Characterizing and Mitigating Intraday Variability: Reconstructing Source Structure in Accreting Black Holes with mm-VLBI

DOI: 
10.3847/2041-8213/ac6584
Publication date: 
08/05/2022
Main author: 
Broderick, Avery E.
IAA authors: 
Alberdi, Antxon;Cho, Ilje;Fuentes, Antonio;Gómez, José L.;Lico, Rocco;Traianou, Efthalia;Zhao, Guang-Yao
Authors: 
Broderick, Avery E.;Gold, Roman;Georgiev, Boris;Pesce, Dominic W.;Tiede, Paul;Ni, Chunchong;Moriyama, Kotaro;Akiyama, Kazunori;Alberdi, Antxon;Alef, Walter;Algaba, Juan Carlos;Anantua, Richard;Asada, Keiichi;Azulay, Rebecca;Bach, Uwe;Baczko, Anne-Kathrin;Ball, David;Baloković, Mislav;Barrett, John;Bauböck, Michi;Benson, Bradford A.;Bintley, Dan;Blackburn, Lindy;Blundell, Raymond;Bouman, Katherine L.;Bower, Geoffrey C.;Boyce, Hope;Bremer, Michael;Brinkerink, Christiaan D.;Brissenden, Roger;Britzen, Silke;Broguiere, Dominique;Bronzwaer, Thomas;Bustamante, Sandra;Byun, Do-Young;Carlstrom, John E.;Ceccobello, Chiara;Chael, Andrew;Chan, Chi-kwan;Chatterjee, Koushik;Chatterjee, Shami;Chen, Ming-Tang;Chen, Yongjun;Cheng, Xiaopeng;Cho, Ilje;Christian, Pierre;Conroy, Nicholas S.;Conway, John E.;Cordes, James M.;Crawford, Thomas M.;Crew, Geoffrey B.;Cruz-Osorio, Alejandro;Cui, Yuzhu;Davelaar, Jordy;De Laurentis, Mariafelicia;Deane, Roger;Dempsey, Jessica;Desvignes, Gregory;Dexter, Jason;Dhruv, Vedant;Doeleman, Sheperd S.;Dougal, Sean;Dzib, Sergio A.;Eatough, Ralph P.;Emami, Razieh;Falcke, Heino;Farah, Joseph;Fish, Vincent L.;Fomalont, Ed;Ford, H. Alyson;Fraga-Encinas, Raquel;Freeman, William T.;Friberg, Per;Fromm, Christian M.;Fuentes, Antonio;Galison, Peter;Gammie, Charles F.;García, Roberto;Gentaz, Olivier;Goddi, Ciriaco;Gómez-Ruiz, Arturo I.;Gómez, José L.;Gu, Minfeng;Gurwell, Mark;Hada, Kazuhiro;Haggard, Daryl;Haworth, Kari;Hecht, Michael H.;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;Jiménez-Rosales, Alejandra;Johnson, Michael D.;Jorstad, Svetlana;Joshi, Abhishek V.;Jung, Taehyun;Karami, Mansour;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, Michael;Krichbaum, Thomas P.;Kuo, Cheng-Yu;La Bella, Noemi;Lauer, Tod R.;Lee, Daeyoung;Lee, Sang-Sung;Leung, Po Kin;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.;Lu, Ru-Sen;Mao, Jirong;Marchili, Nicola;Markoff, Sera;Marrone, Daniel P.;Marscher, Alan P.;Martí-Vidal, Iván;Matsushita, Satoki;Matthews, Lynn D.;Menten, Karl M.;Michalik, Daniel;Mizuno, Izumi;Mizuno, Yosuke;Moran, James M.;Moscibrodzka, Monika;Müller, Cornelia;Mus, Alejandro;Musoke, Gibwa;Myserlis, Ioannis;Nadolski, Andrew;Nagai, Hiroshi;Nagar, Neil M.;Nakamura, Masanori;Narayan, Ramesh;Narayanan, Gopal;Natarajan, Iniyan;Nathanail, Antonios;Navarro Fuentes, Santiago;Neilsen, Joey;Neri, Roberto;Noutsos, Aristeidis;Nowak, Michael A.;Oh, Junghwan;Okino, Hiroki;Olivares, Héctor;Ortiz-León, Gisela N.;Oyama, Tomoaki;Palumbo, Daniel C. M.;Paraschos, Georgios Filippos;Park, Jongho;Parsons, Harriet;Patel, Nimesh;Pen, Ue-Li;Piétu, Vincent;Plambeck, Richard;PopStefanija, Aleksandar;Porth, Oliver;Pötzl, Felix M.;Prather, Ben;Preciado-López, Jorge A.;Pu, Hung-Yi;Ramakrishnan, Venkatessh;Rao, Ramprasad;Rawlings, Mark G.;Raymond, Alexander