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SUMMARY:Possible Variation of Fundamental Constants: the impact of recentl
 y uncovered systematic errors - Jonathan Whitmore (Swinburne)
DTSTART:20140620T103000Z
DTEND:20140620T113000Z
UID:TALK52527@talks.cam.ac.uk
CONTACT:Martin Haehnelt
DESCRIPTION:The metal absorption lines found in high resolution QSO spectr
 a have been at the forefront of measurements of several fundamental dimens
 ionless constants of nature. These measurements are made by comparing the 
 relative wavelength spacings of absorption lines found of QSO spectra. The
  fine-structure constant (alpha) and the mass ratio of the proton to elect
 ron (mu) are two fundamental constants that have been measured to a relati
 ve precision of a few parts per million in the redshift range ~0.5--4.0. T
 hey thus require careful wavelength calibration. \n\nThe high resolution e
 chelle spectrographs UVES and HIRES on the telescopes VLT and Keck (respec
 tively) have provided the measurements resulting in evidence of a change i
 n the value of alpha over cosmological time. Measurements of alpha in hund
 reds of absorption systems in a study combining data (153 measurements on 
 VLT and 141 measurements on Keck)\, have led to a proposed spatial dipole 
 across the sky (King\, et al.\, 2012). My research has recently uncovered 
 several long-range wavelength calibration distortions that have direct imp
 lications for alpha and mu measurements taken with each spectrograph. I wi
 ll present some preliminary results on the effect that these systematic er
 rors have on previously published results.\n
LOCATION:Sackler Lecture Theatre\, IoA
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