All-sky search for long-duration gravitational-wave transients in the first part of the fourth LIGO-Virgo-KAGRA Observing run
This paper presents an all-sky search for long-duration gravitational-wave transients using data from the first part of the LIGO-Virgo-KAGRA fourth observing run (O4a), reporting a 30% average improvement in sensitivity limits over the previous run despite finding no significant detections.
Original authors: The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, A. G. Abac, I. Abouelfettouh, F. Acernese, K. Ackley, C. Adamcewicz, S. Adhicary, D. Adhikari, N. Adhikari, R. X. Adhikari, V. K. Adkins, S. Afroz, A. Agapito, D. Agarwal, M. Agathos, N. Aggarwal, S. Aggarwal, O. D. Aguiar, I. -L. Ahrend, L. Aiello, A. Ain, P. Ajith, T. Akutsu, S. Albanesi, W. Ali, S. Al-Kershi, C. Alléné, A. Allocca, S. Al-Shammari, P. A. Altin, S. Alvarez-Lopez, W. Amar, O. Amarasinghe, A. Amato, F. Amicucci, C. Amra, A. Ananyeva, S. B. Anderson, W. G. Anderson, M. Andia, M. Ando, M. Andrés-Carcasona, T. Andrić, J. Anglin, S. Ansoldi, J. M. Antelis, S. Antier, M. Aoumi, E. Z. Appavuravther, S. Appert, S. K. Apple, K. Arai, A. Araya, M. C. Araya, M. Arca Sedda, J. S. Areeda, N. Aritomi, F. Armato, S. Armstrong, N. Arnaud, M. Arogeti, S. M. Aronson, K. G. Arun, G. Ashton, Y. Aso, L. Asprea, M. Assiduo, S. Assis de Souza Melo, S. M. Aston, P. Astone, F. Attadio, F. Aubin, K. AultONeal, G. Avallone, E. A. Avila, S. Babak, C. Badger, S. Bae, S. Bagnasco, L. Baiotti, R. Bajpai, T. Baka, A. M. Baker, K. A. Baker, T. Baker, G. Baldi, N. Baldicchi, M. Ball, G. Ballardin, S. W. Ballmer, S. Banagiri, B. Banerjee, D. Bankar, T. M. Baptiste, P. Baral, M. Baratti, J. C. Barayoga, B. C. Barish, D. Barker, N. Barman, P. Barneo, F. Barone, B. Barr, L. Barsotti, M. Barsuglia, D. Barta, A. M. Bartoletti, M. A. Barton, I. Bartos, A. Basalaev, R. Bassiri, A. Basti, M. Bawaj, P. Baxi, J. C. Bayley, A. C. Baylor, P. A. Baynard, M. Bazzan, V. M. Bedakihale, F. Beirnaert, M. Bejger, D. Belardinelli, A. S. Bell, D. S. Bellie, L. Bellizzi, W. Benoit, I. Bentara, J. D. Bentley, M. Ben Yaala, S. Bera, F. Bergamin, B. K. Berger, S. Bernuzzi, M. Beroiz, D. Bersanetti, T. Bertheas, A. Bertolini, J. Betzwieser, D. Beveridge, G. Bevilacqua, N. Bevins, R. Bhandare, R. Bhatt, D. Bhattacharjee, S. Bhattacharyya, S. Bhaumik, V. Biancalana, A. Bianchi, I. A. Bilenko, G. Billingsley, A. Binetti, S. Bini, C. Binu, S. Biot, O. Birnholtz, S. Biscoveanu, A. Bisht, M. Bitossi, M. -A. Bizouard, S. Blaber, J. K. Blackburn, L. A. Blagg, C. D. Blair, D. G. Blair, N. Bode, N. Boettner, G. Boileau, M. Boldrini, G. N. Bolingbroke, A. Bolliand, L. D. Bonavena, R. Bondarescu, F. Bondu, E. Bonilla, M. S. Bonilla, A. Bonino, R. Bonnand, A. Borchers, S. Borhanian, V. Boschi, S. Bose, V. Bossilkov, Y. Bothra, A. Boudon, L. Bourg, G. Bouyer, M. Boyle, A. Bozzi, C. Bradaschia, P. R. Brady, A. Branch, M. Branchesi, I. Braun, T. Briant, A. Brillet, M. Brinkmann, P. Brockill, E. Brockmueller, A. F. Brooks, B. C. Brown, D. D. Brown, M. L. Brozzetti, S. Brunett, G. Bruno, R. Bruntz, J. Bryant, Y. Bu, F. Bucci, J. Buchanan, O. Bulashenko, T. Bulik, H. J. Bulten, A. Buonanno, K. Burtnyk, R. Buscicchio, D. Buskulic, C. Buy, R. L. Byer, G. S. Cabourn Davies, R. Cabrita, V. Cáceres-Barbosa, L. Cadonati, G. Cagnoli, C. Cahillane, A. Calafat, T. A. Callister, E. Calloni, S. R. Callos, G. Caneva Santoro, K. C. Cannon, H. Cao, L. A. Capistran, E. Capocasa, E. Capote, G. Capurri, G. Carapella, F. Carbognani, M. Carlassara, J. B. Carlin, T. K. Carlson, M. F. Carney, M. Carpinelli, G. Carrillo, J. J. Carter, G. Carullo, A. Casallas-Lagos, J. Casanueva Diaz, C. Casentini, S. Y. Castro-Lucas, S. Caudill, M. CavagliÃ, R. Cavalieri, A. Ceja, G. Cella, P. Cerdá-Durán, E. Cesarini, N. Chabbra, W. Chaibi, A. Chakraborty, P. Chakraborty, S. Chakraborty, S. Chalathadka Subrahmanya, J. C. L. Chan, M. Chan, K. Chang, S. Chao, P. Charlton, E. Chassande-Mottin, C. Chatterjee, Debarati Chatterjee, Deep