K2: Background Survey -- the search for undiscovered transients in Kepler/K2 data

TL;DR

This paper explores the potential of the K2 mission data to identify and analyze transient astronomical events in background pixels, enabling high cadence surveys and rate estimations for short-lived transients.

Contribution

It introduces a method to analyze background pixels in K2 data for transient detection, demonstrating the recovery of known events and estimating transient rates.

Findings

Successfully recovered KSN 2015K and SN 2018oh

Demonstrated high cadence transient detection in background pixels

Estimated rates for transients with lifetimes ≤1 day

Abstract

The K2 mission of the Kepler Space Telescope offers a unique possibility to examine sources of both Galactic and Extra-galactic origin with high cadence photometry. Alongside the multitude of supernovae and quasars detected within targeted galaxies, it is likely that Kepler has serendipitously observed many transients throughout K2. Such events will likely have occurred in background pixels, coincidentally surrounding science targets. Analysing the background pixels presents the possibility to conduct a high cadence survey with areas of a few square degrees per campaign. We demonstrate the capacity to independently recover key K2 transients such as KSN 2015K and SN 2018oh. With this survey, we expect to detect numerous transients and determine the first comprehensive rates for transients with lifetimes $\leq1$ day.