HST imaging of the brightest z~8-9 galaxies from UltraVISTA: the extreme bright end of the UV luminosity function

Abstract

We report on the discovery of three especially bright candidate $z_{phot}\gtrsim 8$ galaxies. Five sources were targeted for follow-up with HST/WFC3, selected from a larger sample of 16 bright ($24.8\lesssim H\lesssim 25.5$~mag) candidate $z\gtrsim 8$ LBGs identified over the 1.6 degrees${}^2$ of the COSMOS/UltraVISTA field. These were identified as Y and J dropouts by leveraging the deep (Y-to-$K_S\sim 25.3-24.8$~mag, $5\sigma$) NIR data from the UltraVISTA DR3 release, deep ground based optical imaging from the CFHTLS and Subaru 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 HyperSuprime Cam g, r, i, z and Y band data, we confirm that 3/5 galaxies have robust $z_{phot}\sim 8.0-8.7$, consistent with the initial selection. The remaining 2/5 galaxies have a nominal $z_{phot}\sim 2$. However, if we use the HST data alone, these objects have increased probability of being at $z\sim 9$. Furthermore, we measure mean UV continuum slopes $\beta =-1.91\pm 0.26$ for the three $z\sim 8-9$ galaxies, marginally bluer than similarly luminous $z\sim 4-6$ in CANDELS but consistent with previous measurements of similarly luminous galaxies at $z\sim 7$. The circularized effective radius for our brightest source is $0.9\pm 0.2$ kpc, similar to previous measurements for a bright $z\sim 11$ galaxy and bright $z\sim 7$ galaxies. Finally, enlarging our sample to include the six brightest $z\sim 8$ LBGs identified over UltraVISTA (i.e., including three other sources from Labbe et al. 2017, in prep.) we estimate for the first time the volume density of galaxies at the extreme bright ($M_{UV}\sim -22$~mag) end of the $z\sim 8$ UV LF. Despite this exceptional result, the still large statistical uncertainties do not allow us to discriminate between a Schechter and a double power-law form.

arXiv commentResubmitting after addressing the referee's comments. Appendix B includes the additional 3 sources from Labbe+2017, used for the LF estimate

References in corpus (88)

