GW231123: A Binary Black Hole Merger with Total Mass 190–265 M⊙

Abac, A. G.; Abouelfettouh, I.; Acernese, F.; Ackley, K.; Adamcewicz, C.; Adhicary, S.; Adhikari, D.; Adhikari, N.; Adhikari, R. X.; Adkins, V. K.; Afroz, S.; Agapito, A.; Agarwal, D.; Agathos, M.; Aggarwal, N.; Aggarwal, S.; Aguiar, O. D.; Ahrend, I.-L.; Aiello, L.; Ain, A.; Ajith, P.; Akutsu, T.; Albanesi, S.; Ali, W.; Al-Kershi, S.; Alléné, C.; Allocca, A.; Al-Shammari, S.; Altin, P. A.; Alvarez-Lopez, S.; Amar, W.; Amarasinghe, O.; Amato, A.; Amicucci, F.; Amra, C.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Andia, M.; Ando, M.; Andrés-Carcasona, M.; Andrić, T.; Anglin, J.; Ansoldi, S.; Antelis, J. M.; Antier, S.; Aoumi, M.; Appavuravther, E. Z.; Appert, S.; Apple, S. K.; Arai, K.; Araujo Alvarez, C.; Araya, A.; Araya, M. C.; Arca Sedda, M.; Areeda, J. S.; Aritomi, N.; Armato, F.; Armstrong, S.; Arnaud, N.; Arogeti, M.; Aronson, S. M.; Arun, K. G.; Ashton, G.; Aso, Y.; Asprea, L.; Assiduo, M.; Assis de Souza Melo, S.; Aston, S. M.; Astone, P.; Attadio, F.; Aubin, F.; AultONeal, K.; Avallone, G.; Avila, E. A.; Babak, S.; Badger, C.; Bae, S.; Bagnasco, S.; Baiotti, L.; Bajpai, R.; Baka, T.; Baker, A. M.; Baker, K. A.; Baker, T.; Baldi, G.; Baldicchi, N.; Ball, M.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Banerjee, B.; Bankar, D.; Baptiste, T. M.; Baral, P.; Baratti, M.; Barayoga, J. C.; Barish, B. C.; Barker, D.; Barman, N.; Barneo, P.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartoletti, A. M.; Barton, M. A.; Bartos, I.; Basalaev, A.; Bassiri, R.; Basti, A.; Bawaj, M.; Baxi, P.; Bayley, J. C.; Baylor, A. C.; Baynard II, P. A.; Bazzan, M.; Bedakihale, V. M.; Beirnaert, F.; Bejger, M.; Belardinelli, D.; Bell, A. S.; Bellie, D. S.; Bellizzi, L.; Benoit, W.; Bentara, I.; Bentley, J. D.; Ben Yaala, M.; Bera, S.; Bergamin, F.; Berger, B. K.; Bernuzzi, S.; Beroiz, M.; Berry, C. P. L.; Bersanetti, D.; Bertheas, T.; Bertolini, A.; Betzwieser, J.; Beveridge, D.; Bevilacqua, G.; Bevins, N.; Bhandare, R.; Bhatt, R.; Bhattacharjee, D.; Bhattacharyya, S.; Bhaumik, S.; Bhagwat, S.; Biancalana, V.; Bianchi, A.; Bilenko, I. A.; Billingsley, G.; Binetti, A.; Bini, S.; Binu, C.; Biot, S.; Birnholtz, O.; Biscoveanu, S.; Bisht, A.; Bitossi, M.; Bizouard, M.-A.; Blaber, S.; Blackburn, J. K.; Blagg, L. A.; Blair, C. D.; Blair, D. G.; Bode, N.; Boettner, N.; Boileau, G.; Boldrini, M.; Bolingbroke, G. N.; Bolliand, A.; Bonavena, L. D.; Bondarescu, R.; Bondu, F.; Bonilla, E.; Bonilla, M. S.; Bonino, A.; Bonnand, R.; Borchers, A.; Borhanian, S.; Boschi, V.; Bose, S.; Bossilkov, V.; Bothra, Y.; Boudon, A.; Bourg, L.; Boyle, M.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Branch, A.; Branchesi, M.; Braun, I.; Briant, T.; Brillet, A.; Brinkmann, M.; Brockill, P.; Brockmueller, E.; Brooks, A. F.; Brown, B. C.; Brown, D. D.; Brozzetti, M. L.; Brunett, S.; Bruno, G.; Bruntz, R.; Bryant, J.; Bu, Y.; Bucci, F.; Buchanan, J.; Bulashenko, O.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burtnyk, K.; Buscicchio, R.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabourn Davies, G. S.; Cabrita, R.; Cáceres-Barbosa, V.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calafat, A.; Calderón Bustillo, J.; Callister, T. A.; Calloni, E.; Callos, S. R.; Canepa, M.; Caneva Santoro, G.; Cannon, K. C.; Cao, H.; Capistran, L. A.; Capocasa, E.; Capote, E.; Capurri, G.; Carapella, G.; Carbognani, F.; Carlassara, M.; Carlin, J. B.; Carlson, T. K.; Carney, M. F.; Carpinelli, M.; Carrillo, G.; Carter, J. J.; Carullo, G.; Casallas-Lagos, A.; Casanueva Diaz, J.; Casentini, C.; Castro-Lucas, S. Y.; Caudill, S.; Cavaglià, M.; Cavalieri, R.; Ceja, A.; Cella, G.; Cerdá-Durán, P.; Cesarini, E.; Chabbra, N.; Chaibi, W.; Chakraborty, A.; Chakraborty, P.; Chakraborty, S.; Chalathadka Subrahmanya, S.; Chan, J. C. L.; Chan, M.; Chandra, K.; Chang, K.