Gerardo Urrutia

Center for Theoretical Physics of the Polish Academy of Sciences · Relativistic Astrophysics

Gamma-ray bursts (GRBs) are produced during the propagation of ultra-relativistic jets. It is challenging to study the jet close to the central source, due to the high opacity of the medium. In this paper, we present numerical simulations of relativistic jets propagating through a massive, stripped envelope star associated to long GRBs, breaking ou...

After the detection of GRB 170817A, the first unambiguous off-axis gamma-ray burst (GRB), several studies tried to understand the structure of GRB jets. The initial jet structure (directly produced by the central engine) can be partially preserved, or can be completely modified by the interaction with the environment. In this study, we perform thre...

Gamma-ray bursts (GRBs) are produced during the propagation of ultra-relativistic jets. While our understanding of these jets have improved notably during the last decades, it is currently impossible to study directly the jet close to the central source, due to the high opacity of the medium. In this paper, we present numerical simulations of relat...

After the detection of GRB 170817A, the first unambiguous off-axis gamma-ray burst (GRB), several studies tried to understand the structure of GRB jets. The initial jet structure (directly produced by the central engine) can be partially preserved, or can be completely modified by the interaction with the environment. In this study, we perform thre...

The discovery of GRB 170817A, the first unambiguous off-axis short gamma-ray burst arising from a neutron star merger, has challenged our understanding of the angular structure of relativistic jets. Studies of the jet propagation usually assume that the jet is ejected from the central engine with a top-hat structure and its final structure, which d...

The discovery of GRB 170817A, the first unambiguous off-axis short gamma-ray burst arising from a neutron star merger, has challenged our understanding of the angular structure of relativistic jets. The late afterglow of GRB 170817A has been described by a structured jet seen slightly off-axis (at an observer angle of $\approx 20^\circ$--$30^\circ$...

The afterglow of GRB170817A / GW170817 was very unusual, slowly rising as $F_\nu\propto t_{\rm obs}^{0.8}\nu^{-0.6}$, peaking at $\sim150\;$days, and sharply decaying as $\sim t_{\rm obs}^{-2.2}$. VLBI observations revealed an unresolved radio afterglow image whose flux centroid apparently moved superluminally with $v_{\rm app}\approx4c$ between $7...

We present a statistical overview of the publications in theoretical high energy physics (HEP), which emerged in Latin America (LA) in the period between 1990 and 2012. Our study captures the eight Latin American nations, which are dominant in this field of research: Brazil, Mexico, Argentina, Chile, Colombia, Venezuela, Uruguay and Cuba. As an int...