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Abstract

Coronal mass ejections (CMEs) that seemingly lack low coronal signatures (LCSs), originally known as “problem storms”, are currently referred to as “stealth” events. They are thought of as lacking a clear LCS such as a flare, jet, prominence eruption, etc. Consequently, recent studies have proposed that “stealth” CMEs form high in the corona, the height and mechanism of which have no clear definition. Our work, which revisited 40 events previously identified as “stealth” events in SOHO/LASCO data, made use of advanced image processing techniques to identify some form of LCSs in SDO/AIA images. The LCSs appear to be flares, filament eruptions, extreme ultraviolet (EUV) waves or jets. Only a few of the 40 CMEs did not have a clear LCS. Our work suggested that the classification of CMEs as “stealth” mostly arises from observational and processing limitations and their actual number, if any, is considerably lower than currently believed. Our current work is focused on revisiting these events using observations from STEREO/SECCHI to provide a multi-point view of the sources of these events. When possible, we make use of COR1 images (and our BFF processing method that suppresses noise in COR1) as a proxy for the observational gap between AIA and LASCO in the first study. Here, we present an overview of “stealth” events, followed by results from our analysis of these events.