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chatterjee, C.; Chatterjee, Debarati; Chatterjee, Deep; Chaturvedi, M.; Chaty, S.; Chatziioannou, K.; Chen, A.; Chen, A. H.-Y.; Chen, D.; Chen, H.; Chen, H. Y.; Chen, S.; Chen, Yanbei; Chen, Yitian; Cheng, H. P.; Chessa, P.; Cheung, H. T.; Cheung, S. Y.; Chiadini, F.; Chiarini, G.; Chiba, A.; Chincarini, A.; Chiofalo, M. L.; Chiummo, A.; Chou, C.; Choudhary, S.; Christensen, N.; Chua, S. S. Y.; Ciani, G.; Ciecielag, P.; Cieślar, M.; Cifaldi, M.; Cirok, B.; Clara, F.; Clark, J. A.; Clarke, T. A.; Clearwater, P.; Clesse, S.; Cleva, F.; Coccia, E.; Codazzo, E.; Cohadon, P.-F.; Colace, S.; Colangeli, E.; Colleoni, M.; Collette, C. G.; Collins, J.; Colloms, S.; Colombo, A.; Compton, C. M.; Connolly, G.; Conti, L.; Corbitt, T. R.; Cordero-Carrión, I.; Corezzi, S.; Cornish, N. J.; Coronado, I.; Corsi, A.; Cottingham, R.; Coughlin, M. W.; Couineaux, A.; Couvares, P.; Coward, D. M.; Coyne, R.; Cozzumbo, A.; Creighton, J. D. E.; Creighton, T. D.; Cremonese, P.; Crook, S.; Crouch, R.; Csizmazia, J.; Cudell, J. R.; Cullen, T. J.; Cumming, A.; Cuoco, E.; Cusinato, M.; Da Conceição, L. V.; Dal Canton, T.; Dal Pra, S.; Dálya, G.; D'Angelo, B.; Danilishin, S.; D'Antonio, S.; Danzmann, K.; Darroch, K. E.; Dartez, L. P.; Das, R.; Dasgupta, A.; Dattilo, V.; Daumas, A.; Davari, N.; Dave, I.; Davenport, A.; Davier, M.; Davies, T. F.; Davis, D.; Davis, L.; Davis, M. C.; Davis, P.; Daw, E. J.; Dax, M.; De Bolle, J.; Deenadayalan, M.; Degallaix, J.; De Laurentis, M.; De Lillo, F.; Della Torre, S.; Del Pozzo, W.; Demagny, A.; De Marco, F.; Demasi, G.; De Matteis, F.; Demos, N.; Dent, T.; Depasse, A.; DePergola, N.; De Pietri, R.; De Rosa, R.; De Rossi, C.; Desai, M.; DeSalvo, R.; DeSimone, A.; De Simone, R.; Dhani, A.; Diab, R.; Díaz, M. C.; Di Cesare, M.; Dideron, G.; Dietrich, T.; Di Fiore, L.; Di Fronzo, C.; Di Giovanni, M.; Di Girolamo, T.; Diksha, D.; Ding, J.; Di Pace, S.; Di Palma, I.; Di Piero, D.; Di Renzo, F.; Divyajyoti; Dmitriev, A.; Docherty, J. P.; Doctor, Z.; Doerksen, N.; Dohmen, E.; Doke, A.; Domiciano De Souza, A.; D'Onofrio, L.; Donovan, F.; Dooley, K. L.; Dooney, T.; Doravari, S.; Dorosh, O.; Doyle, W. J. D.; Drago, M.; Driggers, J. C.; Dunn, L.; Dupletsa, U.; Duverne, P.-A.; D'Urso, D.; Dutta Roy, P.; Duval, H.; Dwyer, S. E.; Eassa, C.; Ebersold, M.; Eckhardt, T.; Eddolls, G.; Effler, A.; Eichholz, J.; Einsle, H.; Eisenmann, M.; Emma, M.; Endo, K.; Enficiaud, R.; Errico, L.; Espinosa, R.; Esposito, M.; Essick, R. C.; Estellés, H.; Etzel, T.; Evans, M.; Evstafyeva, T.; Ewing, B. E.; Ezquiaga, J. M.; Fabrizi, F.; Fafone, V.; Fairhurst, S.; Farah, A. M.; Farr, B.; Farr, W. M.; Favaro, G.; Favata, M.; Fays, M.; Fazio, M.; Feicht, J.; Fejer, M. M.; Felicetti, R.; Fenyvesi, E.; Fernandes, J.; Fernandes, T.; Fernando, D.; Ferraiuolo, S.; Ferreira, T. A.; Fidecaro, F.; Figura, P.; Fiori, A.; Fiori, I.; Fisher, R. P.; Fittipaldi, R.; Fiumara, V.; Flaminio, R.; Fleischer, S. M.; Fleming, L. S.; Floden, E.; Fong, H.; Font, J. A.; Fontinele-Nunes, F.; Foo, C.; Fornal, B.; Franceschetti, K.; Franchini, N.; Frappez, F.; Frasca, S.; Frasconi, F.; Freed, J. P.; Frei, Z.; Freise, A.; Freitas, O.; Frey, R.; Frischhertz, W.; Fritschel, P.; Frolov, V. V.; Fronzé, G. G.; Fuentes-Garcia, M.; Fujii, S.; Fujimori, T.; Fulda, P