scholarly journals Internal Kinematics of Modelled Isolated and Interacting Disc Galaxies

2006 ◽  
Vol 2 (S235) ◽  
pp. 216-216
Author(s):  
T. Kronberger ◽  
W. Kapferer ◽  
S. Schindler ◽  
A. Böhm ◽  
E. Kutdemir ◽  
...  
Keyword(s):  
Velocity Field ◽  
Spiral Galaxies ◽  
Rotation Velocity ◽  
Systematic Investigation ◽  
Velocity Fields ◽  
The Galaxy ◽  
History Of ◽  
Hydrodynamical Simulations ◽  
Interaction History ◽  
Disc Galaxies

AbstractWe present a systematic investigation of the velocity fields of both isolated and interacting spiral galaxies in combined N-body/hydrodynamical simulations. Closely mimicking the procedures applied in observations of distant, small, and faint galaxies we extract rotation curves (RCs) and compare the results of the simulation directly to observations. Irregularities in the velocity field reflect disturbances in the gravitational potential of the galaxy. They can be used to trace the recent interaction history of a galaxy and give possible clues to the type of the respective interaction. In addition, identifying disturbances in the RCs is important for Tully-Fisher studies in order to accurately derive the maximum rotation velocity.

NIHAO-UHD: High-resolution Simulations of MW mass galaxies

2017 ◽  
Vol 13 (S334) ◽  
pp. 209-212
Author(s):  
Tobias Buck ◽  
Andrea Macciò ◽  
Melissa Ness ◽  
Aura Obreja ◽  
Aaron Dutton
Keyword(s):  
High Resolution ◽  
Milky Way ◽  
Satellite System ◽  
The Galaxy ◽  
First Results ◽  
History Of ◽  
Galaxy Center ◽  
Hydrodynamical Simulations ◽  
Very High ◽  
Disc Galaxies

AbstractHigh resolution cosmological and hydrodynamical simulations have reached a resolution able to resolve in a self consistent way the disc of our galaxy, the galaxy center and the satellites orbiting around it. We present first results from the NIHAO-UHD project, a set of very high-resolution baryonic zoom-in simulations of Milky Way mass disc galaxies. These simulations model the full cosmological assembly history of the galaxies and their satellite system using the same, well tested physics as the NIHAO project. We show that these simulations can self-consistently reproduce the observed kinematical and morphological features of the X-shaped bulge observed in our own Milky Way.

scholarly journals How well do we know the rotation curve of our Galaxy?

1985 ◽  
Vol 106 ◽  
pp. 107-108
Author(s):  
Paris Pişmiş
Keyword(s):  
Velocity Field ◽  
Rotation Curve ◽  
Spiral Galaxies ◽  
Spiral Structure ◽  
Smooth Curve ◽  
Velocity Fields ◽  
Rotation Curves ◽  
The Past ◽  
Different Populations ◽  
The Waves

The existence of variations from a smooth curve, in the form of waves, in the rotation curves of galaxies was pointed out earlier, and an interpretation was proposed based on the argument that the waves were the manifestation of the coexistence of different populations in a galaxy (see for example PişLmiş 1965, 1974). Observations in the past few years have shown that “undulations” in the rotation curve of spiral galaxies are rather common phenomena; maxima and minima occur roughly at arm and interarm regions, respectively. The velocity fields of the majority of the 23 galaxies compiled by Bosma (1978) exhibit well-defined waves. In particular the velocity field in the 21-cm HI line of M81 by Visser shows clearly the correlation of the waves with the spiral structure.

scholarly journals HII Regions of NGC 628 and M101 as seen with SpIOMM

2010 ◽  
Vol 6 (S277) ◽  
pp. 112-115 ◽  
Author(s):  
Laurie Rousseau-Nepton ◽  
Carmelle Robert ◽  
Laurent Drissen
Keyword(s):  
Spiral Galaxies ◽  
Hii Regions ◽  
Stellar Populations ◽  
Emission Lines ◽  
Visible Range ◽  
Star Forming ◽  
The Galaxy ◽  
History Of

AbstractWith SpIOMM, we obtained numerous spectra in the visible range covering simultaneously several emission lines of bright Hii regions in the spiral galaxies NGC 628 and M101. We measured the size and luminosity of the Hii regions as well as the gas metallicity, temperature, and density. We estimated the age and star forming rate of the young stellar populations associated with the Hii regions. We looked for gradients along the galaxy radius and search for relations with the galactic arm positions. This is a first step in a project, based on a detailed study of stellar populations, to rebuild the history of spiral galaxies and to identify the mechanisms responsible for their evolution.

