Time: June 26th 2025 | 4:00pm – 5:00pm ET

Dragonfly Evolved: Ultranarrowband Imaging of the Circumgalactic Medium in the Local Universe

Speaker

Deborah Lokhorst | Herzberg Astronomy and Astrophysics

Abstract

The vast majority of baryons in the universe exist outside galaxies, in regions defined as the circumgalactic and intergalactic medium (CGM and IGM). These regions play a critical role in fueling star formation in galaxies but mapping the morphology of the constituent gas to determine the transition of gas into (and out of) galaxies is extremely difficult. We have developed a telescope to directly detect the extremely faint emission from the CGM to enable this mapping ability for local galaxies (z < 0.01). This telescope combines novel ultra-narrow bandpass imaging technology with the Dragonfly Telephoto Array (a mosaic-design telescope composed of Canon telephoto lenses) to enable sensitivity to low surface brightness line emission. A 3-lens prototype of the ultranarrowband upgrade to Dragonfly confirmed this capability and was followed by a 120-lens version (the Dragonfly Spectral Line Mapper), which we used to image H-alpha, [NII] and [OIII] emission in the CGM of local galaxies. We are currently constructing a 1140-lens version of this array, MOTHRA, which will have the sensitivity to fully map the CGM of local galaxies and the potential to detect the filaments of the IGM.

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