The so-called ultra-diffuse galaxy NGC 1052-DF2 was announced to be a galaxy lacking dark matter based on a spectroscopic study of its constituent globular clusters .
Here we present the first spectroscopic analysis of the stellar body of this galaxy using the MUSE integral-field spectrograph at the ( ESO ) Very Large Telescope .
The MUSE datacube simultaneously provides DF2 ’ s stellar velocity field and systemic velocities for seven globular clusters ( GCs ) .
We further discovered three planetary nebulae ( PNe ) that are likely part of this galaxy .
While five of the clusters had velocities measured in the literature , we were able to confirm the membership of two more candidates through precise radial velocity measurements , which increases the measured specific frequency of GCs in DF2 .
The mean velocity of the diffuse stellar body , 1792.9 ^ { -1.8 } _ { +1.4 } \mbox { km s } ^ { -1 } , is consistent with the mean globular cluster velocity .
We detect a weak but significant velocity gradient within the stellar body , with a kinematic axis close to the photometric major axis , making it a prolate-like rotator .
We estimate a velocity dispersion from the clusters and PNe of \sigma _ { \mathrm { int } } = 10.6 ^ { +3.9 } _ { -2.3 } \mbox { km s } ^ { -1 } .
The velocity dispersion \sigma _ { DF 2 \star } ( R _ { \mathrm { e } } ) for the stellar body within one effective radius is 10.8 ^ { -4.0 } _ { +3.2 } \mbox { km s } ^ { -1 } .
Considering various sources of systemic uncertainties , this central value varies between 5 and 13 \mbox { km s } ^ { -1 } , and we conservatively report a 95 % confidence upper limit to the dispersion within one R _ { \mathrm { e } } of 21 \mbox { km s } ^ { -1 } .
We provide updated mass estimates based on these dispersions corresponding to the different distances to NGC 1052-DF2 that have been reported in the recent literature .