Astronomical Spectroscopy: Calibration Sources for the Near Infrared

摘要

The European Southern Observatory (ESO) operates a multitude of telescopes and instruments at its La Silla Paranal Observatory in Chile. The most powerful ones are the four 8-m telescopes of the Very Large Telescope (VLT). ESO is currently studying an Extremely Large Telescope (ELT) with a diameter of the primary mirror of 42 m. This telescope will make use of various techniques of adaptive optics (AO) to counter the perturbing effect of Earth's atmosphere. Due to the wavelength dependent performance of AO the European ELT (E-ELT) will be most powerful in the near-infrared (IR) domain. A collaboration of ESO and the US Institute for Standards and Technology (NIST) has successfully established wavelength standards in the emission spectrum of Th-Ar hollow cathode lamps for high resolution spectroscopy. This has been a major advancement for near-IR astronomy, which has traditionally relied on atmospheric features for wavelength calibration. ESO and NIST report on joint efforts to identify and establish the best sources for wavelength calibration for the 2nd generation of VLT instrument and for the E-ELT. To this end we are studying the near-IR spectra of various elements. With the focus of astronomy moving toward IR wavelengths the astronomical community will have a need for a large amount of atomic and molecular data in order to perform the scientific analysis of their data. It will be essential that the long-standing and fruitful collaboration between astrophysics and the atomic and molecular physics community continues in the future.