Major Flare Watch Evaluation

Introduction

The major flares that produce gamma-ray lines are the highest priority target of the RHESSI Mission. Multi-wavelength imaging and spectroscopic observations before, during and after such flares are crucial to their interpretation. To optimize such observations, the Max Millennium Chief Observers (MM_COs) [1] announce a Major Flare Watch when the probability of gamma-ray-producing flares is high. These announcements appear in the Max Millennium Messages of the Day [2], distributed to a self-identifying list of over 200 observers and mission planners through the MMmmotd mailing list and archive [3].

Throughout the RHESSI mission, up to now, the MMCOs have used a set of Major Flare Watch criteria [4] that are an outgrowth of the classic BEARALERTS - A Successful Flare Prediction System" [5] paper by Zirin and Marquette. A typical MFW announcement [6] identifies the coordinates of a region likely to produce a major flare, and provides some rationale for the choice. How well has this system worked? Read on ...