Abundance ratios and IMF slope in the dwarf elliptical galaxy NGC~1396 with MUSE

Abstract

Deep observations of the dwarf elliptical (dE) galaxy NGC 1396 (M${}_V=-16.60$, Mass $\sim 4\times 10^8$ M${}_{\odot }$), located in the Fornax cluster, have been performed with the VLT/ MUSE spectrograph in the wavelength region from $4750-9350$ Å. In this paper we present a stellar population analysis studying chemical abundances, the star formation history (SFH) and the stellar initial mass function (IMF) as a function of galacto-centric distance. Different, independent ways to analyse the stellar populations result in a luminosity-weighted age of $\sim$ 6 Gyr and a metallicity [Fe/H]$\sim$ $-0.4$, similar to other dEs of similar mass. We find unusually overabundant values of [Ca/Fe] $\sim +0.1$, and under-abundant Sodium, with [Na/Fe] values around $-0.1$, while [Mg/Fe] is overabundant at all radii, increasing from $\sim +0.1$ in the centre to $\sim +0.2$ dex. We notice a significant metallicity and age gradient within this dwarf galaxy. To constrain the stellar IMF of NGC 1396, we find that the IMF of NGC 1396 is consistent with either a Kroupa-like or a top-heavy distribution, while a bottom-heavy IMF is firmly ruled out. An analysis of the abundance ratios, and a comparison with galaxies in the Local Group, shows that the chemical enrichment history of NGC 1396 is similar to the Galactic disc, with an extended star formation history. This would be the case if the galaxy originated from a LMC-sized dwarf galaxy progenitor, which would lose its gas while falling into the Fornax cluster.

arXiv comment21 pages, 17 figures

References in corpus (106)

