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We derive optimal estimators for the two-, three-, and four-point correlators of statistically isotropic scalar fields defined on the sphere, such as the Cosmic Microwave Background temperature fluctuations, allowing for arbitrary (linear)…

宇宙学与河外天体物理 · 物理学 2023-06-28 Oliver H. E. Philcox

We report upper-limits on the Epoch of Reionization (EoR) 21 cm power spectrum at redshifts 7.9 and 10.4 with 18 nights of data ($\sim36$ hours of integration) from Phase I of the Hydrogen Epoch of Reionization Array (HERA). The Phase I…

Three peaks and two dips have been detected in the power spectrum of the cosmic microwave background from the BOOMERANG experiment, at $\ell \sim 210, 540, 840$ and $\ell \sim 420, 750$, respectively. Using model-independent analyses, we…

The emission from neutral hydrogen (HI) clouds in the post-reionization era (z < 6), too faint to be individually detected, is present as a diffuse background in all low frequency radio observations below 1420 MHz. The angular and frequency…

天体物理学 · 物理学 2009-10-29 Somnath Bharadwaj , Shiv K. Sethi , Tarun Deep Saini

21cm tomography promises to be a powerful tool for estimating cosmological parameters, constraining the epoch of reionization, and probing the so-called dark ages. However, realizing this promise will require the extraction of a…

宇宙学与河外天体物理 · 物理学 2011-06-02 Adrian Liu , Max Tegmark

COMPASS is a fixed-target experiment at the CERN SPS for the investigation of the structure and the dynamics of hadrons. The experimental setup features a large acceptance and high momentum resolution spectrometer including particle…

高能物理 - 实验 · 物理学 2019-08-13 A. Austregesilo

One of the most promising probes to complement current standard cosmological surveys is the HI intensity map, i.e. the distribution of temperature fluctuations in neutral hydrogen. In this paper we present calculations of the 2-point…

宇宙学与河外天体物理 · 物理学 2024-06-24 Anut Sangka , David Bacon

Redshifted 21cm-line signal from neutral hydrogens in the intergalactic medium (IGM) gives a direct probe of the epoch of reionization (EoR). In this paper, we investigate the potential of the variance and skewness of the probability…

宇宙学与河外天体物理 · 物理学 2018-08-31 Kenji Kubota , Shintaro Yoshiura , Hayato Shimabukuro , Keitaro Takahashi

Detecting neutral Hydrogen (H\,{\sc i}) via the 21~cm line emission from the intergalactic medium at $z\gtrsim 6$ has been identified as one of the most promising probes of the epoch of cosmic reionization -- a major phase transition of the…

宇宙学与河外天体物理 · 物理学 2018-07-04 Nithyanandan Thyagarajan , Chris Carilli , Bojan Nikolic

Direct detection of the Epoch of Reionization (EoR) via the red-shifted 21-cm line will have unprecedented implications on the study of structure formation in the infant Universe. To fulfill this promise, current and future 21-cm…

宇宙学与河外天体物理 · 物理学 2017-12-27 Abhik Ghosh , Florent Mertens , Leon V. E. Koopmans

We present here 21 cm predictions from high dynamic range simulations for a range of reionization histories that have been tested against available Lyman-alpha and CMB data. We assess the observability of the predicted spatial 21 cm…

星系天体物理 · 物理学 2016-09-13 Girish Kulkarni , Tirthankar Roy Choudhury , Ewald Puchwein , Martin G. Haehnelt

We provide perturbation theory predictions for the HI intensity mapping power spectrum multipoles using the Effective Field Theory of Large Scale Structure (EFTofLSS), which should allow us to constrain cosmological parameters exploiting…

宇宙学与河外天体物理 · 物理学 2023-02-02 Alkistis Pourtsidou

We present an efficient implementation of Wiener filtering of real-space linear field and optimal quadratic estimator of its power spectrum Band-powers. We first recast the field reconstruction into an optimization problem, which we solve…

宇宙学与河外天体物理 · 物理学 2019-10-16 Benjamin Horowitz , Uros Seljak , Grigor Aslanyan

The Epoch of Reionization (EoR), when the first luminous sources ionised the intergalactic medium, represents a new frontier in cosmology. The Square Kilometre Array Observatory (SKAO) will offer unprecedented insights into this era through…

Many high power electronic devices operate in a regime where the current they draw is limited by the self-fields of the particles. This space-charge-limited current poses particular challenges for numerical modeling where common techniques…

等离子体物理 · 物理学 2020-07-07 Peter H. Stoltz , John W. Luginsland , Andrew M. Chap , David N. Smithe , John R. Cary

Mapping of the neutral hydrogen (HI) 21-cm intensity fluctuations across redshifts promises a novel and powerful probe of cosmology. The neutral hydrogen gas mass density, $\Omega_{\rm HI}$ and bias parameter, $b_{\rm HI}$ are key…

宇宙学与河外天体物理 · 物理学 2015-03-10 Hamsa Padmanabhan , T. Roy Choudhury , Alexandre Refregier

We present a new class of estimators for computing small-scale power spectra and bispectra in configuration-space via weighted pair- and triple-counts, with no explicit use of Fourier transforms. Particle counts are truncated at $R_0\sim…

宇宙学与河外天体物理 · 物理学 2019-12-30 Oliver H. E. Philcox , Daniel J. Eisenstein

The high-redshift 21-cm signal of neutral hydrogen is expected to be observed within the next decade and will reveal epochs of cosmic evolution that have been previously inaccessible. Due to the lack of observations, many of the…

宇宙学与河外天体物理 · 物理学 2018-05-16 Aviad Cohen , Anastasia Fialkov , Rennan Barkana

Cosmic shear tomography has emerged as one of the most promising tools to both investigate the nature of dark energy and discriminate between General Relativity and modified gravity theories. In order to successfully achieve these goals,…

宇宙学与河外天体物理 · 物理学 2014-03-05 V. F. Cardone , M. Martinelli , E. Calabrese , S. Galli , Z. Huang , R. Maoli , A. Melchiorri , R. Scaramella

The GMRT reionization effort aims to map out the large scale structure of the Universe during the epoch of reionization (EoR). Removal of polarized Galactic emission is a difficult part of any 21 cm EoR program, and we present new upper…