scholarly journals Modeling a high velocity LMC: The formation of the Magellanic Stream

2008 ◽  
Vol 4 (S256) ◽  
pp. 117-121
Author(s):  
Chiara Mastropietro
Keyword(s):  
Dark Matter ◽  
Vertical Structure ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Low Density ◽  
Dark Matter Halos ◽  
Tidal Forces ◽  
Ram Pressure ◽  
Self Consistent ◽  
Magellanic Stream

AbstractI use high resolution N-body/SPH simulations to model the new proper motion of the Large Magellanic Cloud (LMC) within the Milky Way (MW) halo and investigate the effects of gravitational and hydrodynamical forces on the formation of the Magellanic Stream (MS). Both the LMC and the MW are fully self consistent galaxy models embedded in extended cuspy ΛCDM dark matter halos. I find that ram-pressure from a low density ionized halo is sufficient to remove a large amount of gas from the LMC's disk forming a trailing Stream that extends more than 120 degrees from the Cloud. Tidal forces elongate the satellite's disk but do not affect its vertical structure. No stars become unbound showing that tidal stripping is almost effectless.

scholarly journals Galaxies lacking dark matter in the Illustris simulation

2019 ◽  
Vol 626 ◽  
pp. A47 ◽  
Author(s):  
M. Haslbauer ◽  
J. Dabringhausen ◽  
P. Kroupa ◽  
B. Javanmardi ◽  
I. Banik
Keyword(s):  
Dark Matter ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Large Magellanic Cloud ◽  
Early Type ◽  
Number Density ◽  
The Standard Model ◽  
Ram Pressure ◽  
Self Consistent ◽  
First Time

Context. Any viable cosmological model in which galaxies interact predicts the existence of primordial and tidal dwarf galaxies (TDGs). In particular, in the standard model of cosmology (ΛCDM), according to the dual dwarf galaxy theorem, there must exist both primordial dark matter-dominated and dark matter-free TDGs with different radii. Aims. We study the frequency, evolution, and properties of TDGs in a ΛCDM cosmology. Methods. We use the hydrodynamical cosmological Illustris-1 simulation to identify TDG candidates (TDGCs) and study their present-day physical properties. The positions of galaxies in the radius–mass plane, depending on their nonbaryonic content, are compared with observational data and other simulations. We also present movies on the formation of a few galaxies lacking dark matter, confirming their tidal dwarf nature. Tidal dwarf galaxy candidates can however also be formed via other mechanisms, such as from ram-pressure-stripped material or, speculatively, from cold-accreted gas. Results. We find 97 TDGCs with Mstellar > 5 × 107M⊙ at redshift z = 0, corresponding to a co-moving number density of 2.3 × 10−4 h3 cMpc−3. The most massive TDGC has Mtotal = 3.1 × 109 M⊙, comparable to that of the Large Magellanic Cloud. Tidal dwarf galaxy candidates are phase-space-correlated, reach high metallicities, and are typically younger than dark matter-rich dwarf galaxies. Conclusions. We report for the first time the verification of the dual dwarf theorem in a self-consistent ΛCDM cosmological simulation. Simulated TDGCs and dark matter-dominated galaxies populate different regions in the radius–mass diagram in disagreement with observations of early-type galaxies. The dark matter-poor galaxies formed in Illustris-1 have comparable radii to observed dwarf galaxies and to TDGs formed in other galaxy-encounter simulations. In Illustris-1, only 0.17 percent of all selected galaxies with Mstellar = 5 × 107−109 M⊙ are TDGCs or dark matter-poor dwarf galaxies. The occurrence of NGC 1052-DF2-type objects is discussed.

scholarly journals In Pursuit of the Least Luminous Galaxies

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Beth Willman
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Field Survey ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Wide Field ◽  
Dark Matter Halos ◽  
The Past ◽  
Luminous Galaxies ◽  
Host Stars

The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as10−7LMW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the distribution, mass spectrum, and clustering scale of dark matter. Their resolved stellar populations also facilitate detailed studies of their history and mass content. To fully exploit this potential requires a well-defined census of virtually invisible galaxies to the faintest possible limits and to the largest possible distances. I review the past and present impacts of survey astronomy on the census of Milky Way dwarf galaxy companions and discuss the future of finding ultra-faint dwarf galaxies around the Milky Way and beyond in wide-field survey data.

scholarly journals Ram-Pressure Induced Star Formation in the LMC

2008 ◽  
Vol 25 (3) ◽  
pp. 138-148 ◽  
Author(s):  
Chiara Mastropietro ◽  
Andreas Burkert ◽  
Ben Moore
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Milky Way ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Gaseous Disk ◽  
Star Formation Activity ◽  
Ram Pressure ◽  
Hydrodynamical Interaction

AbstractWe use high-resolution n-body/SPH simulations to study the hydrodynamical interaction between the Large Magellanic Cloud and the hot halo of the Milky Way. We investigate whether the ram-pressure acting on the gaseous disk of the satellite can explain the peculiarities observed in the Hidistribution and the location of the recent star formation activity.

scholarly journals THE STRUCTURE OF COLD DARK MATTER HALOS: RECENT INSIGHTS FROM HIGH RESOLUTION SIMULATIONS

2009 ◽  
Vol 24 (29) ◽  
pp. 2291-2305 ◽  
Author(s):  
MARCEL ZEMP
Keyword(s):  
Dark Matter ◽  
High Resolution ◽  
Structure Formation ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Dark Matter Halos ◽  
General Properties

