85 research outputs found
Star Formation and Chemical Enrichment in Protoclusters
We examine star formation and chemical enrichment in protoclusters (PCs)
using cosmological zoom-in hydrodynamic simulations. We find that the total
star formation rate (SFR) in all PC (M) reaches
at , equivalent to the observed
PCs. The SFR in the Core region accounts for about of the total star
formation in the PC at , suggesting the importance of the outer
regions to reveal the evolution of galaxy clusters. We find that the total SFR
of PC is dominated by galaxies with
, while more massive
galaxies dominate the SFR in the Core. For the chemical abundance evolution, we
find that the higher-density region has a higher metallicity and faster
evolution. We show that the [O/Fe] vs. [Fe/H] relation turns down in the Core
at due to the enrichment of Fe by Type Ia supernovae. We find no
environmental effects for the mass--metallicity relations (MZR) or (N/O)
vs. (O/H) for galaxies. We find that the chemical enrichment in galaxy
clusters proceeds faster in the high redshift Universe (). Our work will
benefit future tomographic observations, particularly using PCs as unique
probes of accelerated structure formation and evolution in high-density regions
of the universe.Comment: 19 pages, 18 figures, 2 tables, 2 appendices, Accepted for
publication in MNRA
Detection Prospects for Majorana Fermion WIMPless Dark Matter
We consider both velocity-dependent and velocity-independent contributions to
spin-dependent (SD) and spin-independent (SI) nuclear scattering (including
one-loop corrections) of WIMPless dark matter, in the case where the dark
matter candidate is a Majorana fermion. We find that spin-independent
scattering arises only from the mixing of exotic squarks, or from
velocity-dependent terms. Nevertheless (and contrary to the case of MSSM
neutralino WIMPs), we find a class of models which cannot be detected through
SI scattering, but can be detected at IceCube/DeepCore through SD scattering.
We study the detection prospects for both SI and SD detection strategies for a
large range of Majorana fermion WIMPless model parameters.Comment: 14 pages, 3 figures. v2: updated to match published versio
A case of meningococcal meningitis with multiple cerebellar microbleeds detected by susceptibility-weighted imaging
- β¦