{
  "id": "1910.02297",
  "version": "v1",
  "published": "2019-10-05T17:14:44.000Z",
  "updated": "2019-10-05T17:14:44.000Z",
  "title": "Comparing Observed Stellar Kinematics and Surface Densities in a Low Latitude Bulge Field to Galactic Population Synthesis Models",
  "authors": [
    "Sean K. Terry",
    "Richard K. Barry",
    "David P. Bennett",
    "Aparna Bhattacharya",
    "Jay Anderson",
    "Matthew T. Penny"
  ],
  "comment": "17 pages, 10 figures. Submitted to ApJ",
  "categories": [
    "astro-ph.SR",
    "astro-ph.EP",
    "astro-ph.GA"
  ],
  "abstract": "We present an analysis of Galactic bulge stars from Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) observations of the Stanek window (l,b=[0.25,-2.15]) from two epochs approximately two years apart. This dataset is adjacent to the provisional Wide-field Infrared Survey Telescope (WFIRST) microlensing field. Proper motions are measured for approximately 115,000 stars down to 28th mag in V band and 25th mag in I band, with accuracies of 0.5 mas yr$^{-1}$ (20 km s$^{-1}$) at I $\\approx$ 21. A cut on the longitudinal proper motion $\\mu_l$ allows us to separate disk and bulge populations and produce bulge-only star counts that are corrected for photometric completeness and efficiency of the proper-motion cut. The kinematic dispersions and surface density in the field are compared to the nearby SWEEPS sight-line, finding a marginally larger than expected gradient in stellar density. The observed bulge star counts and kinematics are further compared to the Besan\\c{c}on, Galaxia, and GalMod Galactic population synthesis models. We find that most of the models underpredict low-mass bulge stars by $\\sim$33% below the main-sequence turnoff, and upwards of $\\sim$70% at redder J and H wavebands. While considering inaccuracies in the Galactic models, we give implications for the exoplanet yield from the WFIRST microlensing mission.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-10-05T17:14:44.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "galactic population synthesis models",
      "low latitude bulge field",
      "surface density",
      "stellar kinematics",
      "underpredict low-mass bulge stars"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}