UVES NGSL Project: telluric lines

HOME | Overview table | Details | Proposal (P79) | telluric line list | RV list | artefacts | quality control plots | data access     External: STIS NGSL page

The list of telluric lines has been derived from the telluric reference spectra. These have been obtained roughly every month or two. They are not intended to provide a template spectrum good enough for telluric line correction. They establish a mash of airmass and PWV content of the atmosphere which is useful for comparison to the NGSL programme stars.

The S/N of the comparison spectra is very high. The spectral types of the comparison stars are early-B so that their spectra are dominated by the stellar continuum. Their few photospheric spectral lines are broadened by fast rotation. These spectra are ideal for determination of a reference catalog of telluric lines. That line list is available here, for the three redmost spectral ranges.

We have decided to mark in our result spectra the telluric absorption features, by thin vertical blue lines centered at the position CENTER_CORR. This is the central wavelength of the telluric line listed as :CENTER (column no. 4) in the line tables, corrected as

CENTER_CORR = :CENTER*(1+(RV_HELIO + RV_SHIFT)/c)

where
- RV_HELIO: heliocentric RV correction
- RV_SHIFT: radial velocity of the star
- c: speed of light

The values for RV_HELIO (per setting) and RV_SHIFT (per target) are collected in the target result tables (e.g. here). Note that, as a consequence of choosing a wavelength scale in the rest system of the respective target, the telluric line system apparently moves forth and back if you compare spectra from different targets.

line list wavelength range
tident_580U.dat 588.5 - 657.5nm
tident_860L.dat 686.5 - 843.3nm
tident_860U.dat 893.0 - 985.0nm

README file for the line lists:

The telluric line tables list parameters of the fits for the telluric line determination. 
They are written by the MIDAS center/gauss command.

:INDEX :START :END :CENTER :INT_START :INT_END :INT_PEAK :INT_FIT :FWHM
=======================================================================

:INDEX		-- index for the lines
:START		-- wavelength of first marking
:END		-- second marking
:CENTER		-- wavelength of gauss fit (LINE POSITION)
:INT_START	-- intensity at first marking (px values)
:INT_END	-- second marking
:INT_PEAK	-- intensity at peak 
:INT_FIT	-- central intensity of fit
:FWHM		-- width of fitted gaussian


Send comments to <Reinhard.Hanuschik@eso.org>  
Last update: 2009-10-05 17:52:37