scholarly journals Simulating the galactic system in interaction AM 2229-735 and the formation of its polar structure

2019 ◽  
Author(s):  
Luis F Quiroga ◽  
J C Muñoz-Cuartas ◽  
I Rodrigues ◽  
Noam I Libeskind
Keyword(s):  
Dark Matter ◽  
Initial Conditions ◽  
Polar Structure ◽  
Polar Ring ◽  
Galactic System ◽  
Galaxy Disk ◽  
Ring Galaxies ◽  
Tidal Stream ◽  
Minor Mergers ◽  
A Minor

Abstract We study the formation of polar ring galaxies via minor mergers. We used N-body+hydrodynamics simulations to reproduce the dynamics of the observed system AM 2229-735 that is a minor merger whose interaction signals are those of a progenitor for a polar ring galaxy. We used the observational information of the system to get initial conditions for the orbit and numerical realisations of the galaxies to run the simulations. Our simulations reproduce the global characteristics of interaction observed in the system such as arms and a material bridge connecting the galaxies. As a merger remnant, we found a quasi-stable and self gravitating planar tidal stream with dark matter, stars and gas orbiting in a plane approximately perpendicular to the main galaxy disk leading in the future to a polar ring galaxy. We studied the dynamical conditions of the polar structure and found evidence suggesting that this kind of merger remnant can settle down in a disk-like structure with isothermal support, providing inspiring evidence about the process of formation of galactic disks and providing a potentially independent scenario to study the presence of dark matter in this kind of galaxies.

scholarly journals To be or not to be oblate: the shape of the dark matter halo in polar ring galaxies

2014 ◽  
Vol 441 (3) ◽  
pp. 2650-2662 ◽  
Author(s):  
S. A. Khoperskov ◽  
A. V. Moiseev ◽  
A. V. Khoperskov ◽  
A. S. Saburova
Keyword(s):  
Dark Matter ◽  
Dark Matter Halo ◽  
Polar Ring ◽  
Ring Galaxies

scholarly journals SUBSTRUCTURE FORMATION IN TIDAL STREAMS OF GALACTIC MINOR MERGERS

2019 ◽  
Vol 55 (2) ◽  
pp. 273-288
Author(s):  
D. A. Noreña ◽  
J. C. Muñoz-Cuartas ◽  
L. F. Quiroga ◽  
N. Libeskind
Keyword(s):  
Dark Matter ◽  
Dynamical Stability ◽  
Stellar Clusters ◽  
Tidal Stream ◽  
Substructure Formation ◽  
Satellite Galaxies ◽  
Minor Mergers ◽  
Tidal Streams

In this work, we explore the idea that substructures like stellar clusters could be formed from the tidal stream produced in galactic minor mergers. We use N -body and SPH simulations of satellite galaxies interacting with a larger galaxy. We study the distribution of mass in streams to identify overdensity regions in which a substructure could be formed. We find that without gas, no substructure forms as none of the overdensities shows a definite morphology nor dynamical stability. Including gas we find that several clumps appear and prove to be real long standing physical structures (t ≥ 1 Gyr). We analyze the orbits, ages and masses of these structures, finding their correspondence with the halo subsystems. We conclude that it is possible to form cluster-like structures from the material in tidal streams and find evidence in favour of the presence of dark matter in these systems.

scholarly journals Dark Matter in the Polar Ring Spiral NGC 660

1995 ◽  
Vol 164 ◽  
pp. 435-435
Author(s):  
Wim Van Driel
Keyword(s):  
Dark Matter ◽  
Three Dimensional ◽  
Polar Ring ◽  
Ring Galaxies ◽  
Dimensional Distribution

Polar ring galaxies, where rotation velocities can be measured in two orthogonal planes, are generally considered to be ideal objects for studies of the three-dimensional distribution of dark matter in galaxies.

9. The Outer Galactic Environment

1988 ◽  
Vol 20 (01) ◽  
pp. 396-404
Keyword(s):  
Dark Matter ◽  
Galactic Plane ◽  
Dwarf Galaxies ◽  
Single System ◽  
Narrow Strip ◽  
Polar Ring ◽  
Ring Galaxies

One of the highlights of the study of the galactic environment is the demonstration that companions and hydrogen clouds surrounding our Galaxy form a ring-like structure similar to that surrounding external polar-ring galaxies. Probably this feature is common in giant galaxies. Dwarf galaxies may possess their own dark coronas, which fact, if confirmed, puts severe constraints on the nature of dark matter. Available evidence confirms earlier suggestions that our Galaxy with its massive corona, companions, and surrounding gas forms a single system with many mutual interactions. Most companions of our Galaxy as well as the main hydrogen streams are located in a narrow strip inclined 70° to the galactic plane.

scholarly journals Distribution of Dark Matter in Polar Ring Galaxies

1987 ◽  
Vol 117 ◽  
pp. 315-315
Author(s):  
Bradley C. Whitmore ◽  
Douglas B. McElroy ◽  
François Schweizer ◽  
Vera C. Rubin
Keyword(s):  
Dark Matter ◽  
Gravitational Potential ◽  
Three Dimensions ◽  
Polar Ring ◽  
Ring Galaxies ◽  
Spherical Potential

The discovery of SO galaxies with polar rings makes it possible to directly measure the gravitational potential of a galaxy in three dimensions. Schweizer, Whitmore and Rubin (1983) find a spherical potential in the case of A0136-0801. We have observed three more polar ring galaxies using the 4 meter telescope at CTIO. The following table summarizes the results for these three systems as well as A0136-0801, and figure 1 shows an example of the data.

