Kinematic properties of the field elliptical NGC 7507

The dark matter (DM) halos of field elliptical galaxies have n ot been well studied and their properties appear controvers ial in the literature. While some galaxies appear to be nearly devoid of DM, others show clear evidence of its presence. Furthermore, modified Netonian dynamics (MOND), which has been found to have predictive power in the domain of disk galaxies, has not yet been investigated for isolated elliptical galaxies. We study th e kinematics of the isolated elliptical NGC 7507, which has been claimed as a clear example of DM presence in early-type galaxies. We obtained major and minor axis long-slit spectroscopy of NGC 7507 using the Gemini South telescope and deep imaging in Kron-Cousins R and Washington C using the CTIO/MOSAIC camera. Mean velocities, velocity dispersion and higher order moments o f the velocity distribution are measured out to∼90 ′′ . The galaxy, although almost circular, has significant rotation along the minor ax is and a rapidly declining velocity dispersion along both axes. The velocity dispersion profile is modeled in the context of a spherical Je ans analysis. Models without DM provide an excellent representation of the data with a mass-to-light ratio ( M/L) of 3.1 (R-band). The most massive Navarro-Frenk-White (NFW) halo the data allow has a virial mass of only 3.9 +3.1