The EXTraS project: Exploring the X-ray Transient and variable Sky

Vol. 650
15. Numerical methods and codes

The EXTraS project: Exploring the X-ray Transient and variable Sky

Everything flows. Time is a fundamental perception in our life. In this paper, De Luca and collaborators investigate the timing properties of ~400,000 X-ray sources found in the XMM-Newton database for over 10 years of observations. They characterize periodic and aperiodic (either short- and long-term) variability, spanning more than eight orders of magnitude in time and six orders of magnitude in flux. They also searched for new transient events that are too faint to be detected as sources in the overall images. This investigation provides a thorough characterization of variability in its entire aspect and a legacy for future studies. The Exploring the X-ray Transient and variable Sky (EXTraS) project was funded by the European Union and all the results and methods are publicly available at the project website.