High mass X-Ray binaries (HMXBs) are two body systems that consist of a nuclear burning star accreting matter onto a compact object (CO) such as a neutron star (NS) or black hole (BH). Stellar material from the donor heats up as it falls into the deep potential well of the accretor, emitting blackbody radiation with a characteristic X-Ray spectrum. There are two separate processes through which...

Empirical constraints on reionization require galactic ionizing photon escape fractions fesc & 20%, but recent high-resolution radiation-hydrodynamic calculations have consistently found much lower values ∼ 1–5%. While these models have included strong stellar feedback and additional processes such as runaway stars, they have almost exclusively considered stellar evolution models based on singl...

High quality infrared spectra of active galaxies including the stellar absorption features of Si at 1.59 μm, CO(6,3) at 1.62 μm, and CO(2,0) at 2.29 μm are used to measure the stellar mass to light ratio at 1.65 μm (M/LH) and investigate the occurrence of circum–nuclear starbursts. We find that old and powerful starbursts are relatively common in obscured AGNs (5 objects out of 13) while absent...

– 2 – Early-type galaxies exhibit thermal and molecular resonance emission from dust that is shed and heated through stellar mass loss as a subset of the population moves through the AGB phase of evolution. Because this emission can give direct insight into stellar evolution in addition to galactic stellar mass loss and ISM injection rates, we conducted a program to search for this signature em...

The Class A stellar engine (also known as a Shkadov thruster) is a spherical arc mirror, designed to use the impulse from a star’s radiation pressure to generate a thrust force, perturbing the star’s motion. If this mirror obstructs part of the stellar disc during the transit of an exoplanet, then this may be detected by studying the shape of the transit light curve, presenting another potentia...

The use of polarimetric techniques is nowadays widespread among solar and stellar astronomers. However, notwithstanding the recommandations that have often been made about the publication of polarimetric results in the astronomical literature, we are still far from having a standard protocol on which to conform. In this paper we review the basic definitions and the physical significance of the ...