton (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 04:13:05.39 UT on 28 December 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241228B (trigger 757051990/241228176), which was also detected by Swift/BAT-NITRATES (J. DeLaunay et al. 2024, GCN 38700). The Fermi GBM on-ground location is consistent with the Swift/BAT-NITRATES position. Follow-up observations report the detection of the potential afterglow (Kumar et al. GCN 38684 and GCN 38691; An et al. GCN 38687; Ortega-Casas et al. GCN 38692; Mohan et al. GCN 38694; Ghosh et al. GCN 38702, Burrows et al. GCN 38713) at a redshift z = 2.674 (An et al. GCN 38704). The angle from the Fermi LAT boresight is 49 degrees. The GBM light curve consists of two emission episodes, with a duration (T90) of about 19.5 s (50-300 keV). The time-averaged spectrum from T0-0.7 to T0+23.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.86 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 440 +/- 10 keV. The event fluence (10-1000 keV) in this time interval is (4.66 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+4.2 s in the 10-1000 keV band is 15.1 +/- 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/" View this GCN Circular online at https://gcn.nasa.gov/circulars/38714. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36714] GRB 241228B: Swift-XRT afterglow detection
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38713 SUBJECT: GRB 241228B: Swift-XRT afterglow detection DATE: 24/12/29 21:04:55 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> D.N. Burrows (PSU), M. A. Williams (PSU), S. Dichiara (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/GBM-detected burst GRB 241228B. We searched for X-ray sources in 1.8 ks of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 1.8 ks, obtained between T0+40.0 ks and T0+41.8 ks. An uncatalogued X-ray source is detected within the estimated 3-sigma Fermi/GBM error region. Using 1809 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 127.77288, +6.84823 which is equivalent to: RA (J2000): 08h 31m 05.49s Dec(J2000): +06d 50' 53.6" with an uncertainty of 3.2 arcsec (radius, 90% confidence). This position is 0.6 arcsec from the optical source GOTO24jmz and is believed to be the afterglow. The light curve is consistent with a constant source of mean count rate 5.7e-02 ct/sec. A power-law fit gives an index of -1.281 (+4.492, -0.030). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.4 (+0.5, -0.3). The best-fitting absorption column is 3 (+15, -0) x 10^20 cm^-2, consistent with the Galactic value of 2.9 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.8 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3 (+15, -0) x 10^20 cm^-2 Galactic foreground: 2.9 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.4 (+0.5, -0.3) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021750. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021750. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38713. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36713] GRB 241229B: Fermi GBM Observation
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38712 SUBJECT: GRB 241229B: Fermi GBM Observation DATE: 24/12/29 18:21:40 GMT FROM: Peter Veres at University of Alabama in Huntsville <veresp(a)gmail.com> Peter Veres (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 01:36:16.06 UT on 29 December 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241229B (trigger 757128981/241229067). which was also detected by Swift BAT (H. A. Krimm et al. 2024, GCN 38699). The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 39 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 6 s (50-300 keV). The time-averaged spectrum from T0-5.1 to T0+4.1 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.7 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 76 +/- 5 keV. The event fluence (10-1000 keV) in this time interval is (1.24 +/- 0.06)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.064 s in the 10-1000 keV band is 6.1 +/- 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/" View this GCN Circular online at https://gcn.nasa.gov/circulars/38712. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36712] GRB 241229A: Swift ToO observations
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38711 SUBJECT: GRB 241229A: Swift ToO observations DATE: 24/12/29 18:17:48 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the SVOM/ECLAIRs GRB 241229A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021751 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the SVOM/ECLAIRs event. 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/38711. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36711] GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38710 SUBJECT: GRB 241229B: NUTTelA-TAO / BSTI Optical Limits DATE: 24/12/29 16:53:38 GMT FROM: Toktarkhan Komesh at Nazarbayev University <toktarkhan.komesh(a)nu.edu.kz> T. Komesh (NU), Z. Abdullayev (NU), Z. Maksut (NU), B. Grossan (UCB, NU), D. Berdikhan (NU), M. Krugov (FAI) and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory: The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at GRB 241229B on receipt of an automated GCN / BAT position alert, observing in Sloan g' and r' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14). We started observations at 01:37:16 UT on 2024-12-29, 61 s after the BAT trigger. Observations were made in partly cloudy conditions. No source consistent with the XRT (P.A. Evans et al., GCN Circ. 38708) was detected. We report the following results: start time t-t0(s) end time UL g' UL r' exposure_time (s) -------------------------------------------------------------- 01:37:16 61 1:37:41 - 16.67 25 01:38:25 135 1:40:25 16.21 17.35 120 The start and end time is in UT. t is the middle time, t0 is the BAT trigger time, t-t0 is given in seconds. UL gives the 5 sigma upper limit sensitivity in magnitudes, for images co-added to the given exposure time. The first row in the table corresponds to co-adds of an initial short exposure image sequence of 1 s (these sub-second exposures are read-noise suppressed by our EMCCD cameras, with high gain electron multiplication active; other images are taken in conventional CCD operation mode) for r'. The second row corresponds to co-adds from a continuing series of 15 s exposures for g' and r’. Calibration was done with 3 Pan-STARRS catalog stars on our images. No color or other corrections were applied to the values above. ---------------------------------- NU = Nazarbayev University, Astana, Kazakhstan UCB = University of California, Berkeley, USA FAI = Fesenkov Astrophysical Institute, Kazakhstan This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP14870504). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan. View this GCN Circular online at https://gcn.nasa.gov/circulars/38710. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36710] GRB 241228A: Mondy optical afterglow observations
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38709 SUBJECT: GRB 241228A: Mondy optical afterglow observations DATE: 24/12/29 16:43:08 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex(a)gmail.com> A. Volnova (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE) report on behalf of GRB IKI FuN: We observed the field of GRB 241228B triggered by Fermi (Fermi GBM team, GCN 38682) with AZT-33IK telescope of Mondy observatory in R-filter starting on (UT) 2024-12-28 19:42:31. We clearly detect optical afterglow (Kumar et al., GCN 38684 and GCN 38691; An et al. GCN 38687; Ortega-Casas et al., GCN 38692; Ghosh et al., GCN 38702; An et al., GCN 38704). Preliminary photometry of the afterglow is the following Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2024-12-28 19:42:31 0.66628 30x120 R 20.28 0.04 23.0 The photometry is based on nearby SDSS DR16 stars (R mags by Lupton transformation). View this GCN Circular online at https://gcn.nasa.gov/circulars/38709. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36709] GRB 241229B: Swift-XRT refined Analysis
by GCN Circulars 29 Dec '24

29 Dec '24

TITLE: GCN CIRCULAR NUMBER: 38708 SUBJECT: GRB 241229B: Swift-XRT refined Analysis DATE: 24/12/29 14:06:47 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: We have analysed 2.7 ks of XRT data for GRB 241229B, from 23.5 ks to 34.3 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The refined XRT position is RA, Dec = 274.1761, +74.6833 which is equivalent to: RA (J2000): 18 16 42.26 Dec(J2000): +74 40 60.0 with an uncertainty of 6.8 arcsec (radius, 90% confidence). The source has a mean count rate of 1.4e-02 ct/sec; we cannot determine at the present time whether it is fading. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01277428. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38708. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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