The dynamics of stars around spiral arms

Grand, Robert J. J.; Kawata, Daisuke; Cropper, Mark

doi:10.1111/j.1365-2966.2012.20411.x

Cited by 181 publications

(209 citation statements)

References 47 publications

Supporting

Mentioning

185

Contrasting

Order By: Relevance

“…They show clearly in their simulations that the radial migration acts to maintain the negative radial metallicity gradient but significantly broadens the metallicity distribution at every radius by about 0.8 dex (see Figure 2 in Grand & Kawata 2015). The motion of star clusters in spiral arms and the angular momentum exchange is similar to that of stars investigated in simulations of stellar discs (Fujii & Baba 2012;Grand et al 2012).…”

Section: Computation Of Oc Birth-sitesmentioning

confidence: 69%

The evolution of the Milky Way: new insights from open clusters

Reddy¹,

Lambert²,

Giridhar³

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We have collected high-dispersion echelle spectra of red giant members in the twelve open clusters (OCs) and derived stellar parameters and chemical abundances for 26 species by either line equivalent widths or synthetic spectrum analyses. We confirm the lack of an age−metallicity relation for OCs but argue that such a lack of trend for OCs arise from the limited coverage in metallicity compared to that of field stars which span a wide range in metallicity and age. We confirm that the radial metallicity gradient of OCs is steeper (flatter) for R gc < 12 kpc (>12 kpc). We demonstrate that the sample of clusters constituting a steep radial metallicity gradient of slope −0.052±0.011 dex kpc −1 at R gc < 12 kpc are younger than 1.5 Gyr and located close to the Galactic midplane (| z| < 0.5 kpc) with kinematics typical of the thin disc. Whereas the clusters describing a shallow slope of −0.015±0.007 dex kpc −1 at R gc > 12 kpc are relatively old, thick disc members with a striking spread in age and height above the midplane (0.5 < | z| < 2.5 kpc). Our investigation reveals that the OCs and field stars yield consistent radial metallicity gradients if the comparison is limited to samples drawn from the similar vertical heights. We argue via the computation of Galactic orbits that all the outer disc clusters were actually born inward of 12 kpc but the orbital eccentricity has taken them to present locations very far from their birthplaces.

show abstract

Section: Computation Of Oc Birth-sitesmentioning

confidence: 69%

The evolution of the Milky Way: new insights from open clusters

Reddy¹,

Lambert²,

Giridhar³

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…On the other hand, the power spectrum of simulation G13F (and to an extent G14) shows evidence of a turnover in power on scales of k ∼ 0.4 km s −1 , which is the characteristic feature of the observed power spectrum. Therefore, it is possible that the main features of the observed power spectrum can be explained purely by the systematic stellar motion induced by co-rotating spiral arms seen in simulations (e.g., Grand et al 2012aGrand et al ,b, 2014. We note that this study is limited to our current set of simulations, and we have not extensively searched for a N -body simulation model with transient spiral arms only that can better reproduce the observed power spectrum.…”

Section: Resultsmentioning

confidence: 99%

Spiral- and bar-driven peculiar velocities in Milky Way-sized galaxy simulations

Grand

Bovy

Kawata

et al. 2015

Mon. Not. R. Astron. Soc.

Self Cite

View full text Add to dashboard Cite

We investigate the kinematic signatures induced by spiral and bar structure in a set of simulations of Milky Way-sized spiral disc galaxies. The set includes test particle simulations that follow a quasi-stationary density wave-like scenario with rigidly rotating spiral arms, and N -body simulations that host a bar and transient, co-rotating spiral arms. From a location similar to that of the Sun, we calculate the radial, tangential and line-of-sight peculiar velocity fields of a patch of the disc and quantify the fluctuations by computing the power spectrum from a two-dimensional Fourier transform. We find that the peculiar velocity power spectrum of the simulation with a bar and transient, co-rotating spiral arms fits very well to that of APOGEE red clump star data, while the quasi-stationary density wave spiral model without a bar does not. We determine that the power spectrum is sensitive to the number of spiral arms, spiral arm pitch angle and position with respect to the spiral arm. However, it is necessary to go beyond the line of sight velocity field in order to distinguish fully between the various spiral models with this method. We compute the power spectrum for different regions of the spiral discs, and discuss the application of this analysis technique to external galaxies.

show abstract

“…It was not until the work by Sellwood & Binney (2002) that radial migration was established as an important process affecting the entire disc, where stars shift guiding radii due to interaction with transient spiral structure. A number of works using N-body and N-body/SPH simulations (e.g., Grand et al 2012;Minchev et al 2011;Roškar et al 2008) have confirmed that migration always takes place in numerical galactic discs.…”

Section: Radial Migrationmentioning

confidence: 99%

Constraining the Milky Way assembly history with Galactic Archaeology

Minchev

2016

Astron Nachr

View full text Add to dashboard Cite

The aim of Galactic Archaeology is to recover the evolutionary history of the Milky Way from its present day kinematical and chemical state. Because stars move away from their birth sites, the current dynamical information alone is not sufficient for this task. The chemical composition of stellar atmospheres, on the other hand, is largely preserved over the stellar lifetime and, together with accurate ages, can be used to recover the birthplaces of stars currently found at the same Galactic radius. In addition to the availability of large stellar samples with accurate 6D kinematics and chemical abundance measurements, this requires detailed modeling with both dynamical and chemical evolution taken into account. An important first step is to understand the variety of dynamical processes that can take place in the Milky Way, including the perturbative effects of both internal (bar and spiral structure) and external (infalling satellites) agents. We discuss here (1) how to constrain the Galactic bar, spiral structure, and merging satellites by their effect on the local and global disc phase-space, (2) the effect of multiple patterns on the disc dynamics, and (3) the importance of radial migration and merger perturbations for the formation of the Galactic thick disc. Finally, we discuss the construction of Milky Way chemo-dynamical models and relate to observations.

show abstract

The dynamics of stars around spiral arms

Cited by 181 publications

References 47 publications

The evolution of the Milky Way: new insights from open clusters

The evolution of the Milky Way: new insights from open clusters

Spiral- and bar-driven peculiar velocities in Milky Way-sized galaxy simulations

Constraining the Milky Way assembly history with Galactic Archaeology

Contact Info

Product

Resources

About