In the 1930s, F. Zwicky discussed the motions of the galaxies that comprised the elements of the Coma Cluster of galaxies. He noted that their velocities were not falling off with distance from the ...center of the cluster as would be expected on the basis of Newton’s theory of gravity.
In this chapter we outline some aspects of the N-body simulation code used in this thesis as well as the modifications made to the code to include the effects of various dark energy cosmologies. We ...also describe how the initial conditions for the simulations are set up.
To identify the relationship between the observational data and the parameters of the particles of dark matter, we turn to the description of gravitational instability, used in Chap. 4, where the ...formation of primordial black holes (PBH) was discussed.
After the high drama of major mergers, maybe it is time to calm down a little, to find a slower, lower energy activity to observe in the world of galaxies. Minor and micro mergers fit that bill, and ...were mentioned without being defined in the last chapter. Unfortunately, although the term “minor merger” is used frequently in the literature, there is no standard or universally agreed upon definition. Micro merger is not even a standard term, but it is one that I find convenient.
We present new constraints on the mass of warm dark matter (WDM) particles derived from the Lyman-α flux power spectrum of 55 high-resolution Lyman-α forest spectra at 2.0 < z < 6.4 obtained with the ...HIRES spectrograph at the Keck telescope. From the HIRES spectra alone, we obtain a lower limit of mWDM ≳ 1.2 keV (2σ) if the WDM consists of early decoupled thermal relics and mWDM ≳ 5.6 keV (2σ) for sterile neutrinos. This result improves the previous constraints from high-resolution spectra at lower redshift by a factor two. Adding the Sloan Digital Sky Survey Lyman-α flux power spectrum at 2.2 < z < 4.2 from a large sample of low resolution spectra we get mWDM ≳ 4 keV and mWDM ≳ 28 keV (2σ) for thermal relics and sterile neutrinos, respectively. This is also a factor two improvement compared to previous combined analysis of high and low-resolution data. The small scale matter power spectrum probed by the high-resolution high-redshift HIRES data is instrumental for this improvement.
How we ourselves acquire, store and transmit mental information – how our minds process (input, manipulate and output) information – would seem to be ultimate questions in bioinformatics. Having ...‘solved’ the corresponding questions on genetic information in the 50s and 60s, Crick moved to brain research in 1976. One would have thought the two rules for his success in genetics would still apply: seek the simplest experimental system; find the store first and then work out how it fills and empties. For his experiments Crick had chosen the smallest known biological forms – the viruses that infect bacteria. And he went directly to the genetic store – DNA. When its structure was known, solutions to the acquisition problem (replication and mutation) and the transmission problem (transcription and translation) fell neatly into place. But neither rule was to be followed in his brain research.
In this paper we introduce Enzo, a 3D MPI-parallel Eulerian block-structured adaptive mesh refinement cosmology code. Enzo is designed to simulate cosmological structure formation, but can also be ...used to simulate a wide range of astrophysical situations. Enzo solves dark matter N-body dynamics using the particle-mesh technique. The Poisson equation is solved using a combination of fast fourier transform (on a periodic root grid) and multigrid techniques (on non-periodic subgrids). Euler’s equations of hydrodynamics are solved using a modified version of the piecewise parabolic method. Several additional physics packages are implemented in the code, including several varieties of radiative cooling, a metagalactic ultraviolet background, and prescriptions for star formation and feedback. We also show results illustrating properties of the adaptive mesh portion of the code. Information on profiling and optimizing the performance of the code can be found in the contribution by James Bordner in this volume.
From DAMA/NaI to DAMA/LIBRA at LNGS Bernabei, R.; Belli, P.; Montecchia1, F. ...
The 2nd International Conference on Nuclear Physics in Astrophysics
Book Chapter
DAMA is an observatory for rare processes based on the development and use of various kinds of radiopure scintillators; it is operative deep underground at the Gran Sasso National Laboratory of the ...INFN. Several low background setups have been realized and many rare processes have been investigated. In particular, the DAMA/NaI setup (⋍ 100 kg highly radiopure NaI(Tl)) has effectively investigated the model-independent annual modulation signature; the data of seven annual cycles (total exposure of 107731 kg × d) have offered a 6.3σ C.L. model-independent evidence for the presence of a Dark Matter particle component in the galactic halo. Some of the many possible corollary model-dependent quests for the candidate particle have also been investigated. At present, the second-generation DAMA/LIBRA setup (⋍ 250 kg highly radiopure NaI(Tl)) is in operation deep underground. This paper summarizes the main aspects.
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