LOFT - a Large Observatory For x-ray Timing

TL;DR

LOFT is a proposed large-area X-ray observatory utilizing silicon drift detectors to enable high time resolution observations, aiming to advance fundamental physics studies such as black hole characterization and dense matter equations of state.

Contribution

The paper presents a realistic concept for a large-area X-ray timing mission using silicon drift detectors, achieving effective areas of 10-15 m² with modest resources.

Findings

Silicon drift detectors offer high time and energy resolution at room temperature.

A feasible mission concept with 10-15 m² effective area using small-medium class spacecraft.

Potential to significantly improve X-ray timing observations for fundamental physics.

Abstract

The high time resolution observations of the X-ray sky hold the key to a number of diagnostics of fundamental physics, some of which are unaccessible to other types of investigations, such as those based on imaging and spectroscopy. Revealing strong gravitational field effects, measuring the mass and spin of black holes and the equation of state of ultradense matter are among the goals of such observations. At present prospects for future, non-focused X-ray timing experiments following the exciting age of RXTE/PCA are uncertain. Technological limitations are unavoidably faced in the conception and development of experiments with effective area of several square meters, as needed in order to meet the scientific requirements. We are developing large-area monolithic Silicon Drift Detectors offering high time and energy resolution at room temperature, which require modest resources and operation complexity (e.g., read-out) per unit area. Based on the properties of the detector and read-out electronics that we measured in the lab, we developed a realistic concept for a very large effective area mission devoted to X-ray timing in the 2-30 keV energy range. We show that effective areas in the range of 10-15 square meters are within reach, by using a conventional spacecraft platform and launcher of the small-medium class.