Related papers: Assessing Self-Absorbed Molecular Lines as Tracers…

We revisit the interpretation of blue-excess molecular lines from dense collapsing cores, considering recent numerical results that suggest prestellar core collapse occurs from the outside-in, and not inside-out. We thus create synthetic…

Observations of atomic or molecular lines can provide important information about the physical state of star forming regions. In order to investigate the line profiles from dynamical collapsing massive star forming regions (MSFRs), we model…

Observations of molecular lines are a key tool to determine the main physical properties of prestellar cores. However, not all the information is retained in the observational process or easily interpretable, especially when a larger number…

The evolution of star-forming core analogues undergoing inside-out collapse is studied with a multi-point chemodynamical model which self-consistently computes the abundance distribution of chemical species in the core. For several collapse…

Emission line profiles of tracer molecule H$_2$CO 140 GHz transition from gravitational core collapsing clouds in the dynamic process of forming protostars are calculated, using a simple ray-tracing radiative transfer model. Three…

We discuss the effects of gravitational collapse on the shape of absorption line profiles for low column density (log N(HI) < 14) Lyman Alpha forest clouds and argue by comparison with cosmological simulations that Lyman alpha forest…

We have coupled a chemical model with two dynamical models of collapsing low mass star-forming cores to predict abundances across the core of the commonly used infall tracers, CS and HCO$^+$, at various stages of the collapse. The models…

Some recent results are presented about high redshift molecular absorption lines, namely about chemical abundances of elements, and in particular of water and molecular oxygen. Excitation temperatures of several molecules are found lower…

We use numerical simulations of molecular cloud formation in the colliding flow scenario to investigate the reliability of observational estimates of the angular momenta of early-state, low-mass protostellar cores. We show that, with…

Molecules dominate the cooling function of neutral metal-poor gas at high density. Observation of molecules at high redshift is thus an important tool toward understanding the physical conditions prevailing in collapsing gas. Up to now,…

We investigate general aspects of molecular line formation under conditions which are typical of prestellar cores. Focusing on simple linear molecules, we study formation of their rotational lines by radiative transfer simulations. We…

A fundamental issue in star formation is understanding the precise mechanisms leading to the formation of prestellar cores, and their subsequent gravitationally unstable evolution. To address this question, we carefully construct a suite of…

Stellar core collapse events are expected to produce gravitational waves via several mechanisms, most of which are not yet fully understood due to the current limitations in the numerical simulations of these events. In this paper, we begin…

The core collapse of a massive star at the end of its life can give rise to one of the most powerful phenomena in the Universe. Because of violent mass motions that take place during the explosion, core-collapse supernovae have been…

We consider resonant absorption in a spectral line in the outflowing plasma within several tens of Schwarzschild radii from a compact object. We take into account both Doppler and gravitational shifting effects and re-formulate the theory…

Murphy et al. (2003a, MNRAS, 345, 609) claim to find evidence of cosmological variations of the fine structure constant $\alpha$ in the spectra of intervening QSO absorption line systems. We find that this result is affected by systematic…

Observed molecular clouds often appear to have very low star formation efficiencies and lifetimes an order of magnitude longer than their free-fall times. Their support is attributed to the random supersonic motions observed in them. We…

Eigenmode analysis is one of the most promising methods of analyzing large data sets in ongoing and near-future galaxy surveys. In such analyses, a fast evaluation of the correlation matrix in arbitrary cosmological models is crucial. The…

A detailed study of the absorbing molecular clouds towards the radio source PKS1413+135, at a redshift z=0.247, is reported. Physical conditions are derived for the molecular gas in the frame work of two models: a homogeneous multicomponent…

We have made radio- and millimeter-wavelength interferometric observations of a variety of molecular absorption lines toward the gravitational lens systems B0218+357 and PKS1830-211. The absorption occurs in the lensing galaxies at…