The HYPERMUCHFUSS Campaign -- an undiscovered high velocity population

TL;DR

The HYPERMUCHFUSS campaign aims to discover high velocity subluminous stars and white dwarfs, potentially revealing a larger population of hyper-velocity stars and massive compact companions through spectroscopic surveys.

Contribution

This study introduces an efficient selection technique and reports on the progress of a survey targeting high velocity stellar populations using multiple telescopes.

Findings

Identification of promising high velocity star candidates

Progress in survey nearing completion

Potential discovery of a larger hyper-velocity star population

Abstract

We present an overview and a status report of HYPERMUCHFUSS (HYPER velocity or Massive Unseen Companions of Hot Faint Underluminious Stars Survey) aiming at the detection of a population of high velocity subluminous B stars and white dwarfs. The first class of targets consists of hot subdwarf binaries with massive compact companions, which are expected to show huge radial velocity variations. The second class is formed by the recently discovered hyper-velocity stars, which are moving so fast that the dynamical ejection by a supermassive black hole seems to be the only explanation for their origin. Until now only one old hyper-velocity star has been found, but we expect a larger population. We applied an efficient selection technique for hot subdwarfs and white dwarfs with high galactic restframe velocities from the \emph{SDSS} spectral data base, which serve as first epoch observations for our campaign with the ESO VLT and NTT in Chile, the 3.5 m telescope at DSAZ observatory (Calar Alto) in Spain and the WHT on La Palma. The survey is nearing completion and provides us with promising candidates which will be followed up to measure their RV-curves to uncover massive companions or prove their nature as HVS.