GHASP: an H$\alpha$ kinematical survey of spiral galaxies -- XIII. Distribution of luminous and dark matter in spiral and irregular nearby galaxies using H$\alpha$ and HI rotation curves and WISE photometry

TL;DR

This study models the distribution of luminous and dark matter in 31 nearby spiral and irregular galaxies using combined H$ extalpha$ and HI rotation curves along with WISE photometry, comparing different halo profiles and data sets.

Contribution

It provides a comprehensive analysis of dark matter halo properties using hybrid rotation curves and assesses the impact of including neutral gas and different data sources on mass modeling.

Findings

Hybrid rotation curves yield more consistent mass models.

ISO profiles fit the rotation curves better than NFW profiles.

Including HI gas affects the derived halo parameters.

Abstract

We present the mass models of 31 spiral and irregular nearby galaxies obtained using hybrid rotation curves (RCs) combining high resolution GHASP Fabry-Perot H$\alpha$ RCs and extended WHISP HI ones together with 3.4 $\mu$m WISE photometry. The aim is to compare the dark matter (DM) halo properties within the optical radius using only H$\alpha$ RCs with the effect of including and excluding the mass contribution of the neutral gas component, and when using HI or hybrid RCs. Pseudo-isothermal (ISO) core and Navarro-Frenk-White (NFW) cuspy DM halo profiles are used with various fiducial fitting procedures. Mass models using H$\alpha$ RCs including or excluding the HI gas component provide compatible disc M/L. The correlations between DM halo and baryon parameters do not strongly depend on the RC. Clearly, the differences between the fitting procedures are larger than between the different datasets. Hybrid and HI RCs lead to higher M/L values for both ISO and NFW best fit models but lower central densities for ISO halos and higher concentration for NFW halos than when using H$\alpha$ RCs only. The agreement with the mass model parameters deduced using hybrid RCs, considered as a reference, is better for HI than for H$\alpha$ RCs. ISO density profiles better fit the RCs than the NFW ones, especially when using H$\alpha$ or hybrid RCs. Halo masses at the optical radius determined using the various datasets are compatible even if they tend to be overestimated with H$\alpha$ RCs. Hybrid RCs are thus ideal to study the mass distribution within the optical radius.