The low dark matter content of the lenticular galaxy NGC 3998

Abstract

We observed the lenticular galaxy NGC 3998 with the Mitchell Integral-Field Spectrograph and extracted line-of-sight velocity distributions out to 3 half-light radii. We constructed collisionless orbit models in order to constrain NGC 3998's dark and visible structure, using kinematics from both the Mitchell and SAURON instruments. We find NGC 3998 to be almost axisymmetric, seen nearly face on with a flattened intrinsic shape - i.e., a face-on fast-rotator. We find an I-band mass-to-light ratio of $4.7_{-0.45}^{+0.32}$ in good agreement with previous spectral fitting results for this galaxy. Our best-fit orbit model shows a both a bulge and a disc component, with a non-negligible counter-rotating component also evident. We find that relatively little dark matter is needed to model this galaxy, with an inferred dark mass fraction of just $(7.1_{-7.1}^{+8.1})\%$ within one half-light radius.

17 pages, 21 figures, accepted by MNRAS

References in corpus (14)

• K-corrections and filter transformations in the ultraviolet, optical, and near infrared
• The SAURON project -- IX. A kinematic classification for early-type galaxies
• The SAURON project -- X. The orbital anisotropy of elliptical and lenticular galaxies: revisiting the (V/sigma,epsilon) diagram with integral-field stellar kinematics
• Measuring the inclination and mass-to-light ratio of axisymmetric galaxies via anisotropic Jeans models of stellar kinematics
• The Atlas3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies
• Triaxial orbit based galaxy models with an application to the (apparent) decoupled core galaxy NGC 4365
• Multiple minor mergers: formation of elliptical galaxies and constraints for the growth of spiral disks
• The Atlas3D project - XXIV. The intrinsic shape distribution of early-type galaxies
• Small scatter and nearly-isothermal mass profiles to four half-light radii from two-dimensional stellar dynamics of early-type galaxies
• Recovering the intrinsic shape of early-type galaxies
• Recovery of the internal orbital structure of galaxies
• Stellar orbits in cosmological galaxy simulations: the connection to formation history and line-of-sight kinematics
• The Stellar Haloes of Massive Elliptical Galaxies III: Kinematics at Large Radius
• The Inside-out Growth of the Most Massive Galaxies at 0.3<z<0.9

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