Article
Astronomy & Astrophysics
Timur Takhtaganov, Zarija Lukic, Juliane Mueller, Dmitriy Morozov
Summary: In this paper, a novel statistical framework utilizing multi-output Gaussian process emulators adaptively constructed using Bayesian optimization methods is proposed to maintain low emulation error in the region of the hypercube preferred by observational data. The approach allows for fewer simulations compared to traditional emulation methods and is more robust in reconstructing parameters and their Bayesian credible intervals, as demonstrated with a Ly alpha forest flux power spectrum.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Anjan A. Sen, Shahnawaz A. Adil, Somasri Sen
Summary: This study explores the possibility of a negative cosmological constant in the Universe and finds that it is consistent with observational data.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Barun Maity, Tirthankar Roy Choudhury
Summary: One of the most promising ways to study the reionization history of the universe is through the power spectrum of neutral hydrogen 21 cm emission fluctuations. In this study, we use a seminumerical code called SCRIPT to model reionization and investigate its ability to constrain the parameters. Our findings show that the model is accurate and insensitive to the resolution of the simulation, and we also develop a simple template model that can reliably recover the global reionization history.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yizhou He, Philip Mansfield, Markus Michael Rau, Hy Trac, Nicholas Battaglia
Summary: An updated model for average cluster pressure profile has been proposed, incorporating results from X-ray observations and cosmological simulations to correct hydrostatic mass bias. Analysis of existing data using this model reveals adjustments to previously inferred values for cluster masses and pressures.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Suman Chatterjee, Somnath Bharadwaj, Samir Choudhuri, Shiv Sethi, Akash Kumar Patwa
Summary: Intensity mapping with the redshifted 21-cm line is a promising tool in cosmology, and the Tracking Tapered Grided Estimator (TTGE) has been developed to quantify the power spectrum of the sky signal in drift scan radio interferometric observations. The TTGE utilizes data from different pointing centers to estimate the power spectrum of the signal from a small angular region around a fixed tracking center, providing accurate results in recovering the input model angular power spectrum.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Reginald Christian Bernardo, Che-Yu Chen, Jackson Levi Said, Yu-Hsien Kung
Summary: This study investigates the effects of quantum fluctuations on the late Universe and explores a representative model with quantum fluctuations embedded in modified gravitational theories. The results suggest mild support for quantum corrections in cosmological models.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
N. Menci, M. Castellano, P. Santini, E. Merlin, A. Fontana, F. Shankar
Summary: Early observations with JWST have led to the discovery of a significantly large density of massive galaxies, which has important implications for cosmology and imposes strong constraints on the expansion history of the universe and dynamical dark energy models.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
Madhurima Choudhury, Abhirup Datta, Suman Majumdar
Summary: In this work, artificial neural networks (ANNs) are used to extract the HI 21-cm power spectrum and reionization parameters from synthetic datasets. This novel approach demonstrates a potential solution to the challenge of bright foregrounds in low-frequency radio interferometers.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Physics, Multidisciplinary
Jinyi Liu, Zeyang Sun, Jiakang Han, Julien Carron, Jacques Delabrouille, Siyu Li, Yang Liu, Jing Jin, Shamik Ghosh, Bin Yue, Pengjie Zhang, Chang Feng, Zhi-Qi Huang, Hao Liu, Yi-Wen Wu, Le Zhang, Zi-Rui Zhang, Wen Zhao, Bin Hu, Hong Li, Xinmin Zhang
Summary: AliCPT-1 is the first Chinese cosmic microwave background experiment aiming for high-precision measurement of CMB B-mode polarization. This study forecasts the signal-to-noise ratio of CMB lensing reconstruction, lensing-galaxy, and lensing-cosmic infrared background cross-correlations for AliCPT-1. The results show that the measurement significance increases with longer observation times and optimizing frequency data can improve the signal-to-noise ratio.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Astronomy & Astrophysics
Rajendra P. Gupta
