相关论文: Can molecular clouds live long?

Molecular clouds are the principle stellar nurseries of our universe, keeping them in the focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many…

Most young stars in nearby molecular clouds have estimated ages of 1-2 Myr, suggesting that star formation is rapid. However, small numbers of stars in these regions with inferred ages of >= 5-10 Myr have been cited to argue that star…

We present results from the first three-dimensional calculations ever to follow the collapse of a molecular cloud core (~ 10^{-18} g cm^{-3}) to stellar densities (> 0.01 g cm^{-3}). The calculations resolve structures over 7 orders of…

We present an in-depth case study of three molecular clouds associated with the walls of the Galactic supershells GSH 287+04-17 and GSH 277+00+36. These clouds have been identified in previous work as examples in which molecular gas is…

On galactic scales, the surface density of star formation appears to be well correlated with the surface density of molecular gas. This has lead many authors to suggest that there exists a causal relationship between the chemical state of…

If dark matter (DM) is unstable, in order to be present today, its lifetime needs to be longer than the age of the Universe, t_U ~ 4 10^{17} s. It is usually assumed that if DM decays it would do it with some strength through a radiative…

For a number of starless cores, self-absorbed molecular line and column density observations have implied the presence of large-amplitude oscillations. We examine the consequences of these oscillations on the evolution of the cores and the…

The lifetime of mm size dust grains, such as chondrules, in the nominal solar nebula model is limited to $\sim 10^{5}$ yr due to an inward drift driven by gas drag. However, isotopic and petrological studies on primitive meteorites indicate…

Observations suggest that star formation occurs in only one or two crossing times for a range of scales spanning a factor of 1000. These observations include (1) measurements of embedded cluster ages in comparison with the cloud core…

We present a first attempt to construct an analytic model for a clumped gas and dust disk and apply it to the Galactic Centre. The clumps are described as isothermal spheres partially ionized by the external UV radiation field. The disk…

Stars form within molecular clouds but our understanding of this fundamental process remains hampered by the complexity of the physics that drives their evolution. We review our observational and theoretical knowledge of molecular clouds…

In this paper we investigate the level of star formation activity within nearby molecular clouds. We employ a uniform set of infrared extinction maps to provide accurate assessments of cloud mass and structure and compare these with…

We predict the survival time of initially bound star clusters in the solar neighbourhood taking into account: (1) stellar evolution, (2) tidal stripping, (3) shocking by spiral arms and (4) encounters with giant molecular clouds. We find…

We present the first measurement of the lifetimes of Giant Molecular Clouds (GMCs) in cosmological simulations at $z = 0$, using the Latte suite of FIRE-2 simulations of Milky Way-mass galaxies. We track GMCs with total gas mass $\gtrsim…

Recent observations have demonstrated that giant molecular clouds (GMCs) are short-lived entities, surviving for the order of a dynamical time before turning a few percent of their mass into stars and dispersing, leaving behind an isolated…

In previous contributions, we have presented an analytical model describing the evolution of molecular clouds (MCs) undergoing hierarchical gravitational contraction. The cloud's evolution is characterized by an initial increase in its…

We perform ideal MHD high resolution AMR simulations with driven turbulence and self-gravity and find that long filamentary molecular clouds are formed at the converging locations of large-scale turbulence flows and the filaments are…

We re-examine critically the estimates of the duration of different phases of star formation and the lifetimes of molecular clouds, based on the ages of T-Tauri stars, age spreads of stars in clusters, and statistics of pre-stellar cores.…

The Large Magellanic Cloud is one of the nearest galaxies to us and is one of only few galaxies where the star formation history can be determined from studying resolved stellar populations. We have compiled a new catalogue of ages,…

Recent observations suggest galaxies may ubiquitously host a molecular component to their multiphase circumgalactic medium (CGM). However, the structure and kinematics of the molecular CGM remains understudied theoretically and largely…