Simulating the z = 3.35 HI 21-cm Visibility Signal for the Ooty Wide Field Array (OWFA)

Chatterjee, Suman; Bharadwaj, Somnath; Marthi, V. R.

doi:10.1007/s12036-017-9433-1

Cited by 7 publications

(6 citation statements)

References 48 publications

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“…The possibility of detecting the HI 21-cm signal using OWFA has been studied extensively [29,[73][74][75][76]. Detailed foreground predictions [29,77] and calibration issues [70] for OWFA have also been addressed.…”

Section: Predictions For the Ooty Wide Field Array (Owfa)mentioning

confidence: 99%

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

Sarkar¹,

Pal²,

Sarkar³

2019

J. Cosmol. Astropart. Phys.

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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.

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Section: Predictions For the Ooty Wide Field Array (Owfa)mentioning

confidence: 99%

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

Sarkar¹,

Pal²,

Sarkar³

2019

J. Cosmol. Astropart. Phys.

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“…These calculations include the HI signal, based on simulations of the expected cosmological distribution of HI. The HI simulations themselves are presented in Chatterjee et al (2017). More details regarding the predicted outcomes of observations of HI with OWFA can be found in Ali and Bharadwaj (2014); Bharadwaj et al (2015), as well as in Sarkar et al (2017).…”

Section: Hi At Z 33mentioning

confidence: 99%

The Ooty Wide Field Array

Subrahmanya¹,

Manoharan²,

Chengalur³

2017

J Astrophys Astron

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Abstract.We describe here an ongoing upgrade to the legacy Ooty Radio Telescope (ORT). The ORT is a cylindrical parabolic cylinder 530mx30m in size operating at a frequency of 326.5 (or z ∼ 3.35 for the HI 21cm line). The telescope has been constructed on a north-south hill slope whose gradient is equal to the latitude of the hill, making it effectively equitorially mounted. The feed consists of an array of 1056 dipoles. The key feature of this upgrade is the digitisation and cross-correlation of the signals of every set of 4-dipoles. This converts the ORT into a 264 element interferometer with a field of view of 2 • × 27.4 • cos(δ). This upgraded instrument is called the Ooty Wide Field Array (OWFA). This paper briefly describes the salient features of the upgrade, as well as its main science drivers. There are three main science drivers viz.(1) Observations of the large scale distribution of HI in the post-reionisation era (2) studies of the propagation of plasma irregularities through the inner heliosphere and (3) blind surveys for transient sources. More details on the upgrade, as well as on the expected science uses can be found in other papers in this special issue.

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“…Simulated foreground predictions for OWFA are presented in Marthi et al (2017) where, in addition, they present a detailed analysis of the instrument-induced systematics and discuss the multi-frequency angular power spectrum estimator (MAPS) for OWFA. Chatterjee et al (2017) present simulations of the H i 21-cm visibility signal expected for OWFA.…”

Section: Introductionmentioning

confidence: 99%

An analytical method to simulate the H i 21-cm visibility signal for intensity mapping experiments

Sarkar

Bharadwaj

Marthi

2017

Monthly Notices of the Royal Astronomical Society

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Simulations play a vital role in testing and validating H i 21-cm power spectrum estimation techniques. Conventional methods use techniques like N-body simulations to simulate the sky signal which is then passed through a model of the instrument. This makes it necessary to simulate the H i distribution in a large cosmological volume, and incorporate both the light-cone effect and the telescope's chromatic response. The computational requirements may be particularly large if one wishes to simulate many realizations of the signal. In this paper we present an analytical method to simulate the H i visibility signal. This is particularly efficient if one wishes to simulate a large number of realizations of the signal. Our method is based on theoretical predictions of the visibility correlation which incorporate both the light-cone effect and the telescope's chromatic response. We have demonstrated this method by applying it to simulate the H i visibility signal for the upcoming Ooty Wide Field Array Phase I.

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Simulating the z = 3.35 HI 21-cm Visibility Signal for the Ooty Wide Field Array (OWFA)

Abstract: explore the relation between the expected visibility correlations and the underlying HI power spectrum.

Cited by 7 publications

References 48 publications

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

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

The Ooty Wide Field Array

An analytical method to simulate the H i 21-cm visibility signal for intensity mapping experiments

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