High-Precision Calibration of Astronomical Spectrographs with Laser Frequency Combs
Dr Michael Murphy
Centre for Astrophysics and Supercomputing, Swinburne University of Technology
Friday, 9 November 2007, 3.30pm, EN101, (Ground Floor, EN Building), Hawthorn.
Femtosecond frequency combs have recently revolutionised the standards
and metrology fields. As the name suggests, they provide a "picket fence"
of laser modes spaced equally in frequency space and cover a wide
frequency range. In astronomy, there are many applications where we
need precisely calibrated spectrographs and/or where we require
long-term stability (over decades) of relative frequency measurements.
By recording a frequency comb spectrum simultaneously with our
astronomical object spectrum, we might be able to obtain an absolute
frequency scale which will enable spectra from different times and
different instruments to be compared reliably. I will outline some practical
problems involved with building a astronomical comb system, outline current
efforts to overcome these and discuss some of the scientific goals which
would become feasible or benefit enormously by having a spectrograph
calibrated with a frequency comb.
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