• On the variation of the Initial Mass Function
• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• MILES: A Medium resolution INT Library of Empirical Spectra
• Adaptive spatial binning of integral-field spectroscopic data using Voronoi tessellations
• Star Formation Histories, Abundances and Kinematics of Dwarf Galaxies in the Local Group
• Environmental Effects on Late-Type Galaxies in Nearby Clusters
• Galactic chemical evolution: Carbon through Zinc
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• An updated MILES stellar library and stellar population models
• Stellar Chemical Signatures And Hierarchical Galaxy Formation
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• On the shape of the light profiles of early-type galaxies
• The Indo-U.S. Library of Coude Feed Stellar Spectra
• The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
• The ACS Fornax Cluster Survey. V. Measurement and Recalibration of Surface Brightness Fluctuations and a Precise Value of the Fornax--Virgo Relative Distance
• A Substantial Population of Low Mass Stars in Luminous Elliptical Galaxies
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. II. Results
• A Stellar Mass Threshold for Quenching of Field Galaxies
• A new chemo-evolutionary population synthesis model for early-type galaxies. I: Theoretical basis
• Evolutionary stellar population synthesis with MILES - II. Scaled-solar and α-enhanced models
• Fitting the integrated Spectral Energy Distributions of Galaxies
• Empirical calibration of the near-IR Ca II triplet - I. The stellar library and index definition
• Properties of Early-Type, Dry Galaxy Mergers and the Origin of Massive Elliptical Galaxies
• The Distribution Of Heavy Elements In Spiral And Elliptical Galaxies
• Dwarf Elliptical Galaxies
• MIUSCAT: extended MILES spectral coverage. I. Stellar populations synthesis models
• GRAPE-SPH Chemodynamical Simulation of Elliptical Galaxies I: Evolution of Metallicity Gradients
• On the typical timescale for the chemical enrichment from SNeIa in Galaxies
• SPIDER VIII - Constraints on the Stellar Initial Mass Function of Early-type Galaxies from a Variety of Spectral Features
• Early-Type Galaxy Archeology: Ages, Abundance Ratios, and Effective Temperatures from Full-Spectrum Fitting
• Counting Low-Mass Stars in Integrated Light
• A high resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
• Systematic variation of the stellar Initial Mass Function with velocity dispersion in early-type galaxies
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. III. Subpopulations: distributions, shapes, origins
• Stellar populations of early-type galaxies in different environments II. Ages and metallicities
• A new chemo-evolutionary population synthesis model for early-type galaxies. II: Observations and Results
• A new library of theoretical stellar spectra with scaled-solar and alpha-enhanced mixtures
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. I. On the possible disk nature of bright early-type dwarfs
• The globular cluster system of NGC 1399 V. dynamics of the cluster system out to 80 kpc
• Evidence For A Mild Steepening And Bottom-Heavy IMF In Massive Galaxies From Sodium And Titanium-Oxide Indicators
• Nuclear star clusters in 228 spiral galaxies in the HST/WFPC2 archive: catalogue and comparison to other stellar systems
• The stellar IMF determined in early-type galaxies from a non-degenerate set of optical line indices
• Near-IR line-strengths in elliptical galaxies: evidence for IMF variations?
• The ACS Fornax Cluster Survey. I. Introduction to the Survey and Data Reduction Procedures
• Spectroscopy of Red Giants in the LMC Bar: Abundances, Kinematics, and the Age-Metallicity Relation
• Multi-Element Abundance Measurements from Medium-Resolution Spectra. I. The Sculptor Dwarf Spheroidal Galaxy
• Chemical abundances in LMC stellar populations I. The Inner disk sample Based on observations collected at the VLT UT2 telescope
• Calcium II Triplet Spectroscopy of LMC Red Giants. I. Abundances and Velocities for a Sample of Populous Clusters
• Age and metallicity gradients in early-type galaxies: A dwarf to giant sequence
• The ACS Fornax Cluster Survey. VI. The Nuclei of Early-Type Galaxies in the Fornax Cluster
• Formation and Evolution of Dwarf Elliptical Galaxies - II. Spatially resolved star-formation histories
• Stellar populations of early-type galaxies in different environments I. Line-strength indices
• The evolution and star formation of dwarf galaxies in the Fornax Cluster
• On the survival of metallicity gradients to major dry-mergers
• New Clues on the Calcium Underabundance in Early-Type Galaxies
• The mass-metallicity gradient relation of early-type galaxies
• Evolution of dwarf early-type galaxies I. Spatially resolved stellar populations and internal kinematics of Virgo cluster dE/dS0 galaxies
• Dynamical masses of ultra-compact dwarf galaxies in Fornax
• The stellar accretion origin of stellar population gradients in massive galaxies at large radii
• The Stellar Initial Mass Function in Early-Type Galaxies From Absorption Line Spectroscopy. I. Data and Empirical Trends
• Stellar Populations of Dwarf Elliptical Galaxies: UBVRI Photometry of Dwarf Elliptical Galaxies in the Virgo Cluster
• Radial constraints on the Initial Mass Function from TiO features and Wing-Ford band in Early-type Galaxies
• The relation between stellar populations, structure and environment for dwarf elliptical galaxies from the MAGPOP-ITP
• Dynamical Versus Stellar Masses in Compact Early-Type Galaxies: Further Evidence for Systematic Variation in the Stellar Initial Mass Function
• The Cluster Velocity Dispersion of the Abell 2199 cD Halo of NGC 6166
• The puzzlingly small CaII triplet absorption in elliptical galaxies
• Nuclei of early-type dwarf galaxies: insights from stellar populations
• An optimized H_βindex for disentangling stellar population ages
• A near-infrared census of the multi-component stellar structure of early-type dwarf galaxies in the Virgo cluster
• Simulations of the formation and evolution of isolated dwarf galaxies
• First Stellar Abundances in the Dwarf Irregular Galaxy Sextans A
• The SAURON Project - XIX. Optical and near-infrared scaling relations of nearby elliptical, lenticular and Sa galaxies
• Ultrafaint Dwarf Galaxies - the lowest mass relics from before reionization
• The Next Generation Virgo Cluster Survey. XII. Stellar Populations and Kinematics of Compact, Low-Mass Early-Type Galaxies from Gemini GMOS-IFU Spectroscopy
• MILES extended: Stellar population synthesis models from the optical to the infrared
• The Extended Spatial Distribution of Globular Clusters in the Core of the Fornax Cluster
• Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. IV. The Large Magellanic Cloud: $\alpha$, Fe-peak, Light, and Heavy Elements
• The Chemical Properties of Milky Way and M31 Globular Clusters: II. Stellar Population Model Predictions
• Virgo Cluster and field dwarf ellipticals in 3D: I. On the variety of stellar kinematic and line-strength properties
• The puzzlingly large Ca II triplet absorption in dwarf elliptical galaxies
• Balmer and Metal Absorption Feature Gradients in M32
• Midlife Crises in Dwarf Galaxies in the NGC 5353/4 Group
• Abundance patterns in early-type galaxies: is there a 'knee' in the [Fe/H] vs. [alpha/Fe] relation?
• Stellar orbits and the survival of metallicity gradients in simulated dwarf galaxies
• The HST/ACS Coma Cluster Survey: VII - Colour Gradients in Giant and Dwarf Early-Type Galaxies
• Stellar Kinematics and Structural Properties of Virgo Cluster Dwarf Early-Type Galaxies from the SMAKCED Project. I. Kinematically Decoupled Cores and Implications for Infallen Groups in Clusters
• The IMF-sensitive 1.14-micron Na I doublet in early-type galaxies
• The Stellar Haloes of Massive Elliptical Galaxies III: Kinematics at Large Radius
• IC 225: a dwarf elliptical galaxy with a peculiar blue core
• Recovering star formation histories: Integrated-light analyses vs stellar colour-magnitude diagrams
• Ca, Fe, and Mg Trends Among and Within Elliptical Galaxies
• The near-IR Ca II triplet - sigma relation for bulges of spiral galaxies
• The central region of the Fornax cluster -- I. A catalog and photometric properties of galaxies in selected CCD fields
• The initial mass functions of M31 and M32 through far red stellar absorption features
• Towards a Solution for the Ca II Triplet Puzzle : Results from Dwarf Elliptical Galaxies
• Color-Magnitude Relations of Early-type Dwarf Galaxies in the Virgo Cluster: An Ultraviolet Perspective
• Virgo cluster and field dwarf ellipticals in 3D: III. Spatially and temporally resolved stellar populations
• How the first stars shaped the faintest gas-dominated dwarf galaxies
• Dark Matter and IMF normalization in Virgo dwarf early-type galaxies
• Metallicity Gradients - Mass Dependency in Dwarf Elliptical Galaxies
• FCC046: a candidate gaseous polar ring dwarf elliptical galaxy in the Fornax Cluster
• The Integrated Calcium II Triplet as a Metallicity Indicator: Comparisons with High Resolution [Fe/H] in M31 Globular Clusters
• A continuum of structure and stellar content from Virgo cluster early-type dwarfs to giants?
• The impact of accurate distances to dwarf elliptical galaxies on cosmology
• Kinematics and Angular Momentum in Early Type Galaxy Halos

