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Today's Colloquium: Search for a variation of fundamental constants from astronomical observations

Submitter: Wim Ubachs (Amsterdam)
Description: An overview is presented of quasar absorption methods to search for a possible variation of the proton-electron mass ratio mu=m_p/m_e on a cosmological time scale. Details of the analysis of astronomical spectra of molecular hydrogen and carbon monoxide, obtained in the optical regime with large 8--10 m class telescopes, equipped with high-resolution echelle grating based spectrographs, are explained. Another method is that of radio astronomy, where specifically methanol molecules are the target of interest in view of their sensitivity to the varying constant.

Theoretical physics scenarios delivering a rationale for a varying mu will be discussed. Also a recent approach to detect a dependence of the proton-to-electron mass ratio on environmental conditions, such as the presence of strong gravitational fields, will be highlighted. For a recent review: W. Ubachs et al., arXiv:1511.04476

Displayed is the ESO Very Large Telescope at Paranal (left) and the laser system at LaserlaB Amsterdam. Both instruments are used to investigate the spectrum of molecular hydrogen, either at high redshift in the Early Universe, or at zero redshift in the present epoch. Comparison between the result will provide insight in the constancy of fundamental constants.
Copyright: Wim Ubachs (Amsterdam)
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