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The origin of stellar populations in the Galactic bulge from chemical abundances

Matteucci, F. ; Grisoni, V. ; Spitoni, E. ; Zulianello, A. ; Rojas-Arriagada, A. ; Schultheis, M. and Ryde, N. LU (2019) In Monthly Notices of the Royal Astronomical Society 487(4). p.5363-5371
Abstract

In this work, we study the formation and chemical evolution of the Galactic bulge with particular focus on the abundance pattern ([Mg/Fe] versus [Fe/H]), metallicity, and age distribution functions. We consider detailed chemical evolution models for the Galactic bulge and inner disc, with the aim of shedding light on the connection between these components and the origin of bulge stars. In particular, we first present a model assuming a fast and intense star formation, with the majority of bulge stars forming on a time-scale less than 1 Gyr. Then we analyse the possibility of two distinct stellar populations in the bulge, as suggested by Gaia-ESO and APOGEE data. These two populations, one metal poor and the other metal rich, can have... (More)

In this work, we study the formation and chemical evolution of the Galactic bulge with particular focus on the abundance pattern ([Mg/Fe] versus [Fe/H]), metallicity, and age distribution functions. We consider detailed chemical evolution models for the Galactic bulge and inner disc, with the aim of shedding light on the connection between these components and the origin of bulge stars. In particular, we first present a model assuming a fast and intense star formation, with the majority of bulge stars forming on a time-scale less than 1 Gyr. Then we analyse the possibility of two distinct stellar populations in the bulge, as suggested by Gaia-ESO and APOGEE data. These two populations, one metal poor and the other metal rich, can have had two different origins: (i) the metal rich formed after a stop of -250 Myr in the star formation rate of the bulge or (ii) the metal-rich population is made of stars formed in the inner disc and brought into the bulge by the early secular evolution of the bar. We also examine the case of multiple starbursts in the bulge with consequent formation of multiple populations, as suggested by studies of microlensed stars. After comparing model results and observations, we suggest that the most likely scenario is that there are two main stellar populations, both made mainly by old stars (>10 Gyr), with the metal-rich and younger one formed from inner thin disc stars, in agreement with kinematical arguments. However, on the basis of dynamical simulations, we cannot completely exclude that the second population formed after a stop in the star formation during the bulge evolution, so that all the stars formed in situ.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
galaxies: abundances, galaxies: evolution, galaxies: ISM
in
Monthly Notices of the Royal Astronomical Society
volume
487
issue
4
article number
stz1647
pages
9 pages
publisher
Oxford University Press (OUP)
external identifiers
  • scopus:85069484850
ISSN
0035-8711
DOI
10.1093/mnras/stz1647
language
English
LU publication?
yes
id
c6ce9464-8c5e-493b-8c33-db4a4ec237a2
date added to LUP
2019-08-28 10:27:44
date last changed
2019-11-20 05:51:30
@article{c6ce9464-8c5e-493b-8c33-db4a4ec237a2,
  abstract     = {<p>In this work, we study the formation and chemical evolution of the Galactic bulge with particular focus on the abundance pattern ([Mg/Fe] versus [Fe/H]), metallicity, and age distribution functions. We consider detailed chemical evolution models for the Galactic bulge and inner disc, with the aim of shedding light on the connection between these components and the origin of bulge stars. In particular, we first present a model assuming a fast and intense star formation, with the majority of bulge stars forming on a time-scale less than 1 Gyr. Then we analyse the possibility of two distinct stellar populations in the bulge, as suggested by Gaia-ESO and APOGEE data. These two populations, one metal poor and the other metal rich, can have had two different origins: (i) the metal rich formed after a stop of -250 Myr in the star formation rate of the bulge or (ii) the metal-rich population is made of stars formed in the inner disc and brought into the bulge by the early secular evolution of the bar. We also examine the case of multiple starbursts in the bulge with consequent formation of multiple populations, as suggested by studies of microlensed stars. After comparing model results and observations, we suggest that the most likely scenario is that there are two main stellar populations, both made mainly by old stars (&gt;10 Gyr), with the metal-rich and younger one formed from inner thin disc stars, in agreement with kinematical arguments. However, on the basis of dynamical simulations, we cannot completely exclude that the second population formed after a stop in the star formation during the bulge evolution, so that all the stars formed in situ.</p>},
  author       = {Matteucci, F. and Grisoni, V. and Spitoni, E. and Zulianello, A. and Rojas-Arriagada, A. and Schultheis, M. and Ryde, N.},
  issn         = {0035-8711},
  language     = {eng},
  month        = {06},
  number       = {4},
  pages        = {5363--5371},
  publisher    = {Oxford University Press (OUP)},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {The origin of stellar populations in the Galactic bulge from chemical abundances},
  url          = {http://dx.doi.org/10.1093/mnras/stz1647},
  doi          = {10.1093/mnras/stz1647},
  volume       = {487},
  year         = {2019},
}