ESO future facilities to probe fundamental physical constants

Abstract

Following HARPS, two ESO projects are aimed at the ambitious goal of trying to reach the highest possible precision in measuring the radial velocityof astronomical sources. ESPRESSO spectrograph, located at the incoherent combined 4VLT focus, but able to work either with one or all VLT units, and CODEX for E-ELT will mark ESO roadmap towards the cm s-1level of precision and possiblyto an unlimited temporal baseline. By providing photon noise limited measures their promise is to improve the present limits in the variability of fundamental physical constants by one and two orders of magnitude, respectively, thus allowing for instance to verify the claim discussed at this conference by JohnWebb of a possible spatial dipole in the variation of the fine structure constant. © Springer-Verlag Berlin Heidelberg 2011.