Gas Accretion and Star-Formation Rates with IFUs and Background Quasars

Nicolas F. Bouché (1)

1 IRAP - Institut de recherche en astrophysique et planétologie

Star forming galaxies (SFGs) are forming stars at a regular pace, forming the so-called main sequence (MS). However, all studies of their gas content show that their gas reservoir ought to be depleted in 0.5-2 Gyr. Thus, SFGs are thought to be fed by the continuous accretion of intergalactic gas in order to sustain their star-formation activity. However, direct observational evidence for this accretion phenomenon has been elusive. Theoretically, the accreted gas coming from the in-tergalactic medium is expected to orbit about the halo, delivering not just fuel for star-formation but also angular momentum to the galaxy. This accreting material is thus expected to form a gaseous structure that should be co-rotating with the host once at r < 0.3 R vir or r < 10 − 30 kpc. Because of the rough alignment between the star-forming disk and this extended gaseous structure, the accreting material can be most easily detected with the combination of background quasars and integral field units (IFUs). In this chapter, accretion studies using this technique are reviewed.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Nicolas F. Bouché. Gas Accretion and Star-Formation Rates with IFUs and Background Quasars. Gas accretion onto galaxies, Springer, pp.Pages 355-368, 2017, 978-3-319-52512-9. ⟨hal-02334920⟩