0 Assigned ID: 3554 ----- Attempting Submission 1 (Fri Mar 25 21:06:54 GMT 2022) ----- While AGN feedback has emerged as a key ingredient in galaxy formation and suppressing cooling in X-ray cool cores, heating cannot stop cooling at all times and all spatial scales. Indeed, star formation (SF) is still common in X-ray cool cores around the brightest central galaxies (BCGs). SF in BCGs is the final sink term in the energy balance/transfer in the the multi-phase medium. The relation between radio AGN and SF is an important question in AGN feedback. For strong X-ray cool cores associated with strong radio AGN, besides the studies on ones with strong SF, detailed studies on ones with weak SF is also required for a complete understanding of the feedback cycle. We argue that the closest BCG M87 is the best object for such kind of studies and propose an HST archival study of M87 with the deepest HST data available to any BCG, especially taking advantage of the recently available deep WFC3/UV data. SF indeed happens in M87 but at a low level. These deep HST data, combined with the proximity of M87, present a rare opportunity to study low-level SF in X-ray cool cores, which is impossible in more distant cool cores. Some initial analysis has been finished to reveal a population of UV-bright sources resembling young star clusters. Young star clusters will be identified. Their connection with optical emission-line filaments, soft X-ray clumps, recent AGN shocks and outbursts will be probed. We will constrain the recent star formation history in M87 and link it to the recent history of cooling and AGN outbursts in M87 revealed from the radio and X-ray data. The results will also have general implications for the radio AGN feedback cycles in X-ray cool cores. Our team has rich experience with the HST ACS/WFC data, as well as the stellar population modeling. We also have the track record to study M87 and multi-phase medium in X-ray cool cores. The detailed expertise and background for the project team. ----------------------- HST data analysis: Sun, Waldron Stellar population modeling: Sun, Boselli, Waldron Multi-wavelength analysis: Boselli, Donahue, Forman, Sun, Tremblay Simulations: Churazov, Gaspari Theory: Churazov, Gaspari, Voit ----------------------- This archival grant will support a postdoc to work on this project. The postdoc will spend about nine months on the data analysis, modeling and paper writing. The PI Sun will oversee the project and assist the postdoc on all aspects of the project. Dr. Boselli is the PI of the VESTIGE project. He will provide supporting data and assist us on the data analysis. Mr. Waldron has done initial analysis on the data, including combining the WFC3 data and generating color - magnitude relation. He is finishing his PhD thesis with the HST data on galaxies. He will assist the data analysis. Dr. Forman is the PI of the deep Chandra data and will assist us on interpretation of the HST results. Dr. Gaspari is a world expert in high-resolution hydrodynamical simulations of cool cores and AGN feedback. He will assist the comparison with simulations, including the low level SF in filaments. Dr. Tremblay, Dr. Donahue, Dr. Churazov and Dr. Voit all have rich experience on X-ray cool cores and the associated physics. They will assist us on the interpretation of the HST results. We plan at least one paper from this proposal. Galaxies Supermassive Black Holes and Active Galaxies 0 Regular false false true false false false SUPPORTED