IMF shape constraints from stellar populations and dynamics from CALIFA

Abstract

In this letter we describe how we use stellar dynamics information to constrain the shape of the stellar IMF in a sample of 27 early-type galaxies from the CALIFA survey. We obtain dynamical and stellar mass-to-light ratios, Υ dyn and Υ * , over a homogenous aperture of 0.5 R e . We use the constraint Υ dyn ≥Υ * to test two IMF shapes within the framework of the extended MILES stellar population models. We rule out a single power law IMF shape for 75% of the galaxies in our sample. Conversely, we find that a double power law IMF shape with a varying high-mass end slope is compatible (within 1σ) with 95% of the galaxies. We also show that dynamical and stellar IMF mismatch factors give consistent results for the systematic variation of the IMF in these galaxies.

A counter-image to the gravitational arc in Abell 1201:Evidence for IMF variations, or a 10 10 M ⊙ black hole?

“…α = 1.5-2.0 from Conroy & van Dokkum (2012b). However, direct comparisons of these results to M/L measurements are hampered by the unknown detailed shape of the IMF at very low mass (Lyubenova et al 2016). …”

The last 6 Gyr of dark matter assembly in massive galaxies from the Kilo Degree Survey

“…The IMF has been initially considered as universal across galaxy types and cosmic time, mostly because of a lack of evidence of variations among stellar clusters and OB associations in the Milky Way (see Bastian et al 2010 for a review about IMF studies). This assumption has been recently questioned by different dynamical, lensing, and stellar population studies, finding evidence for systematic IMF variations in ETGs Thomas et al 2011;Conroy & van Dokkum 2012;Cappellari et al 2012Cappellari et al , 2013Spiniello et al 2012;Wegner et al 2012;Dutton et al 2013;Ferreras et al 2013;Goudfrooij & Kruijssen 2013;La Barbera et al 2013;Tortora et al 2013;Weidner et al 2013;Goudfrooij & Kruijssen 2014;Shu et al 2015;Tortora et al 2014a,c;Martín-Navarro et al 2015;Lyubenova et al 2016;Tortora et al 2016;Corsini et al 2017;Li et al 2017;Sonnenfeld et al 2017).…”

“…The scenario is even more complicated if one takes into account the effect of a non universal IMF (van Dokkum & Conroy 2010;Treu et al 2010;Thomas et al 2011;Conroy & van Dokkum 2012;Cappellari et al 2012Cappellari et al , 2013Spiniello et al 2012;Wegner et al 2012;Barnabè et al 2013;Dutton et al 2013;Ferreras et al 2013;Goudfrooij & Kruijssen 2013;La Barbera et al 2013;Tortora et al 2013;Weidner et al 2013;Goudfrooij & Kruijssen 2014;Shu et al 2015;McDermid et al 2014;Tortora et al 2014a,c;Martín-Navarro et al 2015;Spiniello et al 2015;Lyubenova et al 2016;Tortora et al 2016;Corsini et al 2017;Li et al 2017;Sonnenfeld et al 2017;Tortora et al 2017). Indeed, the IMF remains the largest source of uncertainty to quantify the stellar and DM mass budget in the central galactic regions.…”

The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints

“…Such comparisons depend on the data set and methods used; Lyubenova et al (2016) found a stronger correlation between total dynamical mass and SPS-based mass.…”