Análise da influência ambiental sobre galáxias de núcleo ativo usando o levantamento MaNGA

Abstract

We examined the dependency between nuclear activity in galaxies and the environment in which they are located. Using data from the MaNGA survey from the Sloan Digital Sky Survey IV, we analyzed the gas kinematics of 62 active galaxies, along with 109 galaxies from a control sample without nuclear activity, but otherwise similar to the sample of active galaxies with regard to morpho- logy, stellar mass and redshift. The maps of stellar velocity and emission line velocity for Hα, Hβ, [OIII]λ5007 and [NII]λ6583, as well as their fluxes, were obtained through the GANDALF software. With the purpose of isolating the contribution from radial motions, the stellar velocity maps were used to produce purely rotational models of thin disk with the DiskFit sofware. Those models were then subtracted from the emission line velocity maps, so that the residual maps represent the radial mo- tion contribution. The contribution from non-circular gas motion both for active and control galaxies was compared with a series of parameters that characterize the environment in which each galaxy is located: the environmental luminous density in four scale factors (1,5 Mpc, 3 Mpc, 6 Mpc and 10 Mpc), the richness of the group to which it belongs, and the galaxy velocity in the frame of reference of its parent cluster. We have found mostly a very small dependence of the intensity of non-circular gas motions in the sample galaxies on the environmental properties. This low environmental sen- sitivity is similar for AGN and control galaxies, so that both active and non-active galaxies are, by and large, indistinguishable with regard to radial gas motions. Analyzing Strong AGN separately, we noted some positive correlation between the occurrence of radial gas motions with the environmental density, while for Weak AGN these motions are more important in low density regions. However, analyzing only the regions close to the center of the sample galaxies, these correlations become less evident, suggesting that only the peripheral gas of the sample galaxies is directly affected by the envi- ronment. Our results suggest that either the excess of non-circular gas motions in AGN as compared to non-active galaxies is very low, or the active phase of the galaxies occurs in a much later period than eventual environmentally driven radial gas motions.