February 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 37216] GRB 250207B: Tiled Swift observations
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39207 SUBJECT: GRB 250207B: Tiled Swift observations DATE: 25/02/07 16:37:22 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 series of observations, tiled on the sky, of the MAXI GRB 250207B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00131 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the MAXI event is high: 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/39207. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37215] LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39206 SUBJECT: LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume DATE: 25/02/07 16:10:21 GMT FROM: David Cook at Caltech/IPAC-NED <dcook(a)ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S250207bg-3-Initial sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 7591 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250207bg/3 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250207bg/3/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| |WISEA J153919.63+190427.7| 234.83187| 19.07453| G| 530.26| null| null| null| 13.627| 0.172| 10.078| 0.006|5.48e-07| 2.24e-09| |WISEA J152319.42+240611.6| 230.83105| 24.10320| G| 663.87| 0.16| null| null| 14.431| 0.157| 10.454| 0.006|3.80e-07| 1.72e-09| |WISEA J154012.34+184306.0| 235.05140| 18.71817| G| 417.30| 0.08| null| null| 13.309| 0.160| 9.114| 0.005|2.45e-07| 1.51e-09| |WISEA J153645.35+185715.6| 234.18906| 18.95426| G| 614.30| 0.14| null| null| 14.462| 0.165| 11.145| 0.006|6.31e-07| 1.29e-09| |WISEA J150631.38+283419.0| 226.63079| 28.57192| G| 515.26| 0.04| null| null| 13.286| 0.172| 10.718| 0.006|5.69e-07| 1.21e-09| |WISEA J155025.85+130154.2| 237.60767| 13.03173| G| 581.25| 0.10| null| null| 13.459| 0.155| 10.806| 0.006|4.18e-07| 1.05e-09| |WISEA J151550.70+275958.5| 228.96137| 27.99951| G| 504.04| 0.05| 20.968| 0.139| 13.749| 0.153| 10.538| 0.006|3.27e-07| 7.89e-10| | [HB89] 1552+085| 238.68574| 8.37263| QSO| 557.07| 0.06| 17.225| 0.024| 12.724| 0.045| 11.383| 0.023|5.56e-07| 7.54e-10| |WISEA J151458.01+273639.7| 228.74172| 27.61105| G| 560.27| 0.21| 22.052| 0.306| 11.568| 0.117| 11.617| 0.007|6.48e-07| 7.15e-10| |WISEA J155856.52+032444.3| 239.73542| 3.41238| G| 408.76| 0.10| null| null| 12.955| 0.169| 10.037| 0.006|2.71e-07| 6.96e-10| |WISEA J153250.52+200718.3| 233.21046| 20.12169| G| 681.89| 0.13| null| null| 13.831| 0.187| 10.888| 0.006|1.99e-07| 6.42e-10| | 3C 327| 240.61406| 1.96560| G| 486.72| 2.15| 20.654| 0.174| 12.897| 0.047| 11.037| 0.006|4.26e-07| 6.11e-10| |WISEA J155639.59+111348.0| 239.16499| 11.22994| G| 486.41| 0.14| null| null| 14.133| 0.119| 9.442| 0.006|9.76e-08| 6.04e-10| |WISEA J154320.19+143045.0| 235.83416| 14.51254| G| 622.09| 0.04| null| null| 13.890| 0.198| 11.215| 0.006|2.64e-07| 5.21e-10| |WISEA J151556.87+264556.0| 228.98694| 26.76548| G| 592.88| null| null| null| 13.560| 0.139| 12.348| 0.011|8.01e-07| 5.06e-10| |WISEA J145244.45+315248.3| 223.18524| 31.88009| G| 537.68| 0.07| null| null| 12.904| 0.040| 11.775| 0.006|5.42e-07| 4.75e-10| |WISEA J150746.48+284911.8| 226.94359| 28.81997| G| 515.60| 0.75| 20.018| 0.182| 12.395| 0.100| 12.063| 0.007|7.53e-07| 4.66e-10| |WISEA J145519.43+321511.0| 223.83099| 32.25305| G| 538.51| 0.21| null| null| 13.017| 0.046| 11.996| 0.008|5.89e-07| 4.23e-10| |WISEA J145331.46+302133.9| 223.38103| 30.35929| G| 566.40| 0.12| 22.065| 0.341| 14.897| 0.264| 9.870| 0.006|7.14e-08| 4.02e-10| |WISEA J154015.93+175229.2| 235.06642| 17.87478| G| 474.23| null| null| null| 12.689| 0.157| 11.861| 0.007|6.29e-07| 3.97e-10| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S250207bg sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). View this GCN Circular online at https://gcn.nasa.gov/circulars/39206. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37214] Konus-Wind detection of GRB 250204B
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39205 SUBJECT: Konus-Wind detection of GRB 250204B DATE: 25/02/07 15:46:33 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The short-duration GRB 250204B (Fermi-GBM detection: Fermi GBM team, GCN 39141; AstroSat CZTI detection: Dasgupta et al., GCN 39142; IPN triangulation: Svinkin et al., GCN 39145; SVOM/GRM observation: Zhang et al., GCN 39163) triggered Konus-Wind at T0=24073.659 s UT (06:41:13.659). The burst light curve shows a single pulse which starts at ~T0-0.1 s and has a total duration of ~1.5 s. The emission is seen up to ~2 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250204_T24073/ As observed by Konus-Wind, the burst had a fluence of 2.99(-0.29,+0.37)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.008 s, of 7.51(-1.64,+1.74)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.85(-0.17,+0.19) and Ep = 383(-66,+92) keV (chi2 = 16/22 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.1 (chi2 = 16/21 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/39205. