Constraining the charge of the Galactic centre black hole

verfasst von: Michal Zajaček, Arman Tursunov, Andreas Eckart, Silke Britzen, Eva Hackmann, Vladimír Karas, Zdeněk Stuchlík, Bozena Czerny, J. Anton Zensus
Abstract: In this contribution, we summarize our results concerning the observational constraints on the electric charge associated with the Galactic centre black hole - Sgr A∗. According to the no-hair theorem, every astrophysical black hole, including supermassive black holes, is characterized by at most three classical, externally observable parameters - mass, spin, and the electric charge. While the mass and the spin have routinely been measured by several methods, the electric charge has usually been neglected, based on the arguments of efficient discharge in astrophysical plasmas. From a theoretical point of view, the black hole can attain charge due to the mass imbalance between protons and electrons in fully ionized plasmas, which yields about ∼ 10⁸ C for Sgr A∗. The second, induction mechanism concerns rotating Kerr black holes embedded in an external magnetic field, which leads to electric field generation due to the twisting of magnetic field lines. This electric field can be associated with the induced Wald charge, for which we calculate the upper limit of ∼ 10¹⁵ C for Sgr A∗. Although the maximum theoretical limit of ∼ 10¹⁵ C is still 12 orders of magnitude smaller than the extremal charge of Sgr A∗, we analyse a few astrophysical consequences of having a black hole with a small charge in the Galactic centre. Two most prominent ones are the effect on the X-ray bremsstrahlung profile and the effect on the position of the innermost stable circular orbit.
Externe Organisation(en): Max-Planck-Institut für Radioastronomie (MPIfR)
Universität zu Köln
Silesian University in Opava
Akademie Věd České Republiky (AV ČR)
Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM)
Polish Academy of Sciences (PASIFIC)
Typ: Konferenzaufsatz in Fachzeitschrift
Journal: Journal of Physics: Conference Series
Band: 1258
Anzahl der Seiten: 17
ISSN: 1742-6588
Publikationsdatum: 21.10.2019
Publikationsstatus: Veröffentlicht
Peer-reviewed: Ja
ASJC Scopus Sachgebiete: Physik und Astronomie (insg.)
Elektronische Version(en): https://doi.org/10.48550/arXiv.1812.03574 (Zugang: Offen)
https://doi.org/10.1088/1742-6596/1258/1/012031 (Zugang: Offen)

BibTeX

@article{1733e61661944de7a22888d64a3ee89e,
title = "Constraining the charge of the Galactic centre black hole",
abstract = "In this contribution, we summarize our results concerning the observational constraints on the electric charge associated with the Galactic centre black hole - Sgr A∗. According to the no-hair theorem, every astrophysical black hole, including supermassive black holes, is characterized by at most three classical, externally observable parameters - mass, spin, and the electric charge. While the mass and the spin have routinely been measured by several methods, the electric charge has usually been neglected, based on the arguments of efficient discharge in astrophysical plasmas. From a theoretical point of view, the black hole can attain charge due to the mass imbalance between protons and electrons in fully ionized plasmas, which yields about ∼ 108 C for Sgr A∗. The second, induction mechanism concerns rotating Kerr black holes embedded in an external magnetic field, which leads to electric field generation due to the twisting of magnetic field lines. This electric field can be associated with the induced Wald charge, for which we calculate the upper limit of ∼ 1015 C for Sgr A∗. Although the maximum theoretical limit of ∼ 1015 C is still 12 orders of magnitude smaller than the extremal charge of Sgr A∗, we analyse a few astrophysical consequences of having a black hole with a small charge in the Galactic centre. Two most prominent ones are the effect on the X-ray bremsstrahlung profile and the effect on the position of the innermost stable circular orbit.",
author = "Michal Zaja{\v c}ek and Arman Tursunov and Andreas Eckart and Silke Britzen and Eva Hackmann and Vladim{\'i}r Karas and Zden{\v e}k Stuchl{\'i}k and Bozena Czerny and Zensus, {J. Anton}",
note = "Publisher Copyright: {\textcopyright} 2019 IOP Publishing Ltd. All rights reserved.; 1st Sharjah International Conference on Particle Physics, Astrophysics and Cosmology, FISICPAC 2018 ; Conference date: 11-11-2018 Through 13-11-2018",
year = "2019",
month = oct,
day = "21",
doi = "10.48550/arXiv.1812.03574",
language = "English",
volume = "1258",
journal = "Journal of Physics: Conference Series",
issn = "1742-6588",
publisher = "IOP Publishing Ltd.",
number = "1",
}