scholarly journals Satellite galaxies in semi-analytic models of galaxy formation with sterile neutrino dark matter

2016 ◽  
Vol 461 (1) ◽  
pp. 60-72 ◽  
Author(s):  
Mark R. Lovell ◽  
Sownak Bose ◽  
Alexey Boyarsky ◽  
Shaun Cole ◽  
Carlos S. Frenk ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Sterile Neutrino ◽  
Satellite Galaxies ◽  
Analytic Models

Galaxy formation in semi-analytic models with sterile neutrino dark matter

2017 ◽  
Author(s):  
M. R. Lovell ◽  
S. Bose ◽  
A. Boyarsky ◽  
S. Cole ◽  
C. Frenk ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Sterile Neutrino ◽  
Analytic Models

scholarly journals The lensing properties of subhaloes in massive elliptical galaxies in sterile neutrino cosmologies

2019 ◽  
Vol 491 (1) ◽  
pp. 1295-1310 ◽  
Author(s):  
Giulia Despali ◽  
Mark Lovell ◽  
Simona Vegetti ◽  
Robert A Crain ◽  
Benjamin D Oppenheimer
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Distribution Density ◽  
Sterile Neutrino ◽  
Power Spectra ◽  
Mass Function ◽  
Elliptical Galaxies ◽  
Hydrodynamical Simulations

ABSTRACT We use high-resolution hydrodynamical simulations run with the EAGLE model of galaxy formation to study the differences between the properties of – and subsequently the lensing signal from – subhaloes of massive elliptical galaxies at redshift 0.2, in Cold and Sterile Neutrino (SN) Dark Matter models. We focus on the two 7 keV SN models that bracket the range of matter power spectra compatible with resonantly produced SN as the source of the observed 3.5 keV line. We derive an accurate parametrization for the subhalo mass function in these two SN models relative to cold dark matter (CDM), as well as the subhalo spatial distribution, density profile, and projected number density and the dark matter fraction in subhaloes. We create mock lensing maps from the simulated haloes to study the differences in the lensing signal in the framework of subhalo detection. We find that subhalo convergence is well described by a lognormal distribution and that signal of subhaloes in the power spectrum is lower in SN models with respect to CDM, at a level of 10–80 per cent, depending on the scale. However, the scatter between different projections is large and might make the use of power spectrum studies on the typical scales of current lensing images very difficult. Moreover, in the framework of individual detections through gravitational imaging a sample of ≃30 lenses with an average sensitivity of $M_{\rm {sub}} = 5 \times 10^{7}\, {\rm M}_{\odot}$ would be required to discriminate between CDM and the considered sterile neutrino models.

scholarly journals The Epoch of Reionization in Warm Dark Matter Scenarios

2021 ◽  
Author(s):  
M. Romanello ◽  
N. Menci ◽  
M. Castellano
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Luminosity Function ◽  
Volume Fraction ◽  
Sterile Neutrino ◽  
Power Spectra ◽  
Upper Limit ◽  
History Of ◽  
Initial Power ◽  
Early Galaxy

In this paper we investigate how the Reionization process is affected by early galaxy formation in different cosmological scenarios. We use a semi-analytic model with suppressed initial power spectra to obtain the UV Luminosity Function in thermal Warm Dark Matter and sterile neutrino cosmologies. We retrace the ionization history of intergalactic medium with hot stellar emission only, exploiting fixed and variable photons escape fraction models ( fesc). For each cosmology, we find an upper limit to fixed fesc, which guarantees the completion of the process at z <6.7. The analysis is tested with two limit hypothesis on high-z ionized hydrogen volume fraction, comparing our predictions with observational results.

scholarly journals Galaxies on Sub-Galactic Scales

2012 ◽  
Vol 29 (4) ◽  
pp. 383-394 ◽  
Author(s):  
Helmut Jerjen
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Near Field ◽  
Sloan Digital Sky Survey ◽  
Matter Theory ◽  
Satellite Galaxies ◽  
Star Formation Histories

AbstractThe Sloan Digital Sky Survey has been immensely successful in detecting new Milky Way satellite galaxies over the past seven years. It was instrumental in finding examples of the least luminous galaxies we know in the Universe, uncovering apparent inconsistencies between cold dark matter theory and dwarf galaxy properties, providing first evidence for a possible lower mass limit for dark matter halos in visible galaxies, and reopening the discussion about the building block scenario for the Milky Way halo. Nonetheless, these results are still drawn only from a relatively small number of galaxies distributed over an area covering about 29% of the sky, which leaves us currently with more questions than answers. The study of these extreme stellar systems is a multi-parameter problem: ages, metallicities, star formation histories, dark matter contents, population fractions and spatial distributions must be determined. Progress in the field is discussed and attention drawn to some of the limitations that currently hamper our ability to fully understand the phenomenon of the ‘ultra-faint dwarf galaxy’. In this context, the Stromlo Milky Way Satellite Survey represents a new initiative to systematically search and scrutinize optically elusive Milky Way satellite galaxies in the Southern hemisphere. In doing so, the program aims at investigating some of the challenging questions in stellar evolution, galaxy formation and near-field cosmology.

scholarly journals Warm FIRE: simulating galaxy formation with resonant sterile neutrino dark matter

2018 ◽  
Vol 483 (3) ◽  
pp. 4086-4099 ◽  
Author(s):  
Brandon Bozek ◽  
Alex Fitts ◽  
Michael Boylan-Kolchin ◽  
Shea Garrison-Kimmel ◽  
Kevork Abazajian ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Sterile Neutrino

