Physics Colloquium: Mapping Ultra Low Surface Brightness Emission Around Nearby Galaxies: The Alliance of UV and Optical Instrumentation

Physics Colloquium
Mapping Ultra Low Surface Brightness Emission Around Nearby Galaxies: The Alliance of UV and Optical Instrumentation

Dr. Nicole Melso
Postdoctoral Fellow
Instrumentation and Technology Development, University of Arizona

Abstract:
All of the undiscovered gas in the universe lies in the dimmest parts of the sky, in the intergalactic medium (IGM) and circumgalactic medium (CGM) beyond galaxies. This gas emits light below the detection threshold of most modern-day observations and is only visible to instruments with extremely low surface brightness sensitivity. This presentation will focus on the development of two instruments optimized to push the boundaries of wide-field, low-surface brightness spectral imaging. Aspera is a UV small satellite mission tailored to map low surface brightness OVI emission in the low-redshift universe. The Circumgalactic Ha Spectrograph (CHaS) is an optical integral field unit (IFU) spectrograph on Kitt Peak designed to detect diffuse ionized gas around nearby galaxies. Both of these spectrographs are powerful survey instruments, leveraging a large light gathering power (grasp) to compete with much larger aperture instruments. The paring of optical and UV instrumentation is key to uncovering the faint reservoir of gas around galaxies and constraining the phase and physical origin of this gas. I will debut the discovery of a new extended emission line region around NGC 1068 discovered with CHaS and highlight future advances in ultra-low surface brightness spectroscopy that will continue to uncover similarly faint, far-flung gas in the local universe.

Bio:
Dr. Nicole Melso is the Alan Brass Prize Postdoctoral Fellow in Instrumentation and Technology Development at the University of Arizona, Steward Observatory. Her research focuses on mapping the properties of diffuse gas around nearby galaxies through ultra-low surface brightness spectral imaging. She is an expert in the development of Optical/UV instrumentation and is currently working on the Aspera UV Small Satellite Mission. She received her PhD from Columbia University, where she worked on the design and commissioning of the Circumgalactic H-alpha Spectrograph (CHaS), an optical IFU spectrograph for MDM Observatory on Kitt Peak.

Intended Audience:
All are Welcome!

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