NGC 1399: a complex dynamical case

Abstract

Evidence for a disturbed velocity structure in the outer regions of the galaxy NGC1399 comes from a re-analysis of the planetary nebulae data from Arnaboldi et al. (1994). We find a strong rotation along a P.A.=140 degrees for R<=140'' which is followed by a rapid drop off at larger radii, where the velocity dispersion starts to increase. This kinematical behavior can be interpreted as an indication for an interaction scenario. Interaction is advocated in previous analysis of the halo regions of this system, based on different dynamical tracers such as globular clusters and X-rays, but in all these studies the mass distribution is derived under the equilibrium hypothesis, which is not appropriate when an interaction takes place. Here we attempt a non-equilibrium dynamical analysis of NGC1399: with a simple model and under the impulse approximation, we show that the observed kinematics is consistent with an energy injection caused by a flyby encounter of NGC 1399 with the nearby system NGC 1404. In this approach, we find a mass-to-light ratio, M/L_B=26 within R=400'', which is about half of that requested when equilibrium is assumed, i.e. M/L_B=56.

10 pages, 15 figures, accepted for pubblication in A&A

References in corpus (4)

• Deep ROSAT-HRI observations of the NGC 1399/NGC 1404 region: morphology and structure of the X-ray halo
• Signatures of Galaxy-Cluster Interactions: Spiral Galaxy Rotation Curve Asymmetry, Shape, and Extent
• Mass profiles and anisotropies of early-type galaxies
• Planetary nebulae as mass tracers of their parent galaxies: biases in the estimate of the kinematical quantities

Cited by in corpus (27)

• Kinematic properties of early-type galaxy haloes using planetary nebulae
• The Fornax Deep Survey with VST. I. The extended and diffuse stellar halo of NGC~1399 out to 192 kpc
• The Diffuse Light in Simulations of Galaxy Clusters
• The PN.S Elliptical Galaxy Survey: the dark matter in NGC 4494
• The Globular Cluster System of NGC 1399. II. Kinematics of a Large Sample of Globular Clusters
• Mapping the Dark Side with DEIMOS: Globular Clusters, X-ray Gas, and Dark Matter in the NGC 1407 Group
• Mass-to-light ratio gradients in early-type galaxy haloes
• The PN.S Elliptical Galaxy Survey: a standard LCDM halo around NGC 4374?
• The Kinematics and Dynamics of the Globular Clusters and the Planetary Nebulae of NGC 5128
• The Fornax Deep Survey with VST. VIII. Connecting the accretion history with the cluster density
• Dynamical evolution of globular cluster systems in clusters of galaxies I. The case of NGC 1404 in the Fornax cluster
• Testing Yukawa-like potentials from f(R)-gravity in elliptical galaxies
• The SLUGGS Survey: Breaking degeneracies between dark matter, anisotropy and the IMF using globular cluster subpopulations in the giant elliptical NGC 5846
• The MOND Fundamental Plane
• The Fornax Cluster VLT Spectroscopic Survey. I - VIMOS spectroscopy of compact stellar systems in the Fornax core region
• The Fornax Cluster VLT Spectroscopic Survey II - Planetary Nebulae kinematics within 200 kpc of the cluster core
• The Globular Cluster System of NGC 1399: III. VLT Spectroscopy and Database
• Dark matter in galaxies and growth of giant black holes
• The Fornax Cluster VLT Spectroscopic Survey III -- Kinematical characterisation of globular clusters across the Fornax galaxy cluster
• The global mass - to - light ratio of SLACS lenses
• Capturing the 3D Motion of an Infalling Galaxy via Fluid Dynamics
• The Fornax Cluster VLT Spectroscopic Survey IV -- Cold kinematical substructures in the Fornax core from COSTA
• Unifying static analysis of gravitational structures with a scale-dependent scalar field gravity as an alternative to dark matter
• Dark matter and alternative recipes for the missing mass
• Studying Dynamical Models of the Core Galaxy NGC 1399 with Merging Remnants
• COSTA: the COld STream finder Algorithm. Searching for kinematical substructures in the phase space of discrete tracers
• Probing the Environment with Galaxy Dynamics