Structure of dark matter haloes of Milky Way satellite galaxies in SIDM universes

2018 ◽  
Vol 14 (S344) ◽  
pp. 498-501
Author(s):  
Takashi Okamoto
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Galaxy Formation ◽  
Luminosity Function ◽  
Milky Way ◽  
Dwarf Galaxies ◽  
Interaction Cross Section ◽  
Large Cross Section ◽  
Stellar Feedback ◽  
Satellite Galaxies

AbstractSelf-interacting dark matter (SIDM) can create sufficiently large cores in dark matter haloes of dwarf galaxies if the self-interaction cross-section is sufficiently large on scales of dwarf galaxies. Such a large cross-section can be realized without changing the densities and shapes of cluster-size haloes by introducing a velocity dependent cross-section. Lowering the central densities of dwarf-size haloes, however, may change the strength of stellar feedback required to reproduce observed properties of dwarf galaxies such as the luminosity function of the Milky Way’s satellite galaxies. We perform simulations of galaxy formation by employing such a velocity dependent self-interaction cross-section to investigate the coupled effect of SIDM and feedback.

scholarly journals Quasars at intermediate redshift are not special; but they are often satellites

2021 ◽  
Vol 504 (1) ◽  
pp. 857-870
Author(s):  
Shadab Alam ◽  
Nicholas P Ross ◽  
Sarah Eftekharzadeh ◽  
John A Peacock ◽  
Johan Comparat ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Dark Matter Halo ◽  
Stellar Objects ◽  
The Galaxy ◽  
Quasi Stellar Objects ◽  
Satellite Galaxies ◽  
Emission Line Galaxies ◽  
Galaxy Population ◽  
Red Galaxies

ABSTRACT Understanding the links between the activity of supermassive black holes (SMBHs) at the centres of galaxies and their host dark matter haloes is a key question in modern astrophysics. The final data release of the SDSS-IV eBOSS provides the largest contemporary spectroscopic sample of galaxies and quasi-stellar objects (QSOs). Using this sample and covering the redshift interval z = 0.7–1.1, we have measured the clustering properties of the eBOSS QSOs, emission-line galaxies (ELGs), and luminous red galaxies (LRGs). We have also measured the fraction of QSOs as a function of the overdensity defined by the galaxy population. Using these measurements, we investigate how QSOs populate and sample the galaxy population, and how the host dark-matter haloes of QSOs sample the underlying halo distribution. We find that the probability of a galaxy hosting a QSO is independent of the host dark matter halo mass of the galaxy. We also find that about 60 per cent of eBOSS QSOs are hosted by LRGs and about 20–40 per cent of QSOs are hosted by satellite galaxies. We find a slight preference for QSOs to populate satellite galaxies over central galaxies. This is connected to the host halo mass distribution of different types of galaxies. Based on our analysis, QSOs should be hosted by a very broad distribution of haloes, and their occurrence should be modulated only by the efficiency of galaxy formation processes.

scholarly journals Dwarf Cosmology with the Stromlo Missing Satellites Survey

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Helmut Jerjen
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Primary Objective ◽  
Sloan Digital Sky Survey ◽  
Galaxy Formation And Evolution ◽  
National University ◽  
Formation And Evolution ◽  
Satellite Galaxies

The standard Lambda Cold Dark Matter model is considered to be a triumph of theoretical astrophysics but observations of the Milky Way and its system of satellite galaxies irresistibly signal that theory is incomplete on galactic and subgalactic scales. The Stromlo Missing Satellites (SMS) Survey is a critical endeavor to investigate at what level predictions of CDM cosmology are consistent with the observed matter distribution in the Milky Way halo. It will be the deepest, most extended search for optically elusive satellite galaxies to date, covering 20 000 square degrees of sky. The international SMS Survey collaboration will exploit 150 TB of CCD images in six filters acquired by the new SkyMapper telescope of the Australian National University over the next five years, expecting on completion photometric limits 0.5–1.0 mag fainter than the Sloan Digital Sky Survey. The primary objective of the program is to characterise the baryonic and dark matter components of a complete sample of MW satellites in the Southern hemisphere to provide stringent observational constraints for improving our understanding of how the Milky Way formed and what physical processes governed galaxy formation and evolution in general.

scholarly journals What can the outskirts of galaxies tell us about dark matter?

2016 ◽  
Vol 11 (S321) ◽  
pp. 105-107
Author(s):  
Chris Power
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Mass Density ◽  
Stellar Mass ◽  
Tidal Disruption ◽  
Matter Model ◽  
Satellite Galaxies ◽  
Dark Matter Model

AbstractDeep observations of galaxy outskirts reveal faint extended stellar components (ESCs) of streams, shells, and halos, which are ghostly remnants of the tidal disruption of satellite galaxies. We use cosmological galaxy formation simulations in Cold Dark Matter (CDM) and Warm Dark Matter (WDM) models to explore how the dark matter model influences the spatial, kinematic, and orbital properties of ESCs. These reveal that the spherically averaged stellar mass density at large galacto-centric radius can be depressed by up to a factor of ~10 in WDM models relative to the CDM model, reflecting the anticipated suppressed abundance of satellite galaxies in WDM models. However, these differences are much smaller in WDM models that are compatible with observational limits, and are comparable in size to the system-to-system variation we find within the CDM model. This suggests that it will be challenging to place limits on dark matter using only the unresolved ESC.

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