Studying Galactic Weak Feedbacks With Multi-phase Gas

Galaxies can be regarded as factories where gas is converted into stars,black holes and metals.During these processes,the feedback from stars and black holes can eject massive materials into interstellar medium(ISM)and even circumgalactic medium(CGM),which can affect the subsequent star formation and change the metallicity of CGM.Literature works mainly focused on strong feedback from active galactic nuclei(AGN)and massive stars,few of them have discussed the effects of week feedback and weak outflows.In this work,we have made use of datacubes from multi-phase gas to understand the effects of feedback from low-luminosity AGN and weak outflows.Firstly,we have statistically studied the regions in host galaxies that can be heavily affected by AGN in the massive integral field unit(IFU)survey of SDSS-IV/Ma NGA.Based on the photoionization model,the ratio of different spectral lines depends on the properties of the radiation field.Thus it could be applicable to separate different regions dominated by different feedback from certain line ratios.In optical datacube,spectrum diagnosis from BPT diagram can be used to separate the star-forming and AGN regions.From SDSS-IV/Ma NGA,we have selected 152 AGN with extended narrow line region(NLR).After correcting the effects of dust extinction and point spread function(PSF),we find a good log-linear relation between the size of NLR and the luminosity of [O III] with a slope of 0.42 ± 0.02.It indicates that a typical local low-luminosity Seyfert without heavy obscuration in the center has the potential to ionize the gas up to several kiloparsec(kpc).Besides,our model favors a clumpy NLR rather than the homogeneous one.At the same time,we also identify the signatures of weak outflow from the kinematic residuals.The basic ideal is that regular rotating gas component can be subtractedby the model while non-rotating structure like inflows and outflows would be left in the residual.We firstly applied this method to a nearby radio galaxy – Centaurus A and a luminous infrared galaxy(LIRG)– IRAS 18293-3413.We used the tilted-ring model to fit the regular rotating gas.In Centaurus A,many complex structures have been found in its residual.But in IRAS 18293-3413,we do find two strong outflow candidates from its kinematic residual.Both of them show a relatively straight orientation(extending to nearly 2 kpc in their physical size)and their velocity dispersions are higher than other regions.Based on our current results,the kinematic residual can be a promising method to find the weak outflows.