We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities and stellar masses of 100 UDGs distributed in an area of ∼330 deg2 in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosity-weighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population scaling relations that show that UDGs are, as a population, similar to other low-surface brightness galaxies.
@article{arxiv.2002.05171,
title = {One hundred SMUDGes in S-PLUS: ultra-diffuse galaxies flourish in the field},
author = {C. E. Barbosa and D. Zaritsky and R. Donnerstein and H. Zhang and A. Dey and C. Mendes de Oliveira and L. Sampedro and A. Molino and M. V. Costa-Duarte and P. Coelho and A. Cortesi and F. R. Herpich and J. A. Hernandez-Jimenez and T. Santos-Silva and E. Pereira and A. Werle and R. A. Overzier and R. Cid Fernandes and A. V. Smith Castelli and T. Ribeiro and W. Schoenell and A. Kanaan},
journal= {arXiv preprint arXiv:2002.05171},
year = {2020}
}
Comments
24 pages, 10 figures, accepted for Publication in ApJS