VIMOS mosaic integral-field spectroscopy of the bulge and disk of the early-type galaxy NGC 4697

Abstract

We present an integral field study of the internal structure, kinematics and stellar population of the almost edge-on, intermediate luminosity ($L_{\ast }$) elliptical galaxy NGC 4697. We build extended 2-dimensional (2D) maps of the stellar kinematics and line-strengths of the galaxy up to $\sim 0.7$ effective radii (R${}_{eff}$) using a mosaic of 8 VIMOS (VIsible Multi-Objects Spectrograph on the VLT) integral-field unit pointings. We find clear evidence for a rotation-supported structure along the major axis from the 2D kinematical maps, confirming the previous classification of this system as a `fast-rotator'. We study the correlations between the third and fourth Gauss-Hermite moments of the line-of-sight velocity distribution (LOSVD) $h_3$ and $h_4$ with the rotation parameter ($V/\sigma$), and compare our findings to hydrodynamical simulations. We find remarkable similarities to predictions from gas-rich mergers. Based on photometry, we perform a bulge/disk decomposition and study the stellar population properties of the two components. The bulge and the disk show different stellar populations, with the stars in the bulge being older (age${}_{\mathrm{bulge}}=13.5_{-1.4}^{+1.4}$ Gyr, age${}_{\mathrm{disk}}=10.5_{-2.0}^{+1.6}$Gyr) and more metal-poor ($[M/H{]}_{\mathrm{bulge}}=-0.17_{-0.1}^{+0.12}$, $[M/H{]}_{\mathrm{disk}}=-0.03_{-0.1}^{+0.02}$). The evidence of a later-formed, more metal-rich disk embedded in an older, more metal-poor bulge, together with the LOSVD structure, supports a mass assembly scenario dominated by gas-rich minor mergers and possibly with a late gas-rich major merger that left a previously rapidly rotating system unchanged. The bulge and the disk do not show signs of different stellar Initial Mass Function slopes, and both match well with a Milky Way-like IMF.

Accepted for publication on MNRAS

References in corpus (22)

• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• The SAURON project -- IX. A kinematic classification for early-type galaxies
• A systematic variation of the stellar initial mass function in early-type galaxies
• The influence of gas on the structure of merger remnants
• CALIFA: a diameter-selected sample for an integral field spectroscopy galaxy survey
• Kinematic properties of early-type galaxy haloes using planetary nebulae
• The SAURON project - XII. Kinematic substructures in early-type galaxies: evidence for disks in fast rotators
• Stellar Population gradients in galaxy discs from the CALIFA survey
• The SAURON project - VI. Line strength maps of 48 elliptical and lenticular galaxies
• Radial variations in the stellar initial mass function of early-type galaxies
• The SAGES Legacy Unifying Globulars and GalaxieS Survey (SLUGGS): Sample definition, methods, and initial results
• The PN.S Elliptical Galaxy Survey: the dark matter in NGC 4494
• The stellar population histories of early-type galaxies. III. The Coma Cluster
• The SINFONI Nearby Elliptical Lens Locator Survey: Discovery of two new low-redshift strong lenses and implications for the initial mass function in giant early-type galaxies
• Dark matter content and internal dynamics of NGC 4697: NMAGIC particle models from slit data and planetary nebulae velocities
• The SAMI Pilot Survey: The Kinematic Morphology-Density Relation in Abell 85, Abell 168 and Abell 2399
• Two-dimensional kinematics of SLACS lenses: I. Phase-space analysis of the early-type galaxy SDSS J2321-097 at z=0.1
• Systematic variations of central mass density slopes in early-type galaxies
• Stellar orbits in cosmological galaxy simulations: the connection to formation history and line-of-sight kinematics
• Stellar population gradients in early-type cluster galaxies with VIMOS IFU
• Spectral decomposition of the stellar kinematics in the polar disk galaxy NGC 4650A
• An Oxford SWIFT Integral Field Spectroscopy study of 14 early-type galaxies in the Coma cluster

Cited by in corpus (9)

• The Stellar Initial Mass Function in Early-Type Galaxies from Absorption Line Spectroscopy. III. Radial Gradients
• The SAMI Galaxy Survey: Revisiting Galaxy Classification Through High-Order Stellar Kinematics
• SDSS-IV MaNGA: environmental dependence of stellar age and metallicity gradients in nearby galaxies
• 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: Using extended stellar kinematics to disentangle the formation histories of low mass S0 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
• Globular Cluster Systems and X-Ray Atmospheres in Galaxies
• Elliptical (E) and ellicular (ES) galaxies in the M_bh-M_*,sph diagram, and a merger-driven explanation for the origin of ES galaxies, anti-truncated stellar discs in lenticular galaxies, and the Sersicification of E galaxy light profiles