Heating the IGM by X-rays from Population III Binaries in High Redshift Galaxies

Abstract

Due to their long mean free path, X-rays are expected to have an important impact on cosmic reionization by heating and ionizing the IGM on large scales, especially after simulations have suggested that Population III stars may form in pairs at redshifts as high as 20 - 30. We use the Pop III distribution and evolution from a self-consistent cosmological radiation hydrodynamics simulation of the formation of the first galaxies and a simple Pop III X-ray binaries model to estimate their X-ray output in a high density region larger than 100 comoving (Mpc)${}^3$. We then combine three different methods --- ray tracing, a one-zone model, and X-ray background modeling --- to investigate the X-ray propagation, intensity distribution, and long term effects on the IGM thermal and ionization state. The efficiency and morphology of photo-heating and photo-ionization are dependent on the photon energies. The sub-keV X-rays only impact the IGM near the sources while the keV photons contribute significantly to the X-ray background and heat and ionize the IGM smoothly. The X-rays just below 1 keV are most efficient in heating and ionizing the IGM. We find that the IGM might be heated to over 100 K by $z=10$ and the high density source region might reach 10${}^4$ K, limited by atomic hydrogen cooling. This may be important for predicting the 21-cm neutral hydrogen signals. But, on the other hand, the free electrons from X-ray ionizations are not enough to contribute significantly to the optical depth of CMB to the Thomson scattering.

19 pages, 14 figures. Replaced to match published version

References in corpus (21)

• An Observational Determination of the Bolometric Quasar Luminosity Function
• Observational constraints on Cosmic Reionization
• The Formation of Population III Binaries from Cosmological Initial Conditions
• Fragmentation of star-forming clouds enriched with the first dust
• The Luminosity Function of X-ray Selected Active Galactic Nuclei: Evolution of Supermassive Black Holes at High Redshift
• The Global 21 Centimeter Background from High Redshifts
• Accretion onto the First Stellar Mass Black Holes
• 21 cm fluctuations from inhomogeneous X-ray heating before reionization
• Resolving the Formation of Protogalaxies. III. Feedback from the First Stars
• Population III stars: hidden or disappeared ?
• Population III star formation in a Lambda CDM universe, I: The effect of formation redshift and environment on protostellar accretion rate
• Population III star formation in a Lambda CDM universe, II: Effects of a photodissociating background
• The Destruction of Cosmological Minihalos by Primordial Supernovae
• The Birth of a Galaxy. II. The Role of Radiation Pressure
• Suppression of H_2 Cooling in the Ultraviolet Background
• Uncovering the Chemical Signature of the First Stars in the Universe
• Metal-Free Gas Supply at the Edge of Reionization: Late-Epoch Population III Star Formation
• Was Star-Formation Suppressed in High-Redshift Minihalos?
• How the First Stars Regulated Local Star Formation I: Radiative Feedback
• The Fate of the First Galaxies. III. Properties of Primordial Dwarf Galaxies and their Impact on the Intergalactic Medium
• Primordial Globular Clusters, X-Ray Binaries & Cosmological Reionisation

Cited by in corpus (16)

• Formation of massive black holes in rapidly growing pre-galactic gas clouds
• Recovery from population III supernova explosions and the onset of second generation star formation
• An Introductory Review on Cosmic Reionization
• Dynamical evolution of Population III stellar systems and the resulting binary statistics
• Scaling Relations for Galaxies Prior to Reionization
• X-ray Twinkles and Pop III Stars
• Spatially Extended 21 cm Signal from Strongly Clustered UV and X-Ray Sources in the Early Universe
• X-ray Background at High Redshifts from Pop III Remnants: Results from Pop III star formation rates in the Renaissance Simulations
• Exploring the cosmic dawn and epoch of reionization with 21cm line
• Microquasars as heating sources of the intergalactic medium during reionisation of the Universe
• Cosmological Impact of Population III Binaries
• First Light II: Emission Line Extinction, Population III Stars, and X-ray Binaries
• Some First Stars Were Red: Detecting Signatures of Massive Population III Formation Through Long-Term Stochastic Color Variations
• Coronal Properties of Low-mass Population III Stars and the Radiative Feedback in the Early Universe
• Population III Star Formation in an X-ray background: II. Protostellar Discs, Multiplicity and Mass Function of the Stars
• Exploring delaying and heating effects on the 21-cm signature of fuzzy dark matter