IS DARK MATTER FACT OR FANTASY { CLUES FROM THE DATA Philip D. Mannheim University of Connecticut Seminar at Miami 2018, Fort Lauderdale December 2018 1 THE HUNDRED YEAR DARK MATTER PROBLEM Almost as soon as it was realized the Milky Way was a galaxy, in the 1920s Oort found that the velocities of stars perpendicular to the plane of the galaxy had a missing mass problem. Almost as soon as it was realized that there were other galaxies, in the 1930s Zwicky and Smith found that the velocity dispersions of galaxies in a cluster of galaxies had a missing mass problem. Three possibilities: more galaxies than one could see, lack of virialization because of corre- lation energy, breakdown of Newton's Law of Gravity on large distance scales. In the 1970s HI radio studies of Freeman and of Roberts and Whitehurst and HII opti- cal studies of Rubin, Ford and Thonnard showed the measured rotational velocities in the outskirts of spiral galaxies greatly exceeded the luminous Newtonian expectations. Then the dam broke, with missing mass problems all the way up to cosmology. And a brand new problem to boot { dark energy. 2 Two possible astrophysical options for dark matter: faint (need better tele- scopes { now ruled out). Dead (black holes, white dwarfs { MACHOS) Ruled out by gravitational lensing off the Magellanic clouds. One particle physics option for dark matter: particles that are intrinsically unable to emit light (neutrinos, supersymmetric particles, axions, dark pho- tons { WIMPS). Extensive, decades long accelerator and underground searches have yet to find any Wimps. Not ruled out but far from being ruled in, though there is a tension for supersymmetry since no superparticles found at LHC that could solve the elementary Higgs boson hierarchy problem. 3 Additionally no solution to the dark energy/cosmological constant problem found either in the twenty years now since the discovery of the accelerating Universe. Though problem predates the accelerating Universe. 60 And if ΩΛ really is of order 10 then none of the CMB background or fluctuation tests would be successful. In fact they would actually be some of the worst if not the worst fits in the history of physics. And lurking behind all this is the hope that the standard Newton-Einstein classical gravity expectations are not destroyed by quantum mechanics. (That gravity knows about large scale quantum effects is evidenced by the stabilizing Pauli degeneracy of electrons in a white dwarf and the intrinsically quantum mechanical CMB black body radiation spectrum.) To see what to do look for clues from the data { focus on galactic rotation curves of spirals since no theory needed { just orbits. Start with solar system wisdom { more sources (Neptune) or new theory (Mercury). 4 Keplerian expectation for planetary orbital velocities { Mercury and Uranus problems 5 Face on view of a spiral galaxy 6 Edge on view of a spiral galaxy 7 70 60 50 40 30 20 10 DDO 154 0 0 2 4 6 8 NGC 3198 and DDO 154 rotation velocities from HI data 8 TO FIX THINGS UP ASSUME DARK MATTER Need dark matter where there is little luminous matter. Not a small effect at all. Dark to luminous mass ratio in a bright spiral (NGC 3198) is of order two to one, and thus four to one in potential. Dark to luminous mass ratio in a dwarf spiral (DDO 154) is of order three to one, and thus nine to one in potential. Dark to luminous ratio not universal. Bright spiral rotation curves are flat, dwarf spiral rotation curves are rising. Thus the case where dark matter dominates is the one where rotation curves are not flat but rising, with dark matter being needed in the inner region. Dwarfs thus show the dark matter problem in its starkest form. To make dark matter halo fits work for bright spirals need two free parameters per halo (e.g. Navarro-Frenk-White NFW dark matter theory profile). One parameter to match asymptotic value of velocity to inner region and second parameter to keep velocity constant in between. Also need two parameters per halo for dwarfs. Thus for 138 well-studied galaxies discussed below (need good HII to get luminous distribution and good HI to get velocity distribution) need 276 free dark matter halo parameters. 