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The Lyman-alpha (Ly{\alpha};1216 {\AA}) line is the brightest emission line in the quiescent solar spectrum and radiates a significant fraction of the available nonthermal energy during flares. Despite its importance, there is a lack of…

太阳与恒星天体物理 · 物理学 2025-04-25 Luke Majury , Ryan Milligan , Elizabeth Butler , Harry Greatorex , Maria Kazachenko

The ultraviolet (UV) spectral energy distributions of low-mass (K- and M-type) stars play a critical role in the heating and chemistry of exoplanet atmospheres, but are not observationally well-constrained. Direct observations of the…

Lyman-{\alpha} emitters (LAEs) are a promising target to probe the large scale structure of the Universe at high redshifts, $z\gtrsim 2$. However, their detection is sensitive to radiative transfer effects that depend on local astrophysical…

宇宙学与河外天体物理 · 物理学 2019-04-10 Siddhartha Gurung-López , Álvaro A. Orsi , Silvia Bonoli , Carlton M. Baugh , Cedric G. Lacey

The hydrogen Lyman lines ( 91.2 nm < lambda < 121.6 nm) are significant contributors to the radiative losses of the solar chromosphere, and are enhanced during flares. We have shown previously that the Lyman lines observed by the Extreme…

太阳与恒星天体物理 · 物理学 2018-08-08 Stephen A Brown , Lyndsay Fletcher , Graham S Kerr , Nicolas Labrosse , Adam F Kowalski , Jaime De La Cruz Rodríguez

We present the first results from the X-SHOOTER Lyman-$\alpha$ survey at $z=2$ (XLS-$z2$). XLS-$z2$ is a deep spectroscopic survey of 35 Lyman-$\alpha$ emitters (LAEs) utilising $\approx90$ hours of exposure time with VLT/X-SHOOTER and…

Ly{\alpha} emission, Ly{\alpha} absorption and MgII absorption are powerful tracers of neutral hydrogen. Hydrogen is the most abundant element in the universe and plays a central role in galaxy formation via gas accretion and outflows, as…

星系天体物理 · 物理学 2015-06-22 Luke A. Barnes , Thibault Garel , Glenn G. Kacprzak

Utilizing {\it ab initio} ultra-high resolution hydrodynamical simulations, we investigate the properties of the interstellar and circum-galactic medium of Ly$\alpha$ Blobs (LABs) at $z=3$, focusing on three important emission lines:…

星系天体物理 · 物理学 2016-07-19 Samuel H. C. Cabot , Renyue Cen , Zheng Zheng

The Hydrogen Lyman-alpha (Lya) line shows a large variety of shapes which is caused by factors at different scales, from the interstellar medium to the intergalactic medium. This work aims to provide a systematic inventory and…

Ly$\alpha$ emission is widely used to detect and confirm high-redshift galaxies and characterize the evolution of the intergalactic medium. However, many galaxies do not display Ly$\alpha$ emission in typical spectroscopic observations, and…

星系天体物理 · 物理学 2020-01-08 Ryan F. Trainor , Allison L. Strom , Charles C. Steidel , Gwen C. Rudie , Yuguang Chen , Rachel L. Theios

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…

太阳与恒星天体物理 · 物理学 2023-07-25 Harry J. Greatorex , Ryan O. Milligan , Phillip C. Chamberlin

We have performed a multi-species hydrodynamical simulation of the formation and evolution of Lyman alpha clouds in a flat CDM dominated universe with an external flux of ionizing radiation. We solve the fully coupled non-equilibrium rate…

天体物理学 · 物理学 2009-10-28 Yu Zhang , Peter Anninos , Michael L. Norman

We present a new perturbative approach to "constrained Ly$\alpha$ radiative transfer'" (RT) through the circum- and inter-galactic medium (CGM and IGM). We constrain the HI content and kinematics of the CGM and IGM in a physically motivated…

星系天体物理 · 物理学 2018-08-22 Koki Kakiichi , Mark Dijkstra

Radiation pressure from Lyman-$\alpha$ (Ly$\alpha$) scattering is a potentially dominant form of early stellar feedback, capable of injecting up to $\sim 100 \, \times$ more momentum into the interstellar medium (ISM) than UV continuum…

星系天体物理 · 物理学 2025-01-10 Olof Nebrin , Aaron Smith , Kevin Lorinc , Johan Hörnquist , Åsa Larson , Garrelt Mellema , Sambit K. Giri

We demonstrate the redshift-evolution of the spectral profile of H i Lyman-alpha (Ly{\alpha}) emission from star-forming galaxies. In this first study we pay special attention to the contribution of blueshifted emission. At redshift z =…

星系天体物理 · 物理学 2021-02-18 Matthew J. Hayes , Axel Runnholm , Max Gronke , Claudia Scarlata

We present an exhaustive census of Lyman alpha (Ly$\alpha$) emission in the general galaxy population at $3<z<4.6$. We use the Michigan/Magellan Fiber System (M2FS) spectrograph to study a stellar mass (M$_*$) selected sample of 625…

星系天体物理 · 物理学 2017-07-17 Grecco A. Oyarzún , Guillermo A. Blanc , Valentino González , Mario Mateo , John I. Bailey

We present observations and results of radiance and irradiance studies completed by SoHO-SUMER during the past solar cycle. We find that the cycle variation in Ly-alpha irradiance as observed by e.g. UARS-SOLSTICE can not be explained by…

太阳与恒星天体物理 · 物理学 2010-02-19 W. Curdt , H. Tian

We extend a previous study of Lyman Alpha Emitters (LAEs) based on hydrodynamical cosmological simulations, by including two physical processes important for LAEs: (a) Lyman Alpha and continuum luminosities produced by cooling of…

宇宙学与河外天体物理 · 物理学 2015-05-13 Pratika Dayal , Andrea Ferrara , Alexandro Saro

Identifying the mechanisms driving the escape of Lyman Continuum (LyC) photons is crucial to find Lyman Continuum Emitter (LCE) candidates. To understand the physical properties involved in the leakage of LyC photons, we investigate the…

星系天体物理 · 物理学 2020-07-15 S. Gazagnes , J. Chisholm , D. Schaerer , A. Verhamme , Y. Izotov

Lyman-alpha is now widely used to investigate the galaxy formation and evolution in the high redshift universe. However, without a rigorous understanding of the processes which regulate the Lya escape fraction, physical interpretations of…

天体物理学 · 物理学 2008-09-15 Hakim Atek , Daniel Kunth , Matthew Hayes , Goeran Ostlin , J. Miguel Mas-Hesse , .

Ly-alpha emitting galaxies and giant Ly-alpha blobs (LABs) have been extensively observed to study the formation history of galaxies. However, the origin of their extended Ly-alpha emission, especially of LABs, remains controversial.…

星系天体物理 · 物理学 2022-02-23 Kwang-Il Seon , Hyunmi Song , Seok-Jun Chang