Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes
: Roelofs F, Johnson MD, Chael A, Janssen M, Wielgus M, Broderick AE, Akiyama K, Alberdi A, Alef W, Algaba JC, Anantua R, Asada K, Azulay R, Bach U, Baczko A, Ball D, Baloković M, Barrett J, Bauböck M, Benson BA, Bintley D, Blackburn L, Blundell R, Bouman KL, Bower GC, Boyce H, Bremer M, Brinkerink CD, Brissenden R, Britzen S, Broguiere D, Bronzwaer T, Bustamante S, Byun D, Carlstrom JE, Ceccobello C, Chan C, Chang DO, Chatterjee K, Chatterjee S, Chen M, Chen Y, Cheng X, Cho I, Christian P, Conroy NS, Conway JE, Cordes JM, Crawford TM, Crew GB, Cruz-Osorio A, Cui Y, Dahale R, Davelaar J, Laurentis MD, Deane R, Dempsey J, Desvignes G, Dexter J, Dhruv V, Doeleman SS, Dougal S, Dzib SA, Eatough RP, Emami R, Falcke H, Farah J, Fish VL, Fomalont E, Ford HA, Foschi M, Fraga-Encinas R, Freeman WT, Friberg P, Fromm CM, Fuentes A, Galison P, Gammie CF, García R, Gentaz O, Georgiev B, Goddi C, Gold R, Gómez-Ruiz AI, Gómez JL, Gu M, Gurwell M, Hada K, Haggard D, Haworth K, Hecht MH, Hesper R, Heumann D, Ho LC, Ho P, Honma M, Huang CL, Huang L, Hughes DH, Ikeda S, Impellizzeri CMV, Inoue M, Issaoun S, James DJ, Jannuzi BT, Jeter B, Jiang W, Jiménez-Rosales A, Jorstad S, Joshi AV, Jung T, Karami M, Karuppusamy R, Kawashima T, Keating GK, Kettenis M, Kim D, Kim J, Kim J, Kim J, Kino M, Koay JY, Kocherlakota P, Kofuji Y, Koch PM, Koyama S, Kramer C, Kramer JA, Kramer M, Krichbaum TP, Kuo C, Bella NL, Lauer TR, Lee D, Lee S, Leung PK, Levis A, Li Z, Lico R, Lindahl G, Lindqvist M, Lisakov M, Liu J, Liu K, Liuzzo E, Lo W, Lobanov AP, Loinard L, Lonsdale CJ, Lowitz AE, Lu R, MacDonald NR, Mao J, Marchili N, Markoff S, Marrone DP, Marscher AP, Martí-Vidal I, Matsushita S, Matthews LD, Medeiros L, Menten KM, Michalik D, Mizuno I, Mizuno Y, Moran JM, Moriyama K, Moscibrodzka M, Mulaudzi W, Müller C, Müller H, Mus A, Musoke G, Myserlis I, Nadolski A, Nagai H, Nagar NM, Nakamura M, Narayan R, Narayanan G, Natarajan I, Nathanail A, Fuentes SN, Neilsen J, Neri R, Ni C, Noutsos A, Nowak MA, Oh J, Okino H, Olivares H, Ortiz-León GN, Oyama T, Özel F, Palumbo DCM, Paraschos GF, Park J, Parsons H, Patel N, Pen U, Pesce DW, Piétu V, Plambeck R, PopStefanija A, Porth O, Pötzl FM, Prather B, Preciado-López JA, Psaltis D, Pu H, Ramakrishnan V, Rao R, Rawlings MG, Raymond AW, Rezzolla L, Ricarte A, Ripperda B, Rogers A, Romero-Cañizales C, Ros E, Roshanineshat A, Rottmann H, Roy AL, Ruiz I, Ruszczyk C, Rygl KLJ, Sánchez S, Sánchez-Argüelles D, Sánchez-Portal M, Sasada M, Satapathy K, Savolainen T, Schloerb FP, Schonfeld J, Schuster K, Shao L, Shen Z, Small D, Sohn BW, SooHoo J, Salas LDS, Souccar K, Sun H, Tazaki F, Tetarenko AJ, Tiede P, Tilanus RPJ, Titus M, Torne P, Toscano T, Traianou E, Trent T, Trippe S, Turk M, Bemmel I, Langevelde HJ, Rossum DR, Vos J, Wagner J, Ward-Thompson D, Wardle J, Washington JE, Weintroub J, Wharton R, Wiik K, Witzel G, Wondrak MF, Wong GN, Wu Q, Yadlapalli N, Yamaguchi P, Yfantis A, Yoon D, Young A, Young K, Younsi Z, Yu W, Yuan F, Yuan Y, Zensus JA, Zhang S, Zhao G, Zhao S
Publisher: Institute of Physics Publishing
: 2023
: Astrophysical Journal Letters
: The Astrophysical Journal Letters
: L21
: 957
: 2
: 2041-8213
DOI: https://doi.org/10.3847/2041-8213/acff6f
: https://dx.doi.org/10.3847/2041-8213/acff6f
: https://research.utu.fi/converis/portal/detail/Publication/386837063
: https://arxiv.org/abs/2311.10695
The Event Horizon Telescope (EHT) is a millimeter very long baseline interferometry (VLBI) array that has imaged the apparent shadows of the supermassive black holes M87* and Sagittarius A*. Polarimetric data from these observations contain a wealth of information on the black hole and accretion flow properties. In this work, we develop polarimetric geometric modeling methods for mm-VLBI data, focusing on approaches that fit data products with differing degrees of invariance to broad classes of calibration errors. We establish a fitting procedure using a polarimetric “m-ring” model to approximate the image structure near a black hole. By fitting this model to synthetic EHT data from general relativistic magnetohydrodynamic models, we show that the linear and circular polarization structure can be successfully approximated with relatively few model parameters. We then fit this model to EHT observations of M87* taken in 2017. In total intensity and linear polarization, the m-ring fits are consistent with previous results from imaging methods. In circular polarization, the m-ring fits indicate the presence of event-horizon-scale circular polarization structure, with a persistent dipolar asymmetry and orientation across several days. The same structure was recovered independently of observing band, used data products, and model assumptions. Despite this broad agreement, imaging methods do not produce similarly consistent results. Our circular polarization results, which imposed additional assumptions on the source structure, should thus be interpreted with some caution. Polarimetric geometric modeling provides a useful and powerful method to constrain the properties of horizon-scale polarized emission, particularly for sparse arrays like the EHT.