Chatterjee, M. Chaturvedi, S. Chaty, A. Chen, A. H. -Y. Chen, D. Chen, H. Chen, H. Y. Chen, S. Chen, Yanbei Chen, Yitian Chen, H. P. Cheng, P. Chessa, H. T. Cheung, S. Y. Cheung, F. Chiadini, G. Chiarini, A. Chiba, A. Chincarini, M. L. Chiofalo, A. Chiummo, C. Chou, S. Choudhary, N. Christensen, S. S. Y. Chua, G. Ciani, P. Ciecielag, M. Cieślar, M. Cifaldi, B. Cirok, F. Clara, J. A. Clark, T. A. Clarke, P. Clearwater, S. Clesse, F. Cleva, E. Coccia, E. Codazzo, P. -F. Cohadon, S. Colace, E. Colangeli, M. Colleoni, C. G. Collette, J. Collins, S. Colloms, A. Colombo, C. M. Compton, G. Connolly, L. Conti, T. R. Corbitt, I. Cordero-Carrión, S. Corezzi, N. J. Cornish, I. Coronado, A. Corsi, R. Cottingham, M. W. Coughlin, A. Couineaux, P. Couvares, D. M. Coward, R. Coyne, A. Cozzumbo, J. D. E. Creighton, T. D. Creighton, P. Cremonese, S. Crook, R. Crouch, J. Csizmazia, J. R. Cudell, T. J. Cullen, A. Cumming, E. Cuoco, M. Cusinato, L. V. Da Conceição, T. Dal Canton, S. Dal Pra, G. Dálya, B. D'Angelo, S. Danilishin, S. D'Antonio, K. Danzmann, K. E. Darroch, L. P. Dartez, R. Das, A. Dasgupta, V. Dattilo, A. Daumas, N. Davari, I. Dave, A. Davenport, M. Davier, T. F. Davies, D. Davis, L. Davis, M. C. Davis, P. Davis, E. J. Daw, M. Dax, J. De Bolle, M. Deenadayalan, J. Degallaix, M. De Laurentis, F. De Lillo, S. Della Torre, W. Del Pozzo, A. Demagny, F. De Marco, G. Demasi, F. De Matteis, N. Demos, T. Dent, A. Depasse, N. DePergola, R. De Pietri, R. De Rosa, C. De Rossi, M. Desai, R. DeSalvo, A. DeSimone, R. De Simone, A. Dhani, R. Diab, M. C. Díaz, M. Di Cesare, G. Dideron, T. Dietrich, L. Di Fiore, C. Di Fronzo, M. Di Giovanni, T. Di Girolamo, D. Diksha, J. Ding, S. Di Pace, I. Di Palma, D. Di Piero, F. Di Renzo, Divyajyoti, A. Dmitriev, J. P. Docherty, Z. Doctor, N. Doerksen, E. Dohmen, A. Doke, A. Domiciano De Souza, L. D'Onofrio, F. Donovan, K. L. Dooley, T. Dooney, S. Doravari, O. Dorosh, W. J. D. Doyle, M. Drago, J. C. Driggers, L. Dunn, U. Dupletsa, P. -A. Duverne, D. D'Urso, P. Dutta Roy, H. Duval, S. E. Dwyer, C. Eassa, M. Ebersold, T. Eckhardt, G. Eddolls, A. Effler, J. Eichholz, H. Einsle, M. Eisenmann, M. Emma, K. Endo, R. Enficiaud, L. Errico, R. Espinosa, M. C. Espitia, M. Esposito, R. C. Essick, H. Estellés, T. Etzel, M. Evans, T. Evstafyeva, B. E. Ewing, J. M. Ezquiaga, F. Fabrizi, V. Fafone, S. Fairhurst, A. M. Farah, B. Farr, W. M. Farr, G. Favaro, M. Favata, M. Fays, M. Fazio, J. Feicht, M. M. Fejer, R. Felicetti, E. Fenyvesi, J. Fernandes, T. Fernandes, D. Fernando, S. Ferraiuolo, T. A. Ferreira, F. Fidecaro, P. Figura, A. Fiori, I. Fiori, M. Fishbach, R. P. Fisher, R. Fittipaldi, V. Fiumara, R. Flaminio, S. M. Fleischer, L. S. Fleming, E. Floden, H. Fong, J. A. Font, F. Fontinele-Nunes, C. Foo, B. Fornal, K. Franceschetti, F. Frappez, S. Frasca, F. Frasconi, J. P. Freed, Z. Frei, A. Freise, O. Freitas, R. Frey, W. Frischhertz, P. Fritschel, V. V. Frolov, G. G. Fronzé, M. Fuentes-Garcia, S. Fujii, T. Fujimori, P. Fulda, M. Fyffe, B. Gadre, J. R. Gair, S. Galaudage, V. Galdi, R. Gamba, A. Gamboa, S. Gamoji, D. Ganapathy, A. Ganguly, B. Garaventa, J. García-Bellido, C. García-Quirós, J. W. Gardner, K. A. Gardner, S. Garg, J. Gargiulo, X. Garrido, A. Garron, F. Garufi, P. A. Garver, C. Gasbarra, B. Gateley, F. Gautier, V. Gayathri, T. Gayer, G. Gemme, A. Gennai, V. Gennari, J. George, R. George, O. Gerberding, L. Gergely, Archisman Ghosh, Sayantan Ghosh, Shaon Ghosh, Shrobana Ghosh, Suprovo Ghosh, Tathagata Ghosh, J. A. Giaime, K. D. Giardina, D. R. Gibson, C. Gier, S. Gkaitatzis, J. Glanzer, F. Glotin, J. Godfrey, R. V. Godley, P. Godwin, A. S. Goettel, E. Goetz, J. Golomb, S. Gomez Lopez, B. Goncharov, G. González, P. Goodarzi, S. Goode, A. W. Goodwin-Jones, M. Gosselin, R. Gouaty, D. W. Gould, K. Govorkova, A. Grado, V. Graham, A. E. Granados, M. Granata, V. Granata, S. Gras, P. Grassia, J. Graves, C. Gray, R. Gray, G. Greco, A. C. Green, L. Green, S. M. Green, S. R. Green, C. Greenberg, A. M. Gretarsson, H. K. Griffin, D. Griffith, H. L. Griggs, G. Grignani, C. Grimaud, H. Grote, S. Grunewald, D. Guerra, D. Guetta, G. M. Guidi, A. R. Guimaraes, H. K. Gulati, F. Gulminelli, H. Guo, W. Guo, Y. Guo, Anuradha