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The Gaia -ESO Survey : The N/O abundance ratio in the Milky Way?

Magrini, L.; Vincenzo, F.; Randich, S.; Pancino, E.; Casali, G.; Tautvaišien, G.; Drazdauskas, A.; Mikolaitis, S.; Minkevičiūt, R. and Stonkut, E., et al. (2018) In Astronomy and Astrophysics 618.
Abstract

Context. The abundance ratio N/O is a useful tool to study the interplay of galactic processes, for example star formation e ciency, timescale of infall, and outflow loading factor. Aims. We aim to trace log(N/O) versus [Fe/H] in the Milky Way and to compare this ratio with a set of chemical evolution models to understand the role of infall, outflow, and star formation e ciency in the building up of the Galactic disc. Methods. We used the abundances from IDR2-3, IDR4, IDR5 data releases of the Gaia-ESO Survey both for Galactic field and open cluster stars. We determined membership and average composition of open clusters and we separated thin and thick disc field stars. We considered the e ect of mixing in the abundance of N in giant... (More)

Context. The abundance ratio N/O is a useful tool to study the interplay of galactic processes, for example star formation e ciency, timescale of infall, and outflow loading factor. Aims. We aim to trace log(N/O) versus [Fe/H] in the Milky Way and to compare this ratio with a set of chemical evolution models to understand the role of infall, outflow, and star formation e ciency in the building up of the Galactic disc. Methods. We used the abundances from IDR2-3, IDR4, IDR5 data releases of the Gaia-ESO Survey both for Galactic field and open cluster stars. We determined membership and average composition of open clusters and we separated thin and thick disc field stars. We considered the e ect of mixing in the abundance of N in giant stars. We computed a grid of chemical evolution models, suited to reproduce the main features of our Galaxy, exploring the e ects of the star formation e ciency, infall timescale, and di erential outflow. Results. With our samples, we map the metallicity range0:6 [Fe/H] 0.3 with a corresponding1:2 log(N/O) 0:2, where the secondary production of N dominates. Thanks to the wide range of Galactocentric distances covered by our samples, we can distinguish the behaviour of log(N/O) in di erent parts of the Galaxy. Conclusions. Our spatially resolved results allow us to distinguish di erences in the evolution of N/O with Galactocentric radius. Comparing the data with our models, we can characterise the radial regions of our Galaxy. A shorter infall timescale is needed in the inner regions, while the outer regions need a longer infall timescale, coupled with a higher star formation e ciency. We compare our results with nebular abundances obtained in MaNGA galaxies, finding in our Galaxy a much wider range of log(N/O) than in integrated observations of external galaxies of similar stellar mass, but similar to the ranges found in studies of individual H II regions.

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keywords
Galaxy: abundances, Galaxy: disk, Open clusters and associations: general
in
Astronomy and Astrophysics
volume
618
publisher
EDP Sciences
external identifiers
  • scopus:85056145632
ISSN
0004-6361
DOI
10.1051/0004-6361/201833224
language
English
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yes
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ba247ae8-1f6f-48d8-87cc-dc20a9f4d9b7
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2018-11-22 14:18:10
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@article{ba247ae8-1f6f-48d8-87cc-dc20a9f4d9b7,
  abstract     = {<p>Context. The abundance ratio N/O is a useful tool to study the interplay of galactic processes, for example star formation e ciency, timescale of infall, and outflow loading factor. Aims. We aim to trace log(N/O) versus [Fe/H] in the Milky Way and to compare this ratio with a set of chemical evolution models to understand the role of infall, outflow, and star formation e ciency in the building up of the Galactic disc. Methods. We used the abundances from IDR2-3, IDR4, IDR5 data releases of the Gaia-ESO Survey both for Galactic field and open cluster stars. We determined membership and average composition of open clusters and we separated thin and thick disc field stars. We considered the e ect of mixing in the abundance of N in giant stars. We computed a grid of chemical evolution models, suited to reproduce the main features of our Galaxy, exploring the e ects of the star formation e ciency, infall timescale, and di erential outflow. Results. With our samples, we map the metallicity range0:6 [Fe/H] 0.3 with a corresponding1:2 log(N/O) 0:2, where the secondary production of N dominates. Thanks to the wide range of Galactocentric distances covered by our samples, we can distinguish the behaviour of log(N/O) in di erent parts of the Galaxy. Conclusions. Our spatially resolved results allow us to distinguish di erences in the evolution of N/O with Galactocentric radius. Comparing the data with our models, we can characterise the radial regions of our Galaxy. A shorter infall timescale is needed in the inner regions, while the outer regions need a longer infall timescale, coupled with a higher star formation e ciency. We compare our results with nebular abundances obtained in MaNGA galaxies, finding in our Galaxy a much wider range of log(N/O) than in integrated observations of external galaxies of similar stellar mass, but similar to the ranges found in studies of individual H II regions.</p>},
  articleno    = {33224},
  author       = {Magrini, L. and Vincenzo, F. and Randich, S. and Pancino, E. and Casali, G. and Tautvaišien, G. and Drazdauskas, A. and Mikolaitis, S. and Minkevičiūt, R. and Stonkut, E. and Chorniy, Y. and Bagdonas, V. and Kordopatis, G. and Friel, E. and Roccatagliata, V. and Jiménez-Esteban, F. M. and Gilmore, G. and Vallenari, A. and Bensby, T. and Bragaglia, A. and Korn, A. J. and Lanzafame, A. C. and Smiljanic, R. and Bayo, A. and Casey, A. R. and Costado, M. T. and Franciosini, E. and Hourihane, A. and Jofré, P. and Lewis, J. and Monaco, L. and Morbidelli, L. and Sacco, G. and Worley, C.},
  issn         = {0004-6361},
  keyword      = {Galaxy: abundances,Galaxy: disk,Open clusters and associations: general},
  language     = {eng},
  month        = {10},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {The Gaia -ESO Survey : The N/O abundance ratio in the Milky Way?},
  url          = {http://dx.doi.org/10.1051/0004-6361/201833224},
  volume       = {618},
  year         = {2018},
}