Investigating Feedback Process In Nearby Galaxies With Spatially Resolved Spectroscopic Observations

Using spatially resolved spectra from SDSS-IV/MaNGA survey,we studied the impact of AGN feedback and stellar feedback on galaxy evolution.In our study on AGN feedback,we focus on its impact on the star formation in AGN host galaxies.We use BPT diagram to identify the ionizing source of gas in different regions of nearly 5000 MaNGA galaxies and select 14 galaxies with AGN dominating ionizing source in their central regions and on-going star formation in their disks.All of these galaxies are disk dominated spiral galaxy or barred spiral galaxies.We also select star forming control galaxies with similar stellar mass,morphology and disk star forming activity for each of our sample AGN.Using the Ha emission line flux obtained by MaNGA and simple stellar population fitting result from Pipe3D,we measured the star formation rate and stellar mass in 5 bins within 1.5 effective radii of our sample and controls and compared their difference in specific star formation rate in these regions.In our analysis we found the specific star formation rate within 0.6 effective radii of our sample AGNs is systematically lower than the average of their control galaxies.Our test reveal that the possibility of reproducing similar or lower central specific star formation rate as our sample galaxies from a sample of matched normal star forming galaxies is low.For the region within 0.3 effective radii and between 0.3 and 0.6 effec-tive radii,the reproduction rate is 0.76%and 3.5%,respectively.This result indicates that star forming activity in the centers of our sample AGNs is mildly suppressed.We consider the suppression of central star formation in MaNGA AGN sample compared to normal star forming galaxies suggests the existence of negative feedback from AGN on star formation in disk galaxies.Negative feedback has been suggested to be a key physical process in the evolution of merging systems and massive elliptical galaxies in previous studies,while our discovery indicates that it could also regulate the growth of disk dominated spiral galaxies under secular evolution.We also find a unique dwarf starburst galaxy with stellar mass,star formation rate and gas phase metallicity similar to high redshift star forming galaxies in MaNGA sam-ple.In the data analysis process,we notice the asymmetric emission line profile with broadening in the blue side in spectra from the southeast of the central starburst region,which indicates the existence of high velocity ionized gas outflow in the galaxy.We perform 2 component gaussian fitting to the asymmetric emission line profiles,decom-pose a broad,blue shifted component and measure its kinematical properties and spatial distribution.The broad component could still be seen at distance up to 8kpc from the central starburst and the centroid velocity is very likely exceeding the escape velocity of the host dark matter halo of the dwarf starburst galaxy.If further confirmed,this could provide direct evidence of the impact of stellar feedback on dwarf galaxies under common physical conditions in early Universe.