Gupta, I. Gupta, N. C. Gupta, S. K. Gupta, V. Gupta, N. Gupte, J. Gurs, N. Gutierrez, N. Guttman, F. Guzman, D. Haba, M. Haberland, S. Haino, E. D. Hall, E. Z. Hamilton, G. Hammond, M. Haney, J. Hanks, C. Hanna, M. D. Hannam, O. A. Hannuksela, A. G. Hanselman, H. Hansen, J. Hanson, S. Hanumasagar, R. Harada, A. R. Hardison, S. Harikumar, K. Haris, I. Harley-Trochimczyk, T. Harmark, J. Harms, G. M. Harry, I. W. Harry, J. Hart, B. Haskell, C. J. Haster, K. Haughian, H. Hayakawa, K. Hayama, M. C. Heintze, J. Heinze, J. Heinzel, H. Heitmann, F. Hellman, A. F. Helmling-Cornell, G. Hemming, O. Henderson-Sapir, M. Hendry, I. S. Heng, M. H. Hennig, C. Henshaw, M. Heurs, A. L. Hewitt, J. Heynen, J. Heyns, S. Higginbotham, S. Hild, S. Hill, Y. Himemoto, N. Hirata, C. Hirose, D. Hofman, B. E. Hogan, N. A. Holland, I. J. Hollows, D. E. Holz, L. Honet, D. J. Horton-Bailey, J. Hough, S. Hourihane, N. T. Howard, E. J. Howell, C. G. Hoy, C. A. Hrishikesh, P. Hsi, H. -F. Hsieh, H. -Y. Hsieh, C. Hsiung, S. -H. Hsu, W. -F. Hsu, Q. Hu, H. Y. Huang, Y. Huang, Y. T. Huang, A. D. Huddart, B. Hughey, V. Hui, S. Husa, R. Huxford, L. Iampieri, G. A. Iandolo, M. Ianni, G. Iannone, J. Iascau, K. Ide, R. Iden, A. Ierardi, S. Ikeda, H. Imafuku, Y. Inoue, G. Iorio, P. Iosif, M. H. Iqbal, J. Irwin, R. Ishikawa, M. Isi, T. Islam, K. S. Isleif, Y. Itoh, M. Iwaya, B. R. Iyer, C. Jacquet, P. -E. Jacquet, T. Jacquot, S. J. Jadhav, S. P. Jadhav, M. Jain, T. Jain, A. L. James, K. Jani, J. Janquart, N. N. Janthalur, S. Jaraba, P. Jaranowski, R. Jaume, W. Javed, A. Jennings, M. Jensen, W. Jia, J. Jiang, H. -B. Jin, G. R. Johns, N. A. Johnson, M. C. Johnston, R. Johnston, N. Johny, D. H. Jones, D. I. Jones, R. Jones, H. E. Jose, P. Joshi, S. K. Joshi, G. Joubert, J. Ju, L. Ju, K. Jung, J. Junker, V. Juste, H. B. Kabagoz, T. Kajita, I. Kaku, V. Kalogera, M. Kalomenopoulos, M. Kamiizumi, N. Kanda, S. Kandhasamy, G. Kang, N. C. Kannachel, J. B. Kanner, S. A. KantiMahanty, S. J. Kapadia, D. P. Kapasi, M. Karthikeyan, M. Kasprzack, H. Kato, T. Kato, E. Katsavounidis, W. Katzman, R. Kaushik, K. Kawabe, R. Kawamoto, D. Keitel, L. J. Kemperman, J. Kennington, F. A. Kerkow, R. Kesharwani, J. S. Key, R. Khadela, S. Khadka, S. S. Khadkikar, F. Y. Khalili, F. Khan, T. Khanam, M. Khursheed, N. M. Khusid, W. Kiendrebeogo, N. Kijbunchoo, C. Kim, J. C. Kim, K. Kim, M. H. Kim, S. Kim, Y. -M. Kim, C. Kimball, K. Kimes, M. Kinnear, J. S. Kissel, S. Klimenko, A. M. Knee, E. J. Knox, N. Knust, K. Kobayashi, S. M. Koehlenbeck, G. Koekoek, K. Kohri, K. Kokeyama, S. Koley, P. Kolitsidou, A. E. Koloniari, K. Komori, A. K. H. Kong, A. Kontos, L. M. Koponen, M. Korobko, X. Kou, A. Koushik, N. Kouvatsos, M. Kovalam, T. Koyama, D. B. Kozak, S. L. Kranzhoff, V. Kringel, N. V. Krishnendu, S. Kroker, A. Królak, K. Kruska, J. Kubisz, G. Kuehn, S. Kulkarni, A. Kulur Ramamohan, Achal Kumar, Anil Kumar, Praveen Kumar, Prayush Kumar, Rahul Kumar, Rakesh Kumar, J. Kume, K. Kuns, N. Kuntimaddi, S. Kuroyanagi, S. Kuwahara, K. Kwak, K. Kwan, S. Kwon, G. Lacaille, D. Laghi, A. H. Laity, E. Lalande, M. Lalleman, P. C. Lalremruati, M. Landry, B. B. Lane, R. N. Lang, J. Lange, R. Langgin, B. Lantz, I. La Rosa, J. Larsen, A. Lartaux-Vollard, P. D. Lasky, J. Lawrence, M. Laxen, C. Lazarte, A. Lazzarini, C. Lazzaro, P. Leaci, L. Leali, Y. K. Lecoeuche, H. M. Lee, H. W. Lee, J. Lee, K. Lee, R. -K. Lee, R. Lee, Sungho Lee, Sunjae Lee, Y. Lee, I. N. Legred, J. Lehmann, L. Lehner, M. Le Jean, A. Lemaître, M. Lenti, M. Leonardi, M. Lequime, N. Leroy, M. Lesovsky, N. Letendre, M. Lethuillier, Y. Levin, K. Leyde, A. K. Y. Li, K. L. Li, T. G. F. Li, X. Li, Y. Li, Z. Li, A. Lihos, E. T. Lin, F. Lin, L. C. -C. Lin, Y. -C. Lin, C. Lindsay, S. D. Linker, A. Liu, G. C. Liu, Jian Liu, F. Llamas