Yin-Zhe Ma
A5005940677- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Black Holes and Theoretical Physics
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Computational Physics and Python Applications
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Astronomical Observations and Instrumentation
- Particle physics theoretical and experimental studies
- Antenna Design and Optimization
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Relativity and Gravitational Theory
- Superconducting and THz Device Technology
- Statistical and numerical algorithms
- Radio Wave Propagation Studies
University of KwaZulu-Natal
2016-2025
Stellenbosch University
2023-2025
National Institute for Theoretical Physics
2022-2024
Purple Mountain Observatory
2017-2023
Chinese Academy of Sciences
2008-2023
Xinjiang Astronomical Observatory
2023
California Institute of Technology
2017-2020
University of Manchester
2015-2020
SKA Observatory
2015-2017
University of British Columbia
2012-2016
We report on the implications for cosmic inflation of 2018 Release Planck CMB anisotropy measurements. The results are fully consistent with two previous cosmological releases, but have smaller uncertainties thanks to improvements in characterization polarization at low and high multipoles. temperature, polarization, lensing data determine spectral index scalar perturbations be $n_\mathrm{s}=0.9649\pm 0.0042$ 68% CL show no evidence a scale dependence $n_\mathrm{s}.$ Spatial flatness is...
We describe the legacy Planck cosmic microwave background (CMB) likelihoods derived from 2018 data release. The overall approach is similar in spirit to one retained for 2013 and 2015 release, with a hybrid method using different approximations at low ( ℓ < 30) high ≥ multipoles, implementing several methodological data-analysis refinements compared previous releases. With more realistic simulations, better correction modelling of systematic effects, we can now make full use CMB...
We present measurements of the cosmic microwave background (CMB) lensing potential using final Planck 2018 temperature and polarization data. Using maps filtered to account for noise anisotropy, we increase significance detection in from 5 σ 9 . Combined with temperature, is detected at 40 an extensive set tests robustness lensing-potential power spectrum, construct a minimum-variance estimator likelihood over multipoles 8 ≤ L 400 (extending range lower compared 2015), which use constrain...
We analyse the Planck full-mission cosmic microwave background (CMB) temperature and E -mode polarization maps to obtain constraints on primordial non-Gaussianity (NG). compare estimates obtained from separable template-fitting, binned, optimal modal bispectrum estimators, finding consistent values for local, equilateral, orthogonal amplitudes. Our combined analysis produces following final results: f NL local = −0.9 ± 5.1; equil −26 47; ortho −38 24 (68% CL, statistical). These results...
Analysis of the Planck 2018 data set indicates that statistical properties cosmic microwave background (CMB) temperature anisotropies are in excellent agreement with previous studies using 2013 and 2015 releases. In particular, they consistent Gaussian predictions $Λ$CDM cosmological model, yet also confirm presence several so-called "anomalies" on large angular scales. The novelty current study, however, lies being a first attempt at comprehensive analysis statistics polarization signal...
We investigate constraints on cosmic reionization extracted from the Planck microwave background (CMB) data. combine CMB anisotropy data in temperature with low-multipole polarization to fit LCDM models various parameterizations of history. obtain a Thomson optical depth tau=0.058 +/- 0.012 for commonly adopted instantaneous model. This confirms, only anisotropies, low value suggested by combining 2015 results other sets and also reduces uncertainties. reconstruct history ionization fraction...
We present full-sky maps of the cosmic microwave background (CMB) and polarized synchrotron thermal dust emission, derived from third set Planck frequency maps. These products have significantly lower contamination instrumental systematic effects than previous versions. The methodologies used to derive these follow those described in earlier papers, adopting four methods (Commander, NILC, SEVEM, SMICA) extract CMB component, as well three GNILC, astrophysical components. Our revised...
This paper presents the High Frequency Instrument (HFI) data processing procedures for Planck 2018 release. Major improvements in mapmaking have been achieved since previous 2015 They enabled first significant measurement of reionization optical depth parameter using HFI data. an extensive analysis systematic effects, including use simulations to facilitate their removal and characterize residuals. The polarized data, which presented a number known problems release, are very significantly...
Using the Planck 2015 data release (PR2) temperature maps, we separate Galactic thermal dust emission from cosmic infrared background (CIB) anisotropies. For this purpose, implement a specifically tailored component-separation method, so-called generalized needlet internal linear combination (GNILC) which uses spatial information (the angular power spectra) to disentangle and CIB We produce significantly improved all-sky maps of emission, with reduced contamination, at 353, 545, 857 GHz. By...
We analyse the Planck full-mission cosmic microwave background (CMB) temperature and E-mode polarization maps to obtain constraints on primordial non-Gaussianity (NG). compare estimates obtained from separable template-fitting, binned, modal bispectrum estimators, finding consistent values for local, equilateral, orthogonal amplitudes. Our combined analysis produces following results: f_NL^local = -0.9 +\- 5.1; f_NL^equil -26 47; f_NL^ortho - 38 24 (68%CL, statistical). These results include...