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37213] IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39204 SUBJECT: IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate DATE: 25/02/07 14:01:44 GMT FROM: Gianluca Masi at Virtual Telescope Project <gianluca(a)bellatrixobservatory.org> Gianluca Masi (Virtual Telescope Project) reports: Following up LIGO/Virgo/KAGRA S250206dm (LVKC, GCN 39175) at optical wavelengths, we managed to image the field centered at position RA = 149.16, Decl. =-17.94 and covering the complete 0.43 deg. error region reported by the IceCube Collaboration (GCN 39176), remotely using our 250mm-f/4.5 robotic astrograph installed at our facility in Manciano (GR), Italy. We collected 35 x 120s unfiltered exposures under significant moonlight, with a total integration of 70 minutes, centered on 22:53:35 UTC, 06 Feb. 2025, about 1.5 hours after the event. A CMOS camera based on the Sony IMX455 sensor was used. Comparing the resulting image with the POSS2, blue filter, we did not record any obvious new source, down to mag. 19. View this GCN Circular online at https://gcn.nasa.gov/circulars/39204. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37212] IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39203 SUBJECT: IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 25/02/07 13:48:55 GMT FROM: Giacomo Sommani at Ruhr-Universität Bochum <gsommani(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2025-02-07 at 02:07:55.27 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_BRONZE alert stream. The average astrophysical neutrino purity for bronze alerts is 30%. This alert has an estimated false alarm rate of 1.45 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/140472_78196104.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2025-02-07 Time: 02:07:55.27 UT RA: 132.93 (+2.05, -1.89 deg 90% PSF containment) J2000 Dec: 20.66 (+1.28, -1.40 deg 90% PSF containment) J2000 Two Fermi 4FGL or 3FHL catalog sources are in the 90% uncertainty region: 4FGL J0854.8+2006 and 4FGL J0856.8+2056, located 0.9 deg and 1.2 deg away from the best-fit position, respectively. We encourage further follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu View this GCN Circular online at https://gcn.nasa.gov/circulars/39203. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37211] GRB 250207A: REM optical afterglow detection
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39202 SUBJECT: GRB 250207A: REM optical afterglow detection DATE: 25/02/07 13:23:26 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio, M. Ferro, P. D’Avanzo, S. Covino (INAF-OAB), A. Melandri (INAF-OAR), D. B. Malesani (DAWN/NBI and Radboud Univ.), G. Tagliaferri, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 250207A, detected by Fermi/GBM (Fermi GBM Team, GCN 39181) and Swift/BAT (Ferro et al., GCN 39182) with the REM 60cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried in the g, r, i, z, J, H, K bands, starting on 2025 February 07 at 01:17:08 UT (i.e. 61 s after the Swift trigger), and lasting for about 2 hours. From preliminary photometry we detect the counterpart in the optical images at the position of the optical afterglow (Angulo et al., GCN 39186; Kuin & Ferro, GCN 39199) with the following magnitude: r = 12.7 +/- 0.1 (AB; calibrated against the Pan-STARRS catalogue) at a mid-time of t - t0 = 66 s after the trigger. The analysis of the NIR data is ongoing. View this GCN Circular online at https://gcn.nasa.gov/circulars/39202. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37210] LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39201 SUBJECT: LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate DATE: 25/02/07 12:27:19 GMT FROM: Luise Kranzhoff at Maastricht University <luise.kranzhoff(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250207bg during real-time processing of data from LIGO Livingston Observatory (L1) and Virgo Observatory (V1) at 2025-02-07 11:56:45.258 UTC (GPS time: 1422964623.258). The candidate was found by the GstLAL [1] and SPIIR [2] analysis pipelines. S250207bg is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.9e-36 Hz, or about one in 1e28 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250207bg After parameter estimation by RapidPE-RIFT [3], the classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), BNS (<1%), or Terrestrial (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [4] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [4] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 29 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [5], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 110 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 546 +/- 98 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [2] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [3] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [4] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [5] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39201. