# Continuous Cadence Acquisition of the LSST Deep Drilling Fields

## TL;DR

This paper proposes a continuous, 2-4 hour cadence observation strategy for LSST's Deep Drilling Fields to capture rapid stellar variability and improve the understanding of transient phenomena at minute timescales.

## Contribution

It introduces a novel continuous exposure approach for LSST Deep Drilling Fields, enhancing sensitivity to short-period variability and enabling detailed transient analysis.

## Key findings

- Allows detection of variability with periods as short as 32 seconds.
- Improves co-added depth and sensitivity to low-amplitude signals.
- Facilitates interpretation of sparse observations in the main survey.

## Abstract

To extend LSST's coverage of the transient and variable sky down to minute timescales, we propose that observations of the Deep Drilling Fields are acquired in sequences of continuous exposures each lasting 2--4 hours. This will allow LSST to resolve rapid stellar variability such as short-period pulsations, exoplanet transits, ultracompact binary systems, and flare morphologies, while still achieving the desired co-added depths for the selected fields. The greater number of observations of each Deep Drilling Field pushes these mini-surveys deep in terms of both sensitivity to low-amplitude variability and co-added depth. Saving the individual 15-second exposures will yield an effective Nyquist limit of $\approx0.031$ Hz (32 seconds). Resolved short-period variability of targets in these fields will aid the interpretation of sparse observations of a greater number of variables in the main survey. If this cadence strategy conflicts with the science goals of individual Deep Drilling Fields, at least a subset of the additional observations of each field should be obtained continuously. This strategy should also be considered for the proposed Galactic Plane mini survey, which will observe a greater number of stellar variables and transients.