Towards a higher mass for NGC 1052DF2: an analysis based on full distribution functions
Abstract
It is demonstrated that the kinematics of the 10 star clusters in NGC 1052DF2 is compatible with a high dynamical mass close to those implied by the standard stellartohalomass ratio (SHMR). The analysis relies on a convenient form for the distribution function of projected phase space data, capturing nonGaussian features in the spread of true velocities of the mass tracers. A key ingredient is tidal stripping by the gravity of the apparently nearby larger galaxy, NGC 1052. Tidal stripping decreases the range of velocities of mass tracers, while only mildly lowering the total mass inside the trimming radius r_{tr}. The analysis is performed assuming halo profiles consistent with simulations of the ΛCDM model. For the fiducial value r_{tr} = 10 kpc, we find that the virial mass of the pretrimmed halo is M< 1.6× 10^{10} M_⊙ at 2σ (95 per cent) and M< 8.6× 10^{9} M_⊙ at 1.64σ (90 per cent). For the mass within 10 kpc we obtain, M_10kpc< 3.9× 10^{9} M_⊙ and < 2.9× 10^{9} M_⊙ at 2σ and 1.64σ, respectively. The 2σ upper limit on the virial mass is roughly a factor of 35 below the mean SHMR relation.Taking r_{tr} = 20 kpc lowers the 2σ virial mass limits by a factor of ∼4, bringing our results closer to those of Wasserman et al. (2018) without their SHMR prior.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 March 2019
 DOI:
 10.1093/mnras/sty3532
 arXiv:
 arXiv:1810.03864
 Bibcode:
 2019MNRAS.484..510N
 Keywords:

 galaxies: haloes;
 dark matter;
 cosmology: theory;
 Astrophysics  Astrophysics of Galaxies
 EPrint:
 Agrees with accepted version. 10 pages, 10 figures