Cited by in corpus (32)

• The Next Generation Fornax Survey (NGFS): II. The Central Dwarf Galaxy Population
• MUSE observations of M87: radial gradients for the stellar initial-mass function and the abundance of Sodium
• The Fornax3D project: overall goals, galaxy sample, MUSE data analysis and initial results
• An EAGLE's View of Ex-situ Galaxy Growth
• Revealing the intermediate-mass black hole at the heart of the dwarf galaxy NGC 404 with sub-parsec resolution ALMA observations
• Combining Stellar Populations with Orbit-Superposition Dynamical Modelling - the Formation History of the Lenticular Galaxy NGC 3115
• Virgo Redux: The Masses and Stellar Content of Nuclei in Early-Type Galaxies from Multi-Band Photometry and Spectroscopy
• VEGAS-SSS II: Comparing the globular cluster systems in NGC3115 and NGC1399 using VEGAS and FDS survey data
• Comparison of Stellar Population Model Predictions Using Optical and Infrared Spectroscopy
• The Fornax Cluster VLT Spectroscopic Survey. I - VIMOS spectroscopy of compact stellar systems in the Fornax core region
• The Fornax Deep Survey with VST. IX. The catalog of sources in the FDS area, with an example study for globular clusters and background galaxies
• The stellar population and initial mass function of NGC 1399 with MUSE
• A spectroscopic census of the Fornax cluster and beyond: preparing for next generation surveys
• The SAMI -- Fornax Dwarfs Survey I: Sample, observations and the specific stellar angular momentum of dwarf elliptical galaxies
• The Next Generation Fornax Survey (NGFS): VII. A MUSE view of the nuclear star clusters in Fornax dwarf galaxies
• Evolution of the Stellar Mass-Metallicity Relation. II. Constraints on Galactic Outflows from the Mg Abundances of Quiescent Galaxies
• On the accretion of a new group of galaxies onto Virgo: I. Internal kinematics of nine in-falling dEs
• The SAMI-Fornax Dwarfs Survey III: Evolution of [$\alpha$/Fe] in dwarfs, from Galaxy Clusters to the Local Group
• Merger histories of brightest group galaxies from MUSE stellar kinematics
• Mapping Accreted Stars in Early-Type Galaxies Across the Mass-Size Plane
• The SAMI -- Fornax Dwarfs Survey II: The Stellar Mass Fundamental Plane and the Dark Matter fraction of Dwarf Galaxies
• Spatially-resolved chemodynamics of the starburst dwarf galaxy CGCG 007-025: Evidence for recent accretion of metal-poor gas
• Exploring the AGN-Merger Connection in Arp 245 I: Nuclear Star Formation and Gas Outflow in NGC 2992
• The hELENa project - II. Abundance distribution trends of early-type galaxies: from dwarfs to giants
• Abundance ratios in dwarf elliptical galaxies
• Stellar populations in local AGNs: evidence for enhanced star formation in the inner 100pc
• The MAGPI Survey: Impact of environment on the total internal mass distribution of galaxies in the last 5 Gyr
• Colors of Dwarf Ellipticals from GALEX to WISE
• Transverse clues on the kpc-scale structure of the circumgalactic medium as traced by C IV absorption
• The Next Generation Fornax Survey (NGFS): V. Discovery of a dwarf-dwarf galaxy pair at z=0.30 and its characterization using deep VLT/MUSE observations
• Star-forming Galaxies in Intermediate Redshift Clusters: Stellar vs. Dynamical Masses of Luminous Compact Blue Galaxies
• NGC 147 Corroborates the Break in the Stellar Mass-Stellar Metallicity Relation for Galaxies