2008MNRAS.384.1363F -
Mon. Not. R. Astron. Soc., 384, 1363-1376 (2008/March-2)
Mass-to-light ratio of Lyα emitters: implications of Lyα surveys at redshifts z = 5.7, 6.5, 7 and 8.8.
FERNANDEZ E.R. and KOMATSU E.
Abstract (from CDS):
Using a simple method to interpret the luminosity function of Lyα emitters, we explore properties of Lyα emitters from 5.7 ≤ z ≤ 8.8 with various assumptions about metallicity and stellar mass spectra. We constrain a mass-to-`observed light' ratio, Mh/Lband, where Mh refers to the total mass of the host halo and Lband refers to the observed luminosity of the source. For narrow-band surveys, Lband is simply related to the intrinsic Lyα luminosity with a survival fraction of Lyα photons, αesc. The mass-to-`bolometric light', Mh/Lbol, can also be deduced, once the metallicity and stellar mass spectrum are given. The inferred Mh/Lbol is more sensitive to metallicity than to the mass spectrum. We find the following constraints on a mass-to-light ratio of Lyα emitters from 5.7 ≤ z ≤ 7: (Mh/Lbol)(αescε1/γ)–1 = 21-38,14-26 and 9-17 for Z = 0, 1/50 and 1Z☉, respectively, where ε is the `duty cycle' of Lyα emitters and γ ∼ 2 is a local slope of the cumulative luminosity function, N(>L) ∝ L–γ, to which the current data are sensitive. Only weak lower limits are obtained for z = 8.8. Therefore, Lyα emitters are consistent with either starburst galaxies (Mh/Lbol∼ 0.1-1) with a smaller Lyα survival fraction, αescε1/γ ∼ 0.01-0.05, or normal populations (Mh/Lbol∼ 10) if a good fraction of Lyα photons survived, αescε1/γ ∼ 0.5-1. We find no evidence for the end of reionization in the luminosity functions of Lyα emitters discovered in the current Lyα surveys, including recent discovery of one Lyα emitter at z = 7. The data are consistent with no evolution of intrinsic properties of Lyα emitters or neutral fraction in the intergalactic medium up to z = 7. No detection of sources at z = 8.8 does not yield a significant constraint yet. We also show that the lack of detection at z = 8.8 does not rule out the high-z galaxies being the origin of the excess near-infrared background.
Abstract Copyright:
2008 The Authors. Journal compilation © 2008 RAS
Journal keyword(s):
galaxies: high-redshift - cosmology: observations - cosmology: theory - early Universe - infrared: galaxies
Simbad objects:
5
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