Related papers: A Useful Approximation for Computing the Continuum…
The purpose of this work is to review the observational properties of Be/X-ray binaries. The open questions in Be/X-ray binaries include those related to the Be star companion, that is, the so-called "Be phenomenon", such as, timescales…
Context. The binary B5V star BD+31?643 exhibits a disk-like structure detected at optical wavelengths. Even though the feature is well centered on the star, it has been argued, based on Spitzer observations, that the feature is a filament…
Analysis of radial velocities of two narrow absorption components in the Mg II 4481 A line demonstrated that the secondary of the Be star omicron Cas is indeed a close binary system composed of two B7 stars orbiting each other with a period…
We have developed a complete theory for the calculation of the observed Stokes parameters for radiation emitted from the surface of a rapidly rotating neutron star (NS) using the oblate Schwarzschild approximation. We accounted for the…
The Be star \delta\ Scorpii is an interesting binary system, whose primary companion created a circumstellar disk after the periastron passage of the secondary in 2000, being since then classified as Be. This work presents the results of a…
A simple model to study boson stars is to consider these stellar objects as quantum systems of $N$ identical self-gravitating particles within a non-relativistic framework. Some results obtained with point-like particles are recalled as…
The eclipsing binary epsilon Aur is unique in being a very long-period binary involving an evolved, variable F star and a suspected B main-sequence star enshrouded in an opaque circumstellar disk. The geometrical arrangement is that the…
Debris disks give us the unique opportunity to probe the properties of small $\mu$m-sized particles, allowing us to peer into the constituents of their parent bodies, young analogs of comets and asteroids of our solar system. In the past,…
Well over 700 exoplanets have been detected to date. Only a handful of these have been observed directly. Direct observation is extremely challenging due to the small separation and very large contrast involved. Imaging polarimetry offers a…
This white paper highlights compact object and fundamental physics science opportunities afforded by high-throughput broadband (0.1-60 keV) X-ray polarization observations. X-ray polarimetry gives new observables with geometric information…
Classical Be stars are well known to eject mass, but the details governing the initial distribution and evolution of this matter into a disk are poorly constrained by observations. By combining high-cadence spectroscopy with contemporaneous…
Microlensing of extended stellar sources in the LMC and Galaxy by low mass lenses can produce variable polarisation. The characteristics of the polarisation and flux profiles can provide considerable information about the lens geometry, and…
This paper presents optical UBVRI broadband photo-polarimetry of the EXPORT sample obtained at the 2.5m Nordic Optical Telescope. The database consists of multi-epoch photo-polarimetry of 68 pre-main-sequence and main-sequence stars. An…
Observational data for dusty comets are summarized and systemized. The dependence of the linear polarization on various parameters (the phase angle, wavelength, etc.) is analyzed. An ensemble of aligned spheroidal particles having various…
Our goal is to study the physical properties of the circumstellar environment of young stellar objetcs (YSOs). In particular, the determination of the scattering mechanism can help to constrain the optical depth of the disk and/or envelope…
We present the first experimental results on the use of a thick aligned Si crystal acting as a quarter wave plate to induce a degree of circular polarisation in a high energy linearly polarised photon beam. The linearly polarised photon…
High spectral-resolution Br-gamma VLTI/AMBER observations of classical Be stars reveal complex visibility, phase, and closure phase profiles, which were not seen in previous lower-resolution data. They present new challenges for the…
X-ray polarimetry is now providing a new way to look at the high energy sky. The addition of two observables, polarization fraction and angle, reveals crucial new information on the structure of accretion flows and magnetic fields in…
Current models that explain giant (type II) X-ray outbursts in Be/X-ray binaries (BeXB), are based on the idea of highly distorted disks. They are believed to occur when a misaligned and warped disk becomes eccentric, allowing the neutron…
A birefringent universe could show itself through a rotation of the plane of polarisation of the cosmic microwave background photons. This is usually investigated using polarisation $B$ modes, which is degenerate with miscalibration of the…