Mapping Neutral Hydrogen during Reionization with the Lyα Emission from Quasar Ionization Fronts

By S. Cantalupo, C. Porciani, S. Lilly. 2007

239 citations recorded by the source corpus.

We present a new method to directly map the neutral-hydrogen distribution during the reionization epoch and constrain the emission properties of the highest redshift quasars (QSOs). As a tracer of H I, we propose to use the Lyα radiation produced by quasar ionization fronts (I-fronts) that expand in the partially ionized intergalactic medium (IGM) before reionization is complete. These Lyα photons are mainly generated by H I collisional excitations. Combining two radiative transfer models (one for the QSO ionizing radiation and one for the Lyα photons), we estimate the expected Lyα spectral shape and surface brightness (SBLyα) for a large number of configurations where we varied both the properties of the ionizing QSO and of the surrounding medium. We find that the expected signal is observable as a single (broad) emission line with a characteristic width of 100-200 km s−1. The expected SBLyα produced at redshift z ≳ 6.5 within a fully neutral region (at mean density) by a typical QSO I-front lies in the range 10−21 to 10−20 ergs s−1 cm−2 arcsec−2 and decreases proportionally to (1 + z)2 for a given QSO age. QSOs with harder spectra may produce a significantly brighter emission at early phases. The signal may cover up to a few hundred square arcminutes on the sky and should be already detectable with current facilities by means of moderate- to high-resolution spectroscopy. The detection of this Lyα emission can shed new light on the reionization history, the age and the emission properties of the highest redshift QSOs.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/00323ab9a0e39fb2a5c9433affb87813f80369e9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

The Astrophysics of Ultrahigh-Energy Cosmic Rays (2011, background): “For instance, the properties of UHECR transport in a strongly magnetized local supercluster or in clusters of galaxies have been discussed (e.g., Berezinsky et al. 1990a, 1997; Blasi & Olinto 1999; Lemoine et al. 1999; Ide et al. 2001; Medina Tanco 2001, and see Section 6.3 for more references on…”
Cosmic-Ray Protons Accelerated at Cosmological Shocks and Their Impact on Groups and Clusters of Galaxies (2001, background): “There are additional sources of CRs in clusters, of course, such as active galaxies (Ensslin et al. 1997 ; Berezinsky et al. 1997).”
Cool outflows in galaxies and their implications (2020, background): “26 4 cm3 s−1 is the effective Case B Lyα recombination coefficient (Cantalupo et al. 2008), and Ce ≡ 〈n(2)e〉/〈ne〉(2) is the electron density clumping factor, which can be assumed to be of order unity on a cloud-by-cloud basis (i.”
THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION (2009, background): “Since galaxy clusters can store cosmic rays (Berezinsky et al. 1997) injected either by AGNs or accelerated by primordial shocks,γ-rays can be produced in pp interactions via production and decay of neutral pions and from annihilating DM or supersymmetrical particles.”
SEARCH FOR COSMIC-RAY-INDUCED GAMMA-RAY EMISSION IN GALAXY CLUSTERS (2013, background): “…I-00133 Roma, Italy 60 Department of Physics, University of California, Santa Barbara, CA 93106-9530, USA Völk et al. 1996; Enßlin et al. 1997; Berezinsky et al. 1997; Pfrommer & Enßlin 2004a) and significant populations of CR protons can accumulate due to their long cooling time in the…”
Simulating cosmic rays in clusters of galaxies – II. A unified scheme for radio haloes and relics with predictions of the γ-ray emission (2007, background): “…CRs with energies E < 2 × 107 GeV to clusters and yields to CR proton lifetimes of the order of the Hubble time (Völk et al. 1996; Ensslin et al.1997; Berezinsky et al. 1997; Colafrancesco & Blasi 1998), long enough to diffuse away from the production site and to maintain a spacefilling…”