0 Assigned ID: 3403 ----- Attempting Submission 1 (Fri Mar 25 18:40:45 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-1 ----- Attempting Submission 2 (Fri Mar 25 20:52:05 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-2 ----- Attempting Submission 3 (Fri Mar 25 20:53:52 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-3 ----- Attempting Submission 4 (Fri Mar 25 21:30:13 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-4 ----- Attempting Submission 5 (Fri Mar 25 23:33:18 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-5 ----- Attempting Submission 6 (Fri Mar 25 23:39:08 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-6 ----- Attempting Submission 7 (Fri Mar 25 23:46:21 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-7 ----- Attempting Submission 8 (Fri Mar 25 23:55:00 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-8 ----- Attempting Submission 9 (Mon Mar 28 15:51:46 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-9 ----- Attempting Submission 10 (Mon Mar 28 15:55:09 GMT 2022) ----- HST Phase I Proposal 3403 successfully submitted. Receipt: # 3403-10 ----- Attempting Submission 11 (Mon Mar 28 16:04:27 GMT 2022) ----- Over the past decade, high-resolution large-area FIR-submm surveys have revealed a previously-overlooked class of nearby galaxies with bizarre ISM properties: Blue And Dusty Gas-Rich sources - 'BADGRs'. BADGRs are very blue flocculent/irregular galaxies, typically containing a greater mass of HI than stars, and are the most dust-rich galaxies in the modern Universe, with M_d/M_s > 10^-2.75. But despite this dust richness, the fraction of their UV photons that is absorbed by dust is 5-20 times less than in normal late-type galaxies (traced by BADGRs' exceptionally low IRX ratios). Furthermore, BADGRs are very poor in molecular gas, despite having high specific star formation rates; and have unusually cold dust, despite intense UV radiation fields. Existing data are unable to explain the multiple paradoxes presented by BADGRs. High-resolution star-by-star extinction mapping is the tool we need to untangle their mysteries. There are two BADGRs, NGC4449 & NGC7793, that are close enough, and have the required archival HST data, to enable this. We will use these data to fit the multi- wavelength SEDs of the stars in these BADGRs, modelling the dust along the line-of-sight to each. With the resulting high-resolution extinction maps we will: compare the detailed dust geometry to the UV radiation field; relate dust temperatures to the energy balance between extinction & emission; determine if dust mass opacity in BADGRs is different from normal galaxies; test if the lack of molecular gas is due to CO freeze-out in opaque dust clouds; and quantify the molecular star forming efficiency in different regions, by comparing our maps of extinction & young stars to public ALMA CO data. The PI, Christopher Clark, is an expert in studying the resolved properties of the ISM in the local Universe, especially dust, through multiwavelength tracers. His publications feature work on mapping the variation in dust properties within nearby galaxies, on how ISM characteristics differ in local galaxies at different evolutionary stages, and on producing multiwavelength pipelines to process and analyze observations of nearby galaxies. He has lead and co-authored papers specifically exploring the unusual characteristics of BADGRs. The team's co-investigators include specialists in exploiting resolved stellar population studies of nearby galaxies (Y. Choi, K. Gordon, B. Williams, P Yanchulova Merica-Jones), many of whom have been leaders in prominent HST programs in the field, such as PHAT (PID 12055), LUVIT (PID 15275), Scylla (PID 15891), METAL (PID 14675), and SMIDGE (PID 13659). Team members C. Clark, K. Gordon, H. Gomez, and J. Roman-Duval have all published studies on the origins of dust and its evolution in the ISM. Team members C. Clark, H. Gomez, J Roman-Duval, and K. Gordon are experts in modelling FIR-submm dust emission. Team members J. Roman-Duval and M. Decleir have a particular background in using UV observations to understand the dust and ISM properties of local galaxies. Team members C. Clark. and H. Gomez have authored works exploring the unusual properties of BADGRs. Also, many of the team are contributors to the BEAST software which will be central to our analysis (C. Choi, C. Clark, K. Gordon, C. Murray, B. Williams, P. Yanchulova Merica-Jones). Galaxies Stellar Populations and the Interstellar Medium 0 Regular false false true false false false SUPPORTED