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While numerical simulations suggest that the strength of the Lyman alpha (Lya) line of star-forming disk galaxies strongly depends on the inclination at which they are observed (i.e. from edge-on to face-on, we expect to see a change from…

Recent work has shown that UV-luminous reionization-era galaxies often exhibit strong Lyman-alpha emission despite being situated at redshifts where the IGM is thought to be substantially neutral. It has been argued that this enhanced…

During the epoch of reionisation the first galaxies were enshrouded in pristine neutral gas, with one of the brightest emission lines in star-forming galaxies, Lyman-$\alpha$ (Ly$\alpha$), expected to remain undetected until the Universe…

Far-ultraviolet (FUV) radiation plays an important role in determining chemical abundances in protoplanetary disks. HI Lyman alpha is suspected to be the dominant component of the FUV emission from Classical T Tauri Stars (CTTSs), but is…

Solar and Stellar Astrophysics · Physics 2021-09-06 Rebecca Schindhelm , Kevin France , Gregory Herczeg , Edwin Bergin , Hao Yang , Alexander Brown , Joanna Brown , Jeffrey Linsky , Jeff Valenti

We present new simulations of Lyman-$\alpha$ (Ly$\alpha$) intensity maps that include Ly$\alpha$ radiative transfer in the intergalactic medium (IGM) and all significant sources of Ly$\alpha$ photons. The sources considered include…

Astrophysics of Galaxies · Physics 2025-08-29 Abigail E. Ambrose , Eli Visbal , Mihir Kulkarni , Matthew McQuinn

We present the results of a search for Lyman-alpha emission galaxies at z~ 5.7 in the FORS Deep Field. The objective of this study is to improve the faint end of the luminosity function of high-redshift Lyman-alpha emitting galaxies and to…

Astrophysics · Physics 2009-11-11 C. Tapken , I. Appenzeller , A. Gabasch , J. Heidt , U. Hopp , R. Bender , D. Mehlert , S. Noll , S. Seitz , W. Seifert

We present simulations of Lyman-Alpha radiation transfer in an isolated disk galaxy with a turbulence sub-grid model, multi-phase interstellar medium and detailed star formation modelling. We investigate the influence of inclination on the…

Astrophysics of Galaxies · Physics 2018-06-20 Christoph Behrens , Harald Braun

The chromospheric Lyman-alpha line of neutral hydrogen (Ly$\alpha$; 1216 \r{A}) is the most intense emission line in the solar spectrum, yet until recently observations of flare-related Ly$\alpha$ emission have been scarce. Here, we examine…

Solar and Stellar Astrophysics · Physics 2023-07-25 Harry J. Greatorex , Ryan O. Milligan , Phillip C. Chamberlin

We developed a Monte Carlo code that describes the resonant Lyman alpha line transfer in an optically thick, dusty, and static medium. The code was tested against the analytic formula derived by Neufeld (1990). We explain the line transfer…

Astrophysics · Physics 2016-08-30 Sang-Hyeon Ahn , Hee-Won Lee , Hyung-Mok Lee

We compute the polarization of the Lyman alpha line photons emerging from an anisotropically expanding and optically thick medium, which is expected to operate in many Lyman alpha emitting objects including the primeval galaxy DLA~2233+131…

Astrophysics · Physics 2009-10-30 Hee-Won Lee , Sang-Hyeon Ahn

The intergalactic medium (IGM) prior to the epoch of reionization consists mostly of neutral hydrogen gas. Ly-alpha photons produced by early stars resonantly scatter off hydrogen atoms, causing energy exchange between the radiation field…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Antonija Oklopcic , Christopher M. Hirata

The estimate of the ionizing UV background through the proximity effect analysis is discussed. Taking into account the correct bending of the column density distribution which appears in high resolution high s/n data, a value of the UV…

Astrophysics · Physics 2007-05-23 E. Giallongo , S. Cristiani , S. D'Odorico , A. Fontana , S. Savaglio

The spectra of the first galaxies and quasars in the Universe should be strongly absorbed shortward of their rest-frame Lyman-alpha wavelength by neutral hydrogen (HI) in the intervening intergalactic medium. However, the Lyman-alpha line…

Astrophysics · Physics 2009-09-28 Abraham Loeb , George Rybicki

The intrinsic strength of the Ly$\alpha$ line in young, star-forming systems makes it a special tool for studying high-redshift galaxies. However, interpreting observations remains challenging due to the complex radiative transfer involved.…

Astrophysics of Galaxies · Physics 2019-06-05 Christoph Behrens , Andrea Pallottini , Andrea Ferrara , Simona Gallerani , Livia Vallini

The Lyman $\alpha$ (Ly$\alpha$) line from high-redshift galaxies is a powerful probe of the Epoch of Reionization (EoR). Neutral hydrogen in the intergalactic medium (IGM) can significantly attenuate the emergent Ly$\alpha$ line, even in…

Astrophysics of Galaxies · Physics 2026-02-17 Samuel Gagnon-Hartman , Andrei Mesinger , Ivan Nikolić , Eleonora Parlanti , Giacomo Venturi

We present reduced and calibrated high resolution Lyman-alpha (Lya) images for a sample of 6 local star forming galaxies. Targets were selected to represent a range in luminosity and metallicity and to include both known Lya emitters and…

We use a new method to model fluctuations of the Lyman-Werner (LW) and Lyman-alpha radiation backgrounds at high redshift. At these early epochs the backgrounds are symptoms of a universe newly lit with its first stars. LW photons…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Lauren N. Holzbauer , Steven R. Furlanetto

We use very large cosmological Smoothed-Particle-Hydrodynamics simulations to study the properties of high redshift Lyman-alpha emitters (LAEs). We identify star-forming galaxies at z=3.1 in a cosmological volume of 100 h^-1Mpc on a side.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Ikkoh Shimizu , Naoki Yoshida , Takashi Okamoto

Using a spectral stacking technique we searched for the average \lya emission from high-z Damped \lya (DLA) galaxies detected in the Sloan Digital Sky Survey QSO spectra. We used a sample of 341 DLAs of mean redshift <z>= 2.86 and log N(HI)…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 H. Rahmani , R. Srianand , P. Noterdaeme , P. Petitjean

We review the spectral properties of the population of star forming galaxies at z = 3 discovered using a colour selection technique which targets the Lyman discontinuity at 912 Angstroms. The UV luminosity of the typical z = 3 galaxy…

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