Testing Verlinde's emergent gravity in early-type galaxies
Date Issued
2018
Author(s)
Abstract
Emergent Gravity (EG) has been proposed to resolve the missing mass problem in galaxies, replacing the potential of dark matter (DM) by the effect of the entropy displacement of dark energy by baryonic matter. This apparent DM depends only on the baryonic mass distribution and the present-day value of the Hubble parameter. In this paper we test the EG proposition, formalized by Verlinde for a spherical and isolated mass distribution using the central dynamics (Sloan Digital Sky Survey velocity dispersion, σ) and the K-band light distribution in a sample of 4032 massive (M_{\star }≳ 10^{10} M_{☉}) and local early-type galaxies (ETGs) from the SPIDER datasample. Our results remain unaltered if we consider the sample of 750 roundest field galaxies. Using these observations we derive the predictions by EG for the stellar mass-to-light ratio (M/L) and the initial mass function (IMF). We demonstrate that, consistently with a classical Newtonian framework with a DM halo component or alternative theories of gravity as MOdified Newtonian Dynamics (MOND), the central dynamics can be fitted if the IMF is assumed non-universal and systematically changing with σ. For the case of EG, we find lower, but still acceptable, stellar M/L if compared with the DM-based Navarro, Frenk & White (NFW) model and with MOND, but pretty similar to adiabatically contracted DM haloes and with expectations from spectral gravity-sensitive features. If the strain caused by the entropy displacement would be not maximal, as adopted in the current formulation, then the dynamics of ETGs could be reproduced with larger M/L.
Volume
473
Issue
2
Start page
2324
Issn Identifier
0035-8711
Ads BibCode
2018MNRAS.473.2324T
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
Tortora+18_MNRAS_473_2324.pdf
Description
Pdf editoriale
Size
487.19 KB
Format
Adobe PDF
Checksum (MD5)
17e10f35f9b0133fa5429742ea28344f