scholarly journals Stellar substructures in the periphery of the magellanic clouds with the VISTA hemisphere survey from the red clump and other tracers

2021 ◽  
Author(s):  
Dalal El Youssoufi ◽  
Maria-Rosa L Cioni ◽  
Cameron P M Bell ◽  
Richard de Grijs ◽  
Martin A T Groenewegen ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Magellanic Clouds ◽  
Imaging Data ◽  
The North ◽  
The Galaxy ◽  
History Of ◽  
Northern Side ◽  
Red Clump ◽  
Interaction History

Abstract We study the morphology of the stellar periphery of the Magellanic Clouds in search of substructure using near–infrared imaging data from the VISTA Hemisphere Survey (VHS). Based on the selection of different stellar populations using the (J − Ks, Ks) colour–magnitude diagram, we confirm the presence of substructures related to the interaction history of the Clouds and find new substructures on the eastern side of the LMC disc which may be owing to the influence of the Milky Way, and on the northern side of the SMC, which is probably associated to the ellipsoidal structure of the galaxy. We also study the luminosity function of red clump stars in the SMC and confirm the presence of a bi–modal distance distribution, in the form of a foreground population. We find that this bi–modality is still detectable in the eastern regions of the galaxy out to a 10○ distance from its centre. Additionally, a background structure is detected in the North between 7○ and 10○ from the centre which might belong to the Counter Bridge, and a foreground structure is detected in the South between 6○ and 8○ from the centre which might be linked to the Old Bridge.

scholarly journals Assembling Spiral Galaxies

1996 ◽  
Vol 171 ◽  
pp. 11-18
Author(s):  
R.C. Kennicutt
Keyword(s):  
Galaxy Formation ◽  
Spiral Galaxies ◽  
Dynamical Evolution ◽  
Star Formation History ◽  
Physical Mechanisms ◽  
Hubble Sequence ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
History Of ◽  
Formation And Evolution

Nearby spiral galaxies offer vital clues to some of the most fundamental questions about galaxy formation and evolution: What is the star formation history of the universe, past and future? When did disks form, during the final stages of a single primeval collapse, or as a continuous or episodic process? What is the evolutionary nature of the Hubble sequence, and what are the physical mechanisms that dictate the present-day Hubble type of a galaxy? Was Hubble type imprinted at birth, or can it be deterined or at least modified by infall, mergers, or secular dynamical evolution within the galaxy? These issues are not specific to spirals, of course, and much of this conference will address just these questions in a broader context. However present-day spirals offer unique advantages for studying these problems; they exhibit a broad range of dynamical and evolutionary properties, and the dynamical fragility of disks makes them excellent seismometers of galaxy interaction and merger rates at recent epochs.

scholarly journals Galactic spiral generation in tidal encounters

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
Alex R. Pettitt ◽  
Elizabeth J. Tasker ◽  
James W. Wadsley
Keyword(s):  
Spiral Galaxies ◽  
Key Points ◽  
The Galaxy ◽  
Grand Design ◽  
Spiral Structures ◽  
Galactic Spiral ◽  
Morphological Differences ◽  
The Universe ◽  
Disc Galaxies ◽  
Real Universe

AbstractThe existence of grand design spiral galaxies in the universe is still a standing problem. The passage of a small companion is known to be able to induce spiral structures in disc galaxies, but there remains questions over how relevant this mechanism is to the galaxies observed in the real universe. Our study aims to address two key points regarding such interactions; the limiting mass companion needed to drive tidal spiral structures, and the differences between the resulting gas and stellar morphology. We find the minimum mass of a companion to be as low as 5% of the stellar mass of the galaxy, and that the arms formed in the gas and the stars display very minor dynamical and morphological differences.

scholarly journals The effect of AGN feedback on Sunyaev-Zeldovich properties of simulated galaxy clusters

2016 ◽  
Vol 12 (S324) ◽  
pp. 237-238
Author(s):  
Dunja Fabjan ◽  
S. Planelles ◽  
S. Borgani ◽  
G. Murante ◽  
E. Rasia ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Clusters ◽  
State Of The Art ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Stellar Feedback ◽  
The Galaxy ◽  
History Of ◽  
Hydrodynamical Simulations ◽  
Massive Clusters

