Matches in SemOpenAlex for { <https://semopenalex.org/work/W3014507441> ?p ?o ?g. }
- W3014507441 endingPage "2575" @default.
- W3014507441 startingPage "2561" @default.
- W3014507441 abstract "We investigate the age-chemical abundance structure of the outer Galactic disc at a galactocentric distance of r > 10 kpc as recently revealed by the SDSS/APOGEE survey. Two sequences are present in the [alpha/Fe]-[Fe/H] plane with systematically different stellar ages. Surprisingly, the young sequence is less metal-rich, suggesting a recent dilution process by additional gas accretion. As the stars with the lowest iron abundance in the younger sequence also show an enhancement in alpha-element abundance, the gas accretion event must have involved a burst of star formation. In order to explain these observations, we construct a chemical evolution model. In this model we include a relatively short episode of gas accretion at late times on top of an underlying secular accretion over long timescales. Our model is successful at reproducing the observed distribution of stars in the three dimensional space of [alpha/Fe]-[Fe/H]-Age in the outer disc. We find that a late-time accretion with a delay of 8.2 Gyr and a timescale of 0.7 Gyr best fits the observed data, in particular the presence of the young, metal-poor sequence. Our best-fit model further implies that the amount of accreted gas in the late-time accretion event needs to be about three times the local gas reservoir in the outer disc at the time of accretion in order to sufficiently dilute the metal abundance. Given this large fraction, we interpret the late-time accretion event as a minor merger presumably with a gas-rich dwarf galaxy with a mass M_* < 10^9 M_Sun and a gas fraction of ~ 75 per cent." @default.
- W3014507441 created "2020-04-10" @default.
- W3014507441 creator A5007295322 @default.
- W3014507441 creator A5022988172 @default.
- W3014507441 creator A5024690331 @default.
- W3014507441 creator A5033109695 @default.
- W3014507441 creator A5035586913 @default.
- W3014507441 creator A5050902912 @default.
- W3014507441 creator A5063308901 @default.
- W3014507441 creator A5074802467 @default.
- W3014507441 creator A5087189932 @default.
- W3014507441 date "2020-04-04" @default.
- W3014507441 modified "2023-10-16" @default.
- W3014507441 title "The age–chemical abundance structure of the Galaxy I: evidence for a late-accretion event in the outer disc at z ∼ 0.6" @default.
- W3014507441 cites W1582881973 @default.
- W3014507441 cites W1656523990 @default.
- W3014507441 cites W1836177459 @default.
- W3014507441 cites W1841138391 @default.
- W3014507441 cites W1864516950 @default.
- W3014507441 cites W1921289443 @default.
- W3014507441 cites W1943306457 @default.
- W3014507441 cites W1963642624 @default.
- W3014507441 cites W1969174337 @default.
- W3014507441 cites W1971056876 @default.
- W3014507441 cites W1975777137 @default.
- W3014507441 cites W1980935497 @default.
- W3014507441 cites W1986460898 @default.
- W3014507441 cites W1994166266 @default.
- W3014507441 cites W2000054184 @default.
- W3014507441 cites W2029263067 @default.
- W3014507441 cites W2063568047 @default.
- W3014507441 cites W2066453499 @default.
- W3014507441 cites W2068967919 @default.
- W3014507441 cites W2070508637 @default.
- W3014507441 cites W2074094455 @default.
- W3014507441 cites W2082831408 @default.
- W3014507441 cites W2089947188 @default.
- W3014507441 cites W2094702580 @default.
- W3014507441 cites W2095358030 @default.
- W3014507441 cites W2100833883 @default.
- W3014507441 cites W2107745783 @default.
- W3014507441 cites W2108378229 @default.
- W3014507441 cites W2125161872 @default.
- W3014507441 cites W2125174497 @default.
- W3014507441 cites W2129760210 @default.
- W3014507441 cites W2140137154 @default.
- W3014507441 cites W2140888726 @default.
- W3014507441 cites W2152216557 @default.
- W3014507441 cites W2152356810 @default.
- W3014507441 cites W2155010863 @default.
- W3014507441 cites W2155593555 @default.
- W3014507441 cites W2169344843 @default.
- W3014507441 cites W2216753448 @default.
- W3014507441 cites W2469810790 @default.
- W3014507441 cites W2514709668 @default.
- W3014507441 cites W2528641579 @default.
- W3014507441 cites W2593224863 @default.
- W3014507441 cites W2740236269 @default.
- W3014507441 cites W2740853133 @default.
- W3014507441 cites W2766249080 @default.
- W3014507441 cites W2781275565 @default.
- W3014507441 cites W2783976032 @default.
- W3014507441 cites W2788110959 @default.
- W3014507441 cites W2789204937 @default.
- W3014507441 cites W2791740655 @default.
- W3014507441 cites W2798717076 @default.
- W3014507441 cites W2884902244 @default.
- W3014507441 cites W2890693341 @default.
- W3014507441 cites W2901112184 @default.
- W3014507441 cites W2908112692 @default.
- W3014507441 cites W2912891060 @default.
- W3014507441 cites W2920120417 @default.
- W3014507441 cites W2949380767 @default.
- W3014507441 cites W2952751471 @default.
- W3014507441 cites W2962807893 @default.
- W3014507441 cites W2972523882 @default.
- W3014507441 cites W2977865177 @default.
- W3014507441 cites W3098197335 @default.
- W3014507441 cites W3099718057 @default.
- W3014507441 cites W3099975694 @default.
- W3014507441 cites W3100002128 @default.
- W3014507441 cites W3100174716 @default.
- W3014507441 cites W3100392305 @default.
- W3014507441 cites W3100528003 @default.
- W3014507441 cites W3101463779 @default.
- W3014507441 cites W3101683237 @default.
- W3014507441 cites W3102363873 @default.
- W3014507441 cites W3102909867 @default.
- W3014507441 cites W3102910756 @default.
- W3014507441 cites W3103246553 @default.
- W3014507441 cites W3103709099 @default.
- W3014507441 cites W3103868583 @default.
- W3014507441 cites W3105904302 @default.
- W3014507441 cites W3106167992 @default.
- W3014507441 cites W3106294757 @default.
- W3014507441 cites W3106445279 @default.
- W3014507441 cites W3106525718 @default.
- W3014507441 cites W3123753455 @default.