A Lifetime of Influence: Abstracts, Talks, and Posters
 

A New Study of the LMC's Kinematics

Knut Olsen (NOAO)

Robert Blum (NOAO)

Karl Gordon (STScI)

Jason Harris (NOAO)

Phil Massey (Lowell Observatory

Margaret Meixner (STScI)

Sally Oey (University of Michigan)

Schuyler Van Dyk (Spitzer Science Center)

Dennis Zaritsky (University of Arizona)

In a recent analysis of previously published data on the H I gas, carbon stars, and red supergiant stars of the Large Magellanic Cloud, we found striking new evidence of the effect of the LMC's ongoing interactions with the Small Magellanic Cloud and Milky Way. First, ~10% of the 857 carbon stars studied were found to be associated with tidal HI streamers, the first instance in which tidally drawn out stars have been identified in the LMC. Second, we found rotation curve amplitudes ranging from 61 km s-1 for the carbon stars to 107 km s-1 for the 168 red supergiants, casting new doubt on previous estimates of the LMC's total mass based on the carbon stars. Finally, from the velocity and spatial distributions of the HI and the red supergiants, we found that the LMC’s disk is significantly lopsided, thus requiring that its populations lie on predominantly eliptical orbits, not circular ones as is generally assumed. In order to investigate the questions raised by these findings, we have collected high quality spectra of 5292 stars in the direction of the LMC, including 481 LMC red supergiants and 1950 carbon stars. Based on these spectra, we will present a new analysis of the LMC's internal kinematics.