How to constrain warm dark matter with the Lyman-α forest

2021 ◽  
Vol 502 (2) ◽  
pp. 2356-2363
Author(s):  
Antonella Garzilli ◽  
Andrii Magalich ◽  
Oleg Ruchayskiy ◽  
Alexey Boyarsky
Keyword(s):  
Dark Matter ◽  
High Resolution ◽  
Power Spectrum ◽  
Systematic Uncertainty ◽  
Thermal Effects ◽  
Specific Class ◽  
Small Scales ◽  
History Of ◽  
The Universe

ABSTRACT The flux power spectrum (FPS) of the high-resolution Lyman-α forest data exhibits suppression at small scales. The origin of this suppression can be due to long-sought warm dark matter (WDM) or to thermal effects, related to the largely unknown reionization history of the Universe. Previous works explored a specific class of reionization histories that exhibit sufficiently strong thermal suppression and leave little room for WDM interpretation. In this work, we choose a different class of reionization histories, fully compatible with available data on evolution of reionization, but much colder than the reionization histories used by previous authors in determining the nature of dark matter, thus leaving the broadest room for the WDM interpretation of the suppression in the FPS. We find that WDM thermal relics with masses below 1.9 keV (95 per cent CL) would produce a suppression at scales that are larger than observed maximum of the FPS, independently of assumptions about thermal effects. This WDM mass is significantly lower than previously claimed bounds, demonstrating the level of systematic uncertainty of the Lyman-α forest method, due to the previous modelling. We also discuss how this uncertainty may affect also data at large scales measured by eBOSS(Baryon Oscillation Spectroscopic Survey).

scholarly journals The Lyman-α forest as a diagnostic of the nature of the dark matter

2019 ◽  
Vol 489 (3) ◽  
pp. 3456-3471 ◽  
Author(s):  
Antonella Garzilli ◽  
Andrii Magalich ◽  
Tom Theuns ◽  
Carlos S Frenk ◽  
Christoph Weniger ◽  
...  
Keyword(s):  
Dark Matter ◽  
High Temperature ◽  
High Resolution ◽  
Power Spectrum ◽  
Early Universe ◽  
Thermal Effects ◽  
Cold Dark Matter ◽  
Sterile Neutrinos ◽  
Hydrodynamic Simulations ◽  
Very High

ABSTRACT The observed Lyman-α flux power spectrum (FPS) is suppressed on scales below ${\sim} ~ 30\, {\rm km\, s}^{-1}$. This cut-off could be due to the high temperature, T0, and pressure, p0, of the absorbing gas or, alternatively, it could reflect the free streaming of dark matter particles in the early universe. We perform a set of very high resolution cosmological hydrodynamic simulations in which we vary T0, p0, and the amplitude of the dark matter free streaming, and compare the FPS of mock spectra to the data. We show that the location of the dark matter free-streaming cut-off scales differently with redshift than the cut-off produced by thermal effects and is more pronounced at higher redshift. We, therefore, focus on a comparison to the observed FPS at z > 5. We demonstrate that the FPS cut-off can be fit assuming cold dark matter, but it can be equally well fit assuming that the dark matter consists of ∼7 keV sterile neutrinos in which case the cut-off is due primarily to the dark matter free streaming.

scholarly journals Displaced new physics at colliders and the early universe before its first second

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lorenzo Calibbi ◽  
Francesco D’Eramo ◽  
Sam Junius ◽  
Laura Lopez-Honorez ◽  
Alberto Mariotti
Keyword(s):  
Dark Matter ◽  
Early Universe ◽  
Upper Bound ◽  
New Physics ◽  
Early History ◽  
Relic Density ◽  
History Of ◽  
Indirect Information ◽  
The Universe

