Precision Calibration via Artificial Light Sources Above the Atmophere

TL;DR

This paper discusses a project to achieve laboratory-level photometric calibration precision for astronomical surveys by using artificial light sources above the atmosphere, applicable across multiple wavelengths.

Contribution

The authors propose and test a novel calibration method using artificial light sources in space and near-field observations to improve photometric accuracy in astronomy.

Findings

Successful testing of a balloon-borne light source.

Implementation of a calibrated laser source in low-Earth orbit.

Potential application to microwave and gravitational wave observations.

Abstract

Deeper understanding of the properties of dark energy via SNIa surveys, and to a large extent other methods as well, will require unprecedented photometric precision. Laboratory and solar photometry and radiometry regularly achieve precisions on the order of parts in ten thousand, but photometric calibration for non-solar astronomy presently remains stuck at the percent or greater level. We discuss our project to erase this discrepancy, and our steps toward achieving laboratory-level photometric precision for surveys late this decade. In particular, we show near-field observations of the balloon-borne light source we are presently testing, in addition to previous work with a calibrated laser source presently in low-Earth orbit. Our technique is additionally applicable to microwave astronomy. Observation of gravitational waves in the polarized CMB will similarly require unprecedented polarimetric and radiometric precision, and we briefly discuss our plans for a calibrated microwave source above the atmosphere as well.