Related papers: Evidence for dynamical changes in Betelgeuse using…
GW190521 is a remarkable gravitational-wave signal on multiple fronts: its source is the most massive black hole binary identified to date and could have spins misaligned with its orbit, leading to spin-induced precession -- an…
If stars at the lower end of the main sequence are responsible for the microlensing events observed in the Galactic bulge, then light from the lensing star contributes to the observed brightness. The background and lensing stars generally…
As one of the most influential experiments on the development of modern macroscopic theory from Newtonian mechanics to Einstein's special theory of relativity, the phenomenon of light dragging in a moving medium has been discussed and…
We present the serendipitous discovery of eclipse-like events around the massive white dwarf SDSS J152934.98+292801.9 (hereafter J1529+2928). We selected J1529+2928 for time-series photometry based on its spectroscopic temperature and…
We apply a new non-parametric Bayesian method for reconstructing the evolution history of the equation-of-state $w$ of dark energy, based on applying a correlated prior for $w(z)$, to a collection of cosmological data. We combine the latest…
A variety of high-energy events can take place in the seconds leading up to a binary neutron-star merger. Mechanisms involving tidal resonances, electrodynamic interactions, or shocks in mass-loaded wakes have been proposed as instigators…
High-cadence, multiwavelength observations have continuously revealed the diversity of tidal disruption events (TDEs), thus greatly advancing our knowledge and understanding of TDEs. In this work, we conducted an intensive optical-UV and…
The giant flare of December 27, 2004 from SGR 1806-20 represents one of the most extraordinary events captured in over three decades of monitoring the gamma-ray sky. One measure of the intensity of the main peak is its effect on X- and…
We investigate the 2018-2019 main outburst and the subsequent mini-outbursts of the black hole low-mass X-ray binary MAXI J1820+070 using optical/ultraviolet data from the Las Cumbres Observatory (LCO), the American Association of Variable…
We study the classical dynamics of a binary stars when there is an interchange of mass between them. Assuming that one of the star is more massive than the other, the dynamics of the lighter one is analyzed as a function of its time…
Several works have recently shown that there is an important extra line-broadening (usually called $macroturbulence$) affecting the spectra of O and B Supergiants that adds to stellar rotation. So far, the only (very recent) physical…
The mechanisms responsible for heating the extended atmospheres of early-M spectral-type supergiants are poorly understood. So too is the subsequent role these mechanisms play in driving the large mass-loss rates of these stars. Here we…
We present a high-resolution spectral analysis of Betelgeuse (M2 Iab). Between 1998 January and 1999 March four spatially resolved raster scans (http://cfa-www.harvard.edu/cfa/ep/pressrel/alobel0100.html) have been obtained with the STIS on…
New facilities and technologies have advanced our understanding of massive stars significantly over the past 30 years. Here I introduce a new large survey of massive stars using VLT-FLAMES, noting the target fields and observed binary…
We present results of a long-term optical, UV and X-ray study of variability of the nearby changing-look (CL) Seyfert NGC 1566 which was observed with the Swift Observatory from 2007 to 2020. We summarize our previously published…
Close, compact, hierarchical, multiple stellar systems, i.e., multiples having an outer orbital period from months to a few years, comprise a small, but continuously growing group of the triple and multiple star zoo. Many of them consist of…
We present the results of seven years of multicolour photometric monitoring of a sample of 31 $\gamma$-ray bright blazars using the RINGO3 polarimeter on the Liverpool Telescope from 2013--2020. We explore the relationships between…
The existence of an additional body around a binary system can be detected by the help of the light-travel time effect. Due to the motions of binary and the companion stars around the common mass center of the ternary system, the light-time…
We study the time variations of the cycles of 20 active stars based on decades-long photometric or spectroscopic observations. A method of time-frequency analysis, as discussed in a companion paper, is applied to the data. Fifteen stars…
We present the light curve of an unusual variable object, OGLE #7, detected during the OGLE search for microlensing events. After one season of being in a low, normal state, the star brightened by more than 2~mag with a characteristic…