One Law to Rule Them All: The Radial Acceleration Relation of Galaxies

By F. Lelli, S. McGaugh, J. Schombert, M. Pawlowski. 2016

327 citations recorded by the source corpus.

We study the link between baryons and dark matter (DM) in 240 galaxies with spatially resolved kinematic data. Our sample spans 9 dex in stellar mass and includes all morphological types. We consider (1) 153 late-type galaxies (LTGs; spirals and irregulars) with gas rotation curves from the SPARC database, (2) 25 early-type galaxies (ETGs; ellipticals and lenticulars) with stellar and H i data from ATLAS 3 D or X-ray data from Chandra, and (3) 62 dwarf spheroidals (dSphs) with individual-star spectroscopy. We find that LTGs, ETGs, and “classical” dSphs follow the same radial acceleration relation: the observed acceleration ( g obs ) correlates with that expected from the distribution of baryons ( g bar ) over 4 dex. The relation coincides with the 1:1 line (no DM) at high accelerations but systematically deviates from unity below a critical scale of ∼10−10 m s−2. The observed scatter is remarkably small ( ≲ 0.13 dex) and largely driven by observational uncertainties. The residuals do not correlate with any global or local galaxy property (e.g., baryonic mass, gas fraction, and radius). The radial acceleration relation is tantamount to a natural law: when the baryonic contribution is measured, the rotation curve follows, and vice versa. Including ultrafaint dSphs, the relation may extend by another 2 dex and possibly flatten at g bar ≲ 10 − 12 m s−2, but these data are significantly more uncertain. The radial acceleration relation subsumes and generalizes several well-known dynamical properties of galaxies, like the Tully–Fisher and Faber–Jackson relations, the “baryon-halo” conspiracies, and Renzo’s rule.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/c9f1a882375da6a02ef8639d7ad73ad351993352

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In Astronomy and Astrophysics

  1. F. Lelli
  2. J. Schombert
  3. S. McGaugh
  4. Pengfei Li
  5. Pavel Kroupa
  6. Morgan Le Delliou
  7. Antonino Del Popolo
  8. B. Famaey

In Instrumentation

  1. F. Lelli
  2. J. Schombert
  3. S. McGaugh
  4. Pengfei Li
  5. P. Hopkins
  6. B. Famaey
  7. Pavel Kroupa
  8. L. Hernquist

In Nuclear and High Energy Physics

  1. J. Schombert
  2. F. Lelli
  3. S. McGaugh
  4. Pavel Kroupa
  5. Morgan Le Delliou
  6. Antonino Del Popolo
  7. Filippo Fraternali
  8. G. Mamon

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