TY  - JOUR
A1  - Gieg, Henrique
A1  - Schianchi, Federico
A1  - Dietrich, Tim
A1  - Ujevic, Maximiliano
T1  - Incorporating a Radiative Hydrodynamics Scheme in the Numerical-Relativity Code BAM
JF  - Universe : open access journal
N2  - To study binary neutron star systems and to interpret observational data such as gravitational-wave and kilonova signals, one needs an accurate description of the processes that take place during the final stages of the coalescence, for example, through numerical-relativity simulations. In this work, we present an updated version of the numerical-relativity code BAM in order to incorporate nuclear-theory-based equations of state and a simple description of neutrino interactions through a neutrino leakage scheme. Different test simulations, for stars undergoing a neutrino-induced gravitational collapse and for binary neutron stars systems, validate our new implementation. For the binary neutron stars systems, we show that we can evolve stably and accurately distinct microphysical models employing the different equations of state: SFHo, DD2, and the hyperonic BHB Lambda phi. Overall, our test simulations have good agreement with those reported in the literature.
KW  - numerical relativity
KW  - binary neutron stars
KW  - neutrinos
KW  - leakage scheme
Y1  - 2022
U6  - https://doi.org/10.3390/universe8070370
SN  - 2218-1997
VL  - 8
IS  - 7
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Emma, Mattia
A1  - Schianchi, Federico
A1  - Pannarale, Francesco
A1  - Sagun, Violetta
A1  - Dietrich, Tim
T1  - Numerical simulations of dark matter admixed neutron star binaries
JF  - Particles
N2  - Multi-messenger observations of compact binary mergers provide a new way to constrain the nature of dark matter that may accumulate in and around neutron stars. In this article, we extend the infrastructure of our numerical-relativity code BAM to enable the simulation of neutron stars that contain an additional mirror dark matter component. We perform single star tests to verify our code and the first binary neutron star simulations of this kind. We find that the presence of dark matter reduces the lifetime of the merger remnant and favors a prompt collapse to a black hole. Furthermore, we find differences in the merger time for systems with the same total mass and mass ratio, but different amounts of dark matter. Finally, we find that electromagnetic signals produced by the merger of binary neutron stars admixed with dark matter are very unlikely to be as bright as their dark matter-free counterparts. Given the increased sensitivity of multi-messenger facilities, our analysis gives a new perspective on how to probe the presence of dark matter.
KW  - numerical relativity
KW  - dark matter
KW  - neutron stars
KW  - equation of state;
KW  - gravitational-wave astronomy
KW  - multi-messenger astrophysics
Y1  - 2022
U6  - https://doi.org/10.3390/particles5030024
SN  - 2571-712X
VL  - 5
IS  - 3
SP  - 273
EP  - 286
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Moesta, Philip
A1  - Andersson, Lars
A1  - Metzger, Jan
A1  - Szilagyi, Bela
A1  - Winicour, Jeffrey
T1  - The merger of small and large black holes
JF  - Classical and quantum gravit
N2  - We present simulations of binary black-hole mergers in which, after the common outer horizon has formed, the marginally outer trapped surfaces (MOTSs) corresponding to the individual black holes continue to approach and eventually penetrate each other. This has very interesting consequences according to recent results in the theory of MOTSs. Uniqueness and stability theorems imply that two MOTSs which touch with a common outer normal must be identical. This suggests a possible dramatic consequence of the collision between a small and large black hole. If the penetration were to continue to completion, then the two MOTSs would have to coalesce, by some combination of the small one growing and the big one shrinking. Here we explore the relationship between theory and numerical simulations, in which a small black hole has halfway penetrated a large one.
KW  - black holes
KW  - numerical relativity
KW  - trapped surfaces
Y1  - 2015
U6  - https://doi.org/10.1088/0264-9381/32/23/235003
SN  - 0264-9381
SN  - 1361-6382
VL  - 32
IS  - 23
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -