The MUSE Extremely Deep Field: Classifying the Spectral Shapes of Lya Emitting Galaxies

Abstract

The Hydrogen Lyman-alpha (Lya) line shows a large variety of shapes which is caused by factors at different scales, from the interstellar medium to the intergalactic medium. This work aims to provide a systematic inventory and classification of the spectral shapes of Lya emission lines to understand the general population of high-redshift Lya emitting galaxies (LAEs). Using the data from the MUSE eXtremely Deep Field, we select 477 galaxies at z=2.8-6.6. We develop a method to classify Lya emission lines in four spectral and three spatial categories, by combining a spectral analysis with a narrow-band image analysis. We measure spectral properties, such as the peak separation and the blue-to-total flux ratio. To ensure a robust sample for statistical analysis, we define a final unbiased sample of 206 galaxies by applying thresholds for signal-to-noise ratio, peak separation, and Lya luminosity. Our analysis reveals that between 32% and 51% of the galaxies exhibit double-peaked profiles. This fraction seems to evolve dependently with the Lya luminosity, while we don't notice a severe decrease of this fraction with redshift. A large amount of these double-peaked profiles shows blue-dominated spectra, suggesting unique gas dynamics and inflow characteristics in some high-redshift galaxies. Among the double-peaked galaxies, 4% are spurious detections. Around 20% out of the 477 sources of the parent sample lie in a complex environment, meaning there are other clumps or galaxies at the same redshift within a distance of 30kpc. Our results suggest that the Lya double-peak fraction may trace the evolution of IGM attenuation, but faintest galaxies are needed to be observed at high redshift. In addition, it is crucial to obtain secure systemic redshifts for LAEs to better constrain the nature of the double-peaks.

