Article
Astronomy & Astrophysics
Selim C. Hotinli, Joel Meyers, Cynthia Trendafilova, Daniel Green, Alexander van Engelen
Summary: Delensing CMB data can improve inferences on cosmological parameters, primary gravitational waves, and non-Gaussianities, while simplifying analysis. It offers various benefits without any changes to experimental or survey design.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
William Giare, Matteo Forconi, Eleonora Di Valentino, Alessandro Melchiorri
Summary: This paper analyzes the inflationary gravitational waves, which act as additional radiation in the Early Universe and can increase the effective number of relativistic species (N-eff) through a correction based on the integrated energy-density in gravitational waves across all scales. The study demonstrates that the calculation is dominated by the behavior of the tensor spectrum on scales corresponding to modes that cross the horizon very close to the end of inflation, making it strongly model dependent. The researchers use a theoretical Monte Carlo approach within the framework of the Effective Field Theory of inflation to investigate the observable predictions of various models, proving that accurate analyses are necessary to obtain reliable information on the inflationary Universe.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Hsin-Yu Chen, Carl-Johan Haster, Salvatore Vitale, Will M. Farr, Maximiliano Isi
Summary: This study explores the possibility of inferring cosmological parameters using the standard siren ZTF19abanrhr, which is associated with the binary black hole merger GW190521. The results provide estimates of the Hubble constant and matter density under different models and priors.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Paolo Campeti, Eiichiro Komatsu, Davide Poletti, Carlo Baccigalupi
Summary: This study investigates the potential of measuring the primordial gravitational wave signal using various instruments and missions, such as CMB, PTA, and interferometers. Sensitivity curves and error bars for different models are presented, showing promising prospects for joint measurements by CMB and space-borne interferometers. The effect of astrophysical foreground contamination in each experiment is also evaluated.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
Massimo Giovannini
Summary: This paper investigates the impact of increasing refractive index of relic gravitons during the stage of inflationary evolution on the spectral energy density. It also explores the relationship between these potential evidence and the peculiar signatures observed with pulsar timing arrays. The results suggest that pulsar timing arrays are sensitive to the evolution of the refractive index during early stages of inflation.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Jacopo Fumagalli, Mauro Pieroni, Sebastien Renaux-Petel, Lukas T. Witkowski
Summary: In this study, the detection prospects of oscillations in the frequency profile of the stochastic gravitational wave background are investigated using the upcoming space-based gravitational wave observatory LISA. It is found that the oscillations can be reconstructed with LISA, and it is confirmed that they are a worthwhile target for future detection efforts and offer a key for experimentally testing inflation at small scales.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Sunny Vagnozzi
Summary: The NANOGrav pulsar timing array experiment provides evidence for a potential detection of a stochastic gravitational wave background, with implications for matching the upper limits set by BICEP2/Keck Array and Planck. Results suggest the existence of a parameter space related to big bang nucleosynthesis constraints.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Yan-Jin Wang, Jing-Zhao Qi, Bo Wang, Jing-Fei Zhang, Jing-Lei Cui, Xin Zhang
Summary: Independently measuring cosmic curvature is crucial in cosmology, and gravitational waves can provide distance calibration in the strong gravitational lensing method, enhancing precision and coverage.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jiming Chen, Shamik Ghosh, Wen Zhao
Summary: In this article, a new unbiased estimator, called the QLM-SZ estimator, is presented for estimating the cross-correlation power spectra of the cosmic microwave background. This estimator combines the Smith-Zaldarriaga approach and the scalar QML approach to achieve lower computational cost and faster running time.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2022)
Article
Astronomy & Astrophysics
Massimo Giovannini