• Stellar population synthesis at the resolution of 2003
• Star Formation in Galaxies Along the Hubble Sequence
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Detailed Structural Decomposition of Galaxy Images
• 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
• The Cosmic Evolution Survey (COSMOS) -- Overview
• EAZY: A Fast, Public Photometric Redshift Code
• Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• The Hubble Deep Field: Observations, Data Reduction, and Galaxy Photometry
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• The Hubble Ultra Deep Field
• UltraVISTA: a new ultra-deep near-infrared survey in COSMOS
• The 3D-HST Survey: Hubble Space Telescope WFC3/G141 grism spectra, redshifts, and emission line measurements for $\sim 100,000$ galaxies
• The Evolution of the Galaxy Rest-Frame Ultraviolet Luminosity Function Over the First Two Billion Years
• 3D-HST: A wide-field grism spectroscopic survey with the Hubble Space Telescope
• The Frontier Fields: Survey Design
• The Spitzer Legacy Survey of the HST-ACS 2 sq. deg. COSMOS Field: survey strategy and first analysis
• UV Luminosity Functions from 132 z~7 and z~8 Lyman-Break Galaxies in the ultra-deep HUDF09 and wide-area ERS WFC3/IR Observations
• A Remarkably Luminous Galaxy at z=11.1 Measured with Hubble Space Telescope Grism Spectroscopy
• The Chandra COSMOS Legacy survey: overview and point source catalog
• 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
• Keck Spectroscopy of 3<z<7 Faint Lyman Break Galaxies: The Importance of Nebular Emission in Understanding the Specific Star Formation Rate and Stellar Mass Density
• H-alpha Observations of a Large Sample of Galaxies at z~2: Implications for Star Formation in High Redshift Galaxies
• A new multi-field determination of the galaxy luminosity function at z=7-9 incorporating the 2012 Hubble Ultra Deep Field imaging
• A new catalog of photometric redshifts in the Hubble Deep Field
• L and T Dwarf Models and the L to T Transition
• The VLA-COSMOS 3 GHz Large Project: Continuum data and source catalog release
• The Cosmic Evolution Survey (COSMOS): Subaru Observations of the HST COSMOS Field
• Lyman-alpha and CIII] Emission in z=7-9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?
• The Chandra COSMOS Legacy survey: optical/IR identifications
• 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
• 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
• A Cosmic Variance Cookbook
• The mass evolution of the first galaxies: stellar mass functions and star formation rates at $4<z<7$ in the CANDELS GOODS-South field
• Evidence for Ubiquitous, High-EW Nebular Emission in z~7 Galaxies: Towards a Clean Measurement of the Specific Star Formation Rate using a Sample of Bright, Magnified Galaxies
• The XMM-Newton wide-field survey in the COSMOS field. The point-like X-ray source catalogue
• The Spectral Energy Distributions Of z~8 Galaxies From The IRAC Ultra Deep Fields: Emission Lines, Stellar Masses, And Specific Star Formation Rates At 650 Myr
• Lyman-alpha Emission from a Luminous z=8.68 Galaxy: Implications for Galaxies as Tracers of Cosmic Reionization
• The UV Luminosity Function of star-forming galaxies via dropout selection at redshifts z ~ 7 and 8 from the 2012 Ultra Deep Field campaign
• The z~6 Luminosity Function Fainter than -15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties
• Structure and Morphologies of z~7-8 Galaxies from ultra-deep WFC3/IR Imaging of the HUDF
• The z = 9-10 galaxy population in the Hubble Frontier Fields and CLASH surveys: The z=9 LF and further evidence for a smooth decline in UV luminosity at z >= 8
• 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
• 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
• 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
• Star formation rates and stellar masses of z=7-8 galaxies from IRAC observations of the WFC3/IR ERS and the HUDF field
• The UV continua and inferred stellar populations of galaxies at z ~ 7 - 9 revealed by the Hubble Ultra Deep Field 2012 campaign
• CARS: the CFHTLS-Archive-Research Survey; I. Five-band multi-colour data from 37 sq. deg. CFHTLS-Wide observations
• Simultaneous Multicolor Detection of Faint Galaxies in the Hubble Deep Field
• CARS: The CFHTLS-Archive-Research Survey II. Weighing dark matter halos of Lyman-break galaxies at z=3-5
• High-precision Photometric Redshifts from Spitzer/IRAC: Extreme [3.6]-[4.5] Colors Identify Galaxies in the Redshift Range z~6.6-6.9
• New redshift z ~ 9 galaxies in the Hubble Frontier Fields: Implications for early evolution of the UV luminosity density
• The Redshift and Mass Dependence on the Formation of The Hubble Sequence at z>1 from CANDELS/UDS
• Unveiling the nature of bright z ~ 7 galaxies with the Hubble Space Telescope
• Spitzer IRAC confirmation of z_850-dropout galaxies in the Hubble Ultra Deep Field: stellar masses and ages at z~7
• The Brightest of Reionizing Galaxies Survey: Constraints on the Bright End of the z~8 Luminosity Function
• T-PHOT: A new code for PSF-matched, prior-based, multiwavelength extragalactic deconfusion photometry
• The Physical Nature of Rest-UV Galaxy Morphology During the Peak Epoch of Galaxy Formation
• Ultradeep Infrared Array Camera Observations of sub-L* z~7 and z~8 Galaxies in the Hubble Ultra Deep Field: the Contribution of Low-Luminosity Galaxies to the Stellar Mass Density and Reionization
• The Brightest Of Reionizing Galaxies Survey: Design and Preliminary Results
• Evolution of the Sizes of Galaxies over 7<z<12 Revealed by the 2012 Hubble Ultra Deep Field Campaign
• The UV Properties of Star Forming Galaxies I: HST WFC3 Observations of Very-high Redshift Galaxies
• The Bright End of the z~9 and z~10 UV Luminosity Functions using all five CANDELS Fields
• The Luminosity Function at z~8 from 97 Y-band dropouts: Inferences About Reionization
• First Results from the 3D-HST Survey: The Striking Diversity of Massive Galaxies at z>1
• Star formation in galaxies at z~4-5 from the SMUVS survey: a clear starburst/main-sequence bimodality for Halpha emitters on the SFR-M* plane
• Ultradeep IRAC Imaging Over The HUDF And GOODS-South: Survey Design And Imaging Data Release
• The blue UV slopes of z~4 Lyman break galaxies: implications for the corrected star formation rate density
• Non-parametric analysis of the rest-frame UV sizes and morphological disturbance amongst L* galaxies at 4<z<8
• The morphologies of massive galaxies from z~3 - Witnessing the 2 channels of bulge growth
• Probing Very Bright End of Galaxy Luminosity Function at z >~ 7 Using Hubble Space Telescope Pure Parallel Observations
• The Sizes of Candidate $z\sim 9-10$ Galaxies: confirmation of the bright CANDELS sample and relation with luminosity and mass
• The Bivariate Size-luminosity Relations for Lyman Break Galaxies at z ~ 4 - 5
• The colour distribution of galaxies at redshift five
• Physical Properties of Spectroscopically-Confirmed Galaxies at z >= 6. I. Basic Characteristics of the Rest-Frame UV Continuum and Lyman-alpha emission
• Quantifying the UV continuum slopes of galaxies to z~10 using deep Hubble and Spitzer/IRAC observations
• Bright galaxies at Hubble's redshift detection frontier: Preliminary results and design from the redshift z~9-10 BoRG pure-parallel HST survey
• Size evolution of star-forming galaxies with $2<z<4.5$ in the VIMOS Ultra-Deep Survey
• The rest-frame optical (900nm) galaxy luminosity function at z~4-7: abundance matching points to limited evolution in the Mstar/Mhalo ratio at z>4
• A Rest-frame Optical View on z~4 Galaxies I: Color and Age Distributions from Deep IRAC Photometry of the IUDF10 and GOODS Surveys
• Mean Halpha+[NII]+[SII] EW Inferred for Star-Forming Galaxies at z=5.1-5.4 Using High-Quality Spitzer/IRAC Photometry
• Hubble Space Telescope Observations of Field Ultracool Dwarfs at High Galactic Latitude
• Milky Way Red Dwarfs in the BoRG Survey; Galactic scale-height and the distribution of dwarfs stars in WFC3 imaging
• Galaxy candidates at z ~ 10 in archival data from the Brightest of Reionizing Galaxies (BoRG[z8]) survey

