1998/02/28 by Ping He, Yuan‐Zhong Zhang, Yuan-Zhong Zhang · 6 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Context (archaeology) #Elliptical galaxy #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Geography #Lenticular galaxy #Luminosity #Luminous infrared galaxy #Peculiar galaxy #Physics #Redshift #Star formation #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/306697
published in The Astrophysical Journal 511(2), 574-584 (IOP Publishing) · 20pages (AASTeX), 10 eps figures, 4 tables, to appear in ApJ, 1999, Vol. 511
arxiv created 1998/10/16 · openalex publication_date 1999/02/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/08
The explanation for the existence of an excess population of faint blue galaxies (FBGs) has been a mystery for nearly two decades and remains one of the grand astronomical issues to date. Existing models cannot explain all of the observational data, such as galaxy number counts in the optical and infrared passbands and the redshift distributions of galaxies. Here, by modeling the morphological number counts derived from the Hubble Space Telescope , as well as the number counts in optical and infrared passbands and the redshift and color distributions of galaxies obtained from ground-based observations, we show that the "FBG problem" cannot be resolved if elliptical galaxies are assumed to have formed in an instantaneous burst of star formation at high redshift with no subsequent star formation events, which is the conventional scenario for formation and evolution of ellipticals. There exist great discrepancies between the observed B-K color distribution and the predicted distribution for ellipticals by such a pure luminosity evolution (PLE) model in the context of the conventional scenario. Neither can the mild evolution (i.e., the star formation events have lasted for a longer time than those of the instantaneous burst and passive evolution since the formation of galaxies) for ellipticals be accepted in the context of PLE assumption. The introduction of dust extinction also cannot save the PLE models. This conclusion holds for each of the three cosmological models under consideration: flat, open, and Λ-dominated. Hence, our investigation suggests that PLE assumption for elliptical galaxies is questionable, and number evolution may be essential for ellipticals.