Probing the Central Regions of Nearby Compact Elliptical Galaxies

Abstract

K-band spectroscopic observations recorded with NIFS+ALTAIR on Gemini North are used to probe the central arcsec of the compact elliptical galaxies NGC 4486B, NGC 5846A, and M32. The angular resolution of these data is ~0.1 arcsec FWHM. The central stellar contents of NGC 4486B and NGC 5846A are similar, in the sense that they occupy the same regions of the (Ca I, 12CO), (Na I, 12CO) and (13CO, 12CO) diagrams. The NGC 4486B and NGC 5846A observations depart from the sequence defined by solar neighborhood giants in the (Na I, 12CO) diagram, in a sense that is consistent with both galaxies having non-solar chemical mixtures. For comparison, the M32 data is consistent with a chemical enrichment history like that in the Galactic disk; M32 could not have formed from the stripping of a larger elliptical galaxy. The behaviour of the near-infrared line indices as a function of radius is also investigated. The radial gradients that are present in NGC 4486B and NGC 5846A at large radii break down or reverse within the central few tenths of an arcsec. Evidence is presented that the nuclear regions of NGC 4486B and NGC 5846A harbour intermediate age populations.

arXiv commentAccepted for publication in the Astrophysical Journal

References in corpus (32)

• The Demography of Massive Dark Objects in Galaxy Centres
• Evolutionary population synthesis: models, analysis of the ingredients and application to high-z galaxies
• The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances
• The Centers of Early-Type Galaxies with HST. IV. Central Parameter Relations
• The Stellar Population Histories of Local Early-Type Galaxies. I. Population Parameters
• The ACS Virgo Cluster Survey. VI. Isophotal Analysis and the Structure of Early-Type Galaxies
• The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
• GRAPE-SPH Chemodynamical Simulation of Elliptical Galaxies I: Evolution of Metallicity Gradients
• M32+/-1
• Stellar populations of early-type galaxies in different environments II. Ages and metallicities
• Tidal Interaction of M32 and NGC 205 with M31: Surface Photometry and Numerical Simulations
• The black hole mass distribution in early-type galaxies: cusps in HST photometry interpreted through adiabatic black hole growth
• A new formation model for M32: A threshed early-type spiral?
• Stellar populations of early-type galaxies in different environments I. Line-strength indices
• New Clues on the Calcium Underabundance in Early-Type Galaxies
• Spectroscopic Evidence for a Supermassive Black Hole in NGC 4486B
• Evidence for an outer disk in the Prototype `Compact Elliptical' Galaxy M32
• The NGC 5846 Group: Dynamics and the Luminosity Function to M_R=-12
• Stellar populations of early-type galaxies in different environments III. Line-strength gradients
• A New Approach to the Study of Stellar Populations in Early-Type Galaxies: K-band Spectral Indices and an Application to the Fornax Cluster
• Accretion and nuclear activity of quiescent supermassive black holes. I: X-ray study
• Accretion and nuclear activity of quiescent supermassive black holes. II: optical study and interpretation
• Radial Age and Metal Abundance Gradients in the Stellar Content of M32
• Balmer and Metal Absorption Feature Gradients in M32
• The Nuclear Dynamics of M32. I. Data and Stellar Kinematics
• Discovery of two M32 twins in Abell 1689
• Discovery of a new M32-like "Compact Elliptical" galaxy in the halo of the Abell 496 cD galaxy
• High surface brightness dwarf galaxies in the Fornax cluster
• The Evolved Red Stellar Content of M32
• A detailed two-dimensional stellar population study of M32
• New Evolutionary Synthesis code. An application to the irregular galaxy NGC 1560
• The Brightest Stars in M32: Comparing Predictions from Spectra with the Resolved Stellar Content

Cited by in corpus (17)

• SDSSJ150634.27+013331.6: the second compact elliptical galaxy in the NGC5846 group
• A review of elliptical and disc galaxy structure, and modern scaling laws
• Dynamical versus Stellar Masses of Ultracompact Dwarf Galaxies in the Fornax Cluster
• The HST/ACS Coma Cluster Survey: V - Compact Stellar Systems in the Coma Cluster
• A 3.5-million Solar Masses Black Hole in the Centre of the Ultracompact Dwarf Galaxy Fornax UCD3
• The AIMSS Project III: The Stellar Populations of Compact Stellar Systems
• Deep Chandra Observations of Edges and Bubbles in the NGC 5846 Galaxy Group
• A new stellar library in the region of the CO index at 2.3 $\mu$m. New index definition and empirical fitting functions
• Tidal streams in newly discovered M32 analogues: evidence for the stripping scenario
• Kinetys II: Constraints on spatial variations of the stellar initial mass function from K-band spectroscopy
• Early-type galaxies in the near-infrared: 1.5-2.4\mum spectroscopy
• Integrated K-band spectra of old and intermediate-age globular clusters in the Large Magellanic Cloud
• Gas Accretion in the M32 Nucleus: Past & Present
• Strong CO Absorption Features in Massive ETGs
• Surprisingly Strong K-band Emission Found in Low Luminosity Active Galactic Nuclei
• Seeing Red in M32: Constraints on the Stellar Content from Near- and Mid-Infrared Observations and Applications for Studies of More Distant Galaxies
• Resolved nuclear kinematics link the formation and growth of nuclear star clusters with the evolution of their early and late-type hosts