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37209] LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39200 SUBJECT: LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume DATE: 25/02/07 11:45:22 GMT FROM: Maria Lisa Brozzetti at Università degli Studi di Perugia <marialisa.brozzetti(a)ligo.org> M. L. Brozzetti (UniPG/INFN), G. Dálya (L2IT/EotvosU), G. Greco (INFN), M. Bawaj (UniPG/INFN), T. Matcovich (UniPG/INFN), S. Cutini (INFN) , R. De Pietri (UniPR/INFN), Marica Branchesi (GSSI), Elahe Khalouei(IPM) On behalf of the GLADEnet Team. We analyzed the completeness of the GLADE+ [1] catalog within the 90% credible localization volume of the S250206dm event from the Update-6 alert from the GCN Circular 39175. The completeness value is 5.6e-1 in the B-band using the last released skymap : Bilby.multiorder.fits,1 , which means that the catalogue contains 56% of the total light in the B-band expected from galaxies in the localization volume. A total of 107,012 galaxies are identified within the 90% gravitational volume. The complete list of galaxies can be downloaded from the GLADEnet webpage [2] : https://virgo.pg.infn.it/gladenet/catalogs/ GLADEnet allows for the interactive visualization of the 90% localization area and its intersection with regions of high extinction as defined in GLADE+. Furthermore, the first 1000 galaxies can be explored interactively, enabling users to filter galaxies based on their 3D probability density or their absolute B magnitude. The ligo.skymap cross-match method [3,4] is used to obtain the list of galaxies. References: [1]GLADE+: An Extended Galaxy Catalogue for Multimessenger Searches with Advanced Gravitational-wave Detectors G. Dálya et al. MNRAS, 514,1, pp.1403-1411, 2022 [2] GLADEnet: A progressive web app for multi-messenger cosmology and electromagnetic follow-ups of gravitational-wave sources M. L. Brozzetti, G. Dálya, G. Greco, M. Bawaj, T. Matcovich, M. Branchesi, T. Boch, M. Baumann, S. Cutini, R. De Pietri et al. (4 more) A&A, 684, A44 (2024) [3] Singer, L. P., Chen, H.-Y., Holz, D. E., et al. 2016, Astropys. J. Lett., 829, L15. doi:10.3847/2041-8205/829/1/L15 [4] Singer, L. P., Chen, H.-Y., Holz, D. E., et al. 2016, Astropys. J. Supp., 226, 10. doi:10.3847/0067-0049/226/1/10 View this GCN Circular online at https://gcn.nasa.gov/circulars/39200. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37208] GRB 250207A: Swift/UVOT Detection
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39199 SUBJECT: GRB 250207A: Swift/UVOT Detection DATE: 25/02/07 10:42:24 GMT FROM: Paul Kuin at MSSL <npkuin(a)gmail.com> Paul Kuin (MSSL/UCL) and M. Ferro (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250207A 113 s after the BAT trigger (Ferro et al., GCN Circ. 39182). The source was also reported by Angulo et al. GCN Circ. 39186. The preliminary UVOT position is: RA (J2000) = 01:04:21.39 = 16.08912 (deg.) Dec (J2000) = -12:09:52.5 = -12.16459 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 113 263 147 15.00 +/- 0.02 v 655 674 19 16.89 +/- 0.20 b 581 600 19 16.56 +/- 0.09 u 326 575 246 15.65 +/- 0.03 uvm2 679 699 19 > 17.3 (3 sigma UL) uvw2 630 650 19 > 17.6 (3 sigma UL) The lack of detection in the UVM2 band may indicate a redshift greater than 1.3. The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.027 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/39199. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37207] LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
by GCN Circulars 07 Feb '25

07 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39198 SUBJECT: LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate DATE: 25/02/07 10:37:39 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Rosa L. Becerra (U Rome), Alan M. Watson (UNAM), William H. Lee (UNAM), Camila Angulo Valdez (UNAM), Eleonora Troja (U Rome), Nat Butler (ASU), Simone Dichiara (Penn State University), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), Océlotl López (UNAM), and Margarita Pereyra (UNAM) report: As part of the optical follow-up campaign for LIGO/Virgo/KAGRA S250206dm (LVKC, GCN 39175), the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) observed the position RA, Dec = 149.16, -17.94, reported by the IceCube Collaboration as a track-like event spatially and temporally coincident with the gravitational-wave candidate S250206dm (IceCube Collaboration, GCN 39176). DDOTI covered the complete error region reported for this candidate (angular uncertainty of 0.43 deg, IceCube Collaboration, GCN 39176) beginning at 2025-02-07 07:07 UTC (T+9.7 hours after the event). A total exposure of 18 minutes was obtained in the w filter, reaching a 10-sigma limiting magnitude of w = 19.4. Comparing our observations with the USNO-B1 and PanSTARRS PS1 DR2 catalogs, we detect no uncatalogued sources within the observed field to our 10-sigma limit. Observations related to S250206dm are ongoing. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. View this GCN Circular online at https://gcn.nasa.gov/circulars/39198. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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