ULTRAVIOLET PROPERTIES OF STELLAR POPULATIONS ON THE LARGE MAGELLANIC CLOUD

  • Siegel, Michael M. (PI)

Project: Research project

Project Details

Description

THE LARGE MAGELLANIC CLOUD (LMC) IS A KEYSTONE FOR STUDYING STAR FORMATION AND EVOLUTION IN THE LOCAL GROUP. IT IS HOST TO THOUSANDS OF HOT YOUNG STARS AND REGIONS OF INTENSE STAR FORMATION ACTIVITY. UNLIKE OTHER STAR-FORMING GALAXIES HOWEVER THE LMC IS RELATIVELY CLOSE (50 KPC) WHICH ALLOWS FOR IN-DEPTH STUDY OF RESOLVED STELLAR POPULATIONS AND STAR-FORMING REGIONS OVER A BROAD RANGE OF AGES METALLICITIES AND FOREGROUND REDDENINGS. WE HAVE RECENTLY COMPLETELY SUCCESSFUL PANCHROMATIC STUDIES OF THE SMALL MAGELLANIC CLOUD (SMC) M31 AND M33 USING ARCHIVAL MULTI-FILTER NEAR-ULTRAVIOLET (NUV) IMAGING FROM THE SWIFT UV/OPTICAL TELESCOPE (UVOT) IN COMBINATION WITH GROUND- AND SPACE-BASED OPTICAL/INFRARED DATA (OIR) INCLUDING DATA FROM THE SPITZER MISSION AND THE TWO MICRON ALL SKY SURVEY (2MASS). THESE SURVEYS MEASURED FINELY-RESOLVED STAR-FORMATION HISTORIES PROVIDED INSIGHTS INTO STELLAR EVOLUTION AND PRODUCED EVIDENCE THAT THE REDDENING LAW VARIES OVER THE SURFACE OF LOCAL GROUP GALAXIES. THEY WERE ABLE TO PROBE THESE ISSUES IN MORE DETAIL THAN PREVIOUS SURVEYS DUE TO THE MULTI-FILTER UVOT PHOTOMETRY WHICH NOT ONLY UTILIZES A WAVELENGTH RANGE MORE SENSITIVE TO THE PROPERTIES OF HOT STARS AND YOUNG STELLAR POPULATIONS BUT INCLUDES FILTERS THAT COVER THE 2175 ANGSTROM BUMP IN THE UV EXTINCTION CURVE. WE NOW PROPOSE TO APPLY THESE TECHNIQUES TO THE LARGE MAGELLANIC CLOUD (LMC) WHICH HAS AN IDENTICAL DATA SET. WE PLAN TO INVESTIGATE SEVERAL OUTSTANDING ASTROPHYSICAL QUESTIONS: 1) INVESTIGATE THE NUV PROPERTIES OF STAR FORMING REGIONS IN THE LMC AND THE RELATIONSHIPS BETWEEN STAR FORMATION RATE INDICATORS IN THE HETEROGENEOUS ENVIRONMENT OF THE LMC; 2) WE WILL CONTRAST THAT AGAINST OUR SURVEYS OF THE LOW-METALLICITY SMC AND THE MORE DISTANT GALAXIES M~31 AND M~33; 3) IDENTIFY AND CHARACTERIZE UV-BRIGHT STARS SUCH AS POST-ASYMPTOTIC GIANT BRANCH STARS PROVIDING INPUT INTO SPECTRAL SYNTHESIS MODELS OF EXTRAGALACTIC OBJECTS. USE PANCHROMATIC POINT-SOURCE PHOTOMETRY TO DERIVE TEMPERATURES ABUNDANCES AND FOREGROUND REDDENINGS FOR INDIVIDUAL STARS TO PROBE FINE DETAILS OF THE LMC'S STELLAR POPULATIONS; 4) USE UVOT COLOR-MAGNITUDE DIAGRAMS PHOTOMETRY OF STAR-FORMING REGIONS AND MEASURES OF INTEGRATED LIGHT TO TRACE THE RECENT STAR FORMATION HISTORY OF THE LMC; 5) USE UVOT COLOR-MAGNITUDE DIAGRAMS PHOTOMETRY OF STAR-FORMING REGIONS AND MEASURES OF INTEGRATED LIGHT TO MEASURE THE UV DUST EXTINCTION CURVE ACROSS THE BAR OF THE LMC AND SEARCH FOR INSIGHTS INTO THE PHYSICAL CAUSE OF THE 2175 ANGSTROM BUMP. THE UNIQUE CONTRIBUTION OF THIS PROPOSAL WILL BE THE BROAD MULTI-WAVELENGTH STUDY OF THE MOST ACTIVE STAR-FORMING GALAXY IN THE LOCAL GROUP PUSHING OUR UNDERSTANDING INTO A DOMAIN NOT EXPLORED WITH THE SMC M31 OR M33.
StatusFinished
Effective start/end date2/25/192/24/22

Funding

  • NASA Headquarters

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