Dynamical modelling of the inner Galactic barred disk

2018-05-24T12:03:30Z (GMT) by Portail, Matthieu

Understanding  the  present  state  of  the  Milky  Way  disk  is  a  necessary  first step  towards  learning  about  the  formation  history  of  our  Galaxy.  While  it  is clear from infrared photometry that the inner disk hosts a 5 kpc long bar with a central  Box/Peanut  bulge,  the  interplay  between  the  bar  and  the  inner  disk remains poorly known. To this end we build N-body dynamical models of the inner Galaxy with the Made-to-Measure method, combining deep photometry from the VVV, UKIDSS and 2MASS surveys with kinematics from the BRAVA, OGLE and ARGOS surveys. We explore their stellar to dark matter fraction together  with  their  bar  pattern  speed  and  constrain  from  the  modelling  the effective Galactic potential (gravitational potential + bar pattern speed) inside the solar radius. Our best model is able to reproduce simultaneously (i) the Box/Peanut shape of the bulge, (ii) the transition between bulge and long bar, (iii) the bulge line-of-sight kinematics and proper motion dispersions, (iv) the ARGOS velocity field in the bar region and (v) the rotation curve of the Galaxy inside  10  kpc.  Our  effective  potential  will  be  an  important  input  to  more detailed chemodynamical studies of the stellar populations in the inner Galaxy, as revealed by the ARGOS or APOGEE surveys.

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CC BY 4.0