Impact of radial migration on stellar and gas radial metallicity distribution

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

doi:10.1093/mnras/stv016

Cited by 71 publications

(59 citation statements)

References 82 publications

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“…compare with observations because our measurements describe possible migration at the current time, whereas the quantity in the simulations refers to the galaxy lifetime and many stars end up on circular orbits after migration. On the other hand, the effect of radial migration is more visible in the scatter of measurements rather that the slope itself (Grand et al 2015). …”

Section: Pne That Deviate From a Pure Rotating Disc Modelmentioning

confidence: 99%

Metallicity gradients in local Universe galaxies: Time evolution and effects of radial migration

Magrini

Coccato²,

Stanghellini

et al. 2016

A&A

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Context. Our knowledge of the shape of radial metallicity gradients in disc galaxies has recently improved. Conversely, the understanding of their time evolution is more complex, since it requires analysis of stellar populations with different ages or systematic studies of galaxies at different redshifts. In the local Universe, H ii regions and planetary nebulae (PNe) are important tools to investigate radial metallicity gradients in disc galaxies. Aims. We present an in-depth study of all nearby spiral galaxies (M33, M31, NGC 300, and M81) with direct-method nebular abundances of both populations, aiming at studying the evolution of their radial metallicity gradients. For the first time, we also evaluate the radial migration of PN populations.Methods. For the selected galaxies, we analysed H ii region and PN properties to: determine whether oxygen in PNe is a reliable tracer for past interstellar medium (ISM) composition; homogenise published datasets; estimate the migration of the oldest stellar populations; and determine the overall chemical enrichment and slope evolution. Results. We confirm that oxygen in PNe is a reliable tracer for past ISM metallicity. We find that PN gradients are flatter than or equal to those of H ii regions. When radial motions are negligible, this result provides a direct measurement of the time evolution of the gradient. For galaxies with dominant radial motions, we provide upper limits on the gradient evolution. Finally, the total metal content increases with time in all target galaxies, and early morphological types have a larger increment Δ(O/H) than late-type galaxies. Conclusions. Our findings provide important constraints to discriminate among different galactic evolutionary scenarios, favouring cosmological models with enhanced feedback from supernovae. The advent of extremely large telescopes allows us to include galaxies in a wider range of morphologies and environments, thus putting firmer constraints on galaxy formation and evolution scenarios.

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Section: Pne That Deviate From a Pure Rotating Disc Modelmentioning

confidence: 99%

Metallicity gradients in local Universe galaxies: Time evolution and effects of radial migration

Magrini

Coccato²,

Stanghellini

et al. 2016

A&A

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“…For generating the initial conditions of our simulations, we use the same technique as in Grand et al (2015). The system consists of a dark matter halo which is treated analytically, and a disc made of gas and stars, which are represented by stellar and gaseous particles.…”

Section: Initial Conditionsmentioning

confidence: 99%

The mass dependence of star formation histories in barred spiral galaxies

Carles¹,

Martel²,

Ellison³

et al. 2016

Mon. Not. R. Astron. Soc.

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We performed a series of 29 gasdynamical simulations of disc galaxies, barred and unbarred, with various stellar masses, to study the impact of the bar on star formation history. Unbarred galaxies evolve very smoothly, with a star formation rate (SFR) that varies by at most a factor of three over a period of 2 Gyr. The evolution of barred galaxies is much more irregular, especially at high stellar masses. In these galaxies, the bar drives a substantial amount of gas toward the centre, resulting in a high SFR, and producing a starburst in the most massive galaxies. Most of the gas is converted into stars, and gas exhaustion leads to a rapid drop of star formation after the starburst. In massive barred galaxies (stellar mass M * > 2 × 10 10 M ⊙ ) the large amount of gas funnelled toward the centre is completely consumed by the starburst, while in lower-mass barred galaxies it is only partially consumed. Gas concentration is thus higher in lower-mass barred galaxies than it is in higher-mass ones. Even though unbarred galaxies funnelled less gas toward their centre, the lower SFR allows this gas to accumulate. At late times, the star formation efficiency is higher in barred galaxies than unbarred ones, enabling these galaxies to maintain a higher SFR with a smaller gas supply. Several properties, such as the global SFR, central SFR, or central gas concentration, vary monotonically with time for unbarred galaxies, but not for barred galaxies. Therefore one must be careful when comparing barred and unbarred galaxies that share one observational property, since these galaxies might be at very different stages of their respective evolution.

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“…In particular, recent simulations have shown that radial migration can induce azimuthal variations of the stellar metallicity distribution (Di Matteo et al 2013;Grand et al 2016). Regarding the gas content, streaming motions along the spiral arms have been found (Grand et al 2015b;Baba et al 2016), which could also produce azimuthal variations of the gas abundance.…”

Section: Introductionmentioning

confidence: 98%

“…Although the causes of radial migration still remain unclear, several simulations have been attempted to understand this important phenomenon in galaxy evolution, finding that both gas and stars might be affected significantly by it (e.g., Minchev et al 2014;Grand et al 2015b). In particular, recent simulations have shown that radial migration can induce azimuthal variations of the stellar metallicity distribution (Di Matteo et al 2013;Grand et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Evidence of Ongoing Radial Migration in NGC 6754: Azimuthal Variations of the Gas Properties

Sánchez-Menguiano

Sánchez

Kawata

et al. 2016

ApJL

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Understanding the nature of spiral structure in disk galaxies is one of the main, and still unsolved, questions in galactic astronomy. However, theoretical works are proposing new testable predictions whose detection is becoming feasible with recent development in instrumentation. In particular, streaming motions along spiral arms are expected to induce azimuthal variations in the chemical composition of a galaxy at a given galactic radius. In this Letter, we analyze the gas content in NGC6754 with VLT/MUSE data to characterize its 2D chemical composition and Hα line of sight velocity distribution. We find that the trailing (leading) edge of the NGC6754 spiral arms show signatures of tangentially slower, radially outward (tangentially faster, radially inward) streaming motions of metal-rich (poor) gas over a large range of radii. These results show direct evidence of gas radial migration for the first time. We compare our results with the gas behavior in an N-body disk simulation showing spiral morphological features rotating with a similar speed as the gas at every radius, in good agreement with the observed trend. This indicates that the spiral arm features in NGC6754 may be transient and rotate similarly as the gas does at a large range of radii.

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Impact of radial migration on stellar and gas radial metallicity distribution

Cited by 71 publications

References 82 publications

Metallicity gradients in local Universe galaxies: Time evolution and effects of radial migration

Metallicity gradients in local Universe galaxies: Time evolution and effects of radial migration

The mass dependence of star formation histories in barred spiral galaxies

Evidence of Ongoing Radial Migration in NGC 6754: Azimuthal Variations of the Gas Properties

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