2 papers
math-ph2025
The failure of the Ehlers--Kundt conjecture in the impulsive case
Moriz L. Frauenberger, James D. E. Grant, Roland Steinbauer
In 1962, Ehlers and Kundt conjectured that plane waves are the only class of complete Ricci-flat~\emph{pp}-waves, i.e.\ metrics on of the form \[ ds^2=2du\,dv+dx^2+…
astro-ph.SR2018
TYC 3637-1152-1 - a High Amplitude delta Scuti star with peculiar pulsational properties
Ernst Paunzen, Klaus Bernhard, Moriz Frauenberger +16
In some delta Scuti stars, only one or two radial modes are excited (usually the fundamental mode and/or first overtone mode) and the observed peak-to-peak amplitudes exceed 0.3 ma…