HST Imaging of the Brightest z ∼ 8-9 Galaxies from UltraVISTA: The Extreme Bright End of the UV Luminosity Function - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue The Astrophysical Journal Année : 2017

HST Imaging of the Brightest z ∼ 8-9 Galaxies from UltraVISTA: The Extreme Bright End of the UV Luminosity Function

Mauro Stefanon
Ivo Labbé
  • Fonction : Auteur
Rychard J. Bouwens
  • Fonction : Auteur
Gabriel B. Brammer
  • Fonction : Auteur
Pascal Oesch
Marijn Franx
  • Fonction : Auteur
Johan P. U. Fynbo
  • Fonction : Auteur
Bo Milvang-Jensen
  • Fonction : Auteur
Adam Muzzin
  • Fonction : Auteur
Garth D. Illingworth
  • Fonction : Auteur
Karina I. Caputi
  • Fonction : Auteur
Benne W. Holwerda
  • Fonction : Auteur
Renske Smit
  • Fonction : Auteur
Dan Magee
  • Fonction : Auteur

Résumé

We report on the discovery of three especially bright candidate {z}{phot}≳ 8 galaxies. Five sources were targeted for follow-up with the Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3), selected from a larger sample of 16 bright (24.8≲ H≲ 25.5 mag) candidate z≳ 8 Lyman break galaxies (LBGs) identified over 1.6 degrees2 of the COSMOS/UltraVISTA field. These were selected as Y and J dropouts by leveraging the deep (Y-to-{K}{{S}}∼ 25.3{--}24.8 mag, 5σ ) NIR data from the UltraVISTA DR3 release, deep ground-based optical imaging from the CFHTLS and Suprime-Cam programs, and Spitzer/IRAC mosaics combining observations from the SMUVS and SPLASH programs. Through the refined spectral energy distributions, which now also include new HyperSuprimeCam g-, r-, i-, z-, and Y-band data, we confirm that 3/5 galaxies have robust {z}{phot}∼ 8.0{--}8.7, consistent with the initial selection. The remaining 2/5 galaxies have a nominal {z}{phot}∼ 2. However, with HST data alone, these objects have increased probability of being at z∼ 9. We measure mean UV continuum slopes β =-1.74+/- 0.35 for the three z∼ 8{--}9 galaxies, marginally bluer than similarly luminous z∼ 4{--}6 in CANDELS but consistent with previous measurements of similarly luminous galaxies at z∼ 7. The circularized effective radius for our brightest source is 0.9 ± 0.3 kpc, similar to previous measurements for a bright z∼ 11 galaxy and bright z∼ 7 galaxies. Finally, enlarging our sample to include the six brightest z∼ 8 LBGs identified over UltraVISTA (i.e., including three other sources from Labbé et al.) we estimate for the first time the volume density of galaxies at the extreme bright end ({M}{UV}∼ -22 mag) of the z∼ 8 UV luminosity function. Despite this exceptional result, the still large statistical uncertainties do not allow us to discriminate between a Schechter and a double-power-law form.

Dates et versions

insu-03666142 , version 1 (12-05-2022)

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Citer

Mauro Stefanon, Ivo Labbé, Rychard J. Bouwens, Gabriel B. Brammer, Pascal Oesch, et al.. HST Imaging of the Brightest z ∼ 8-9 Galaxies from UltraVISTA: The Extreme Bright End of the UV Luminosity Function. The Astrophysical Journal, 2017, 851, ⟨10.3847/1538-4357/aa9a40⟩. ⟨insu-03666142⟩
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