5 papers · 1 filter
Selection of ThAr lines for wavelength calibration of echelle spectra and implications for variations in the fine-structure constant
M. T. Murphy, P. Tzanavaris, J. K. Webb +1
Echelle spectrographs currently provide some of the most precise and detailed spectra in astronomy, the interpretation of which sometimes depends on the wavelength calibration accu…
High-precision wavelength calibration of astronomical spectrographs with laser frequency combs
M. T. Murphy, Th. Udem, R. Holzwarth +8
We describe a possible new technique for precise wavelength calibration of high-resolution astronomical spectrographs using femtosecond-pulsed mode-locked lasers controlled by stab…
The connection between metallicity and metal-line kinematics in (sub-)damped Lyman-alpha systems
M. T. Murphy, S. J. Curran, J. K. Webb +2
A correlation between the metallicity, [M/H], and rest-frame MgII equivalent width, EW, is found from 49 DLAs and strong sub-DLAs drawn from the literature over the redshift range…
Revision of VLT/UVES constraints on a varying fine-structure constant
Michael T. Murphy, John K. Webb, Victor V. Flambaum
We critically review the current null results on a varying fine-structure constant, alpha, derived from VLT/UVES quasar absorption spectra, focusing primarily on the many-multiplet…
Deep Searches for High Redshift Molecular Absorption
S. J. Curran, J. K. Webb, M. T. Murphy +1
Millimetre-band scans of the frequency space towards optically dim quasars is potentially a highly efficient method for detecting new high redshift molecular absorption systems. He…