9 DIFFICULTIES FOR DARK MATTER THEORY For the moment dark matter halo parameters are not derived from dark matter theory, and basically parameterize the data { you show me the velocity and I will tell you the amount of dark matter. Objective: to make dark matter falsifiable require: YOU SHOW ME THE LUMINOUS DISTRIBUTION AND I WILL TELL YOU THE VELOCITY Thus dark matter theory does not know a priori how to match any given halo with any given luminous distribution. WHY { BECAUSE GALAXIES OBEY TULLY- FISHER RELATION. Find that v4=L is universal in spiral galaxies. Thus velocity (due to the full gravitational potential) is correlated with the luminous distribution. Thus to get Tully Fisher would need dark to luminous ratio to be universal, but it is not, so need to tune halo parameters galaxy by galaxy. So let us look for other regularities, to see what we can pull out of the 138 galaxy sample. Find that v2=c2R at last data point is universal, and not only that, it is of cosmological magnitude. 10 100 140 150 120 80 100 100 60 80 60 40 50 40 20 20 IC 2574 NGC 925 NGC 2403 0 0 0 0 2 4 6 8 10 12 0 2 4 6 8 10 12 0 5 10 15 20 100 300 250 200 250 80 200 150 200 60 150 150 100 40 100 100 50 20 50 50 NGC 2841 NGC 2903 NGC 2976 NGC 3031 0 0 0 0 0 10 20 30 40 50 0 5 10 15 20 25 30 0.0 0.5 1.0 1.5 2.0 2.5 0 2 4 6 8 10 12 14 250 200 150 150 200 150 150 100 100 100 100 50 50 50 50 NGC 3198 NGC 3521 NGC 3621 NGC 3627 0 0 0 0 0 10 20 30 0 5 10 15 20 25 30 35 0 5 10 15 20 25 0 2 4 6 8 200 250 200 200 150 200 150 150 150 100 100 100 100 50 50 50 50 NGC 4736 NGC 4826 NGC 5055 NGC 6946 0 0 0 0 0 2 4 6 8 10 0 5 10 15 0 10 20 30 40 0 5 10 15 20 140 250 120 200 100 80 150 60 100 40 70 50 20 NGC 7331 60NGC 7793 0 0 0 5 10 15 20 0 2 4 6 8 10 50 −1 FIG. 1: Fitting to40 the rotational velocities (in km sec ) of the THINGS 18 galaxy sample 30 20 10 DDO 154 0 0 2 4 6 8 11 140 200 120 150 150 100 80 100 100 60 40 50 50 20 NGC 3726 NGC 3769 NGC 3877 0 0 0 0 5 10 15 20 25 30 0 5 10 15 20 25 30 0 2 4 6 8 10 200 150 150 150 100 100 100 50 50 50 NGC 3893 NGC 3917 NGC 3949 0 0 0 0 5 10 15 20 0 2 4 6 8 10 12 14 0 1 2 3 4 5 6 7 250 140 250 200 120 200 100 150 80 150 100 60 100 40 50 50 20 NGC 3953 NGC 3972 NGC 3992 0 0 0 0 5 10 15 0 2 4 6 8 0 10 20 30 40 50 140 200 120 150 100 150 80 100 60 100 40 50 50 20 NGC 4010 NGC 4013 NGC 4051 0 0 0 0 2 4 6 8 10 0 5 10 15 20 25 30 0 2 4 6 8 10 200 150 200 150 150 100 100 100 50 50 50 NGC 4085 NGC 4088 NGC 4100 0 0 0 0 1 2 3 4 5 6 0 5 10 15 0 5 10 15 20 25 FIG. 2: Fitting to the rotational velocities of the Ursa Major 30 galaxy sample { Part 1 12 140 200 200 120 150 150 100 80 100 100 60 40 50 50 20 NGC 4138 NGC 4157 NGC 4183 0 0 0 0 5 10 15 0 5 10 15 20 25 30 0 5 10 15 200 120 100 100 150 80 80 60 100 60 40 40 50 20 20 NGC 4217 NGC 4389 UGC 6399 0 0 0 0 5 10 15 0 1 2 3 4 0 2 4 6 8 100 100 80 80 80 60 60 60 40 40 40 20 20 20 UGC 6446 UGC 6667 UGC 6818 0 0 0 0 2 4 6 8 10 12 0 2 4 6 8 0 2 4 6 8 100 120 120 100 80 100 80 80 60 60 60 40 40 40 20 20 20 UGC 6917 UGC 6923 UGC 6930 0 0 0 0 2 4 6 8 10 0 1 2 3 4 5 0 5 10 15 100 120 200 100 80 150 80 60 60 100 40 40 50 20 20 UGC 6973 UGC 6983 UGC 7089 0 0 0 0 2 4 6 8 10 0 5 10 15 0 1 2 3 4 5 6 7 FIG. 3: Fitting to the rotational velocities of the Ursa Major 30 galaxy sample { Part 2 13 120 80 120 120 100 100 100 60 80 80 80 60 60 40 60 40 40 40 20 20 20 20 DDO 64 F 563-1 F 563-V2 F 568-3 0 0 0 0 0.0 0.5 1.0 1.5 2.0 0 5 10 15 0 1 2 3 4 5 6 0 2 4 6 8 10 50 100 100 80 40 80 80 60 60 30 60 40 40 20 40 20 20 20 10 F 583-1 F 583-4 NGC 959 NGC 4395 0 0 0 0 0 2 4 6 8 10 12 14 0 1 2 3 4 5 6 7 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.2 0.4 0.6 0.8 120 140 120 80 120 100 100 60 100 80 80 80 60 40 60 60 40 40 40 20 20 20 20 NGC 7137 UGC 128 UGC 191 UGC 477 0 0 0 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0 10 20 30 40 50 0.0 0.5 1.0 1.5 2.0 0 2 4 6 8 10 120 50 100 120 100 40 80 100 80 30 60 80 60 60 20 40 40 40 10 20 20 20 UGC 1230 UGC 1281 UGC 1551 UGC 4325 0 0 0 0 0 5 10 15 20 25 30 35 0.0 0.5 1.0 1.5 0 1 2 3 4 5 6 0.0 0.5 1.0 1.5 2.0 2.5 3.0 120 120 80 100 150 100 80 60 80 100 60 60 40 40 40 50 20 20 20 UGC 5005 UGC 5750 UGC 5999 UGC 11820 0 0 0 0 0 5 10 15 20 25 0 2 4 6 8 0 2 4 6 8 10 12 14 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 FIG.