THE BRIGHTEST OF REIONIZING GALAXIES SURVEY: CONSTRAINTS ON THE BRIGHT END OF THE z ∼ 8 LUMINOSITY FUNCTION

By L. Bradley, M. Trenti, P. Oesch, M. Stiavelli, T. Treu, R. Bouwens, J. Michael Shull, B. Holwerda, N. Pirzkal. 2012

133 citations recorded by the source corpus.

We report the discovery of 33 Lyman-break galaxy candidates at z ∼ 8 detected in Hubble Space Telescope Wide Field Camera 3 (WFC3) imaging as part of the Brightest of Reionizing Galaxies (BoRG) pure-parallel survey. The ongoing BoRG survey currently has the largest area (274 arcmin2) with Y098 (or Y105), J125, and H160 band coverage needed to search for z ∼ 8 galaxies, about three times the current CANDELS area, and slightly larger than what will be the final CANDELS wide component with Y105 data (required to select z ∼ 8 sources). Our sample of 33 relatively bright Y098-dropout galaxies have J125-band magnitudes between 25.5 and 27.4 mag. This is the largest sample of bright (J125 ≲ 27.4) z ∼ 8 galaxy candidates presented to date. Combining our data set with the Hubble Ultra-Deep Field data set, we constrain the rest-frame ultraviolet galaxy luminosity function at z ∼ 8 over the widest dynamic range currently available. The combined data sets are well fitted by a Schechter function, i.e., , without evidence for an excess of sources at the bright end. At 68% confidence, for h = 0.7 we derive ϕ* = (4.3+3.5−2.1) × 10−4 Mpc−3, M* = −20.26+0.29−0.34, and a very steep faint-end slope α = −1.98+0.23−0.22. While the best-fit parameters still have a strong degeneracy, especially between ϕ* and M*, our improved coverage at the bright end has reduced the uncertainty of the faint-end power-law slope at z ∼ 8 compared to the best previous determination at ±0.4. With a future expansion of the BoRG survey, combined with planned ultradeep WFC3/IR observations, it will be possible to further reduce this uncertainty and clearly demonstrate the steepening of the faint-end slope compared to measurements at lower redshift, thereby confirming the key role played by small galaxies in the reionization of the universe.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/54da5bf567d2bcad438256cbf7c39a5a642b2467

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In Astronomy and Astrophysics

