We exploit a sample of ultra-faint high-redshift galaxies (demagnified Hubble Space Telescope, HST, H 160 magnitude > 30) in the Frontier Fields clusters A2744 and M0416 to constrain a theoretical model for the UV luminosity function in the presence of photoionization feedback. The objects have been selected on the basis of accurate photometric redshifts computed from multi-band photometry including seven HST bands and deep K s and IRAC observations. Magnification is computed on an object-by-object basis from all available lensing models of the two clusters. We take into account source detection completeness as a function of luminosity and size, magnification effects, and systematics in the lens modeling of the clusters under investigation. We find that our sample of high-z galaxies constrain the cutoff halo circular velocity below which star formation is suppressed by photoionization feedback to km s-1. This circular velocity corresponds to a halo mass of ≈5.6 × 109Mo and ≈2.3 × 109 M o at z = 5 and 10, respectively: higher-mass halos can thus sustain continuous star formation activity without being quenched by external ionizing flux. More stringent constraints are prevented by the uncertainty in the modeling of the cluster lens, as embodied by systematic differences among the lens models available.

We exploit a sample of ultra-faint high-redshift galaxies (demagnified Hubble Space Telescope, HST, H160 magnitude > 30) in the Frontier Fields clusters A2744 and M0416 to constrain a theoretical model for the UV luminosity function in the presence of photoionization feedback. The objects have been selected on the basis of accurate photometric redshifts computed from multi-band photometry including seven HST bands and deep Ks and IRAC observations. Magnification is computed on an object-by-object basis from all available lensing models of the two clusters. We take into account source detection completeness as a function of luminosity and size, magnification effects, and systematics in the lens modeling of the clusters under investigation. We find that our sample of high-z galaxies constrain the cutoff halo circular velocity below which star formation is suppressed by photoionization feedback to ${v}_{c}^{{ m{cut}}}lt 50$ km s−1. This circular velocity corresponds to a halo mass of ≈5.6 × 109 M⊙ and ≈2.3 × 109 M⊙ at z = 5 and 10, respectively: higher-mass halos can thus sustain continuous star formation activity without being quenched by external ionizing flux. More stringent constraints are prevented by the uncertainty in the modeling of the cluster lens, as embodied by systematic differences among the lens models available.

Constraints on Photoionization Feedback from Number Counts of Ultra-faint High-redshift Galaxies in the Frontier Fields

FERRARA, ANDREA;
2016

Abstract

We exploit a sample of ultra-faint high-redshift galaxies (demagnified Hubble Space Telescope, HST, H160 magnitude > 30) in the Frontier Fields clusters A2744 and M0416 to constrain a theoretical model for the UV luminosity function in the presence of photoionization feedback. The objects have been selected on the basis of accurate photometric redshifts computed from multi-band photometry including seven HST bands and deep Ks and IRAC observations. Magnification is computed on an object-by-object basis from all available lensing models of the two clusters. We take into account source detection completeness as a function of luminosity and size, magnification effects, and systematics in the lens modeling of the clusters under investigation. We find that our sample of high-z galaxies constrain the cutoff halo circular velocity below which star formation is suppressed by photoionization feedback to ${v}_{c}^{{ m{cut}}}lt 50$ km s−1. This circular velocity corresponds to a halo mass of ≈5.6 × 109 M⊙ and ≈2.3 × 109 M⊙ at z = 5 and 10, respectively: higher-mass halos can thus sustain continuous star formation activity without being quenched by external ionizing flux. More stringent constraints are prevented by the uncertainty in the modeling of the cluster lens, as embodied by systematic differences among the lens models available.
Settore FIS/05 - Astronomia e Astrofisica
dark ages, reionization, first stars, galaxies: high-redshift
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11384/64706
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