Automatic detection of Ellerman bombs in the H$\alpha$ line

TL;DR

This paper presents an automated method for detecting and analyzing Ellerman bombs in high-resolution solar H-alpha data, providing statistical insights into their properties and occurrence.

Contribution

The authors developed a novel automated detection pipeline using a star-finding algorithm to identify and track EBs, distinguishing them from pseudo-EBs in solar observations.

Findings

Detected 2257 EBs across datasets with an average area of 0.44 arcsec².

Median EB lifetime was found to be 2.3 minutes.

Average contrast of detected EBs was 1.4 times the quiet Sun intensity.

Abstract

Ellerman bombs (EBs) are small and short-lived magnetic reconnection events in the lower solar atmosphere, most commonly reported in the line wings of the H$\alpha$ line. These events are thought to play a role in heating the solar chromosphere and corona, but their size, short lifetime, and similarity to other brightenings make them difficult to detect. We aim to automatically detect and statistically analyze EBs at different heliocentric angles to find trends in their physical properties. We developed an automated EB detection pipeline based on a star-finding algorithm. This pipeline was used on ten high-resolution H$\alpha$ datasets from the 1-meter Swedish Solar Telescope (SST). This pipeline identifies and tracks EBs in time, while separating them from visually similar pseudo-EBs. It returns key parameters such as size, contrast, lifetime, and occurrence rates based on a dynamic threshold and the more classical static `contrast threshold` of 1.5 times the mean quiet-Sun (QS) intensity. For our dynamic threshold, we found a total of 2257 EBs from 28,772 individual detections across our datasets. On average, the full detection set exhibits an area of 0.44 arcsec$^2$ (0.37 Mm$^2$), a peak intensity contrast of 1.4 relative to the QS, and a median lifetime of 2.3 min. ...