Results 31 to 40 of about 210 (157)

The HETDEX Survey Emission-line Exploration and Source Classification

The Astrophysical Journal, 2023
The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) is an untargeted spectroscopic survey that aims to measure the expansion rate of the universe at z ∼ 2.4 to 1% precision for both H ( z ) and D _A ( z ).
Dustin Davis, Karl Gebhardt, Erin Mentuch Cooper, Robin Ciardullo, Maximilian Fabricius, Daniel J. Farrow, John J. Feldmeier, Steven L. Finkelstein, Eric Gawiser, Caryl Gronwall, Gary J. Hill, Ulrich Hopp, Lindsay R. House, Donghui Jeong, Wolfram Kollatschny, Eiichiro Komatsu, Martin Landriau, Chenxu Liu, Shun Saito, Sarah Tuttle, Isak G. B. Wold, Gregory R. Zeimann, Yechi Zhang   +22 more
doaj   +1 more source

Dynamical Dark Sector: A Joint Two‐Scalar‐Field Model for Dark Matter and Quintessence

Advances in Astronomy, Volume 2026, Issue 1, 2026.
The physical nature of dark matter and dark energy remains one of the most pressing questions in modern cosmology. This work presents a phenomenological model where the entire dark sector is described by two minimally coupled scalar fields within general relativity.
Silvio A. Corrêa Junior, Jianguo Yan
wiley   +1 more source

Constraints on the z  ∼  6−13 intergalactic medium from JWST spectroscopy of Lyman-alpha damping wings in galaxies

Astronomy & Astrophysics
Context. JWST provides a unique dataset for studying the earliest stages of reionisation at z > 9, promising insights into the first galaxies. Many JWST/NIRSpec prism spectra of z > 5 galaxies have revealed smooth Lyman-alpha breaks, implying damping ...
Mason Charlotte A., Chen Zuyi, Stark Daniel P., Yi Lu Ting, Topping Michael, Tang Mengtao   +5 more
doaj   +1 more source

Approximation of Daily AMS‐02 Spectra With Machine Learning Methods

Journal of Geophysical Research: Machine Learning and Computation, Volume 2, Issue 4, December 2025.
Abstract Almost three thousand daily AMS‐02 proton spectra from 2011 to 2019 offer the most precise and extensive data set of cosmic ray spectra covering a wide energy range. As such, they offer a unique opportunity to test machine learning algorithms for approximating cosmic ray proton spectra based on the inputs usually available to solar modulation ...
Martin Nguyen, Pavol Bobík, Ján Genči
wiley   +1 more source

HOW LYMAN ALPHA EMISSION DEPENDS ON GALAXY STELLAR MASS [PDF]

The Astrophysical Journal Letters, 2016
ABSTRACT In this work, we show how the stellar mass (M *) of galaxies affects the 3 < z < 4.6 Lyα equivalent width (EW) distribution. To this end, we design a sample of 629 galaxies in the M * range from the ...
Grecco A. Oyarzún, Guillermo A. Blanc, Valentino González, Mario Mateo, John I. Bailey III, Steven L. Finkelstein, Paulina Lira, Jeffrey D. Crane, Edward W. Olszewski   +8 more
openaire   +3 more sources

Solar Flare Activity, 1937–2024: Introducing the New Hemispheric Solar Flare Index (hSFI) in the Context of 2024's Major Solar Storm Events

Space Weather, Volume 23, Issue 11, November 2025.
Abstract A new daily composite of the solar flare index (SFI) and the hemispherically‐resolved versions (hSFI) are presented for 1937 to 2024. The data set confirms that the northern hemisphere (NH) dominated solar flare activity during Solar Cycles 17 to 21, but that the southern hemisphere has dominated from Solar Cycle 22 to present.
V. M. Velasco Herrera, W. Soon, S. Knoška, A. Özgüç, G. Velasco Herrera, H. Yeşilyaprak, N. Babynets, M. Švanda, J. Muraközy, S. Qiu, D. Riveros‐Rosas, R. Connolly, M. Connolly, A. Tlatov, L. Cappellotto   +14 more
wiley   +1 more source

The Lyman Alpha Reference Sample. VIII. Characterizing Lyman-Alpha Scattering in Nearby Galaxies

, 2017
32 pages, 51 figures, accepted to ...
Bridge, Joanna S., Hayes, Matthew, Melinder, Jens, Östlin, Göran, Gronwall, Caryl, Ciardullo, Robin, Atek, Hakim, Cannon, John M., Gronke, Max, Guaita, Lucia, Hagen, Alex, Herenz, Edmund Christian, Kunth, Daniel, Laursen, Peter, Mas-Hesse, J. Miguel, Pardy, Stephen A.   +15 more
openaire   +2 more sources

Chemodynamics of Lyman alpha emitters, Lyman break galaxies and elliptical galaxies [PDF]

EAS Publications Series, 2007
We report an ultra-high-resolution simulation that follows evolution from the earliest stages of galaxy formation through the period of dynamical relaxation. The bubble structures of gas revealed in our simulation ($< 3\times 10^8$ years) resemble closely the high-redshift Lyman $α$ emitters (LAEs).
Mori, Masao, Umemura, Masayuki
openaire   +2 more sources

The Magellan M2FS Spectroscopic Survey of High-redshift Galaxies: The Brightest Lyman-break Galaxies at z ∼ 6

The Astrophysical Journal
We present a study of a sample of 45 spectroscopically confirmed, UV luminous galaxies at z ∼ 6. They were selected as bright Lyman-break galaxies (LBGs) using deep multiband optical images in more than 2 deg ^2 of the sky, and subsequently identified ...
Shuqi Fu, Linhua Jiang, Yuanhang Ning, Weiyang Liu, Zhiwei Pan   +4 more
doaj   +1 more source

Two Micron‐Size Dark Dimensions

Fortschritte der Physik, Volume 73, Issue 8, August 2025.
Abstract Two extra dimensions of micron scale might simultaneously address the gauge and cosmological hierarchy problems. In this paper various observational bounds in scenarios with one and two large extra dimensions are examined, to see if they are compatible with the micron scale.
Luis A. Anchordoqui, Ignatios Antoniadis, Dieter Lüst   +2 more
wiley   +1 more source