Results 61 to 70 of about 2,068 (181)

Late-time acceleration with steep exponential potentials

European Physical Journal C: Particles and Fields, 2017
In this letter, we study the cosmological dynamics of steeper potential than exponential. Our analysis shows that a simple extension of an exponential potential allows to capture late-time cosmic acceleration and retain the tracker behavior.
M. Shahalam, Weiqiang Yang, R. Myrzakulov, Anzhong Wang   +3 more
doaj   +1 more source

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

The Importance of Optical Wavelength Data on Atmospheric Retrievals of Exoplanet Transmission Spectra

The Astronomical Journal
Exoplanet transmission spectra provide rich information about the chemical composition, clouds, and temperature structure of exoplanet atmospheres. Most exoplanet transmission spectra only span infrared wavelengths (≳1 μ m), which can preclude crucial ...
Charlotte Fairman, Hannah R. Wakeford, Ryan J. MacDonald   +2 more
doaj   +1 more source

Status Report on the Chicago-Carnegie Hubble Program (CCHP): Measurement of the Hubble Constant Using the Hubble and James Webb Space Telescopes

The Astrophysical Journal
We present the latest results from the Chicago-Carnegie Hubble Program to measure the Hubble constant, using data from the James Webb Space Telescope (JWST). The overall program aims to calibrate three independent methods: (1) tip of the red giant branch
Wendy L. Freedman, Barry F. Madore, Taylor J. Hoyt, In Sung Jang, Abigail J. Lee, Kayla A. Owens   +5 more
doaj   +1 more source

Hubble Space Telescope proper motions of Large Magellanic Cloud star clusters

Astronomy & Astrophysics
In this paper, we explore the kinematic properties of a sample of 19 young (
Niederhofer F., Cullinane L., Massari D., Bastian N., Bellini A., Aguado-Agelet F., Cassisi S., Erkal D., Libralato M., Kacharov N., Cabrera-Ziri I., Ceccarelli E., Cioni M.-R. L., Dresbach F., Häberle M., Martocchia S., Saracino S.   +16 more
doaj   +1 more source

A Snapshot Survey of Nearby Supernovae with the Hubble Space Telescope

The Astrophysical Journal
Over recent decades, robotic (or highly automated) searches for supernovae (SNe) have discovered several thousand events, many of them in quite nearby galaxies (distances < 30 Mpc).
Raphael Baer-Way, Asia DeGraw, WeiKang Zheng, Schuyler D. Van Dyk, Alexei V. Filippenko, Ori D. Fox, Thomas G. Brink, Patrick L. Kelly, Nathan Smith, Sergiy S. Vasylyev, Thomas de Jaeger, Keto Zhang, Samantha Stegman, Timothy Ross, Sameen Yunus   +14 more
doaj   +1 more source

Zonal and Regional Jupiter Brightness Trends from the Hubble Outer Planet Atmospheres Legacy Program

The Planetary Science Journal
The Hubble Outer Planet Atmospheres Legacy program began in 2014 and has observed Jupiter yearly from 2015 to 2024. Using high spatial resolution imaging from the Hubble Wide Field Camera 3, brightness trends were investigated focusing on the unique UV ...
Amy A. Simon, Michael H. Wong
doaj   +1 more source

Spitzer + Hubble Space Telescope Parallaxes of 13 Late T and Y Dwarfs

The Astronomical Journal
We present astrometric measurements for 13 cold brown dwarfs in the solar neighborhood ( d  
Federico Marocco, J. Davy Kirkpatrick, Richard L. Smart, Adam C. Schneider, Dan Caselden, Edgardo Costa, Michael C. Cushing, Maximiliano Dirk, Peter R. M. Eisenhardt, Jacqueline K. Faherty, Christopher R. Gelino, Marc J. Kuchner, Aaron M. Meisner, Rene A. Mendez, Robert A. Stiller, Edward L. Wright   +15 more
doaj   +1 more source

New Estimates of Nitrogen Fixation on Early Earth

Life
Fixed nitrogen species generated by the early Earth’s atmosphere are thought to be critical to the emergence of life and the sustenance of early metabolisms.
Madeline Christensen, Danica Adams, Michael L. Wong, Patrick Dunn, Yuk L. Yung   +4 more
doaj   +1 more source

JWST Observations Reject Unrecognized Crowding of Cepheid Photometry as an Explanation for the Hubble Tension at 8σ Confidence

The Astrophysical Journal Letters
We present high-definition observations with the James Webb Space Telescope (JWST) of >1000 Cepheids in a geometric anchor of the distance ladder, NGC 4258, and in five hosts of eight Type Ia supernovae, a far greater sample than previous studies with ...
Adam G. Riess, Gagandeep S. Anand, Wenlong Yuan, Stefano Casertano, Andrew Dolphin, Lucas M. Macri, Louise Breuval, Dan Scolnic, Marshall Perrin, Richard I. Anderson   +9 more
doaj   +1 more source