Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2105.09343

Constraints on black-hole charges with the 2017 EHT observations of M87*

Prashant Kocherlakota·Luciano Rezzolla·Heino Falcke·Christian M. Fromm·Michael Kramer·Yosuke Mizuno·Antonios Nathanail·Hector Olivares·Ziri Younsi·Kazunori Akiyama·Antxon Alberdi·Walter Alef·Juan Carlos Algaba·Richard Anantua·Keiichi Asada·Rebecca Azulay·Anne-Kathrin Baczko·David Ball·Mislav Balokovic·John Barrett·Bradford A. Benson·Dan Bintley·Lindy Blackburn·Raymond Blundell·Wilfred Boland·Katherine L. Bouman·Geoffrey C. Bower·Hope Boyce·Michael Bremer·Christiaan D. Brinkerink·Roger Brissenden·Silke Britzen·Avery E. Broderick·Dominique Broguiere·Thomas Bronzwaer·Do-Young Byun·John E. Carlstrom·Andrew Chael·Chi-kwan Chan·Shami Chatterjee·Koushik Chatterjee·Ming-Tang Chen·Yongjun Chen·Paul M. Chesler·Ilje Cho·Pierre Christian·John E. Conway·James M. Cordes·Thomas M. Crawford·Geoffrey B. Crew·Alejandro Cruz-Osorio·Yuzhu Cui·Jordy Davelaar·Mariafelicia De Laurentis·Roger Deane·Jessica Dempsey·Gregory Desvignes·Sheperd S. Doeleman·Ralph P. Eatough·Joseph Farah·Vincent L. Fish·Ed Fomalont·Raquel Fraga-Encinas·Per Friberg·H. Alyson Ford·Antonio Fuentes·Peter Galison·Charles F. Gammie·Roberto Garcia·Olivier Gentaz·Boris Georgiev·Ciriaco Goddi·Roman Gold·Jose L. Gomez·Arturo I. Gomez-Ruiz·Minfeng Gu·Mark Gurwell·Kazuhiro Hada·Daryl Haggard·Michael H. Hecht·Ronald Hesper·Luis C. Ho·Paul Ho·Mareki Honma·Chih-Wei L. Huang·Lei Huang·David H. Hughes·Shiro Ikeda·Makoto Inoue·Sara Issaoun·David J. James·Buell T. Jannuzi·Michael Janssen·Britton Jeter·Wu Jiang·Alejandra Jimenez-Rosales·Michael D. Johnson·Svetlana Jorstad·Taehyun Jung·Mansour Karami
View original source ↗Read source document ↗Export metadata ↓

Abstract

Our understanding of strong gravity near supermassive compact objects has recently improved thanks to the measurements made by the Event Horizon Telescope (EHT). We use here the M87* shadow size to infer constraints on the physical charges of a large variety of nonrotating or rotating black holes. For example, we show that the quality of the measurements is already sufficient to rule out that M87* is a highly charged dilaton black hole. Similarly, when considering black holes with two physical and independent charges, we are able to exclude considerable regions of the space of parameters for the doubly-charged dilaton and the Sen black holes.

