ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model O B-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model I-Model I-Model I-Model I-Model B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model I-Model I-Model I-Model O O O O O O O O O O O O O B-Dataset I-Dataset I-Dataset I-Dataset I-Dataset I-Dataset I-Dataset O O O O O O O O O B-CelestialObject O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O B-Model I-Model I-Model I-Model O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O B-Model O B-Model O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation O O O O O B-Citation I-Citation B-Citation I-Citation O B-Citation I-Citation O O O O O B-CelestialObject O O O O O O O B-CelestialObjectRegion I-CelestialObjectRegion I-CelestialObjectRegion I-CelestialObjectRegion B-Citation I-Citation I-Citation I-Citation O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
tokens: would either require a larger sample of observed dwarf galaxies with smaller error bars and systematic errors of (a difficult prospect) or obtaining spatially resolved rotation curves for 400 pc (within the half-light radii) in small dwarfs, where Fig. 9 shows that CDM/WDM and SIDM/SIWDM could be differentiated. While the differences between DM models in Fig. 10 are marginal, the diversity in the observed population does appear greater than what we find in the suite of simulated dwarfs. Two field dwarfs, Cetus and IC 1613, have derived V 1/2 values that are lower than the 68 confidence region of the analytic fit. While the low V 1/2 values would be more consistent with a lower halo mass, the large sizes of these dwarfs are not expected for a lower halo mass given our simulations’ M halo – r 1/2 relation. Read et al. ( 2016b ) have noted that the gas morphology of IC 1613 implies a state of disequilibrium, which may explain why it is not consistent with our expected relation. A systematic difference in V circ (e.g. from the observed V circ underestimating the true V circ ; Verbeke et al. 2017 ; Oman et al. 2019 ) would explain the difference. We note, however, that we are plotting observationally determined V circ values that are derived from the galaxy kinematics, not from the underlying gravitational potential, for the simulations as well. Moreover, there are other FIRE -2 CDM simulations that agree fairly well with the two points with low V 1/2 values. Chan et al. ( 2018 )’s sample of ultra-diffuse dwarfs () occupy the same space as Cetus and IC 1613, with r 1/2 ∼ 2 kpc and V 1/2 ∼ 20 km s −1 , and the suite of ultra-faint dwarfs in Wheeler et al. (2019 ) contains a number of dwarfs that are directly in line with the analytic fits for haloes with . The two ‘compact’ dwarfs with high V 1/2 values and small half-light radii, Tucana and NGC 6822, are also difficult to explain with the results of our suite. Both reside much further outside the confidence region than the dwarfs with low V 1/2 values. Though our suite of simulations is not part of a Local-Group-like environment, FIRE -2 ΛCDM simulations that simulate LG analogues have found similar difficulty matching high V 1/2 values for isolated dwarf galaxies: Garrison-Kimmel et al. ( 2018 ) found no counterparts in the ELVIS on FIRE suite to observed ‘compact’ dwarfs with high V 1/2 values and small r 1/2 values (e.g.Tucana, NGC 6822, and even satellites such as NGC 205, NGC 147, and IC 10). It has been argued that Tucana has had a previous passage through the MW or M31 disc (Teyssier, Johnston Kuhlen 2012 ), which could invalidate the assumptions of Wolf et al. ( 2010 ) used to derive its V 1/2 . Finally, it is worth noting that the role of ‘chaos’ – more precisely, sensitivity of high-level results to very small numerical changes – could be significant when studying the combined effects of dark matter physics and hydrodynamics. This issue has not been studied extensively, but recent work by