Flare Induced Sunquake Signatures in the Ultraviolet as Observed by the Atmospheric Imaging Assembly

TL;DR

This study demonstrates that flare-induced sunquake signatures can be detected in ultraviolet wavelengths, specifically in the SDO/AIA 1600 Å and 1700 Å passbands, indicating their presence in the lower chromosphere.

Contribution

It is the first to analyze UV signatures of sunquakes using SDO/AIA data, revealing their detectability and characteristics in the lower chromosphere.

Findings

9 out of 62 sunquakes showed clear UV signatures

Maximum apparent velocities of 41 km/s observed in UV data

No correlation between flare class and UV sunquake detection

Abstract

Sunquakes (SQs) have been routinely observed in the solar photosphere, but it is only recently that signatures of these events have been detected in the chromosphere. We investigate whether signatures of SQs are common in Ultraviolet (UV) continua, which sample the solar plasma several hundred km above where SQs are typically detected. We analyse observations from the Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA) 1600 {\AA} and 1700 {\AA} passbands, for SQ signatures induced by the flares of Solar Cycle 24. We base our analysis on the 62 SQs detected in the recent statistical study presented by Sharykin & Zosovichev (2020). We find that 9 out of 62 SQ candidates produced a response that is clearly detected in running difference images from the AIA 1600 {\AA} and 1700 {\AA} channels. A binary frequency filter with a width of 2 mHz, centred on 6 mHz, was applied to the data. The first signature of each SQ was detected at distances between 5.2 Mm to 25.7 Mm from the associated flare ribbon. Time-distance and regression analysis allowed us to calculate the apparent transverse velocities of the SQs in the UV datasets and found maximum velocities as high as 41 km s-1, 87 Mm away from the SQ source. Our analysis shows that flare induced SQ signatures can be detected in the SDO/AIA 1600 {\AA} and 1700 {\AA} passbands, hinting at their presence in the lower chromosphere. There was no apparent correlation between GOES flare classification, and the appearance of the SQ at these heights.