We review results from recent high resolution cosmological structure formation simulations, namely the Via Lactea I & II and GHALO projects. These simulations study the formation of Milky Way sized objects within a cosmological framework. We discuss the general properties of cold dark matter halos at redshift z = 0 and focus on new insights into the structure of halos we got due to the unprecedented high resolution in these simulations.

scholarly journals Tidal Tails and the Shape of the Dark Matter Halo

2005 ◽  
Vol 22 (3) ◽  
pp. 190-194 ◽  
Author(s):  
Geraint F. Lewis ◽  
Rodrigo A. Ibata
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Observational Evidence ◽  
Dark Matter Halo ◽  
Dark Matter Halos ◽  
Fundamental Understanding ◽  
Tidal Tails ◽  
Precise Interpretation

AbstractCold dark matter cosmologies successfully accounts for the distribution of matter on large scales. On smaller scales, these cosmological models predict that galaxies like our own Milky Way should be enveloped in massive dark matter halos. Furthermore, these halos should be significantly flattened or even triaxial. Recent observational evidence, drawn from the demise of the Sagittarius dwarf galaxy as it is cannibalized by our own, indicates that the potential of the Milky Way must be close to spherical. While the precise interpretation of the observational evidence is under debate, an apparently spherical halo may signify a pronounced failing of dark matter models, and may even indicate a failure in our fundamental understanding of gravity.

scholarly journals Interactions of Satellite Galaxies in Cosmological Dark Matter Halos

2004 ◽  
Vol 21 (2) ◽  
pp. 216-221 ◽  
Author(s):  
Alexander Knebe ◽  
Stuart P. D. Gill ◽  
Brad K. Gibson
Keyword(s):  
Dark Matter ◽  
Statistical Analysis ◽  
Dark Matter Halos ◽  
Simulation Data ◽  
Clear Trend ◽  
Satellite Galaxy ◽  
Self Consistent ◽  
Cluster Satellite ◽  
Satellite Galaxies ◽  
A New Technique

AbstractWe present a statistical analysis of the interactions between satellite galaxies in cosmological dark matter halos taken from fully self-consistent high-resolution simulations of galaxy clusters. We show that the number distribution of satellite encounters has a tail that extends to as many as three to four encounters per orbit. On average 30% of the substructure population had at least one encounter (per orbit) with another satellite galaxy. However, this result depends on the age of the dark matter host halo with a clear trend for more interactions in younger systems. We also report a correlation between the number of encounters and the distance of the satellites to the centre of the cluster — satellite galaxies closer to the centre experience more interactions. However, this can be simply explained by the radial distribution of the substructure population and merely reflects the fact that the density of satellites is higher in those regions.In order to find substructure galaxies we applied (and present) a new technique based upon theN-body code MLAPM. This new halo finder MHF (MLAPM’s halo finder) acts with exactly the same accuracy as theN-body code itself and is therefore free of any bias and spurious mismatch between simulation data and halo finding precision related to numerical effects.

scholarly journals Self-consistent construction of virialized wave dark matter halos

2018 ◽  
Vol 97 (10) ◽  
Author(s):  
Shan-Chang Lin ◽  
Hsi-Yu Schive ◽  
Shing-Kwong Wong ◽  
Tzihong Chiueh
Keyword(s):  
Dark Matter ◽  
Dark Matter Halos ◽  
Self Consistent ◽  
Wave Dark Matter

scholarly journals The spatial distribution of Milky Way satellites, gaps in streams and the nature of dark matter

2021 ◽  
Author(s):  
Mark R Lovell ◽  
Marius Cautun ◽  
Carlos S Frenk ◽  
Wojciech A Hellwing ◽  
Oliver Newton
Keyword(s):  
Dark Matter ◽  
Spatial Distribution ◽  
High Resolution ◽  
Radial Distribution ◽  
Cold Dark Matter ◽  
Milky Way ◽  
Self Consistent ◽  
Low Mass ◽  
Hydrodynamical Simulations ◽  
The Impact

Abstract The spatial distribution of Milky Way (MW) subhaloes provides an important set of observables for testing cosmological models. These include the radial distribution of luminous satellites, planar configurations, and the abundance of dark subhaloes whose existence or absence is key to distinguishing amongst dark matter models. We use the coco N-body simulations of cold dark matter (CDM) and 3.3 keV thermal relic warm dark matter (WDM) to predict the satellite spatial distribution in the limit that the impact of baryonic physics is minimal. We demonstrate that the radial distributions of CDM and 3.3 keV-WDM luminous satellites are identical if the minimum pre-infall halo mass to form a galaxy is >108.5 ${\, \rm M_\odot }$. The distribution of dark subhaloes is significantly more concentrated in WDM due to the absence of low mass, recently accreted substructures that typically inhabit the outer parts of a MW halo in CDM. We show that subhaloes of mass [107, 108] ${\, \rm M_\odot }$ and within 30 kpc of the centre are the stripped remnants of larger haloes in both models. Therefore their abundance in WDM is 3 × higher than one would anticipate from the overall WDM subhalo population. We estimate that differences between CDM and WDM concentration–mass relations can be probed for subhalo–stream impact parameters <2 kpc. Finally, we find that the impact of WDM on planes of satellites is likely negligible. Comprehensive comparisons with observations will require further work with high resolution, self-consistent hydrodynamical simulations.

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