Fisher Matrix Predictions for Detecting the Cosmological 21-cm Signal with the Ooty Wide Field Array (OWFA)

Bharadwaj, Somnath; Sarkar, Arnab; Ali, Sk Zeeshan

doi:10.1007/s12036-015-9346-9

Cited by 16 publications

(11 citation statements)

References 27 publications

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“…Longer integrations (∼ 1000 hrs (Sarkar et al, 2017;Ghelot and Bagla, 2017)), should have the sensitivity to measure the power spectrum at angular scales between 11 ′ and 3 o (or wavenumbers from ∼ 0.02 to 0.5 Mpc −1 ). Two important astro-physical parameters that are constrained by these observations are the amplitude of the power spectrum A HI (which in turn depends on the cosmic density of neutral hydrogen (Ω HI ), the neutral fraction (x HI ), and the bias parameter (b HI )) and the redshift distortion parameter β (Bharadwaj et al, 2015). As mentioned above, these measurements in turn also lead to constraints on the cosmological parameters (Bharadwaj et al, 2009).…”

Section: Hi At Z 33mentioning

confidence: 92%

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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Section: Hi At Z 33mentioning

confidence: 92%

The Ooty Wide Field Array

Subrahmanya¹,

Manoharan²,

Chengalur³

2017

J Astrophys Astron

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“…We choose the observational central frequency to be 710M Hz corresponding to this redshift. We first consider an OWFA [86][87][88] like array which is the upgraded version of the Ooty radio telescope and is expected to operate as an linear radio-interferometric array. The OWFA is a 530 m long and 30 m wide parabolic cylindrical reflector that is placed along the north-south direction on a hill that has the same slope (∼ 11 • ) as the latitude of the place.…”

Section: Cosmology With F (R) Gravitymentioning

confidence: 99%

Intensity mapping of post-reionization 21-cm signal and its cross-correlations as a probe of $f(R)$ gravity

Dash¹,

Sarkar²,

Sarkar³

2020

Preprint

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We propose the intensity mapping of the redshifted H i 21-cm signal from the post-reionization epoch as a cosmological probe of f (R) gravity. We consider the Hu-Sawicki family of f (R) gravity models characterized by a single parameter f,R0. The f (R) modification to gravity affects the postreionization 21-cm power spectrum through the change in the growth rate of density fluctuations. The quantity of interest is the redshift space distortion parameter βT (k, z) which imprints the change. We find that a radio interferometric observation at an observing frequency 710MHz with a SKA-1-Mid like radio telescope may measure the binned βT (k) at a level of sensitivity to distinguish f (R) models with log 10 |f,R0| > −5 at a > 5 − σ level in the k range k > 0.4M P c −1 . We find that using a Fisher matrix analysis the 68% bound obtained on the parameter is −5.62 < log 10 |f,R0| < −4.38 which is competitive with other probes of f (R) gravity. Thus the future observation of the post-reionization H i signal holds the potential to put robust constraints on f (R) gravity models and enrich our understanding of late time cosmic evolution and structure formation.

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“…The correlations between the adjacent baselines are approximately one-fourth of those between the same baselines (Bharadwaj et al 2015) There are 38 such blocks, each with 128 × 128 elements. The complex conjugate of these blocks also appears in S 2ab .…”

Section: The Ooty Wide Field Array (Owfa)mentioning

confidence: 99%

“…The primary science goals of OWFA have been outlined in Subrahmanya et al (2017b), and the measurement of the z = 3.35 post-reionization H i 21-cm power spectrum is one of its major objectives. It has been predicted (Bharadwaj et al 2015) that a 5σ detection of the amplitude of the H i 21-cm power spectrum is possible with ∼ 150 hrs of observation. Further, Sarkar et al (2017) predict that a ∼ 5σ measurement of the binned H i 21-cm power spectrum is possible in the k-range 0.05 k 0.3 Mpc −1 with 1, 000 hrs of observation.…”

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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Fisher Matrix Predictions for Detecting the Cosmological 21-cm Signal with the Ooty Wide Field Array (OWFA)

Cited by 16 publications

References 27 publications

The Ooty Wide Field Array

The Ooty Wide Field Array

Intensity mapping of post-reionization 21-cm signal and its cross-correlations as a probe of $f(R)$ gravity

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

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