• Roman-Duval, Julia Christine
• Cohen, Roger
• Bot, Caroline
• Hirschauer, Alec S.
• Johnson, Lent Clifton
• Sandstrom, Karin Marie
• Yanchulova Merica-Jones, Petia
• Mcquinn, Kristen B. W.
• Murray, Claire E.
• Gordon, Karl D.
• Williams, Benjamin F.
• Choi, Yumi
• Boyer, Martha L.
• Lindberg, Christina Willecke

Abstract

Although galaxies evolve by assembling the interstellar medium (ISM) into stars, standard gas tracers fail to account for the total ISM mass available for star formation. This is especially true at low metallicity and in strong radiation fields where dust shielding and dense molecular gas are scarce. Dust provides an independent tracer across phases, but its basic properties -- mass, grain size and extinction curve -- are poorly constrained between diverse environments. We propose to survey N66, the largest star-forming region in the low-metallicity Small Magellanic Cloud (SMC) with optical and ultraviolet imaging from Wide Field Camera 3. Along with archival imaging in the optical and IR from HST and JWST, we will constrain the intrinsic properties of resolved stars and the intervening dust independently from systematics of IR emission surveys and at 10x higher resolution. We will (1) quantify the influence of ionizing radiation fields on fundamental dust properties (2) map the ISM mass independently of emission systematics to quantify the nature of \`\`dark" gas at low metallicity. HST is the only observatory with the superb resolution and UV sensitivity necessary for these objectives, and N66 is the perfect laboratory for quantifying the influence of star formation activity on the structure of the ISM in the SMC, an excellent prototype for galaxies in the distant Universe....

Topics

• impedance spectroscopy
• grain
• grain size
• phase
• forming