AbstractWe studied the imprints that feedback from Active Galactic Nuclei (AGN) leaves on the intracluster plasma during the assembly history of galaxy clusters. To this purpose we used state-of-the-art cosmological hydrodynamical simulations based on an updated version of the Tree-PM SPH GADGET-3 code, comparing three sets of simulations with different prescriptions for the physics of baryons (including AGN and/or stellar feedback). We explore the effect of these different physics, in particular AGN feedback, on IntraCluster medium (ICM) properties observed via Sunyaev-Zel’dovich (SZ) effect using an extended set of galaxy clusters (~100 clusters with M500 masses above 5 × 1013M⊙/h). Some of the main findings are that the scaling relation between the integrated SZ flux and the galaxy cluster total mass is in good accordance with several observed samples, especially for massive clusters, and does not show any clear redshift evolution, with the slope of the relation close to the theoretical one in the AGN feedback case. As for the scatter of this relation, we obtain a mild dependence on the cluster dynamical state.

scholarly journals On Non-Spherical Models for Spiral Galaxy Gravitation Potential Yielding Flat Rotation Curve

2021 ◽  
Author(s):  
Swagatam Sen
Keyword(s):  
Spiral Galaxies ◽  
Galactic Plane ◽  
Rotation Velocity ◽  
Radial Symmetry ◽  
Galactic Centre ◽  
Spherically Symmetric ◽  
Annular Disk ◽  
Spherical Models ◽  
The Galaxy ◽  
Flat Rotation Curve

Abstract A two component model of gravitation potential for spiral galaxies has been proposed which couples a spherically symmetric component with a second component that observes planar radial symmetry on the galactic plane and vanishes outside an annular disk beyond the edge of galaxy's effective radius. It is shown that such a model for potential satisfying Poisson Equation would produce rotation velocity curve towards the edge of the galaxy which is flat over distance from the galactic centre. This relationship, which is experimentally observed in many spiral galaxies, is shown as a consequence of classical understanding of gravity and specific symmetry of the gravitational potential without any extrinsic requirement of dark matter. It is also demonstrated that this potential directly yields a relationship between inner mass of the galaxy and terminal rotation velocity, which has been empirically observed and known as Baryonic Tully-Fisher relations. Furthermore a direct test has been proposed for experimental verification of the proposed theory.

scholarly journals A Derivation of Flat Rotation Curve of Spiral Galaxies and Baryonic Tully-Fisher Relation

2020 ◽  
Author(s):  
Swagatam Sen
Keyword(s):  
Laplace Equation ◽  
Spiral Galaxy ◽  
Rotation Curve ◽  
Spiral Galaxies ◽  
Rotation Velocity ◽  
Alternative Solution ◽  
The Galaxy ◽  
Flat Rotation Curve ◽  
Disc Region ◽  
Fisher Relation

Fundamentally for the extended disc region of a spiral galaxy, an alternative solution to Laplace equation has been presented for a potential that is radially symmetric on the disc plane. This potential, unlike newtonian one, is shown to be logarithmic in distance from the centre, which allows for the rotation velocity to be constant along the disc radius.It is also shown that this potential easily manifests into a relationship between inner mass of the galaxy and terminal rotation velocity, which has been empirically observed and known as Baryonic Tully-Fisher relations.

scholarly journals Distant Galaxy Transformation Probed by VLT and HST

2006 ◽  
Vol 2 (S235) ◽  
pp. 258-258
Author(s):  
B. L. Ziegler ◽  
E. Kutdemir ◽  
A. Böhm ◽  
K. Jäger ◽  
M. Verdugo ◽  
...  
Keyword(s):  
Velocity Field ◽  
Mass Distribution ◽  
Spiral Galaxies ◽  
Structural Parameters ◽  
Stellar Populations ◽  
Velocity Fields ◽  
Rotation Curves ◽  
Distant Galaxy ◽  
Interaction Processes ◽  
Transformation Mechanisms

AbstractWe investigate the morphologies and velocity fields of spiral galaxies in distant clusters (z ~ 0.5) focussing on signatures from interactions. Structural parameters and peculiarities are determined with HST/ACS images. To derive the internal kinematics and rotation curves we have performed 3D–spectroscopy allowing the construction of the full velocity field for each galaxy. Combining both approaches, transformation mechanisms are revealed that affect not only the stellar populations but also the mass distribution. The observations are supported by N-body/SPH simulations of different interaction processes.

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