Astronomy and Astrophysics Seminars

Precise radio astronomical and laboratory spectroscopy

by Prof. Alexander V. Lapinov (Institute of Applied Physics of the RAS, Nizhny Novgorod, Russia)

Tuesday, November 14, 2017 from to (Asia/Kolkata)
at DAA Seminar ( A269 )
Modern radio astronomical observations could provide an accuracy for the centers of molecular lines ~ 1 m/s in a Doppler velocity scale or better than 1 kHz at mm – submm wavelengths. At the same time the traditional laboratory spectroscopy at these frequencies has typical accuracy ~ 30 – 100 kHz. It will be shown how the use of nonlinear Lamb-dip spectroscopy can not only increase the accuracy by several orders but also resolve hyperfine  structure within the observed Doppler profiles. For laboratory unstable molecules sufficiently high accuracy can be obtained in a cold molecular jets. In some cases very precise frequencies were measured from pure  astronomical observations. As a result the use of precise molecular line data can give us not only information about small systematic motions in star forming regions but also provide very precise upper limits on variations of some fundamental constants.