.; Fyffe, M.; Gadre, B.; Gair, J. R.; Galaudage, S.; Galdi, V.; Gamba, R.; Gamboa, A.; Gamoji, S.; Ganapathy, D.; Ganguly, A.; Garaventa, B.; García-Bellido, J.; García-Quirós, C.; Gardner, J. W.; Gardner, K. A.; Garg, S.; Gargiulo, J.; Garrido, X.; Garron, A.; Garufi, F.; Garver, P. A.; Gasbarra, C.; Gateley, B.; Gautier, F.; Gayathri, V.; Gayer, T.; Gemme, G.; Gennai, A.; Gennari, V.; George, J.; George, R.; Gerberding, O.; Gergely, L.; Ghosh, Sayantan; Ghosh, Shaon; Ghosh, Shrobana; Ghosh, Suprovo; Ghosh, Tathagata; Giaime, J. A.; Giardina, K. D.; Gibson, D. R.; Gier, C.; Gkaitatzis, S.; Glanzer, J.; Glotin, F.; Godfrey, J.; Godley, R. V.; Godwin, P.; Goettel, A. S.; Goetz, E.; Golomb, J.; Gomez Lopez, S.; Goncharov, B.; González, G.; Goodarzi, P.; Goode, S.; Gosselin, M.; Gouaty, R.; Gould, D. W.; Govorkova, K.; Grado, A.; Graham, V.; Granados, A. E.; Granata, M.; Granata, V.; Gras, S.; Grassia, P.; Graves, J.; Gray, C.; Gray, R.; Greco, G.; Green, A. C.; Green, L.; Green, S. M.; Green, S. R.; Greenberg, C.; Gretarsson, A. M.; Griffin, H. K.; Griffith, D.; Griggs, H. L.; Grignani, G.; Grimaud, C.; Grote, H.; Grunewald, S.; Guerra, D.; Guetta, D.; Guidi, G. M.; Guimaraes, A. R.; Gulati, H. K.; Gulminelli, F.; Guo, H.; Guo, W.; Guo, Y.; Gupta, Anuradha; Gupta, I.; Gupta, N. C.; Gupta, S. K.; Gupta, V.; Gupte, N.; Gurs, J.; Gutierrez, N.; Guttman, N.; Guzman, F.; Haba, D.; Haberland, M.; Haino, S.; Hall, E. D.; Hamilton, E. Z.; Hammond, G.; Haney, M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanselman, A. G.; Hansen, H.; Hanson, J.; Hanumasagar, S.; Harada, R.; Hardison, A. R.; Harikumar, S.; Haris, K.; Harley-Trochimczyk, I.; Harmark, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, J.; Haskell, B.; Haster, C. J.; Haughian, K.; Hayakawa, H.; Hayama, K.; Heintze, M. C.; Heinze, J.; Heinzel, J.; Heitmann, H.; Hellman, F.; Helmling-Cornell, A. F.; Hemming, G.; Henderson-Sapir, O.; Hendry, M.; Heng, I. S.; Hennig, M. H.; Henshaw, C.; Heurs, M.; Hewitt, A. L.; Heynen, J.; Heyns, J.; Higginbotham, S.; Hild, S.; Hill, S.; Himemoto, Y.; Hirata, N.; Hirose, C.; Hofman, D.; Hogan, B. E.; Holland, N. A.; Hollows, I. J.; Holz, D. E.; Honet, L.; Horton-Bailey, D. J.; Hough, J.; Hourihane, S.; Howard, N. T.; Howell, E. J.; Hoy, C. G.; Hrishikesh, C. A.; Hsi, P.; Hsieh, H.-F.; Hsieh, H.-Y.; Hsiung, C.; Hsu, S.-H.; Hsu, W.-F.; Hu, Q.; Huang, H. Y.; Huang, Y.; Huang, Y. T.; Huddart, A. D.; Hughey, B.; Hui, V.; Husa, S.; Huxford, R.; Iampieri, L.; Iandolo, G. A.; Ianni, M.; Iannone, G.; Iascau, J.; Ide, K.; Iden, R.; Ierardi, A.; Ikeda, S.; Imafuku, H.; Inoue, Y.; Iorio, G.; Iosif, P.; Iqbal, M. H.; Irwin, J.; Ishikawa, R.; Isi, M.; Isleif, K. S.; Itoh, Y.; Iwaya, M.; Iyer, B. R.; Jacquet, C.; Jacquet, P.-E.; Jacquot, T.; Jadhav, S. J.; Jadhav, S. P.; Jain, M.; Jain, T.; James, A. L.; Jani, K.; Janthalur, N. N.; Jaraba, S.; Jaranowski, P.; Jaume, R.; Javed, W.; Jennings, A.; Jensen, M.; Jia, W.; Jiang, J.; Jin, H.-B.; Johns, G. R.; Johnson, N. A.; Johnson-McDaniel, N. K.; Johnston, M. C.; Johnston, R.; Johny, N.; Jones, D. H.; Jones, D. I.; Jones, R.; Jose, H. E.; Joshi, P.; Joshi, S. K.; Joubert, G.; Ju, J.; Ju, L.; Jung, K.; Junker, J.; Juste, V.; Kabagoz, H. B.; Kajita, T.; Kaku, I.; Kalogera, V.; Kalomenopoulos, M.; Kamiizumi, M.; Kanda, N.; Kandhasamy, S.; Kang, G.; Kannachel, N. C.; Kanner, J. B.; KantiMahanty, S. A.; Kapadia, S. J.; Kapasi, D. P.; Karthikeyan, M.; Kasprzack, M.; Kato, H.; Kato, T.; Katsavounidis, E.; Katzman, W.; Kaushik, R.; Kawabe, K.; Kawamoto, R.; Keitel, D.; Kemperman, L. J.; Kennington, J.; Kerkow, F. A.; Kesharwani, R.; Key, J. S.; Khadela, R.; Khadka, S.; Khadkikar, S. S.; Khalili, F. Y.; Khan, F.; Khanam, T.; Khursheed, M.; Khusid, N. M.; Kiendrebeogo, W.; Kijbunchoo, N.; Kim, C.; Kim, J. C.; Kim, K.; Kim, M. H.; Kim, S.; Kim, Y.