Oral Presentation
Looking for “smoking gun” evidences of AGN-feedback with #RADatHomeIndia citizen science collaboratory.
Presenter: Ananda Hota (UM-DAE Centre for Excellence in Basic Sciences, Mumbai-India & #RADatHomeIndia)
Galaxy merger and AGN-feedback are critical in the current understanding of black hole galaxy co-evolution. However, “smoking gun” evidence of its causality is still missing. “Cosmic leaf blower galaxy”, NGC3801, is a “caught in the act” example we found, where the optically red Kinematically Decoupled Core(KDC) early-type galaxy had a merger 1-2 Gyr back, had the last major episode of star formation 100-500 Myr back, show central ionised gas outflow at 630 km/s, a very young 2.4 Myr sub-galactic size twin radio jet creating X-ray emitting shock shells, expanding at 850 km/s, which would hit the outer gas disk, still forming UV-bright stars, in next 10 Myrs. This galaxy served as an icon for the top 10 science goals of SKA. However, there is no relic-evidence, in radio, if any, to suggest the causal-connection between the AGN radio-jet feedback and the observed decline of star formation, neither in this target nor in any sample of galaxies, so far. Simply put, age of the relic of an AGN-driven outflow has not been found to be of similar time-scale as the age of the last major-episode of star formation. Fortunately, there are radio galaxies with much older relic radio lobes, a few 100 Million years old, nearly a Mpc away from the host elliptical galaxies which are almost always elliptical or remnants of past mergers. Such targets should be explored. On the other hand, we found Speca, one such example of large relic radio lobes hosted by a spiral galaxy. Such Speca-like rare objects, only 6 known so far, suggest creation of spinning super massive black holes capable of launching Mpc-scale jets, without any galaxy merger. New results on such systems with Subaru, XMM and GMRT follow up will be presented. To look for such rare but important objects and relics of AGN-feedback, we have created #RADatHomeIndia collaboratory of professional astronomers and have been training a large network of citizen scientists, a few thousands in number, since 2013. This collaboratory model is a combination of Research, Education and Outreach and different from typical citizen science research (CSR) like Zooniverse or Galaxy Cruise (see https://astro4edu.org/shaw-iau/sessions/citizen-science/ ). With the support of ~30 institutes and a similar number of scientists we have achieved many preliminary discoveries and have followed them up with GMRT observations (GOOD-RAC project). Many results from this will be presented in this workshop. Those include new Speca-like spiral-host radio galaxies, new giant and episodic radio galaxies, never-seen-before relic evidence of AGN-feedback as new ~100 kpc size radio bubble and large radio filaments, and ~60 kpc size one-sided radio jet interacting with the stellar shell in two merging galaxies. Note that as the collaboratory primarily aims at detecting faint fuzzy relic emission as “smoking gun” evidence of AGN-feedback in multi-telescope heterogeneous data, objects found by these trained-citizen scientists would be difficult to discover by automated AI/ML-based methods. This collaboratory method of CSR also has a huge implication for achieving sustainable development goals and human resource development for future mega-science projects.
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