Villarreal, J. Llobera-Querol, R. K. L. Lo, J. -P. Locquet, S. C. G. Loggins, M. R. Loizou, L. T. London, A. Longo, D. Lopez, M. Lopez Portilla, M. Lorenzini, A. Lorenzo-Medina, V. Loriette, M. Lormand, G. Losurdo, E. Lotti, T. P. Lott, J. D. Lough, H. A. Loughlin, C. O. Lousto, N. Low, N. Lu, L. Lucchesi, H. Lück, D. Lumaca, A. P. Lundgren, A. W. Lussier, R. Macas, M. MacInnis, D. M. Macleod, I. A. O. MacMillan, A. Macquet, K. Maeda, S. Maenaut, S. S. Magare, R. M. Magee, E. Maggio, R. Maggiore, M. Magnozzi, M. Mahesh, M. Maini, S. Majhi, E. Majorana, C. N. Makarem, D. Malakar, J. A. Malaquias-Reis, U. Mali, S. Maliakal, A. Malik, L. Mallick, A. -K. Malz, N. Man, M. Mancarella, V. Mandic, V. Mangano, B. Mannix, G. L. Mansell, M. Manske, M. Mantovani, M. Mapelli, C. Marinelli, F. Marion, A. S. Markosyan, A. Markowitz, E. Maros, S. Marsat, F. Martelli, I. W. Martin, R. M. Martin, B. B. Martinez, D. A. Martinez, M. Martinez, V. Martinez, A. Martini, J. C. Martins, D. V. Martynov, E. J. Marx, L. Massaro, A. Masserot, M. Masso-Reid, S. Mastrogiovanni, T. Matcovich, M. Matiushechkina, L. Maurin, N. Mavalvala, N. Maxwell, G. McCarrol, R. McCarthy, D. E. McClelland, S. McCormick, L. McCuller, S. McEachin, C. McElhenny, G. I. McGhee, J. McGinn, K. B. M. McGowan, J. McIver, A. McLeod, I. McMahon, T. McRae, R. McTeague, D. Meacher, B. N. Meagher, R. Mechum, Q. Meijer, A. Melatos, C. S. Menoni, F. Mera, R. A. Mercer, L. Mereni, K. Merfeld, E. L. Merilh, J. R. Mérou, J. D. Merritt, M. Merzougui, C. Messick, B. Mestichelli, M. Meyer-Conde, F. Meylahn, A. Mhaske, A. Miani, H. Miao, C. Michel, Y. Michimura, H. Middleton, D. P. Mihaylov, S. J. Miller, M. Millhouse, E. Milotti, V. Milotti, Y. Minenkov, E. M. Minihan, Ll. M. Mir, L. Mirasola, M. Miravet-Tenés, C. -A. Miritescu, A. Mishra, C. Mishra, T. Mishra, A. L. Mitchell, J. G. Mitchell, S. Mitra, V. P. Mitrofanov, K. Mitsuhashi, R. Mittleman, O. Miyakawa, S. Miyoki, A. Miyoko, G. Mo, L. Mobilia, S. R. P. Mohapatra, S. R. Mohite, M. Molina-Ruiz, M. Mondin, J. K. Monsalve, M. Montani, C. J. Moore, D. Moraru, A. More, S. More, C. Moreno, E. A. Moreno, G. Moreno, A. Moreso Serra, S. Morisaki, Y. Moriwaki, G. Morras, A. Moscatello, M. Mould, B. Mours, C. M. Mow-Lowry, L. Muccillo, F. Muciaccia, D. Mukherjee, Samanwaya Mukherjee, Soma Mukherjee, Subroto Mukherjee, Suvodip Mukherjee, N. Mukund, A. Mullavey, H. Mullock, J. Mundi, C. L. Mungioli, M. Murakoshi, P. G. Murray, D. Nabari, S. L. Nadji, A. Nagar, N. Nagarajan, K. Nakagaki, K. Nakamura, H. Nakano, M. Nakano, D. Nanadoumgar-Lacroze, D. Nandi, V. Napolano, P. Narayan, I. Nardecchia, T. Narikawa, H. Narola, L. Naticchioni, R. K. Nayak, L. Negri, A. Nela, C. Nelle, A. Nelson, T. J. N. Nelson, M. Nery, A. Neunzert, S. Ng, L. Nguyen Quynh, S. A. Nichols, A. B. Nielsen, Y. Nishino, A. Nishizawa, S. Nissanke, W. Niu, F. Nocera, J. Noller, M. Norman, C. North, J. Novak, R. Nowicki, J. F. Nuño Siles, L. K. Nuttall, K. Obayashi, J. Oberling, J. O'Dell, E. Oelker, M. Oertel, G. Oganesyan, T. O'Hanlon, M. Ohashi, F. Ohme, R. Oliveri, R. Omer, B. O'Neal, M. Onishi, K. Oohara, B. O'Reilly, M. Orselli, R. O'Shaughnessy, S. O'Shea, S. Oshino, C. Osthelder, I. Ota, D. J. Ottaway, A. Ouzriat, H. Overmier, B. J. Owen, R. Ozaki, A. E. Pace, R. Pagano, M. A. Page, A. Pai, L. Paiella, A. Pal, S. Pal, M. A. Palaia, M. Pálfi, P. P. Palma, C. Palomba, P. Palud, H. Pan, J. Pan, K. C. Pan, P. K. Panda, Shiksha Pandey, Swadha Pandey, P. T. H. Pang, F. Pannarale, K. A. Pannone, B. C. Pant, F. H. Panther, M. Panzeri, F. Paoletti, A. Paolone, A. Papadopoulos, E. E. Papalexakis, L. Papalini, G. Papigkiotis, A. Paquis, A. Parisi, B. -J. Park, J. Park, W. Parker, G. Pascale, D. Pascucci, A. Pasqualetti, R. Passaquieti, L. Passenger, D. Passuello, O. Patane, A. V. Patel, D. Pathak, A. Patra, B. Patricelli, B. G. Patterson, K. Paul, S. Paul, E. Payne, T. Pearce, M. Pedraza, A. Pele, F. E. Peña