6 papers
EXPO: a quantum leap in fast, wide-band X-ray polarimetry for astrophysics
Paolo Soffitta, Sebastien Guillot, Ian Hutchinson +137
The Enhanced X-ray Polarimetry Observatory (EXPO) is a mission concept proposed to ESA as an M8 candidate, with a prospective launch in 2041. Building on the scientific success of…
Wind-confined jet collimation revealed by the acceleration-phase photosphere of GRB 220426A
Felix Ryde, Asaf Pe'er
We analyze the prompt emission of the exceptionally bright GRB 220426A observed by Fermi/GBM, whose time-resolved spectra are among the narrowest measured in any GRB. Here we show…
From Internal Collision to Photon Escape: First-Principles Modeling of Radiation-Mediated Shocks in Gamma-Ray Burst Photospheres
Jona Nordin Nobuoka, Filip Alamaa, Felix Ryde +1
Modeling subphotospheric shocks in a gamma-ray burst (GRB) is challenging due to the various timescales that must be resolved, and the fact that the same radiation dynamically medi…
An Intertwined Short and Long GRB with 4-minute Separation
Liang Li, Yu Wang, Bing Zhang +19
Gamma-ray bursts (GRBs), the most energetic transients in the Universe, are traditionally classified into long-duration ( s) and short-duration ( s) events, ass…
Photospheric emission from GRB 211211A altered by a strong radiation-mediated shock
Oscar Wistemar, Filip Alamaa, Felix Ryde
Gamma-ray burst (GRB) spectra are typically non-thermal, with many including two spectral breaks suggestive of optically-thin emission. However, the emitted spectrum from a GRB pho…
A generalized method to measure the Lorentz factor from gamma-ray burst photospheric emission
Oscar Wistemar, Felix Ryde, Filip Alamaa
The properties of gamma-ray bursts (GRBs) that are inferred from observations depend on the value of the bulk Lorentz factor, . Consequently, accurately estimating it is an imp…