scholarly journals The formation history of the Milky Way disc with high-resolution cosmological simulations

2021 ◽  
Vol 502 (2) ◽  
pp. 2251-2265
Author(s):  
Marco Giammaria ◽  
Alessandro Spagna ◽  
Mario G Lattanzi ◽  
Giuseppe Murante ◽  
Paola Re Fiorentin ◽  
...  
Keyword(s):  
High Resolution ◽  
Milky Way ◽  
Phase Particle ◽  
Stellar Mass ◽  
Star Formation History ◽  
Origin And Evolution ◽  
Formation History ◽  
Major Merger ◽  
History Of ◽  
Multi Phase

ABSTRACT We analyse from an observational perspective the formation history and kinematics of a Milky Way-like galaxy from a high-resolution zoom-in cosmological simulation that we compare to those of our Galaxy as seen by Gaia DR2 to better understand the origin and evolution of the Galactic thin and thick discs. The cosmological simulation was carried out with the gadget-3 TreePM+SPH code using the MUlti-Phase Particle Integrator (muppi) model. We disentangle the complex overlapping of stellar generations that rises from the top-down and inside-out formation of the galactic disc. We investigate cosmological signatures in the phase-space of mono-age populations and highlight features stemming from past and recent dynamical perturbations. In the simulation, we identify a satellite with a stellar mass of $1.2 \times 10^9~\rm {M}_\odot$, i.e. stellar mass ratio Δ ∼ 5.5 per cent at the time, accreted at z ∼ 1.6, which resembles the major merger Gaia–Sausage–Enceladus that produced the Galactic thick disc, i.e. Δ ∼ 6 per cent. We found at z ∼ 0.5–0.4 two merging satellites with a stellar mass of $8.8 \times 10^8~\rm {M}_\odot$ and $5.1 \times 10^8~\rm {M}_\odot$ that are associated to a strong starburst in the star formation history, which appears fairly similar to that recently found in the solar neighbourhood. Our findings highlight that detailed studies of coeval stellar populations kinematics, which are made available by current and future Gaia data releases and in synergy with simulations, are fundamental to unravel the formation and evolution of the Milky Way discs.

scholarly journals The star formation history of galaxies in 3D: CALIFA perspective

2014 ◽  
Vol 10 (S309) ◽  
pp. 99-104
Author(s):  
R. M. González Delgado ◽  
R. Cid Fernandes ◽  
R. García-Benito ◽  
E. Pérez ◽  
A. L. de Amorim ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Density ◽  
Spectral Synthesis ◽  
Stellar Mass ◽  
Star Formation History ◽  
Chemical Enrichment ◽  
Radial Profiles ◽  
Formation History ◽  
The Galaxy ◽  
History Of

AbstractWe resolve spatially the star formation history of 300 nearby galaxies from the CALIFA integral field survey to investigate: a) the radial structure and gradients of the present stellar populations properties as a function of the Hubble type; and b) the role that plays the galaxy stellar mass and stellar mass surface density in governing the star formation history and metallicity enrichment of spheroids and the disks of galaxies. We apply the fossil record method based on spectral synthesis techniques to recover spatially and temporally resolved maps of stellar population properties of spheroids and spirals with galaxy mass from 109 to 7×1011 M⊙. The individual radial profiles of the stellar mass surface density (μ⋆), stellar extinction (AV), luminosity weighted ages (〈logage〉L), and mass weighted metallicity (〈log Z/Z⊙〉M) are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc and Sd). All these properties show negative gradients as a sight of the inside-out growth of massive galaxies. However, the gradients depend on the Hubble type in different ways. For the same galaxy mass, E and S0 galaxies show the largest inner gradients in μ⋆; and Andromeda-like galaxies (Sb with log M⋆ (M⊙) ∼ 11) show the largest inner age and metallicity gradients. In average, spiral galaxies have a stellar metallicity gradient ∼ −0.1 dex per half-light radius, in agreement with the value estimated for the ionized gas oxygen abundance gradient by CALIFA. A global (M⋆-driven) and local (μ⋆-driven) stellar metallicity relation are derived. We find that in disks, the stellar mass surface density regulates the stellar metallicity; in spheroids, the galaxy stellar mass dominates the physics of star formation and chemical enrichment.

scholarly journals CALIFA survey: The spatially resolved star formation history of massive galaxies

2012 ◽  
Vol 8 (S295) ◽  
pp. 300-303
Author(s):  
Rosa González Delgado ◽  
Enrique Pérez ◽  
Roberto Cid Fernandes ◽  
Rubén García-Benito ◽  
André de Amorim ◽  
...  
Keyword(s):  
Growth Rate ◽  
Star Formation ◽  
Galaxy Evolution ◽  
Local Density ◽  
Spectral Synthesis ◽  
Mass Density ◽  
Stellar Mass ◽  
Star Formation History ◽  
Formation History ◽  
History Of

AbstractThe Calar Alto Legacy Integral Field Area (CALIFA) project is an ongoing 3D spectroscopic survey of 600 nearby galaxies of all kinds. This pioneer survey is providing valuable clues on how galaxies form and evolve. Processed through spectral synthesis techniques, CALIFA datacubes allow us to, for the first time, spatially resolve the star formation history of galaxies spread across the color-magnitude diagram. The richness of this approach is already evident from the results obtained for the first ~ 1/6 of the sample. Here we show how the different galactic spatial sub-components (“bulge” and “disk”) grow their stellar mass over time. We explore the results stacking galaxies in mass bins, finding that, except at the lowest masses, galaxies grow inside-out, and that the growth rate depends on a galaxy's mass. The growth rate of inner and outer regions differ maximally at intermediate masses. We also find a good correlation between the age radial gradient and the stellar mass density, suggesting that the local density is a main driver of galaxy evolution.

