scholarly journals Role of Gaseous Disk in the Formation of the Spiral Structure of the Milky Way Galaxy

2016 ◽  
Vol 25 (4) ◽  
Author(s):  
V. I. Korchagin ◽  
S. A. Khoperskov ◽  
A. V. Khoperskov
Keyword(s):  
Milky Way ◽  
Spiral Structure ◽  
Stellar Disk ◽  
Milky Way Galaxy ◽  
Density Distributions ◽  
Disk Rotation ◽  
Gaseous Component ◽  
Axisymmetric Structure ◽  
Stellar Density

AbstractWe use observational gaseous and stellar density distributions in the disk of the Milky Way (MW) galaxy together with the disk rotation curve and measured disk velocity dispersion to build collisionless and combined collisionless-gaseous equilibrium models of the Milky Way disk. A purely collisionless MW disk is unstable towards the development of a central bar, so that during the nonlinear stage of instability the stellar bar is a dominant non-axisymmetric structure developing the disk. A ten percent admixture of a gaseous component leads to the development of a three-armed spiral structure in the stellar disk, decoupled spatially from the central bar-like structure. In our simulations, the spiral structure lasts for about 3 Gyr.

scholarly journals Modeling of Spiral Structure in a Multi-Component Milky Way-Like Galaxy

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 29
Author(s):  
Sergey Khrapov ◽  
Alexander Khoperskov ◽  
Vladimir Korchagin
Keyword(s):  
Milky Way ◽  
Spiral Structure ◽  
Gravitational Interaction ◽  
Equations Of Motion ◽  
Milky Way Galaxy ◽  
Density Distributions ◽  
Maximum Value ◽  
Central Regions ◽  
Axis Length ◽  
Bar Formation

Using recent observational data, we construct a set of multi-component equilibrium models of the disk of a Milky Way-like galaxy. The disk dynamics are studied using collisionless-gaseous numerical simulations, based on the joined integration of the equations of motion for the collision-less particles using direct integration of gravitational interaction and the gaseous SPH-particles. We find that after approximately one Gyr, a prominent central bar is formed having a semi-axis length of about three kpc, together with a multi-armed spiral pattern represented by a superposition of m= 2-, 3-, and 4-armed spirals. The spiral structure and the bar exist for at least 3 Gyr in our simulations. The existence of the Milky Way bar imposes limitations on the density distributions in the subsystems of the Milky Way galaxy. We find that a bar does not form if the radial scale length of the density distribution in the disk exceeds 2.6 kpc. As expected, the bar formation is also suppressed by a compact massive stellar bulge. We also demonstrate that the maximum value in the rotation curve of the disk of the Milky Way galaxy, as found in its central regions, is explained by non-circular motion due to the presence of a bar and its orientation relative to an observer.

scholarly journals The spiral structure of our Milky Way Galaxy

2009 ◽  
Vol 499 (2) ◽  
pp. 473-482 ◽  
Author(s):  
L. G. Hou ◽  
J. L. Han ◽  
W. B. Shi
Keyword(s):  
Milky Way ◽  
Spiral Structure ◽  
Milky Way Galaxy

scholarly journals On the spiral structure of the Milky Way Galaxy

2011 ◽  
Vol 55 (2) ◽  
pp. 108-122 ◽  
Author(s):  
Yu. N. Efremov
Keyword(s):  
Milky Way ◽  
Spiral Structure ◽  
Milky Way Galaxy

Galactoseismology in the Age of Gaia

2017 ◽  
Vol 13 (S334) ◽  
pp. 189-194
Author(s):  
Lawrence M. Widrow ◽  
Matthew H. Chequers
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Spiral Structure ◽  
Dwarf Galaxy ◽  
Matter Density ◽  
Observational Evidence ◽  
Time Dependent ◽  
Stellar Disk ◽  
Vertical Force ◽  
Bending Waves

AbstractRecent observations from SEGUE, RAVE, and LAMOST have revealed tantalizing evidence that the local stellar disk of the Milky Way is in a state of disequilibrium. In particular, the disk appears to exhibit bending and breathing waves normal to its midplane within 2 kiloparsecs of our position within the disk. There also appear to be bending waves or corrugations at larger Galactocentric radii. These waves may be linked to other time-dependent disk phenomena such as the bar, spiral structure, and warp, or they may be the result of a passing dark matter subhalo or dwarf galaxy. Here, we discuss the observational evidence for these waves, the theory of bending and breathing waves in (simulated) stellar disks, and implications of disequilibrium for attempts to determine the local vertical force and dark matter density (the Oort problem). We also discuss the types of analyses that one might do with the Gaia database.

scholarly journals Spiral structure of the Milky Way and external galaxies

1985 ◽  
Vol 106 ◽  
pp. 255-272 ◽  
Author(s):  
Debra Meloy Elmegreen
Keyword(s):  
Milky Way ◽  
Spiral Structure ◽  
Vantage Point ◽  
Milky Way Galaxy ◽  
External Galaxies ◽  
Insight Into

The spiral structure of the Milky Way galaxy has always been somewhat elusive because of our internal vantage point. This review will present methods and data for determining the overall pattern, and will summarize various models that have been proposed. Observations of spirals in external galaxies will also be discussed, because they can provide insight into the spiral structure of the Milky Way.