Abstract Displaced vertices at colliders, arising from the production and decay of long-lived particles, probe dark matter candidates produced via freeze-in. If one assumes a standard cosmological history, these decays happen inside the detector only if the dark matter is very light because of the relic density constraint. Here, we argue how displaced events could very well point to freeze-in within a non-standard early universe history. Focusing on the cosmology of inflationary reheating, we explore the interplay between the reheating temperature and collider signatures for minimal freeze-in scenarios. Observing displaced events at the LHC would allow to set an upper bound on the reheating temperature and, in general, to gather indirect information on the early history of the universe.

scholarly journals A dark clue to seesaw and leptogenesis in a pseudo-Dirac singlet doublet scenario with (non)standard cosmology

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Partha Konar ◽  
Ananya Mukherjee ◽  
Abhijit Kumar Saha ◽  
Sudipta Show
Keyword(s):  
Dark Matter ◽  
Thermal History ◽  
Direct Detection ◽  
Critical Role ◽  
Mass Term ◽  
Baryon Asymmetry ◽  
Dark Sector ◽  
Lepton Asymmetry ◽  
History Of ◽  
The Universe

Abstract We propose an appealing alternative scenario of leptogenesis assisted by dark sector which leads to the baryon asymmetry of the Universe satisfying all theoretical and experimental constraints. The dark sector carries a non minimal set up of singlet doublet fermionic dark matter extended with copies of a real singlet scalar field. A small Majorana mass term for the singlet dark fermion, in addition to the typical Dirac term, provides the more favourable dark matter of pseudo-Dirac type, capable of escaping the direct search. Such a construction also offers a formidable scope to radiative generation of active neutrino masses. In the presence of a (non)standard thermal history of the Universe, we perform the detailed dark matter phenomenology adopting the suitable benchmark scenarios, consistent with direct detection and neutrino oscillations data. Besides, we have demonstrated that the singlet scalars can go through CP-violating out of equilibrium decay, producing an ample amount of lepton asymmetry. Such an asymmetry then gets converted into the observed baryon asymmetry of the Universe through the non-perturbative sphaleron processes owing to the presence of the alternative cosmological background considered here. Unconventional thermal history of the Universe can thus aspire to lend a critical role both in the context of dark matter as well as in realizing baryogenesis.

scholarly journals Dark Stars: Dark matter in the first stars leads to a new phase of stellar evolution

2008 ◽  
Vol 4 (S255) ◽  
pp. 56-60 ◽  
Author(s):  
Katherine Freese ◽  
Douglas Spolyar ◽  
Anthony Aguirre ◽  
Peter Bodenheimer ◽  
Paolo Gondolo ◽  
...  
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Cross Section ◽  
Stellar Evolution ◽  
Weakly Interacting Massive Particles ◽  
First Stars ◽  
History Of ◽  
Born Again ◽  
The Universe ◽  
New Phase

AbstractThe first phase of stellar evolution in the history of the universe may be Dark Stars, powered by dark matter heating rather than by fusion. Weakly interacting massive particles, which are their own antiparticles, can annihilate and provide an important heat source for the first stars in the the universe. This talk presents the story of these Dark Stars. We make predictions that the first stars are very massive (~800M⊙), cool (6000 K), bright (~106L⊙), long-lived (~106years), and probable precursors to (otherwise unexplained) supermassive black holes. Later, once the initial DM fuel runs out and fusion sets in, DM annihilation can predominate again if the scattering cross section is strong enough, so that a Dark Star is born again.

scholarly journals Origin of the galaxy morphology

2003 ◽  
Vol 208 ◽  
pp. 431-432
Author(s):  
N. Nakasato
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
High Resolution ◽  
Cold Dark Matter ◽  
Star Formation History ◽  
The Galaxy ◽  
Particle Hydrodynamics ◽  
History Of ◽  
Analytic Models ◽  
Galaxy Morphology

