Deriving Iodine-free spectra for high-resolution echelle spectrographs. (arXiv:1903.11718v1 [astro-ph.IM])
<a href="http://arxiv.org/find/astro-ph/1/au:+Diaz_M/0/1/0/all/0/1">Matías R. Díaz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shectman_S/0/1/0/all/0/1">Stephen A. Shectman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Butler_R/0/1/0/all/0/1">R. Paul Butler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jenkins_J/0/1/0/all/0/1">James S. Jenkins</a>
We describe a new method to derive clean, iodine-free spectra directly from
observations acquired using high-resolution echelle spectrographs equipped with
iodine cells. The main motivation to obtain iodine-free spectra is to use
portions of the spectrum that are superimposed with the dense forest of iodine
absorption lines, in order to retrieve lines that can be used to monitor the
magnetic activity of the star, helping to validate candidate planets. In short,
we provide a straight-forward methodology to clean the spectra by using the
forward model used to derive radial velocities, the Line Spread Function
information plus the stellar spectrum without iodine to reconstruct and
subtract the iodine spectrum from the observations. We show our results using
observations of the star $tau$ Ceti acquired with the PFS, HIRES and UCLES
spectrographs, reaching an iodine-free spectrum correction at the $sim$1% RMS
level. We additionally discuss the limitations and further applications of the
method.
We describe a new method to derive clean, iodine-free spectra directly from
observations acquired using high-resolution echelle spectrographs equipped with
iodine cells. The main motivation to obtain iodine-free spectra is to use
portions of the spectrum that are superimposed with the dense forest of iodine
absorption lines, in order to retrieve lines that can be used to monitor the
magnetic activity of the star, helping to validate candidate planets. In short,
we provide a straight-forward methodology to clean the spectra by using the
forward model used to derive radial velocities, the Line Spread Function
information plus the stellar spectrum without iodine to reconstruct and
subtract the iodine spectrum from the observations. We show our results using
observations of the star $tau$ Ceti acquired with the PFS, HIRES and UCLES
spectrographs, reaching an iodine-free spectrum correction at the $sim$1% RMS
level. We additionally discuss the limitations and further applications of the
method.
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