The colour distribution of galaxies at redshift five

Abstract

We present the results of a study investigating the rest-frame ultra-violet (UV) spectral slopes of redshift z~5 Lyman-break galaxies (LBGs). By combining deep Hubble Space Telescope imaging of the CANDELS and HUDF fields with ground-based imaging from the UKIDSS Ultra Deep Survey (UDS), we have produced a large sample of z~5 LBGs spanning an unprecedented factor of >100 in UV luminosity. Based on this sample we find a clear colour-magnitude relation (CMR) at z~5, such that the rest-frame UV slopes (beta) of brighter galaxies are notably redder than their fainter counterparts. We determine that the z~5 CMR is well described by a linear relationship of the form: d beta = (-0.12 +/- 0.02) d Muv, with no clear evidence for a change in CMR slope at faint magnitudes (i.e. Muv > -18.9). Using the results of detailed simulations we are able, for the first time, to infer the intrinsic (i.e. free from noise) variation of galaxy colours around the CMR at z~5. We find significant (12 sigma) evidence for intrinsic colour variation in the sample as a whole. Our results also demonstrate that the width of the intrinsic UV slope distribution of z~5 galaxies increases from Delta(beta)=0.1 at Muv=-18 to Delta(beta)=0.4 at Muv=-21. We suggest that the increasing width of the intrinsic galaxy colour distribution and the CMR itself are both plausibly explained by a luminosity independent lower limit of beta=-2.1, combined with an increase in the fraction of red galaxies in brighter UV-luminosity bins.

13 pages, 8 colour figures. Updated in response to referee report; accepted in MNRAS

References in corpus (43)

• Astropy: A Community Python Package for Astronomy
• Stellar population synthesis at the resolution of 2003
• Galactic Stellar and Substellar Initial Mass Function
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Starburst99: Synthesis Models for Galaxies with Active Star Formation
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey
• CANDELS: The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey - The Hubble Space Telescope Observations, Imaging Data Products and Mosaics
• Accurate photometric redshifts for the CFHT Legacy Survey calibrated using the VIMOS VLT Deep Survey
• Lyman Break Galaxies at z>4 and the Evolution of the UV Luminosity Density at High Redshift
• Rest-Frame Ultraviolet Spectra of z~3 Lyman Break Galaxies
• Dust Absorption And The Ultraviolet Luminosity Density At z \approx 3 As Calibrated By Local Starburst Galaxies
• Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North
• The Hubble Ultra Deep Field
• The Abundance of Star-Forming Galaxies in the Redshift Range 8.5 to 12: New Results from the 2012 Hubble Ultra Deep Field Campaign
• UV-continuum slopes at z~4-7 from the HUDF09+ERS+CANDELS observations: Discovery of a well-defined UV-color magnitude relationship for z>=4 star-forming galaxies
