The Galaxy in Context: Structural, Kinematic, and Integrated Properties

By Joss Bland-Hawthorn, O. Gerhard. 2016

1,128 citations recorded by the source corpus.

Our Galaxy, the Milky Way, is a benchmark for understanding disk galaxies. It is the only galaxy whose formation history can be studied using the full distribution of stars from faint dwarfs to supergiants. The oldest components provide us with unique insight into how galaxies form and evolve over billions of years. The Galaxy is a luminous (L⋆) barred spiral with a central box/peanut bulge, a dominant disk, and a diffuse stellar halo. Based on global properties, it falls in the sparsely populated “green valley” region of the galaxy color-magnitude diagram. Here we review the key integrated, structural and kinematic parameters of the Galaxy, and point to uncertainties as well as directions for future progress. Galactic studies will continue to play a fundamental role far into the future because there are measurements that can only be made in the near field and much of contemporary astrophysics depends on such observations.

Subfields: Astronomy and Astrophysics, Instrumentation

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Citations in the corpus

Gaia DR2 proper motions of dwarf galaxies within 420 kpc (2018, background): “…respect to the Milky Way center of (11±1, 248±3, 7.3±0.5) km/s in a reference frame in which the x-axis is positive pointing inwards from the Sun to the Galactic center, the y-axis in the direction of Galactic rotation and the z-axis towards the North Galactic Cap (Bland-Hawthorn & Gerhard 2016).”
The milky way total mass profile as inferred from Gaia DR2 (2019, methodology): “When deriving the scale-length for both the thin and thick discs, we used the Gaussian prior given in the fourth column of Table 2, which is based on the typical scatter in Rd amongst different studies (see the compilation of measurements in Bland-Hawthorn & Gerhard 2016).”
THE SHAPE OF THE INNER MILKY WAY HALO FROM OBSERVATIONS OF THE PAL 5 AND GD–1 STELLAR STREAMS (2016, methodology): “Based on recent measurements of R0 (Chatzopoulos et al. 2015; Bland-Hawthorn & Gerhard 2016; Boehle et al. 2016), we use the constraint R0 = 8.1 ± 0.1 kpc.”
The Optical to Mid-infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS, and WISE Surveys (2019, background): “The Galactic center is an ideal region to investigate the IR extinction owing to the well-measured galactocentric distance (Bland-Hawthorn & Gerhard 2016; de Grijs & Bono 2016) and relatively high extinction.”
A geometric distance measurement to the Galactic center black hole with 0.3% uncertainty (2019, methodology): “L10, page 1 of 10 general recent overviews of R0 determinations, see Genzel et al. (2010) and Bland-Hawthorn & Gerhard (2016).”
Small-Scale Challenges to the ΛCDM Paradigm (2017, background): “Efforts are underway to disentangle disrupted satellites from other stars in the Milky Way halo via chemistry and kinematics (see Bland-Hawthorn & Gerhard 2016 for a recent review).”
The vertical metallicity gradients of mono-age stellar populations in the Milky Way with the RAVE and Gaia data (2017, methodology): “For each mono-age stellar population sample, we obtain the vertical height of stars |Z | from a distance calculated from the TGAS parallaxes and Galactic latitudes, assuming the vertical offset of the Sun to be Z = 25 pc (Bland-Hawthorn & Gerhard 2016).”
Nuclear star clusters (2009, background): “However, we do not provide a comprehensive literature discussion for this object, as it is extensively covered by other recent reviews (Genzel et al. 2010; Schödel et al. 2014b; Bland-Hawthorn and Gerhard 2016).”
Theoretical Challenges in Galaxy Formation (2016, background): “Typically mass estimates are in the range of 1−2×1012M (Bland-Hawthorn & Gerhard 2016; Bovy et al. 2012; Li & White 2008; Watkins, Evans & An 2010; Xue et al. 2008).”
Three Hypervelocity White Dwarfs in Gaia DR2: Evidence for Dynamically Driven Double-degenerate Double-detonation Type Ia Supernovae (2018, positive): “We assume all the stars reside in the thin disk, with an exponential scale length of 2.6 kpc, an exponential scale height of 300 pc, and a normalization that yields a total stellar mass of 5 × 1010M (Bland-Hawthorn & Gerhard 2016).”
The SAGA Survey. I. Satellite Galaxy Populations around Eight Milky Way Analogs (2017, methodology): “The Milky Way is the most well-studied galaxy in the Universe (e.g., Bland-Hawthorn & Gerhard 2016).”
Farthest Neighbor: The Distant Milky Way Satellite Eridanus II (2016, background): “Eri II is likely located just beyond the virial radius of the Milky Way, which is typically estimated to be ∼300 kpc (Taylor et al. 2016; Bland-Hawthorn & Gerhard 2016).”
Constraining the Milky Way assembly history with Galactic Archaeology (2016, neutral): “A comprehensive discussion of the Galactic bar and spiral parameters can be found in the recent review by Bland-Hawthorn & Gerhard (2016).”
Measuring Radial Orbit Migration in the Galactic Disk (2018, methodology): “The radial scale length of the stellar disk of the Milky Way is not well constrained (see Bland-Hawthorn & Gerhard 2016 for a review).”
The age–metallicity structure of the Milky Way disc using APOGEE (2017, methodology): “The relative contribution of high to low [α/Fe] populations, fΣ, is 18%±5%, which is consistent with existing measurements (e.g. Bland-Hawthorn & Gerhard 2016).”
The Circumgalactic Medium (2017, result): “We note that a recent review by Bland-Hawthorn & Gerhard (2016) performed a similar radially-varying mass-budget compilation for the Milky Way and its halo and incorporates some of these same results.”