938 research outputs found
Cosmological Simulation for Fuzzy Dark Matter Model
Fuzzy Dark Matter (FDM), motivated by string theory, has recently become a
hot candidate for dark matter. The rest mass of FDM is believed to be eV and the corresponding de-Broglie wave length is kpc.
Therefore, the quantum effect of FDM plays an important role in structure
formation. In order to study the cosmological structure formation in FDM model,
several simulation techniques have been introduced. We review the current
status and challenges in the cosmological simulation for the FDM model in this
paper.Comment: 10 pages, 2 tables, published on Front. Astron. Space Sci. under the
topic: Dark Matter - Where is it? What is it
R-process nucleosynthesis during explosion of low-mass neutron stars in close binaries
We investigate the explosion of low-mass neutron stars through Newtonian
hydrodynamic simulations. We couple the hydrodynamics to a nuclear reaction
network consisting of isotopes to study the impact of nuclear
reactions, mainly neutron capture, -decays, and spontaneous fission of
nuclei, on the development of hydrodynamic instability of a neutron star. We
show that after mass removal from the surfaces, low-mass neutron stars undergo
delayed explosion, and an electron anti-neutrino burst with a peak luminosity
of erg s is emitted, while the ejecta is heated to
K. A robust r-process nucleosynthesis is realized in the ejecta.
Lanthanides and heavy elements near the second and third r-process peaks are
synthesized as end products of nucleosynthesis, suggesting that the explosions
of low-mass neutron stars could be a potentially important source of solar
chemical elements.Comment: 12 pages, 13 figure
Accretion-induced Collapse of Dark Matter-admixed Rotating White Dwarfs: Dynamics and Gravitational-wave Signals
We present two-dimensional hydrodynamic simulations of the accretion-induced
collapse (AIC) of rotating white dwarfs admixed with an extended component of
dark matter (DM) comprising of sub-GeV degenerate fermionic DM particles. We
find that the DM component would follow the collapse of the normal matter (NM)
component to become a bound DM core. Thus, we demonstrate how a DM-admixed
neutron star could form through DM-admixed AIC (DMAIC) for the first time, with
the dynamics of DM taken into account. The gravitational-wave (GW) signature
from the DMAIC shows distinctive features. In the diffusive DM limit, the DM
admixture indirectly suppresses the post-bounce spectral peak of the NM GWs. In
the compact DM limit, the collapse dynamics of the DM in a Milky Way event
generate GWs that are strong enough to be detectable by Advanced LIGO as
continuous low-frequency ( Hz) signals after the NM core bounce. Our
study not only is the first-ever computation of GW from a collapsing DM object
but also provides the key features to identify DM in AIC events through future
GW detections.Comment: 14 pages, 13 figure
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