Related papers: Using Lyman-$\alpha$ transits to constrain models …
We study the properties of Ly-alpha emitters in a cosmological framework by computing the escape of Ly-alpha photons through galactic outflows. We combine the GALFORM semi-analytical model of galaxy formation with a Monte Carlo Ly-alpha…
The presence of broad wings in the H$\alpha$ line is commonly used as a diagnostic of the presence and properties of galactic winds from star-forming galaxies. However, the accuracy of this approach has not been subjected to extensive…
Ly$\alpha$ emission is possibly the best indirect diagnostic of Lyman continuum (LyC) escape since the conditions that favor the escape of Ly$\alpha$ photons are often the same that allows for the escape of LyC photons. In this work, we…
(Abridged) The upper atmospheres of close-in gas giant exoplanets are subjected to intense heating/tidal forces from their parent stars. Atomic/ionized hydrogen (H) layers are sufficiently rarefied that magnetic pressure may dominate gas…
We develop a flexible one-dimensional code to model the escape of hydrogen and helium from a hot Jupiter as a result of photoionization from extreme-ultraviolet (EUV) radiation. We include stellar spectrum heating and ionization, radiative…
We review recent developments in the theory of the Lyman-alpha forest and their implications for the role of the forest as a test of cosmological models. Simulations predict a relatively tight correlation between the local Lya optical depth…
Galactic outflows produced by stellar feedback are known to be multiphase in nature. Both observations and simulations indicate that the material within several kpc of galactic disk mid-planes consists of warm clouds embedded within a hot…
To date, more than 750 planets have been discovered orbiting stars other than the Sun. Two sub-classes of these exoplanets, "hot Jupiters" and their less massive counterparts "hot Neptunes," provide a unique opportunity to study the…
Hydrogen Ly-alpha is our primary emission-line window into high redshift galaxies. Surprisingly, despite an extensive literature, Ly-alpha radiative transfer in the most realistic case of a dusty, multi-phase medium has not received…
The detections of atomic hydrogen, heavy atoms and ions surrounding the extrasolar giant planet (EGP) HD209458b constrain the composition, temperature and density profiles in its upper atmosphere. Thus the observations provide guidance for…
In recent years, a number of observations have been made of the transits of 'Hot Jupiters', such as HD 189733b, which have been modelled to derive atmospheric structure and composition. As measurement techniques improve, the transit spectra…
We use a general circulation model to study the three-dimensional (3-D) flow and temperature distributions of atmospheres on tidally synchronized extrasolar planets. In this work, we focus on the sensitivity of the evolution to the initial…
The role of radiation pressure in shaping exoplanet photoevaporation remains a topic of contention. Radiation pressure from the exoplanet's host star has been proposed as a mechanism to drive the escaping atmosphere into a "cometary" tail…
We test a method to reduce unwanted sample variance when predicting Lyman-$\alpha$ (ly$\alpha$) forest power spectra from cosmological hydrodynamical simulations. Sample variance arises due to sparse sampling of modes on large scales and…
The TRAPPIST-1 planetary system is observationally favorable for studying if planets orbiting M stars can retain atmospheres and host habitable conditions. Recent JWST secondary eclipse observations of TRAPPIST-1 c rule out a thick \ch{CO2}…
Ultra-hot Jupiters, an extreme class of planets not found in our solar system, provide a unique window into atmospheric processes. The extreme temperature contrasts between their day- and night-sides pose a fundamental climate puzzle: how…
Among the many recommendations of the Decadal Survey on Astronomy and Astrophysics 2020, we found that a priority area of research is to pave the pathways towards finding and characterizing habitable worlds. In this context, we aim to…
The inner edge of the classical habitable zone is often defined by the critical flux needed to trigger the runaway greenhouse instability. This 1D notion of a critical flux, however, may not be so relevant for inhomogeneously irradiated…
Cosmological probes pose an inverse problem where the measurement result is obtained through observations, and the objective is to infer values of model parameters which characterize the underlying physical system -- our Universe. Modern…
The M dwarf GJ 436 hosts a transiting warm Neptune known to experience atmospheric escape. Previous observations revealed the presence of a giant hydrogen exosphere transiting the star for more than 5 h, and absorbing up to 56% of the flux…