Results 71 to 80 of about 114,518 (203)

The Ups and Downs of the Hubble Constant

, 2005
A brief history of the determination of the Hubble constant H_0 is given. Early attempts following Lemaitre (1927) gave much too high values due to errors of the magnitude scale, Malmquist bias and calibration problems.
Tammann, G. A.
core   +1 more source

Causal Bulk Viscous Dissipative Isotropic Cosmologies with Variable Gravitational and Cosmological Constants [PDF]

, 2001
We consider the evolution of a flat Friedmann-Robertson-Walker Universe, filled with a causal bulk viscous cosmological fluid, in the presence of variable gravitational and cosmological constants. The basic equation for the Hubble parameter, generalizing
Abdel-Rahman A.-M. M., Arbab A. I., Barrow J. D., Beesham A., Berman M. S., Carvalho J. C., Chen W., Coley A. A., Di Prisco A., Hiscock W. A., J. A. BELINCHÓN, Lima J. A. S., Lima J. A. S., M. K. MAK, Maartens R., Mak M. K., Mak M. K., Mak M. K., Overduin J. M., T. HARKO   +19 more
core   +2 more sources

Motional Induction in Ganymede's Ocean

Geophysical Research Letters, Volume 53, Issue 6, 28 March 2026.
Abstract We investigate the magnetic signature of oceanic circulation in Ganymede's subsurface ocean using kinematic induction modeling. Our approach couples zonal jet flows from rotating thermal convection simulations with magnetic field models incorporating Ganymede's internal dynamo and external contributions from Jupiter.
Simon Cabanes, Thomas Gastine, Alexandre Fournier   +2 more
wiley   +1 more source

Construction of the cosmological model with periodically distributed inhomogeneities with growing amplitude

European Physical Journal C: Particles and Fields, 2021
We construct an approximate solution to the cosmological perturbation theory around Einstein–de Sitter background up to the fourth-order perturbations. This could be done with the help of the specific symmetry condition imposed on the metric, from which ...
Szymon Sikora, Krzysztof Głód
doaj   +1 more source

Hubble Constant, Lensing, and Time Delay in Relativistic MOND

, 2013
Time delay in galaxy gravitational lensing systems has been used to determine the value of Hubble constant. As in other dynamical phenomena at the scale of galaxy, dark matter is often invoked in gravitational lensing to account for the "missing mass ...
Chiu, Mu-Chen, Ko, Chung-Ming, Tian, Yong   +2 more
core   +1 more source

A Redetermination of the Hubble Constant with the Hubble Space Telescope from a Differential Distance Ladder [PDF]

, 2009
We report observations of 240 Cepheid variables obtained with the Near Infrared Camera (NICMOS) through the F160W filter on the Hubble Space Telescope (HST).
Adam G. Riess, Albrecht, Alexei V. Filippenko, Benedict, Berdnikov, Bergeron, Bird, Braatz, Bushouse, Conley, Davis, de Jong, Devdeep Sarkar, Fitzpatrick, Freedman, Gibson, Greenhill, Hatano, Henry C. Ferguson, Hicken, Hu, Hubert Lampeitl, Humphreys, Humphreys, Jha, Jha, Kessler, Komatsu, Kowalski, Leonard, Lucas Macri, Macri, Macri, Macri, Marconi, Megan Sosey, Perlmutter, Persson, Phillips, Riess, Riess, Riess, Riess, Riess, Riess, Ryan Chornock, Saha, Saha, Sandage, Sarkar, Saurabh W. Jha, Sebo, Seo, Spergel, Stefano Casertano, Sullivan, Suntzeff, Visser, Weidong Li, Wood-Vasey, Zehavi   +60 more
core   +4 more sources

Auroral Emissions on Ganymede: New Constraints on Their Electron Energy Dependence

Geophysical Research Letters, Volume 53, Issue 6, 28 March 2026.
Abstract Auroral emissions on Ganymede provide critical insights into its magnetospheric dynamics and atmospheric composition. Using a physics‐based atmospheric model with recent atmospheric observations and laboratory measurements of electron‐impact cross‐sections, this study revisits and significantly refines the relationship between auroral emission
Xin Cao, Mika K. G. Holmberg, Caitriona M. Jackman, Hans L. F. Huybrighs, Sebastian Cervantes, Audrey Vorburger   +5 more
wiley   +1 more source

Steady Collapse of Uranus' Exosphere After 1998 to the Present Decade

Geophysical Research Letters, Volume 53, Issue 6, 28 March 2026.
Abstract Uranus' thermospheric temperature decreased from ∼800K in 1986 to ∼450K in 2022 as determined from observations of H3+ and H2 infrared emissions. Spitzer 2007 lower atmosphere observations do not emulate this cooling trend. Here we show that the atomic H Lyman ⍺ emission from the disk of Uranus observed by HST from 2011 to 2022 are not ...
D. Bhattacharyya, J. T. Clarke, P. Stephenson, T. Koskinen, J.‐Y. Chaufray, L. Moore, H. Melin   +6 more
wiley   +1 more source

Mitigating the Binary Viewing Angle Bias for Standard Sirens

The Astrophysical Journal Letters
The inconsistency between experiments in the measurements of the local Universe expansion rate, the Hubble constant, suggests unknown systematics in the existing experiments or new physics.
Alberto Salvarese, Hsin-Yu Chen
doaj   +1 more source

The Hubble constant and dark energy from cosmological distance measures

, 2008
We study how the determination of the Hubble constant from cosmological distance measures is affected by models of dark energy and vice versa. For this purpose, constraints on the Hubble constant and dark energy are investigated using the cosmological ...
, Bonamente M Joy M K La Roque S J Carlstrom J E Reese E D Dawson K S, Brent R P, Clarkson C, Davis T M, Dick J, Doran M, Elgaroy O Multamaki T, Gong Y Wu Q Wang A, Ichikawa K, Ichikawa K, Jackson N, Kazuhide Ichikawa, Press W H, Rapetti D Allen S W, Riess A G, Tomo Takahashi, Wang Y Mukherjee P, Wood-Vasey W M, Wright E L   +19 more
core   +2 more sources