Speaker
Description
New ideas in unification theories suggest space-time variations of
dimensionless physical constants may exist and that they might be within
reach of current instrumental precision available from the world's best
observatories. State-of-the-art observations already hint at such an
effect. If confirmed, fundamental revisions in standard physics would be
required.
Accurate calibrations are of course crucial in searches for space-time
variations of dimensionless physical constants using spectroscopic
observations from the world's best observatories. Several recent studies
reveal wavelength distortions in optical echelle spectrographs. These
are not yet understood and they have not yet been measured using the
actual science data used to derive constraints on space-time variation
of alpha (critical since they appear to vary with time). In this work we
study the impact of such distortions on measurements of the fine
structure constant, alpha, observed at high redshift using
high-resolution quasar spectroscopy and show that whilst long-range
wavelength-scale distortions do exist, and hence contribute an
additional systematic error, these systematics (measured directly from
the science exposures themselves) are small and unlikely to explain the
spatial variations of alpha reported recently.
