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  • Probing the Diffuse Lyα Emission on Cosmological Scales: Lyα Emission Intensity Mapping Using the Complete SDSS-IV eBOSS
Title: Probing the Diffuse Lyα Emission on Cosmological Scales: Lyα Emission Intensity Mapping Using the Complete SDSS-IV eBOSS
Abstract Based on Sloan Digital Sky Survey Data Release 16, we have detected the large-scale structure of Ly α emission in the universe at redshifts z = 2–3.5 by cross-correlating quasar positions and Ly α emission imprinted in the residual spectra of luminous red galaxies. We apply an analytical model to fit the corresponding Ly α surface brightness profile and multipoles of the redshift-space quasar–Ly α emission cross-correlation function. The model suggests an average cosmic Ly α luminosity density of 6.6 − 3.1 + 3.3 × 10 40 erg s − 1 cMpc − 3 , a ∼2 σ detection with a median value about 8–9 times those estimated from deep narrowband surveys of Ly α emitters at similar redshifts. Although the low signal-to-noise ratio prevents us from a significant detection of the Ly α forest–Ly α emission cross-correlation, the measurement is consistent with the prediction of our best-fit model from quasar–Ly α emission cross-correlation within current uncertainties. We rule out the scenario where the Ly α photons mainly originate from quasars. We find that Ly α emission from star-forming galaxies, including contributions from that concentrated around the galaxy centers and that in diffuse Ly α -emitting halos, is able to explain the bulk of the Ly α luminosity density inferred from our measurements. Ongoing and future surveys can further improve the measurements and advance our understanding of the cosmic Ly α emission field.  more » « less
Award ID(s):
2007499
PAR ID:
10420271
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
The Astrophysical Journal Supplement Series
Volume:
262
Issue:
2
ISSN:
0067-0049
Page Range / eLocation ID:
38
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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