Summary: Cosmic gravitons are expected to be detected in the MHz-GHz frequency regions, where wide-band interferometers and various classes of electromagnetic detectors have been proposed. Previous sensitivity requirements for these detectors have been based on the reachable sensitivities of audio band detectors, but we show that these requirements are too generous. We argue that high-frequency detectors are more essential for investigating the quantum properties of relic gravitons and their second-order correlation effects.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Pauline Vielzeuf, Matteo Calabrese, Carmelita Carbone, Giulio Fabbian, Carlo Baccigalupi
Summary: Cosmic voids are powerful probes of cosmology, especially in studying the nature of gravity and the neutrino mass. Recent studies have shown that measurements of void imprint on the lensed Cosmic Microwave Background (CMB) are in tension with expectations based on simulations, suggesting the possibility of non-standard cosmological signatures due to massive neutrinos. This study uses cosmological simulations with massive neutrino cosmologies to investigate the impact of neutrinos on void properties observed in photometric surveys and the void-CMB lensing cross-correlation. The results provide insights into the potential role of massive neutrinos in explaining the tension observed and propose a new quantity for distinguishing different neutrino masses through future observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Zhuoqi (Jackie) Zhang, Yuuki Omori, Chihway Chang
Summary: This study examines the probability density function of the cosmic microwave background (CMB) convergence field and finds that the overall distribution is slightly non-Gaussian due to primordial non-Gaussianities and contributions from structures at low redshifts. By modelling the distribution of galaxies and subtracting the late-time component from the original CMB lensing map, a high-redshift mass map is obtained, allowing for the direct study of early phases of structure formation. The detectability of non-Gaussianity signatures from non-linear structure formation at z > 1.2 is forecasted in this work, and it is found that current surveys may face challenges in detecting such signatures, while future experiments like the deep field of CMB-S4 will have the capability to make detections at & SIM;7 & sigma;.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Alex Krolewski, Simone Ferraro, Martin White
Summary: Recent lensing measurements at low redshifts suggest that the amplitude of lensing in the universe may be lower than predicted by the Lambda CDM model based on Planck CMB data. By analyzing the auto-and cross-correlation signal of unWISE galaxies and Planck CMB lensing maps, cosmological parameters at low redshifts have been inferred, showing tensions with the CMB predictions. The combination of blue, green, and red unWISE samples gives a value of S-8 = 0.784 +/- 0.015, consistent with other low-redshift lensing measurements and in tension with the CMB predictions from Planck.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
S. Azzoni, D. Alonso, M. H. Abitbol, J. Errard, N. Krachmalnicoff
Summary: The future ground-based and satellite-borne experiments hope to indirectly detect the signal from primordial tensor fluctuations through observing the polarised emission from the Cosmic Microwave Background (CMB). However, accurately separating the signal from polarised Galactic foregrounds is crucial. This study presents a component separation method for multi-frequency CMB observations that can effectively reduce contamination from Galactic foregrounds below an equivalent tensor-to-scalar ratio rFG <= 5x10-4.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Swagat S. Mishra, Varun Sahni, Alexei A. Starobinsky
Summary: In this study, the authors discuss degeneracies in inflationary cosmology predictions for CMB observables and demonstrate how constraints on post-inflationary reheating parameters can break this degeneracy in certain inflationary models. The study also shows how relic gravitational waves provide valuable information about the post-inflationary epoch and can be used to cure inflationary degeneracies in {n(S), r}. Through considering reheating parameters and relic gravitational waves, various inflationary degeneracies can be addressed and resolved.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
Wen Zhao, Tan Liu, Linqing Wen, Tao Zhu, Anzhong Wang, Qian Hu, Cong Zhou
EUROPEAN PHYSICAL JOURNAL C
(2020)
Article
Astronomy & Astrophysics
Larissa Santos, Jian Yao, Le Zhang, Shamik Ghosh, Pengjie Zhang, Wen Zhao, Thyrso Villela, Jiming Chen, Jacques Delabrouille
Summary: In this study, the ABS method was applied to simulated sky maps to test its capability of determining the CMB polarization E- and B-mode power spectra. The method performed well for full-sky observations at intermediate and small angular scales, despite strong foreground contamination, but extra work is needed for partial sky analyses to reduce biases and confusion between CMB E and B polarization.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Jiming Yu, Haoran Song, Shunke Ai, He Gao, Fayin Wang, Yu Wang, Youjun Lu, Wenjuan Fang, Wen Zhao
