2009/06/12 by Saumyadip Samui, Raghunathan Srianand, R. Srianand +1
Engineering · Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #CCD and CMOS Imaging Sensors #Dark matter #Emission spectrum #Equivalent width #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Halo #Interstellar medium #Luminosity #Opacity #Physics #Redshift #Spectral line #Star formation #astro-ph.CO
paper · pdf · doi:10.1111/j.1365-2966.2009.15245.x
9 pages, 4 figures, 2 tables, Accepted for publication in MNRAS
arxiv created 2009/06/12 · openalex publication_date 2009/08/25 · arxiv updated 2015/05/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a semi-analytical model of star formation which explains simultaneously the observed ultraviolet (UV) luminosity function (LF) of high-redshift Lyman break galaxies (LBGs) and LFs of Lyman α emitters. We consider both models that use the Press–Schechter (PS) and Sheth–Tormen (ST) halo mass functions to calculate the abundances of dark matter haloes. The Lyman α LFs at z≲ 4 are well reproduced with only ≲10 per cent of the LBGs emitting Lyman α lines with rest equivalent width greater than the limiting equivalent width of the narrow band surveys. However, the observed LF at z > 5 can be reproduced only when we assume that nearly all LBGs are Lyman α emitters. Thus, it appears that 4 < z < 5 marks the epoch when a clear change occurs in the physical properties of the high-redshift galaxies. As Lyman α escape depends on dust and gas kinematics of the interstellar medium (ISM), this could mean that on an average the ISM at z > 5 could be less dusty, more clumpy and having more complex velocity field. All of these will enable easier escape of the Lyman α photons. At z > 5, the observed Lyman α LF are well reproduced with the evolution in the halo mass function along with very minor evolution in the physical properties of high-redshift galaxies. In particular, up to z= 6.5, we do not see the effect of evolving intergalactic medium opacity on the Lyman α escape from these galaxies.