Constraining warm dark matter power spectrum using the cross-correlation of HI 21 cm signal and the Lyman-α forest

Abstract

We have considered the prospects for measuring the cross Warm Dark Matter (WDM) power spectrum of the redshifted HI 21-cm signal and the Lyman-α forest and thereby constraining WDM mass using observations with upcoming radio-interferometers—the Ooty Wide Field Array (OWFA) and SKA1-mid, and a spectroscopic survey of the quasars. We have considered a quasar survey with a mean observed quasar number density of n̄Q = 48 deg−2 over a collecting area of 14455 deg2, and a mean spectroscopic SNR = 5. Our analysis with OWFA shows that it is possible to measure the WDM power spectrum in several k-bins at k ⩽ 0.45 Mpc−1 with SNR > 5 using observations of 200 hours each in 100 different fields-of-view for mWDM = 0.25 keV . Considering the possibility of the joint measurement of the parameters, the warm dark matter density parameter ΩWDM, and the dark energy density parameter ΩΛ0, we find that the relative error on the 1−σ measurement of the parameter ΩWDM is ∼ 0.8 for a fiducial mWDM = 0.25 keV . However, we find that OWFA is not sensitive towards measuring the suppression of the WDM power spectrum, and therefore, cannot be used to constrain the WDM mass. Considering the analysis with SKA I mid, we find that for a fiducial mWDM= 0.25 keV, the suppression in the cross power spectrum can be measured at ∼ 10 − σ around k ∼ 0.2 Mpc−1 for a total observing time of 20000 hours distributed uniformly over 50 independent pointings where we have binned the available k-range as Δ k = k/5.

Probing Quintessence using BAO imprint on the cross-correlation of weak lensing and post-reionization HI 21 cm signal

“…We have assumed that this key challenge is addressed. Even after significant foreground removal, the cosmological origin of the 21 cm signal can only be ascertained only through a cross-correlation (Guha Sarkar et al 2010;Carucci et al 2017;Sarkar et al 2019). The foregrounds for the two individual probes are expected to be significantly uncorrelated and hence leads to negligible effects in the observing cross-correlation power spectrum.…”

“…Further, the foregrounds and contaminants of individual surveys are, in most cases, uncorrelated and hence do not bias the cross-correlation signal (Sarkar 2010;Vallinotto et al 2009). The cross-correlation of the post-reionization HI 21 cm signal has been extensively studied (Sarkar et al 2009;Guha Sarkar et al 2010;Sarkar 2010;Sarkar et al 2019;Dash & Guha Sarkar 2021).…”

Constraining dark energy using the cross correlations of weak lensing with post-reionization probes of neutral hydrogen

“…Large scale numerical simulations indicate that on large cosmological scales both the Lyman-α forest and the 21-cm signal are biased tracers of the underlying dark matter (DM) distribution [69][70][71][72][73]. This has allowed the possibility of studying cross-correlations between Lyman-α and post reionization 21-cm signal [66,72,[74][75][76]. We consider the cross correlation JCAP02(2021)016 of these post-reionization tracers with the weak-lensing convergence field to constrain dark energy models.…”

Constraining dark energy using the cross correlations of weak lensing with post-reionization probes of neutral hydrogen

“…Large scale numerical simulations indicate that on large cosmological scales both the Lyman-α forest and the 21-cm signal are biased tracers of the underlying dark matter (DM) distribution [69][70][71][72]. This has allowed the possibility of studying cross-correlations between Lyman-α and post reionization 21-cm signal [66,[72][73][74][75]. We consider the cross correlation of these post-reionization tracers with the weak-lensing convergence field to constrain dark energy models.…”