Abstract Details
| Name: Silpa Sasikumar Affiliation: Universidad de Concepción, Chile Conference ID: ASI2025_237 Title : Event Horizon and Environs (ETHER) Database: Imaging Jet Bases in the Gold Sample Authors and Co-Authors : Silpa Sasikumar 1, Neil M. Nagar 1, Venkatessh Ramakrishnan 1,2,3, Dhanya G. Nair 1, Joaquin Hernández Yévenes 1, Vicente Arratia 1, Andrea Guerrero 1 Abstract Type : Poster Abstract Category : Galaxies and Cosmology Abstract : Low-luminosity AGNs (LLAGNs) are characterized by low Eddington accretion rates, quasi-spherical accretion inflow in the innermost tens of gravitational radii (R_g), and bipolar relativistic jets launched within 100 R_g of the supermassive black hole (SMBH). LLAGNs vastly outnumber ordinary AGNs, making them vital for demographic studies of structures and physics in the innermost hundreds of R_g, as well as for measurements of BH masses, spins, and shadows. We are currently developing a curated database of potential LLAGN targets for the Event Horizon Telescope (EHT) and the next-generation Event Horizon Telescope (ngEHT) studies: Event Horizon and Environs (ETHER). Originally built for target selection, ETHER leverages the transformative science emerging from M87 and Sgr A* to inform demographic studies of the local SMBH population and potentially resolve more BH shadows. ETHER's large size (~4 million objects, with ~3 million having BH mass estimates), and extensive multi-frequency radio and X-ray flux data and SED information, make it valuable for a wide range of scientific goals. From this parent sample, we have identified a "Gold Sample" consisting of the largest SMBH rings with the brightest estimated EHT fluxes from their jets and accretion flows. This sample, which we have been monitoring using VLBA, GMVA, EHT, and ALMA, covers a range of BH masses, Eddington accretion fractions, jet powers, and orientations. It will help trace the merger and accretion history of SMBHs and their shadows, providing strong and unique tests of gravity. I will introduce the ETHER sample and present preliminary results from modeling the jet bases of the Gold targets. These models will help test theoretical models of jet physics, predict observable properties for ongoing and future EHT observations, test the limits of EHT capabilities, and assess the feasibility of near-future ngEHT observations. |