A Star Is Born

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Milky Way ◽  
Rotating Disk ◽  
Stellar Disk ◽  
Mass Star ◽  
Fine Dust ◽  
Solar Mass ◽  
Milky Way Galaxy ◽  
Supermassive Black Hole ◽  
The Galaxy ◽  
Main Component

This chapter focuses on the nature and composition of the Milky Way galaxy. The main component of the Milky Way is a rotating disk of stars some 100,000 light-years across but only about 1,000 light-years thick. Between the stars lies an extremely tenuous mixture of gas and fine dust grains called the interstellar medium. The disk of stars is only about 1,000 light-years thick but becomes thicker near the Milky Way's center, where a bar-shaped bulge of densely packed stars surrounds a supermassive black hole at the heart of the galaxy. Enveloping the thin stellar disk is an extended disk of gas about 10 times thicker. Today, stars are forming in the Milky Way at a rate equivalent to one solar-mass star every year. Judging by the age of its oldest members, the Milky Way has been giving birth to new stars for over 13 billion years.

scholarly journals Disk stars in the Milky Way detected beyond 25 kpc from its center

2018 ◽  
Vol 612 ◽  
pp. L8 ◽  
Author(s):  
M. López-Corredoira ◽  
C. Allende Prieto ◽  
F. Garzón ◽  
H. Wang ◽  
C. Liu ◽  
...  
Keyword(s):  
Milky Way ◽  
Galactic Plane ◽  
Maximum Size ◽  
Maximum Distance ◽  
Stellar Disk ◽  
Stellar Density ◽  
Metallicity Distribution

Context. The maximum size of the Galactic stellar disk is not yet known. Some studies have suggested an abrupt drop-off of the stellar density of the disk at Galactocentric distances R ≳ 15 kpc, which means that in practice no disk stars or only very few of them should be found beyond this limit. However, stars in the Milky Way plane are detected at larger distances. In addition to the halo component, star counts have placed the end of the disk beyond 20 kpc, although this has not been spectroscopically confirmed so far. Aims. Here, we aim to spectroscopically confirm the presence of the disk stars up to much larger distances. Methods. With data from the LAMOST and SDSS-APOGEE spectroscopic surveys, we statistically derived the maximum distance at which the metallicity distribution of stars in the Galactic plane is distinct from that of the halo populations. Results. Our analysis reveals the presence of disk stars at R > 26 kpc (99.7% C.L.) and even at R > 31 kpc (95.4% C.L.).

scholarly journals How does the stellar disk of the Milky Way get its gas?

2017 ◽  
Vol 13 (S334) ◽  
pp. 219-222
Author(s):  
Sebastián E. Nuza ◽  
Cristina Chiappini ◽  
Cecilia Scannapieco ◽  
Ivan Minchev ◽  
Marie Martig ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Milky Way ◽  
Thin Disk ◽  
Stellar Disk ◽  
Galactocentric Distance ◽  
Chemical Abundances ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
History Of ◽  
Inside Out

AbstractIn chemodynamical evolution models it is usually assumed that the Milky Way galaxy forms from the inside-out implying that gas inflows onto the disk decrease with galactocentric distance. Similarly, to reproduce differences between chemical abundances of the thick disk and bulge with respect to those of the thin disk, higher accretion fluxes at early times are postulated. By using a suite of Milky Way-like galaxies extracted from cosmological simulations, we investigate the accretion of gas on the simulated stellar disks during their whole evolution. In general, we find that the picture outlined above holds, although the detailed behavior depends on the assembly history of the Galaxy and the complexities inherent to the physics of galaxy formation.

The Long View of Planetary Systems

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Planetary Systems ◽  
Giant Planets ◽  
Milky Way Galaxy ◽  
Population Statistics ◽  
The Past ◽  
General Terms ◽  
The Galaxy ◽  
The Universe

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.

scholarly journals The role of faint population III supernovae in forming CEMP stars in ultra-faint dwarf galaxies

2021 ◽  
Author(s):  
Myoungwon Jeon ◽  
Volker Bromm ◽  
Gurtina Besla ◽  
Jinmi Yoon ◽  
Yumi Choi
Keyword(s):  
Milky Way ◽  
Dwarf Galaxies ◽  
Mass Resolution ◽  
Explosion Energy ◽  
High Carbon ◽  
Cosmological Simulations ◽  
Carbon Abundance ◽  
The Absolute ◽  
Zoom In

Abstract CEMP-no stars, a subset of carbon enhanced metal poor (CEMP) stars ($\rm [C/Fe]\ge 0.7$ and $\rm [Fe/H]\lesssim -1$) have been discovered in ultra-faint dwarf (UFD) galaxies, with Mvir ≈ 108 M⊙ and M* ≈ 103 − 104 M⊙ at z = 0, as well as in the halo of the Milky Way (MW). These CEMP-no stars are local fossils that may reflect the properties of the first (Pop III) and second (Pop II) generation of stars. However, cosmological simulations have struggled to reproduce the observed level of carbon enhancement of the known CEMP-no stars. Here we present new cosmological hydrodynamic zoom-in simulations of isolated UFDs that achieve a gas mass resolution of mgas ≈ 60 M⊙. We include enrichment from Pop III faint supernovae (SNe), with ESN = 0.6 × 1051 erg, to understand the origin of CEMP-no stars. We confirm that Pop III and Pop II stars are mainly responsible for the formation of CEMP and C-normal stars respectively. New to this study, we find that a majority of CEMP-no stars in the observed UFDs and the MW halo can be explained by Pop III SNe with normal explosion energy (ESN = 1.2 × 1051 erg) and Pop II enrichment, but faint SNe might also be needed to produce CEMP-no stars with $\rm [C/Fe]\gtrsim 2$, corresponding to the absolute carbon abundance of $\rm A(C)\gtrsim 6.0$. Furthermore, we find that while we create CEMP-no stars with high carbon ratio $\rm [C/Fe]\approx 3-4$, by adopting faint SNe, it is still challenging to reproduce CEMP-no stars with extreme level of carbon abundance of $\rm A(C)\approx 7.0-7.5$, observed both in the MW halo and UFDs.

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