Arellano, X. Peng, Y. Peng, S. Penn, M. D. Penuliar, A. Perego, Z. Pereira, C. Périgois, G. Perna, A. Perreca, J. Perret, S. Perriès, J. W. Perry, D. Pesios, S. Peters, S. Petracca, C. Petrillo, H. P. Pfeiffer, H. Pham, K. A. Pham, K. S. Phukon, H. Phurailatpam, M. Piarulli, L. Piccari, O. J. Piccinni, M. Pichot, M. Piendibene, F. Piergiovanni, L. Pierini, G. Pierra, V. Pierro, M. Pietrzak, M. Pillas, F. Pilo, L. Pinard, I. M. Pinto, M. Pinto, B. J. Piotrzkowski, M. Pirello, M. D. Pitkin, A. Placidi, E. Placidi, M. L. Planas, W. Plastino, C. Plunkett, R. Poggiani, E. Polini, J. Pomper, L. Pompili, J. Poon, E. Porcelli, E. K. Porter, C. Posnansky, R. Poulton, J. Powell, G. S. Prabhu, M. Pracchia, B. K. Pradhan, T. Pradier, A. K. Prajapati, K. Prasai, R. Prasanna, P. Prasia, G. Pratten, G. Principe, G. A. Prodi, P. Prosperi, P. Prosposito, A. C. Providence, A. Puecher, J. Pullin, P. Puppo, M. Pürrer, H. Qi, J. Qin, G. Quéméner, V. Quetschke, L. H. Quiceno, P. J. Quinonez, N. Qutob, F. J. Raab, R. Rading, I. Rainho, S. Raja, C. Rajan, B. Rajbhandari, K. E. Ramirez, F. A. Ramis Vidal, M. Ramos Arevalo, A. Ramos-Buades, S. Ranjan, K. Ransom, P. Rapagnani, B. Ratto, A. Ravichandran, A. Ray, V. Raymond, M. Razzano, J. Read, T. Regimbau, S. Reid, C. Reissel, D. H. Reitze, A. I. Renzini, A. Renzini, B. Revenu, A. Revilla Peña, R. Reyes, L. Ricca, F. Ricci, M. Ricci, A. Ricciardone, J. Rice, J. W. Richardson, M. L. Richardson, A. Rijal, K. Riles, H. K. Riley, S. Rinaldi, J. Rittmeyer, C. Robertson, F. Robinet, M. Robinson, A. Rocchi, L. Rolland, J. G. Rollins, A. E. Romano, R. Romano, A. Romero, I. M. Romero-Shaw, J. H. Romie, S. Ronchini, T. J. Roocke, L. Rosa, T. J. Rosauer, C. A. Rose, D. Rosińska, M. P. Ross, M. Rossello-Sastre, S. Rowan, S. K. Roy, S. Roy, D. Rozza, P. Ruggi, N. Ruhama, E. Ruiz Morales, K. Ruiz-Rocha, S. Sachdev, T. Sadecki, P. Saffarieh, S. Safi-Harb, M. R. Sah, S. Saha, T. Sainrat, S. Sajith Menon, K. Sakai, Y. Sakai, M. Sakellariadou, S. Sakon, O. S. Salafia, F. Salces-Carcoba, L. Salconi, M. Saleem, F. Salemi, M. Sallé, S. U. Salunkhe, S. Salvador, A. Salvarese, A. Samajdar, A. Sanchez, E. J. Sanchez, L. E. Sanchez, N. Sanchis-Gual, J. R. Sanders, E. M. Sänger, F. Santoliquido, F. Sarandrea, T. R. Saravanan, N. Sarin, P. Sarkar, A. Sasli, P. Sassi, B. Sassolas, B. S. Sathyaprakash, R. Sato, S. Sato, Yukino Sato, Yu Sato, O. Sauter, R. L. Savage, T. Sawada, H. L. Sawant, S. Sayah, V. Scacco, D. Schaetzl, M. Scheel, A. Schiebelbein, M. G. Schiworski, P. Schmidt, S. Schmidt, R. Schnabel, M. Schneewind, R. M. S. Schofield, K. Schouteden, B. W. Schulte, B. F. Schutz, E. Schwartz, M. Scialpi, J. Scott, S. M. Scott, R. M. Sedas, T. C. Seetharamu, M. Seglar-Arroyo, Y. Sekiguchi, D. Sellers, N. Sembo, A. S. Sengupta, E. G. Seo, J. W. Seo, V. Sequino, M. Serra, A. Sevrin, T. Shaffer, U. S. Shah, M. A. Shaikh, L. Shao, A. K. Sharma, Preeti Sharma, Prianka Sharma, Ritwik Sharma, S. Sharma Chaudhary, P. Shawhan, N. S. Shcheblanov, E. Sheridan, Z. -H. Shi, M. Shikauchi, R. Shimomura, H. Shinkai, S. Shirke, D. H. Shoemaker, D. M. Shoemaker, R. W. Short, S. ShyamSundar, A. Sider, H. Siegel, D. Sigg, L. Silenzi, L. Silvestri, M. Simmonds, L. P. Singer, Amitesh Singh, Anika Singh, D. Singh, N. Singh, S. Singh, A. M. Sintes, V. Sipala, V. Skliris, B. J. J. Slagmolen, D. A. Slater, T. J. Slaven-Blair, J. Smetana, J. R. Smith, L. Smith, R. J. E. Smith, W. J. Smith, S. Soares de Albuquerque Filho, M. Soares-Santos, K. Somiya, I. Song, S. Soni, V. Sordini, F. Sorrentino, H. Sotani, F. Spada, V. Spagnuolo, A. P. Spencer, P. Spinicelli, A. K. Srivastava, F. Stachurski, C. J. Stark, D. A. Steer, N. Steinle, J. Steinlechner, S. Steinlechner, N. Stergioulas, P. Stevens, M. StPierre, M. D. Strong, A. Strunk, A. L. Stuver, M. Suchenek, S. Sudhagar, Y. Sudo, N. Sueltmann, L. Suleiman, K. D. Sullivan, J. Sun, L. Sun, S. Sunil, J. Suresh, B. J. Sutton, P. J. Sutton, K. Suzuki, M. Suzuki, B. L. Swinkels, A. Syx, M. J. Szczepańczyk, P. Szewczyk, M. Tacca, H. Tagoshi, K. Takada, H. Takahashi, R. Takahashi, A. Takamori, S. Takano, H. Takeda, K. Takeshita, I. Takimoto