Flat galaxy rotation curves Flat galaxy rotation curves naturally follow from dark matter filaments naturally follow from dark matter filaments Felipe J. Llanes­Estrada Felipe J. Llanes­Estrada Dept. Física Teórica & IPARCOS Dept. Física Teórica & IPARCOS Univ. Complutense de Madrid Univ. Complutense de Madrid Abstract Spiral­galaxy v(r) rotation curves look flat (constant v) unlike Kepler's 3rd law in 3­dim. They are however natural in 2 dimensions. In our world, this is achievable with cylindrical symmetry. If cosmological scale filaments extend to galactic scale, the velocity will be constant indefinitely; if instead there are dark matter haloes which are prolate, eventually v(r) should be observed to decrease with r. ✔ Further reading: preprint DOI: 10.13140/RG.2.2.35022.41289 ✔Work supported with funding by grant MINECO:FPA2016­75654­C2­1­P (Spain) & UCM under research group 910309 and its Institute for Particle and Cosmological Physics (IPARCOS) Want to listen to it? https://youtu.be/5nxy38gXEyQ Want to listen to it? https://youtu.be/HvZhCvnuJYY Spiral galaxy rotation curves Unlike Kepler's are flat 3rd planetary law Vera Rubin et al. Astron.J. 118 (1999) 236­260 SPARC data 1 2 1 3 4 Presented at the virtual conference “Galaxy Formation and Evolution in the Era of the Nancy Grace Roman Space Telescope” October 5th­9th 2020 based on preprint DOI: 10.13140/RG.2.2.35022.41289 One conventional explanation: spherical dark matter haloes Weber and de Boer, A&A 509, A25 (2010) Fits to simulations give profiles that only momentarily look isothermal (exponent = ­2) Additionally, cusp­core problem isothermal profile v(r) = constant (sketch by CTA observatory) Dark matter remains hidden and not for lack of searching Want to listen to it? https://youtu.be/s0AtB0iSCfU 2nd conventional explanation: MOND (Modified Newtonian Dynamics) My two pence: v(r) is constant if the source is not spherical, but rather cylindrical (But how would uninteracting dark matter thermalize?) Tully­Fisher: unexpected correlation between luminosity (ordinary matter) & rotation velocity (dark matter) Baryonic Tully­Fisher relation: Want to listen to it? https://youtu.be/nNec­I7RLes An exponent 4 is exactly predicted by MOND, that is constructed to explain rotation curves: by lowering the acceleration (taking its geometric mean with a constant) it is in effect lowering one dimension of r. A bit distasteful: Newton and Gauss's theory is very compelling and we have 3 dimensions, not 2. Additionally, MOND runs into large­scale cosmological problems. F~1/r implies v= √(2Gλ)=constant (λ is the linear mass density) R Adding a sphere (normal matter) to the filament: Cylinder thickness? Compelling 0th order physics! 4 7 5 What if…? Observational consequences Want to listen to it? https://youtu.be/QcisEL6Eh70 Want to listen to it? https://youtu.be/NAOgvuOhkBg Want to listen to it? https://youtu.be/sK0rW­1TF10 6 Prolate Prolate dark matter haloes also flatten v(r), but not indefinitely Finite dark matter cylinder |z|< a Y. Sofue arXiv: 1504.05368 Vega-Ferrero, Yepes, Gottlöber, arXiv:1603.02256 DM simulations yield more prolate than oblate haloes Observational question: Observational question: can one establish that can one establish that break for spiral galaxies break for spiral galaxies (prolate haloes) or is v(r) (prolate haloes) or is v(r) indefinitely flat (filaments)? indefinitely flat (filaments)? Tully­Fisher baryon relation DM: search @ high latitude Imaging with grav. lensing: stacking galaxy pairs shows DM filament between next neighboors (not otherwise) Epps, Hudson, MNRAS. 468 2017 Helicoidal motion along a cylinder *Synchrotron radiation is small for finite R *Galactic aurora (Fermi bubbles?) What if…? Observational consequences Precession of orbital plane of objects outside disk M. Pawlowski arxiv 1802.02579 Accretion along narrow filaments could explain Milky Way anisotropic satellite distribution Virial theorem for small galaxy clusters threaded by orie