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http://hdl.handle.net/20.500.12386/26198
Title: | Constraining the Warm Dark Matter Particle Mass through Ultra-deep UV Luminosity Functions at z=2 | Authors: | MENCI, Nicola Sanchez, N. G. CASTELLANO, MARCO GRAZIAN, Andrea |
Issue Date: | 2016 | Journal: | THE ASTROPHYSICAL JOURNAL | Number: | 818 | Issue: | 1 | First Page: | 90 | Abstract: | We compute the mass function of galactic dark matter halos for different values of the warm dark matter (WDM) particle mass m<SUB>X</SUB> and compare it with the number density of ultra-faint galaxies derived from the deepest UV luminosity function available so far at redshift z ≈ 2. The magnitude limit M<SUB>UV</SUB> = -13 reached by such observations allows us to probe the WDM mass functions down to scales close to or smaller than the half-mass mode mass scale ∼10<SUP>9</SUP> M<SUB>☉</SUB>. This allowed for an efficient discrimination among predictions for different m<SUB>X</SUB> which turn out to be in practice independent of the star formation efficiency η adopted to associate the observed UV luminosities of galaxies to the corresponding dark matter halo masses. Adopting a conservative approach to take into account the existing theoretical uncertainties in the galaxy halo mass function, we obtain a robust limit m<SUB>X</SUB> ≥ 1.8 keV for the mass of thermal relic WDM particles when comparing with the measured abundance of the faintest galaxies, while m<SUB>X</SUB> ≥ 1.5 keV is obtained when we compare with the Schechter fit to the observed luminosity function. The corresponding lower limit for sterile neutrinos depends on the modeling of the production mechanism; for instance m<SUB>sterile</SUB> ≳ 4 keV holds for the Shi-Fuller mechanism. We discuss the impact of observational uncertainties on the above bound on m<SUB>X</SUB>. In the cold dark matter (CDM) limit {m}<SUB>X</SUB>\gg 1 {{keV}} we recover the generic CDM result that very inefficient star formation efficiency is required to match the observed galaxy abundances. As a baseline for comparison with forthcoming observational results from the Hubble Space Telescope Frontier Field project, we provide predictions for the number density of faint galaxies with M<SUB>UV</SUB> = -13 for different values of the WDM particle mass and of the star formation efficiency η, which are valid up to z ≈ 4. | URI: | http://hdl.handle.net/20.500.12386/26198 | URL: | https://iopscience.iop.org/article/10.3847/0004-637X/818/1/90 | ISSN: | 0004-637X | DOI: | 10.3847/0004-637X/818/1/90 | Bibcode ADS: | 2016ApJ...818...90M | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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Menci_2016_ApJ_818_90.pdf | Pdf editoriale | 349.25 kB | Adobe PDF | View/Open |
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