Introduction: In this report, we present the latest spectroscopic observations of the recently discovered stellar overdensity near the northern edge of the Small Magellanic Cloud (SMCNOD), taken as part of the Southern Stellar Stream Spectroscopic Survey (S5). A full kinematic analysis, including Gaia DR3 proper motions, was conducted. We model the candidate members of SMCNOD with a mixture model (stellar overdensity and MW background) in kinematics, metallicity, and proper motion space. The method does not require prior knowledge of stellar overdensity membership. This is the first study of accurate kinematics of SMCNOD, and our obtained metallicity is in agreement with the median metallicity of the nearby old SMC population. Further, we investigated the origin of SMCNOD with variable stars from the fourth release of the Optical Gravitational Lensing Experiment (OGLE), and analyzed the potential association of Eclipsing Binaries, Anomalous Cepheids, RR Lyrae stars, and Classical Cepheids with the stellar overdensity using their spatial distribution.
The content of this repository may be updated to be more complete.
The folder PM_compare would include my up-to-date analysis on adding the proper motions to our model for SMCNOD, how it differs from a model without proper motions, a model with pmra and pmdec modeled as 1-D respectively, and a model with 2-D proper motions considering covariance matrix.
We update the folder PM_compare to also include different background checks, uniform and normal distribution