相关论文: Probing star clusters as cosmic ray factories
Young open clusters are likely sites of cosmic ray acceleration as indicated by recent detections of the TeV gamma-ray sources in the directions of two open clusters (Cyg OB2 and Westerlund 2) and their directional proximity to some…
Young massive clusters (YMCs) are recently formed astronomical objects with unusually high star formation rates. We propose the collision of giant molecular clouds (GMCs) as a likely formation mechanism of YMCs, consistent with the YMC…
Cosmic rays are energetic nuclei that permeate the entire Galactic disk. Their existence requires the presence of powerful particle accelerators. While Galactic supernova explosions may supply the required energy, there is growing evidence…
The currently available empirical evidence on the star formation processes in the extreme, high-pressure environments induced by galaxy encounters, mostly based on high-resolution Hubble Space Telescope imaging observations, strongly…
Whilst young massive clusters (YMCs; $M$ $\gtrsim$ 10$^{4}$ M$_{\odot}$, age $\lesssim$ 100 Myr) have been identified in significant numbers, their progenitor gas clouds have eluded detection. Recently, four extreme molecular clouds…
Massive OB stars play an important role in the evolution of molecular clouds and star forming regions. The OB stars both photo--ionize molecular gas as well as sweep up and compress interstellar gas through winds, ionization fronts, and…
Massive stars are mainly found in stellar associations. These massive star clusters occur in the heart of giant molecular clouds. The strong stellar wind activity in these objects generates large bubbles and induces collective effects that…
During the last two decades, the focus of star formation research has shifted from understanding the collapse of a single dense core into a star to studying the formation hundreds to thousands of stars in molecular clouds. In this chapter,…
We present an analysis of young star clusters (YSCs) that form in the E-MOSAICS cosmological, hydrodynamical simulations of galaxies and their star cluster populations. Through comparisons with observed YSC populations, this work aims to…
The origins of all extra-solar cosmic rays -- both the ultra high-energy and lower energy Galactic variety -- remain unclear. It has been argued that the large scale shocks and turbulence induced by the multiple interacting supersonic winds…
Context. Star clusters are often invoked as contributors to the flux of Galactic cosmic rays and as sources potentially able to accelerate particles to $\sim$PeV energies. The gamma radiation with $E\gtrsim$ TeV recently observed from…
Young massive clusters (YMCs) are dense aggregates of young stars, which are essential to galaxy evolution, owing to their ultraviolet radiation, stellar winds, and supernovae. The typical mass and radius of YMCs are M~10^4 M_sun and R~1…
Young and massive stellar clusters are a potential source of galactic cosmic rays due to at least two acceleration mechanisms. Collective stellar winds from massive stars form a wind-blown bubble with a termination shock at which particle…
Young massive clusters (YMCs) are the most compact, high-mass stellar systems still forming at the present day. The precursor clouds to such systems are, however, rare due to their large initial gas mass reservoirs and rapid dispersal…
Massive stars blow powerful winds and eventually explode as supernovae. By doing so, they inject energy and momentum in the circumstellar medium, which is pushed away from the star and piles up to form a dense and expanding shell of gas.…
Current empirical evidence on the star-formation processes in the extreme, high-pressure environments induced by galaxy encounters (mostly based on high-resolution Hubble Space Telescope observations) strongly suggests that star CLUSTER…
All stars are born in molecular clouds, and most in giant molecular clouds (GMCs), which thus set the star formation activity of galaxies. We first review their observed properties, including measures of mass surface density, Sigma, and…
Star forming regions (SFRs) have been postulated as possible sources of cosmic rays (CRs) in our galaxy. One example of a gamma-ray source associated with an SFR is the Fermi-LAT cocoon, an extended region of gamma-ray emission in the…
Young massive stellar clusters are extreme environments and potentially provide the means for efficient particle acceleration. Indeed, they are increasingly considered as being responsible for a significant fraction of cosmic rays (CRs)…
Massive stars born in star clusters terminate star cluster formation by ionizing the surrounding gas. This process is considered to be prevalent in young star clusters containing massive stars. The Orion Nebula is an excellent example…