Kilonova Detectability with Wide-Field Instruments

TL;DR

This study evaluates the capabilities of 13 wide-field instruments to detect kilonovae across various distances, using extensive simulations, and offers a framework to interpret non-detections for understanding ejecta properties.

Contribution

It provides a comprehensive assessment of current and future wide-field instruments' ability to detect kilonovae and introduces a framework to analyze non-detections for ejecta property inference.

Findings

Roman Space Telescope can detect kilonovae up to z~1 within a day.

Several ground-based and space-based instruments can observe kilonovae out to z~0.1.

A new framework is proposed to infer ejecta properties from non-detections.

Abstract

Kilonovae are ultraviolet, optical, and infrared transients powered by the radioactive decay of heavy elements following a neutron star merger. Joint observations of kilonovae and gravitational waves can offer key constraints on the source of Galactic $r$-process enrichment, among other astrophysical topics. However, robust constraints on heavy element production requires rapid kilonova detection (within $\sim 1$ day of merger) as well as multi-wavelength observations across multiple epochs. In this study, we quantify the ability of 13 wide field-of-view instruments to detect kilonovae, leveraging a large grid of over 900 radiative transfer simulations with 54 viewing angles per simulation. We consider both current and upcoming instruments, collectively spanning the full kilonova spectrum. The Roman Space Telescope has the highest redshift reach of any instrument in the study, observing kilonovae out to $z \sim 1$ within the first day post-merger. We demonstrate that BlackGEM, DECam, GOTO, the Vera C. Rubin Observatory's LSST, ULTRASAT, and VISTA can observe some kilonovae out to $z \sim 0.1$ ($\sim$475 Mpc), while DDOTI, MeerLICHT, PRIME, $Swift$/UVOT, and ZTF are confined to more nearby observations. Furthermore, we provide a framework to infer kilonova ejecta properties following non-detections and explore variation in detectability with these ejecta parameters.