Related papers: The most massive stars in the Arches cluster
We present ultraviolet, optical, near-infrared, Spitzer mid-infrared, and radio images of 14 radio-selected objects in M 33. These objects are thought to represent the youngest phase of star cluster formation. We have detected the majority…
The evolution of massive stars is still partly unconstrained. Mass, metallicity, mass loss and rotation are the main drivers of stellar evolution. Binarity and magnetic field may also significantly affect the fate of massive stars. Our goal…
Strong lensing offers a precious opportunity for studying the formation and early evolution of super star clusters that are rare in our cosmic backyard. The Sunburst Arc, a lensed Cosmic Noon galaxy, hosts a young super star cluster with…
We present a quantitative study of the stellar and wind properties of massive stars in the compact star forming region SMC-N81. Non-LTE spherically extended atmosphere models including line-blanketing have been computed with the code CMFGEN…
We have used deep ACS/WFC images of M33 to check nature of extended objects detected by the ground based survey of Zloczewski et al. (2008). A total of 24 candidates turned out to be genuine compact stellar clusters. In addition we detected…
A small set of chemically old stars that appear young by their independently derived masses has been detected. These are so-called $\alpha$-rich young stars. For a sample of 51 red-giant stars, for which spectra are available from…
We have made a new survey of emission-line stars in the W5E HII region to investigate the population of PMS stars near the OB stars by using the Wide Field Grism Spectrograph 2 (WFGS2). A total of 139 H-alpha emission stars were detected…
We present the results of an abundance analysis for a sample of stars with $-4<$[Fe/H]$<-2$. The data were obtained with the HIRES spectrograph at Keck Observatory. The set includes 28 stars, with effective temperature ranging from 4800 to…
(abridged) We propose the new designation ``WNH'' for luminous Wolf-Rayet (WR) stars of the nitrogen sequence with H in their spectra. These are commonly called WNL stars (e.g., WN7h), but this new shorthand avoids confusion because there…
High-resolution observations in the near infrared show star clusters around the active galactic nucleus (AGN) of the Seyfert 1 NGC2110, along with a 90 x 35 pc bar of shocked gas material around its nucleus. These are seen for the first…
Observations in the near-infrared (NIR) allow a detailed study of young stellar clusters in grand-design spiral galaxies which in visual bands often are highly obscured by dust lanes along the arms. Deep JHK-maps of 10 spirals were obtained…
As a young massive cluster in the Central Molecular Zone, the Arches cluster is a valuable probe of the stellar Initial Mass Function (IMF) in the extreme Galactic Center environment. We use multi-epoch Hubble Space Telescope observations…
We present a CCD-based photometric survey covering 870 sq. arcmin in a young stellar cluster around the young multiple star sigma Orionis. Our survey limiting R, I, and Z magnitudes are 23.2, 21.8, and 21.0, respectively. From our…
We present a near-infrared study of the candidate star cluster Mercer 81, located at the centre of the G338.4+0.1 HII region, and close to the TeV gamma-ray source HESS 1640-465. Using HST/NICMOS imaging and VLT/ISAAC spectroscopy we have…
We propose the Wind of Fast Rotating Massive Stars scenario to explain the origin of the abundance anomalies observed in globular clusters. We compute and present models of fast rotating stars with initial masses between 20 and 120 Msun for…
The lensed Sunburst Arc ($z = 2.369$) hosts a young ($\sim2$--$4\,\rm Myr$), massive ($M_\star \sim 10^7\,M_\odot$), compact ($R_{\rm eff} \sim 8\,\rm pc$) Lyman-continuum (LyC) leaking super star cluster, which powers a compact ($< 10\,\rm…
We discuss HST FOS ultraviolet spectroscopy and NICMOS near-infrared photometry of four young super star clusters in the central region of the irregular starburst galaxy NGC 1569. The new observations coupled with previous HST WFPC2…
Mechanisms involved in the star formation process and in particular the duration of the different phases of the cloud contraction are not yet fully understood. Photometric data alone suggest that objects coexist in the young cluster NGC6530…
Context: The very young sigma Orionis cluster (about 3 Ma) is a cornerstone for the understanding of the formation of stars and substellar objects down to planetary masses. However, its stellar population is far to be completely known.…
We present infrared spectroscopy of the Antennae Galaxies (NGC 4038/4039) with NIRSPEC at the W. M. Keck Observatory. We imaged the star clusters in the vicinity of the southern nucleus (NGC 4039) in 0.39" seeing in K-band using NIRSPEC's…