scholarly journals Structure and Kinematics of Polar Ring Galaxies: New Observations and Estimation of the Dark Halo Shape

2015 ◽  
Vol 24 (1) ◽  
Author(s):  
A. Moiseev ◽  
S. Khoperskov ◽  
A. Khoperskov ◽  
K. Smirnova ◽  
A. Smirnova ◽  
...  
Keyword(s):  
Dark Matter ◽  
Observational Data ◽  
Dark Matter Halo ◽  
Dark Halo ◽  
Dark Matter Halos ◽  
Ionized Gas ◽  
Polar Ring ◽  
Gas Kinematics ◽  
Open Questions ◽  
Ring Galaxies

AbstractThe polar ring galaxies (PRGs) represent an interesting type of peculiar systems in which the outer matter is rotating in the plane which is roughly perpendicular to the disk of the main galaxy. Despite the long-lasting study of the PRGs, the amount of observational data detailed enough is insufficient; there still remain many open questions. Among the most interesting issues, there are: estimating the flattening of dark matter halos in these systems and verifying the assumption that the most massive polar structures were formed by accretion of the matter from intergalactic filaments. The new catalog recently compiled by our team using SDSS images increased, by several times, the number of known PRGs. The current paper gives an overview of our latest results on the study of morphological and photometric structure of the PRGs. Using the stellar and ionized gas kinematics data based on spectroscopic observations with the Russian 6-m telescope, we estimate the shape of dark matter halo in individual galaxies.

Distribution of Dark Matter in Polar Ring Galaxies

1987 ◽  
pp. 315-315
Author(s):  
Bradley C. Whitmore ◽  
Douglas B. McElroy ◽  
François Schweizer ◽  
Vera C. Rubin
Keyword(s):  
Dark Matter ◽  
Polar Ring ◽  
Ring Galaxies

scholarly journals The anisotropy of the power spectrum in periodic cosmological simulations

2021 ◽  
Vol 503 (4) ◽  
pp. 5638-5645
Author(s):  
Gábor Rácz ◽  
István Szapudi ◽  
István Csabai ◽  
László Dobos
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Initial Conditions ◽  
Power Spectra ◽  
Cosmological Simulations ◽  
Spherical Collapse ◽  
Lower Amplitude ◽  
Hydrodynamical Simulations

ABSTRACT The classical gravitational force on a torus is anisotropic and always lower than Newton’s 1/r2 law. We demonstrate the effects of periodicity in dark matter only N-body simulations of spherical collapse and standard Lambda cold dark matter (ΛCDM) initial conditions. Periodic boundary conditions cause an overall negative and anisotropic bias in cosmological simulations of cosmic structure formation. The lower amplitude of power spectra of small periodic simulations is a consequence of the missing large-scale modes and the equally important smaller periodic forces. The effect is most significant when the largest mildly non-linear scales are comparable to the linear size of the simulation box, as often is the case for high-resolution hydrodynamical simulations. Spherical collapse morphs into a shape similar to an octahedron. The anisotropic growth distorts the large-scale ΛCDM dark matter structures. We introduce the direction-dependent power spectrum invariant under the octahedral group of the simulation volume and show that the results break spherical symmetry.

Dust and infrared imaging of polar ring galaxies

1995 ◽  
Vol 43 (10-11) ◽  
pp. 1377-1388 ◽  
Author(s):  
M. Arnaboldi ◽  
K.C. Freeman ◽  
P.D. Sackett ◽  
L.S. Sparke ◽  
M. Capaccioli
Keyword(s):  
Infrared Imaging ◽  
Polar Ring ◽  
Ring Galaxies

scholarly journals Quantifying tidal stream disruption in a simulated Milky Way

2017 ◽  
Vol 470 (1) ◽  
pp. 522-538 ◽  
Author(s):  
Emily Sandford ◽  
Andreas H. W. Küpper ◽  
Kathryn V. Johnston ◽  
Jürg Diemand
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Galactic Halo ◽  
Mass Range ◽  
Galactic Centre ◽  
High Dimensions ◽  
Density Profiles ◽  
Upper Limits ◽  
Tidal Stream ◽  
Tidal Streams

Abstract Simulations of tidal streams show that close encounters with dark matter subhaloes induce density gaps and distortions in on-sky path along the streams. Accordingly, observing disrupted streams in the Galactic halo would substantiate the hypothesis that dark matter substructure exists there, while in contrast, observing collimated streams with smoothly varying density profiles would place strong upper limits on the number density and mass spectrum of subhaloes. Here, we examine several measures of stellar stream ‘disruption' and their power to distinguish between halo potentials with and without substructure and with different global shapes. We create and evolve a population of 1280 streams on a range of orbits in the Via Lactea II simulation of a Milky Way-like halo, replete with a full mass range of Λcold dark matter subhaloes, and compare it to two control stream populations evolved in smooth spherical and smooth triaxial potentials, respectively. We find that the number of gaps observed in a stellar stream is a poor indicator of the halo potential, but that (i) the thinness of the stream on-sky, (ii) the symmetry of the leading and trailing tails and (iii) the deviation of the tails from a low-order polynomial path on-sky (‘path regularity') distinguish between the three potentials more effectively. We furthermore find that globular cluster streams on low-eccentricity orbits far from the galactic centre (apocentric radius ∼30–80 kpc) are most powerful in distinguishing between the three potentials. If they exist, such streams will shortly be discoverable and mapped in high dimensions with near-future photometric and spectroscopic surveys.

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