Strong gravitational lensing and the stellar IMF of early-type galaxies

Leier, Dominik; Ferreras, Ignacio; Saha, Prasenjit; Charlot, S.; Bruzual, G.; Barbera, F. La

doi:10.1093/mnras/stw885

Cited by 58 publications

(56 citation statements)

References 78 publications

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“…Figures (8) to (11) indicate that for low and moderate black hole masses and SFRs, the total masses of the most luminous ETGs are with the IGIMF a factor of 1.5 to 2 higher than expected with the canonical IMF. This is consistent with the difference between mass estimates for ETGs from the canonical IMF and the mass estimates for the same galaxies from gravitational lensing in Leier et al (2016), see their table (3). The fits to the M/LV ratios in Fig.…”

Section: Interpolations Of the Igimf 17supporting

confidence: 88%

Simple interpolation functions for the galaxy-wide stellar initial mass function and its effects in early-type galaxies

Dabringhausen

2019

Monthly Notices of the Royal Astronomical Society

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The galaxy-wide stellar initial mass function (IGIMF) of a galaxy is thought to depend on its star formation rate (SFR). Using a catalogue of observational properties of early-type galaxies (ETGs) and a relation that correlates the formation timescales of ETGs with their stellar masses, the dependencies of the IGIMF on the SFR are translated into dependencies on more intuitive parameters like present-day luminosities in different passbands. It is found that up to a luminosity of approximately 10 9 L ⊙ (quite independent of the considered passband), the total masses of the stellar populations of ETGs are slightly lower than expected from the canonical stellar initial mass function. However, the actual mass of the stellar populations of the most luminous ETGs may be up to two times higher than expected from an SSP-model with the canonical IMF. The variation of the IGIMF with the mass of ETGs are presented here also as convenient functions of the luminosity in various passbands.

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Section: Interpolations Of the Igimf 17supporting

confidence: 88%

Simple interpolation functions for the galaxy-wide stellar initial mass function and its effects in early-type galaxies

Dabringhausen

2019

Monthly Notices of the Royal Astronomical Society

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“…The values we derived for NGC 7113 and PGC 67207 are compared to those of ETGs in the SLACS ) and ATLAS3D (Cappellari et al 2013) surveys and in the Coma (Thomas et al 2007 and Abell 262 (Wegner et al 2012) clusters. The results for the ETGs studied by Spiniello et al (2014), Conroy & van Dokkum (2012), Tortora et al (2013), Posacki et al (2015), Smith, Lucey, & Conroy (2015), and Leier et al (2016) are also shown. In both the galaxies we analysed the dynamical mass following the light exceeds the Kroupa value by far (Υ * ,dyn /Υ * ,Kroupa 2).…”

Section: Discussionmentioning

confidence: 79%

The density of dark matter haloes of early-type galaxies in low-density environments

Corsini

Wegner

Thomas

et al. 2016

Mon. Not. R. Astron. Soc.

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New photometric and long-slit spectroscopic observations are presented for NGC 7113, PGC 1852, and PGC 67207 which are three bright galaxies residing in low-density environments. The surface-brightness distribution is analysed from the K S -band images taken with adaptive optics at the Gemini North Telescope and the ugriz-band images from the Sloan Digital Sky Survey while the line-of-sight stellar velocity distribution and line-strength Lick indices inside the effective radius are measured along several position angles. The age, metallicity, and α-element abundance of the galaxies are estimated from single stellar-population models. In spite of the available morphological classification, images show that PGC 1852 is a barred spiral which we do not further consider for mass modelling. The structural parameters of the two early-type galaxies NGC 7113 and PGC 67207 are obtained from a two-dimensional photometric decomposition and the mass-to-light ratio of all the (luminous and dark) mass that follows the light is derived from orbit-based axisymmetric dynamical modelling together with the mass density of the dark matter halo. The dynamically derived mass that follows the light is about a factor of 2 larger than the stellar mass derived using stellar-population models with Kroupa initial mass function. Both galaxies have a lower content of halo dark matter with respect to early-type galaxies in high-density environments and in agreement with the predictions of semi-analytical models of galaxy formation.

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“…Constraints on the IMF have been achieved on two fronts, namely via estimates of the stellar M/L through dynamical (see, e.g., Cappellari et al 2012Cappellari et al , 2013 or lensing analyses (see, e.g., Treu et al 2010; ⋆ E-mail: labarber@na.astro.it Leier et al 2015); or via targeted spectral features sensitive to the presence of low-mass stars, which in effect constrain the relative contribution of dwarf versus giant stars (see, e.g., Cenarro et al 2003;van Dokkum & Conroy 2010;Ferreras et al 2013;La Barbera et al 2013;Spiniello et al 2014). These two approaches are affected by different systematics, but both agree in that the stellar populations found in the more massive ETGs appear to have formed from a (bottom-)heavier IMF than the standard one (see, e.g., Kroupa 2001;Chabrier 2003).…”

Section: Introductionmentioning

confidence: 99%

IMF and [Na/Fe] abundance ratios from optical and NIR spectral features in early-type galaxies

Barbera

Vazdekis

Ferreras

et al. 2016

Mon. Not. R. Astron. Soc.

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We present a joint analysis of the four most prominent sodium-sensitive features (Na D, Na I λ8190Å, Na I λ1.14µm, and Na I λ2.21µm), in the optical and Near-Infrared spectral range, of two nearby, massive (σ ∼ 300 km s −1 ), early-type galaxies (named XSG1 and XSG2). Our analysis relies on deep VLT/X-Shooter long-slit spectra, along with newly developed stellar population models, allowing for [Na/Fe] variations, up to ∼1.2 dex, over a wide range of age, total metallicity, and IMF slope. The new models show that the response of the Na-dependent spectral indices to [Na/Fe] is stronger when the IMF is bottom heavier. For the first time, we are able to match all four Na features in the central regions of massive early-type galaxies, finding an overabundance of [Na/Fe], in the range 0.5-0.7 dex, and a bottom-heavy IMF. Therefore, individual abundance variations cannot be fully responsible for the trends of gravity-sensitive indices, strengthening the case towards a non-universal IMF. Given current limitations of theoretical atmosphere models, our [Na/Fe] estimates should be taken as upper limits. For XSG1, where line strengths are measured out to ∼0.8R e , the radial trend of [Na/Fe] is similar to [α/Fe] and [C/Fe], being constant out to ∼0.5R e , and decreasing by ∼0.2-0.3 dex at ∼0.8R e , without any clear correlation with local metallicity. Such a result seems to be in contrast with the predicted increase of Na nucleosynthetic yields from AGB stars and Type II SNe. For XSG1, the Na-inferred IMF radial profile is consistent, within the errors, with that derived from TiO features and the Wing-Ford band, presented in a recent paper.

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Strong gravitational lensing and the stellar IMF of early-type galaxies

Cited by 58 publications

References 78 publications

Simple interpolation functions for the galaxy-wide stellar initial mass function and its effects in early-type galaxies

Simple interpolation functions for the galaxy-wide stellar initial mass function and its effects in early-type galaxies

The density of dark matter haloes of early-type galaxies in low-density environments

IMF and [Na/Fe] abundance ratios from optical and NIR spectral features in early-type galaxies

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