One of the most important and actual issues in relativistic astrophysics is testing gravity theories and obtaining constraint values for the parameters of black holes using observational data. In this research, we aimed to explore the optical features of a Kerr-Newman black hole model in the presence of a quintessential field, which may be a candidate for a dark-energy model with a nonzero cosmological constant. First, we obtain the equations of motion for photons using the Hamilton-Jacobi formalism. We also study the horizons and shapes of the apparent regions of the photon region around the said black hole. We investigate shadows cast by the black hole using celestial coordinates in various scenarios. In addition, the impacts of quintessential field and black hole charge on the shadow radius and distortion are examined. Moreover, we look into the constraints on the spin and charge of the supermassive black holes M87$^*$ and Sagittarius A$^*$ for different values of the quintessential field using their shadow size measured by the Event Horizon Telescope Collaboration. Finally, we study the effects of the quintessential field together with black hole spin and charge on its energy emission rate by Hawking radiation and compare our result with available literature.
Comment: 15 pages, 11 figures