Schmiegelow, M. Takou-Ayaoh, C. Talbot, M. Tamaki, N. Tamanini, D. Tanabe, K. Tanaka, S. J. Tanaka, S. Tanioka, D. B. Tanner, W. Tanner, L. Tao, R. D. Tapia, E. N. Tapia San Martín, C. Taranto, A. Taruya, J. D. Tasson, J. G. Tau, D. Tellez, R. Tenorio, H. Themann, A. Theodoropoulos, M. P. Thirugnanasambandam, L. M. Thomas, M. Thomas, P. Thomas, J. E. Thompson, S. R. Thondapu, K. A. Thorne, E. Thrane, J. Tissino, A. Tiwari, Pawan Tiwari, Praveer Tiwari, S. Tiwari, V. Tiwari, M. R. Todd, M. Toffano, A. M. Toivonen, K. Toland, A. E. Tolley, T. Tomaru, V. Tommasini, T. Tomura, H. Tong, C. Tong-Yu, A. Torres-Forné, C. I. Torrie, I. Tosta e Melo, E. Tournefier, M. Trad Nery, K. Tran, A. Trapananti, R. Travaglini, F. Travasso, G. Traylor, M. Trevor, M. C. Tringali, A. Tripathee, G. Troian, A. Trovato, L. Trozzo, R. J. Trudeau, T. Tsang, S. Tsuchida, L. Tsukada, K. Turbang, M. Turconi, C. Turski, H. Ubach, N. Uchikata, T. Uchiyama, R. P. Udall, T. Uehara, K. Ueno, V. Undheim, L. E. Uronen, T. Ushiba, M. Vacatello, H. Vahlbruch, N. Vaidya, G. Vajente, A. Vajpeyi, J. Valencia, M. Valentini, S. A. Vallejo-Peña, S. Vallero, V. Valsan, M. van Dael, E. Van den Bossche, J. F. J. van den Brand, C. Van Den Broeck, M. van der Sluys, A. Van de Walle, J. van Dongen, K. Vandra, M. VanDyke, H. van Haevermaet, J. V. van Heijningen, P. Van Hove, J. Vanier, M. VanKeuren, J. Vanosky, N. van Remortel, M. Vardaro, A. F. Vargas, V. Varma, A. N. Vazquez, A. Vecchio, G. Vedovato, J. Veitch, P. J. Veitch, S. Venikoudis, R. C. Venterea, P. Verdier, M. Vereecken, D. Verkindt, B. Verma, Y. Verma, S. M. Vermeulen, F. Vetrano, A. Veutro, A. Viceré, S. Vidyant, A. D. Viets, A. Vijaykumar, A. Vilkha, N. Villanueva Espinosa, V. Villa-Ortega, E. T. Vincent, J. -Y. Vinet, S. Viret, S. Vitale, H. Vocca, D. Voigt, E. R. G. von Reis, J. S. A. von Wrangel, W. E. Vossius, L. Vujeva, S. P. Vyatchanin, J. Wack, L. E. Wade, M. Wade, K. J. Wagner, L. Wallace, E. J. Wang, H. Wang, J. Z. Wang, W. H. Wang, Y. F. Wang, G. Waratkar, J. Warner, M. Was, T. Washimi, N. Y. Washington, D. Watarai, B. Weaver, S. A. Webster, N. L. Weickhardt, M. Weinert, A. J. Weinstein, R. Weiss, L. Wen, K. Wette, J. T. Whelan, B. F. Whiting, C. Whittle, E. G. Wickens, D. Wilken, A. T. Wilkin, B. M. Williams, D. Williams, M. J. Williams, N. S. Williams, J. L. Willis, B. Willke, M. Wils, L. Wilson, C. W. Winborn, J. Winterflood, C. C. Wipf, G. Woan, J. Woehler, N. E. Wolfe, H. T. Wong, I. C. F. Wong, K. Wong, T. Wouters, J. L. Wright, M. Wright, B. Wu, C. Wu, D. S. Wu, H. Wu, K. Wu, Q. Wu, Y. Wu, Z. Wu, E. Wuchner, D. M. Wysocki, V. A. Xu, Y. Xu, N. Yadav, H. Yamamoto, K. Yamamoto, T. S. Yamamoto, T. Yamamoto, R. Yamazaki, T. Yan, K. Z. Yang, Y. Yang, Z. Yarbrough, J. Yebana, S. -W. Yeh, A. B. Yelikar, X. Yin, J. Yokoyama, T. Yokozawa, S. Yuan, H. Yuzurihara, M. Zanolin, M. Zeeshan, T. Zelenova, J. -P. Zendri, M. Zeoli, M. Zerrad, M. Zevin, L. Zhang, N. Zhang, R. Zhang, T. Zhang, C. Zhao, Yue Zhao, Yuhang Zhao, Z. -C. Zhao, Y. Zheng, H. Zhong, H. Zhou, H. O. Zhu, Z. -H. Zhu, L. Zimmermann, M. E. Zucker, J. Zweizig
Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine the universe is a giant, cosmic concert hall, and for the last few years, the LIGO-Virgo-KAGRA team has been the ultimate sound engineers, listening for the music of the cosmos. Usually, they are tuned in to hear the sharp, quick "chirps" of black holes or neutron stars crashing into each other—like two marbles colliding in a split second. But what if the music isn't a quick crash? What if it's a long, slow, groaning note that lasts for minutes or even hours?
That's exactly what this paper is about. The team went on a massive "all-sky" hunt during the first part of their fourth big listening session (called O4a, which ran from May 24, 2023, to January 16, 2024) to find these long-duration gravitational waves. These are signals that last longer than one second, potentially stretching up to 1,000 seconds.
The Great Cosmic Silence (For Now)