Summary: Deep space observations of the JWST suggest that very early Universe galaxies may be as evolved as galaxies that have existed for much longer, which contradicts the Lambda CDM cosmological model. While tired light models explain the JWST data, they don't account for other observations like isotropy of the cosmic microwave background. Hybrid models that combine tired light and Lambda CDM have been proposed, with covarying coupling constants and yielding a stretched age of the Universe that resolves the "impossible early galaxy" problem.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Yuan He, Yu Pan, Dong-Ping Shi, Jin Li, Shuo Cao, Wei Cheng
Summary: This paper proposes an improved method to determine cosmic curvature using simulated data from DECIGO, providing reliable constraints on cosmic curvature and reducing estimation biases.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
T. N. Varga, D. Gruen, S. Seitz, N. MacCrann, E. Sheldon, W. G. Hartley, A. Amon, A. Choi, A. Palmese, Y. Zhang, M. R. Becker, J. McCullough, E. Rozo, E. S. Rykoff, C. To, S. Grandis, G. M. Bernstein, S. Dodelson, K. Eckert, S. Everett, R. A. Gruendl, I. Harrison, K. Herner, R. P. Rollins, I. Sevilla-Noarbe, M. A. Troxel, B. Yanny, J. Zuntz, H. T. Diehl, M. Jarvis, M. Aguena, S. Allam, J. Annis, E. Bertin, S. Bhargava, D. Brooks, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, M. Costanzi, L. N. da Costa, M. E. S. Pereira, J. De Vicente, S. Desai, J. P. Dietrich, I. Ferrero, B. Flaugher, J. Garcia-Bellido, E. Gaztanaga, D. W. Gerdes, J. Gschwend, G. Gutierrez, S. R. Hinton, K. Honscheid, T. Jeltema, K. Kuehn, N. Kuropatkin, M. A. G. Maia, M. March, P. Melchior, F. Menanteau, R. Miquel, R. Morgan, J. Myles, F. Paz-Chinchon, A. A. Plazas, A. K. Romer, E. Sanchez, V. Scarpine, M. Schubnell, S. Serrano, M. Smith, M. Soares-Santos, E. Suchyta, M. E. C. Swanson, G. Tarle, D. Thomas, J. Weller
Summary: We have developed a novel data-driven method for generating synthetic optical observations of galaxy clusters. By measuring and modeling the photometric properties of galaxy clusters and extrapolating the galaxy populations, we can create synthetic galaxy clusters in the same format as actual survey observations. This method can be used to test systematic uncertainties in cluster mass measurements.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Amber M. Hollinger, Michael J. Hudson
Summary: A promising method for measuring the cosmological parameter combination f(8)(sigma) is to compare observed peculiar velocities with predicted velocities using perturbation theory. Despite small systematic biases, the method is accurate and precise, with cosmic variance affecting current measurements due to the volume of redshift data sets.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Elcio Abdalla, Elisa G. M. Ferreira, Ricardo G. Landim, Andre A. Costa, Karin S. F. Fornazier, Filipe B. Abdalla, Luciano Barosi, Francisco A. Brito, Amilcar R. Queiroz, Thyrso Villela, Bin Wang, Carlos A. Wuensche, Alessandro Marins, Camila P. Novaes, Vincenzo Liccardo, Chenxi Shan, Jiajun Zhang, Zhongli Zhang, Zhenghao Zhu, Ian Browne, Jacques Delabrouille, Larissa Santos, Marcelo dos Santos, Haiguang Xu, Sonia Anton, Richard Battye, Tianyue Chen, Clive Dickinson, Yin-Zhe Ma, Bruno Maffei, Eduardo J. de Mericia, Pablo Motta, Carlos H. N. Otobone, Michael W. Peel, Sambit Roychowdhury, Mathieu Remazeilles, Rafael M. Ribeiro, Yu Sang, Joao R. L. Santos, Juliana F. R. dos Santos, Gustavo B. Silva, Frederico Vieira, Jordany Vieira, Linfeng Xiao, Xue Zhang, Yongkai Zhu
Summary: The BINGO project is a unique radio telescope designed to study cosmology and astrophysics through observations of the redshifted 21-cm line of neutral hydrogen. It aims to detect the low redshift baryon acoustic oscillations (BAO) to constrain dark matter models and test the Lambda CDM model. The project utilizes intensity mapping to create a 3D map of the neutral hydrogen distribution and has the potential to discover fast radio bursts (FRBs) and other transients.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Hakim Atek, Marko Shuntov, Lukas J. Furtak, Johan Richard, Jean-Paul Kneib, Guillaume Mahler, Adi Zitrin, H. J. McCracken, Stephane Charlot, Jacopo Chevallard, Iryna Chemerynska
Summary: One of the main goals of the JWST is to study the first galaxies in the Universe. Through a systematic photometric analysis, we have discovered two galaxy candidates at z similar to 16, only 250 million years after the big bang. We have also identified candidates at z similar to 12 and z similar to 9-11, demonstrating the capabilities of JWST to uncover photometric candidates at very high redshifts.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Jin-Ling Geng, Yu Zhang, En-Kun Li, Peng-Fei Duan