• The Galaxy Mass Function up to z=4 in the GOODS-MUSIC sample: into the epoch of formation of massive galaxies
• A new multi-field determination of the galaxy luminosity function at z=7-9 incorporating the 2012 Hubble Ultra Deep Field imaging
• A Critical Assessment of Photometric Redshift Methods: A CANDELS Investigation
• Dust Obscuration and Metallicity at High Redshift: New Inferences from UV, H-alpha, and 8 Micron Observations of z~2 Star-Forming Galaxies
• The Great Observatories Origins Deep Survey. VLT/FORS2 Spectroscopy in the GOODS-South Field: Part III
• CANDELS Multiwavelength catalogs: Source Identification and Photometry in the CANDELS UKIDSS Ultra-Deep Survey Field
• The Subaru/XMM-Newton Deep Survey (SXDS) - II. Optical Imaging and Photometric Catalogs
• CANDELS: The Evolution of Galaxy Rest-Frame Ultraviolet Colors from z = 8 to 4
• The HST eXtreme Deep Field XDF: Combining all ACS and WFC3/IR Data on the HUDF Region into the Deepest Field Ever
• The Hubble Space Telescope Wide Field Camera 3 Early Release Science data: Panchromatic Faint Object Counts for 0.2-2 microns wavelength
• The Great Observatories Origins Deep Survey - VLT/VIMOS Spectroscopy in the GOODS-South Field: Part II
• The Great Observatories Origins Deep Survey. VLT/VIMOS Spectroscopy in the GOODS-South Field
• Galaxy Size Evolution at High Redshift and Surface Brightness Selection Effects: Constraints from the Hubble Ultra Deep Field
• Very blue UV-continuum slopes of low luminosity z~7 galaxies from WFC3/IR: Evidence for extremely low metallicities?
• GOODS-Herschel Measurements of the Dust Attenuation of Typical Star-Forming Galaxies at High Redshift: Observations of UV-Selected Galaxies at z~2
• On the Stellar Populations and Evolution of Star-Forming Galaxies at 6.3 < z < 8.6
• The UV continua and inferred stellar populations of galaxies at z ~ 7 - 9 revealed by the Hubble Ultra Deep Field 2012 campaign
• The 2012 Hubble Ultra Deep Field (UDF12): Observational Overview
• A critical analysis of the UV-continuum slopes of high-redshift galaxies; no evidence (yet) for extreme stellar populations at z > 6
• The luminosity function, halo masses and stellar masses of luminous Lyman-break galaxies at redshifts 5<z<6
• The UV Properties of Star Forming Galaxies I: HST WFC3 Observations of Very-high Redshift Galaxies
• Lyman break galaxies, Lya emitters and a radio galaxy in a protocluster at z=4.1
• The blue UV slopes of z~4 Lyman break galaxies: implications for the corrected star formation rate density
• Interpreting the observed UV continuum slopes of high-redshift galaxies
• Lyman Alpha Emitters and Lyman Break Galaxies: dichotomous twins?
• The unbiased measurement of UV spectral slopes in low luminosity galaxies at z=7
• The Color Magnitude Distribution of Field Galaxies to z~3: the evolution and modeling of the blue sequence
• New insights on the accuracy of photometric redshift measurements

