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We show that the epoch(s) of reionization when the ionization fraction of the universe is about half can be determined by correlating Cosmic Microwave Background (CMB) temperature maps with 21-cm line maps at degree scales ($l\sim 100$).…

Astrophysics · Physics 2009-11-13 Marcelo A. Alvarez , Eiichiro Komatsu , Olivier Doré , Paul R. Shapiro

We explore a systematic approach to the analysis of primordial non-Gaussianity using fluctuations in temperature and polarization of the Cosmic Microwave Background (CMB). Following Munshi & Heavens (2009), we define a set of power-spectra…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Dipak Munshi , Peter Coles , Asantha Cooray , Alan Heavens , Joseph Smidt

We measure the skewness power spectrum of the Cosmic Microwave Background (CMB) anisotropies optimized for a detection of the secondary bispectrum generated by the correlation of the CMB lensing potential with integrated Sachs-Wolfe effect…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-29 Erminia Calabrese , Joseph Smidt , Alexandre Amblard , Asantha Cooray , Alessandro Melchiorri , Paolo Serra , Alan Heavens , Dipak Munshi

Since the first limit on the (local) primordial non-Gaussianity parameter, fNL, was obtained from COBE data in 2002, observations of the CMB have been playing a central role in constraining the amplitudes of various forms of non-Gaussianity…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Eiichiro Komatsu

The curl (B) modes of cosmic microwave background (CMB) polarization anisotropies are a unique probe of the primordial background of inflationary gravitational waves (IGWs). Unfortunately, the B-mode polarization anisotropies generated by…

Astrophysics · Physics 2007-05-23 Kris Sigurdson , Asantha Cooray

Measurement of the cosmic microwave background (CMB) bispectrum, or three-point correlation function, has now become one of the principle efforts in early-Universe cosmology. Here we show that there is a odd-parity component of the CMB…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-03 Marc Kamionkowski , Tarun Souradeep

The leading candidate for the very early universe is described by a period of rapid expansion known as inflation. While the standard paradigm invokes a single slow-rolling field, many different models may be constructed which fit the…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-30 D. M. Regan

Spectral distortions of the Cosmic Microwave Background (CMB) offer the possibility of probing processes which occurred during the evolution of our Universe going back up to Z$\simeq 10^7$. Unfortunately all the attempts so far carried out…

Instrumentation and Methods for Astrophysics · Physics 2017-02-22 Giorgio Sironi

Local non-Gaussianities in the initial conditions of the Universe, parameterized by $f_{\rm NL}$, induce a scale-dependence in the large-scale bias of halos in the late Universe. This effect is a promising path to constrain multi-field…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-04 Fiona McCarthy , Mathew S. Madhavacheril , Abhishek S. Maniyar

Primordial black holes (PBHs) would induce non-Gaussianity in the cosmic microwave background (CMB) by sourcing recombination perturbations spatially modulated by relative velocities between PBHs and the baryons they accrete. The leading…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-11 Trey W. Jensen , Yacine Ali-Haïmoud

Some analyses of recent cosmic microwave background (CMB) data have provided hints that there are deviations from Gaussianity in the WMAP CMB temperature fluctuations. Given the far reaching consequences of such a non-Gaussianity for our…

Astrophysics · Physics 2009-03-31 A. Bernui , M. J. Reboucas

We discuss the issue of how precisely we can measure the primordial power spectrum by using future observations of 21 cm fluctuations and cosmic microwave background (CMB). For this purpose, we investigate projected constraints on the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Kazunori Kohri , Yoshihiko Oyama , Toyokazu Sekiguchi , Tomo Takahashi

Following the pioneering observations with COBE in the early 1990s, studies of the cosmic microwave background (CMB) have focused on temperature and polarization anisotropies. CMB spectral distortions - tiny departures of the CMB energy…

Measurements from the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission 2 (ARCADE-2) reveal a strong radio background in the GHz frequency range. Since the cosmological 21-cm signal is measured relative to the background…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-17 Sudipta Sikder , Rajesh Mondal , Rennan Barkana , Anastasia Fialkov

I will discuss to what degree the cosmic microwave background (CMB) can be used to constrain primordial non-Gaussianity involving one tensor and two scalar fluctuations, focusing on the correlation of one $B$-mode polarization fluctuation…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-18 P. Daniel Meerburg

Assuming a slow-roll inflationary model where conformal invariance of the Maxwell action is broken via a non-minimal kinetic coupling term, we investigate the non-Gaussian three-point cross-correlation function between the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-08 Arko Bhaumik , Supratik Pal

Upcoming cosmic microwave background (CMB) data can be used to explore harmonic 3-point functions that involve the B-mode component of the CMB polarization signal. We focus on bispectra describing the non-Gaussian correlation of the B-mode…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-15 Adriaan J. Duivenvoorden , P. Daniel Meerburg , Katherine Freese

The cross-correlation between cosmic microwave background (CMB) gravitational lensing and large-scale structure tracers will be an important cosmological probe in the coming years. Quadratic estimators provide a simple and powerful (if…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-10 Giulio Fabbian , Antony Lewis , Dominic Beck

The cosmic 21-cm background frequency spectrum related to the spin-flip transition of neutral Hydrogen present during and before the era of reionization is rich in features associated with physical processes that govern transitions between…

Astrophysics · Physics 2010-11-26 Asantha Cooray

Next-generation galaxy surveys will be able to measure perturbations on scales beyond the equality scale. On these ultra-large scales, primordial non-Gaussianity leaves signatures that can shed light on the mechanism by which perturbations…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-10 Mario Ballardini , William Luke Matthewson , Roy Maartens