TITLE: GCN CIRCULAR NUMBER: 41609 SUBJECT: LIGO/Virgo/KAGRA S250830bp GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume DATE: 25/08/30 14:01:52 GMT FROM: Maria Brozzetti at Università degli Studi di Perugia <marialisa.brozzetti@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) On behalf of the GLADEnet Team. We analyzed the completeness of the GLADE+ [1] catalog within the 90% credible localization volume of the S250830bp event from the 4-Update alert from the GCN Circular 41606. The completeness value is 6.6e-1 in the B-band using the last released skymap : [Bilby.multiorder.fits,0](https://gracedb.ligo.org/api/superevents/S250830bp/files/Bilby.multiorder.fi...), which means that the catalogue contains 66% of the total light in the B-band expected from galaxies in the localization volume. A total of 517 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/](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/41609. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...