Explore related subjects

gr-qc

Keep this discovery

BibTeXRIS

Prashant Kocherlakota, Luciano Rezzolla, Heino Falcke, Christian M. Fromm, Michael Kramer, Yosuke Mizuno, Antonios Nathanail, Hector Olivares, Ziri Younsi, Kazunori Akiyama, Antxon Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, Keiichi Asada, Rebecca Azulay, Anne-Kathrin Baczko, David Ball, Mislav Balokovic, John Barrett, Bradford A. Benson, Dan Bintley, Lindy Blackburn, Raymond Blundell, Wilfred Boland, Katherine L. Bouman, Geoffrey C. Bower, Hope Boyce, Michael Bremer, Christiaan D. Brinkerink, Roger Brissenden, Silke Britzen, Avery E. Broderick, Dominique Broguiere, Thomas Bronzwaer, Do-Young Byun, John E. Carlstrom, Andrew Chael, Chi-kwan Chan, Shami Chatterjee, Koushik Chatterjee, Ming-Tang Chen, Yongjun Chen, Paul M. Chesler, Ilje Cho, Pierre Christian, John E. Conway, James M. Cordes, Thomas M. Crawford, Geoffrey B. Crew, Alejandro Cruz-Osorio, Yuzhu Cui, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, Gregory Desvignes, Sheperd S. Doeleman, Ralph P. Eatough, Joseph Farah, Vincent L. Fish, Ed Fomalont, Raquel Fraga-Encinas, Per Friberg, H. Alyson Ford, Antonio Fuentes, Peter Galison, Charles F. Gammie, Roberto Garcia, Olivier Gentaz, Boris Georgiev, Ciriaco Goddi, Roman Gold, Jose L. Gomez, Arturo I. Gomez-Ruiz, Minfeng Gu, Mark Gurwell, Kazuhiro Hada, Daryl Haggard, Michael H. Hecht, Ronald Hesper, Luis C. Ho, Paul Ho, Mareki Honma, Chih-Wei L. Huang, Lei Huang, David H. Hughes, Shiro Ikeda, Makoto Inoue, Sara Issaoun, David J. James, Buell T. Jannuzi, Michael Janssen, Britton Jeter, Wu Jiang, Alejandra Jimenez-Rosales, Michael D. Johnson, Svetlana Jorstad, Taehyun Jung, Mansour Karami. 2021-05-19. Constraints on black-hole charges with the 2017 EHT observations of M87*. https://doi.org/10.1103/physrevd.103.104047

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Electrovacuum Black Hole Uniqueness

We prove the black hole uniqueness conjecture in the axially symmetric, stationary, electrovacuum setting, subject to the refined asymptotic analysis of the associated singular harmonic maps, which includes an analyticity hypothesis at the axes. More precisely, it is shown that any asymptotically flat solution of the Einstein--Maxwell equations in this class, with more than one black hole horizon component is either: Majumdar--Papapetrou, up to a duality rotation, in which case all logarithmic angle defects vanish, or every finite axis rod logarithmic angle defect is strictly negative and hence every interaction force is strictly attractive. The proof extends the singular harmonic map method used for vacuum Kerr uniqueness in [18].

gr-qc↗
arXiv2026

Constraining Modified Mass-to-Horizon Cosmology Through Primordial Inflationary Observables

We investigate slow-roll inflation in a modified cosmological framework inspired by a generalized mass-to-horizon relation (MHR), $M=\gamma {c^2 L^n}/{G}$, where $n$ is a real parameter and $\gamma$ a dimensional constant. Using Padmanabhan's emergence paradigm, we derive the modified Friedmann equations for a flat FRW universe and analyze the dynamics of a canonical scalar field (inflaton) under the slow-roll approximation. We study the resulting inflationary phenomenology for power-law and Starobinsky potentials. For power-law potentials, the MHR modification fails to reconcile these models with current CMB constraints on $r$ and $n_s$. In contrast, Starobinsky inflation exhibits significant sensitivity to deviations from $n=1$. A perturbative analysis ($n=1+\Delta$) yields corrections to inflationary observables. We observe that the scalar power-spectrum normalization, under a fixed-Starobinsky prescription, imposes the stringent constraint $0.960 \lesssim n \lesssim 1.040$ for $N=60$ efolds. This is considerably tighter than spectral-index bounds. Our results establish inflation, particularly Starobinsky-like models, as a sensitive probe of generalized horizon thermodynamics and departures from standard MHR scaling.

gr-qc↗
arXiv2026

Improving the Sensitivity of Gravitational Wave Detection with Weighted Conformal Prediction

In the last decade, kilometre-scale interferometric gravitational-wave detectors have observed hundreds of compact binary mergers, the majority of which are binary black holes. However, the data are noise-dominated, and multiple independent search algorithms (pipelines) are used to enhance sensitivity and improve robustness. Rather than the standard approach of selecting the most significant pipeline output, we combine the outputs from all pipelines using a conformal prediction-based framework to provide statistically rigorous confidence estimates for candidate events. While combining pipelines improves sensitivity and ranking robustness, it requires a principled statistical framework that remains valid as data properties evolve across observing runs. A key challenge is distribution shifts between simulated datasets used for training and calibration and the real, unlabelled, observations used for testing, which can invalidate coverage guarantees and bias confidence estimates. In this work, we address this challenge by incorporating likelihood-ratio reweighting into our conformal prediction framework to account for covariate shift. Using mock datasets containing simulated signals, we demonstrate that weighted conformal prediction restores well-calibrated coverage under covariate shift and increases the confidence of events near the detection threshold, recovering true signals that would otherwise be missed.

gr-qc↗