Research

   At the center of most galaxies lies an active supermassive black hole. These active galactic nuclei (AGNs) undergo a messy and chaotic process of matter accretion, which can exert a profound influence not only on their immediate surroundings but on the host galaxies as a whole.

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 This intricate, self-regulating process by which the nuclear black holes impact their host ambient medium is known as AGN feedback. AGN feedback is the means by which the active galactic nucleus communicates its presence to the entire host galaxy. In this exchange, galaxies serve as the suppliers, providing the gas and matter necessary for the black hole's sustenance and growth. As the black hole feeds, it inputs energy back into the galactic medium, primarily through radiation, winds, or jets that can reach near the speed of light. 

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   The implications of AGN feedback are twofold: positive feedback can confine and compress gas within the host galaxy, accelerating the formation of stars. Meanwhile, negative feedback can heat and ionize the gas in the galaxy, leading to the quench of star formation and the depletion of the cool gas needed for furthering black hole feeding. Effectively, negative feedback can transform a blue galaxy with hot young stars into a "red and dead" galaxy with an old and passive stellar population.

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    My research focuses on the study of AGN-galaxy feedback through the analysis of deep and multi-wavelength observations of nearby active galaxies. In X-rays, the Chandra X-ray Observatory can resolve the signatures of feedback, providing valuable diagnostic tools to distinguish between the various emission mechanisms at play, such as shocks and photoionization processes. This information is crucial in pinpointing the locations where powerful mass outflows interact with the interstellar medium (ISM), thus indicating where kinematic feedback from AGN-driven outflows is important.

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By combining Chandra's spatial and spectral resolution with narrow-band imaging data from other observatories, such as the Hubble Space Telescope (HST) and ground-based integral field units (IFUs), we obtain a complete, multi-wavelength picture of where shocks occur, and their role in AGN feedback. More than that, now, with the James Webb Space Telescope (JWST), we have a powerful tool to probe feedback using narrow-line emission in the infrared regime, which is unobscured by the dust and gas, which typically dominates galactic nuclei. 

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   As we continue to use data from various observatories, both existing and forthcoming, my goal is to build a comprehensive, multi-wavelength picture of how supermassive black holes interact with their surroundings, illuminating the intricate mechanisms that drive AGN-galaxy feedback in the local Universe.