Here is the big news: They didn't find any new long-duration signals.
Think of it like tuning a radio to a station that might be broadcasting a secret message. The team turned the dial to every possible frequency between 16 Hz and 2048 Hz, listening for weird, long-lasting noises that could come from things like:
- Magnetars: Super-dense stars with magnetic fields so strong they could rip a credit card from your hand from a thousand miles away. If these stars wobble or deform, they might hum a long, low note.
- Eccentric Binaries: Instead of two stars spiraling in a perfect circle like a figure skater, imagine them swinging in a wild, oval-shaped dance (an eccentric orbit). This could create a long, drawn-out gravitational wave signal.
- Falling Debris: Imagine a newborn black hole or neutron star eating up a cloud of leftover gas. This "fallback accretion" could create a long, chaotic rumble.
The team used two different super-smart computer pipelines (called cWB and PySTAMPAS) to scan the data. It's like having two different detectives looking at the same crime scene with different magnifying glasses. One detective uses a machine learning tool called XGBoost to help sort through the noise, while the other uses a method called PySTAMPAS that builds a detailed map of the sound energy over time.
The "Glitch" Problem
The universe is noisy. Just like a radio has static, these detectors pick up "glitches"—little bursts of noise from earthquakes, trucks driving by, or even the detectors themselves getting a little jittery.
The team found a few "candidates" that looked interesting at first. One signal had a loudness (Signal-to-Noise Ratio) of 11 and lasted a moment, but it happened during a time when the detectors were having a lot of glitches. The team calculated that there was a 38% chance this was just random noise. Since that's a high probability for a "false alarm," they ruled it out. Another candidate from the other pipeline had a 52% chance of being noise.
The verdict: All the signals they found were consistent with background noise. They explicitly ruled out the idea that they had detected a new, confirmed long-duration gravitational wave event in this specific dataset.
How Good Was the Search?
Even though they didn't find a signal, they didn't come up empty-handed. They proved their search was 30% better than their previous hunt in the third observing run (O3).
Think of it like upgrading from a pair of binoculars to a high-powered telescope. They didn't find a new planet, but they proved their telescope is sharp enough to see much further.
- The Reach: They could now detect signals with a specific "strength" (called root-sum-square amplitude, or hrss) that was 30% weaker than what they could catch before.
- The Frequency: They scanned a wide range of frequencies, from 16 Hz to 2048 Hz.
- The Duration: They looked for signals lasting anywhere from 1 second to 1,000 seconds.
What Does This Mean for the Future?
The paper suggests that while we haven't heard the "long song" yet, the instruments are getting better at listening for it. The team used simulations to show that if these long signals were happening, their new setup would have a much better chance of catching them than before.
They also set some strict limits on how often these "eccentric" binary collisions (the wild, oval-dancing stars) might be happening. They calculated that if these events are happening, they occur less than 18,000 times per year in a volume of space the size of a billion cubic gigaparsecs (a huge number, but a small rate for the whole universe).
The Bottom Line
This paper is a report on a very thorough, very sensitive search that came up empty. But in science, knowing what isn't there is just as important as knowing what is. The team has shown that their "ears" are sharper and their "filters" are smarter. They have ruled out the possibility that these long-duration signals are happening as frequently as some theories might have hoped, at least within the range they could hear.
