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Related papers: Lyman-$\alpha$ Escape through Anisotropic Media

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The Lyman alpha (LyA) line of neutral hydrogen plays a central role in observations of star-forming galaxies. However, resonant scattering makes it difficult to directly interpret LyA signatures. Monte Carlo radiative transfer (MCRT)…

Astrophysics of Galaxies · Physics 2025-12-11 Kevin Lorinc , Aaron Smith , Olof Nebrin , Joshua Kasiri

We have studied the effects of gas density inhomogeneities on the escape of ionising Lyman continuum (Lyc) photons from Milky Way-type galaxies via 3D numerical simulations using the Monte Carlo radiative transfer code CRASH (Ciardi et al.…

Astrophysics · Physics 2009-11-07 B. Ciardi , S. Bianchi , A. Ferrara

We investigate the relationship between the Lyman-alpha (Lya) forest transmission in the intergalactic medium (IGM) and the environmental density of galaxies, focusing on its implications for the measurement of ionizing radiation escape…

Astrophysics of Galaxies · Physics 2025-04-24 C. Scarlata , W. Hu , M. J. Hayes , S. Taamoli , A. A. Khostovan , C. M. Casey , A. L. Faisst , J. S. Kartaltepe , Y. Lin , M. Salvato , M. Rafelski

Lyman-alpha (Lya) photons that escape the interstellar medium of star-forming galaxies may be resonantly scattered by neutral hydrogen atoms in the circumgalactic and intergalactic media, thereby increasing the angular extent of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Zheng Zheng , Renyue Cen , David Weinberg , Hy Trac , Jordi Miralda-Escude

Lyman-$\alpha$ (Ly$\alpha$) is the most prominent ultraviolet emission line in low-mass stars, playing a crucial role in exoplanet atmospheric photochemistry, heating, and escape. However, interstellar medium (ISM) absorption typically…

The hydrogen Lyman-alpha (Lya) emission line, the brightest spectral feature of a photoionized gas, is considered an indirect tracer of the escape of Lyman continuum (LyC) photons, particularly when the intergalactic medium is too opaque…

The Lya line transfer in an extremely thick medium of neutral hydrogen is investigated by adopting an accelerating scheme in our Monte Carlo code to skip a large number of core or resonant scatterings. This scheme reduces computing time…

Astrophysics · Physics 2009-11-07 Sang-Hyeon Ahn , Hee-Won Lee , Hyung Mok Lee

We combine a cosmological reionization simulation with box size of 100Mpc/h on a side and a Monte Carlo Lyman-alpha (Lya) radiative transfer code to model Lyman Alpha Emitters (LAEs) at z~5.7. The model introduces Lya radiative transfer as…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Zheng Zheng , Renyue Cen , Hy Trac , Jordi Miralda-Escude

(Abridged) Lyman-alpha (Lya) is a dominant probe of the galaxy population at high-z. However, interpretation of data drawn from Lya alone hinges on the Lya escape fraction which, due to the complex radiative transport, may vary greatly.…

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

We suggest that low optical depth in the Lyman continuum (LyC) may relate the Ly-alpha emission, C II and Si II absorption, and C II* and Si II* emission seen in high-redshift galaxies. We base this analysis on Hubble Space Telescope COS…

Astrophysics of Galaxies · Physics 2015-06-22 A. E. Jaskot , M. S. Oey

We perform Lyman-$\alpha$ (Ly$\alpha$) Monte-Carlo radiative transfer calculations on a suite of $2500$ models of multiphase, outflowing media, which are characterized by $14$ parameters. We focus on the Ly$\alpha$ spectra emerging from…

Astrophysics of Galaxies · Physics 2016-07-20 Max Gronke , Mark Dijkstra

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

We report Hubble Space Telescope/Cosmic Origins Spectrograph observations of the Ly$\alpha$ emission and interstellar absorption lines in a sample of ten star-forming galaxies at $z\sim0.2$. Selected on the basis of high equivalent width…

Astrophysics of Galaxies · Physics 2015-08-19 Alaina Henry , Claudia Scarlata , Crystal L. Martin , Dawn Erb

Lyman-$\alpha$ photons enable the cosmic dawn 21-cm signal through a process called the Wouthuysen-Field effect. An accurate model of the signal in this epoch hinges on the accuracy of the computation of the Ly$\alpha$ coupling, which…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-18 Shikhar Mittal , Girish Kulkarni , Thibault Garel

We investigate the Lyman alpha line transfer in nearby and high redshift starbursting galaxies, where the effect of high optical depths and the role of dust in the scattering medium are expected to be conspicuous and should be treated in a…

Astrophysics · Physics 2009-10-31 Sang-Hyeon Ahn , Hee-Won Lee , Hyung Mok Lee

The vast majority of star-forming galaxies are surrounded by large reservoirs of gas ejected from the interstellar medium. Ultraviolet absorption and emission lines represent powerful diagnostics to constrain the cool phase of these…

One of the current challenges in galaxy evolution studies is to establish the mechanisms that govern the escape of ionizing radiation from galaxies. Here, we investigate the connection between Lyman Continuum (LyC) escape and the conditions…

The escape of Lyman continuum (LyC) radiation from early galaxies transformed the intergalactic medium (IGM) and is intimately connected to the fueling and feedback processes that regulate galaxy evolution. IGM attenuation interferes with…

Astrophysics of Galaxies · Physics 2025-08-27 Anne E. Jaskot

The Lyman alpha emission line is an essential diagnostic tool for probing galaxy formation and evolution. Not only is it commonly the strongest observable line from high-redshift galaxies but from its shape detailed information about its…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Peter Laursen , Jesper Sommer-Larsen , Anja C. Andersen