NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-22 T14:15:47 PDT
Help | Comment | NED Home

For refcode 2018MNRAS.476.3816F:
Retrieve 9 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by Royal Astronomical Society. 2018MNRAS.476.3816F Tidal stripping and the structure of dwarf galaxies in the Local Group Fattahi, Azadeh; Navarro, Julio F.; Frenk, Carlos S.; Oman, Kyle A.; Sawala, Till; Schaller, Matthieu Abstract. The shallow faint-end slope of the galaxy mass function is usually reproduced in Lambda cold dark matter (LambdaCDM) galaxy formation models by assuming that the fraction of baryons that turn into stars drops steeply with decreasing halo mass and essentially vanishes in haloes with maximum circular velocities V_max_ < 20-30 km s^-1^. Dark-matter-dominated dwarfs should therefore have characteristic velocities of about that value, unless they are small enough to probe only the rising part of the halo circular velocity curve (i.e. half-mass radii, r_1/2_ << 1 kpc). Many dwarfs have properties in disagreement with this prediction: they are large enough to probe their halo V_max_ but their characteristic velocities are well below 20 km s^-1^. These 'cold faint giants' (an extreme example is the recently discovered Crater 2 Milky Way satellite) can only be reconciled with our LambdaCDM models if they are the remnants of once massive objects heavily affected by tidal stripping. We examine this possibility using the APOSTLE cosmological hydrodynamical simulations of the Local Group. Assuming that low-velocity-dispersion satellites have been affected by stripping, we infer their progenitor masses, radii, and velocity dispersions, and find them in remarkable agreement with those of isolated dwarfs. Tidal stripping also explains the large scatter in the mass discrepancy-acceleration relation in the dwarf galaxy regime: tides remove preferentially dark matter from satellite galaxies, lowering their accelerations below the a_min_ ~ 10^-11^ m s^-2^ minimum expected for isolated dwarfs. In many cases, the resulting velocity dispersions are inconsistent with the predictions from Modified Newtonian Dynamics, a result that poses a possibly insurmountable challenge to that scenario. Key words: galaxies: dwarf, galaxies: evolution, galaxies: kinematics and dynamics, Local Group, dark matter
Retrieve 9 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home