Cited by in corpus (53)

• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• The Interstellar Medium In Galaxies Seen A Billion Years After The Big Bang
• UV-Continuum Slopes of >4000 z~4-8 Galaxies from the HUDF/XDF, HUDF09, ERS, CANDELS-South, and CANDELS-North Fields
• The mass evolution of the first galaxies: stellar mass functions and star formation rates at $4<z<7$ in the CANDELS GOODS-South field
• Line Emitting Galaxies Beyond a Redshift of 7: An Improved Method for Estimating the Evolving Neutrality of the Intergalactic Medium
• A redshift-independent efficiency model: star formation and stellar masses in dark matter halos at z>4
• The z~6 Luminosity Function Fainter than -15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties
• Z > 7 galaxies with red Spitzer/IRAC [3.6]-[4.5] colors in the full CANDELS data set: the brightest-known galaxies at Z ~ 7-9 and a probable spectroscopic confirmation at Z=7.48
• A lack of evolution in the very bright-end of the galaxy luminosity function from z = 8-10
• The Lyman-Continuum Photon Production Efficiency xi_{ion} of z~4-5 Galaxies from IRAC-based Halpha Measurements: Implications for the Escape Fraction and Cosmic Reionization
• The bright end of the galaxy luminosity function at z ~ 7: before the onset of mass quenching?
• The galaxy luminosity function at z ~ 6 and evidence for rapid evolution in the bright end from z ~ 7 to 5
• Semi-analytic forecasts for JWST - I. UV luminosity functions at z = 4 - 10
• The JWST Extragalactic Mock Catalog: Modeling galaxy populations from the UV through the near-IR over thirteen billion years of cosmic history
• Galaxy Stellar Mass Functions from z~10 to z~6 using the Deepest Spitzer/IRAC Data: No Significant Evolution in the Stellar-to-Halo Mass Ratio of Galaxies in the First Gyr of Cosmic Time
• Unveiling the nature of bright z ~ 7 galaxies with the Hubble Space Telescope
• Essential physics of early galaxy formation
• Observational Searches for Galaxies at z > 6
• First Frontier Field Constraints on the Cosmic Star-Formation Rate Density at z~10 - The Impact of Lensing Shear on Completeness of High-Redshift Galaxy Samples
• The Bright End of the z~9 and z~10 UV Luminosity Functions using all five CANDELS Fields
• Dust attenuation in 2<z<3 star-forming galaxies from deep ALMA observations of the Hubble Ultra Deep Field
• The VANDELS ESO public spectroscopic survey
• The ultraviolet continuum slopes ($\beta$) of galaxies at $\mathbf{z}\simeq 8-16$ from JWST and ground-based near-infrared imaging
• The Brightest $z\gtrsim 8$ Galaxies over the COSMOS UltraVISTA Field
• A Search for H-Dropout Lyman Break Galaxies at z~12-16
• New constraints on dust emission and UV attenuation of z=6.5-7.5 galaxies from millimeter observations
• Obscured star-formation in bright z ~ 7 Lyman-break galaxies
• The MUSE Hubble Ultra Deep Field Survey X. Ly$\alpha$ Equivalent Widths at $2.9<z<6.6$
• The First Billion Years project: constraining the dust attenuation law of star-forming galaxies at z $\simeq$ 5
• Newly Discovered Bright z~9-10 Galaxies and Improved Constraints on Their Prevalence Using the Full CANDELS Area
• Extremely Small Sizes for Faint z~2-8 Galaxies in the Hubble Frontier Fields: A Key Input For Establishing their Volume Density and UV Emissivity
• Quantifying the UV continuum slopes of galaxies to z~10 using deep Hubble and Spitzer/IRAC observations
• UV Spectral-Slopes at $z=6-9$ in the Hubble Frontier Fields: Lack of Evidence for Unusual or Pop III Stellar Populations
• Interpreting the evolution of galaxy colours from $z=8$ to $z=5$
• Constraints on the Lyman continuum escape fraction for faint star forming galaxies
• The VIMOS Ultra Deep Survey: Ly$\alpha$ Emission and Stellar Populations of Star-Forming Galaxies at 2<z<2.5
• HST imaging of the brightest z~8-9 galaxies from UltraVISTA: the extreme bright end of the UV luminosity function
• Detection of three Gamma-Ray Burst host galaxies at $z\sim 6$
• The VANDELS survey: A strong correlation between Ly$\alpha$ equivalent width and stellar metallicity at $3\le \mathbf{z}\le 5$
• HST followup observations of two bright z ~ 8 candidate galaxies from the BoRG pure-parallel survey
• The rapid transition from star-formation to AGN dominated rest-frame UV light at z ~ 4
• Dark-ages Reionization and Galaxy Formation Simulation -- XIX: Predictions of infrared excess and cosmic star formation rate density from UV observations
• Effects of self-consistent rest-ultraviolet colours in semi-empirical galaxy formation models
• The UV spectral slope beta and stellar population of most active star-forming galaxies at z~4
• Evolution of the UV slope of galaxies at cosmic morning (z > 4): the properties of extremely blue galaxies
• High-Redshift Galaxy Surveys and the Reionization of the Universe
• Cosmic Reionization On Computers. Ultraviolet Continuum Slopes and Dust Opacities in High Redshift Galaxies
• Observed UV continuum slopes ($\beta$) of galaxies at $z=0.40-0.75$ in the GOODS-north field
• Probing the nature of Dark Matter through the metal enrichment of the intergalactic medium
• Dust emission from the bulk of galaxies at the Epoch of Reionization
• "Zombie" or active? An alternative explanation to the properties of star-forming galaxies at high redshift
• Testing Photometric Techniques for Measuring the Rest-Frame UV Spectral Slope Against JWST PRISM Spectroscopy
• The Cosmic Rush Hour: Rapid Formation of Bright, Massive, Disky, Star-Forming Galaxies as Signatures of Early-Universe Physics