A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Full-polarization millimeter wavelength variability of Sagittarius A* during the 2018 EHT campaign
Tekijät: Albentosa-Ruiz, Ezequiel; Washington, Jasmin E.; Marchili, Nicola; Marti-Vidal, Ivan; Goddi, Ciriaco; Wielgus, Maciek; Mus, Alejandro; Ricarte, Angelo; Marrone, Daniel P.; Salas, Leon D. S.; Iwata, Yuhei; Carlos, Douglas F.; Tetarenko, Alexandra J.; Moriyama, Kotaro; Dhruv, Vedant; Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Baczko, Anne-Kathrin; Ball, David; Balokovic, Mislav; Bandyopadhyay, Bidisha; Barrett, John; Baubock, Michi; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Carlstrom, John E.; Chael, Andrew; Chan, Chi-kwan; Chang, Dominic O.; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Christian, Pierre; Cho, Ilje; Conroy, Nicholas S.; Conway, John E.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Curd, Brandon; Dahale, Rohan; Davelaar, Jordy; De laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Dihingia, Indu K.; Doeleman, Sheperd S.; Dzib, Sergio A.; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Edward; Ford, H. Alyson; Foschi, Marianna; Fuentes, Antonio; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Galison, Peter; Gammie, Charles F.; Garcia, Roberto; Gentaz, Olivier; Geertsema, Gertie; Georgiev, Boris; Gold, Roman; Gomez, Jose L.; Gomez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Impellizzeri, C. M. Violette; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Johnson, Michael D.; Jones, Adam C.; Jorstad, Svetlana; Joshi, Abhishek V.; Jung, Taehyun; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kocherlakota, Prashant; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Joana A.; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; La Bella, Noemi; Lee, Sang-Sung; Levis, Aviad; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Lisakov, Mikhail; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin J.; Lowitz, Amy E.; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marko, Sera; Marscher, Alan P.; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Izumi; Mizuno, Yosuke; Montgomery, Joshua; Moran, James M.; Moscibrodzka, Monika; Mulaudzi, Wanga; Mueller, Hendrik; Mueller, Cornelia; Musoke, Gibwa; Myserlis, Ioannis; Nagai, Hiroshi; Nagar, Neil M.; Nair, Dhanya G.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Fuentes, Santiago Navarro; Neilsen, Joey; Ni, Chunchong; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Sanchez, Hector Raul Olivares; Oyama, Tomoaki; Ozel, Feryal; Palumbo, Daniel C. M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Pietu, Vincent; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Principe, Giacomo; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Rezzolla, Luciano; Ripperda, Bart; Roder, Jan; Roelofs, Freek; Romero-Canizales, Cristina; Ros, Eduardo; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L. J.; Sanchez, Salvador; Sanchez-Arguelles, David; Sanchez-Portal, Miguel; Sasada, Mahito; Satapathy, Kaushik; Saurabh; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Silpa, Sasikumar; Small, Des; Sohn, Bong Won; SooHoo, Jason; Souccar, Kamal; Stanway, Joshua S.; Sun, He; Tazaki, Fumie; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Toscano, Teresa; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; Turk, Matthew; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Vos, Jesse; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Weintroub, Jonathan; Wharton, Robert; Wiik, Kaj; Witzel, Gunther; Wondrak, Michael F.; Wong, George N.; Wu, Qingwen; Yadlapalli, Nitika; Yamaguchi, Paul; Yfantis, Aristomenis; Yoon, Doosoo; Young, Andre; Younsi, Ziri; Yu, Wei; Yuan, Feng; Yuan, Ye-Fei; Zeng, Ai-Ling; Zensus, J. Anton; Zhang, Shuo; Zhao, Guang-Yao; Zhao, Shan-Shan
Kustantaja: EDP Sciences
Julkaisuvuosi: 2026
Lehti: Astronomy and Astrophysics
Artikkelin numero: A179
Vuosikerta: 708
ISSN: 0004-6361
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202556759
Julkaisun avoimuus kirjaamishetkellä: Avoimesti saatavilla
Julkaisukanavan avoimuus : Kokonaan avoin julkaisukanava
Verkko-osoite: https://doi.org/10.1051/0004-6361/202556759
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/523298345
Rinnakkaistallenteen lisenssi: CC BY
Rinnakkaistallennetun julkaisun versio: Kustantajan versio
Context. Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, provides a unique laboratory to study accretion dynamics and plasma processes near the event horizon.