-M.; Kimball, C.; Kimes, K.; Kinnear, M.; Kissel, J. S.; Klimenko, S.; Knee, A. M.; Knox, E. J.; Knust, N.; Kobayashi, K.; Koehlenbeck, S. M.; Koekoek, G.; Kohri, K.; Kokeyama, K.; Koley, S.; Kolitsidou, P.; Koloniari, A. E.; Komori, K.; Kong, A. K. H.; Kontos, A.; Koponen, L. M.; Korobko, M.; Kou, X.; Koushik, A.; Kouvatsos, N.; Kovalam, M.; Koyama, T.; Kozak, D. B.; Kranzhoff, S. L.; Kringel, V.; Krishnendu, N. V.; Kroker, S.; Królak, A.; Kruska, K.; Kubisz, J.; Kuehn, G.; Kulkarni, S.; Kulur Ramamohan, A.; Kumar, Achal; Kumar, Anil; Kumar, Praveen; Kumar, Prayush; Kumar, Rahul; Kumar, Rakesh; Kume, J.; Kuns, K.; Kuntimaddi, N.; Kuroyanagi, S.; Kuwahara, S.; Kwak, K.; Kwan, K.; Kwon, S.; Lacaille, G.; Laghi, D.; Laity, A. H.; Lalande, E.; Lalleman, M.; Lalremruati, P. C.; Landry, M.; Lane, B. B.; Lang, R. N.; Lange, J.; Langgin, R.; Lantz, B.; L. Rosa, I.; Larsen, J.; Lartaux-Vollard, A.; Lasky, P. D.; Lawrence, J.; Laxen, M.; Lazarte, C.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leali, L.; Lecoeuche, Y. K.; Lee, H. M.; Lee, H. W.; Lee, J.; Lee, K.; Lee, R.-K.; Lee, R.; Lee, Sungho; Lee, Sunjae; Lee, Y.; Legred, I. N.; Lehmann, J.; Lehner, L.; Le Jean, M.; Lematre, A.; Lenti, M.; Leonardi, M.; Lequime, M.; Leroy, N.; Lesovsky, M.; Letendre, N.; Lethuillier, M.; Levin, Y.; Leyde, K.; Li, A. K. Y.; Li, K. L.; Li, X.; Li, Y.; Li, Z.; Lihos, A.; Lin, E. T.; Lin, F.; Lin, L. C.-C.; Lin, Y.-C.; Lindsay, C.; Linker, S. D.; Liu, A.; Liu, G. C.; Liu, Jian; Llamas Villarreal, F.; Llobera-Querol, J.; Lo, R. K. L.; Locquet, J.-P.; Loggins, S. C. G.; Loizou, M. R.; London, L. T.; Longo, A.; Lopez, D.; Lopez Portilla, M.; Lorenzini, M.; Lorenzo-Medina, A.; Loriette, V.; Lormand, M.; Losurdo, G.; Lotti, E.; Lott IV, T. P.; Lough, J. D.; Loughlin, H. A.; Lousto, C. O.; Low, N.; Lu, N.; Lucchesi, L.; Lück, H.; Lumaca, D.; Lundgren, A. P.; Lussier, A. W.; Macas, R.; MacInnis, M.; Macleod, D. M.; MacMillan, I. A. O.; Macquet, A.; Maeda, K.; Maenaut, S.; Magare, S. S.; Magee, R. M.; Maggio, E.; Maggiore, R.; Magnozzi, M.; Mahesh, M.; Maini, M.; Majhi, S.; Majorana, E.; Makarem, C. N.; Malakar, D.; Malaquias-Reis, J. A.; Mali, U.; Maliakal, S.; Malik, A.; Mallick, L.; Malz, A.-K.; Man, N.; Mancarella, M.; Mandic, V.; Mangano, V.; Mannix, B.; Mansell, G. L.; Manske, M.; Mantovani, M.; Mapelli, M.; Marinelli, C.; Marion, F.; Markosyan, A. S.; Markowitz, A.; Maros, E.; Marsat, S.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinez, B. B.; Martinez, D. A.; Martinez, M.; Martinez, V.; Martini, A.; Martins, J. C.; Martynov, D. V.; Marx, E. J.; Massaro, L.; Masserot, A.; Masso-Reid, M.; Mastrogiovanni, S.; Matcovich, T.; Matiushechkina, M.; Maurin, L.; Mavalvala, N.; Maxwell, N.; McCarrol, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McEachin, S.; McElhenny, C.; McGhee, G. I.; McGinn, J.; McGowan, K. B. M.; McIver, J.; McLeod, A.; McMahon, I.; McRae, T.; McTeague, R.; Meacher, D.; Meagher, B. N.; Mechum, R.; Meijer, Q.; Melatos, A.; Menoni, C. S.; Mera, F.; Mercer, R. A.; Mereni, L.; Merfeld, K.; Merilh, E. L.; Mérou, J. R.; Merritt, J. D.; Merzougui, M.; Messick, C.; Mestichelli, B.; Meyer-Conde, M.; Meylahn, F.; Mhaske, A.; Miani, A.; Miao, H.; Michel, C.; Michimura, Y.; Middleton, H.; Mihaylov, D. P.; Miller, S. J.; Millhouse, M.; Milotti, E.; Milotti, V.; Minenkov, Y.; Minihan, E. M.; Mir, Ll. M.; Mirasola, L.; Miravet-Tenés, M.; Miritescu, C.