285 citations · 1.2k across the 24 of their papers we have counts for
26 papers
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…
Radiation-mediated shocks in GRB prompt emission
Filip Alamaa, Felix Ryde, Christoffer Lundman
The debate regarding the emission mechanism in gamma-ray bursts has been long-standing. Here, we study the spectral signatures of photospheric emission, accounting for subphotosphe…
Onset of particle acceleration during the prompt phase in gamma-ray bursts as revealed by synchrotron emission in GRB160821A
Felix Ryde, Shabnam Iyyani, Björn Ahlgren +4
The physical processes of the gamma-ray emission and particle acceleration during the prompt phase in GRBs are still unsettled. In order to perform an unambiguous physical modellin…
Inhomogeneous Jets from Neutron Star Mergers: One Jet to Rule them all
Gavin P Lamb, Lorenzo Nativi, Stephan Rosswog +4
Using the resultant profiles from 3D hydrodynamic simulations of relativistic jets interacting with neutron star merger wind ejecta, we show how the inhomogeneity of energy and vel…
An efficient method for fitting radiation-mediated shocks to gamma-ray burst data: The Kompaneets RMS approximation
Filip Samuelsson, Christoffer Lundman, Felix Ryde
Shocks that occur below a gamma-ray burst (GRB) jet photosphere are mediated by radiation. Such radiation-mediated shocks (RMSs) could be responsible for shaping the prompt GRB emi…
Are Interactions with Neutron Star Merger Winds Shaping the Jets?
Lorenzo Nativi, Gavin P. Lamb, Stephan Rosswog +2
Jets can become collimated as they propagate through dense environments and understanding such interactions is crucial for linking physical models of the environments to observatio…
Calibration of the Advanced Spectral Leakage scheme for neutron star merger simulations, and extension to smoothed-particle hydrodynamics
Davide Gizzi, Christoffer Lundman, Evan O'Connor +2
We calibrate a neutrino transport approximation, called Advanced Spectral Leakage (ASL), with the purpose of modeling neutrino-driven winds in neutron star mergers. Based on a numb…
A first-principle simulation of blast wave emergence at the photosphere of a neutron star merger
Christoffer Lundman, Andrei Beloborodov
We present the first ab initio simulation of a radiation-mediated shock emerging at the photosphere of a relativistic outflow. The simulation is performed using our code radshock t…
Can jets make the radioactively powered emission from neutron star mergers bluer?
Lorenzo Nativi, Mattia Bulla, Stephan Rosswog +5
Neutron star mergers eject neutron-rich matter in which heavy elements are synthesised. The decay of these freshly synthesised elements powers electromagnetic transients ("macronov…
Testing a model for subphotospheric dissipation in GRBs: fits to Fermi data constrain the dissipation scenario
Björn Ahlgren, Josefin Larsson, Erik Ahlberg +3
It has been suggested that the prompt emission in gamma-ray bursts (GRBs) could be described by radiation from the photosphere in a hot fireball. Such models must be tested by dire…
On the -Intensity Correlation in Gamma-Ray Bursts: Subphotospheric Heating with Varying Entropy
Felix Ryde, Hoi-Fung Yu, Hüsne Dereli-Bégué +3
The emission mechanism during the prompt phase in gamma-ray bursts (GRBs) can be investigated through correlations between spectral properties. Here, we revisit the correlation rel…
Relativistic envelopes and gamma-rays from neutron star mergers
Andrei M. Beloborodov, Christoffer Lundman, Yuri Levin
We suggest that neutron star mergers eject an ultra-relativistic envelope of mass , which helps explain the gamma-ray burst from GW170817. One ejection mechan…
Sub-photospheric turbulence as a heating mechanism in gamma-ray bursts
Jonathan Zrake, Andrei M. Beloborodov, Christoffer Lundman
We examine the possible role of turbulence in feeding the emission of gamma-ray bursts (GRBs). Turbulence may develop in a GRB jet as the result of hydrodynamic or current-driven i…
Science prospects for SPHiNX - a small satellite GRB polarimetry mission
M. Pearce, L. Eliasson, N. Kumar Iyer +9
Gamma-ray bursts (GRBs) are exceptionally bright electromagnetic events occurring daily on the sky. The prompt emission is dominated by X-/-rays. Since their discovery over 50 y…
Radiation mediated shocks in gamma-ray bursts: Subshock photon production
Christoffer Lundman, Andrei Beloborodov
Internal shocks provide a plausible heating mechanism in the jets of gamma-ray bursts (GRBs). Shocks occurring below the jet photosphere are mediated by radiation. It was previousl…
Radiation mediated shocks in gamma-ray bursts: Pair creation
Christoffer Lundman, Andrei Beloborodov, Indrek Vurm
Sub-photospheric shock dissipation is one of the main proposed mechanisms for producing the prompt gamma-ray burst (GRB) emission. Such shocks are mediated by scattering of radiati…
Emission from accelerating jets in gamma-ray bursts: Radiation dominated flows with increasing mass outflow rates
Felix Ryde, Christoffer Lundman, Zeynep Acuner
We study the narrowest spectra expected from gamma-ray bursts. We present an analytical function for the spectrum that is emitted from the photosphere of a radiation-dominated flow…
Polarization of gamma-ray bursts in the dissipative photosphere model
Christoffer Lundman, Indrek Vurm, Andrei M. Beloborodov
The MeV spectral peak of gamma-ray bursts (GRBs) is best explained as photospheric emission from a dissipative relativistic jet. The observed non-blackbody spectrum shows that sub-…
Polarization properties of photospheric emission from relativistic, collimated outflows
Christoffer Lundman, Asaf Pe'er, Felix Ryde
We consider the polarization properties of photospheric emission originating in jets consisting of a highly relativistic core of opening angle theta_j and Lorentz factor Gamma_0, a…
Variable jet properties in GRB110721A: Time resolved observations of the jet photosphere
Shabnam Iyyani, Felix Ryde, Magnus Axelsson +8
{\it Fermi Gamma-ray Space Telescope} observations of GRB110721A have revealed two emission components from the relativistic jet: emission from the photosphere, peaking at $\sim 10…
A theory of photospheric emission from relativistic, collimated outflows
Christoffer Lundman, Asaf Pe'er, Felix Ryde
Relativistic outflows in the form of jets are common in many astrophysical objects. By their very nature, jets have angle dependent velocity profiles, Gamma = Gamma(r, theta, phi),…
GRB110721A: An extreme peak energy and signatures of the photosphere
The Fermi LAT Collaboration, the GBM Collaboration, A. Pe'er
GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The burst consisted o…
Subphotospheric heating in GRBs: analysis and modeling of GRB090902B as observed by Fermi
T. Nymark, M. Axelsson, C. Lundman +3
We analyze the spectral evolution of GRB 090902B and show that subphotospheric dissipation can explain both the spectra and the spectral evolution. The emission from a GRB photosph…
Observational evidence of dissipative photospheres in gamma-ray bursts
Felix Ryde, Asaf Pe'er, Tanja Nymark +11
The emission from a gamma-ray burst (GRB) photosphere can give rise to a variety of spectral shapes. The spectrum can retain the shape of a Planck function or it can be broadened a…