相关论文: Distance and age of the massive stellar cluster We…

The typically large distances, extinction, and crowding of Galactic supermassive star clusters have so far hampered the identification of their very low mass members, required to extend our understanding of star and planet formation, and…

Deep Hubble Space Telescope (HST) observations with WFPC2 of the nearby globular cluster NGC 6752 have allowed us to obtain accurate photometry for the cluster white dwarfs (WD). A sample of local WDs of known trigonometric parallax and…

Westerlund 1 is the most important starburst cluster in the Galaxy due to its massive star content. We have performed BVIc and JKs photometry to investigate the initial mass function (IMF). By comparing the observed color with the spectral…

The diverse massive stellar population in the young massive cluster Westerlund 1 (Wd~1) provides an ideal laboratory to observe and constrain mass-loss processes throughout the transitional phase of massive star evolution. A set of high…

We report the discovery of an X-ray pulsar in the young, massive Galactic star cluster Westerlund 1. We detected a coherent signal from the brightest X-ray source in the cluster, CXO J164710.2-455216, during two Chandra observations on 2005…

Context. Westerlund I is the richest young cluster currently known in our Galaxy, making it one of the most massive clusters for which we can resolve the individual stars even in the crowded centre. This makes it an ideal target to assess…

Westerlund 1 is a young, massive Galactic starburst cluster that contains a rich coeval population of Wolf-Rayet stars, hot- and cool-phase transitional supergiants, and a magnetar. We use spectroscopic and photometric observations of the…

Context: Star clusters, composed of stars born from the same molecular cloud, serve as invaluable natural laboratories for understanding the fundamental processes governing stellar formation and evolution. Aims: This study aims to…

We have used new parallax measurements, obtained by the Hipparcos satellite, of fifteen nearby, metal-poor stars to re-define the subdwarf main-sequence. All of these stars have parallaxes determined to an accuracy of at least 12 %.…

Evidence is presented indicating that the young star cluster Westerlund~2 lies $d_{\odot}\sim3.0$ kpc in the direction of Carina. The distance is tied partly to new $UBVRI_c$ photometry and revised spectral classifications for cluster…

Westerlund 2 (Wd2) is the central ionizing star cluster of the \ion{H}{2} region RCW~49 and the second most massive young star cluster (${\rm M} = (3.6 \pm 0.3)\times 10^4\,{\rm M}_\odot$) in the Milky Way. Its young age ($\sim2\,$Myr) and…

An unsettled question concerning the formation and distribution of massive stars is whether they must be born in massive clusters and, if found in less dense environments, whether they must have migrated there. With the advent of wide-area…

With a dynamical mass M_dyn ~ 1.3x10e5 M_sun and a lower limit M_cl>5x10e4 M_sun from star counts, Westerlund 1 is the most massive young open cluster known in the Galaxy and thus the perfect laboratory to study massive star evolution. We…

We analyze 4\,050 wide binary star systems involving a white dwarf (WD) and usually a main sequence (MS) star, drawn from the large sample assembled by \citet[][hereafter, T20]{Tian_2020}. Using the modeling code BASE-9, we determine the…

Aims. The properties of the early-type stars in the core of the Westerlund2 cluster are examined in order to establish a link between the cluster and the very massive Wolf-Rayet binary WR20a as well as the HII complex RCW49. Methods.…

We present a new independent determination for the age of one of the oldest open clusters, NGC 188: $6.41 \pm 0.33$ Gyr. We utilize a novel approach where we jointly fit the radial velocities (RVs) and spectral energy distributions (SED) of…

A new X-ray, {\it UBVR}$I_c$, and {\it JHK$s$} study of the young cluster Westerlund 2 was undertaken to resolve discrepancies tied to the cluster's distance. Existing spectroscopic observations for bright cluster members and new multi-band…

Analyzing the dynamical state of nearby young massive star clusters is essential understanding star cluster formation and evolution during their earliest stages. In this work we analyze the stellar and gas kinematics of the young massive…

Context. Distances to evolved massive stars in the Milky Way are not well constrained by Gaia parallaxes due to their brightness and variability. This makes it difficult to determine their fundamental stellar parameters, such as radius or…

Massive stellar clusters have recently been hypothesised as candidates for the acceleration of hadronic cosmic rays up to PeV energies. Previously, the H.E.S.S. Collaboration has reported about very extended $\gamma$-ray emission around…