Instrumental polarization in the focal plane of telescopes. 2: Effects induced by seeing
This work quantifies the influence of the terrestrial atmosphere on the instrumental polarization (IP) of telescopes. Our numerical simulations show that seeing...
Magnetic Fields in M-dwarf Members of the Pleiades Open Cluster Using APOGEE Spectra
Average magnetic field measurements are presented for 62 M-dwarf members of the Pleiades open cluster, derived from Zeeman-enhanced Fe I lines in the H band. A...
Non-local thermodynamic equilibrium line profiles, rotation, and magnetic fields in seven DA white dwarfs
Non-LTE calculations of H-alpha line profiles are presented and applied to derive rotational velocities from high-resolution spectra of DA white dwarfs. This...
Observed differences between large and small sunspots
We confirm recent results about the differences in temperature and magnetic field strength between the umbra of large and small sunspots. Five Stokes I- and V...
The age decay of stellar magnetic activity in MS field solar-type stars
The age decay of two indicators of the stellar magnetic activity (λ2800 Mg II emission flux and λ10830 He I equivalent width) have been studied for field solar...
The magnetic field of the Ap star Epsilon UMa was measured using the Zeeman-Doppler Imaging method. Ultrahigh S/N polarized profiles of the 4923 A magnetically...
The Origin of Weakened Magnetic Braking in Old Solar Analogs
The rotation rates of main-sequence stars slow over time as they gradually lose angular momentum to their magnetized stellar winds. The rate of angular momentum...