On the effect of Lyman alpha trapping during the initial collapse of massive black hole seeds

Abstract

One viable seeding mechanism for supermassive black holes is the direct gaseous collapse route in pre-galactic dark matter halos, producing objects on the order of $10^4-10^6$ solar masses. These events occur when the gas is prevented from cooling below $10^4$ K that requires a metal-free and relatively H${}_2$-free medium. The initial collapse cools through atomic hydrogen transitions, but the gas becomes optically thick to the cooling radiation at high densities. We explore the effects ofLyman-$\alpha$ trapping in such a collapsing system with a suite of Monte Carlo radiation transport calculations in uniform density and isotropic cases that are based from a cosmological simulation. Our method includes both non-coherent scattering and two-photon line cooling. We find that Lyman-$\alpha$ radiation is marginally trapped in the parsec-scale gravitationally unstable central cloud, allowing the temperature to increase to 50,000 K at a number density of $3\times 10^4$ cm${}^{-3}$ and increasing the Jeans mass by a factor of five. The effective equation of state changes from isothermal at low densities to have an adiabatic index of 4/3 around the temperature maximum and then slowly retreats back to isothermal at higher densities. Our results suggest that Lyman-$\alpha$ trapping delays the initial collapse by raising the Jeans mass. Afterward the high density core cools back to $10^4$ K that is surrounded by a warm envelope whose inward pressure may alter the fragmentation scales at high densities.

15 pages, 8 figures, 3 tables, submitted to MNRAS

References in corpus (21)

• A luminous quasar at a redshift of z = 7.085
• Formation of Supermassive Black Holes by Direct Collapse in Pregalactic Halos
• An ultra-luminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30
• 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies
• The evolution of massive black hole seeds
• Accretion onto the First Stellar Mass Black Holes
• Uncertainties in H2 and HD Chemistry and Cooling and their Role in Early Structure Formation
• Fluctuations in the High-Redshift Lyman-Werner Background: Close Halo Pairs as the Origin of Supermassive Black Holes
• Resolving the Formation of Protogalaxies. II. Central Gravitational Collapse
• Quasars at z=6: the survival of the fittest
• Rapid growth of seed black holes in the early universe by supra-exponential accretion
• The aftermath of the first stars: massive black holes
• Resolving the Formation of Protogalaxies. I. Virialization
• Formation of massive protostars in atomic cooling haloes
• Direct collapse black hole formation from synchronized pairs of atomic cooling halos
• Gone With the Wind: Where is the Missing Stellar Wind Energy from Massive Star Clusters?
• The formation of compact massive self-gravitating discs in metal-free haloes with virial temperatures of ~ 13000-30000 K
• Lyman alpha Radiative Transfer in Cosmological Simulations using Adaptive Mesh Refinement
• The Lyman-alpha signature of the first galaxies
• Revised rate coefficients for H${}_2$ and H${}^{-}$ destruction by realistic stellar spectra
• Effects of turbulence and rotation on protostar formation as a precursor to seed black holes

Cited by in corpus (8)

• Direct collapse to supermassive black hole seeds: the critical conditions for suppression of ${\mathrm{H}}_2$ cooling
• Finding Direct-Collapse Black Holes at Birth
• Modelling the cosmological Lyman-Werner background radiation field in the Early Universe
• Lyman-$\alpha$ feedback prevails at Cosmic Dawn: Implications for the first galaxies, stars, and star clusters
• Resonant-line radiative transfer within power-law density profiles
• Lyman-alpha resonant-line radiative transfer in expanding media
• Photoevaporation from Inner Protoplanetary Disks Confronted with Observations
• Direct Collapse Pre-supermassive Black Hole Objects as Ly$\alpha$ Emitters