An attempt to determine stellar Lyman-alpha emission-line fluxes for F stars with different metal abundances

1983 ◽  
Vol 265 ◽  
pp. 331 ◽  
Author(s):  
E. Bohm-Vitense ◽  
J. Woods
Keyword(s):  
Emission Line ◽  
Lyman Alpha ◽  
Alpha Emission ◽  
Metal Abundances ◽  
F Stars

scholarly journals Lyman Edges in Quasar Spectra

1989 ◽  
Vol 134 ◽  
pp. 555-556
Author(s):  
A. L. Kinney ◽  
R.R.J. Antonucci ◽  
H. C. Ford
Keyword(s):  
High Resolution ◽  
Emission Line ◽  
High Redshift ◽  
Edge Region ◽  
Disk Model ◽  
High Resolution Data ◽  
Lyman Alpha ◽  
Alpha Emission ◽  
Quasar Spectra ◽  
Resolution Data

This is a study of the Lyman edge region in the spectra of eleven high redshift quasars. We present large aperture, low resolution data designed to detect broadened Lyman edge absorption predicted by thermal models of the Big Blue Bump continuum component. We also present high resolution data on the edge regions and the Lyman alpha emission line for nine of the objects. We show some partial absorption edges and discuss whether or not they can be interpreted as support for the accretion disk model.

scholarly journals Lyman Alpha Emitting Galaxies in the Nearby Universe

2015 ◽  
Vol 32 ◽  
Author(s):  
Matthew Hayes
Keyword(s):  
Interstellar Medium ◽  
Large Scale ◽  
Neutral Hydrogen ◽  
Emission Feature ◽  
Ultraviolet Continuum ◽  
Lyman Alpha ◽  
Alpha Emission ◽  
Multi Wavelength ◽  
Metal Abundances ◽  
Galaxy Population

AbstractThe Lyman alpha emission line (Lyα) of neutral hydrogen (Hi) is intrinsically the brightest emission feature in the spectrum of astrophysical nebulae, making it a very attractive observational feature with which to survey galaxies. Moreover as an ultraviolet resonance line, Lyα possesses several unique characteristics that make it useful to study the properties of the interstellar medium and ionising stellar population at all cosmic epochs. In this review, I present a summary of Lyα observations of galaxies in the nearby universe. By ultraviolet continuum selection, at the magnitudes reachable with current facilities, only ≈ 5% of the local galaxy population shows a Lyα equivalent width (WLyα) that exceeds 20 Å. This fraction increases dramatically at higher redshifts, but only in the local universe can we study galaxies in detail and assemble unprecedented multi-wavelength datasets. I discuss many local Lyα observations, showing that when galaxies show net Lyα emission, they ubiquitously also produce large-scale halos of scattered Lyα, that dominate the integrated luminosity. Concerning global measurements, we discuss how WLyα and the Lyα escape fraction (fLyαesc) are higher (WLyα ≳ 20 Å and fLyαesc ≳ 10%) in galaxies that represent the less massive and younger end of the distribution for local objects. This is connected with various properties, such that Lyα-emitting galaxies have lower metal abundances (median value of 12 + log(O/H) ~ 8.1) and dust reddening. However, the presence of galactic outflows/winds is also vital to Doppler shift the Lyα line out of resonance with the atomic gas, and high WLyα is found only among galaxies with winds faster than ~ 50 km s−1. The empirical evidence is then assembled into a coherent picture, and the requirement for star-formation-driven feedback is discussed in the context of an evolutionary sequence where the interstellar medium is accelerated and/or subject to hydrodynamical instabilities, which reduce the scattering of Lyα. Concluding remarks take the form of perspectives upon future developments, and the most pressing questions that can be answered by observation.

The Solar Lyman-Alpha Emission Line.

1961 ◽  
Vol 133 ◽  
pp. 596 ◽  
Author(s):  
Donald C. Morton ◽  
Kenneth G. Widing
Keyword(s):  
Emission Line ◽  
Lyman Alpha ◽  
Alpha Emission

scholarly journals Tracking the Lyman alpha emission line in the CircumGalactic Medium in MUSE data

2016 ◽  
Vol 78-79 ◽  
pp. 233-245
Author(s):  
R. Bacher ◽  
P. Maho ◽  
F. Chatelain ◽  
O. Michel
Keyword(s):  
Emission Line ◽  
Lyman Alpha ◽  
Alpha Emission ◽  
Circumgalactic Medium

Ionized gas kinematics and luminosity profiles of Low-z Lyman Alpha Blobs

2019 ◽  
Vol 15 (S359) ◽  
pp. 413-414
Author(s):  
María P. Agüero ◽  
Rubén Díaz ◽  
Mischa Schirmer
Keyword(s):  
Emission Line ◽  
Galactic Nuclei ◽  
Host Galaxies ◽  
Ionized Gas ◽  
Lyman Alpha ◽  
Gas Kinematics ◽  
The Universe ◽  
Very High ◽  
The Continuum

AbstractThis work is focused on the characterization of the Seyfert-2 galaxies hosting very large, ultra-luminous narrow-line regions (NLRs) at redshifts z = 0.2−0.34. With a space density of 4.4 Gcp−3 at z ∼ 0.3, these “Low Redshift Lyman-α Blob” (LAB) host galaxies are amongst the rarest objects in the universe, and represent an exceptional and short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). We present the study of GMOS spectra for 13 LAB galaxies covering the rest frame spectral range 3700–6700 Å. Predominantly, the [OIII]λ5007 emission line radial distribution is as widespread as that of the continuum one. The emission line profiles exhibit FWHM between 300–700 Km s−1. In 7 of 13 cases a broad kinematical component is detected with FWHM within the range 600–1100 Km s−1. The exceptionally high [OIII]λ5007 luminosity is responsible for very high equivalent width reaching 1500 Å at the nucleus.

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