Results 71 to 80 of about 2,296,811 (218)

The formation of supermassive black holes and the evolution of supermassive stars

Classical and Quantum Gravity, 2001
The existence of supermassive black holes is supported by a growing body of observations. Supermassive black holes and their formation events are likely candidates for detection by proposed long-wavelength, space-based gravitational wave interferometers like LISA.
New, Kimberly C. B., Shapiro, Stuart L.
openaire   +3 more sources

Deep Space Network Radio Science and Ground‐Based Planetary Radar in the Next Decade

Radio Science, Volume 60, Issue 7, July 2025.
Abstract The Deep Space Network (DSN) has been a core operational element of NASA's crewed and robotic exploration of the Solar System since the early 1960s. The primary role of the DSN has been to acquire telemetry and navigation data, but over the years, its radiometric and radar capabilities have expanded to form a system for obtaining unique ...
R. S. Park, J. E. Riedel, N. Rodriguez‐Alvarez, M. Brozovic, L. A. M. Benner, P. Vergados, D. Buccino, C. S. Jacobs, L. S. Locke, S. W. Asmar, R. Castano, T. J. W. Lazio, J. Jao, C. Lee   +13 more
wiley   +1 more source

Primordial black holes as supermassive black hole seeds

Journal of Cosmology and Astroparticle Physics
Abstract The presence of supermassive black holes (SMBHs, M • ∼ 10 6-10   M ⊙ ) in the first cosmic Gyr ( z ≳ 6 ...
F. Ziparo, S. Gallerani, A. Ferrara
openaire   +2 more sources

Geodesic Geometry of Black Holes [PDF]

, 2006
The study of geodesics is of intrinsic significance in the study of the geometry of space-time. In this thesis null, space-like and time-like geodesics are studied in the case of the space-times of Schwarzschild, Reissner-Nordstrouml;m and Kerr black ...
Slezakova, Gabriela
core  

Redshift‐Agnostic Machine Learning Classification: Unveiling Peak Performance in Galaxy, Star, and Quasar Classification (Using SDSS DR17)

Astronomische Nachrichten, Volume 346, Issue 5, June 2025.
ABSTRACT Classification of galaxies, stars, and quasars using spectral data is fundamental to astronomy, but often relies heavily on redshift. This study evaluates the performance of 10 machine learning algorithms on SDSS data to classify these objects, with a particular focus on scenarios where redshift information is unavailable.
Debashis Chatterjee, Prithwish Ghosh
wiley   +1 more source

On the hydrodynamic interplay between a young nuclear starburst and a central supermassive black hole [PDF]

, 2010
We present one-dimensional numerical simulations, which consider the effects of radiative cooling and gravity on the hydrodynamics of the matter reinserted by stellar winds and supernovae within young nuclear starbursts (NSBs) with a central supermassive
GUILLERMO TENORIO TAGLE, Filiberto Hueyotl Zahuantitla, SERGIY SILICH   +2 more
core  

Stochastic Quantum Mechanics in Curved Spaces: Application to Schwarzschild Black Holes

Astronomische Nachrichten, Volume 346, Issue 3-4, March-May 2025.
ABSTRACT In this work, we start from the hypothesis that the universe lives in a Gravitational Wave Background (GWB). From this hypothesis, it follows that space–time is not locally flat because we have to take into account the fluctuations of the GWB in space–time. This implies that sufficiently small particles will feel these oscillations, preventing
Juan S. Jerez‐Rodriguez, Tonatiuh Matos   +1 more
wiley   +1 more source

Powerful Radio Sources as Probes of Black Hole Physics

Universe
Powerful jetted radio sources for which the luminosity in directed kinetic energy has been empirically determined, independent of assumptions, are considered.
Ruth A. Daly
doaj   +1 more source

Null Geodesics and Strong Field Gravitational Lensing in a String Cloud Background

Advances in High Energy Physics, 2015
This paper is devoted to studying two interesting issues of a black hole with string cloud background. Firstly, we investigate null geodesics and find unstable orbital motion of particles. Secondly, we calculate deflection angle in strong field limit. We
M. Sharif, Sehrish Iftikhar
doaj   +1 more source

Interplay of Magnetic Reconnection and Current Sheet Kink Instability in the Earth's Magnetotail

Geophysical Research Letters, Volume 52, Issue 2, 28 January 2025.
Abstract Magnetic reconnection and current sheet kink instability often develop concurrently in current sheets, yet their dynamic interplay remains unclear. We investigate their interaction in the magnetotail of a 3D global magnetospheric hybrid‐Vlasov simulation. We identify the instability growth and saturation phase and estimate the evolution of the
G. Cozzani, M. Alho, I. Zaitsev, H. Zhou, S. Hoilijoki, L. Turc, M. Grandin, K. Horaites, M. Battarbee, Y. Pfau‐Kempf, U. Ganse, K. Papadakis, M. Palmroth   +12 more
wiley   +1 more source