MaNGA galaxies with off-centered spots of enhanced gas velocity dispersion
Off-centered spots of the enhanced gas velocity dispersion, σ, are revealed in some galaxies from the Mapping Nearby Galaxies at Apache Point Observatory survey (MaNGA). Aiming to clarify the origin of the spots of enhanced σ, we examine the distributions of the surface brightness, the line-of-sight velocity, the oxygen abundance, the gas velocity dispersion, and the Baldwin-Phillips-Terlevich spaxel classification in seven galaxies. We find that the enhanced σ spots in six galaxies can be attributed to a (minor) interaction with a satellite. Three galaxies in our sample have a very close satellite (the separation in the sky plane is comparable to the optical radius of the galaxy). The spots of enhanced σ in those galaxies are located at the edge of the galaxy close to the satellite. The spots of enhanced σ in three other galaxies are related to bright spots in the photometric B band within the galaxy, which can be due to the projection of a satellite in the line of sight of the galaxy. The oxygen abundances in the spots in these three galaxies are reduced. This suggests that the low-metallicity gas from the satellite is mixed with the interstellar medium of the disk, that is, the gas exchange between the galaxy and its satellite takes place. The spectra of the spaxels within a spot are usually H※ II-region-like, suggesting that the interaction (gas infall) in those galaxies does not result in appreciable shocks. In contrast, the spot of the enhanced σ in the galaxy M-8716-12703 is associated with an off-centered active galactic nucleus-like radiation distribution. One can suggest that the spot of the enhanced σ in the M-8716-12703 galaxy is different in origin, or that the characteristics of gas infall in this case differs from that in other galaxies. © ESO 2021. ; L.S.P acknowledges support within the framework of the program of the NAS of Ukraine Support for the development of priority fields of scientific research (CPCEL 6541230)". BC, JN and MG are supported by AYA2014-58861-C3-1-P. I.A.Z acknowledges support by the National Academy of Sciences of Ukraine under the Research Laboratory Grant for young scientists No. 0120U100148. AMP is supported by AYA2017-88007-C3-2, MDM2017-0737 (Unidad de Excelencia Maria de Maeztu, CAB). JMV and SDP acknowledge financial support from the Spanish Ministerio de Economia y Competitividad under grants AYA2016-79724-C4-4-P and PID2019-107408GBC44, from Junta de Andalucia Excellence Project P18-FR-2664, and also acknowledge support from the State Agency for Research of the Spanish MCIU through the `Center of Excellence Severo Ochoa' award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). SDP is grateful to the Fonds de Recherche du Quebec - Nature et Technologies. The work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University and Russian Science Foundation, grant no. 20-12-00105. This research has made use of the NASA/IPAC Extragalactic Database, which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr).Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy O ffice of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. ; Peer reviewed