The Lyman Alpha Reference Sample XII: Morphology of extended Lyman alpha emission in star-forming galaxies

Abstract

We use Hubble space telescope data of 45 nearby star-forming galaxies to investigate properties of Lyman-alpha (Ly$\alpha$) halos, Ly$\alpha$ morphology, and the star-forming characteristics of galaxies. We study how the morphology of Ly$\alpha$ emission is related to other Ly$\alpha$ observables. Furthermore, we study the interdependencies of Ly$\alpha$ morphological quantities. We studied the spatial extent of Ly$\alpha$ using surface brightness profiles in i) using circular apertures and ii) within faint Ly$\alpha$ isophotes. We measured the average intensity and the size of the regions with a high star formation rate density. The morphology of the galaxies was quantified by computing centroid position, axis ratio, and position angle in the Ly$\alpha$, ultraviolet continuum, and I band maps. We found that galaxies with more extended star-forming regions possess larger Ly$\alpha$ halos. Furthermore, galaxies with more elongated Ly$\alpha$ morphology are also more extended in Ly$\alpha$. Our data suggest that Ly$\alpha$ bright galaxies appear rounder in their Ly$\alpha$ morphology, and there is less of a contribution from their Ly$\alpha$ halo to their overall luminosity. We compared our results with studies at high redshift and found that whilst the Ly$\alpha$ extent in the inner regions of the galaxies in our sample are similar to the high$-z$ Ly$\alpha$ emitters (LAEs), Ly$\alpha$ halos are more extended in high$-z$ LAEs. Our analysis suggests that the Ly$\alpha$ morphology affects the measurement of other observable quantities concerning Ly$\alpha$ emission, and some of the conclusions drawn from high redshift LAEs might be biased towards galaxies with specific Ly$\alpha$ shapes. In particular, faint Ly$\alpha$ emitters have larger Ly$\alpha$ scale lengths and halo fractions. This implies that faint Ly$\alpha$ emitters are harder to detect at high redshift than previously believed.

References in corpus (55)

• Astropy: A Community Python Package for Astronomy
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Star Formation in the Milky Way and Nearby Galaxies
• The Star Formation Law in Nearby Galaxies on Sub-Kpc Scales
• A concise reference to (projected) Sersic R^{1/n} quantities, including Concentration, Profile Slopes, Petrosian indices, and Kron Magnitudes
• Distant Radio Galaxies and their Environments
• Diffuse Lyman Alpha Emitting Halos: A Generic Property of High Redshift Star Forming Galaxies
• Extended Lyman alpha haloes around individual high-redshift galaxies revealed by MUSE
• Lyman Alpha Emitting Galaxies as a Probe of Reionization
• On the redshift-evolution of the Lyman-alpha escape fraction and the dust content of galaxies
• Lyman Alpha Radiative Transfer in a Multi-Phase Medium
• The MUSE 3D view of the Hubble Deep Field South
• Adaptive Binning of X-ray data with Weighted Voronoi Tesselations
• Very Extended X-ray and H-alpha Emission in M82: Implications for the Superwind Phenomenon
• Extended Ly-alpha emission from a damped Ly-alpha absorber at z = 1.93, and the relation between DLAs and Lyman-break 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
• Nearly all the sky is covered by Lyman-alpha emission around high redshift galaxies
• Lyman-alpha emission properties of simulated galaxies: interstellar medium structure and inclination effects
• The Lyman alpha Reference Sample: II. HST imaging results, integrated properties and trends
• Studying the YMC population of M83: how long clusters remain embedded, their interaction with the ISM and implications for GC formation theories
• The Lyman alpha morphology of local starburst galaxies: release of calibrated images
• Detection of Lyman-alpha Emitting Galaxies at Redshift z=4.55
• Lyman alpha emission in starbursts: implications for galaxies at high redshift
• The production and escape of Lyman-Continuum radiation from star-forming galaxies at z~2 and their redshift evolution
• The Lyman-alpha Reference Sample: I. Survey outline and first results for Markarian 259
• The Lyman Alpha Reference Sample: V. The impact of neutral ISM kinematics and geometry on Lyman Alpha escape
• New Insights on Ly-alpha and Lyman Continuum Radiative Transfer in the Greenest Peas
• Lyman alpha Resonant Scattering in Young Galaxies - Predictions from Cosmological Simulations
• On the Detectability of Lyman-alpha Emission in Star-forming Galaxies: The Role of Dust
• The effect of dust geometry on the Lyman-alpha output of galaxies
• Identification of a Galaxy Responsible for a High-Redshift Damped Ly-alpha Absorption System
• A physically motivated definition for the size of galaxies in an era of ultra-deep imaging
• Using H-alpha Morphology and Surface Brightness Fluctuations to Age-Date Star Clusters in M83
• The CALYMHA survey: Ly$\alpha$ escape fraction and its dependence on galaxy properties at $z=2.23$
• The First Deep ACS Lyman alpha Images of Local Starburst Galaxies
• HST Images of a Galaxy Group at z=2.81, and the Sizes of Damped Lyman Alpha Galaxies
• The escape of Lyman photons from a young starburst: the case of Haro 11
• Lya escape from z~0.03 star-forming galaxies: the dominant role of outflows
• The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage
• HST/ACS Lyman alpha imaging of the nearby starburst ESO338-IG04
• O VI Emission Imaging of a Galaxy with the Hubble Space Telescope: a Warm Gas Halo Surrounding the Intense Starburst SDSS J115630.63+500822.1
• The Lyman alpha reference sample: IV. Morphology at low and high redshift
• Inclination Dependence of Lyman-Alpha Properties in a Turbulent Disk Galaxy
• The Lyman Alpha Reference Sample: III. Properties of the Neutral ISM from GBT and VLA Observations
• The VANDELS survey: the role of ISM and galaxy physical properties on the escape of Lyα emission in z $\sim$ 3.5 star-forming galaxies
• Continuum subtracting Lyman-alpha images: Low redshift studies using the Solar Blind Channel of HST/ACS
• Deciphering Lyman $\alpha$ blob 1 with deep MUSE observations
• Lyman Alpha Reference Sample: X. Predicting Lyman alpha output from starforming galaxies using multivariate regression
• VLT/MUSE view of the highly ionized outflow cones in the nearby starburst ESO338-IG04
• Multiwavelength analysis of the Lyman alpha emitting galaxy Haro 2: relation between the diffuse Lyman alpha and soft X-ray emissions
• The Lyman Alpha Reference Sample. VIII. Characterizing Lyman-Alpha Scattering in Nearby Galaxies
• Physical properties and evolutionary state of the Lyman alpha emitting starburst galaxy IRAS 08339+6517
• The Lyman Alpha Reference Sample IX: Revelations from deep surface photometry
• Extinction Correction Significantly Influences the Estimate of Ly$\alpha$ Escape Fraction

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• The physics of Lyman-alpha escape from disc-like galaxies
• The Lensed Lyman-Alpha MUSE Arcs Sample (LLAMAS) : I. Characterisation of extended Lyman-alpha haloes and spatial offsets
• Linking Mg II and [O II] spatial distribution to ionizing photon escape in confirmed LyC leakers and non-leakers
• The Lyman $\alpha$ Reference Sample XIV: Lyman $\alpha$ imaging of 45 low redshift star-forming galaxies and inferences on global emission
• The Lyman-alpha and Continuum Origins Survey II: the connection between the escape of ionizing radiation and Lyman-alpha halos in star-forming galaxies
• Unveiling the gravitationally unstable disc of a massive star-forming galaxy using NOEMA and MUSE
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