The cross-correlation between the 21 cm field and the galaxy distribution is a potential probe of the Epoch of Reionization (EoR). The 21 cm signal traces neutral gas in the intergalactic medium and, on large spatial scales, this should be anticorrelated with the high-redshift galaxy distribution, which partly sources and tracks the ionized gas. In the near future, interferometers such as the Hydrogen Epoch of Reionization Array (HERA) are projected to provide extremely sensitive measurements of the 21 cm power spectrum. At the same time, the Nancy Grace Roman Space Telescope (Roman) will produce the most extensive catalog to date of bright galaxies from the EoR. Using seminumeric simulations of reionization, we explore the prospects for measuring the cross-power spectrum between the 21 cm and galaxy fields during the EoR. We forecast a 12
Line-intensity mapping (IM) experiments seek to perform statistical measurements of large-scale structure with spectral lines such as 21 cm, CO, and Ly
- NSF-PAR ID:
- 10468378
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 956
- Issue:
- 2
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 84
- Size(s):
- ["Article No. 84"]
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract σ detection between HERA and Roman, assuming an overlapping survey area of 500 deg2, redshift uncertainties ofσ z = 0.01 (as expected for the high-latitude spectroscopic survey of Lyα -emitting galaxies), and an effective Lyα emitter duty cycle off LAE= 0.1. Thus the HERA–Roman cross-power spectrum may be used to help verify 21 cm detections from HERA. We find that the shot-noise in the galaxy distribution is a limiting factor for detection, and so supplemental observations using Roman should prioritize deeper observations, rather than covering a wider field of view. We have made a public GitHub repository containing key parts of the calculation, which accompanies this paper:https://github.com/plaplant/21cm_gal_cross_correlation. -
more » « less
Abstract We report the discovery of an accreting supermassive black hole at
z = 8.679. This galaxy, denoted here as CEERS_1019, was previously discovered as a Lyα -break galaxy by Hubble with a Lyα redshift from Keck. As part of the Cosmic Evolution Early Release Science (CEERS) survey, we have observed this source with JWST/NIRSpec, MIRI, NIRCam, and NIRCam/WFSS and uncovered a plethora of emission lines. The Hβ line is best fit by a narrow plus a broad component, where the latter is measured at 2.5σ with an FWHM ∼1200 km s−1. We conclude this originates in the broadline region of an active galactic nucleus (AGN). This is supported by the presence of weak high-ionization lines (N V, N IV], and C III]), as well as a spatial point-source component. The implied mass of the black hole (BH) is log (M BH/M ⊙) = 6.95 ± 0.37, and we estimate that it is accreting at 1.2 ± 0.5 times the Eddington limit. The 1–8μ m photometric spectral energy distribution shows a continuum dominated by starlight and constrains the host galaxy to be massive (log M/M⊙∼9.5) and highly star-forming (star formation rate, or SFR ∼ 30 M⊙yr−1; log sSFR ∼ − 7.9 yr−1). The line ratios show that the gas is metal-poor (Z /Z ⊙∼ 0.1), dense (n e ∼ 103cm−3), and highly ionized (logU ∼ − 2.1). We use this present highest-redshift AGN discovery to place constraints on BH seeding models and find that a combination of either super-Eddington accretion from stellar seeds or Eddington accretion from very massive BH seeds is required to form this object. -
more » « less
Abstract An unprecedented array of new observational capabilities are starting to yield key constraints on models of the epoch of first light in the Universe. In this Letter we discuss the implications of the UV radiation background at cosmic dawn inferred by recent JWST observations for radio experiments aimed at detecting the redshifted 21 cm hyperfine transition of diffuse neutral hydrogen. Under the basic assumption that the 21 cm signal is activated by the Ly
α photon field produced by metal-poor stellar systems, we show that a detection at the low frequencies of the EDGES and SARAS3 experiments may be expected from a simple extrapolation of the declining UV luminosity density inferred atz ≲ 14 from JWST early galaxy data. Accounting for an early radiation excess above the cosmic microwave background suggests a shallower or flat evolution to simultaneously reproduce low- and high-z current UV luminosity density constraints, which cannot be entirely ruled out, given the large uncertainties from cosmic variance and the faint-end slope of the galaxy luminosity function at cosmic dawn. Our findings raise the intriguing possibility that a high star formation efficiency at early times may trigger the onset of intense Lyα emission at redshiftz ≲ 20 and produce a cosmic 21 cm absorption signal 200 Myr after the Big Bang. -
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
-
more » « less
ABSTRACT We forecast the prospects for cross-correlating future line intensity mapping (LIM) surveys with the current and future Ly-α forest measurements. Using large cosmological hydrodynamic simulations, we model the emission from the CO rotational transition in the CO Mapping Array Project LIM experiment at the 5-yr benchmark and the Ly-α forest absorption signal for extended Baryon Acoustic Oscillations (BOSS), Dark energy survey instrument (DESI), and Prime Focus multiplex Spectroscopy survey (PFS). We show that CO × Ly-α forest significantly enhances the detection signal-to-noise ratio (S/N) of CO, with up to $300{{\ \rm per\, cent}}$ improvement when correlated with the PFS Ly-α forest survey and a 50–75 per cent enhancement with the available eBOSS or the upcoming DESI observations. This is competitive with even CO × spectroscopic galaxy surveys. Furthermore, our study suggests that the clustering of CO emission is tightly constrained by CO × Ly-α forest due to the increased sensitivity and the simplicity of Ly-α absorption modelling. Foreground contamination or systematics are expected not to be shared between LIM and Ly-α forest observations, providing an unbiased inference. Ly-α forest will aid in detecting the first LIM signals. We also estimate that [C ii] × Ly-α forest measurements from Experiment for Cryogenic Large-Aperture Intensity Mapping and DESI/eBOSS should have a larger S/N than planned [C ii] × quasar observations by about an order of magnitude.