Aims. We investigated the variability and polarization properties of Sgr A* using ALMA observations during the 2018 Event Horizon Telescope campaign.
Methods. We analyzed high-cadence full-polarization light curves from ALMA at millimeter wavelengths, performed time-series analysis, and investigated the temporal behavior during an X-ray flare observed by Chandra on 2018 April 24. The variability characteristics are compared with expectations from standard accretion flow models.
Results. We find low variability in total intensity (sigma/mu < 10%), but significantly higher variability in linear and circular polarization ( similar to 30% and similar to 50%, respectively). A time-series analysis reveals red-noise variability, with power spectral densities between 2 and 3 across all Stokes parameters. Polarized intensity shows stable intra-day timescales, while total intensity exhibits more variable timescales, suggesting distinct emission regions, with polarization likely arising from a coherent structure. On April 24, a statistically significant inter-band delay in polarized intensity coincides with a near-simultaneous X-ray and millimeter peak that deviates from the typical delayed flare scenario. This event also features enhanced millimeter variability and coherent polarization loop evolution. The observed simultaneity challenges standard models of transient synchrotron emission with cooling delays, favoring instead a scenario of continuous energy injection in an optically thin region.
Conclusions. Our results offer new constraints on the physical mechanisms driving variability in Sgr A*, and provide key observational input for refining theoretical models of accretion and plasma behavior in the vicinity of supermassive black holes.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
Julkaisussa olevat rahoitustiedot:
The Event Horizon Telescope Collaboration thanks the following organizations and programs: the Academia Sinica; the Academy of Finland (projects 274477, 284495, 312496, 315721); the Agencia Nacional de Investigacion y Desarrollo (ANID), Chile via NCN19_058 (TITANs), Fondecyt 1221421, BASAL FB210003; the Alexander von Humboldt Stiftung; an Alfred P. Sloan Research Fellowship; Allegro, the European ALMA Regional Centre node in the Netherlands, NOVA, and the astronomy institutes of the Universities of Amsterdam, Leiden, and Radboud; the ALMA North America Development Fund; the Black Hole Initiative (John Templeton Foundation grants 60477, 61497, 62286; Gordon and Betty Moore Foundation grant GBMF-8273); the Brinson Foundation; "la Caixa" Foundation (ID 100010434, LCF/BQ/DI22/11940027, LCF/BQ/DI22/11940030); the Canada Research Chairs program; Chandra grants DD7-18089X, TM6-17006X; the China Scholarship Council; the China Postdoctoral Science Foundation (2020M671266, 2022M712084); Conicyt Fondecyt Postdoctorado (3220195); Consejo Nacional de Humanidades, Ciencia y Tecnologia (CONAHCYT, Mexico, projects U0004-246083, U0004-259839, F0003-272050, M0037-279006, F0003-281692, 104497, 275201, 263356, CBF2023-2024-1102, 257435); Colfuturo Scholarship; the Junta de Andalucia (P18-FR-1769), the Consejo Superior de Investigaciones Cientificas (2019AEP112); the Delaney Family John A. Wheeler Chair at Perimeter Institute; DGAPA-UNAM (IN112820, IN108324); the Dutch Research Council (NWO) VICI award (639.043.513), grant OCENW.KLEIN.113, Dutch Black Hole Consortium (NWA 1292.19.202); Dutch Supercomputers Cartesius and Snellius (NWO 2021.013); the EACOA Fellowship (ASIAA, NAOJ, CAS, KASI); the ERC Synergy Grants "BlackHoleCam" (610058), "BlackHolistic" (10107164); EU Horizon 2020 grants RadioNet (730562), M2FINDERS (101018682), FunFiCO (777740); ERC Advanced Grant "JETSET" (884631); EU Horizon Europe SE programme New-FunFiCO (10108625); Horizon ERC 2021 programme (101040021); FAPESP (2021/01183-8); Fonds de Recherche du Quebec -Nature et Technologies (FRQNT); Fondo CAS-ANID CAS220010; Gordon and Betty Moore Foundation (GBMF-3561, GBMF-5278, GBMF-10423); the Institute for Advanced Study; the ICSC -Centro Nazionale