Results 61 to 70 of about 5,863 (203)

The Galaxy Proximity Effect in the Lyman-alpha Forest

, 2002
Hydrodynamic cosmological simulations predict that the average opacity of the Ly-alpha forest should increase in the neighborhood of galaxies because galaxies form in dense environments. Recent observations (Adelberger et al. 2002) confirm this expectation at large scales, but they show a decrease of absorption at comoving separations Delta_r ~ 1 Mpc/h
Kollmeier, Juna A., Weinberg, David H., Dave', Romeel, Katz, Neal   +3 more
openaire   +2 more sources

Ionospheric D Region: Characteristics Near Dawn and Dusk

Journal of Geophysical Research: Space Physics, Volume 130, Issue 4, April 2025.
Abstract The characteristics of very low frequency (VLF) radio wave propagation in the Earth‐ionosphere waveguide are determined particularly through dawn and dusk using phase and amplitude measurements of man‐made signals propagating below the ionospheric D region. For the first time variations of “Wait” height and sharpness parameters, H' and β, have
Neil R. Thomson, Mark A. Clilverd, Craig J. Rodger   +2 more
wiley   +1 more source

MIDIS: JWST NIRCam and MIRI Unveil the Stellar Population Properties of Lyα Emitters and Lyman-break Galaxies at z ≃ 3–7

The Astrophysical Journal
We study the stellar population properties of 182 spectroscopically confirmed (MUSE/VLT) Ly α emitters (LAEs) and 450 photometrically selected Lyman-break galaxies (LBGs) at z = 2.8–6.7 in the Hubble Extreme Deep Field.
Edoardo Iani, Karina I. Caputi, Pierluigi Rinaldi, Marianna Annunziatella, Leindert A. Boogaard, Göran Östlin, Luca Costantin, Steven Gillman, Pablo G. Pérez-González, Luis Colina, Thomas R. Greve, Gillian Wright, Almudena Alonso-Herrero, Javier Álvarez-Márquez, Arjan Bik, Sarah E. I. Bosman, Alejandro Crespo Gómez, Andreas Eckart, Jens Hjorth, Iris Jermann, Alvaro Labiano, Danial Langeroodi, Jens Melinder, Thibaud Moutard, Florian Peißker, John P. Pye, Tuomo V. Tikkanen, Paul P. van der Werf, Fabian Walter, Thomas K. Henning, Pierre-Olivier Lagage, Ewine F. van Dishoeck   +31 more
doaj   +1 more source

A GLIMPSE into the very faint end of the Hβ+[O III]λλ4960,5008 luminosity function at z ∼ 7 – 9 behind Abell S1063

Astronomy & Astrophysics
We used the ultra-deep GLIMPSE JWST/NIRCam survey to constrain the faint end of the [O III]+Hβ luminosity function (LF) down to 1039erg s−1 at z ∼ 7 − 9 behind the lensed Hubble Frontier Field galaxy cluster Abell S1063.
Korber Damien, Chemerynska Iryna, Furtak Lukas J., Atek Hakim, Endsley Ryan, Schaerer Daniel, Chisholm John, Kokorev Vasily, Saldana-Lopez Alberto, Adamo Angela, Muñoz Julian B., Oesch Pascal A., Meyer Romain, Marques-Chaves Rui, Fujimoto Seiji   +14 more
doaj   +1 more source

Correlation Between the Delay and Rise Time of VLF/LF Amplitudes During 20 Solar X‐Ray Flares Observed in February 2014 at Mid‐Latitude

Radio Science, Volume 60, Issue 4, April 2025.
Abstract During daylight hours, the concentration of electrons in the ionosphere can be amplified by solar flares, which may subsequently influence the propagation of radio waves. Previous research on Very Low Frequency (VLF) signals focused on X‐class and M‐class flares.
Y. Liu, M. Füllekrug
wiley   +1 more source

Predicting Lyman-continuum emission of galaxies using their physical and Lyman-alpha emission properties

, 2023
Aims. The primary difficulty in understanding the sources and processes that powered cosmic reionization is that it is not possible to directly probe the ionizing Lyman-continuum (LyC) radiation at that epoch as those photons have been absorbed by the ...

core   +1 more source

Lyman-alpha absorbers arising in galaxy clusters

, 1997
2 pages, 2 figures, to appear in the proceedings of the 13th IAP Conference on "Evolution of the Intergalactic Medium From QSO Absorption Line Systems"
Ortiz-Gil, A., Lanzetta, K. M., Webb, J. K., Barcons, X.   +3 more
openaire   +2 more sources

Impact of Sudden Stratospheric Warming and Elevated Stratopause Events on the Very Low Frequency Radio Signal

Journal of Geophysical Research: Space Physics, Volume 130, Issue 3, March 2025.
Abstract Sudden Stratospheric Warmings (SSW) and Elevated Stratopause (ES) events are mid‐to‐high latitudinal, atmospheric wave‐driven phenomena leading to significant changes in wind, temperatures, and vertical mass transport, especially at stratospheric and mesospheric altitudes.
H. Schneider, V. Wendt, D. Banyś, M. Hansen, M. Clilverd, P. T. Verronen   +5 more
wiley   +1 more source

The Impact of Cosmic Variance on Inferences of Global Neutral Fraction Derived from Lyα Luminosity Functions during Reionization

The Astrophysical Journal, 2023
We investigate the impact of field-to-field variation, deriving from cosmic variance, in measured Ly α emitter (LAE) luminosity functions (LFs) and this variation’s impact on inferences of the neutral fraction of the intergalactic medium (IGM) during ...
Sean Bruton, Claudia Scarlata, Francesco Haardt, Matthew J. Hayes, Charlotte Mason, Alexa M. Morales, Andrei Mesinger   +6 more
doaj   +1 more source

Das zirkumgalaktische Medium

Physik in unserer Zeit, Volume 56, Issue 1, Page 30-37, January 2025.
Galaxien wie die Milchstraße sind umhüllt von einem gigantischen Kokon aus diffusem Gas. Aktuelle Forschungsergebnisse belegen, dass dieses zirkumgalakische Medium eine entscheidende Rolle für die Entstehung und Entwicklung von Galaxien spielt. Zusammenfassung Als zirkumgalaktisches Medium bezeichnet man die gasförmigen Hüllen von Galaxien, die sich ...
Philipp Richter
wiley   +1 more source