Discovery of an unusually compact lensed Lyman Break Galaxy from the Hyper Suprime-Cam Survey

Abstract

We report the serendipitous discovery of HSC J0904$-$0102, a quadruply-lensed Lyman break galaxy (LBG) in the Survey of Gravitationally-lensed Objects in Hyper Suprime-Cam Imaging (SuGOHI). Owing to its point-like appearance, the source was thought to be a lensed active galactic nucleus. We obtained follow-up spectroscopic data with the Gemini Multi-Object Spectrographs on the Gemini South Telescope, which confirmed this to be a lens system. The deflecting foreground galaxy is a typical early-type galaxy at a high redshift of $z_{\ell }=0.957$ with stellar velocity dispersion ${\sigma }_v=259\pm 56$ km~s${}^{-1}$. The lensed source is identified as an LBG at $z_{\mathrm{s}}=3.403$, based on the sharp drop bluewards of Ly$\alpha$ and other absorption features. A simple lens mass model for the system, assuming a singular isothermal ellipsoid, yields an Einstein radius of ${\theta }_{\mathrm{Ein}}=1.23^{\prime \prime }$ and a total mass within the Einstein radius of $M_{\mathrm{Ein}}=(5.55\pm 0.24)\times 10^{11}{M}_{\odot }$ corresponding to a velocity dispersion of ${\sigma }_{\mathrm{SIE}}=283\pm 3$ km~s${}^{-1}$, which is in good agreement with the value derived spectroscopically. The most isolated lensed LBG image has a magnification of $\sim 6.5$. In comparison with other lensed LBGs and typical $z\sim 4$ LBG populations, HSC J0904$-$0102 is unusually compact, an outlier at $>2\sigma$ confidence. Together with a previously discovered SuGOHI lens, HSC J1152$+$0047, that is similarly compact, we believe that the HSC Survey is extending LBG studies down to smaller galaxy sizes.

arXiv commentAccepted for publication on MNRAS, 10 pages, 6 figures

References in corpus (60)

