Probing the Intergalactic Medium with Ly α and 21 cm Fluctuations

Journal Article · Tue Oct 10 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA8EED· OSTI ID:22679768

Heneka, Caroline ^[1]; Cooray, Asantha; Feng, Chang ^[2]

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1. Dark Cosmology Center, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)
2. Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)

We study 21 cm and Ly α fluctuations, as well as H α , while distinguishing between Ly α emission of galactic, diffuse, and scattered intergalactic medium (IGM) origin. Cross-correlation information about the state of the IGM is obtained, testing neutral versus ionized medium cases with different tracers in a seminumerical simulation setup. In order to pave the way toward constraints on reionization history and modeling beyond power spectrum information, we explore parameter dependencies of the cross-power signal between 21 cm and Ly α , which displays a characteristic morphology and a turnover from negative to positive correlation at scales of a couple Mpc{sup −1}. In a proof of concept for the extraction of further information on the state of the IGM using different tracers, we demonstrate the use of the 21 cm and H α cross-correlation signal to determine the relative strength of galactic and IGM emission in Ly α . We conclude by showing the detectability of the 21 cm and Ly α cross-correlation signal over more than one decade in scale at high signal-to-noise ratio for upcoming probes like SKA and the proposed all-sky intensity mapping satellites SPHEREx and CDIM, while also including the Ly α damping tail and 21 cm foreground avoidance in the modeling.

• OSTI ID: 22679768
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 848; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AVOIDANCE
CORRELATIONS
COSMOLOGY
DAMPING
EMISSION
EXTRACTION
FLUCTUATIONS
HYDROGEN
INTERGALACTIC SPACE
LYMAN LINES
SATELLITES
SIGNAL-TO-NOISE RATIO
SIMULATION
SPECTRA
STARS
UNIVERSE