1. Richard S. Ellis
2. R. Bouwens
3. P. V. van Dokkum
4. P. Oesch
5. J. Dunlop
6. L. Hernquist
7. M. Franx
8. P. Hopkins

In Instrumentation

1. Richard S. Ellis
2. P. V. van Dokkum
3. R. Bouwens
4. M. Franx
5. J. Dunlop
6. P. Oesch
7. G. Illingworth
8. I. Labbé

Citations in the corpus

• ON THE LACK OF EVOLUTION IN GALAXY STAR FORMATION EFFICIENCY (2012, methodology): “At high redshifts, we include recent measurements of stellar masses and star formation rates to z = 8 (Bouwens et al. 2012, 2011; McLure et al. 2011; Bradley et al. 2012).”
• A new multifield determination of the galaxy luminosity function at z = 7-9 incorporating the 2012 Hubble Ultra-Deep Field imaging (2012, methodology): “Based on these 41 fields (total area 180 arcmin2) an initial candidate list was constructed using the colour-cuts employed by Bradley et al. (2012), but based on our own photometry and depth analysis (see below).”
• EVIDENCE FOR UBIQUITOUS HIGH-EQUIVALENT-WIDTH NEBULAR EMISSION IN z ∼ 7 GALAXIES: TOWARD A CLEAN MEASUREMENT OF THE SPECIFIC STAR-FORMATION RATE USING A SAMPLE OF BRIGHT, MAGNIFIED GALAXIES (2013, methodology): “One of the sources in our z ∼ 7 sample was previously reported by Bradley et al. (2012a) based on a study of Abell 1703.”
• A CENSUS OF STAR-FORMING GALAXIES IN THE Z ∼ 9–10 UNIVERSE BASED ON HST+SPITZER OBSERVATIONS OVER 19 CLASH CLUSTERS: THREE CANDIDATE Z ∼ 9–10 GALAXIES AND IMPROVED CONSTRAINTS ON THE STAR FORMATION RATE DENSITY AT Z ∼ 9.2 (2012, methodology): “…is (1) to leverage existing welldetermined LFs that already exist at z ∼ 7-8 from blank field studies (e.g., Bouwens et al. 2011b; Oesch et al. 2012b; Bradley et al. 2012) not subject to potentially large selection volume uncertainties and (2) then to use our searches for z ∼ 7-10 galaxies behind…”
• THE 2012 HUBBLE ULTRA DEEP FIELD (UDF12): OBSERVATIONAL OVERVIEW (2012, background): “…2012, Ono et al. 2010, Bunker et al. 2010, Finkelstein et al. 2010, 2012b,a, Yan et al. 2011b,a, McLure et al. 2010, 2011, Grazian et al. 2011, 2012, Bradley et al. 2012, Dunlop et al. 2012a,b), particularly concerning the extent to which these galaxies may or may not be able to account for…”
• THE MOST LUMINOUS z ∼ 9–10 GALAXY CANDIDATES YET FOUND: THE LUMINOSITY FUNCTION, COSMIC STAR-FORMATION RATE, AND THE FIRST MASS DENSITY ESTIMATE AT 500 Myr (2013, background): “Over the last few years, several z ∼ 8 UV LF determinations have been published by several teams based on WFC3/IR data sets (e.g., Bouwens et al. 2010b, 2011b; Yan et al. 2011; Bradley et al. 2012; Oesch et al. 2012b; Lorenzoni et al. 2013; Schenker et al. 2013; McLure et al. 2013).”
• The COSMOS2015 galaxy stellar mass function . Thirteen billion years of stellar mass assembly in ten snapshots (2017, background): “Behroozi et al. used a larger set of SMFs, but at z > 4 these are all derived from LBG samples (Stark et al. 2009; Lee et al. 2012; Bouwens et al. 2011; Bradley et al. 2012), possibly biased at high masses as we discussed in Sect.”
• The Frontier Fields: Survey Design and Initial Results (2016, methodology): “Thanks toWFC3, detections of z ∼ 8 candidates are now relatively commonplace (e.g. Labbe et al. 2010; Finkelstein et al. 2010; Yan et al. 2011; McClure et al. 2011, Bradley et al. 2012).”
• THE UV LUMINOSITY FUNCTION OF STAR-FORMING GALAXIES VIA DROPOUT SELECTION AT REDSHIFTS z ∼ 7 AND 8 FROM THE 2012 ULTRA DEEP FIELD CAMPAIGN (2012, methodology): “As pointed out in Robertson (2010b), Bouwens et al. (2011), and Bradley et al. (2012), there remains a large degeneracy between M∗UV and the faint end slope, α without sufficient data at the bright end.”
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report (2015, background): “Finding candidate z > 7 galaxies has been pursued in two ways - from moderate area but very deep imaging surveys (e.g., UDF, Subaru Deep Field, CANDELS) and from images of strongly lensing clusters of galaxies (e.g., Bradley et al. 2008, Postman et al. 2012).”
• THE ABUNDANCE OF STAR-FORMING GALAXIES IN THE REDSHIFT RANGE 8.5–12: NEW RESULTS FROM THE 2012 HUBBLE ULTRA DEEP FIELD CAMPAIGN (2012, methodology): “This calculation is performed assuming simple luminosity evolution from z ∼ 8, keeping the luminosity function normalization φ⋆ and faint-end slope α fixed at the z ∼ 8 values measured by Bradley et al. (2012).”
• A SPECTROSCOPIC REDSHIFT MEASUREMENT FOR A LUMINOUS LYMAN BREAK GALAXY AT z = 7.730 USING KECK/MOSFIRE (2015, background): “Interestingly, this source is ∼ 0.5 mag brighter than any source identified in the wide-area BoRG and HIPPIES surveys (e.g. Trenti et al. 2011; Yan et al. 2011; Bradley et al. 2012; Schmidt et al. 2014).”
• THE STAR FORMATION HISTORIES OF LOCAL GROUP DWARF GALAXIES. I. HUBBLE SPACE TELESCOPE/WIDE FIELD PLANETARY CAMERA 2 OBSERVATIONS (2014, methodology): “They employ a novel probabilistic model that incorporates a wide range of data from high redshift SFRs (e.g., Bouwens et al. 2011, 2012; Bradley et al. 2012) to observations of recent star formation in the local universe (e.g., 21 Hα, UV, 24 µm; Salim et al. 2007; Kennicutt et al. 2008; Moustakas…”
• CLASH: THREE STRONGLY LENSED IMAGES OF A CANDIDATE z ≈ 11 GALAXY (2012, methodology): “Based on the combined HST data from the HUDF09, ERS, CANDELS, and BoRG pure parallel fields, Bradley et al. (2012b) find the z ∼ 8 LF follows a Schechter (1976) function with a normalization φ∗ = 4.3+3.5−2.1×10−4 Mpc−3, characteristic rest-frame UV absolute magnitude M∗UV = −20.26 +0.29 −0.34, and…”
• The UV continua and inferred stellar populations of galaxies at z ~7-9 revealed by the Hubble Ultra-Deep Field 2012 campaign (2012, methodology): “…Society at U niversity of St A ndrew s on A ugust 13, 2014 http://m nras.oxfordjournals.org/ D Stellar populations at z 7−9 from HUDF12 3521 Koekemoer et al. 2011; Grazian et al. 2012; Oesch et al. 2012), and through parallel imaging programmes such as the BoRG survey (e.g. Bradley et al. 2012).”
• Full-data Results of Hubble Frontier Fields: UV Luminosity Functions at z ∼ 6–10 and a Consistent Picture of Cosmic Reionization (2017, methodology): “We use recent results of blank field surveys; Bouwens et al. (2015); Bowler et al. (2014); Ouchi et al. (2009); Bradley et al. (2012); Oesch et al. (2013); Calvi et al. (2016).”
• PROBING THE DAWN OF GALAXIES AT z ∼ 9–12: NEW CONSTRAINTS FROM HUDF12/XDF AND CANDELS DATA (2013, background): “Since the z ∼ 8 density is well-established from the field (e.g. Oesch et al. 2012b; Bradley et al. 2012), this gave a more robust measure than trying to infer source densities directly using lensing models.”
• THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). I. SURVEY OVERVIEW AND FIRST DATA RELEASE (2015, result): “This model is in excellent agreement with the actual number of LBGs detected in blank fields (e.g., Bradley et al. 2012; Oesch et al. 2013; Bouwens et al. 2014; Schmidt et al. 2014b).”