The Effect of "Roll-Drift" in ACS/WFC Images

TL;DR

This paper investigates the 'roll-drift' effect in ACS/WFC images caused by loss of lock events in Hubble Space Telescope, quantifying its impact and establishing a threshold for data quality assessment.

Contribution

It introduces a method to quantify roll-drift effects and provides a threshold to help users identify affected data efficiently.

Findings

Quantified the impact of roll-drift on image data.

Established a threshold for data affected by roll-drift.

Provided a practical tool for data quality assessment.

Abstract

In 2024, due to some operational changes, the Hubble Space Telescope began exhibiting undeclared loss of lock events. This loss of lock can result in the smearing out of light from the target field during an exposure, which leads to data degradation, which in turn may require data to be retaken. In this work, we investigate this `roll-drift' effect in ACS/WFC images. We quantify the impact of roll-drift on measurable parameters in data by using simulations and existing data reduction techniques. We identify a threshold of one such measurable parameter beyond which data may likely be affected by roll-drift, so that users can quickly and easily assess whether their data needs further attention.