The Dragonfly Spectral Line Mapper is an innovative all-refracting telescope designed to carry out ultra-low surface brightness wide-field mapping of visible wavelength line emission. Equipped with ultranarrowband (0.8 nm bandwidth) filters mounted in Dragonfly Filter-Tilter instrumentation, the Dragonfly Spectral Line Mapper maps Hα, [NII]λ6583, and [OIII]λ5007 line emission produced by structures with sizes ranging from ∼1 to 1000 kpc in the local Universe. These spatial scales encompass that of the exceedingly diffuse and faintly radiating circumgalactic medium, which is singularly difficult to detect with conventional mirror-based telescope instrumentation. Extremely careful control of systematics is required to directly image these large scale structures, necessitating high fidelity sky background subtraction, wavelength calibration, and specialized flat-fielding methods. In this paper, we discuss the on-sky performance of the Dragonfly Spectral Line Mapper with these methods in place.
@article{arxiv.2406.17979,
title = {Realizing the potential of the Dragonfly Spectral Line Mapper: Calibration methods and on-sky performance},
author = {Deborah M. Lokhorst and Seery Chen and Imad Pasha and Victoria Purcell and William P. Bowman and Qing Liu and Zili Shen and Aidan MacNichol and Evgeni I. Malakhov and Roberto G. Abraham and Pieter van Dokkum},
journal= {arXiv preprint arXiv:2406.17979},
year = {2024}
}