Milky Way Tomography with K and M Dwarf Stars: the Vertical Structure of the Galactic Disk

Abstract

We use the number density distributions of K and M dwarf stars with vertical height from the Galactic disk, determined using observations from the Sloan Digital Sky Survey, to probe the structure of the Milky Way disk across the survey's footprint. Using photometric parallax as a distance estimator we analyze a sample of several million disk stars in matching footprints above and below the Galactic plane, and we determine the location and extent of vertical asymmetries in the number counts in a variety of thin- and thick-disk subsamples in regions of some 200 square degrees within 2 kpc in vertical distance from the Galactic disk. These disk asymmetries present wave-like features as previously observed on other scales and at other distances from the Sun. We additionally explore the scale height of the disk and the implied offset of the Sun from the Galactic plane at different locations, noting that the scale height of the disk can differ significantly when measured using stars only above or only below the plane. Moreover, we compare the shape of the number density distribution in the north for different latitude ranges with a fixed range in longitude and find the shape to be sensitive to the selected latitude window. We explain why this may be indicative of a change in stellar populations in the latitude regions compared, possibly allowing access to the systematic metallicity difference between thin- and thick-disk populations through photometry.

41 pages, 17 figures, accepted for publication in ApJ; published version [oversight in Fig. 12 fixed]

References in corpus (29)

• The Gaia mission
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Cats and Dogs, Hair and A Hero: A Quintet of New Milky Way Companions
• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• The Local Dark Matter Density
• Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function
• The observed spiral structure of the Milky Way
• Kinematic Distances to Molecular Clouds identified in the Galactic Ring Survey
• Rings and Radial Waves in the Disk of the Milky Way
• The Spiral Structure of the Outer Milky Way in Hydrogen
• The Invisibles: A Detection Algorithm to Trace the Faintest Milky Way Satellites
• Constraining the thick disc formation scenario of the Milky Way
• Transient spirals as superposed instabilities
• Bending and Breathing Modes of the Galactic Disk
• Radial and vertical flows induced by galactic spiral arms: likely contributors to our "wobbly Galaxy''
• A Map of Dust Reddening to 4.5 kpc from Pan-STARRS1
• Galactic Warps Induced By Cosmic Infall
• Dynamics of the Magellanic Clouds in a LCDM Universe
• The origin of large peculiar motions of star-forming regions and spiral structures of our Galaxy
• Displacement of the Sun from the Galactic Plane
• The morphology of the Milky Way - I. Reconstructing CO maps from simulations in fixed potentials
• The Vertical Structure and Kinematics of Grand Design Spirals
• The vertical effects of disc non-axisymmetries from perturbation theory: the case of the Galactic bar
• Tracing the Galactic spiral structure with embedded clusters
• Galactoseismology and the Local Density of Dark Matter
• New Galactic embedded clusters and candidates from a WISE Survey
• Discovery of two embedded clusters with WISE in the high Galactic latitude cloud HRK 81.4-77.8
• New detections of embedded clusters in the Galactic halo

Cited by in corpus (22)

• CARMENES input catalogue of M dwarfs V. Luminosities, colours, and spectral energy distributions
• The Gaia-ESO Survey: Carbon abundance in the Galactic thin and thick disks
• The Extinction and Distance of the MBM Molecular Clouds at High Galactic Latitude
• Can ultralight dark matter explain the age-velocity dispersion relation of the Milky Way disc: A revised and improved treatment
• The Milky Way, Coming into Focus: Precision Astrometry Probes its Evolution, and its Dark Matter
• The Panchromatic Hubble Andromeda Treasury XX: The Disk of M31 is Thick
• Photometric Calibrations of M-dwarf Metallicity with Markov Chain Monte Carlo and Bayesian Inference
• Applying Noether's theorem to matter in the Milky Way: evidence for external perturbations and non-steady-state effects from Gaia Data Release 2
• A homogeneous sample of 34 000 M7-M9.5 dwarfs brighter than $J$=17.5 with accurate spectral types
• The Outer spiral arm of the Milky Way using Red Clump stars
• Probing Axial Symmetry Breaking in the Galaxy with Gaia Data Release 2
• Vertical stellar density distribution in a non-isothermal galactic disc
• A method to calculate the local density distribution of the Galaxy from the Tycho-Gaia Astrometric Solution data
• Axial Asymmetry Studies in Gaia Data Release 2 Yield the Pattern Speed of the Galactic Bar
• Two-point correlation function studies for the Milky Way: discovery of spatial clustering from disk excitations and substructure
• Detailed Mapping of the Galactic Disk Structure in the Solar Neighborhood through LAMOST K Dwarfs
• Calibrating the metallicity of M dwarfs in wide physical binaries with F-, G-, and K-primaries -- II: Carbon, oxygen, and odd-Z iron-peak abundances of the primary stars
• M-dwarf stars in the b294 field from the VISTA Variables in the Vía Láctea (VVV)
• A Wave-Corrected Assessment of the Local Midplane
• Modeling the vertical distribution of the Milky Way's flat subsystem objects
• Mapping the Milky Way with Gaia Bp/Rp spectra-IV: the broken and asymmetric density profile of the stellar disk traced by a large sample of red clumps
• The Calar Alto CAFOS Direct Imaging First Data Release