A Comprehensive Census of Roman and Rubin Transient Host Environments from from Low to High Redshift

A Comprehensive Census of Roman and Rubin Transient Host Environments from from Low to High Redshift

Program ID	19076
Science Category	Stellar Physics
Program Type	Analysis
Category	Small
Principal Investigator	Anya Nugent
PI Institution	Harvard-Smithsonian Center for Astrophysics
Co-Investigators	V. Ashley Villar (Harvard-Smithsonian Center for Astrophysics)
Abstract	The Roman High-Latitude Time Domain Survey (HLTDS) and the Rubin Legacy Survey of Space and Time (LSST) will ring in a golden-era of transient astronomy, with HLTDS delivering tens-of-thousands of transients at high-redshift (z>1), and LSST uncovering millions of transients, primarily at lower redshifts. Together, these surveys will enable us to determine how many transient types have evolved throughout the Universe's history and allow us to infer rates of these transients types at higher redshift. However, the majority of these transients will solely have scarce photometric coverage, making their classification and progenitor inference extremely difficult. Their host galaxies will be vital in discerning different transient populations and uncovering their origins, as host stellar population properties (redshift, stellar mass, star formation rate, etc.) offer a unique perspective on transients and their progenitors that is independent of their emission. In this proposal, we seek to use Roman photometric and spectroscopic observations, along with any available Rubin photometry, to build a catalog of Roman and Rubin transient host galaxies and their stellar population properties. Our study will greatly help with early classification of high-redshift Roman transients and understanding how transient environments evolve with redshift. We emphasize that while characterizing host environments is essential for the scientific success of both missions, comprehensive host SED modeling for non-Type Ia supernovae is not currently an objective of any Roman PIT or WFS team. Our program is therefore necessary to bridge this gap and achieve the full discovery potential of this golden-era.