UV-CONTINUUM SLOPES OF >4000 z ∼ 4–8 GALAXIES FROM THE HUDF/XDF, HUDF09, ERS, CANDELS-SOUTH, AND CANDELS-NORTH FIELDS

By R. Bouwens, G. Illingworth, P. Oesch, I. Labbé, P. V. van Dokkum, M. Trenti, M. Franx, R. Smit, V. González, D. Magee. 2013

249 citations recorded by the source corpus.

We measure the UV-continuum slope β for over 4000 high-redshift galaxies over a wide range of redshifts z ∼ 4–8 and luminosities from the HST HUDF/XDF, HUDF09-1, HUDF09-2, ERS, CANDELS-N, and CANDELS-S data sets. Our new β results reach very faint levels at z ∼ 4 (−15.5 mag: ), z ∼ 5 (−16.5 mag: ), and z ∼ 6 and z ∼ 7 (−17 mag: ). Inconsistencies between previous studies led us to conduct a comprehensive review of systematic errors and develop a new technique for measuring β that is robust against biases that arise from the impact of noise. We demonstrate, by object-by-object comparisons, that all previous studies, including our own and those done on the latest HUDF12 data set, suffered from small systematic errors in β. We find that after correcting for the systematic errors (typically Δβ ∼ 0.1–0.2) all β results at z ∼ 7 from different groups are in excellent agreement. The mean β we measure for faint (−18 mag: ) z ∼ 4, z ∼ 5, z ∼ 6, and z ∼ 7 galaxies is −2.03 ± 0.03 ± 0.06 (random and systematic errors), −2.14 ± 0.06 ± 0.06, −2.24 ± 0.11 ± 0.08, and −2.30 ± 0.18 ± 0.13, respectively. Our new β values are redder than we have reported in the past, but bluer than other recent results. Our previously reported trend of bluer β's at lower luminosities is confirmed, as is the evolution to bluer β's at high redshifts. β appears to show only a mild luminosity dependence faintward of MUV, AB ∼ −19 mag, suggesting that the mean β asymptotes to ∼−2.2 to −2.4 for faint z ⩾ 4 galaxies. At z ∼ 7, the observed β's suggest non-zero, but low dust extinction, and they agree well with values predicted in cosmological hydrodynamical simulations.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/79c76a6b42311d0f565ce99ad688a7ddb6ac79d6

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. L. Hernquist
2. P. Hopkins
3. Richard S. Ellis
4. R. Somerville
5. C. Conroy
6. R. Dav'e
7. P. V. van Dokkum
8. M. Franx

In Electrical and Electronic Engineering

1. R. Bouwens
2. P. Oesch
3. J. Dunlop
4. G. Illingworth
5. D. Stark
6. I. Labbé
7. M. Ouchi
8. R. McLure

In Instrumentation

1. C. Conroy
2. Richard S. Ellis
3. P. V. van Dokkum
4. M. Franx
5. Christopher J. Conselice
6. R. Somerville
7. R. Bouwens
8. R. Dav'e

