Detection and characterisation of oscillating red giants: first results
  from the TESS satellite
  Since the onset of the `space revolution' of high-precision high-cadence
photometry, asteroseismology has been demonstrated as a powerful tool for
informing Galactic archaeology investigations. The launch of the NASA TESS
mission has enabled seismic-based inferences to go full sky -- providing a
clear advantage for large ensemble studies of the different Milky Way
components. Here we demonstrate its potential for investigating the Galaxy by
carrying out the first asteroseismic ensemble study of red giant stars observed
by TESS. We use a sample of 25 stars for which we measure their global
asteroseimic observables and estimate their fundamental stellar properties,
such as radius, mass, and age. Significant improvements are seen in the
uncertainties of our estimates when combining seismic observables from TESS
with astrometric measurements from the Gaia mission compared to when the
seismology and astrometry are applied separately. Specifically, when combined
we show that stellar radii can be determined to a precision of a few percent,
masses to 5-10% and ages to the 20% level. This is comparable to the precision
typically obtained using end-of-mission Kepler data
