# SDSS-IV MaNGA: variation of the stellar initial mass function in spiral and early-type galaxies

## TL;DR

This study uses Jeans anisotropic modeling on MaNGA galaxies to explore how the stellar initial mass function varies with galaxy type and velocity dispersion, confirming previous findings and highlighting the impact of mass-to-light ratio gradients.

## Contribution

It demonstrates the variation of the IMF in both spiral and early-type galaxies using JAM and compares it with stellar population synthesis estimates, extending previous results.

## Key findings

- Lower velocity dispersion early-type galaxies have a Chabrier-like IMF.
- Higher velocity dispersion galaxies show a more bottom-heavy IMF.
- Considering mass-to-light ratio gradients strengthens the observed IMF trends.

## Abstract

We perform Jeans anisotropic modeling (JAM) on elliptical and spiral galaxies from the MaNGA DR13 sample. By comparing the stellar mass-to-light ratios estimated from stellar population synthesis (SPS) and from JAM, we find a similar systematic variation of the initial mass function (IMF) as in the earlier $\rm ATLAS^{3D}$ results. Early type galaxies (elliptical and lenticular) with lower velocity dispersions within one effective radius are consistent with a Chabrier-like IMF while galaxies with higher velocity dispersions are consistent with a more bottom heavy IMF such as the Salpeter IMF. Spiral galaxies have similar systematic IMF variations, but with slightly different slopes and larger scatters, due to the uncertainties caused by higher gas fractions and extinctions for these galaxies. Furthermore, we examine the effects of stellar mass-to-light ratio gradients on our JAM modeling, and find that the trends from our results becomes stronger after considering the gradients.