COOL-LAMPS I. An Extraordinarily Bright Lensed Galaxy at Redshift 5.04

Abstract

We report the discovery of COOL J1241+2219, a strongly-lensed galaxy at redshift $z$=5.043$\pm$0.002 with observed magnitude $z_{AB}=20.47$, lensed by a moderate-mass galaxy cluster at $z$=1.001$\pm$0.001. COOL J1241+2219 is the brightest lensed galaxy currently known at optical and near-infrared wavelengths at $z$ $\gtrsim$ 5; it is $\sim$5 times brighter than the prior record-holder lensed galaxy, and several magnitudes brighter than the brightest unlensed galaxies known at these redshifts. It was discovered as part of COOL-LAMPS, a collaboration initiated to find strongly lensed systems in recent public optical imaging data. We characterise the lensed galaxy, as well as the central galaxy of the lensing cluster using ground-based $griz$JH imaging and optical spectroscopy. We report model-based magnitudes, and derive stellar masses, dust content, metallicity and star-formation rates via stellar-population synthesis modeling. Our lens mass modeling, based on ground-based imaging, implies a median source magnification of $\sim$30, which puts the stellar mass and star formation rate (in the youngest age bin, closest to the epoch of observation) at logM${}_{\ast }$ = $10.11_{-0.26}^{+0.21}$ and SFR = $27_{-9}^{+13}$ M${}_{\odot }$/yr, respectively. We constrain a star formation history for COOL J1241+2219 consistent with constant star formation across $\sim$1 Gyr of cosmic time, and that places this galaxy on the high-mass end of the star-forming main sequence. COOL J1241+2219 is 2-4 times more luminous than a galaxy with the characteristic UV luminosity at these redshifts. The UV continuum slope $\beta$= -2.2$\pm$0.2 places this galaxy on the blue side of the observed distribution of galaxies at $z$=5, although the lack of Ly$\alpha$ emission indicates dust sufficient to suppress this emission.

Accepted in the Astrophysical Journal, December 2020 (in production). 16 pages, 7 figures, 2 tables

References in corpus (19)

• Array Programming with NumPy
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• Galaxy Clusters Discovered via the Sunyaev-Zel'dovich Effect in the 2500-square-degree SPT-SZ survey
• A Bayesian approach to strong lensing modelling of galaxy clusters
• A Dust-Obscured Massive Maximum-Starburst Galaxy at a Redshift of 6.34
• Star formation in AEGIS field galaxies since z=1.1 . Staged galaxy formation, and a model of mass-dependent gas exhaustion
• The Star Formation Main Sequence in the Hubble Space Telescope Frontier Fields
• The MUSE Hubble Ultra Deep Field Survey: II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
• Resolved spectroscopy of gravitationally lensed galaxies: global dynamics and star-forming clumps on ~100pc scales
• ISM properties of a Massive Dusty Star-Forming Galaxy discovered at z ~ 7
• LinKS: Discovering galaxy-scale strong lenses in the Kilo-Degree Survey using Convolutional Neural Networks
• The Cosmic Horseshoe: Discovery of an Einstein Ring around a Giant Luminous Red Galaxy
• Gemini/GMOS Spectroscopy of 26 Strong Lensing Selected Galaxy Cluster Cores
• Star Formation at z=2.481 in the Lensed Galaxy SDSS J1110+6459: Star Formation down to 30 parsec scales
• Physical Characterization of an Unlensed Dusty Star-Forming Galaxy at $z=5.85$
• Lightcurves of Type Ia Supernovae from Near the Time of Explosion
• The Sloan Bright Arcs Survey : Discovery of Seven New Strongly Lensed Galaxies from z=0.66-2.94
• Star Formation at z=2.481 in the Lensed Galaxy SDSS J1110+6459, I: Lens Modeling and Source Reconstruction
• The FourStar Infrared Camera

Cited by in corpus (13)

• JWST/NIRCam Probes Young Star Clusters in the Reionization Era Sunrise Arc
• Assessing the sources of reionisation: a spectroscopic case study of a 30$\times$ lensed galaxy at $z\sim 5$ with Lyα, CIV, MgII, and [NeIII]
• Strong lens modelling: comparing and combining Bayesian neural networks and parametric profile fitting
• Identification of Galaxy-Galaxy Strong Lens Candidates in the DECam Local Volume Exploration Survey Using Machine Learning
• COOL-LAMPS III: Discovery of a 25".9 Separation Quasar Lensed by a Merging Galaxy Cluster
• The cold interstellar medium of a normal sub-$L^{\star }$ galaxy at the end of reionization
• A large population of strongly lensed faint submillimetre galaxies in future dark energy surveys inferred from JWST imaging
• Molecular gas budget and characterization of intermediate-mass star-forming galaxies at $z\approx 2-3$
• The CluMPR Galaxy Cluster-Finding Algorithm and DESI Legacy Survey Galaxy Cluster Catalogue
• Core Mass Estimates in Strong Lensing Galaxy Clusters Using a Single-Halo Lens Model
• COOL-LAMPS II. Characterizing the Size and Star Formation History of a Bright Strongly Lensed Early-Type Galaxy at Redshift 1.02
• COOL-LAMPS IV: A Sample of Bright Strongly-Lensed Galaxies at $3<z<4$
• COOL-LAMPS. VII. Quantifying Strong-lens Scaling Relations with 177 Cluster-scale Strong Gravitational Lenses in DECaLS