Bumblebee Black Holes in Light of Event Horizon Telescope Observations

Abstract

We report the existence of novel static spherical black hole solutions in a vector–tensor gravitational theory called the bumblebee gravity model, which extends the Einstein–Maxwell theory by allowing the vector to nonminimally couple to the Ricci curvature tensor. A test of the solutions in the strong-field regime is performed for the first time using the recent observations of the supermassive black hole shadows in the galaxy M87 and the Milky Way from the Event Horizon Telescope Collaboration. The parameter space is found largely unexcluded and more experiments are needed to fully bind the theory.

Probing the vector charge of Sagittarius A* with pulsar timing

“…Although current observations with EHT and thermodynamic consideration of the bumblebee BHs only set loose constraints on Q/M for Sgr A* even for the case that ξ deviates from 2κ significantly [31,33,39], it turns out that the prospective measurement precision of Q/M using pulsar timing can be as small as Q/M ∼ O(10 −2 ) for |ξ/2κ − 1| ≳ 1 as we will find out later. Moreover, from eqs.…”

“…We first constructed a timing model based on the fully numerical calculations of the BH metric, light propagation, and pulsar orbital motion in the bumblebee gravity. Considering the future timing precision for such GC pulsars and current constraints on the bumblebee charge of Sgr A* [31,33], we also constructed a timing model only including the leading order effects based on the expansion solution of the metric that is more efficient and flexible than the fully numerical approach. Our simulation shows that for a pulsar with an orbital period P b ∼ 0.5 yr, an orbital eccentricity e ∼ 0.8, a 5-yr observation with weekly recorded TOAs, and a timing precision of 1 ms, one can constrain the bumblebee charge of Sgr A* to be ∼ O(10 −3 -10 −2 ) for |ξ/2κ−1| ≳ 1, which is much better than the current constraints from the EHT observation [33], and at the same order of magnitude as the expected constraint from the extreme-mass-ratio inspiral observation with the Laser Interferometer Space Antenna (LISA) [34].…”

“…The bumblebee gravity model has been widely studied in the literature as an example for spontaneous violation of the Lorentz symmetry or for being a simple extension of the Einstein-Maxwell theory [28][29][30][31]. While observations in the Solar System set stringent constraints on the bumblebee gravity in the weak-field region [31,32], recent studies using the BH shadows observed by the Event Horizon Telescope (EHT) leave a large parameter space in the strong-field region untested [31,33]. Considering the high precision of pulsar timing experiments, the main purpose of this work is to develop a timing model for pulsar-SMBH systems in the bumblebee gravity theory and to investigate the potential of constraining the bumblebee gravity with future timing observations.…”

Exploring antisymmetric tensor effects on black hole shadows and quasinormal frequencies

“…Additionally, Xu et al introduced innovative categories of static spherical bumblebee black holes by incorporating a background bumblebee field with a non-zero temporal component, exploring their thermodynamic characteristics and observational consequences in refs. [39][40][41][42].…”

Zhuzhou Haichuan Industrial Co., Ltd. v. Changsha Cai'e Subbranch of Bank of China Limited, Hunan Deyihong Metal Materials Co., Ltd.

“…Subsequently, various spherically symmetric solutions in bumblebee gravity were found [17][18][19][20][21], while the first exact rotating bumblebee solution was derived by Poulis et al [22]. Building on these solutions, LSB has become an active area in black hole physics [23][24][25][26][27][28][29][30][31][32][33].…”