• emcee: The MCMC Hammer
• Stellar population synthesis at the resolution of 2003
• Star Formation in Galaxies Along the Hubble Sequence
• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• Detailed Structural Decomposition of Galaxy Images
• Accurate photometric redshifts for the CFHT Legacy Survey calibrated using the VIMOS VLT Deep Survey
• MILES: A Medium resolution INT Library of Empirical Spectra
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• Rest-Frame Ultraviolet Spectra of z~3 Lyman Break Galaxies
• The Hyper Suprime-Cam SSP Survey: Overview and Survey Design
• Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North
• The Pan-STARRS1 Surveys
• Accurate masses for dispersion-supported galaxies
• First Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• A Large Structure of Galaxies At Redshift z~3 and its Cosmological Implications
• A Survey of Star-Forming Galaxies in the z=1.4-2.5 `Redshift Desert': Overview
• A Steep Faint-End Slope of the UV Luminosity Function at z~2-3: Implications for the Global Stellar Mass Density and Star Formation in Low Mass Halos
• Second Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• Galaxies and Intergalactic Matter at Redshift z~3: Overview
• The Ultraviolet Spectrum of MS 1512-cB58: An Insight into Lyman Break Galaxies
• New Observations of the Interstellar Medium in the Lyman Break Galaxy MS 1512-cB58
• The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA Derived Quantities, Data Visualization Tools and Stellar Library
• The Mass Distribution of SDSS J1004+4112 Revisited
• The fourth data release of the Kilo-Degree Survey: ugri imaging and nine-band optical-IR photometry over 1000 square degrees
• A Counts-in-Cells Analysis of Lyman-break Galaxies at z~3
• The SL2S Galaxy-scale Lens Sample. IV. The dependence of the total mass density profile of early-type galaxies on redshift, stellar mass, and size
• Great Optically Luminous Dropout Research Using Subaru HSC (GOLDRUSH). I. UV Luminosity Functions at $z\sim 4-7$ Derived with the Half-Million Dropouts on the 100 deg${}^2$ Sky
• An optically-selected cluster catalog at redshift 0.1<z<1.1 from the Hyper Suprime-Cam Subaru Strategic Program S16A data
• A Keck Survey for Gravitationally-Lensed Lyman-alpha Emitters in the Redshift Range 8.5 < z < 10.4: New Constraints on the Contribution of Low Luminosity Sources to Cosmic Reionization
• The Ultraviolet Spectrum of the Gravitationally Lensed Galaxy `The Cosmic Horseshoe': A Close-up of a Star-forming Galaxy at z = 2
• Keck Deep Fields. II. The UV Galaxy Luminosity Function at z~4, 3, and 2
• The SL2S Galaxy-scale Lens Sample. III. Lens Models, Surface Photometry and Stellar Masses for the final sample
• The Emission Line Properties of Gravitationally-lensed 1.5 < z < 5 Galaxies
• The Cosmic Horseshoe: Discovery of an Einstein Ring around a Giant Luminous Red Galaxy
• A Hubble & Spitzer Space Telescope Survey for Gravitationally-Lensed Galaxies: Further Evidence for a Significant Population of Low Luminosity Galaxies beyond Redshift Seven
• Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). I. Automatic search for galaxy-scale strong lenses
• Detection of PAH and Far-Infrared Emission from the Cosmic Eye: Probing the Dust and Star Formation of Lyman Break Galaxies
• Molecular Gas in the Lensed Lyman Break Galaxy cB58
• A very bright, highly magnified Lyman-break galaxy at z=3.07
• The LSST Data Management System
• A Detailed Study of Gas and Star Formation in a Highly Magnified Lyman Break Galaxy at z=3.07
• Size bias and differential lensing of strongly lensed, dusty galaxies identified in wide-field surveys
• The 8 o'clock Arc: A Serendipitous Discovery of a Strongly Lensed Lyman Break Galaxy in the SDSS DR4 Imaging Data
• Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). II. Environments and Line-of-Sight Structure of Strong Gravitational Lens Galaxies to z ~ 0.8
• Survey of gravitationally-lensed objects in HSC imaging (SuGOHI). III. Statistical strong lensing constraints on the stellar IMF of CMASS galaxies
• A Study of Interstellar Gas and Stars in the Gravitationally Lensed Galaxy `The Cosmic Eye' from Rest-Frame Ultraviolet Spectroscopy
• The z=2.72 galaxy cB58: a gravitational fold arc lensed by the cluster MS 1512+36
• Identification of a Gravitationally Lensed z=2.515 Star-Forming Galaxy
• Two Lensed z~3 Lyman Break Galaxies Discovered in the SDSS Giant Arcs Survey
• Red nuggets grow inside-out: evidence from gravitational lensing
• Discovery of a high-redshift Einstein ring
• A High Resolution Atlas of Composite SDSS Galaxy Spectra
• A new quadruple gravitational lens from the Hyper Suprime-Cam Survey: the puzzle of HSC~J115252+004733
• On the contribution of large scale structure to strong gravitational lensing
• Gravitationally lensed high redshift galaxies in the field of 1E0657-56
• Gravitational lens candidates in the E-CDFS
• The Sextet Arcs: a Strongly Lensed Lyman Break Galaxy in the ACS Spectroscopic Galaxy Survey towards Abell 1689
• The evolution of late-type galaxies from CASSOWARY lensing systems
• A New Einstein Cross: A Highly Magnified, Intrinsically Faint Lyman-Alpha Emitter at z=2.7
• Discovery of a Very Bright and Intrinsically Very Luminous, Strongly Lensed Lyα Emitting Galaxy at z = 2.82 in the BOSS Emission-Line Lens Survey

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• Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). VI. Crowdsourced lens finding with Space Warps
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• Strong lensing in UNIONS: Toward a pipeline from discovery to modeling
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• HOLISMOKES -- IX. Neural network inference of strong-lens parameters and uncertainties from ground-based images
• HOLISMOKES -- X. Comparison between neural network and semi-automated traditional modeling of strong lenses
• HOLISMOKES XIII: Strong-lens candidates at all mass scales and their environments from the Hyper-Suprime Cam and deep learning
• Multi-band analysis of strong gravitationally lensed post-blue nugget candidates from the Kilo-Degree Survey
• HOLISMOKES XVI: Lens search in HSC-PDR3 with a neural network committee and post-processing for false-positive removal
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