Results 41 to 50 of about 2,068 (181)

The cosmological ultra-low frequency radio background: a solution to the Hubble tension and the 21-cm excess trough

European Physical Journal C: Particles and Fields, 2023
Recent observations of the Cosmic Microwave Background and the Hubble Space Telescope obtain two different values of the Hubble constant with a discrepancy of at least $$4.4 \sigma $$ 4.4 σ , which is now known as the Hubble tension.
Man Ho Chan
doaj   +1 more source

Mastcam‐Z Spectrophotometric Properties of Materials at the Van Zyl Overlook, Jezero Crater

Journal of Geophysical Research: Planets, Volume 131, Issue 6, June 2026.
Abstract During Sols 63–65 of Mars 2020, Mastcam‐Z multispectral (442–1022 nm) images were acquired at Van Zyl Overlook (VZO), spanning phase angles from ∼0° to 150°, to model photometric parameters for seven surface units. These units included rocks, soils, regolith, and rover tracks near the Jezero landing site.
B. Margara, J. R. Johnson, A. G. Hayes, M. T. Lemmon, W. M. Grundy, J. F. Bell III, M. N. Barrington   +6 more
wiley   +1 more source

Faint White Dwarf Flux Standards: Data and Models

The Astronomical Journal
Fainter standard stars are essential for the calibration of larger telescopes. This work adds to the calibration spectra (CALSPEC) database of 19 faint white dwarfs (WDs) with all-sky coverage and V magnitudes between 16.5 and 18.7.
Ralph C. Bohlin, Susana Deustua, Gautham Narayan, Abhijit Saha, Annalisa Calamida, Karl D. Gordon, Jay B. Holberg, Ivan Hubeny, Thomas Matheson, Armin Rest   +9 more
doaj   +1 more source

Thermal Escape of Atomic Hydrogen on Mars: A Comprehensive View With a General Circulation Model

Journal of Geophysical Research: Planets, Volume 131, Issue 6, June 2026.
Abstract Mars loses water mainly through the photodissociation of water vapor, followed by the thermal escape of light hydrogen atoms. Observations have revealed large seasonal variations in hydrogen concentration in the upper thermosphere, peaking during southern summers and intensifying during dust storms.
Alexander S. Medvedev, Ngan H. D. Trinh
wiley   +1 more source

Echoes in the Noise: Posterior Samples of Faint Galaxy Surface Brightness Profiles with Score-based Likelihoods and Priors

The Astronomical Journal
Examining the detailed structure of galaxy populations provides valuable insights into their formation and evolution mechanisms. Significant barriers to such analysis are the nontrivial noise properties of real astronomical images and the point-spread ...
Alexandre Adam, Connor Stone, Connor Bottrell, Ronan Legin, Yashar Hezaveh, Laurence Perreaul-Levasseur   +5 more
doaj   +1 more source

Massive Star Formation in the Ultraviolet Observed with the Hubble Space Telescope

Galaxies, 2020
Spectroscopic observations of a massive star formation in the ultraviolet and their interpretation are reviewed. After a brief historical retrospective, two well-studied resolved star clusters and the surrounding H II regions are introduced: NGC 2070 in ...
Claus Leitherer
doaj   +1 more source

Beyond the Hubble Space Telescope [PDF]

Nature, 1996
NASA needs to develop a new generation of space observatories embracing the theme of 'cosmic origins' if it is to maintain its lead in the exploration of space.
Thronson, H. A., Dressler, A., Richstone, Douglas O.   +2 more
openaire   +2 more sources

Status and Prospect of Secondary Battery Technologies in Space Applications: Challenges and the Future

Batteries &Supercaps, Volume 9, Issue 5, May 2026.
Lithium‐ion batteries used in space applications are exposed to extreme conditions, including radiation, vacuum, wide temperature fluctuations, and long storage times, all of which accelerate degradation. This review article summarizes the main degradation mechanisms affecting battery performance in space environments, including capacity fade ...
Xunkai Chen, Kelsey B. Hatzell
wiley   +1 more source

A New Approach to Compiling Exoatmospheric Target Lists and Quantifying the Ground-based Resources Needed to Vet Them

The Astronomical Journal
Transiting exoplanet atmospheric characterization is currently in a golden age as dozens of exoplanet atmospheres are being studied by NASA’s Hubble and James Webb Space Telescopes.
Jennifer A. Burt, Robert T. Zellem, David R. Ciardi, Shubham Kanodia, Geoffrey Bryden, Tiffany Kataria, Kyle A. Pearson, Jessie L. Christiansen, Charles Beichman, B. J. Fulton, Mark Swain   +10 more
doaj   +1 more source

Constraining Electron‐Impact Ionization of O2 Through UV Aurora Observations at Ganymede

Journal of Geophysical Research: Space Physics, Volume 131, Issue 5, May 2026.
Abstract While photoionization rates of Ganymede's O2 ${\mathrm{O}}_{2}$ dominated atmosphere are well constrained, the contribution of electron‐impact ionization is rather uncertain. Previous quantitative estimates have relied on assumptions about densities and energy distributions of precipitating electrons, or on rare spacecraft measurements that ...
Stefan Duling, Joachim Saur, Darrell Strobel, Philippa Molyneux, Jamey R. Szalay, Thomas K. Greathouse   +5 more
wiley   +1 more source