Centimeter Wave Radio Spectroscopy of Spiral Galaxies: Back to the Big Dishes

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Martha P. HaynesCentimeter wave radio spectroscopy of spiral galaxies back to the big dishesDr. Haynes is using upgraded Arecibo antenna and the Green Bank Telescope to investigate the properties of spiral galaxies over a range of redshifts using the strong emission line in the centimeter range of the radio spectrum. Four main topics are under study: (1) using the 21 cm line in combination with optical imaging to reconstruct the density field in the local universe. Dr. Haynes is studying the systematics of the Tully-Fisher relation, particularly the effects of surface brightness, luminosity and morphology. And the possibility of curvature in the relation itself. Also under investigation is a study of the statistical properties of the velocity field using an expanded sample within the declination band between 15 and +35 degrees.(2) comparing the kinematics of the HI layer derived from synthesis mapping observations. Models obtained from HI synthesis maps are compared with hydrodynamic numerical models of disk galaxies embedded in dark matter potentials.(3) using the Tully-Fisher technique to determine the possibility of evolution of the mass-to-light ratio of galaxies as a function of redshift. This includes the use of the 21 cm line for galaxies with redshifts between 0.08 and 0.33.(4) conducting pilot searches for intergalactic HI and IH maser emission at high redshift.