Active galactic nuclei (AGN), powered by the accretion of matter onto supermassive black holes (SMBHs) at the centres of galaxies, affect their host galaxies and larger scale environment through a process called feedback. AGN feedback is generally invoked in galaxy formation models and simulations to explain the observed correlation between the mass of the SMBHs and various host galaxy properties. A viable feedback mechanism in AGN is outflows. The driving force behind such outflows seen in molecular, atomic and ionised gas, though debated, can have an impact on the interstellar medium (ISM) of their hosts galaxies by inhibiting (negative feedback) or enhancing (positive feedback) star formation. Such outflows affecting star formation through the interaction of radio jets with the ISM in the host galaxies, though known in large massive galaxies are not known in dwarf galaxies. Only recently, there are observational evidences of dwarf galaxies hosting AGN , thereby, challenging theoretical models that generally invoke supernovae feedback in dwarf galaxies. We carried out a systematic investigation on a sample of AGN to find clues to (a) what triggers outflows in AGN, (b) the impact of AGN on the star formation of their hosts and (c) the incidence of AGN feedback in a dwarf galaxy powered by an intermediate mass black hole. Towards this, we used imaging data from the Chandra X-ray observatory, the Ultra-Violet Imaging Telescope on board AstroSat, the Hubble Space Telescope, the Very Large Array, spatially resolved spectroscopic data in the optical, infrared bands from Gemini and MaNGA as well as the sub-mm data from ALMA. We found (a) ionising outflows are prevalent in all types of AGN, (b) while radiation from AGN is the primary driver for outflows, radio jets do play a secondary role in enhancing the gas kinematics over and above that caused by radiation, (c) star formation is quenched in the very central regions of galaxies due to AGN activity, (d) first evidence of jet-ISM interaction at the scale of 10 parcsec in a dwarf AGN NGC 4395 and (e) evidence of AGN and supernova driven feedback in NGC 4395. Details of the results will be discussed.
BGS Office