2009/02/28 by Mark Dijkstra, Abraham Loeb
Physics and Astronomy · #Accretion (finance) #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Cold dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Gravitation #Gravitational potential #Physics #Quasar #Redshift #astro-ph.CO
paper · pdf · doi:10.1111/j.1365-2966.2009.15533.x
MNRAS in press. 13 pages, 6 figures. Discussion + references added. Main conclusions unaffected
arxiv created 2009/10/15 · openalex publication_date 2009/11/02 · arxiv updated 2015/05/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Recent hydrodynamic simulations of galaxy formation reveal streams of cold (T∼ 104 K) gas flowing into the centres of dark matter haloes as massive as 1012−13.5 M⊙ at redshifts z∼ 1–3. In this paper, we show that if ≳20 per cent of the gravitational binding energy of the gas is radiated away then the simulated cold flows are spatially extended Lyα sources with luminosities, Lyα linewidths and number densities that are comparable to those of observed Lyα blobs. Furthermore, the filamentary structure of the cold flows can explain the wide range of observed Lyα blob morphologies. Since the most massive haloes form in dense environments, the association of Lyα blobs with overdense regions arise naturally. We argue that Lyα blobs – even those which are clearly associated with starburst galaxies or quasars – provide direct observational support for the cold accretion mode of galaxies. We discuss various testable predictions of this association.