Radiative Transfer in Lyα Nebulae: I. Modeling a Continuous or Clumpy Spherical Halo with a Central Source

Abstract

To understand the mechanism behind high-$z$ Ly$\alpha$ nebulae, we simulate the scattering of Ly$\alpha$ in a $\mathrm{H}\mathrm{I}$ halo about a central Ly$\alpha$ source. For the first time, we consider both smooth and clumpy distributions of halo gas, as well as a range of outflow speeds, total $\mathrm{H}\mathrm{I}$ column densities, $\mathrm{H}\mathrm{I}$ spatial concentrations, and central source galaxies (e.g., with Ly$\alpha$ line widths corresponding to those typical of AGN or star-forming galaxies). We compute the spatial-frequency diffusion and the polarization of the Ly$\alpha$ photons scattered by atomic hydrogen. Our scattering-only model reproduces the typical size of Ly$\alpha$ nebulae ($\sim 100$kpc) at total column densities $N_{\mathrm{HI}}\ge 10^{20}\mathrm{c}{\mathrm{m}}^{-2}$ and predicts a range of positive, flat, and negative polarization radial gradients. We also find two general classes of Ly$\alpha$ nebula morphologies: with and without bright cores. Cores are seen when $N_{\mathrm{HI}}$ is low, i.e., when the central source is directly visible, and are associated with a polarization jump, a steep increase in the polarization radial profile just outside the halo center. Of all the parameters tested in our smooth or clumpy medium model, $N_{\mathrm{HI}}$ dominates the trends. The radial behaviors of the Ly$\alpha$ surface brightness, spectral line shape, and polarization in the clumpy model with covering factor $f_c\gtrsim 5$ approach those of the smooth model at the same $N_{\mathrm{HI}}$. A clumpy medium with high $N_{\mathrm{HI}}$ and low $f_c\lesssim 2$ generates Ly$\alpha$ features via scattering that the smooth model cannot: a bright core, symmetric line profile, and polarization jump.

arXiv comment42 pages, 27 figures, accepted for publication in ApJ, Comments welcome!

References in corpus (49)

• Lyman Alpha Imaging of a Proto-Cluster Region at <z>=3.09
• The Subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of Lya Emitters from z=3.1 to 5.7 in the 1 deg^2 Field: Luminosity Functions and AGN
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• Ly Alpha-Emitting Galaxies at z=3.1: L* Progenitors Experiencing Rapid Star Formation
• Lyman Alpha Radiation From Collapsing Protogalaxies I: Characteristics of the Emergent Spectrum
• A Subaru Search for Ly-alpha Blobs in and around the Proto-cluster Region at Redshift z=3.1
• Ubiquitous giant Ly $\alpha$ nebulae around the brightest quasars at $z\sim 3.5$ revealed with MUSE
• Quasar Quartet Embedded in Giant Nebula Reveals Rare Massive Structure in Distant Universe
• Lyman Alpha Radiative Transfer in a Multi-Phase Medium
• Systematic Identification of LAEs for Visible Exploration and Reionization Research Using Subaru HSC (SILVERRUSH). I. Program Strategy and Clustering Properties of ~2,000 Lya Emitters at z=6-7 over the 0.3-0.5 Gpc${}^2$ Survey Area
• Monte Carlo Simulation of Lyman Alpha Scattering and Application to Damped Lyman Alpha Systems
• QSO MUSEUM I: A sample of 61 extended Ly$\alpha$-emission nebulae surrounding $z\sim 3$ quasars
• Discovery of an Enormous Ly$\alpha$ nebula in a massive galaxy overdensity at $z=2.3$
• Discovery of a Large ~200 kpc Gaseous Nebula at z=2.7 with the Spitzer Space Telescope
• Line Transfer through Clumpy, Large-Scale Outflows: Lyman Alpha Absorption and Halos around Starforming Galaxies
• Lyman Alpha Radiation From Collapsing Protogalaxies II: Observational Evidence for Gas Infall
• Extended Lyman Alpha Nebulae at z ~ 2.3: An Extremely Rare and Strongly Clustered Population?
• Evidence for Large-Scale Structure at z=2.4 From Lyman-alpha Imaging
• Quasars Probing Quasars IV: Joint Constraints on the Circumgalactic Medium from Absorption and Emission
• The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23
• Central Powering of the Largest Lyman-alpha Nebula is Revealed by Polarized Radiation
• Lyman-alpha line and continuum radiative transfer in a clumpy interstellar medium
• P-Cygni Type Lya from Starburst Galaxies
• Three Lyman-alpha emitting filaments converging to a massive galaxy group at z=2.91: discussing the case for cold gas infall
• Strong Field-to-Field Variation of Lyman alpha Nebulae Populations at z~2.3
• Deep HeII and CIV Spectroscopy of a Giant Lyman alpha Nebula: Dense Compact Gas Clumps in the Circumgalactic Medium of a z~2 Quasar
• Lyman alpha line formation in starbursting galaxies II. Extremely Thick, Dustless, and Static HI Media
• VIMOS-VLT spectroscopy of the giant Ly-alpha nebulae associated with three z~2.5 radio galaxies
• From Mirrors to Windows: Lyman-Alpha Radiative Transfer in a Very Clumpy Medium
• The Discovery of a Large Lyman-alpha+HeII Nebula at z~1.67: A Candidate Low Metallicity Region?
• The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies
• Resonant line transfer in a fog: Using Lyman-alpha to probe tiny structures in atomic gas
• Lyman-alpha blobs: polarization arising from cold accretion
• Discovery of a Proto-cluster Associated with a Ly-$\alpha$ Blob Pair at z=2.3
• The Properties of Lyman Alpha Nebulae: Gas Kinematics from Non-resonant Lines
• Kinematics of Gas in Lyman Alpha Nebulae
• ALMA observations of Lyman-alpha Blob 1: halo sub-structure illuminated from within
• Ly-alpha Radiative Transfer: Monte-Carlo Simulation of the Wouthuysen-Field Effect
• Polarization of the \lya Halos Around Sources Before Cosmological Reionization
• Revisiting the Gas Kinematics in SSA22 Lyman-$\alpha$ Blob 1 with Radiative Transfer Modeling in a Multiphase, Clumpy Medium
• Unlocking the Full Potential of Extragalactic Ly$\alpha$ through Its Polarization Properties
• Pinpointing the Molecular Gas within a Lyman Alpha Blob at z ~ 2.7
• What Makes Ly$\alpha$ Nebulae Glow? Mapping the Polarization of LABd05
• ALMA Observations of Lyman-alpha Blob 1: Multiple major-mergers and widely distributed interstellar media
• Ly-alpha Radiative Transfer: A Stokes Vector Approach to Ly-alpha Polarization
• Mapping the Polarization of the Radio-Loud Ly$\alpha$ Nebula B3 J2330+3927
• Polarization of Rayleigh scattered Lyα in active galactic nuclei
• Spatially resolved Lyman-$\alpha$ emission around radio bright quasars
• C IV and He II Line Emission of Lyman Alpha Blobs: Powered by Shock Heated Gas

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