1,115 datasets found

In this Letter we investigate the origin of the Oosterhoff dichotomy in light of recent discoveries related to several ancient merging events of external galaxies with the Milky...

We have assembled 560 recent measurements from the literature of distances of Galactic globular clusters and found revised distance estimates for 154 of the 157 clusters in the...

Based on the SDSS catalog, we have found new close quasar-galaxy pairs. We analyze the radial distribution of quasars from pairs around galaxies of different types. We show that...

Time-series VI CCD photometry of the globular cluster NGC 1261 is employed to study its variable star population. A membership analysis of most variables based on Gaia DR2...

We report an analysis of new V and I CCD time-series photometry of the globular cluster NGC 6934. Through the Fourier decomposition of the RR Lyrae light curves, the mean values...

CCD time-series observations of the central region of the globular cluster NGC 3201 were obtained with the aim of performing the Fourier decomposition of the light curves of the...

New CCD photometry of NGC 6366 has lead to the discovery of some variable stars. Two possible Anomalous Cepheids (or Pop II Cepheids), three long period variables, one SX Phe...

Results of CCD photometry using V and R filters are reported for 33 RR Lyrae stars in M15. Applying the approach of Fourier decomposition of the light curves, the physical...

We report the results of CCD V and R photometry of the RR Lyrae stars known in NGC 4147. The periodicities of most variables are revised and new ephemerides are calculated. The...

Using astrometric techniques developed by Anderson et al., we determine proper motions (PMs) in the ~14.60x16.53arcmin^2^ area of the kinematically "thick-disk" globular cluster...

We present a catalog of 908 objects observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) in fields in the vicinity of M31 and M33, targeted as...

From 1982 January to 1988 October, I used the 76-cm and 91-cm (30-inch and 36-inch) reflectors at McDonald Observatory in West Texas for UBV(RI)c observations of 239 galaxies,...

Omega Centauri (omega Cen) is the Milky Way's most massive globular cluster, and has long been suspected of being the remnant core of an accreted dwarf galaxy. If this scenario...

Globular clusters are some of the oldest bound stellar structures observed in the Universe. They are ubiquitous in large galaxies and are believed to trace intense...

Young star clusters enable us to study the effects of stellar rotation on an ensemble of stars of the same age and across a wide range in stellar mass and are therefore ideal...

Globular clusters (GCs) are proxies of the formation assemblies of their host galaxies. However, few studies exist targeting GC systems of spiral galaxies up to several...

Millisecond pulsars are very likely the main source of gamma-ray emission from globular clusters. However, the relative contributions of two separate emission processes -...

The pixel-to-pixel spectral fitting technique is often used in studies of stellar populations. It enables the user to infer several parameters from integrated light spectra such...

Ancient (>10Gyr) globular clusters (GCs) show chemical abundance variations in the form of patterns among certain elements, e.g. N correlates with Na and anticorrelates with...

Young associations in star-forming regions are stellar systems that allow us to understand the mechanisms that characterize the stars in their early life and what happens around...