Related papers: Interplanetary Lyman $\alpha$ line profiles: varia…
We present new measurements of the flux power-spectrum P(k) of the $z<0.5$ HI Lyman-$\alpha$ forest spanning scales k ~ 0.001-0.1 s/km. These results were derived from 65 far ultraviolet quasar spectra (resolution R~18000) observed with the…
The clustering properties of Ly ${\alpha}$ lines are analysed using an intermediate resolution ($\sim 1\AA$) spectra of 67 QSOs compiled from the literature. The pair velocity correlation function indicates a weak excess in the velocity…
The determination of solar wind outflow velocity is fundamental in order to probe the mechanisms of wind acceleration in the corona. We aim to study, via the Doppler dimming technique, the effects that the chromospheric Ly{\alpha} line…
Lyman $\alpha$ observations of the transiting exoplanet HD 209458b enable the study of exoplanets exospheres exposed to stellar EUV fluxes, as well as the interacting stellar wind properties. In this study we present 3D hydrodynamical…
We constrain the H I photoionization rate $(\Gamma_{\rm HI})$ at $z \lesssim 0.45$ by comparing the flux probability distribution function and power spectrum of the Ly-$\alpha$ forest data along 82 QSO sightlines obtained using Cosmic…
Variations in the solar wind (SW) parameters with scales of several years are an important characteristic of solar activity and the basis for a long-term space weather forecast. We examine the behavior of interplanetary parameters over…
We present a quantitative model of Lyman-alpha (Ly-alpha) emission throughout cosmic history and determine the prospects for intensity mapping of spatial fluctuations in the Ly-alpha signal. Since i) our model assumes at z>6 the minimum…
Observation of the strengths and profiles of the hydrogen Balmer absorption series is an established technique for determining the effective temperature and surface gravity of hot H-rich white dwarf stars. In principle, the Lyman series…
We present high resolution spectroscopic observations of the massive X-ray binary system LS I+65 010=2S 0114+650 in the optical wavelength region. A correlation between equivalent width and radial velocity of photospheric absorption lines…
We investigate broad emission-line wings, reaching $\leq 800\rm~km~s^{-1}$, observed in 26 galaxies with Lyman continuum (LyC) observations, primarily from the Low-redshift Lyman Continuum Survey (LzLCS). Using Magellan/MIKE, VLT/X-shooter,…
The intensity of radiation at millimeter wavelengths from the solar atmosphere is closely related to the plasma temperature and the height of formation of the radiation is wavelength dependent. From that follows that the slope of the…
HST imaging and slitless spectroscopy are used to examine where the strong Lyman alpha emission escapes from the interstellar medium in the starburst galaxy Mkn 357. An H-alpha image shows that the ionized gas is mostly in a global wind,…
(Abridged) Despite the privileged position that Lyman-alpha (Lya) emission line holds in the exploration of the distant universe and modern observational cosmology, the origin of the observed diversity of lya profiles remains to be…
[Abridged] We present FLO (From Lines to Over-densities), a new technique to reconstruct the hydrogen density field for the Lya forest lines observed in high resolution QSO spectra. The method is based on the hypothesis that the Lya lines…
We present 40 fully hydrodynamical numerical simulations of the intergalactic gas that gives rise to the Ly-alpha forest. We make artificial spectra from each and measure three output parameters: the mean flux, a measure of the most common…
We improve our filament automated detection method which was proposed in our previous works. It is then applied to process the full disk H$\alpha$ data mainly obtained by Big Bear Solar Observatory (BBSO) from 1988 to 2013, spanning nearly…
In-situ observations of the solar wind (SW) plasma from 0.29 to 1AU show that the protons and alpha particles are often non-Maxwellian, with evidence of kinetic instabilities, temperature anisotropies, differential ion streaming, and…
The Extreme ultraviolet Variability Experiment was designed to observe the Sun-as-a-star in the extreme ultraviolet; a wavelength range that has remained spectrally unresolved for many years. It has provided a wealth of data on solar…
We perform Monte-Carlo radiative transfer calculations to model the Lyman alpha properties of galaxies in high-resolution, zoom-in cosmological simulations at z ~ 6.6. The simulations include both constrained and unconstrained runs,…
Analysis of interstellar absorption lines observed in high-resolution {\em HST} spectra of nearby stars provides temperatures, turbulent velocities, and kinetic properties of warm interstellar clouds. Previous studies identified 15 warm…