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OBTAINING OBSERVATIONS AS A SECONDARY SCIENCE GOAL OF THE GRB MISSION SWIFT THE 30CM UVOT CAMERA HAS DISCOVERED A BI-MODALITY IN NUV-OPTICAL EMISSION FROM FAST-DECLINING TYPE IA SUPERNOVAE (SNE~IA). ONE GROUP APPEARS TO BE A FAST-DECLINING EXTENSION OF NORMAL SNE~IA (WE CALL THESE NARROW-NORMALS) WHILE THE OTHER APPEARS AS DISTINCT GROUP FAINT (ALSO LABELLED AS COOL OR 91BG-LIKE). AS SNE~IA ARE USED AS COSMOLOGICAL DISTANCE INDICATORS IT IS IMPORTANT TO ADDRESS ALL VARIATIONS WITHIN THE CLASS. THIS IS IMPORTANT THEORETICALLY TO UNDERSTAND THE PHYSICAL DIFFERENCES THAT LEAD TO THE VARIATIONS AS WELL AS COSMOLOGICALLY TO ASSESS WHETHER NARROW-NORMALS MIGHT BE INCLUDED IN THE COSMOLOGICAL DISTANCE SAMPLE. THIS PROPOSAL SEEKS SUPPORT BOTH TO DRAMATICALLY INCREASE THE UVOT SAMPLE OF NARROW-NORMAL AND FAINT SNE BEYOND THE SAMPLE IN MILNE ET AL. 2010 (FROM 5 TO 40 SNE) AND TO ENHANCE THE SAMPLE WITH OBSERVATIONS MADE IN OTHER WAVELENGTHS TO BETTER UNDERSTAND THE DIFFERENCES IN THE SN EMISSION THE EXPLOSION PHYSICS AND EXPLOSION PROGENITORS. FOR COSMOLOGY WE WILL DETERMINE THE ABSOLUTE MAGNITUDES OF THE SNE IN THE UVOT SAMPLE UTILIZING EXISTING CEPHEID OR SBF DISTANCES FOR VERY NEARBY SNE AND UTILIZING HUBBLE FLOW DISTANCES FOR SLIGHTLY FURTHER SNE. THIS STUDY WILL DETERMINE WHETHER THE NARROW-NORMALS ARE CONSISTENT WITH AN EXTRAPOLATION OF THE EXISTING LUMINOSITY-WIDTH RELATION (LWR). FOR THE FAINT SAMPLE THE QUESTION WILL BE WHETHER THEY FOLLOW A LWR WITH A DIFFERENT SLOPE THAN THE NORMALS OR INSTEAD EXHIBIT NO CORRELATION BETWEEN PEAK WIDTH AND LUMINOSITY BUT RATHER SCATTER ABOUT A FAINTER MEAN ABSOLUTE MAGNITUDE. TOWARDS THE THEORETICAL UNDERSTANDING OF THE BI-MODALITY IN FAST-DECLINING SNE~IA WE WILL DELVE FURTHER INTO THE EMERGING CORRELATIONS PRESENT IN THE INITIAL SAMPLE. AS THE UV EMISSION IS A SENSITIVE PROBE OF THE DISTRIBUTION OF IRON-PEAK ELEMENTS IN THE SN EJECTA THE UVOT LIGHT CURVES ARE REVEALING THE NATURE OF THE EXPLOSIVE NUCLEOSYNTHESIS IN THE SN EXPLOSION. THIS IS IMPORTANT AS THE GREATEST MYSTERY OF SNE~IA; "WHAT IS THE PROGENITOR SYSTEM THAT LEADS TO A SNIA?" REMAINS PARTIALLY UNANSWERED. INDEED IT IS A QUESTION WHETHER THERE IS A SINGLE CHANNEL TO A SN~IA OR INSTEAD A NUMBER OF CHANNELS. INCLUDED IN THIS INVESTIGATION WILL BE STUDYING THE HOST GALAXIES OF EACH SUB-CLASS AS IT HAS ALREADY BEEN SHOWN THAT FAST-DECLINING SNE ARE MORE COMMON IN (E/S0) GALAXIES THAN NORMAL SNE~IA. WE WILL EXPLORE THIS AS A FUNCTION OF FAST-DECLINING SUBCLASS AND THEN EXTEND THE WORK TO EXACT LOCATION OF THE SN WITHIN THE HOST GALAXY. THE THEORETICAL WORK WILL ADVANCE THROUGH MORE SNE INCLUDED IN THE INVESTIGATION BUT ALSO BECAUSE MORE INFORMATION WILL BE INCLUDED FOR EACH SN. COLLECTIVELY THESE EFFORTS WILL MAXIMIZE THE SCIENTIFIC RETURN FROM THE VERY SUCCESSFUL NASA SWIFT MISSION. THIRTEEN YEARS OF OBSERVATIONS AND EFFORT HAVE AFFORDED INSIGHT INTO THE CAPABILITIES OF THE UVOT FOR SN~IA SCIENCE THREE MORE YEARS OF CONCENTRATED EFFORT WILL PRODUCE BREAKTHROUGHS IN THE STUDY OF SNEIA AS WELL AS PROVIDE IMPORTANT SUPPORT FOR FUTURE HIGH-Z SN SEARCHES.

$277,639FY2020National Aeronautics and Space AdministrationNASA

University Of Arizona, Tucson AZ

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