We investigate the orbital motion of the Quintuplet cluster near the Galactic center with the aim of constraining formation scenarios of young, massive star clusters in nuclear environments. Three epochs of adaptive optics high-angular resolution imaging with the Keck/NIRC2 and VLT/NAOS-CONICA systems were obtained over a time baseline of 5.8 years, delivering an astrometric accuracy of 0.5-1 m...

1. The reconstruction of the 3D-velocities of the clusters of galaxies and their large-scale motions remains one of the central problems of observational cosmology (see [2,7] and references therein). The reason is clear: these properties should contain crucial information on the mechanisms of formation of the filaments and even on more early phases of evolution of the Universe, as well as on th...

We present a result of searching for galaxy clusters that show an indication of global rotation using a spectroscopic sample of galaxies in SDSS and 2dFGRS. We have determined the member galaxies of 899 Abell clusters covered in SDSS and 2dFGRS using the redshift and the positional data of galaxies, and have estimated the ratio of the cluster rotation amplitude to the cluster velocity dispersio...

Using Planck data combined with the Meta Catalogue of X-ray detected Clusters of galaxies (MCXC), we address the study of peculiar motions by searching for evidence of the kinetic Sunyaev-Zeldovich effect (kSZ). By implementing various filters designed to extract the kSZ generated at the positions of the clusters, we obtain consistent constraints on the radial peculiar velocity average, root me...

The measurement of precise galaxy distances by Cepheid observations out to the distance of the Virgo cluster is important for the determination of the Hubble constant. The Virgo cluster is thereby often used as an important stepping stone. The first HST measurement of the distance of a Virgo galaxy (M100) using Cepheid variables provided a value for H 0 = 80(±17) km s −1 (Freedman et al. 1994)....