Related papers: Lyman-alpha Absorption from Heliosheath Neutrals
We use self-consistent kinetic/hydrodynamic models of the heliosphere to predict H I Lyman-alpha absorption profiles for various lines of sight through the heliosphere. These results are compared with Lyman-alpha absorption lines of six…
We search the Hubble Space Telescope (HST) archive for previously unanalyzed observations of stellar H I Lyman-alpha emission lines, our primary purpose being to look for new detections of Lyman-alpha absorption from the outer heliosphere,…
We use newly developed 3D kinetic MHD models of the heliosphere to predict heliospheric H I Lyman-alpha absorption for various lines of sight. These predictions are compared with actual Lyman-alpha spectra from the Hubble Space Telescope,…
In this paper, we study heliospheric Ly-$\alpha$ absorption toward nearby stars in different lines of sight. We use the Baranov-Malama model of the solar wind interaction with a two-component (charged component and H atoms) interstellar…
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 =…
We use an updated self-consistent kinetic/gasdynamic model of the solar wind/interstellar flow interaction to compute the Lyman-alpha absorption by hydrogen atoms of both interstellar and solar origin generated in the heliospheric…
We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption lines in the outer regions of eight nearby galaxies using background QSOs and AGN as probes. Lya lines are detected within a few hundred km/s of the systemic velocity…
The Ly$\alpha$ emission line is one of the main observables of galaxies at high redshift, but its output depends strongly on the neutral gas distribution and kinematics around the star-forming regions where UV photons are produced. We…
We present results from a spectroscopic and imaging survey of galaxies in the fields of quasars from the HST Quasar Absorption Line Key Project. The aim of this survey is to identify galaxies within 3.5' from the quasar sightline, to a…
To shed more light on the nature of the observed Ly{\alpha} absorption during transits of HD 209458b and to quantify the major mechanisms responsible for the production of fast hydrogen atoms (the so called energetic neutral atoms, ENAs)…
We present an investigation of the properties of the extended Ly$\alpha$ halo and the large-scale \ion{H}{I} absorbing structures associated with 5 high-redshift radio galaxies at z $>$ 2, using the Goodman long-slit spectrograph on the…
We present high dispersion HST GHRS UV spectroscopic observations of 8 HII galaxies covering a wide range of metallicities and physical properties. We have found Lyalpha emission in 4 galaxies with blueshifted absorption features, leading…
Using STIS - HST observations, we have detected an extended upper atmosphere in the extrasolar planet HD209458b . The spectra show an absorption of (15+/-4)% of the stellar Ly-alpha emission line during the planetary transit in front of the…
We have used STIS aboard HST to search for Lyman-alpha (Lya) absorption in the outer regions of nine nearby (cz<6000 km/s) galaxies using background QSOs and AGN as probes. The foreground galaxies are intercepted between 26 and 199 h-1 kpc…
We present an analysis of the evolution of the Ly alpha absorption lines in the redshift interval 0.0 to \sim 1.5 based upon a sample of 987 lines identified in the spectra of 63 QSOs obtained with the Faint Object Spectrograph on the…
The importance of HST for the study of quasar absorption lines and of the nature of the intergalactic medium is illustrated by reviewing selected results from past HST observations. Topics reviewed include the study of Ly-alpha absorbers at…
The Lyman alpha absorption from intergalactic, once-ionized helium (HeII) has been measured with HST in four quasars over the last few years, over the redshift range 2.4 < z < 3.2. These observations have indicated that the HeII…
We present a reanalysis of the HeII Lyman alpha absorption towards the quasars HS1700+6416 and HE2347-4342 using new high S/N, optical observations. An alternative analysis method is applied, which fits the high quality, optical HI data…
During September 2023 the Alice ultraviolet spectrograph on the New Horizons (NH) spacecraft was used to map diffuse Lyman alpha (Lya) emission over most of the sky, at a range of 56.9 AU from the Sun. At that distance, models predict that…
We measure the amount of absorption in the Lyman-alpha forest at 0 < z < 1.6 in HST FOS spectra of 74 QSOs. At 0 < z < 1.6 we find that 79% of the absorption is from the low density intergalactic medium, 12% from metals and 9% from the…