Probing the magnetism of the upper solar chromosphere requires measuring and modeling the scattering polarization produced by anisotropic radiation pumping in UV spectral lines. Here we apply PORTA (a novel radiative transfer code) to investigate the hydrogen Lyα line in a three-dimensional model of the solar atmosphere resulting from a state of

We present three giant stars from the ongoing Penn State–Toruń Planet Search with the Hobby–Eberly Telescope, which exhibit radial velocity (RV) variations that point to the presence of planetary-mass companions around them. BD+49 828 is a M=1.52+/- 0.22 {{M}ȯ } K0 giant with a m sin i=1.6-0.2+0.4 {{M}J} minimum mass companion in a = 4.2+0.32‑0.2

We present empirical constraints on the influence of stellar bars on the fueling of active galactic nuclei (AGNs) out to z = 0.84 using a sample of X-ray-selected AGNs hosted in luminous non-interacting face-on and moderately inclined disk galaxies from the Chandra COSMOS survey. Using high-resolution Hubble Space Telescope imaging to identify bars

Jet ejection by accreting black holes is a mass invariant mechanism unifying stellar and supermassive black holes (SMBHs) that should also apply for intermediate-mass black holes (IMBHs), which are thought to be the seeds from which SMBHs form. We present the detection of an off-nuclear IMBH of ˜5 × 104 M⊙ located in an unusual spiral arm of the

The initial mass function (IMF) of early-type galaxies (ETGs) has been found to feature systematic variations by both dynamical and spectroscopic studies. In particular, spectral line strengths, based on gravity-sensitive features, suggest an excess of low-mass stars in massive ETGs, i.e. a bottom-heavy IMF. The physical drivers of IMF variations

We study the mid-egress eclipse timing data gathered for the cataclysmic binary HU Aquarii during the years 1993-2014. The (O-C) residuals were previously attributed to a single ˜7 Jupiter mass companion in ˜5 au orbit or to a stable two-planet system with an unconstrained outermost orbit. We present 22 new observations gathered between 2011 June