|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'506'133
Articles rated: 2609
26 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Conditions for Reionizing the Universe with A Low Galaxy Ionizing Photon Escape Fraction | | Steven L. Finkelstein
; Anson D'Aloisio
; Jan-Pieter Paardekooper
; Russell Ryan Jr.
; Peter Behroozi
; Kristian Finlator
; Rachael Livermore
; Phoebe R. Upton Sanderbeck
; Claudio Dalla Vecchia
; Sadegh Khochfar
; | | Date: |
7 Feb 2019 | | Abstract: | We explore scenarios for reionizing the intergalactic medium with low galaxy
ionizing photon escape fractions. We combine simulation-based halo-mass
dependent escape fractions with an extrapolation of the observed galaxy
rest-ultraviolet luminosity functions to solve for the reionization history
from z=20 to z=4. We explore the posterior distributions for key unknown
quantities, including the limiting halo mass for star-formation, the ionizing
photon production efficiency, and a potential contribution from active galactic
nuclei (AGN). We marginalize over the allowable parameter space using a Markov
Chain Monte Carlo method, finding a solution which satisfies the most
model-independent constraints on reionization. Our fiducial model can match
observational constraints with an average escape fraction of <5% throughout the
bulk of the epoch of reionization if: i) galaxies form stars down to the atomic
cooling limit before reionization and a photosuppression mass of
log(M_h/Msol)~9 during/after reionization (-13<M_UV,lim<-11); ii) galaxies
become more efficient producers of ionizing photons at higher redshifts and
fainter magnitudes, and iii) there is a significant, but sub-dominant,
contribution by AGN at z < 7. In this model the faintest galaxies (M_UV>-15)
dominate the ionizing emissivity, leading to an earlier start to reionization
and a smoother evolution of the ionized volume filling fraction than models
which assume a single escape fraction at all redshifts and luminosities. The
ionizing emissivity from this model is consistent with observations at z=4-5
(and below, when extrapolated), in contrast to some models which assume a
single escape fraction. Our predicted ionized volume filling fraction at z=7 of
Q_HII=78% (+- 8%) is in ~1-2 sigma tension with observations of Lya emitters
at z~7 and the damping wing analyses of the two known z>7 quasars, which prefer
Q_HII,z=7~40-50%. | | Source: | arXiv, 1902.2792 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER