0 Assigned ID: 172 ----- Attempting Submission 1 (Wed Mar 04 19:08:11 GMT 2020) ----- HST Phase I Proposal 172 successfully submitted. Receipt: # 172-1 ----- Attempting Submission 2 (Fri Mar 06 19:45:11 GMT 2020) ----- HST Phase I Proposal 172 successfully submitted. Receipt: # 172-2 ----- Attempting Submission 3 (Fri Mar 06 21:08:10 GMT 2020) ----- Cepheids are at the nexus of a debate about the possibility that the concordance LCDM model of the Universe is deficient and that new physics is needed to resolve an apparent discrepancy between the local value of H_o and the cosmologically-modeled one. We are proposing to undertake a new and independent determination of H_o using archival imaging of 36 galaxies that contain Cepheids and are hosts to Type Ia supernovae. The Cepheid distance scale is just too imprtant for it not be re-reducded, re-analysed and independently assessed. We have already developed a pipeline that undertakes crowded-field photometry using (DAOPHOT), fine-tuned to the ACS using spatially-variable Tiny Tim PSFs; this will be extended to WFC3 data. Extensive artificial star experiments will be run; and half of our team will undertake the analysis completely blinded, while the other half (without any cross-talk) will run open loop. Both results will be published unchanged. We will make all of the data-reduction and analysis sofware publically available on Github. Intermediate data products will be archived at MAST so that users can re-analyze the data from those intermediate points onwards. Enroute to a new and self-consistent value of the Hubble constant, the other Science Products will be Crowded-field VI photometry, cross-matched for all detected point sources in 36 galaxies. Color-Magnitude diagrams for each of the galaxies. Periods, light curves, mean magnitudes and colors for each of the Cepheids. Period-Luminosity relations and reddening-corrected distances for each of the galaxies. Cepheid-calibrated absolute magnitudes for all Type Ia SNe in Cepheid-host galaxies. Professor Wendy L. Freedman (University of Chicago) and Dr. Barry F. Madore (Carnegie Observatories) share a long-standing mutual interest and applied expertise in determining the expansion rate of the Universe, having pioneered the use of Cepheid variables and the TRGB Method, in the optical and in the near infrared. Both were founding members of the original HST Key Project on the Hubble constant and they have over 100 refereed papers on this topic. Virtually all of the people listed below have been active participants in the Carnegie-Chicago Hubble Constant Program and have years of experience reducing, analyzing and using HST imaging data. Prof. Freedman is the PI and will oversee the program as a whole, hosting weekly telecons and working closely, on all aspects of the program, with each of the postdocs and students, especially those in Chicago. As Co-PI Dr. Madore will also be responsible for guiding the activities of the postdocs and graduate students in Pasadena. Dr. Rachael Beaton is a postdoc at Princeton University, specializing in variable star photometry, and their application to the extragalactic distance scale Dr. Mark Seibert is a free-lance research associate in Pasadena. He and Beaton wrote the existing version of the HST Photometry pipeline Dr. Andy Monson is a research associate at Penn State, operating our robotic telescope in Chile, bringing ground-based data into the calibration. Dr. Jill Neeley is a postdoc at Florida, specializing in variable stars and their application to the extragalactic distance scale. Dr. In-Sung Jang (Leibniz-Institut fur Astrophysik, Potsdam) is a postdoc who has published numerous papers on the TRGB and the Hubble constant using HST data. He will be relocating to Chicago in the fall of this year. Taylor Hoyt and Abigail Lee are graduate students at the University of Chicago, working on the extragalactic distance scale with Professor Freedman. Stellar Populations and the Interstellar Medium Galaxies 0 Regular false false false false false SUPPORTED