Elmo Tempel (Tartu Observatory, Estonia)

Orientation of galaxies in filaments: 3D photometrical modelling of galaxies and filamentary structure in the SDSS
When Apr 17, 2012 from 03:00 PM to 04:00 PM
What
  • Special Seminar
Where SH, Seminar room
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We search for and find evidence that the spin axes of galaxies relative to their host filaments are not randomly distributed. Similarly to dark matter haloes in N-body simulations, spin axes of fainter galaxies are weakly aligned parallel to filaments, whereas more luminous galaxies have orthogonal alignment. To find the spin axes of galaxies, we used the 3D photometrical model of galaxies. This model allows to estimate relatively accurately the inclination angle of galaxies, whereas in 2D models the inclination angle is degenerate with the disc thickness. To search for filaments in the cosmic web, we use a three-dimensional object point process, which help to find the filaments and also defines the orientation of a filament.

In my talk, firstly, I describe the 3D photometrical model of galaxies and how accurately it restores the structural parameters and inclination angles of galaxies. Secondly, I describe the method that we used to find filaments and I demonstrate how good are the detected filaments. Finally, I combine these two results and search for correlation between filaments and spin axes of galaxies.