Related papers: Four years' interferometric observations of Galact…
A new observing mode for the Palomar Testbed Interferometer was developed in2002-2003 which enables differential astrometry at the level of 20 micro-arcseconds for binary systems with separations of several hundred milli-arcseconds (mas).…
The space-time correlations of streams of photons can provide fundamentally new channels of information about the Universe. Today's astronomical observations essentially measure certain amplitude coherence functions produced by a source.…
We present the analysis of photometric and spectroscopic data of two classical Cepheids, FN Aquilae and V1344 Aquilae. Based on the joint treatment of the new and earlier radial velocity data, both Galactic Cepheids have been found to be a…
Many hot subdwarf stars show composite spectral energy distributions indicative of cool main sequence companions. Binary population synthesis (BPS) models demonstrate such systems can be formed via Roche lobe overflow or common envelope…
Orbits of 55 visual binary stars are computed using recent speckle interferometry data from the SOAR telescope: 33 first-time orbits and 22 revisions of previous orbit calculations. The orbital periods range from 1.4 to 370 years, the…
GAIA astrometric mission of ESA will be very efficient in discovering binary and multiple stars with any orbital period, from minutes to millions of years. Main parameters of the revised mission design are presented. Next we estimate the…
We report the detection of 1143 variable stars towards the Galactic bulge, including 320 previously uncatalogued variables, using time-series photometry extracted from data obtained with the VIMOS imager at the Very Large Telescope.…
V350 Sgr is a classical Cepheid suitable for mass determination. It has a hot companion which is prominent in the ultraviolet and which is not itself a binary. We have obtained two high resolution echelle spectra of the companion at orbital…
We report on the discovery of Cepheids in the spiral galaxy NGC 2841, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. NGC 2841 was observed over 12 epochs using the F555W filter,…
Imaging Atmospheric Cherenkov Telescopes have long been viewed as potential light collectors to be used for long baseline optical intensity interferometry observations. Intensity interferometry, as implemented with Cherenkov telescopes, is…
We present the results of our 2nd radial velocity monitoring campaign, carried out with the \'Echelle spectrograph FLECHAS at the University Observatory Jena in the course of the Gro{\ss}schwabhausen binary survey between December 2016 and…
Our long term aim is to derive model-independent stellar masses and distances for long period massive binaries by combining apparent astrometric orbit with double-lined radial velocity amplitudes (SB2). We follow-up ten O+O binaries with…
We present the Catalog of Cepheids from the SMC which contains data for 2049 objects detected in the 2.4 square degree area of central parts of the SMC. For each object period, BVI photometry, astrometry, and R_21, \phi_21 parameters of the…
We analyse all potential combinations of Galactic Cepheids and open clusters (OCs) in the most up-to-date catalogues available. Isochrone fitting and proper-motion calcula- tion are applied to all potential OC{Cepheid combinations. Five…
We present observations of the galactic cepheids eta Aql and zeta Gem. Our observations are able to resolve the diameter changes associated with pulsation. This allows us to determine the distance to the Cepheids independent of photometric…
The Gaia celestial reference frame (Gaia-CRF) will benefit from a close assessment with independent methods, such as Very Long Baseline Interferometry (VLBI) measurements of radio stars at bright magnitudes. However, obtaining full…
Classical Cepheids in open clusters are key ingredients for stellar population studies and the characterization of variable stars, as they are tracers of young and massive populations and of recent star formation episodes. Cluster Cepheids…
We outline a proposal to use the Kepler spacecraft in two-wheel mode to monitor a handful of young associations and open clusters, for a few weeks each. Judging from the experience of similar projects using ground-based telescopes and the…
We present a census of eclipsing binary systems with classical Cepheid as a component. All such systems known were found in the OGLE collection of classical Cepheids in the Magellanic System. We extend the list of potential candidates…
We have obtained an HST STIS ultraviolet high dispersion Echelle mode spectrum the binary companion of the double mode classical Cepheid Y Car. The velocity measured for the hot companion from this spectrum is very different from reasonable…