RSAA Colloquia / Seminars / Feast-of-Facts: Friday, 05 May 2017, 14:00-14:20; Duffield Lecture Theatre

Anastasia Ponomareva

"How important are resolved rotation curves for the Tully-Fisher relation study?"

The statistical properties of the Tully-Fisher relation provide important constraints for semi-analytical models and numerical simulations of galaxy formation and evolution. Over the past decades, the scatter in the Tully-Fisher relation has been decreased significantly by accurate photometric measures in the NIR bands. However, the small measurement errors on total luminosity can no longer explain the observed scatter. Therefore, we abandon the classical concept of the Tully-Fisher relation as a correlation using the width of global HI profile and consider instead the internal kinematics of gas in galaxies. We implement an improved kinematic measure by deriving high quality rotation curves, taking into account warps and streaming motions in the disk due to spiral arms or a bar. As a result, our studies show that besides the wavelength dependence, statistical properties of the Tully-Fisher relation are highly sensitive to the internal kinematics of gas.