\documentclass{article}
% ========== Packages ==========
\usepackage{graphicx, geometry}
\usepackage{xcolor}
\usepackage{caption}
\usepackage{subcaption}
\usepackage{float}
\usepackage[english]{nomencl}
\makenomenclature
\title{Teste 123}
\begin{document}
\maketitle
\begin{figure}[!ht]
\centering
\caption{Trajectories time development from Fig. \ref{fig:circ_line_traj}}
\begin{subfigure}[t]{0.6\textwidth}
\centering
\caption{}
\includegraphics[trim = 1cm 0cm 1cm 0cm, clip, width=\textwidth]{example-image-a}
\label{fig:dstates_tracking_e}
\end{subfigure}
\begin{subfigure}[t]{0.6\textwidth}
\centering
\caption{}
\includegraphics[trim = 1cm 0cm 1cm 0cm, clip, width=\textwidth]{example-image-b}
\label{fig:dstates_tracking_e}
\end{subfigure}
\end{figure}
\end{document}