Sub-kiloparsec Imaging of Lyman-alpha Emission in a Low Mass, Highly Ionized, Gravitationally Lensed Galaxy at z = 1.84

Abstract

Low mass, low metallicity galaxies at low to moderate ($z\lesssim 3$) redshifts offer the best opportunity for detailed examination of the interplay between massive stars, ionizing radiation and gas in sources similar to those that likely reionized the universe. We present new narrowband Hubble Space Telescope observations of Ly$\alpha$ emission and the adjacent ultraviolet (UV) continuum in the low mass ($M_{\star }=2\times 10^8$ M${}_{\odot }$), low metallicity ($Z\sim 1/20$ Z${}_{\odot }$) and highly ionized gravitationally lensed galaxy SL2S J02176$-$0513 at $z=1.844$. The galaxy has strong Ly$\alpha$ emission with photometric equivalent width $W_{\mathrm{Ly}\alpha }^{\mathrm{phot}}=218\pm 12$ Å, at odds with the Ly$\alpha$ escape fraction of 10%. However, the spectroscopic Ly$\alpha$ profile suggests the presence of broad absorption underlying the emission, and the total equivalent width is consistent with the escape fraction once this underlying absorption is included. The Ly$\alpha$ emission is more spatially extended than the UV continuum, and the 0.14" spatial resolution of HST coupled with the magnification of gravitational lensing enables us to examine the distribution of Ly$\alpha$ and the UV continuum on sub-kiloparsec scales. We find that the peaks of the Ly$\alpha$ emission and the UV continuum are offset by 650 pc, and there is no Ly$\alpha$ emission arising from the region with the strongest UV light. Our combined spectroscopic and imaging data imply a significant range in neutral hydrogen column density across the object. These observations offer indirect support for a model in which ionizing radiation escapes from galaxies through channels with low column density of neutral gas.

