The half mass radius of MaNGA galaxies: Effect of IMF gradients

Abstract

Gradients in the stellar populations (SP) of galaxies -- e.g., in age, metallicity, stellar Initial Mass Function (IMF) -- can result in gradients in the stellar mass to light ratio, $M_{\ast }/L$. Such gradients imply that the distribution of the stellar mass and light are different. For old SPs, e.g., in early-type galaxies at $z\sim 0$, the $M_{\ast }/L$ gradients are weak if driven by variations in age and metallicity, but significantly larger if driven by the IMF. A gradient which has larger $M_{\ast }/L$ in the center increases the estimated total stellar mass ($M_{\ast }$) and reduces the scale which contains half this mass ($R_{e,\ast }$), compared to when the gradient is ignored. For the IMF gradients inferred from fitting MILES simple SP models to the H${}_{\beta }$, $⟨$Fe$⟩$, [MgFe] and TiO${}_{2SDSS}$ absorption lines measured in spatially resolved spectra of early-type galaxies in the MaNGA survey, the fractional change in $R_{e,\ast }$ can be significantly larger than that in $M_{\ast }$, especially when the light is more centrally concentrated. The $R_{e,\ast }-M_{\ast }$ correlation which results is offset by 0.3 dex to smaller sizes compared to when these gradients are ignored. Comparisons with `quiescent' galaxies at higher-$z$ must account for evolution in SP gradients (especially age and IMF) and the light profile before drawing conclusions about how $R_{e,\ast }$ and $M_{\ast }$ evolve. The implied merging between higher-$z$ and the present is less contrived if $R_{e,\ast }/R_e$ at $z\sim 0$ is closer to our IMF-driven gradient calibration than to unity.

16 pages, 15 figures, accepted for publication in MNRAS

References in corpus (26)

• 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
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• The SAURON project -- IX. A kinematic classification for early-type galaxies
• The MaNGA Integral Field Unit Fiber Feed System for the Sloan 2.5 m Telescope
• The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey
• Size evolution of the most massive galaxies at 1.7<z<3 from GOODS NICMOS survey imaging
• 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
• Radial variations in the stellar initial mass function of early-type galaxies
• 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
• The mass-metallicity gradient relation of early-type galaxies
• SDSS-IV DR17: Final Release of MaNGA PyMorph Photometric and Deep Learning Morphological Catalogs
• The stellar accretion origin of stellar population gradients in massive galaxies at large radii
• Timing the formation and assembly of early-type galaxies via spatially resolved stellar populations analysis
• IMF and [Na/Fe] abundance ratios from optical and NIR Spectral Features in Early-type Galaxies
• The kinematics of massive quiescent galaxies at $1.4<z<2.1$: dark matter fractions, IMF variation, and the relation to local early-type galaxies
• The SAMI Galaxy Survey: stellar population gradients of central galaxies
• The Fundamental Plane in the LEGA-C Survey: unraveling the $M/L$ variations of massive star-forming and quiescent galaxies at $z\sim 0.8$
• Galaxy properties as revealed by MaNGA. III. Kinematic profiles and stellar population gradients in S0s
• 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
• The evolution of compact massive quiescent and starforming galaxies derived from the $R_e-R_h$ and $M_{\mathrm{star}}-M_h$ relations
• Wolf-Rayet galaxies in SDSS-IV MaNGA. II. Metallicity dependence of the high-mass slope of the stellar initial mass function
• When did the initial mass function become bottom-heavy?

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