Alfred L. Tiley
The Shapes of the Rotation Curves of Star-forming Galaxies Over the Last ≈ 10 Gyr
Tiley, Alfred L.; Swinbank, A.M.; Harrison, C.M.; Smail, Ian; Turner, O.J.; Schaller, M.; Stott, J.P.; Sobral, D.; Theuns, T.; Sharples, R.M.; Gillman, S.; Bower, R.G.; Bunker, A.J.; Best, P.; Richard, J.; Bacon, Roland; Bureau, M.; Cirasuolo, M.; Magdis, G.
Professor Mark Swinbank firstname.lastname@example.org
Professor Ian Smail email@example.com
Professor Tom Theuns firstname.lastname@example.org
Professor Ray Sharples email@example.com
We analyse maps of the spatially-resolved nebular emission of ≈1500 star-forming galaxies at z ≈ 0.6–2.2 from deep KMOS and MUSE observations to measure the average shape of their rotation curves. We use these to test claims for declining rotation curves at large radii in galaxies at z ≈ 1–2 that have been interpreted as evidence for an absence of dark matter. We show that the shape of the average rotation curves, and the extent to which they decline beyond their peak velocities, depends upon the normalisation prescription used to construct the average curve. Normalising in size by the galaxy stellar disk-scale length after accounting for seeing effects (R′d), we construct stacked position-velocity diagrams that trace the average galaxy rotation curve out to 6R′d (≈13 kpc, on average). Combining these curves with average HI rotation curves for local systems, we investigate how the shapes of galaxy rotation curves evolve over ≈10 Gyr. The average rotation curve for galaxies binned in stellar mass, stellar surface mass density and/or redshift is approximately flat, or continues to rise, out to at least 6R′d. We find a trend between the outer slopes of galaxies’ rotation curves and their stellar mass surface densities, with the higher surface density systems exhibiting flatter rotation curves. Drawing comparisons with hydrodynamical simulations, we show that the average shapes of the rotation curves for our sample of massive, star-forming galaxies at z ≈ 0–2.2 are consistent with those expected from ΛCDM theory and imply dark matter fractions within 6Rd of at least ≈60 percent.
Tiley, A. L., Swinbank, A., Harrison, C., Smail, I., Turner, O., Schaller, M., …Magdis, G. (2019). The Shapes of the Rotation Curves of Star-forming Galaxies Over the Last ≈ 10 Gyr. Monthly Notices of the Royal Astronomical Society, 485(1), 934-960. https://doi.org/10.1093/mnras/stz428
|Journal Article Type||Article|
|Acceptance Date||Feb 5, 2019|
|Online Publication Date||Feb 13, 2019|
|Publication Date||May 1, 2019|
|Deposit Date||Feb 19, 2019|
|Publicly Available Date||Feb 19, 2019|
|Journal||Monthly Notices of the Royal Astronomical Society|
|Publisher||Royal Astronomical Society|
|Peer Reviewed||Peer Reviewed|
Accepted Journal Article
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
Published Journal Article
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