Related papers: Maser Flares Driven by Isothermal Shock Waves
We analyze a grid of radiative hydrodynamic simulations of solar flares to study the energy balance and response of the atmosphere to nonthermal electron beam heating. The appearance of chromospheric bubbles is one of the most notable…
Flaring activity in blazars can last for vastly different time-scales, and may be the result of density enhancements in the jet flow that result from the intrusion of an interstellar cloud into the jet. We investigate the lightcurves…
Methanol masers can provide valuable insight into the processes involved in high-mass star formation, however the local environment in which they form is still unclear. Four primary, yet conflicting, models have emerged to explain the…
Recent numerical simulations of the interstellar medium driven by energy input from supernovae and stellar winds indicate that HI clouds can be formed by compression in shock waves and colliding turbulent streams without any help from…
Our mid-infrared and near-infrared surveys over the last five years have helped to strengthen and clarify the relationships between water, methanol, and OH masers and the star formation process. Our surveys show that maser emission seems to…
The UV photon escape fraction from molecular clouds is a key parameter for understanding the ionization of the Interstellar Medium (ISM), and extragalactic processes, such as cosmic reionization. We present the ionizing photon flux and the…
We present simulations of initially stable isothermal clouds exposed to ionising radiation from a discrete external source, and identify the conditions that lead to radiatively driven implosion and star formation. We use the Smoothed…
Using a suite of radiation hydrodynamic simulations of star cluster formation in turbulent clouds, we study the escape fraction of ionizing (Lyman continuum) and non-ionizing (FUV) radiation for a wide range of cloud masses and sizes. The…
When two plasmas collide, their interaction can be mediated by collisionless plasma instabilities or binary collisions between particles of each shell. By comparing the maximum growth rate of the collisionless instabilities with the…
We investigate the triggering of star formation in clouds that form in Galactic scale flows as the ISM passes through spiral shocks. We use the Lagrangian nature of SPH simulations to trace how the star forming gas is gathered into…
The near infrared (1-2um) and the thermal infrared (3-25um) trace many of the environments in which masers are thought to reside, including shocks, outflows, accretion disks, and the dense medium near protostars. After a number of recent…
We derive and compare six theoretical models for the star formation rate (SFR) - the Krumholz & McKee (KM), Padoan & Nordlund (PN), and Hennebelle & Chabrier (HC) models, and three multi-freefall versions of these, suggested by HC - all…
We propose a new two-stage model for acceleration of electrons in solar flares. In the first stage, electrons are accelerated stochastically in a post-reconnection turbulent downflow. The second stage is the reprocessing of a subset of…
We set out the theory and discretization scheme for a new finite-element computer code, written specifically for the simulation of maser sources. The code was used to compute fractional inversions at each node of a 3-D domain for a range of…
The dynamics of the wind-wind collision in massive stellar binaries is investigated using three-dimensional hydrodynamical models which incorporate gravity, the driving of the winds, the orbital motion of the stars, and radiative cooling of…
Solar flares are often accompanied by filament/prominence eruptions, sometimes leading to coronal mass ejections (CMEs). By analogy, we expect that stellar flares are also associated with stellar CMEs whose properties are essential to know…
The properties of cosmic shock waves are studied through numerical simulations in two cosmological scenarios (SCDM and LCDM). The scaling relations for the average radius and velocity associated with the accretion shocks are somewhat…
Propagation of fast-mode magnetohydrodynamic (MHD) waves in the interstellar space is simulated, and focusing MHD wave (FMW) model is proposed for triggered star formation (SF). Waves from an SF region are trapped by nearby molecular clouds…
Context. Water vapor emission at 22 GHz from masers associated with star-forming regions is highly variable. Aims. We present a database of up to 20 years of monitoring of a sample of 43 masers within star-forming regions. The sample covers…
Accretion onto protostars may occur in sharp bursts. Accretion bursts during the embedded phase of young protostars are probably most intense, but can only be inferred indirectly through long-wavelength observations. We perform radiative…