Precise Astronomical Flux Calibration and its Impact on Studying the Nature of Dark Energy

TL;DR

Achieving 1% flux calibration precision is crucial for advancing dark energy research through supernova observations, requiring improvements in calibration techniques and atmospheric monitoring.

Contribution

The paper identifies key sources of systematic errors in flux calibration and discusses strategies to reach 1% accuracy using celestial standards and advanced calibration methods.

Findings

Systematic uncertainties in flux calibration dominate error budgets.

Current efforts aim to achieve 1% calibration accuracy.

Improved calibration techniques can refine dark energy constraints.

Abstract

Measurements of the luminosity of type Ia supernovae vs. redshift provided the original evidence for the accelerating expansion of the Universe and the existence of dark energy. Despite substantial improvements in survey methodology, systematic uncertainty in flux calibration dominates the error budget for this technique, exceeding both statistics and other systematic uncertainties. Consequently, any further collection of type Ia supernova data will fail to refine the constraints on the nature of dark energy unless we also improve the state of the art in astronomical flux calibration to the order of 1%. We describe how these systematic errors arise from calibration of instrumental sensitivity, atmospheric transmission, and Galactic extinction, and discuss ongoing efforts to meet the 1% precision challenge using white dwarf stars as celestial standards, exquisitely calibrated detectors as fundamental metrologic standards, and real-time atmospheric monitoring.