Abstract This paper explores the effect of Large Magellanic Cloud (LMC) on mass estimates obtained from timing argument. We show that accounting for presence LMC systematically lowers Local Group (MLG) derived relative motion Milky Way–Andromeda pair. Motivated by this result, we apply a Bayesian technique devised Peñarrubia et al. to simultaneously fit (i) distances and velocities galaxies within 3 Mpc (ii) between Way Andromeda HST observations, with (MLMC) as free parameter. Our analysis...
The study of polarized dust emission has become entwined with the analysis cosmic microwave background (CMB) polarization. We use new Planck maps to characterize Galactic as a foreground CMB present EE, BB, and TE power spectra polarization at 353 GHz for six nested sky regions covering from 24 71 % sky. power-law fits angular spectra, yielding evidence statistically significant variations exponents over difference between values EE BB spectra. correlation E/B asymmetry extend low multipoles...
Abstract Recently, the Hydrogen Epoch of Reionization Array (HERA) has produced experiment’s first upper limits on power spectrum 21 cm fluctuations at z ∼ 8 and 10. Here, we use several independent theoretical models to infer constraints intergalactic medium (IGM) galaxies during epoch reionization from these limits. We find that IGM must have been heated above adiabatic-cooling threshold by 8, uncertainties about ionization radio background. Combining HERA with complementary observations...
Abstract We report the most sensitive upper limits to date on 21 cm epoch of reionization power spectrum using 94 nights observing with Phase I Hydrogen Epoch Reionization Array (HERA). Using similar analysis techniques as in previously reported limits, we find at 95% confidence that Δ 2 ( k = 0.34 h Mpc −1 ) ≤ 457 mK z 7.9 and 0.36 3496 10.4, an improvement by a factor 2.1 2.6, respectively. These are mostly consistent thermal noise over wide range after our data quality cuts, despite...
The six parameters of the standard $Λ$CDM model have best-fit values derived from Planck temperature power spectrum that are shifted somewhat WMAP data. These shifts driven by features in at angular scales had never before been measured to cosmic-variance level precision. We investigate these determine whether they within range expectation and understand their origin Taking our parameter set be optical depth reionized intergalactic medium $τ$, baryon density $ω_{\rm b}$, matter m}$, size...
We present 353 GHz full-sky maps of the polarization fraction $p$, angle $\psi$, and dispersion angles $S$ Galactic dust thermal emission produced from 2018 release Planck data. confirm that mean maximum $p$ decrease with increasing $N_H$. The uncertainty on fraction, $p_\mathrm{max}=22.0$% at 80 arcmin resolution, is dominated by zero level in total intensity. observed inverse behaviour between interpreted models polarized sky include effects only topology turbulent magnetic field. Thus,...
Recently the Experiment to Detect Global Epoch of Reionization Signature reported detection a 21 cm absorption signal stronger than astrophysical expectations. In this paper we study impact radiation from dark matter (DM) decay and primordial black holes (PBHs) on temperature in reionization epoch, impose constraint decaying PBH energy injection intergalactic medium, which can heat up neutral hydrogen gas weaken signal. We assume strong coupling limit Lyman-$\ensuremath{\alpha}$ background...
We search the Planck data for a thermal Sunyaev-Zel'dovich (tSZ) signal due to gas filaments between pairs of Luminous Red Galaxies (LRG's) taken from Sloan Digital Sky Survey Data Release 12 (SDSS/DR12). identify $\sim$260,000 LRG in DR12 catalog that lie within 6-10 $h^{-1} \mathrm{Mpc}$ each other tangential direction and 6 radial direction. stack by rotating scaling angular positions so they on common reference frame, then we subtract circularly symmetric halo member pair residual...
We perform a detailed investigation on the cosmological constraints holographic dark energy (HDE) model by using Plank data. find that HDE can provide good fit to high-ℓ (ℓ ≳ 40) temperature power spectrum, while discrepancy at ℓ ≃ 20-40 found in ΛCDM remains unsolved model. The data alone lead strong and reliable constraint parameter c. At 68% confidence level (CL), we obtain c = 0.508 ± 0.207 with Plank+WP+lensing, favoring present phantom behavior of more than 2σ CL. By combining Plank+WP...
Abstract The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over wide range of frequencies, and with an order magnitude greater sensitivity survey speed than any current telescope. SKA will address many important topics in astronomy, ranging from planet formation distant galaxies. However, this work, we consider the perspective as facility for studying physics. We review four areas which expected make major contributions our understanding fundamental...
We combine the equations of motion that govern dynamics galaxies in local volume with Bayesian techniques order to fit orbits published distances and velocities within 3 Mpc. find a Local Group (LG) mass 2.3 ± 0.7 × 1012 M⊙ is consistent combined dynamical masses M31 Milky Way, ratio |$0.54^{+0.23}_{-0.17}$| rules out models where our Galaxy more massive than ∼95 per cent confidence. The Way's circular velocity at solar radius relatively high, 245 23 km s−1, which helps reconcile derived...