-A.; Mishra, A.; Mishra, C.; Mishra, T.; Mitchell, A. L.; Mitchell, J. G.; Mitra, S.; Mitrofanov, V. P.; Mitsuhashi, K.; Mittleman, R.; Miyakawa, O.; Miyoki, S.; Miyoko, A.; Mo, G.; Mobilia, L.; Mohapatra, S. R. P.; Mohite, S. R.; Molina-Ruiz, M.; Mondin, M.; Montani, M.; Moore, C. J.; Moraru, D.; More, A.; More, S.; Moreno, C.; Moreno, E. A.; Moreno, G.; Moreso Serra, A.; Morisaki, S.; Moriwaki, Y.; Morras, G.; Moscatello, A.; Mould, M.; Mours, B.; Mow-Lowry, C. M.; Muccillo, L.; Muciaccia, F.; Mukherjee, D.; Mukherjee, Samanwaya; Mukherjee, Soma; Mukherjee, Subroto; Mukherjee, Suvodip; Mukund, N.; Mullavey, A.; Mullock, H.; Mundi, J.; Mungioli, C. L.; Murakoshi, M.; Murray, P. G.; Nabari, D.; Nadji, S. L.; Nagar, A.; Nagarajan, N.; Nakagaki, K.; Nakamura, K.; Nakano, H.; Nakano, M.; Nanadoumgar-Lacroze, D.; Nandi, D.; Napolano, V.; Narayan, P.; Nardecchia, I.; Narikawa, T.; Narola, H.; Naticchioni, L.; Nayak, R. K.; Negri, L.; Nela, A.; Nelle, C.; Nelson, A.; Nelson, T. J. N.; Nery, M.; Neunzert, A.; Ng, S.; Nguyen Quynh, L.; Nichols, S. A.; Nielsen, A. B.; Nishino, Y.; Nishizawa, A.; Nissanke, S.; Niu, W.; Nocera, F.; Noller, J.; Norman, M.; North, C.; Novak, J.; Nowicki, R.; Nuño Siles, J. F.; Nuttall, L. K.; Obayashi, K.; Oberling, J.; O'Dell, J.; Oelker, E.; Oertel, M.; Oganesyan, G.; O'Hanlon, T.; Ohashi, M.; Ohme, F.; Oliveri, R.; Omer, R.; O'Neal, B.; Onishi, M.; Oohara, K.; O'Reilly, B.; Orselli, M.; O'Shaughnessy, R.; O'Shea, S.; Oshino, S.; Osthelder, C.; Ota, I.; Ottaway, D. J.; Ouzriat, A.; Overmier, H.; Owen, B. J.; Ozaki, R.; Pace, A. E.; Pagano, R.; Page, M. A.; Pai, A.; Paiella, L.; Pal, A.; Pal, S.; Palaia, M. A.; Pálfi, M.; Palma, P. P.; Palomba, C.; Palud, P.; Pan, H.; Pan, J.; Pan, K. C.; Panda, P. K.; Pandey, Shiksha; Pandey, Swadha; Pang, P. T. H.; Pannarale, F.; Pannone, K. A.; Pant, B. C.; Panther, F. H.; Panzeri, M.; Paoletti, F.; Paolone, A.; Papadopoulos, A.; Papalexakis, E. E.; Papalini, L.; Papigkiotis, G.; Paquis, A.; Parisi, A.; Park, B.-J.; Park, J.; Parker, W.; Pascale, G.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passenger, L.; Passuello, D.; Patane, O.; Patel, A. V.; Pathak, D.; Patra, A.; Patricelli, B.; Patterson, B. G.; Paul, K.; Paul, S.; Payne, E.; Pearce, T.; Pedraza, M.; Pele, A.; Peña Arellano, F. E.; Peng, X.; Peng, Y.; Penn, S.; Penuliar, M. D.; Perego, A.; Pereira, Z.; Périgois, C.; Perna, G.; Perreca, A.; Perret, J.; Perriès, S.; Perry, J. W.; Pesios, D.; Peters, S.; Petracca, S.; Petrillo, C.; Pfeiffer, H. P.; Pham, H.; Pham, K. A.; Phukon, K. S.; Phurailatpam, H.; Piarulli, M.; Piccari, L.; Piccinni, O. J.; Pichot, M.; Piendibene, M.; Piergiovanni, F.; Pierini, L.; Pierra, G.; Pierro, V.; Pietrzak, M.; Pillas, M.; Pilo, F.; Pinard, L.; Pinto, I. M.; Pinto, M.; Piotrzkowski, B. J.; Pirello, M.; Pitkin, M. D.; Placidi, A.; Placidi, E.; Planas, M. L.; Plastino, W.; Plunkett, C.; Poggiani, R.; Polini, E.; Pomper, J.; Pompili, L.; Poon, J.; Porcelli, E.; Porter, E. K.; Posnansky, C.; Poulton, R.; Powell, J.; Prabhu, G. S.; Pracchia, M.; Pradhan, B. K.; Pradier, T.; Prajapati, A. K.; Prasai, K.; Prasanna, R.; Prasia, P.; Pratten, G.; Principe, G.; Prodi, G. A.; Prosperi, P.; Prosposito, P.; Providence, A. C.; Puecher, A.; Pullin, J.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quéméner, G.; Quetschke, V.; Quinonez, P. J.; Qutob, N.; Rading, R.; Rainho, I.; Raja, S.; Rajan, C.; Rajbhandari, B.; Ramirez, K. E.; Ramis Vidal, F. 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doi:10.3847/2041-8213/ae0c9c

