相关论文: The Starburst Cluster Westerlund 1: The Initial Ma…

We present velocity dispersion measurements of 20 Local Group stellar clusters (7 < log(age [yrs]) < 10.2) from integrated light spectra and examine the evolution of the stellar mass-to-light ratio, Upsilon_*. We find that the clusters…

We undertake a systematic analysis of the early (< 0.5 Myr) evolution of clustering and the stellar initial mass function in turbulent fragmentation simulations. These large scale simulations for the first time offer the opportunity for a…

The goal of this study is to determine a distance to Westerlund 1 independent of the characteristics of the stellar population and to study its neutral environment, using observations of atomic hydrogen. The HI observations are taken from…

We present a uniform analysis of the stellar initial mass function (IMF) from integrated light spectroscopy of 15 compact stellar systems (11 globular clusters in M31 and 4 ultra compact dwarfs in the Virgo cluster, UCDs) and two brightest…

Westerlund 1 is one of the most massive young clusters known in the Local Group, with an age of 3-5 Myr. It contains an assortment of rare evolved massive stars, such as blue, yellow and red supergiants, Wolf-Rayet stars, a luminous blue…

A growing fraction of Simple Stellar Population (SSP) models, in an aim to create more realistic simulations capable of including stochastic variation in their outputs, begin their simulations with a distribution of discrete stars following…

It has been shown recently that the dynamical V-band mass-to-light ratios of compact stellar systems with masses from 10^6 to 10^8 Solar masses are not consistent with the predictions from simple stellar population (SSP) models. Top-heavy…

The initial mass function (IMF) is one of the most important functions in astrophysics because it is key to reconstructing the cosmological matter cycle, understanding the formation of super-massive black holes, and deciphering the light…

Theoretical arguments and indirect observational evidence suggest that the stellar initial mass function (IMF) may evolve with time, such that it is more weighted toward high mass stars at higher redshift. Here we test this idea by…

We present analysis of HST U,V,I, and Halpha images of the peculiar Local Group irregular galaxy IC 10. The images are used to determine the nature of the stellar products in a portion of the recent starburst in this galaxy. We identified…

We study the cluster population in a region of 3.2x3.2 kpc^2 in the inner spiral arms of the intergacting galaxy M51, at a distance of about 1 to 3 kpc from the nucleus, based on HST--WFPC2 images taken through five broadband and two…

We report the discovery of an extraordinarily massive young cluster of stars in the Galaxy, having an inferred total initial cluster mass comparable to the most massive young clusters in the Galaxy. Using {\it IRMOS}, {\it 2MASS}, and {\it…

High-dynamic range radio observations of Westerlund 1 are presented that detect a total of 21 stars in the young massive stellar cluster, the richest population of radio emitting stars known for any young massive galactic cluster in the…

The properties of 939 star clusters in the Large and Small Magellanic Clouds were determined from ground-based CCD images in UBVR passbands. The areal coverage was extensive, corresponding to 11.0 sq-kpc in the LMC and 8.3 sq-kpc in the…

The current status of both the observational evidence and the theory of the stellar initial mass function (IMF) is reviewed, with particular attention to the two basic, apparently universal features shown by all observations of nearby…

The stellar initial mass function (IMF) is commonly interpreted to be a scale-invariant probability density distribution function (PDF) such that many small clusters yield the same IMF as one massive cluster of the same combined number of…

The Hydra I cluster offers an excellent opportunity to study and compare the relic old stellar populations in the core of its two brightest galaxies. In addition, the differing kinematics of the two galaxies allows a test of the local…

We present a method for investigating variations in the upper end of the stellar Initial Mass Function (IMF) by probing the production rate of ionizing photons in unresolved, compact star clusters with ages <~10 Myr and with different…

The formation of the stellar mass within galaxy cluster cores is a poorly understood process. It features the complicated physics of cooling flows, AGN feedback, star formation and more. Here, we study the growth of the stellar mass 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)…