We use 3D radiation–hydrodynamic simulations to study the effects of an external photoionization source on structure a Herbig–Haro (HH) jet launched from young stellar object. Different ionizing photon rates are considered as well time-dependent ejection velocity and density. From our numerical results, synthetic Hα emission maps computed in order how affects observed morphology counterjet. fin...

We describe recently proposed algorithms, denoted scaled gradient projection (SGP) methods, which provide efficient and accurate reconstructions of astronomical images. We restrict the presentation to the case of data affected by Poisson noise and of nonnegative solutions; both maximum likelihood and Bayesian approaches are considered. Numerical results are presented for discussing the practica...