Nicole Melso

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 including: the fuel for future star formation, the remnants of past galaxy mergers, and the large-scale structure of the universe. I will debut the discovery of a new extended emission line region around NGC 1068 and highlight advances in ultra-low surface brightness spectroscopy – including the development of future instruments for SOAR – that will continue to uncover similarly faint, far-flung gas in the local universe.