Black holes are common objects in the universe. Each galaxy contains large numbers-perhaps millions-of stellar-mass black holes, each the remnant of a massive star. In addition, nearly every galaxy contains a supermassive black hole at its center, with a mass ranging from millions to billions of solar masses. This review discusses the demographics of black holes, the ways in which they interact with their environment, factors that may regulate their formation and growth, and progress toward determining whether these objects really warp spacetime as predicted by the general theory of relativity.
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Phys Rev Lett
December 2024
Univ Coimbra, Faculdade de Ciências e Tecnologia da Universidade de Coimbra and CFisUC, Rua Larga, 3004-516 Coimbra, Portugal.
The search for primordial black holes (PBHs) with masses M≪M_{⊙} is motivated by natural early-Universe production mechanisms and that PBHs can be dark matter. For M≲10^{14} kg, the PBH density is constrained by null searches for their expected Hawking emission (HE), the characteristics of which are, however, sensitive to new states beyond the standard model. If there exists a large number of spin-0 particles in nature, PBHs can, through HE, develop and maintain non-negligible spins, modifying the visible HE.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Universidade Federal de Pernambuco, Departamento de Física, 50670-901, Recife, Brazil.
We employ the isomonodromic method to study linear scalar massive perturbations of Kerr black holes for generic scalar masses Mμ and generic black hole spins a/M. We find that the longest-living quasinormal mode and the first overtone coincide for (Mμ)_{c}≃0.370 4981 and (a/M)_{c}≃0.
View Article and Find Full Text PDFPlant Dis
January 2025
LSU AgCenter, Plant Pathology and Crop Physiology, Baton Rouge, Louisiana, United States.
In July 2023, panicle and leaf blight-like symptoms were observed from the rice () variety, PVL03, in research field plots in Louisiana (Rayne, LA 70578, USA; 30.21330⁰ N, 92.37309⁰ W).
View Article and Find Full Text PDFLiving Rev Relativ
January 2025
Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX UK.
In the recent years, primordial black holes (PBHs) have emerged as one of the most interesting and hotly debated topics in cosmology. Among other possibilities, PBHs could explain both some of the signals from binary black hole mergers observed in gravitational-wave detectors and an important component of the dark matter in the Universe. Significant progress has been achieved both on the theory side and from the point of view of observations, including new models and more accurate calculations of PBH formation, evolution, clustering, merger rates, as well as new astrophysical and cosmological probes.
View Article and Find Full Text PDFStud Hist Philos Sci
January 2025
Philosophy Department, Tufts University, United States of America; Black Hole Initiative, Harvard University, United States of America; Lichtenberg Group for History and Philosophy of Physics, University of Bonn, Germany. Electronic address:
In this paper, I provide an account of direct (vs. indirect) detection in gravitational-wave astrophysics. In doing so, I highlight the epistemic considerations that lurk behind existing debates over the application of the term "direct".
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