17 papers
Completing the Penrose Process without a Horizon
Yang Huang, Shiyang Hu, Bin Chen +1
In its standard black-hole realization, the Penrose process uses an event horizon to remove a negative-energy fragment. We show that, at the kinematic level, horizon absorption can…
Novel extended inner shadow in images of Johannsen-Psaltis black holes with thin accretion disks
Xinyu Wang, Xiaobao Wang, Xin-Yang Wang +1
The Johannsen-Psaltis (JP) metric is constructed by introducing deviation parameters into the Kerr metric. The presence of these deviation parameters provides additional degrees of…
Axial Obstructions to Rotating Bumblebee Vacuum Solutions
Minyong Guo, Zhong-Ying Fan
We establish two obstructions to globally regular rotating constant-norm vector vacua. At an axial fixed point of a regular nondegenerate bifurcate Killing horizon, horizon-boost a…
Broadened Lensing Rings of Compact Boson Stars: Enhanced Imprint of Accretion Flow in Images and Visibilities
Xiangyu Wang, Xinyu Wang, Minyong Guo +1
In this work, we systematically study the gravitational lensing properties and observational signatures of compact boson stars. Unlike black holes, the photon effective potential o…
Distorting Kerr Images with Parity-Odd Scalar Hair
Qian Wan, Yehui Hou, Yang Huang +3
We investigate thin-disk imaging of Kerr black holes with synchronized scalar hair, focusing on backreacted parity-odd excited states of a complex scalar field minimally coupled to…
Black Hole Ringdown Seen in Photon Polarization Swings
Jiewei Huang, Yehui Hou, Zhen Zhong +2
Light propagating through a perturbed spacetime could imprint the underlying gravitational waveform directly onto electromagnetic observables. In this Letter, we develop a covarian…