Published November 1, 2025 | Version Published

Journal Article Open

GW231123: A Binary Black Hole Merger with Total Mass 190–265 M⊙

1. Max Planck Institute for Gravitational Physics
2. Laser Interferometer Gravitational Wave Observatory
3. University of Salerno
4. INFN Sezione di Napoli
5. University of Warwick
6. Monash University
7. Pennsylvania State University
8. Leibniz University Hannover
9. University of Wisconsin–Milwaukee
10. California Institute of Technology
11. Louisiana State University
12. Tata Institute of Fundamental Research
13. Centre de Physique Théorique
14. Université Catholique de Louvain
15. Queen Mary University of London
16. University of California, Davis
17. University of Minnesota
18. National Institute for Space Research
19. Astroparticle and Cosmology Laboratory
20. University of Rome Tor Vergata
21. INFN Sezione di Roma II
22. University of Antwerp
23. International Centre for Theoretical Sciences
24. National Astronomical Observatory of Japan
25. Friedrich Schiller University Jena
26. INFN Sezione di Torino
27. INFN Sezione di Genova
28. University of Genoa
29. Université Savoie Mont Blanc
30. University of Naples Federico II
31. Cardiff University
32. Australian National University
33. Massachusetts Institute of Technology
34. Maastricht University
35. National Institute for Subatomic Physics
36. INFN Sezione di Roma I
37. Sapienza University of Rome
38. Institut Fresnel
39. Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
40. University of Tokyo
41. Institute for High Energy Physics
42. Gran Sasso Science Institute
43. Gran Sasso National Laboratory
44. University of Florida
45. University of Udine
46. INFN Sezione di Trieste
47. Monterrey Institute of Technology and Higher Education
48. INFN Sezione di Perugia
49. University of Camerino
50. University of Washington
51. University of Santiago de Compostela
52. California State University, Fullerton
53. University of Strathclyde
54. Claude Bernard University Lyon 1
55. Georgia Institute of Technology
56. Chennai Mathematical Institute
57. Royal Holloway University of London
58. The Graduate University for Advanced Studies, SOKENDAI
59. University of Urbino
60. INFN Sezione di Firenze
61. European Gravitational Observatory
62. University of Strasbourg
63. Embry–Riddle Aeronautical University
64. King's College London
65. Korea Institute of Science & Technology Information
66. Osaka University
67. High Energy Accelerator Research Organization
68. Utrecht University
69. University of Western Australia
70. University of Portsmouth
71. University of Trento
72. Trento Institute for Fundamental Physics and Applications
73. University of Perugia
74. University of Oregon
75. Syracuse University
76. Inter-University Centre for Astronomy and Astrophysics
77. INFN Sezione di Pisa
78. University of Pisa
79. University of Barcelona
80. Institut d'Estudis Espacials de Catalunya
81. University of Glasgow
82. Wigner Research Centre for Physics
83. Concordia University Wisconsin
84. Stanford University
85. University of Michigan–Ann Arbor
86. University of Padua
87. INFN Sezione di Padova
88. Institute for Plasma Research
89. Ghent University
90. Polish Academy of Sciences
91. Northwestern University
92. Universität Hamburg
93. University of the Balearic Islands
94. Laboratoire des 2 Infinis—Toulouse (L2IT-IN2P3), F-31062 Toulouse Cedex 9, France
95. University of Siena
96. Villanova University
97. Raja Ramanna Centre for Advanced Technology
98. Kenyon College
99. Missouri University of Science and Technology
100. Indian Institute of Technology Madras
101. University of Birmingham
102. VU Amsterdam
103. Lomonosov Moscow State University
104. KU Leuven
105. Rochester Institute of Technology
106. Université Libre de Bruxelles
107. Bar-Ilan University
108. Observatoire de la Côte d'Azur
109. University of British Columbia
110. University of Adelaide
111. French National Centre for Scientific Research
112. University of Rennes 1
113. Washington State University
114. Cornell University
115. Kastler-Brossel Laboratory
116. Christopher Newport University
117. University of Melbourne
118. University of Warsaw
119. University of Maryland, College Park
120. University of Milano-Bicocca
121. INFN Sezione di Milano Bicocca
122. Institut Lumière Matière
123. University of Chicago
124. University of Arizona
125. University of Massachusetts Dartmouth
126. University of Copenhagen
127. University of Guadalajara
128. Institute for Space Astrophysics and Planetology
129. Colorado State University
130. University of Valencia
131. National Central University
132. National Tsing Hua University
133. Charles Sturt University
134. Vanderbilt University
135. National Chiao Tung University
136. The University of Texas at Austin
137. Northeastern University
138. University of Toyama
139. Carleton College
140. University of Szeged
141. ARC Centre of Excellence for Gravitational Wave Discovery
142. University of Cagliari
143. Brera Astronomical Observatory
144. Montana State University
145. University of Utah
146. Johns Hopkins University
147. University of Rhode Island
148. The University of Texas Rio Grande Valley
149. University of Liège
150. University of Bologna
151. INFN Sezione di Bologna
152. University of Manitoba
153. INFN-CNAF—Bologna, Viale Carlo Berti Pichat, 6/2, 40127 Bologna BO, Italy
154. University of Sassari
155. Laboratori Nazionali del Sud
156. Laboratoire de Physique Corpusculaire de Caen
157. University of Sheffield
158. University of Florence
159. University of Parma
160. INFN, Sezione di Milano Bicocca, Gruppo Collegato di Parma, I-43124 Parma, Italy
161. California State University, Long Beach
162. Marquette University
163. Perimeter Institute
164. Mines ParisTech
165. University of Trieste
166. National Centre for Nuclear Research
167. Vrije Universiteit Brussel
168. University of Zurich
169. Canadian Institute for Theoretical Astrophysics
170. Stony Brook University
171. Center for Computational Astrophysics, Flatiron Institute, New York, NY 10010, USA
172. Montclair State University
173. Institute for Nuclear Research
174. Indian Institute of Technology Bombay
175. University of Minho
176. Center for Particle Physics of Marseilles
177. Superconducting and other Innovative Materials and Devices Institute
178. University of Basilicata
179. Western Washington University
180. University of the West of Scotland
181. Barry University
182. University of Lisbon
183. Eötvös Loránd University
184. Department of Physics, Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto-cho, Sumiyoshi-ku, Osaka City, Osaka 558-8585, Japan
185. University of Sannio
186. University of California, Berkeley
187. Institute for Theoretical Physics
188. Laboratoire d'Acoustique de l'Université du Mans, UMR CNRS 6613, F-72085 L. Mans, France
189. University of Southampton
190. University of California, Riverside
191. Roma Tre University
192. University of Nevada, Las Vegas, Las Vegas, NV 89154, USA
193. University of Nottingham
194. Ariel University
195. University of Mississippi
196. Graduate School of Science, Institute of Science Tokyo, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
197. Academia Sinica
198. American University
199. University of Milan
200. INFN Sezione di Milano
201. Fukuoka University
202. University of Cambridge
203. Lancaster University
204. Nihon University
205. Niigata University
206. Tamkang University
207. Rutherford Appleton Laboratory
208. Aoyama Gakuin University
209. Helmut Schmidt University
210. Nambu Yoichiro Institute of Theoretical and Experimental Physics (NITEP), Osaka Metropolitan University, 3-3-138 Sugimoto-cho, Sumiyoshi-ku, Osaka City, Osaka 558-8585, Japan
211. Department of Atomic Energy
212. Observatory of Strasbourg
213. University of Białystok
214. National Astronomical Observatories
215. University of Chinese Academy of Sciences
216. Sungkyunkwan University
217. Ulsan National Institute of Science and Technology
218. Chung-Ang University
219. University of Washington Bothell, Bothell, WA 98011, USA
220. University of Ouagadougou
221. Ewha Womans University
222. National Institute for Mathematical Sciences
223. Korea Astronomy and Space Science Institute
224. Chungnam National University
225. Nagoya University
226. Aristotle University of Thessaloniki
227. Bard College
228. Technische Universität Braunschweig
229. Institute of Mathematics
230. Jagiellonian University
231. University of Montreal
232. Indian Institute of Science Education and Research Kolkata
233. Seoul National University
234. Inje University
235. National Cheng Kung University
236. Chinese University of Hong Kong
237. St. Thomas University
238. Scuola Normale Superiore di Pisa
239. Institució Catalana de Recerca i Estudis Avançats
240. Heidelberg University
241. Tokyo City University
242. Tsinghua University
243. Institut des Hautes Études Scientifiques
244. Ryukoku University
245. University of Stavanger
246. Hiroshima University
247. University of Amsterdam
248. University College London
249. Paris Observatory
250. Laboratory Universe and Theories
251. University of Maryland, Baltimore County
252. CSIR—Central Glass and Ceramic Research Institute, Kolkata, West Bengal 700032, India
253. Institute for Complex Systems
254. Yonsei University
255. Hobart and William Smith Colleges
256. Osservatorio Astronomico di Padova
257. Enrico Fermi Center for Study and Research
258. Kennesaw State University
259. Laboratoire de Physique Subatomique et des Technologies Associées
260. University of Antioquia
261. Technical University of Madrid
262. National Institute of Technology
263. Trinity College
264. University of Ferrara
265. Toho University
266. Indian Institute of Technology Gandhinagar
267. Peking University
268. Laboratoire MSME, Cité Descartes, 5 Boulevard Descartes, Champs-sur-Marne, 77454 Marne-la-Vallée Cedex 2, France
269. Osaka Institute of Technology
270. Goddard Space Flight Center
271. Kōchi University
272. Laboratoire de Physique de l'ENS de Lyon
273. Deceased, 2024 September.
274. Kyoto University
275. University of Catania
276. National Defense Academy of Japan
277. Eindhoven University of Technology
278. Beijing Normal University
279. Wuhan University

