Around Gaia Alerts in 20 questions

TL;DR

This paper discusses the Gaia space mission's capabilities and challenges in detecting and classifying transient astronomical phenomena using its comprehensive astrometric and photometric data over a five-year period.

Contribution

It provides an overview of the Gaia mission's objectives, data collection methods, and the specific challenges faced by the Photometric Science Alerts team in early detection and classification of transient events.

Findings

Gaia will observe the entire sky for 5 years, enabling discovery of numerous transient events.

Challenges include real-time detection, classification, and prompt alert dissemination.

The paper outlines strategies to address these challenges in Gaia's transient detection efforts.

Abstract

Gaia is a European Space Agency (ESA) astrometry space mission, and a successor to the ESA Hipparcos mission. Gaia's main goal is to collect high-precision astrometric data (i.e. positions, parallaxes, and proper motions) for the brightest 1 billion objects in the sky. These data, complemented with multi-band, multi-epoch photometric and spectroscopic data collected from the same observing platform, will allow astronomers to reconstruct the formation history, structure, and evolution of the Galaxy. Gaia will observe the whole sky for 5 years, providing a unique opportunity for the discovery of large numbers of transient and anomalous events, e.g. supernovae, novae and microlensing events, GRB afterglows, fallback supernovae, and other theoretical or unexpected phenomena. The Photometric Science Alerts team has been tasked with the early detection, classification and prompt release of anomalous sources in the Gaia data stream. In this paper, we discuss the challenges we face in preparing to use Gaia to search for transient phenomena at optical wavelengths.