The Ooty Wide Field Array

Subrahmanya, C. R.; Manoharan, P. K.; Chengalur, Jayaram N.

doi:10.1007/s12036-017-9430-4

Cited by 34 publications

(26 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their primary goal is to measure the comoving scale of BAO around c 0000 The Authors the onset of acceleration at z ∼ 1. Efforts are also underway to observe the 21-cm intensity fluctuations around z ∼ 3.35 using OWFA (Subrahmanya et al 2017). On the other hand, the upgraded GMRT (uGMRT;Gupta 2017) and the upcoming SKA2 promises to cover a large redshift range.…”

Section: Introductionmentioning

confidence: 99%

Modelling redshift space distortion in the post-reionization H i 21-cm power spectrum

Sarkar

Bharadwaj

2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The post-reionization HI 21-cm signal is an excellent candidate for precision cosmology, this however requires accurate modelling of the expected signal. Sarkar et al. (2016) have simulated the real space HI 21-cm signal, and have modelled the HI power spectrum as P HI (k) = b 2 P (k) where P (k) is the dark matter power spectrum and b(k) is a (possibly complex) scale dependent bias for which fitting formulas have been provided. This paper extends these simulations to incorporate redshift space distortion and predict the expected redshift space HI 21-cm power spectrum P s HI (k ⊥ , k ) using two different prescriptions for the HI distributions and peculiar velocities. We model P s HI (k ⊥ , k ) assuming that it is the product of P HI (k) = b 2 P (k) with a Kaiser enhancement term and a Finger of God (FoG) damping which has σ p the pair velocity dispersion as a free parameter. Considering several possibilities for the bias and the damping profile, we find that the models with a scale dependent bias and a Lorentzian damping profile best fit the simulated P

show abstract

Section: Introductionmentioning

confidence: 99%

Modelling redshift space distortion in the post-reionization H i 21-cm power spectrum

Sarkar

Bharadwaj

2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Similarly CHIME is an experiment for detecting post-reionization distribution of HI at large scales. The Ooty Wide Field Array (OWFA) (Bargur et al, 2011;Subrahmanya, Manoharan and Chengalur, 2017) is the upgraded Ooty radio telescope where the collecting area and the primary receivers remain the same but the entire backend has been changed. OWFA has a much larger field of view and a much larger bandwidth as compared to the earlier configuration.…”

Section: Methodsologymentioning

confidence: 99%

Prospects of Detecting HI using Redshifted 21-cm Radiation at z∼3

Gehlot

Bagla

2017

J Astrophys Astron

View full text Add to dashboard Cite

Distribution of cold gas in the post-reionization era provides an important link between distribution of galaxies and the process of star formation. Redshifted 21 cm radiation from the Hyperfine transition of neutral Hydrogen allows us to probe the neutral component of cold gas, most of which is to be found in the interstellar medium of galaxies. Existing and upcoming radio telescopes can probe the large scale distribution of neutral Hydrogen via HI intensity mapping. In this paper we use an estimate of the HI power spectrum derived using an ansatz to compute the expected signal from the large scale HI distribution at z ∼ 3. We find that the scale dependence of bias at small scales makes a significant difference to the expected signal even at large angular scales. We compare the predicted signal strength with the sensitivity of radio telescopes that can observe such radiation and calculate the observation time required for detecting neutral Hydrogen at these redshifts. We find that OWFA (Ooty Wide Field Array) offers the best possibility to detect neutral Hydrogen at z ∼ 3 before the SKA (Square Kilometer Array) becomes operational. We find that the OWFA should be able to make a 3 σ or a more significant detection in 2000 hours of observations at several angular scales. Calculations done using the Fisher matrix approach indicate that a 5σ detection of the binned HI power spectrum via measurement of the amplitude of the HI power spectrum is possible in 1000 hours (Sarkar, Bharadwaj and Ali, 2017).

show abstract

“…Efforts are currently underway to upgrade the Ooty Radio Telescope (ORT) into a linear radio-interferometric array (Prasad & Subrahmanya 2011a,b;Subrahmanya et al 2017b;Subrahmanya et al 2017a), the Ooty Wide Field Array (OWFA). With a nominal frequency of ν0 = 326.5 MHz, this directly corresponds to measuring the H i radiation from the redshift z = 3.35.…”

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.…”

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

View full text Add to dashboard Cite

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.

show abstract

The Ooty Wide Field Array

Cited by 34 publications

References 31 publications

Modelling redshift space distortion in the post-reionization H i 21-cm power spectrum

Modelling redshift space distortion in the post-reionization H i 21-cm power spectrum

Prospects of Detecting HI using Redshifted 21-cm Radiation at z∼3

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

Contact Info

Product

Resources

About