Stellar population analysis of MaNGA early-type galaxies: IMF dependence and systematic effects

Abstract

We study systematics associated with estimating simple stellar population (SSP) parameters -- age, metallicity [M/H], $\alpha$-enhancement [$\alpha$/Fe] and IMF shape -- and associated $M_{\ast }/L$ gradients, of elliptical slow rotators (E-SRs), fast rotators (E-FRs) and S0s from stacked spectra of galaxies in the MaNGA survey. These systematics arise from (i) how one normalizes the spectra when stacking; (ii) having to subtract emission before estimating absorption line strengths; (iii) the decision to fit the whole spectrum or just a few absorption lines; (iv) SSP model differences (e.g. isochrones, enrichment, IMF). The MILES+Padova SSP models, fit to the H${}_{\beta }$, $⟨$Fe$⟩$, TiO${}_{2SDSS}$ and [MgFe] Lick indices in the stacks, indicate that out to the half-light radius $R_e$: (a) ages are younger and [$\alpha$/Fe] values are lower in the central regions but the opposite is true of [M/H]; (b) the IMF is more bottom-heavy in the center, but is close to Kroupa beyond about $R_e/2$; (c) this makes $M_{\ast }/L$ about $2\times$ larger in the central regions than beyond $R_e/2$. While the models of Conroy et al. (2018) return similar [M/H] and [$\alpha$/Fe] profiles, the age and (hence) $M_{\ast }/L$ profiles can differ significantly even for solar abundances and a Kroupa IMF; different responses to non-solar abundances and IMF parametrization further compound these differences. There are clear (model independent) differences between E-SRs, E-FRs and S0s: younger ages and less enhanced [$\alpha$/Fe] values suggest that E-FRs and S0s are not SSPs, but relaxing this assumption is unlikely to change their inferred $M_{\ast }/L$ gradients significantly.

arXiv comment22 pages, 23 figures, accepted for publication in MNRAS

References in corpus (55)

• The chemical composition of the Sun
• On the variation of the Initial Mass Function
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• The epochs of early-type galaxy formation as a function of environment
• Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
• The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey
• Passively Evolving Early-type Galaxies at 1.4<z<2.5 in the Hubble Ultra Deep Field
• Stellar population models of Lick indices with variable element abundance ratios
• Old Stellar Populations. VI. Absorption-Line Spectra of Galaxy Nuclei and Globular Clusters
• The Stellar Population Histories of Local Early-Type Galaxies. I. Population Parameters
• Structure and Kinematics of Early-Type Galaxies from Integral-Field Spectroscopy
• The MaNGA Integral Field Unit Fiber Feed System for the Sloan 2.5 m Telescope
• The Atlas3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies
• The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey
• The SDSS-IV MaNGA Sample: Design, Optimization, and Usage Considerations
• Evolutionary stellar population synthesis with MILES - II. Scaled-solar and α-enhanced models
• SDSS-IV MaNGA IFS Galaxy Survey --- Survey Design, Execution, and Initial Data Quality
• The Data Analysis Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey: Overview
• The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA Derived Quantities, Data Visualization Tools and Stellar Library
• The SAURON project - XVII. Stellar population analysis of the absorption line strength maps of 48 early-type galaxies
• The CALIFA survey across the Hubble sequence: Spatially resolved stellar population properties 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
• SDSS-IV/MaNGA: Spectrophotometric Calibration Technique
• COSMOS-DASH: The Evolution of the Galaxy Size-Mass Relation Since z~3 from new Wide Field WFC3 Imaging Combined with CANDELS/3DHST
• Flux-calibrated stellar population models of Lick absorption-line indices with variable element abundance ratios
• Radial variations in the stellar initial mass function of early-type galaxies
• Metal-rich, Metal-poor: Updated Stellar Population Models for Old Stellar Systems
• The impact of the metallicity and star formation rate on the time-dependent galaxy-wide stellar initial mass function
• Half-mass radii for ~7,000 galaxies at 1.0 < z < 2.5: most of the evolution in the mass-size relation is due to color gradients
• SDSS-IV MaNGA: Global stellar population and gradients for about 2000 early-type and spiral galaxies on the mass-size plane
• SDSS-IV DR17: Final Release of MaNGA PyMorph Photometric and Deep Learning Morphological Catalogs
• SDSS-IV MaNGA PyMorph Photometric and Deep Learning Morphological Catalogs and implications for bulge properties and stellar angular momentum
• SDSS-IV MaNGA: Modeling the Spectral Line Spread Function to Sub-Percent Accuracy
• IMF radial gradients in most massive early-type galaxies
• Sub one percent mass fractions of young stars in red massive galaxies
• SDSS-IV MaNGA: local and global chemical abundance patterns in early-type galaxies
• Galaxy properties as revealed by MaNGA. I. Constraints on Initial Mass Function and M${}_{\ast }$/L gradients in ellipticals
• The stellar population and initial mass function of NGC 1399 with MUSE
• The SAMI Galaxy Survey: stellar population gradients of central galaxies
• Galaxy properties as revealed by MaNGA II. Differences in stellar populations of slow and fast rotator ellipticals and dependence on environment
• $M_{\ast }/L$ gradients driven by IMF variation: Large impact on dynamical stellar mass estimates
• Galaxy properties as revealed by MaNGA. III. Kinematic profiles and stellar population gradients in S0s
• Radial measurements of IMF-sensitive absorption features in two massive ETGs
• SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies
• The Stellar Mass Fundamental Plane: The virial relation and a very thin plane for slow-rotators
• Calibrated, cosmological hydrodynamical simulations with variable IMFs III: Spatially-resolved properties and evolution
• On the Anomalous Balmer Line Strengths in Globular Clusters
• The half mass radius of MaNGA galaxies: Effect of IMF gradients
• Stellar Population and Elemental Abundance Gradients of Early-type Galaxies
• Wolf-Rayet galaxies in SDSS-IV MaNGA. II. Metallicity dependence of the high-mass slope of the stellar initial mass function
• Lessons from the massive relic NGC 1277: remaining in-situ star formation in the cores of massive galaxies
• The Imprint of Element Abundance Patterns on Quiescent Galaxy SEDs
• Optical spectroscopy and initial mass function of $z=0.4$ red galaxies

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