Andrew Saydjari (NMSU)

The shadow of interstellar dust looms large in observational astronomy, but the signatures it imprints on starlight can be leveraged to reveal the structure of our Galaxy. The dust extinction curve is complex and exhibits features across a wide range of wavelength scales, from relatively narrow diffuse interstellar bands (“DIBs”) to the overall slope of the optical extinction curve. In this talk, I will discuss a new generation of 3+1D (x, y, z, v) dust maps unlocked by large spectroscopic surveys that reveal not only where the dust is, but also how it is moving. Then, I will show how a detailed analysis of the line shape of DIBs with respect to changes in the slope of the dust extinction curve can constrain the geometric and physical properties of the carriers of two DIBs using SDSS/APOGEE spectra, including their masses to better than 10%. Finally, I will demonstrate that careful forward modeling of SPHEREx observations enables high resolution (6”) all-sky PAH maps, including precision measurements of the 3.4/3.3 micron PAH ratio. Similar techniques will be essential to plan and enable PRIMA(ll), a revolutionary FIR all-sky GO survey with PRIMA.