The role of non-axisymmetric structures on formation of the oxygen abundance distribution in disk galaxies

Data: 
11/04/2018 - 14:00 - 15:00
Local: 
Auditório IAG, Bloco G

The role of non-axisymmetric structures on formation of the oxygen abundance distribution in disk galaxies

 

Igor Zinchenko

Main Astronomical Observatory (Ukraine)


The relation between radial oxygen abundance gradient and other parameters of a galaxy, such as mass, Hubble type, presence of a bar, etc., remains unclear despite of the large amount of observational data obtained during last years. We investigate the possible dependence of the oxygen abundance gradient and the local oxygen abundance in the disk galaxies from CALIFA DR3 survey on the presence of the non-axisymmetrical structures (bar/spirals) and other parameters, such as mass, size, color index, and central brightness of the galaxy.
We adopt Fourier amplitude A2 of the surface brightness as quantitative characteristic of the strength of non-axisymmetric structures in a galactic disk in addition to commonly used morphologic division for A, AB, B types based on Hubble classification. We consider parametric mass--local metallicity relation, which takes into account influence of the disk size, color index g-r in the SDSS bands, central surface brightness of the disk, and bar/spiral pattern strength simultaneously. This approach allows to distinguish changes of the local oxygen abundance caused by each parameters even when oxygen abundance depends on many parameters simultaneously. We find that there is no significant impact of the non-axisymmetric structures such as a bar and/or spiral patterns on the local oxygen abundance and radial oxygen abundance gradient of the disk galaxies. Meanwhile, galaxies with higher mass exhibit flatter oxygen abundance gradients. We show that the oxygen abundance in the central part of galaxy depends neither on the optical radius R25 nor the color g-r and the surface brightness of the galaxy, but outside the central part the oxygen abundance increases with increase of the g-r value and surface brightness.