On 2023 November 23, the two LIGO observatories both detected GW231123, a gravitational-wave signal consistent with the merger of two black holes with masses 137_(−18)^(+23) M⊙ and 101_(−50)+^(+22) M⊙ (90% credible intervals), at a luminosity distance of 0.7–4.1 Gpc, a redshift of 0.40_(−0.25)^(+0.27), and with a network signal-to-noise ratio of ∼20.7. Both black holes exhibit high spins— 0.90_(−0.19)^(+0.10) and 0.80_(−0.52)^(+0.20), respectively. A massive black hole remnant is supported by an independent ringdown analysis. Some properties of GW231123 are subject to large systematic uncertainties, as indicated by differences in the inferred parameters between signal models. The primary black hole lies within or above the theorized mass gap where black holes between 60–130 M⊙ should be rare, due to pair-instability mechanisms, while the secondary spans the gap. The observation of GW231123 therefore suggests the formation of black holes from channels beyond standard stellar collapse and that intermediate-mass black holes of mass ∼200 M⊙ form through gravitational-wave-driven mergers.

Copyright and License

© 2025. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

Strain data from the LIGO detectors associated with GW231123 are available from the Gravitational Wave Open Science Center.³²² Samples from posterior distributions of the source parameters, additional materials, and notebooks for reproducing the figures are available on Zenodo (The LIGO Scientific Collaboration et al. 2025a). The software packages used in our analyses are open source.

This material is based upon work supported by NSF’s LIGO Laboratory, which is a major facility fully funded by the National Science Foundation. The authors also gratefully acknowledge the support of the Science and Technology Facilities Council (STFC) of the United Kingdom, the Max-Planck-Society (MPS), and the State of Niedersachsen/Germany for support for the construction of Advanced LIGO and the construction and operation of the GEO 600 detector. Additional support for Advanced LIGO was provided by the Australian Research Council. The authors gratefully acknowledge the Italian Istituto Nazionale di Fisica Nucleare (INFN), the French Centre National de la Recherche Scientifique (CNRS), and the Netherlands Organization for Scientific Research (NWO) for the construction and operation of the Virgo detector and the creation of and support for the EGO consortium. The authors also gratefully acknowledge research support from these agencies as well as by the Council of Scientific and Industrial Research of India, the Department of Science and Technology, India, the Science & Engineering Research Board (SERB), India, the Ministry of Human Resource Development, India, the Spanish Agencia Estatal de Investigación (AEI), the Spanish Ministerio de Ciencia, Innovación y Universidades, the European Union NextGenerationEU/PRTR (PRTR-C17.I1), the ICSC—Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, funded by the European Union NextGenerationEU, the Comunitat Autonòma de les Illes Balears through the Conselleria d’Educació i Universitats, the Conselleria d’Innovació, Universitats, Ciència i Societat Digital de la Generalitat Valenciana and the CERCA Programme Generalitat de Catalunya, Spain, the Polish National Agency for Academic Exchange, the National Science Centre of Poland and the European Union—European Regional Development Fund; the Foundation for Polish Science (FNP), the Polish Ministry of Science and Higher Education, the Swiss National Science Foundation (SNSF), the Russian Science Foundation, the European Commission, the European Social Funds (ESF), the European Regional Development Funds (ERDF), the Royal Society, the Scottish Funding Council, the Scottish Universities Physics Alliance, the Hungarian Scientific Research Fund (OTKA), the French Lyon Institute of Origins (LIO), the Belgian Fonds de la Recherche Scientifique (FRS-FNRS), Actions de Recherche Concertées (ARC) and Fonds Wetenschappelijk Onderzoek—Vlaanderen (FWO), Belgium, the Paris Île-de-France Region, the National Research, Development and Innovation Office of Hungary (NKFIH), the National Research Foundation of Korea, the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI), the Brazilian Ministry of Science, Technology, and Innovations, the International Center for Theoretical Physics South American Institute for Fundamental Research (ICTP-SAIFR), the Research Grants Council of Hong Kong, the National Natural Science Foundation of China (NSFC), the Israel Science Foundation (ISF), the US–Israel Binational Science Fund (BSF), the Leverhulme Trust, the Research Corporation, the National Science and Technology Council (NSTC), Taiwan, the United States Department of Energy, and the Kavli Foundation. The authors gratefully acknowledge the support of the NSF, STFC, INFN, and CNRS for the provision of computational resources.

