Talk detail

Participant	Barstow, Martin
Institution	University of Leicester - University Road - Leicester - Leicestershire - United Kingdom

Session	PT4	Accepted	Yes	Order	1	Time	15:15	20'
Talk	Oral abstract	Title	White dwarfs as laboratories for studying the gravitational dependence of the fine-structure constant
Coauthors	Bainbridge, Matthew B; Preval, Simon P; Reindl, Nicole; Ayres, Tom R; Holberg, Jay B; Webb, John K; Barrow, John D; Hu, Jitin;
Abstract	The far-UV spectra of many hot white dwarf stars contain 100s of absorption lines arising from heavy elements such as Fe or Ni. In principle, it is possible to study the relationship between the fine-structure constant and the strong gravitational field by searching for shifts between the observed and laboratory wavelengths of these lines. However, these are challenging observations, as the predicted wavelength shifts are small, requiring high spectral resolution to have a chance of detecting them, and there are many systematic effects of a similar magnitude, e.g. accuracy of the instrumental wavelength calibration and laboratory wavelength, that must be taken into account. We report on our latest work to address these challenges, utilising a low gravity subdwarf as a template for the laboratory wavelengths and making improvements to the analysis methodology. The Hubble Space Telescope and its STIS spectrograph is the only facility capable of delivering data of the necessary resolution and signal-to-noise to carry out the work. We have been making use of selected archival data in our earlier work, but have now successfully obtained new spectra of three white dwarfs that span a range of gravity not available in the archive. We present the latest results from our analysis of these stars.
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