ASTROPHYSICS AND SPACE SCIENCE
(2015)
Article
Astronomy & Astrophysics
Jin-Ling Geng, Yu Zhang, En-Kun Li, Peng-Fei Duan
ASTROPHYSICS AND SPACE SCIENCE
(2015)
Article
Astronomy & Astrophysics
En-Kun Li, Yu Zhang, Jin-Ling Geng, Peng-Fei Duan
GENERAL RELATIVITY AND GRAVITATION
(2015)
Article
Astronomy & Astrophysics
Jin-Ling Geng, Yu Zhang, En-Kun Li, Peng-Fei Duan
MODERN PHYSICS LETTERS A
(2016)
Article
Astronomy & Astrophysics
En-Kun Li, Yu Zhang, Jin-Ling Geng, Peng-Fei Duan
ASTROPHYSICS AND SPACE SCIENCE
(2015)
Article
Astronomy & Astrophysics
Yu Zhang, En-Kun Li, Jin-Ling Geng
GENERAL RELATIVITY AND GRAVITATION
(2014)
Article
Astronomy & Astrophysics
Yu Zhang, Jin-Ling Geng, En-Kun Li
MODERN PHYSICS LETTERS A
(2014)
Article
Astronomy & Astrophysics
En-Kun Li, Yu Zhang, Jin-Ling Geng
Article
Physics, Multidisciplinary
Liang-Gui Zhu, Ling-Hua Xie, Yi-Ming Hu, Shuai Liu, En-Kun Li, Nicola R. Napolitano, Bai-Tian Tang, Jian-Dong Zhang, Jianwei Mei
Summary: This study comprehensively investigates the ability to infer the Hubble constant using gravitational wave events, finding that a multi-detector network involving TianQin and LISA can achieve high precision. Additionally, high-quality spectroscopic redshift information is crucial for improving estimation precision.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Astronomy & Astrophysics
Yang Lu, En-Kun Li, Yi-Ming Hu, Jian-dong Zhang, Jianwei Mei
Summary: This paper presents a method to search for double white dwarfs in MLDC-3.1 data using an iterative combinatorial algorithm. The combination of coarse and fine search processes allows for efficient determination of the target sources' parameters, and we successfully detect (SIC)(10(4)) double white dwarf signals.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Yuhao Mu, En-Kun Li, Lixin Xu
Summary: In this paper, the reconstructed growth index is updated using a combination of Pantheon+ SNe Ia samples, observed Hubble data points, and redshift space distortion measurements. The results suggest a mild time varying growth index at low redshifts within the available data points. No significant deviation from the ΛCDM cosmology in GR was found within the 3 sigma regions, while the growth indices for f(R) and Dvali-Gabadadze-Porrati gravity are at the boundaries of the 3 sigma regions.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Shun-Jia Huang, Yi-Ming Hu, Xian Chen, Jian-dong Zhang, En-Kun Li, Zucheng Gao, Xin-yi Lin
Summary: This work proposes a new method to constrain the Hubble constant using strongly lensed gravitational wave (SLGW) signals. The lensed waveform is found to be sensitive to H-0 through reparameterization. Even in scenarios where no electromagnetic counterpart of the GW source can be identified, meaningful constraints on H-0 can still be obtained using the information of the lens redshift. The potential of this method is evaluated using Fisher information matrix and Markov Chain Monte Carlo, and it is found that the H-0 can be constrained within a relative error of about 1% with a single SLGW event for the space-based GW detector TianQin.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Zheng-Cheng Liang, Zhi-Yuan Li, Jun Cheng, En-Kun Li, Jian-dong Zhang, Yi-Ming Hu
Summary: The method of time-delay interferometry (TDI) is proposed to cancel the laser noise in space-borne gravitational-wave detectors. The most commonly used TDI combinations are the orthogonal channels A, E, and T, where A and E are signal-sensitive and T is signal-insensitive. The exact form of overlap reduction function for A/E channels is derived, and the sensitivity curves of TianQin, TianQin I + II, and TianQin + LISA are calculated based on the overlap reduction function. The detection sensitivity calculated with A/E channels is mostly consistent with that obtained from the equal-arm Michelson channels.
Article
Astronomy & Astrophysics
Jun Cheng, En-Kun Li, Yi-Ming Hu, Zheng-Cheng Liang, Jian-dong Zhang, Jianwei Mei
Summary: In this work, a data analysis software called TQSGWB is developed to extract isotropic SGWB using the Bayes analysis method based on the TianQin detector. It is found that the imaginary components in the noise cross spectrum play an important role in breaking the degeneracy of the position noise. After considering the imaginary corrections, the credible regions of the position noise parameters are reduced significantly. With only a three-month observation, TianQin could confidently detect SGWBs with low energy density.