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• COSMOS-DASH: The Evolution of the Galaxy Size-Mass Relation Since z~3 from new Wide Field WFC3 Imaging Combined with CANDELS/3DHST
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• The Brightest $z\gtrsim 8$ Galaxies over the COSMOS UltraVISTA Field
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• The ALMA REBELS Survey: Efficient Ly$\alpha$ Transmission of UV-Bright z$\simeq$7 Galaxies from Large Velocity Offsets and Broad Line Widths
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• The Super Eight Galaxies: Properties of a Sample of Very Bright Galaxies at $7<z<8$
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• COSMOS2020: UV selected galaxies at $z\ge 7.5$
• HST followup observations of two bright z ~ 8 candidate galaxies from the BoRG pure-parallel survey
• The Spitzer/IRAC Legacy over the GOODS Fields: Full-Depth 3.6, 4.5, 5.8 and 8.0um Mosaics and Photometry for > 9000 Galaxies at z~3.5-10 from the GOODS Re-ionization Era wide-Area Treasury from Spitzer (GREATS)
• Galaxy Morphologies Revealed with Subaru HSC and Super-Resolution Techniques I: Major Merger Fractions of L_UV~3-15 L_UV* Dropout Galaxies at z~4-7
• The UV luminosity functions of Bright z>8 Galaxies: Determination from ~0.41 deg2 of HST Observations along ~sim 300 independent sightlines
• The Cosmic Web Around The Brightest Galaxies During The Epoch Of Reionization
• The UV luminosity function at 0.6 < z < 1 from UVCANDELS
• Investigating the physical properties of galaxies in the Epoch of Reionization with MIRI/JWST spectroscopy
• The archival discovery of a strong Lyman-$\alpha$ and [CII] emitter at z = 7.677
• Galaxy luminosity functions at redshifts 0.6 to 1.2 in the Chandra Deep Field South
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• Observing EAGLE galaxies with JWST: predictions for Milky Way progenitors and their building blocks
• Euclid: Discovery of bright $z\simeq 7$ Lyman-break galaxies in UltraVISTA and Euclid COSMOS