Abstract

A Study of the Sagittarius Tidal Stream Using Maximum Likelihood

Nathan Cole (Rensselaer Polytechnic Institute)

Heidi Jo Newberg (Rensselaer Polytechnic Institute), Malik Magdon-Ismail (Rensselaer Polytechnic Institute), Travis Desell (Rensselaer Polytechnic Institute), Carlos Varela (Rensselaer Polytechnic Institute), Boleslaw Szymanski (Rensselaer Polytechni

We present results of maximum likelihood fits to the Sgr dwarf tidal stream in the Milky Way. The spheroid flattening and core radius are also explored. The maximum likelihood method for determining the spatial properties of tidal debris and of the Galactic stellar spheroid has proven to be an effective means for studying tidal disruption, allowing us to construct full visualizations of the paths of the stellar streams. This has become ever more important as new debris is being found at an increasing rate due to the amount of data brought to us by large surveys. This debris needs to be characterized and studied: for its own values as well as the need to know all the debris that exists in order to study the spheroid itself. Our maximum likelihood method models the tidal debris and the spheroid: over small spatial extent, the tidal debris is modeled as a cylinder having density that falls off from the axis as a Gaussian; the spheroid is modeled as a Hernquist profile. Extensions to this algorithm that allow for the study of more complex data sets (the removal of bad data and the existence of multiple debris pieces within a single data set) have been made. We are continuing a systematic study of the SDSS data in an effort to characterize all Sagittarius debris within the survey.

Mode of presentation: poster