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Related papers: Ly-alpha Radiative Transfer: A Stokes Vector Appro…

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We investigate the escape of Ly$\beta$ from emission nebulae with a significant population of excited hydrogen atoms in the level $n=2$, rendering them optically thick in H$\alpha$. The transfer of Ly$\beta$ line photons in these optically…

High Energy Astrophysical Phenomena · Physics 2018-03-21 Seok-Jun Chang , Hee-Won Lee , Sang-Hyeon Ahn , Hogyu Lee , Rodolfo Angeloni , Tali Palma , Francesco Di Mille

We propose to infer ionising continuum leaking properties of galaxies by looking at their Lyman-alpha line profiles. We carry out Lyman-alpha radiation transfer calculations in two models of HII regions which are porous to ionising…

Astrophysics of Galaxies · Physics 2015-05-27 A. Verhamme , I. Orlitova , D. Schaerer , M. Hayes

During the epoch of reionization the 21cm signal is sensitive to the scattering rate of the ultraviolet photons, redshifting across the Lyman_alpha resonance. Here we calculate the photon scattering rate profile for a single ultraviolet…

Astrophysics · Physics 2009-11-13 Leonid Chuzhoy , Zheng Zheng

Lyman alpha blobs (LABs) are spatially extended lyman alpha nebulae seen at high redshift. The origin of Lyman alpha emission in the LABs is still unclear and under debate. To study their heating mechanism(s), we present Australia Telescope…

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 present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of eight compact star-forming galaxies at redshifts z=0.02811-0.06540, with low oxygen abundances 12+log(O/H)=7.43-7.82 and extremely high…

Astrophysics of Galaxies · Physics 2019-11-27 Y. I. Izotov , D. Schaerer , G. Worseck , A. Verhamme , N. G. Guseva , T. X. Thuan , I. Orlitova , K. J. Fricke

Lyman-$\alpha$ blobs (LABs) are spatially extended nebulae of emission in the Ly$\alpha$ line of hydrogen, seen at high redshifts$^{1,2}$, and most commonly found in the dense environment of star-forming galaxies$^{3,4}$. The origin of…

We report the detection of diffuse Ly$\alpha$ emission, or Ly$\alpha$ halos (LAHs), around star-forming galaxies at $z\approx3.78$ and $2.66$ in the NOAO Deep Wide-Field Survey Bo\"otes field. Our samples consist of a total of $\sim$1400…

Lyman-$\alpha$ (Ly$\alpha$) is the strongest emission line in the accretion-generated UV spectra from T-Tauri stars and, as such, plays a critical role in regulating chemistry within the surrounding protoplanetary disks. Due to its resonant…

Solar and Stellar Astrophysics · Physics 2024-02-20 Seok-Jun Chang , Nicole Arulanantham , Max Gronke , Gregory J. Herczeg , Edwin A. Bergin

Evolved late-type stars are frequently identified as photometric and spectroscopic variables, such as Mira-type or semi-regular variable objects. These stars can also be polarimetrically variable, an indicator of non-spherical geometry for…

Solar and Stellar Astrophysics · Physics 2025-12-04 R Ignace , C Erba , K DeGennaro , G Henson

Bow shocks and related density enhancements produced by the winds of massive stars moving through the interstellar medium provide important information regarding the motions of the stars, the properties of their stellar winds, and the…

Solar and Stellar Astrophysics · Physics 2018-04-04 Manisha Shrestha , Hilding R. Neilson , Jennifer L. Hoffman , Richard Ignace

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 present two uniformly observed spectroscopic samples of Ly-alpha emitters (LAEs) (127 at z = 5.7 and 82 at z = 6.6), which we use to investigate the evolution of the LAE population at these redshifts. The observations cover a large field…

Astrophysics of Galaxies · Physics 2024-07-15 A. Songaila , L. L. Cowie , A. J. Barger , E. M. Hu , A. J. Taylor

Probing the magnetism of the upper solar chromosphere requires measuring and modeling the scattering polarization produced by anisotropic radiation pumping in UV spectral lines. Here we apply PORTA (a novel radiative transfer code) to…

Solar and Stellar Astrophysics · Physics 2015-06-23 Jiri Stepan , Javier Trujillo Bueno , Jorrit Leenaarts , Mats Carlsson

High-redshift Lyman-alpha blobs (LABs) are an enigmatic class of objects that have been the subject of numerous observational and theoretical investigations. It is of particular interest to determine the dominant power sources for the…

The extended Ly$\alpha$ haloes (LAHs) have been found to be prevalent around high-redshift star-forming galaxies. However, the origin of the LAHs is still a subject of debate. Spatially resolved analysis of Ly$\alpha$ profiles provides an…

Lyman alpha halos are observed ubiquitously around star-forming galaxies at high redshift, but their origin is still a matter of debate. We demonstrate that the emission from faint unresolved satellite sources, $M_{\rm UV} \gtrsim -17$,…

Astrophysics of Galaxies · Physics 2017-05-31 Lluís Mas-Ribas , Mark Dijkstra , Joseph F. Hennawi , Michele Trenti , Rieko Momose , Masami Ouchi

The STOKES Monte Carlo radiative transfer code has been extended to model the velocity dependence of the polarization of emission lines. We use STOKES to present improved modelling of the velocity-dependent polarization of broad emission…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Rene W. Goosmann , C. Martin Gaskell , Frederic Marin

We examine the dust geometry and Ly{\alpha} scattering in the galaxies of the Lyman Alpha Reference Sample (LARS), a set of 14 nearby (0.02 < $z$ < 0.2) Ly{\alpha} emitting and starbursting systems with Hubble Space Telescope Ly{\alpha},…

The Lyman-alpha reference sample (LARS) is a program with the Hubble Space Telescope (HST) that provides a sample of local universe laboratory galaxies in which to study the astrophysics of the visibility and strength of the Lyman-alpha…