- 'P. Coelho'
- 'A. Cortesi'
- 'F. R. Herpich'
- 'J. A. Hernandez-Jimenez'
- 'T. Santos-Silva'
- 'E. Pereira'
- 'A. Werle'
- 'R. A. Overzier'
- 'R. Cid Fernandes'
- 'A. V. Smith Castelli'
- 'T. Ribeiro'
- 'W. Schoenell'
- 'A. Kanaan'
bibliography:
- 'smudges-splus.bib'
title: 'One hundred SMUDGes in S-PLUS: ultra-diffuse galaxies flourish in the field'
---

Introduction {#sec:intro}
============

are a recently defined class of galaxy initially found in large numbers in the Coma Cluster [@2015ApJ...798L..45V]. Their unusually large half-light radii, $R_e\ge 1.5$ kpc, for galaxies with such low central surface brightness, $\mu_{0,g}\ge 24$ mag arcsec$^{-2}$, are striking. Although large LSB galaxies have been known for quite some time [@1976Natur.263..573D; @1984AJ.....89..919S; @1988ApJ...330..634I; @1988AJ.....95.1389S; @1995MNRAS.275..121S; @1997AJ....114..635D; @1997ApJ...482..104S], the current excitement originates from indications, either from kinematic measures of the unresolved light or globular clusters in these galaxies [@2016ApJ...819L..20B; @2018ApJ...856L..31T; @2019ApJ...880...91V], or from the numbers of globular clusters alone [@2016ApJ...822L..31P; @2016ApJ...830...23B; @2017ApJ...844L..11V; @2018ApJ...856L..30V], that at least some lie in massive $(>10^{11}$ M$_\odot$) halos.

The detection of populations of in galaxy clusters led to the exploration of a possible evolutionary link between these galaxies and their harsh environment [@2017ApJ...850...99S; @2018RNAAS...2...43C; @2018MNRAS.480L.106O; @2018ApJ...866L..11B; @2019MNRAS.485..382C]. However, were also found in 