SIMBAD references

We analyse the idea that the local dips (∼1 kpc along the Galactic radius) observed in oxygen abundance are associated with the infall of intergalactic low-abundant gas (∼0.2 Z_☉) on to the Galactic disc during the last ∼100 Myr. We term such infall events local streams. The derived masses of the falling gas (of the order of several times 10⁸ M_☉) are close to the observed ones (e.g. in the Magellanic Stream). Such local streams do not change the mean mass of oxygen ejected per core-collapse supernova (CC SN) event, so that our previous inference on probable upper initial masses for progenitors of CC SNe remains valid.