Related papers: Spurious frequencies in the {\it Kepler} short cad…
The advent of space-based missions like $Kepler$ has revolutionized the study of solar-type stars, particularly through the measurement and modeling of their resonant modes of oscillation. Here we analyze a sample of 66 $Kepler$…
The Kepler spacecraft observed the hot subdwarf star PHL 417 during its extended K2 mission, and the high-precision photometric lightcurve reveals the presence of 17 pulsation modes with periods between 38 and 105 minutes. From follow-up…
We consider the Helmholtz transmission problem with piecewise-constant material coefficients, and the standard associated direct boundary integral equations. For certain coefficients and geometries, the norms of the inverses of the boundary…
Currently, we have only limited means to probe the presence of planets at large orbital separations. Foreman-Mackey et al. searched for long-period transiting planets in the Kepler light curves using an automated pipeline. Here, we apply…
Anomalous microwave emission is known to exist in the Perseus cloud. One of the most promising candidates to explain this excess of emission is electric dipole radiation from rapidly rotating very small dust grains, commonly referred to as…
A new theoretical technique for understanding, analyzing and developing optical systems is presented. The approach is statistical in nature, where information about an object under investigation is discovered, by examining deviations from a…
Astrophysical data, in the domains of time, involve a wide range of stellar variability phenomena, among them the magnetic activity of the order of a few hours until the signature of an extra-solar planet which can cover a scale of time of…
Phase resolved observations of planetary bodies allow us to understand the longitudinal and latitudinal variations that make each one unique. Rotational variations have been detected in several types of astronomical bodies beyond those of…
The stellar obliquity of a transiting planetary system can be constrained by combining measurements of the star's rotation period, radius, and projected rotational velocity. Here we present a hierarchical Bayesian technique for recovering…
A Fourier transform analysis of 2.5 million spectra in the Sloan Digital Sky Survey was carried out to detect periodic spectral modulations. Signals having the same period were found in only 234 stars overwhelmingly in the F2 to K1 spectral…
Doppler tracking of interplanetary spacecraft provides the only method presently available for broad-band searches of low frequency gravitational waves. The instruments have a peak sensitivity around the reciprocal of the round-trip…
The HARPS spectrograph is showing an extreme stability close to the m s-1 level over more than ten years of data. However the radial velocities of some stars are contaminated by a spurious one-year signal with an amplitude that can be as…
Some accreting neutron stars and young stars show unexplained episodic flares in the form of quasi-periodic oscillations or recurrent outbursts. In a series of two papers we present new work on an instability that can lead to episodic…
Studying photometric time series in the frequency domain can serve as a means of detecting rotational modulations, measuring asteroseismic modes and even detecting short-period transiting planets. To our knowledge, there is no prior archive…
Kepler-30 is a unique target to study stellar activity and rotation in a young solar-like star accompanied by a compact planetary system. We use about 4 years of high-precision photometry collected by the Kepler mission to investigate the…
Tens of thousands of rotation periods have been measured in the Kepler fields, including a substantial fraction of rapid rotators. We use Gaia parallaxes to distinguish photometric binaries (PBs) from single stars on the unevolved lower…
We search for transits around all known pulsating {\delta} Sct variables (6500 K < Teff < 10 000 K) in the long-cadence Kepler data after subtracting the pulsation signal through an automated routine. To achieve this, we devise a simple and…
We present five new pulsating subdwarf B (sdB) stars discovered by the Kepler spacecraft during the asteroseismology survey phase. We perform time-series analysis on the nearly continuous month-long Kepler datasets of these 5 objects; these…
We present a photometric $J$-band variability study of GU Psc b, a T3.5 co-moving planetary-mass companion (9-13$M_{\rm{Jup}}$) to a young ($\sim$150 Myr) M3 member of the AB Doradus Moving Group. The large separation between GU Psc b and…
As brown dwarfs and young giant planets cool down, they are known to experience various chemical transitions --- for example from CO rich L-dwarfs to methane rich T-dwarfs. Those chemical transitions are accompanied by spectral transitions…