di Ricerca in HPC, Big Data and Quantum Computing (NextGenerationEU); INFN Napoli TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at Bonn and Cologne; EU NextGenerationEU RRF M4C2 1.1 project 2022YAP-MJH; DFG research grant "Jet physics on horizon scales and beyond" (443220636); Joint Columbia/Flatiron Postdoctoral Fellowship (Simons Foundation); the Japan MEXT (JPMXP1020200109); JSPS Fellowship (JP17J08829); Joint Institute for Computational Fundamental Science, Japan; CAS Frontier Sciences Program (QYZDJ-SSW-SLH057, QYZDJSSW-SYS008, ZDBS-LY-SLH011); Leverhulme Trust Early Career Fellowship; the Max-Planck-Gesellschaft (MPG); the Max Planck Partner Group of MPG and CAS; MEXT/JSPS KAKENHI (18KK0090, JP21H01137, JP18H03721, JP18K13594, 18K03709, JP19K14761, 18H01245, 25120007, 19H01943, 21H01137, 21H04488, 22H00157, 23K03453); the Generalitat Valenciana GenT Project CIDEGENT/2018/021 and grant ASFAE/2022/018; MICINN Projects PID2019-108995GB-C22, PID2022-140888NB-C22; the Astrophysics and High Energy Physics programme by MCIN, with funding from NextGenerationEU (PRTR-C17I1). MIT International Science and Technology Initiatives (MISTI); the Ministry of Science and Technology (MOST) of Taiwan (various grants 103-110 listed); NSTC of Taiwan (111-2124-M-001-005, 112-2124-M-001-014, 112-2112-M-003-010-MY3); Taiwan MoE Yushan Young Scholar Program; National Center for Theoretical Sciences of Taiwan; NASA grants 80NSSC23K1508, 80NSSC20K0527, 80NSSC20K0645; NASA Hubble Fellowship Program (Einstein Fellowship; grants HST-HF2-51431.001-A, HST-HF2-51482.001-A, HST-HF2-51539.001-A, HST-HF2-51552.001A); NINS of Japan; National Key R&D Program of China (2016YFA0400704, 2017YFA0402703, 2016YFA0400702); NSTC (111-2112-M-001-041, 111-2124-M-001-005, 112-2124-M-001-014); the US NSF (AST-0905844, AST-0922984, AST-1126433, OIA-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1440254, AST-1555365, AST-1614868, AST-1615796, AST-1715061, AST-1716327, AST-1726637, OISE-1743747, AST-1743747, AST-1816420, AST-1935980, AST-1952099, AST-2034306, AST-2205908, AST-2307887); NSF Astronomy and Astrophysics Postdoctoral Fellowship (AST-1903847); NSERC (Canada); NRF Korea (grants NRF-2015H1D3A1066561, RS-2024-00407499, 2019R1F1A1059721, 2021R1A6A3A01086420, 2022R1C1C1005255, 2022R1F1A1075115); NOVA Virtual Institute of Accretion fellowships; NOIRLab (AURA/NSF); Onsala Space Observatory (VR grant 2017-00648); Perimeter Institute (Government of Canada and Province of Ontario); Portuguese FCT (CEEC 5th edition, UIDB/04106/2020, UIDP/04106/2020, PTDC/FIS-AST/3041/2020, CERN/FIS-PAR/0024/2021, 2022.04560.PTDC); Princeton Gravity Initiative; Ministerio de Ciencia e Innovacion, Spain (PGC2018-098915-B-C21, AYA2016-80889-P, PID2019-108995GB-C21, PID2020-117404GB-C21, RYC2023-042988-I); University of Pretoria and SuperMicro SEEDING GRANT 2020; Shanghai Municipality grant 22JC1410600; Shanghai CAS Pilot Program JCYJ-SHFY-2021-013; Spanish MCIN/AEI grant CEX2021-001131-S; the Spinoza Prize SPI 78-409; South African Research Chairs Initiative through SARAO (NRF grant 77948); Swedish Research Council (VR); the Taplin Fellowship; the Toray Science Foundation; UK STFC (ST/X508329/1); US DOE via LANL (contract 89233218CNA000001); YCAA Prize Postdoctoral Fellowship; NRF Korea/MSIT grant RS-2024-00449206; CAPES Brazil PROEX 88887.845378/2023-00; Millenium Nucleus NCN23_002 (TITANs); Comite Mixto ESO-Chile. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended sta ff of the ALMA, from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. This work has been supported by the grant PRE2020-092200 funded by MCIN/AEI/10.13039/501100011033 and by ESF invest in your future. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. We recognize that Maunakea, location of the SMA, is a culturally important site for the indigenous Hawaiian people; we are privileged to study the cosmos from its summit. This paper makes use of the following ALMA data: 2017.1.00797.V ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. We thank Frederic Vincent for his help.