This work was supported by MEXT, the JSPS Leading-edge Research Infrastructure Program, JSPS Grant-in-Aid for Specially Promoted Research 26000005, JSPS Grant-in-Aid for Scientific Research on Innovative Areas 2402: 24103006, 24103005, and 2905: JP17H06358, JP17H06361, and JP17H06364, JSPS Core-to-Core Program A: Advanced Research Networks, JSPS Grants-in-Aid for Scientific Research (S) 17H06133 and 20H05639, JSPS Grant-in-Aid for Transformative Research Areas (A) 20A203: JP20H05854, the joint research program of the Institute for Cosmic Ray Research, University of Tokyo, the National Research Foundation (NRF), the Computing Infrastructure Project of the Global Science experimental Data hub Center (GSDC) at KISTI, the Korea Astronomy and Space Science Institute (KASI), the Ministry of Science and ICT (MSIT) in Korea, Academia Sinica (AS), the AS Grid Center (ASGC), and the National Science and Technology Council (NSTC) in Taiwan, under grants including the Science Vanguard Research Program, the Advanced Technology Center (ATC) of NAOJ, and the Mechanical Engineering Center of KEK.

Additional acknowledgments for the support of individual authors may be found in the following document: https://dcc.ligo.org/LIGO-M2300033/public. For the purpose of open access, the authors have applied a Creative Commons Attribution (CC BY) license to any Author Accepted Manuscript version arising. We request that citations of this Letter use “A. G. Abac et al. (LIGO–Virgo–KAGRA Collaboration) ...” or similar phrasing, depending on journal convention.

Software References

The calibration of the LIGO strain data was performed with a GstLAL-based calibration software pipeline (A. Viets et al. 2018). Data quality products and event validation results were computed using the DMT (J. Zweizig 2006), DQR (The LIGO Scientific Collaboration & the Virgo Collaboration 2018), DQSEGDB (R. P. Fisher et al. 2021), gwdetchar (M. Duncan et al. 2021), hveto (J. R. Smith et al. 2011), iDQ (R. Essick et al. 2020), Omicron (F. Robinet et al. 2020), and PythonVirgoTools (The Virgo Collaboration 2021) software packages and contributing software tools. Analyses in this catalog relied on software from the LVK Algorithm Library Suite (The LIGO Scientific Collaboration et al. 2018; K. Wette 2020). The detections of the signals and subsequent significance evaluations were performed with the GstLAL-based inspiral software pipeline (C. Messick et al. 2017; S. Sachdev et al. 2019; C. Hanna et al. 2020; K. Cannon et al. 2021), with the MBTA pipeline (T. Adams et al. 2016; F. Aubin et al. 2021), with the PyCBC (S. A. Usman et al. 2016; A. H. Nitz et al. 2017; G. S. Davies et al. 2020) packages, with the cWB-BBH pipeline (T. Mishra et al. 2025), with cWB-2G (S. Klimenko et al. 2008, 2016; M. Drago et al. 2021), with cWB-XP (S. Klimenko 2022), and with cWB-GMM (V. Gayathri et al. 2020; D. Lopez et al. 2022; L. Smith et al. 2024). Low-latency source localization was performed using BAYESTAR (L. P. Singer & L. R. Price 2016). Estimates of the noise spectra and glitch models were obtained using BayesWave (N. J. Cornish & T. B. Littenberg 2015; T. B. Littenberg & N. J. Cornish 2015; N. J. Cornish et al. 2021). Source parameter estimation was primarily performed with the Bilby and BilbyPipe libraries (G. Ashton et al. 2019; R. J. E. Smith et al. 2020; I. M. Romero-Shaw et al. 2020b), using the Dynesty nested sampling package (J. S. Speagle 2020). The v5PHM waveforms used in parameter estimation were generated using pySEOBNR (D. P. Mihaylov et al. 2025). PESummary was used to postprocess and collate parameter estimation results (C. Hoy & V. Raymond 2021). Some of the parameter estimation analyses were managed with the Asimov library (D. Williams et al. 2023). Ringdown analyses were performed using the pyRing (G. Carullo et al. 2023) library, relying on the CPNest nested sampling algorithm (J. Veitch et al. 2020). The manuscript content has been derived making use of additional publicly available software: matplotlib (J. D. Hunter 2007), numpy (C. R. Harris et al. 2020), scipy (P. Virtanen et al. 2020), seaborn (M. Waskom et al. 2021), and sxs (M. A. Scheel et al. 2025).

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Is new version of: Discussion Paper: arXiv:2507.08219 (arXiv)
Is supplemented by: Dataset: 10.7935/anj7-6q40 (DOI)

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Accepted: 2025-09-26
Available: 2025-10-27

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Caltech groups: Astronomy Department, LIGO, TAPIR, Walter Burke Institute for Theoretical Physics, Division of Physics, Mathematics and Astronomy (PMA)
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GW231123: A Binary Black Hole Merger with Total Mass 190–265 M⊙

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GW231123: A Binary Black Hole Merger with Total Mass 190–265 M⊙

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