Summary: This study investigates the optical and electromagnetic counterparts of binary neutron star mergers, discussing the rates and distributions of multimessenger observations in different generations of GW detectors. Results show that these events have lower redshifts and inclination angles.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Rui Niu, Xing Zhang, Bo Wang, Wen Zhao
Summary: The article examines constraints on three scalar-tensor theories through gravitational wave observations, analyzing two neutron star-black hole events to draw conclusions. The research finds that the constraints provided by GWs are comparable to pulsar timing experiments for the DEF theory, but not competitive for the BD and SMG theories.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Jiming Chen, Shamik Ghosh, Hao Liu, Larissa Santos, Wenjuan Fang, Siyu Li, Yang Liu, Hong Li, Jiaxin Wang, Le Zhang, Bin Hu, Wen Zhao
Summary: Two new QML methods, QML-SZ and QML-TC, are proposed for B-mode power spectrum estimation in this article. These estimators have similar error bars as the traditional QML estimator but with significantly lower computational cost, allowing for the construction of pure B-mode CMB maps using different approaches.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2021)
Article
Astronomy & Astrophysics
Jiming Chen, Shamik Ghosh, Wen Zhao
Summary: In this article, a new unbiased estimator, called the QLM-SZ estimator, is presented for estimating the cross-correlation power spectra of the cosmic microwave background. This estimator combines the Smith-Zaldarriaga approach and the scalar QML approach to achieve lower computational cost and faster running time.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2022)
Article
Astronomy & Astrophysics
Zheng-Yan Liu, Zhe-Yu Lin, Ji-Ming Yu, Hui-Yu Wang, Gibran-Marc Mourani, Wen Zhao, Zi-Gao Dai
Summary: This article investigates the detection capabilities of the Wide-Field Survey Telescope (WFST) for kilonovae through simulated images. The results show that WFST performs better in the g and r bands and can detect 90% (50%) of kilonovae at a luminosity distance of 248 Mpc (338 Mpc) with 30 s exposures when kilonovae are at peak luminosity.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Yi-Fan Wang, Stephanie M. Brown, Lijing Shao, Wen Zhao
Summary: We report the results of testing gravitational-wave birefringence using the largest population of gravitational-wave events currently available. The study found no evidence for a violation of general relativity in the majority of events, but observed intriguing nonzero results for gravitational-wave birefringence in the two most massive events. The findings contribute to a better understanding of modified gravity and possible alternative explanations.
Article
Astronomy & Astrophysics
Aoxiang Jiang, Wei Liu, Wenjuan Fang, Wen Zhao
Summary: This study analyzes the Minkowski functionals (MFs) of large-scale structures using N-body simulations and finds that they can provide competitive constraints on cosmological parameters, especially on nonlinear scales.
Article
Astronomy & Astrophysics
Cheng Gong, Tao Zhu, Rui Niu, Qiang Wu, Jiang-Lei Cui, Xin Zhang, Wen Zhao, Anzhong Wan
Summary: This paper investigates the effects of high-order spatial derivatives on the propagation of gravitational waves due to Lorentz and parity violation. Bayesian inference is performed using modified waveforms and observational data from selected GW events to place lower bounds on the energy scales for Lorentz and parity violation. The results do not find significant evidence of Lorentz and parity violation at the fifth and sixth-order spatial derivatives terms.
Article
Astronomy & Astrophysics
Qiang Wu, Tao Zhu, Rui Niu, Wen Zhao, Anzhong Wang
Summary: This paper investigates the parity violating effects on gravitational wave propagation in Nieh-Yan modified teleparallel gravity. No significant deviation from general relativity is found, placing an upper bound on the energy scale of the Nieh-Yan term.
Article
Astronomy & Astrophysics
Qian Hu, Mingzheng Li, Rui Niu, Wen Zhao
Summary: This study numerically estimates the potential capabilities of future networks of multiple space-based detectors using Bayesian analysis, finding that detector networks significantly improve source localization accuracy and have similar effects as individual detectors in constraining the parity symmetry of gravity.
Article
Astronomy & Astrophysics
Bo Wang, Zhenyu Zhu, Ang Li, Wen Zhao
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2020)
Article
Astronomy & Astrophysics
Jin Qiao, Tao Zhu, Wen Zhao, Anzhong Wang
Article
Astronomy & Astrophysics
Wen Zhao, Tao Zhu, Jin Qiao, Anzhong Wang
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.