W.;Rezzolla, Luciano;Ricarte, Angelo;Ripperda, Bart;Roelofs, Freek;Rogers, Alan;Ros, Eduardo;Romero-Cañizales, Cristina;Roshanineshat, Arash;Rottmann, Helge;Roy, Alan L.;Ruiz, Ignacio;Ruszczyk, Chet;Rygl, Kazi L. J.;Sánchez, Salvador;Sánchez-Argüelles, David;Sánchez-Portal, Miguel;Sasada, Mahito;Satapathy, Kaushik;Savolainen, Tuomas;Schloerb, F. Peter;Schonfeld, Jonathan;Schuster, Karl-Friedrich;Shao, Lijing;Shen, Zhiqiang;Small, Des;Sohn, Bong Won;SooHoo, Jason;Souccar, Kamal;Sun, He;Tazaki, Fumie;Tetarenko, Alexandra J.;Tilanus, Remo P. J.;Titus, Michael;Torne, Pablo;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;Wex, Norbert;Wharton, Robert;Wielgus, Maciek;Wiik, Kaj;Witzel, Gunther;Wondrak, Michael F.;Wong, George N.;Wu, Qingwen;Yamaguchi, Paul;Yoon, Doosoo;Young, André;Young, Ken;Younsi, Ziri;Yuan, Feng;Yuan, Ye-Fei;Zensus, J. Anton;Zhao, Guang-Yao;Zhang, Shuo;Zhao, Shan-Shan
Journal: 
The Astrophysical Journal
Publication type: 
Article
Volume: 
930
Pages: 
L21
Abstract: 
The extraordinary physical resolution afforded by the Event Horizon Telescope has opened a window onto the astrophysical phenomena unfolding on horizon scales in two known black holes, M87* and Sgr A*. However, with this leap in resolution has come a new set of practical complications. Sgr A* exhibits intraday variability that violates the assumptions underlying Earth aperture synthesis, limiting traditional image reconstruction methods to short timescales and data sets with very sparse (u, v) coverage. We present a new set of tools to detect and mitigate this variability. We develop a data-driven, model-agnostic procedure to detect and characterize the spatial structure of intraday variability. This method is calibrated against a large set of mock data sets, producing an empirical estimator of the spatial power spectrum of the brightness fluctuations. We present a novel Bayesian noise modeling algorithm that simultaneously reconstructs an average image and statistical measure of the fluctuations about it using a parameterized form for the excess variance in the complex visibilities not otherwise explained by the statistical errors. These methods are validated using a variety of simulated data, including general relativistic magnetohydrodynamic simulations appropriate for Sgr A* and M87*. We find that the reconstructed source structure and variability are robust to changes in the underlying image model. We apply these methods to the 2017 EHT observations of M87*, finding evidence for variability across the EHT observing campaign. The variability mitigation strategies presented are widely applicable to very long baseline interferometry observations of variable sources generally, for which they provide a data-informed averaging procedure and natural characterization of inter-epoch image consistency.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2022ApJ...930L..21B/abstract
ADS Bibcode: 
2022ApJ...930L..21B
Keywords: 
Galactic center;Black holes;Radio astronomy;Very long baseline interferometry;Time domain astronomy;Astronomy data analysis;Computational astronomy;565;162;1338;1769;2109;1858;293