arXiv comment36 pages, 29 figures, 9 tables, accepted for publication in A&A

References in corpus (64)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Rest-Frame Ultraviolet Spectra of z~3 Lyman Break Galaxies
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• The Cosmic Origins Spectrograph
• JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy
• The Data Processing Pipeline for the MUSE Instrument
• The MUSE Hubble Ultra Deep Field Survey: I. Survey description, data reduction and source detection
• Luminosity functions of Lyman-alpha emitters at z=6.5, and z=5.7: evidence against reionization at z=6
• Low-redshift Lyman continuum leaking galaxies with high [OIII]/[OII] ratios
• Lyman Alpha Radiation From Collapsing Protogalaxies I: Characteristics of the Emergent Spectrum
• Using Lyman-alpha to detect galaxies that leak Lyman continuum
• Ly$\alpha$ emission from Green Peas: the role of circumgalactic gas density, covering, and kinematics
• Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters
• Observations of the Lyman-$\alpha$ Universe
• Hubble imaging of the ionizing radiation from a star-forming galaxy at z=3.2 with fesc>50%
• Intergalactic Transmission and its Impact on the Lyα Line
• Direct Lyman continuum and Lyman-alpha escape observed at redshift 4
• UVUDF: Ultraviolet Through Near-infrared Catalog and Photometric Redshifts of Galaxies in the Hubble Ultra Deep Field
• The Ly-alpha Properties of Faint Galaxies at z2-3 with Systemic Redshifts and Velocity Dispersions from Keck-MOSFIRE
• The MUSE Hubble Ultra Deep Field Survey: II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies
• The Low-Redshift Lyman Continuum Survey I: New, Diverse Local Lyman-Continuum Emitters
• The Spectroscopic Properties of Lyα-Emitters at z $\approx$ 2.7: Escaping Gas and Photons from Faint Galaxies
• Lyman continuum leakage from low-mass galaxies with Mstar < 1.E8 Msun
• Gravitational lensing reveals ionizing ultraviolet photons escaping from a distant galaxy
• Recovering the systemic redshift of galaxies from their Lyman-alpha line profile
• The MUSE-Wide Survey: Survey Description and First Data Release
• The MUSE Hubble Ultra Deep Field surveys: Data release II
• The Kinematics of Multiple-Peaked Ly-alpha Emission in Star-Forming Galaxies at z~2-3
• Green Pea Galaxies Reveal Secrets of Ly$\alpha$ Escape
• A Close Comparison between Observed and Modeled Lyα Lines for z ~ 2.2 Lyman Alpha Emitters
• A Luminous Lyman-alpha Emitting Galaxy at Redshift z=6.535: Discovery and Spectroscopic Confirmation
• Lyman alpha emission in high-redshift galaxies
• The nature of luminous Lyman-alpha emitters at z~2-3: maximal dust-poor starbursts and highly ionising AGN
• Diverse properties of Ly-alpha emission in low-redshift compact star-forming galaxies with extremely high [OIII]/[OII] ratios
• Three Lyman-alpha emitting filaments converging to a massive galaxy group at z=2.91: discussing the case for cold gas infall
• Lya escape from z~0.03 star-forming galaxies: the dominant role of outflows
• Puzzling Lyman-alpha line profiles in green pea galaxies
• The X-SHOOTER Lyman-$\alpha$ survey at z=2 (XLS-z2) I: What makes a galaxy a Lyman-$\alpha$ emitter?
• The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage
• An Ultraluminous Lyman Alpha Emitter with a Blue Wing at z=6.6
• Star formation rates in Lyman break galaxies: radio stacking of LBGs in the COSMOS field and the sub-$\mu$Jy radio source population
• Three Lyman-alpha emitting galaxies within a quasar proximity zone at z=5.8
• Complex Lyman Alpha Profiles in Redshift 6.6 Ultraluminous Lyman Alpha Emitters
• An extreme blue nugget, UV-bright starburst at z=3.613 with ninety per cent of Lyman continuum photon escape
• Self-shielding Effects on the Column Density Distribution of Damped Lyman Alpha Systems
• Lyman-$\alpha$ as a tracer of cosmic reionisation in the SPHINX radiation-hydrodynamics cosmological simulation
• Illuminating gas in-/outflows in the MUSE deepest fields: discovery of Ly-alpha nebulae around forming galaxies at z~3.3
• Simulating the diversity of shapes of the Lyman-$\alpha$ line
• Spectral shapes of the Lyman-alpha emission from galaxies: I. blueshifted emission and intrinsic invariance with redshift
• Equivalent widths of Lyman $\alpha$ emitters in MUSE-Wide and MUSE-Deep
• MUSE Spectroscopic Identifications of Ultra-Faint Emission Line Galaxies with M${}_{\mathrm{UV}}\sim$ -15
• The HDUV Survey: Six Lyman Continuum Emitter Candidates at z~2 Revealed by HST UV Imaging
• Double-peaked Lyman-$\alpha$ emission at z=6.803: a reionisation-era galaxy self-ionising its local HII bubble
• The MUSE eXtremely Deep Field: Individual detections of Lyα haloes around rest-frame UV-selected galaxies at z~2.9-4.4
• ORIGIN: Blind detection of faint emission line galaxies in MUSE datacubes
• Where Outflows Meet Inflows: Gas Kinematics in SSA22 Lyman-$\alpha$ Blob 2 Decoded by Advanced Radiative Transfer Modelling
• A double-peaked Lyman-$\alpha$ emitter with a strong blue peak multiply imaged by the galaxy cluster RXC J0018.5+1626
• LESSER: A Catalogue of Spectroscopically selected sample of Lyman-$\alpha$ Emitters Lensed By Galaxies
• Deciphering stellar metallicities in the early Universe: Case study of a young galaxy at z = 4.77 in the MUSE eXtremely Deep Field
• Linking UV spectral properties of MUSE Ly-alpha emitters at z>3 to Lyman continuum escape

Cited by in corpus (1)

• A unique window into the Epoch of Reionisation: A double-peaked Lyman-$\alpha$ emitter in the proximity zone of a quasar at $z\sim 6.6$