As the detectors get even more sensitive and the listening runs get longer, the team suggests that the day might come when we finally hear that long, cosmic groan from a wobbling magnetar or a wild, eccentric dance of two stars. Until then, the universe remains silent on this specific note, but the search continues with better tools than ever before.
Technical Summary: All-sky search for long-duration gravitational-wave transients in the first part of the fourth LIGO-Virgo-KAGRA Observing run
Problem and Motivation
While the direct detection of gravitational waves (GWs) has been dominated by compact binary coalescences (CBCs), a wide variety of astrophysical scenarios predict GW signals that are long-duration (≳1 s) and unmodeled. These include non-axisymmetric deformations in newborn neutron stars (NSs) or magnetars, fallback accretion onto NSs or black holes (BHs), accretion disk instabilities, and high-eccentricity compact binary coalescences (ECBCs). Unlike CBCs, which are typically well-modeled and searched for using matched filtering, these long-duration transients require unmodeled, "burst" search strategies that make minimal assumptions regarding waveform morphology and duration. This paper presents an all-sky search for such signals using data from the first part of the fourth LIGO-Virgo-KAGRA observing run (O4a), updating and extending previous results from the O2 and O3 runs.
Methodology
The analysis utilized 125 days of coincident data from the LIGO Hanford (LHO) and LIGO Livingston (LLO) detectors collected between May 24, 2023, and January 16, 2024. KAGRA data were excluded due to significantly lower sensitivity during O4a. The search targeted signals with durations of approximately 1–1000 seconds and frequencies between 16–2048 Hz.
Two independent, unmodeled search pipelines were employed to ensure robustness against different signal morphologies:
- Coherent Wave Burst (cWB): This pipeline uses a multi-resolution wavelet transform (Wilson-Daubechies-Meyer) to identify excess power in time-frequency pixels. A key methodological advancement in this analysis is the application of an XGBoost supervised machine learning classifier in the post-processing stage. This classifier re-weights the network coherent signal-to-noise ratio (SNR), replacing the rigid duration cuts used in previous runs. This allows for a broader parameter space search and improved discrimination against noise transients.
- PySTAMPAS: An enhanced version of the Stochastic Transient Analysis Multi-detector Pipeline, designed for reduced computational cost. It constructs multi-resolution spectrograms using Short-Time Fourier Transforms (STFT) and employs a seed-based clustering algorithm to identify candidate triggers. It utilizes a robust median power spectral density (PSD) estimation to handle non-Gaussian noise.
Both pipelines utilized time-shifted data to estimate background noise distributions, calculating the inverse false-alarm rate (iFAR). A detection threshold of iFAR > 50 years was set. To quantify sensitivity in the absence of detections, the authors injected simulated waveforms representing various astrophysical scenarios (e.g., magnetars, ECBCs, accretion disk instabilities) into the data and measured detection efficiency.
Key Contributions
- First Application of XGBoost to Long-Duration Searches: This work marks the first use of the XGBoost classifier within the cWB pipeline for long-duration GW searches, replacing previous heuristic duration cuts and enhancing sensitivity.
- First PySTAMPAS All-Sky Search: This presents the first all-sky search for long-duration GWs using the PySTAMPAS pipeline.
- Improved Efficiency Estimation: The authors refined the method for calculating rate upper limits. They replaced the sigmoid fit used in O3 with a quadratic interpolation for detection efficiency curves and constrained the maximum integration distance (rmax) to the highest sampled distance. This addresses previous systematic overestimations of detection volumes and underestimations of rate limits.
- Comprehensive Waveform Coverage: The analysis tested sensitivity against a diverse set of reference waveforms, including new models for binary NS inspirals, millisecond magnetars, and fallback accretion, alongside previously tested magnetar and ECBC models.
Results
- No Significant Detections: Neither pipeline identified any GW candidates with statistical significance exceeding the 50-year iFAR threshold. The most significant triggers had false alarm probabilities (FAP) of 0.38 (cWB) and 0.52 (PySTAMPAS), consistent with noise fluctuations.
- Sensitivity Improvements: The root-sum-square strain amplitude (hrss) at 50% detection efficiency improved by approximately 30% on average across the detector bandwidth compared to O3 results.
- Sensitivity to ECBCs improved by a factor of up to 2, largely due to the XGBoost classifier's ability to distinguish these signals from noise.
- Sensitivity to monochromatic sine-Gaussian bursts improved by a factor of ~10, attributed to more robust PSD estimation in PySTAMPAS.
- Sensitivity to magnetar waveforms did not show significant improvement over O3, as these signals are best recovered by seedless clustering strategies not yet fully implemented in PySTAMPAS for this run.
- Rate Upper Limits: The study derived 90% confidence level upper limits on the rate of ECBC events. These limits range from 4.2×102 to 1.8×104 Gpc−3yr−1, depending on component mass and eccentricity. These constraints are consistent with current astrophysical expectations that only a small fraction of CBC systems possess high eccentricity.
Significance
The paper claims that this analysis demonstrates "substantial progress" in the ability to search for long-duration GW signals. The improvements are attributed to both the enhanced sensitivity of the LIGO detectors in O4a and specific algorithmic enhancements in the search pipelines (XGBoost and PySTAMPAS). The authors state that as detector sensitivities continue to advance and observing runs lengthen, unmodeled long-duration searches will increasingly be capable of exploring compelling astrophysical scenarios involving neutron stars and black holes. Furthermore, the pipeline improvements described are noted to have potential benefits for triggered searches for post-merger signals, addressing open questions regarding the nature of merger remnants.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.
Get the best general relativity papers every week.
Trusted by researchers at Stanford, Cambridge, and the French Academy of Sciences.
Check your inbox to confirm your subscription.
Something went wrong. Try again?
No spam, unsubscribe anytime.