0 Assigned ID: 711 ----- Attempting Submission 1 (Fri Apr 10 19:35:06 GMT 2015) ----- HST Phase I Proposal 711 (ArchivalPGCC.apt) successfully submitted. Receipt: # 711-1 ----- Attempting Submission 2 (Fri Apr 10 20:18:00 GMT 2015) ----- HST Phase I Proposal 711 (ArchivalPGCC.apt) successfully submitted. Receipt: # 711-2 ----- Attempting Submission 3 (Fri Apr 10 20:21:27 GMT 2015) ----- The recent release of the Planck Catalogue of Galactic Cold Clumps (PGCC) has provided a wealth of information about the cold dust content of the ISM across the entire sky. The purpose of the PGCC is to eventually yield insight into the processes by which interstellar material progresses from the diffuse ISM to molecular clouds to stars. By combining the data from Planck with the diagnostic capabilities of UV absorption line spectroscopy, we aim to better characterize the physical conditions of the interstellar gas within these cold clouds. To our knowledge, there have been no studies using HST to investigate the properties of the gas within the cold dust clouds discovered by Planck. We have identified 35 sightlines containing 165 datasets within the HST STIS archive that fall near one or more of these PGCC clouds. We propose to analyze the corresponding interstellar absorption lines contained within these datasets to study a variety of important cloud properties. Our goals in this archival study are to investigate the gas thermal pressure using C I fine-structure excitation, and look for evidence of shock processing in the dust by determining the abundance ratio between depleted and undepleted elements. Additionally, we plan to measure the isotopic abundance ratio of CO in the clouds and investigate if high pressures are affecting their chemical processes. ISM AND CIRCUMSTELLAR MATTER 0 Regular false false false false false SUPPORTED