The SLUGGS Survey: outer triaxiality of the Fast Rotator elliptical NGC 4473

Abstract

Systematic surveys of nearby early type galaxies (ETGs) using integral field unit spectrograph (IFU) data have revealed that galaxies can hide interesting structures only visible through kinematic studies. As part of their pioneering work, the ATLAS3D team have shown that most morphologically elliptical galaxies are centrally kinematically disk-like. Hence, while global morphology suggests that ellipticals are ellipsoidal/triaxial in shape, their central kinematics may be consistent with (inclined) oblate systems. Here we study the Fast Rotator elliptical galaxy: NGC 4473. Using slitlets, we obtain galaxy light kinematics out to unprecedentedly large galactocentric radii (2.5 effective radii). While we confirm the IFU results in the central regions, we find that at large galactocentric radii NGC 4473 exhibits a kinematic transition. In the outskirts, we observe clear minor and major axis rotation, a tell-tale sign of triaxiality, which agrees well with the galaxy's Hubble type. This outer "kinematically distinct halo" (KDH) may be expected from simulations of galaxy formation, and in this system contains around one-third of the stellar light. While this galaxy may be a special case, it suggests further investigation of the outskirts of galaxies is needed to confirm the new paradigm of galaxy classification.

6 pages, 3 figures, accepted for publication in MNRAS

References in corpus (7)

• 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
• Kinematic properties of early-type galaxy haloes using planetary nebulae
• The Structures of Distant Galaxies - III: The Merger History of over 20,000 Massive Galaxies at z < 1.2
• Gemini/GMOS Spectroscopy of the Spheroid and Globular Cluster System of NGC 3923
• The Nuclear Orbital Distribution in Galaxies as Fossil Record of Black Hole Formation from Integral-Field Spectroscopy
• Shapes of Stellar Systems and Dark Halos from Simulations of Galaxy Major Mergers

Cited by in corpus (31)

• Structure and Kinematics of Early-Type Galaxies from Integral-Field Spectroscopy
• The SAGES Legacy Unifying Globulars and GalaxieS Survey (SLUGGS): Sample definition, methods, and initial results
• The SAMI Galaxy Survey: the link between angular momentum and optical morphology
• The SLUGGS Survey: Wide-field Stellar Kinematics 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
• The Next Generation Virgo Cluster Survey. VI. The Kinematics of Ultra-compact Dwarfs and Globular Clusters in M87
• The SLUGGS survey: Exploring the metallicity gradients of nearby early-type galaxies to large radii
• Dominant dark matter and a counter rotating disc: MUSE view of the low luminosity S0 galaxy NGC 5102
• The extended Planetary Nebula Spectrograph (ePN.S) early-type galaxy survey. The kinematic diversity of stellar halos and the relation between halo transition scale and stellar mass
• The SLUGGS Survey: stellar kinematics, kinemetry and trends at large radii in 25 early-type galaxies
• Simulating multiple merger pathways to the central kinematics of early-type galaxies
• Decoupling the rotation of stars and gas -- I: the relationship with morphology and halo spin
• The Stellar Haloes of Massive Elliptical Galaxies III: Kinematics at Large Radius
• CALIFA reveals Prolate Rotation in Massive Early-type Galaxies: A Polar Galaxy Merger Origin?
• Implications for the origin of dwarf early-type galaxies: a detailed look at the isolated rotating dwarf early-type galaxy CG 611, with ramifications for the Fundamental Plane's (S_K)^2 kinematic scaling and the spin-ellipticity diagram
• The SLUGGS survey: Using extended stellar kinematics to disentangle the formation histories of low mass S0 galaxies
• The effects of stellar dynamics on the X-ray emission of flat early-type galaxies
• The SLUGGS Survey: The Assembly Histories of Individual Early-type Galaxies
• The SLUGGS survey: combining stars, globular clusters and planetary nebulae to understand the assembly history of early-type galaxies from their large radii kinematics
• A numerical twist on the observational spin parameter, ${\lambda }_R$
• Dark Matter Deprivation in Field Elliptical Galaxy NGC 7507
• The Mystery of the $\sigma$-Bump -- A new Signature for Major Mergers in Early-type Galaxies?
• The SLUGGS Survey: Trails of SLUGGS galaxies in a modified spin-ellipticity diagram
• The assembly history of the nearest S0 galaxy NGC 3115 from its kinematics out to six half-light radii
• On the assembly history of massive galaxies. A pilot project with VEGAS deep imaging and M3G integral field spectroscopy
• An efficient positive potential-density pair expansion for modelling galaxies
• The SLUGGS survey: chromo-dynamical modelling of the lenticular galaxy NGC 1023
• The SLUGGS Survey: Globular cluster kinematics in a "double sigma" galaxy - NGC 4473
• Orbit properties of massive prolate galaxies in the Illustris simulation
• Virial models and Anisotropy of Velocity Dispersion in e-galaxies
• The SLUGGS survey: a new mask design to reconstruct the stellar populations and kinematics of both inner and outer galaxy regions