Collaborative Research: WoU-MMA: Searches After Gravitational-waves Using Arizona's Observatories (SAGUARO)

The first detection in 2017 of both gravitational waves and light from a neutron star merger opened a new era of ‘multi-messenger’ astrophysics. It provided direct evidence for the origin of short gamma ray bursts, cosmic heavy element production (like gold and platinum), and the launching of relativistic outflows from compact object mergers (like neutron stars and black holes). When neutron stars merge, they can produce electromagnetic light, including explosive ‘kilonova’ emission that is visible in the optical and near-infrared for only a few days. With only one such detection thus far, however, there is still much to learn by identifying the systems that produce gravitational wave events and studying them intensely. The investigators will run an electromagnetic observing campaign associated with gravitational wave detector observations. The search incorporates two discovery telescopes and a set of 1-10m telescopes for immediate and frequent monitoring of new kilonovae. As part of this project, the investigators have developed a course at a Hispanic Serving Community College, which will introduce students of all skill levels to basic python programming and to give them a view of what a STEM/academic future looks like. The investigators will carry out comprehensive discovery and follow-up observations of gravitational wave events during the fourth Advanced Detector run (O4) and beyond, taking advantage of a new discovery machine (the Bok 2.3-m telescope on Kitt Peak). Crucially, they will use newly upgraded software, which includes pre-vetting of incoming transients within the gravitational wave localization region (by cross-matching with other transient surveys and relevant catalogs) and tools to enable same-night triggering of photometric and spectroscopic resources on viable counterparts. Ultimately the team will measure the color and spectroscopic evolution of a sample of new kilonovae to disentangle projection effects and measure physical properties such as the composition, ejecta mass and velocity. It is only with a sample of counterparts that a true physical picture of kilonovae can be obtained. The investigators will also carry out deep observations of the host galaxies and stellar environs of kilonovae, which will constrain associations to globular clusters and quantify offsets between the merger site, host galaxy star formation, and other galaxy properties. These observations will constrain the viable pathways that lead to compact object mergers. This project advances the goals of the Windows on the Universe Big Idea. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.