Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments

Understand

Context: The interaction of the light from astronomical objects with the constituents of the Earth's atmosphere leads to the formation of telluric absorption lines in ground-based collected spectra.

• Correcting for these lines, mostly affecting the red and infrared region of the spectrum, usually relies on observations of specific stars obtained close in time and airmass to the science targets, therefore using precious observing time.
• Aims: We present molecfit, a tool for correcting for telluric absorption lines based on synthetic modelling of the Earth's atmospheric transmission.
• Molecfit is versatile and can be used with data obtained with various ground-based telescopes and instruments.