Citations in the corpus

• The Universe Is Reionizing at z ∼ 7: Bayesian Inference of the IGM Neutral Fraction Using Lyα Emission from Galaxies (2017, background): “…of LBGs emitting Lyα increases with redshift (Stark et al. 2010; Curtis-Lake et al. 2012; Hayes et al. 2011; Cassata et al. 2015), likely because the dust fraction in galaxies decreases (e.g., Finkelstein et al. 2012b; Bouwens et al. 2014) which reduces the absorption of Lyα (Hayes et al. 2011).”
• THE EVOLUTION OF THE GALAXY REST-FRAME ULTRAVIOLET LUMINOSITY FUNCTION OVER THE FIRST TWO BILLION YEARS (2014, methodology): “As a bevy of recent work has shown, this dust correction is important even out to z ~ 7–8 (e.g., Finkelstein et al. 2012b; Dunlop et al. 2013; Bouwens et al. 2014, see also Section 7).”
• The Dearth of z ∼ 10 Galaxies in All HST Legacy Fields—The Rapid Evolution of the Galaxy Population in the First 500 Myr (2017, background): “In marked contrast to this, the brightest currently known z ∼ 8 − 10 galaxy candidates show significantly bluer slopes of β = −2.1±0.3 based on the combination of HST+Spitzer photometry (Wilkins et al. 2016, see also Oesch et al. 2014, Bouwens et al. 2014).”
• THE EVOLUTION OF THE GALAXY STELLAR MASS FUNCTION AT z = 4–8: A STEEPENING LOW-MASS-END SLOPE WITH INCREASING REDSHIFT (2015, background): “…2011; Oesch et al. 2012; Schenker et al. 2013b; Lorenzoni et al. 2013; Finkelstein et al. 2015; Bouwens et al. 2015), the rest-frame UV spectral slope (e.g., Finkelstein et al. 2012; Bouwens et al. 2014), and the cosmic star formation rate density (SFRD; see Madau & Dickinson 2014 for a review).”
• Stellar population effects on the inferred photon density at reionization (2015, background): “By contrast Bouwens et al. (2014) claim stronger evolution with both luminosity and age, with ∆β ∼ 0.7 over the same luminosity range at z = 4.”
• Identification of the brightest Lyα emitters at z = 6.6 : Implications for the evolution of the luminosity function in the reionization era (2015, methodology): “Galaxies selected this way are called Lyman-Break Galaxies (LBGs) and the current largest sample contains already 10,000s (e.g. Bouwens et al. 2014b).”
• MORPHOLOGIES OF ∼190,000 GALAXIES AT z = 0–10 REVEALED WITH HST LEGACY DATA. I. SIZE EVOLUTION (2015, result): “These LBGs are selected with the color criteria, similar to those of Bouwens et al. (2014b).”
• UVUDF: ULTRAVIOLET THROUGH NEAR-INFRARED CATALOG AND PHOTOMETRIC REDSHIFTS OF GALAXIES IN THE HUBBLE ULTRA DEEP FIELD (2015, background): “…Ryan et al. 2007; Cameron & Driver 2009; Bouwens et al. 2011b; Dunlop et al. 2013; Schenker et al. 2013; McLure et al. 2013; Oesch et al. 2013; Bouwens et al. 2014), to observe the evolution in the star formation rate density (e.g., Bouwens et al. 2007, 2009, 2010), to determine the…”
• The Frontier Fields lens modelling comparison project (2016, background): “…high-redshift sources down to faint luminosities, thus helping inventory and identify galaxies that might have re-ionized the universe (Vanzella et al. 2012, 2014; Bouwens et al. 2014; Robertson et al. 2015; Bouwens et al. 2015; Vanzella et al. 2015, 2016; Huang et al. 2016; Livermore et al. 2016).”
• Dust Attenuation Curves in the Local Universe: Demographics and New Laws for Star-forming Galaxies and High-redshift Analogs (2018, background): “This is often the case for high redshift galaxies (e.g.,Bouwens et al. 2014; Smit et al. 2014; Bowler et al. 2015; Finkelstein et al. 2015; Oesch et al. 2014), and will be common for earlyuniverse galaxy populations to be studied by JWST (unless accompanied by observations made by ALMA).”
• ALMA SPECTROSCOPIC SURVEY IN THE HUBBLE ULTRA DEEP FIELD: THE INFRARED EXCESS OF UV-SELECTED z = 2–10 GALAXIES AS A FUNCTION OF UV-CONTINUUM SLOPE AND STELLAR MASS (2016, methodology): “The β value we utilize here is motivated by the results of Bouwens et al. (2012), Finkelstein et al. (2012), Bouwens et al. (2014), Kurczynski et al. (2014), and Wilkins et al. (2016a) who find evidence for bluer slopes for higher redshift and generally fainter, lower-mass galaxies. prescriptions…”
• The mass evolution of the first galaxies: stellar mass functions and star formation rates at 4 < z < 7 in the CANDELS GOODS-South field (2014, background): “To this end, more recent analyses (Bouwens et al. 2013; Rogers et al. 2014) which increase sample sizes and minimize biases in the sample selection and β measurements are in good agreement, with both studies finding a clear luminosity dependence.”
• The galaxy luminosity function at z ≃ 6 and evidence for rapid evolution in the bright end from z ≃ 7 to 5 (2014, methodology): “Although the Finkelstein et al. (2014) analysis used a sub-set of the larger area of imaging used by Bouwens et al. (2014), the results are in good agreement with the ground-based analysis presented here, and could indicate large over-densities in the additional fields incorporated by Bouwens et…”
• Constraining the galaxy–halo connection over the last 13.3 Gyr: star formation histories, galaxy mergers and structural properties (2017, methodology): “We use the following relationship independent of redshift: 〈β〉 = −0.11 × (MUV + 19.5) − 2, which is consistent with previous determination of the β slope (see e.g., Bouwens et al. 2014).”