Related papers: Is the massive young cluster Westerlund I bound?
We present H\alpha images of an ionized nebula surrounding the M2-5Ia red supergiant (RSG) W26 in the massive star cluster Westerlund 1. The nebula consists of a circumstellar shell or ring ~0.1pc in diameter and a triangular nebula ~0.2pc…
After the stars of a new, embedded star cluster have formed they blow the remaining gas out of the cluster. Especially winds of high mass stars and definitely the on-set of the first super novae can remove the residual gas from a cluster.…
A pilot study with the powerful new backend of the Westerbork Synthesis Radio Telescope (WSRT) of two galaxy clusters at z=0.2 has revealed neutral hydrogen emission from 39 galaxies. The volume probed for each cluster is 1.7x10^4 Mpc^3,…
Most stars form in compact, dense embedded clusters with memberships ranging from a dozen stars to many millions of stars. Embedded clusters containing more than a few hundred stars also contain O stars that disrupt the nebula abruptly.…
After the stars of a new, embedded star cluster have formed they blow the remaining gas out of the cluster. Especially winds of massive stars and definitely the on-set of the first supernovae can remove the residual gas from a cluster. This…
The nuclear star cluster of the Milky Way is a unique target in the Universe. Contrary to extragalactic nuclear star clusters, using current technology it can be resolved into tens of thousands of individual stars. This allows us to study…
The residual gas within newly formed star clusters is expelled through stellar feedback on timescales ~ 1 Myr. The subsequent expansion of the cluster results in an unbinding of a fraction of stars before the remaining cluster members can…
There is growing evidence that a treatment of binarity amongst OB stars is essential for a full theory of stellar evolution. However the binary properties of massive stars - frequency, mass ratio and orbital separation - are still poorly…
B,V CCD frames have been used to derive surface brightness profiles for NGC 3201 out to ~18 arcmin. A total of 857 radial velocities with median precision ~1 km/s for 399 member giants have been used to trace the velocity dispersion profile…
New optical MK classification spectra have been obtained for 14 OB star candidates identified by Comeron et al. (2002) and presumed to be possible members of the Cyg OB2 cluster. All 14 candidate OB stars observed are indeed early-type…
The clusters of young stars in massive star-forming regions show a wide range of sizes, morphologies, and numbers of stars. Their highly subclustered structures are revealed by the MYStIX project's sample of 31,754 young stars in nearby…
We present a detailed analysis of the pre-main-sequence (PMS) population of the young star cluster Westerlund~2 (Wd2), the central ionizing cluster of the HII region RCW 49, using data from a high resolution multi-band survey with the…
We confirm the reality of the recently discovered Milky Way stellar cluster $\textit{Gaia}$ 1 using spectra acquired with the HERMES and AAOmega spectrographs of the Anglo-Australian Telescope. This cluster had been previously undiscovered…
Aims: Based on our well-determined sample of open clusters in the all-sky catalogue ASCC-2.5 we derive new linear sizes of some 600 clusters, and investigate the effect of mass segregation of stars in open clusters. Methods: Using…
We have made CO(J=2-1) observations towards the HII region RCW 49 and its ionizing source, the rich stellar cluster Westerlund 2 (hereafter Wd2), with the NANTEN2 sub-mm telescope. These observations have revealed that two molecular clouds…
We report the results of our analysis of the publicly available data obtained by the Large Area Telescope (LAT) on board of the Fermi satellite towards the direction of the young massive star cluster Westerlund 2. We found significant…
During the last decade, hundreds of young massive cluster candidates have been detected in the disk of the Milky Way. We investigate one of these candidates, Mercer 81, which was discovered through a systematic search for stellar…
We use high-resolution near-infrared spectroscopy from Keck Observatory to measure the stellar velocity dispersions of 19 super star clusters (SSCs) in the nuclear starburst of M82. The clusters have ages on the order of 10 Myr, which is…
We present the results from the dynamical analysis of the cluster of galaxies RX J0152-1357, which shows a complex structure in its X-ray emission, with two major clumps in the central region, and a third clump in the Eastern region. Our…
We have selected a sample of 88 nearby (z<0.1) galaxy clusters from the SDSS-DR4 with redshift information for the cluster members. We have derived global properties for each cluster, such as their mean recessional velocity, velocity…