arXiv comment13 pages, 7 figures. Revised version resubmitted to ApJ

References in corpus (60)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• 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
• Rest-Frame Ultraviolet Spectra of z~3 Lyman Break Galaxies
• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• The Rest Frame Optical Spectra of Lyman Break Galaxies: Star Formation, Extinction, Abundances, and Kinematics
• The 3D-HST Survey: Hubble Space Telescope WFC3/G141 grism spectra, redshifts, and emission line measurements for $\sim 100,000$ galaxies
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• Diffuse Lyman Alpha Emitting Halos: A Generic Property of High Redshift Star Forming Galaxies
• Lyman-alpha and CIII] Emission in z=7-9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?
• The population of galaxy-galaxy strong lenses in forthcoming optical imaging surveys
• Detection of high Lyman continuum leakage from four low-redshift compact star-forming galaxies
• Low-redshift Lyman continuum leaking galaxies with high [OIII]/[OII] ratios
• The Keck Lyman Continuum Spectroscopic Survey (KLCS): The Emergent Ionizing Spectrum of Galaxies at $z\sim 3$
• Physical Conditions in a Young, Unreddened, Low Metallicity Galaxy at High Redshift
• Concordance models of reionization: implications for faint galaxies and escape fraction evolution
• Using Lyman-alpha to detect galaxies that leak Lyman continuum
• Extended Lyman alpha haloes around individual high-redshift galaxies revealed by MUSE
• Lyman Alpha Emitting Galaxies as a Probe of Reionization
• Lyman continuum leaking from the compact star-forming dwarf galaxy J0925+1403
• Extreme Feedback and the Epoch of Reionization: Clues in the Local Universe
• Spectroscopic detection of CIV in a galaxy at z=7.045: Implications for the ionizing spectra of reionization-era galaxies
• Ly$\alpha$ emission from Green Peas: the role of circumgalactic gas density, covering, and kinematics
• J1154+2443: a low-redshift compact star-forming galaxy with a 46 per cent leakage of Lyman continuum photons
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• Ultraviolet Emission Lines in Young Low Mass Galaxies at z~2: Physical Properties and Implications for Studies at z>7
• Spectroscopic detections of CIII]1909 at z~6-7: A new probe of early star forming galaxies and cosmic reionisation
• Ly$\alpha$ profile, dust, and prediction of Ly$\alpha$ escape fraction in Green Pea Galaxies
• Monte Carlo Simulation of Lyman Alpha Scattering and Application to Damped Lyman Alpha Systems
• Direct Lyman continuum and Lyman-alpha escape observed at redshift 4
• Escape of Lyman continuum radiation from local galaxies - Detection of leakage from the young starburst Tol 1247-232
• Carbon and Oxygen Abundances in Low Metallicity Dwarf Galaxies
• The Spectroscopic Properties of Lyα-Emitters at z $\approx$ 2.7: Escaping Gas and Photons from Faint Galaxies
• The Relationship Between Stellar Populations and Lyman Alpha Emission in Lyman Break Galaxies
• Diffuse Lyman-alpha Halos around Galaxies at z=2.2-6.6: Implications for Galaxy Formation and Cosmic Reionization
• Direct Detection of Lyman Continuum Escape from Local Starburst Galaxies with the Cosmic Origins Spectrograph
• The Lyman alpha Reference Sample: II. HST imaging results, integrated properties and trends
• Diffuse Lyman Alpha Haloes around Lyman Alpha Emitters at z=3: Do Dark Matter Distributions Determine the Lyman Alpha Spatial Extents?
• The Ultraviolet Spectrum of the Gravitationally Lensed Galaxy `The Cosmic Horseshoe': A Close-up of a Star-forming Galaxy at z = 2
• A Window On The Earliest Star Formation: Extreme Photoionization Conditions of a High-Ionization, Low-Metallicity Lensed Galaxy at z~2
• SILVERRUSH. V. Census of Lya, [OIII]5007, Ha, and [CII]158um Line Emission with ~1000 LAEs at z=4.9-7.0 Revealed with Subaru/HSC
• Accurately predicting the escape fraction of ionizing photons using restframe ultraviolet absorption lines
• The Lyman Alpha Reference Sample: V. The impact of neutral ISM kinematics and geometry on Lyman Alpha escape
• High-resolution spectroscopy of a young, low-metallicity optically-thin L=0.02L* star-forming galaxy at z=3.12
• The Sunburst Arc: Direct Lyman α escape observed in the brightest known lensed galaxy
• Neutral gas properties of Lyman continuum emitting galaxies: column densities and covering fractions from UV absorption lines
• Linking Ly-alpha and Low-Ionization Transitions at Low Optical Depth
• Intense CIV and HeII Emission in z~0 Galaxies: Probing High-Energy Ionizing Photons
• Statistical Properties of Diffuse Lyman-alpha Halos around Star-forming Galaxies at z~2
• Spectroscopic Constraints on UV Metal Line Emission at z~6-9: The Nature of Lyman-alpha Emitting Galaxies in the Reionization-Era
• 3D-HST Grism Spectroscopy of a Gravitationally Lensed, Low-metallicity Starburst Galaxy at z=1.847
• Feedback in low-mass galaxies in the early Universe
• Kinematics and Optical Depth in the Green Peas: Suppressed Superwinds in Candidate LyC Emitters
• A High Fraction of Ly-alpha-Emitters Among Galaxies with Extreme Emission Line Ratios at z ~ 2
• Modeling $237$ Lyman-$\alpha$ spectra of the MUSE-Wide survey
• Investigating Nearby Star-Forming Galaxies in the Ultraviolet with HST/COS Spectroscopy. I: Spectral Analysis and Interstellar Abundance Determinations
• The Kinematics of Extended Lyman-alpha Emission in a Low Mass, Low Metallicity Galaxy at z = 2.3
• The Lyman Continuum Escape and ISM properties in Tololo 1247-232 - New Insights from HST and VLA
• Neutral Gas Properties and Ly$\alpha$ Escape in Extreme Green Pea Galaxies
• The mass profile of early-type galaxies in overdense environments: the case of the double source plane gravitational lens SL2SJ02176-0513

Cited by in corpus (14)

• The Lyman Continuum Escape Survey -- II: Ionizing Radiation as a Function of the [OIII]/[OII] Line Ratio
• Diverse properties of Ly-alpha emission in low-redshift compact star-forming galaxies with extremely high [OIII]/[OII] ratios
• The MUSE Deep Lensed Field on the Hubble Frontier Field MACS~J0416
• Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-alpha emitters
• The Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS) : I. Characterisation of extended Lyman-alpha haloes and spatial offsets
• Rest-frame UV Properties of Luminous Strong Gravitationally Lensed Ly$\alpha$ Emitters from the BELLS GALLERY Survey
• Metal-Enriched Neutral Gas Reservoir around a Strongly-lensed, Low-mass Galaxy at $z=4$ Identified by JWST/NIRISS and VLT/MUSE
• The nature of CR7 revealed with MUSE: a young starburst powering extended Lyman-$\alpha$ emission at z=6.6
• Uncovering the physical origin of the prominent Lyman-$\alpha$ emission and absorption in GS9422 at $z=5.943$
• Revealing the Nature of a Lyman-$\alpha$ Halo in a Strongly Lensed Interacting System at $z=2.92$
• Resolved galactic superwinds reconstructed around their host galaxies at z>3
• Ultra-faint [CII] emission in a redshift = 2 gravitationally-lensed metal-poor dwarf galaxy
• The miniJPAS Survey: Detection of double-core Lyα morphology of two high-redshift (z>3) QSOs
• Far-infrared observations of dust in Ly$\alpha$ emitters at z=2-6