The recurrent impact of the Sagittarius dwarf on the star formation history of the Milky Way

2020 ◽  
Vol 4 (10) ◽  
pp. 965-973 ◽  
Author(s):  
Tomás Ruiz-Lara ◽  
Carme Gallart ◽  
Edouard J. Bernard ◽  
Santi Cassisi
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Star Formation History ◽  
Formation History ◽  
History Of

scholarly journals On the recent star formation history of the Milky Way disk

New Astronomy ◽  
2004 ◽  
Vol 9 (6) ◽  
pp. 475-502 ◽  
Author(s):  
R. de la Fuente Marcos ◽  
C. de la Fuente Marcos
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Star Formation History ◽  
Formation History ◽  
History Of

scholarly journals Modeling the kinematics and star formation history of Andromeda II by a gas-rich major merger of dwarf galaxies

2016 ◽  
Vol 11 (S321) ◽  
pp. 132-132
Author(s):  
Sylvain Fouquet ◽  
Ewa L. Łokas ◽  
Andrés del Pino
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Evolutionary Model ◽  
Star Formation History ◽  
Formation History ◽  
Major Merger ◽  
History Of

AbstractWe present an evolutionary model for the origin of Andromeda II, a dwarf spheroidal satellite of M31. The model is an extension of the scenario proposed by Łokas et al. (2014) involving a major merger between two gas-rich disky dwarf galaxies.

scholarly journals Spatial variations in the Milky Way disc metallicity–age relation

2019 ◽  
Vol 489 (2) ◽  
pp. 1742-1752 ◽  
Author(s):  
Diane K Feuillet ◽  
Neige Frankel ◽  
Karin Lind ◽  
Peter M Frinchaboy ◽  
D A García-Hernández ◽  
...  
Keyword(s):  
Milky Way ◽  
Star Formation History ◽  
Chemical Abundance ◽  
Crucial Component ◽  
Stellar Ages ◽  
Formation History ◽  
History Of ◽  
Age Relation ◽  
Age Relations ◽  
Spatial Locations

ABSTRACT Stellar ages are a crucial component to studying the evolution of the Milky Way. Using Gaia DR2 distance estimates, it is now possible to estimate stellar ages for a larger volume of evolved stars through isochrone matching. This work presents [M/H]–age and [α/M]–age relations derived for different spatial locations in the Milky Way disc. These relations are derived by hierarchically modelling the star formation history of stars within a given chemical abundance bin. For the first time, we directly observe that significant variation is apparent in the [M/H]–age relation as a function of both Galactocentric radius and distance from the disc mid-plane. The [M/H]–age relations support claims that radial migration has a significant effect in the plane of the disc. Using the [M/H] bin with the youngest mean age at each radial zone in the plane of the disc, the present-day metallicity gradient is measured to be −0.059 ± 0.010 dex kpc−1, in agreement with Cepheids and young field stars. We find a vertically flared distribution of young stars in the outer disc, confirming predictions of models and previous observations. The mean age of the [M/H]–[α/M] distribution of the solar neighbourhood suggests that the high-[M/H] stars are not an evolutionary extension of the low-α sequence. Our observational results are important constraints to Galactic simulations and models of chemical evolution.

scholarly journals A ‘Universal’ Density Profile for the Outer Stellar Halos of Galaxies

2016 ◽  
Vol 11 (S321) ◽  
pp. 84-86
Author(s):  
Rhea-Silvia Remus ◽  
Andreas Burkert ◽  
Klaus Dolag
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Total Mass ◽  
Milky Way ◽  
Mass Range ◽  
Density Profiles ◽  
Formation History ◽  
Stellar Halo ◽  
History Of ◽  
Free Parameters

AbstractThe outer stellar halos of galaxies contain vital information about the formation history of galaxies, since the relaxation timescales in the outskirts are long enough to keep the memory, while the information about individual formation events in the central parts has long been lost due to mixing, star formation and relaxation. To unveil some of the information encoded in these faint outer halo regions, we study the stellar outskirts of galaxies selected from a fully hydrodynamical high-resolution cosmological simulation, called Magneticum. We find that the density profiles of the outer stellar halos of galaxies over a broad mass range can be well described by an Einasto profile. For a fixed total mass range, the free parameters of the Einasto fits are closely correlated. Galaxies which had more (dry) merger events tend to have lesser curved outer stellar halos, however, we find no indication that the amount of curvature is correlated with galaxy morphology. The Einasto-like shape of the outer stellar halo densities can also explain the observed differences between the Milky Way and Andromeda outer stellar halos.

scholarly journals Reconstructing the star formation history of the Milky Way disc(s) from chemical abundances

2015 ◽  
Vol 578 ◽  
pp. A87 ◽  
Author(s):  
O. Snaith ◽  
M. Haywood ◽  
P. Di Matteo ◽  
M. D. Lehnert ◽  
F. Combes ◽  
...  
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Star Formation History ◽  
Chemical Abundances ◽  
Formation History ◽  
History Of
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