In the current most plausible Cold Dark Matter (CDM) cosmology, larger halos increase their mass by the progressive mergers of smaller clumps. Due to these progressive merger events, galaxies have formed and evolved. Such merger events could trigger star bursts depending on mass of a merging object. In other words, star formation history reflects the strength of the interaction between a galaxy and merging objects. Also, a several merger events strongly affect the development of the morphology of galaxies as assumed in semi-analytic models. In the most advanced semi-analytic models, N-body simulations of dark matter particles are used to obtain the merging history of halos. By combining the description of radiative cooling, hydrodynamics and star formation with the obtained merging history, such models successfully have explained the various qualitative predictions. Here, we show the results of similar approach but using a fullly numerical model. In contrast to the semi-analytic models, we use our high resolution Smoothed Particle Hydrodynamics (SPH) models. With our SPH code, we try to tackle the problem of the galaxy morphology. We have done a several handful high-resolution SPH simulations and analyzed the merging history of such models. Accordingly, we can see the relation between the obtained morphology and the merging history or other physical properties of the model.

scholarly journals Gravitino Warm Dark Matter Motivated by Gauge-Mediated Supersymmetry Breaking Theories

1997 ◽  
Vol 12 (17) ◽  
pp. 1275-1282 ◽  
Author(s):  
M. Kawasaki ◽  
Naoshi Sugiyama ◽  
T. Yanagida
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Supersymmetry Breaking ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Baryon Density ◽  
Present Observation ◽  
Matter Model ◽  
The Universe ◽  
Dark Matter Model

Gauge-mediated supersymmetry breaking models suggest the presence of the light gravitino with mass ~ 1 keV which can be warm dark matter in our universe. We consider large scale structure of the universe in the warm dark matter model and find that the power spectrum of the gravitino dark matter is almost the same as that of a cold dark matter at scales larger than about 1 Mpc. We also study the Ly α absorption systems which are presumed to be galaxies at high redshifts and show that the baryon density in the damped Ly α absorption systems predicted by the gravitino dark matter model is quite consistent with the present observation.

scholarly journals Dark Matter Realism

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Niels C. M. Martens
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Logical Empiricism ◽  
Mass Energy ◽  
Current State ◽  
The Standard Model ◽  
Luminous Matter ◽  
History Of ◽  
The Universe ◽  
Current Stage

AbstractAccording to the standard model of cosmology, $$\Lambda $$ Λ CDM, the mass-energy budget of the current stage of the universe is not dominated by the luminous matter that we are familiar with, but instead by some form of dark matter (and dark energy). It is thus tempting to adopt scientific realism about dark matter. However, there are barely any constraints on the myriad of possible properties of this entity—it is not even certain that it is a form of matter. In light of this underdetermination I advocate caution: we should not (yet) be dark matter realists. The “not(-yet)-realism” that I have in mind is different from Hacking’s (Philos Sci 56 (4), 555–581, 1989) anti-realism, in that it is semantic rather than epistemological. It also differs from the semantic anti-realism of logical empiricism, in that it is naturalistic, such that it may only be temporary and does not automatically apply to all other unobservables (or even just to all other astronomical unobservables, as with Hacking’s anti-realism). The argument is illustrated with the analogy of the much longer history of the concept of a gene, as the current state of the concept of dark matter resembles in some relevant ways that of the early concept of genes.

5. Cosmology

2017 ◽  
pp. 58-82
Author(s):  
Timothy Clifton
Keyword(s):  
Dark Matter ◽  
Large Scale ◽  
Gravitational Interaction ◽  
Albert Einstein ◽  
Scientific Discipline ◽  
Normal Matter ◽  
History Of Cosmology ◽  
History Of ◽  
Edwin Hubble ◽  
The Universe

Cosmology began as a scientific discipline at the beginning of the 20th century, with the work of Albert Einstein and Edwin Hubble. Gravitational interaction is fundamental to cosmology, as gravity dominates over all other forces on large-scale distances. ‘Cosmology’ outlines the modern history of cosmology, discussing how studies have provided knowledge on the early Universe and its expansion. The Concordance Model proposes that only c.5 per cent of the energy in the Universe is in the form of normal matter; c.25 per cent is in the form of the gravitationally attractive dark matter; and the remaining c.70 per cent is in the form of the gravitationally repulsive dark energy. But there is still much to learn.

Sign in / Sign up

Export Citation Format

Share Document