A5069594358- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Radio Astronomy Observations and Technology
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- High-pressure geophysics and materials
- Dark Matter and Cosmic Phenomena
- earthquake and tectonic studies
- GNSS positioning and interference
- Scientific Research and Discoveries
- Relativity and Gravitational Theory
- Statistical and numerical algorithms
- Statistical Mechanics and Entropy
- Astrophysics and Star Formation Studies
- Neutrino Physics Research
- Economic Growth and Productivity
- Complex Systems and Time Series Analysis
- Cancer Research and Treatments
Nanjing University
2016-2025
Astronomy and Space
2012-2025
Ministry of Education of the People's Republic of China
2015-2024
Purple Mountain Observatory
2016-2024
Hankou University
2012-2023
Yunnan University
2022
Chinese Academy of Sciences
2017-2021
Yunnan Observatories
2021
National Astronomical Observatories
2017
Nanjing General Hospital of Nanjing Military Command
2017
We compile a complete collection of reliable Hubble parameter $H(z)$ data to redshift $z \leq 2.36$ and use them with the Gaussian Process method determine continuous functions for various subsets. From these $H(z)$'s, summarizing across subsets considered, we find $H_0\sim 67 \pm 4\,\rm km/s/Mpc$, more consistent recent lower values determined using variety techniques. In most subsets, see cosmological deceleration-acceleration transition at 2$\sigma$ significance, redshifts varying over...
The ΛCDM model provides a good fit to most astronomical observations but harbors large areas of phenomenology and ignorance. With the improvements in precision number observations, discrepancies between key cosmological parameters this have emerged. Among them, notable tension is 4σ 6σ deviation Hubble constant (H0) estimations measured by local distance ladder cosmic microwave background (CMB) measurement. In review, we revisit H0 based on latest research sort out evidence from solutions...
The current discrepancy between the Hubble constant $H_0$ derived from local distance ladder and cosmic microwave background is one of most crucial issues in cosmology, as it possibly indicates unknown systematics or new physics. Here we present a novel non-parametric method to estimate function redshift. We establish independent estimates evolution by diagonalizing covariance matrix. From type Ia supernovae observed parameter data, decreasing trend with significance 5.6$\sigma$ confidence...
Abstract We report the observations of FRB 20220912A using Five-hundred-meter Aperture Spherical radio Telescope. conducted 17 totaling 8.67 hr and detected a total 1076 bursts with an event rate up to 390 −1 . The cumulative energy distribution can be well described broken power-law function lower- higher-energy slopes −0.38 ± 0.02 −2.07 0.07, respectively. also L -band (1–1.5 GHz) spectral index synthetic spectrum bursts, which is −2.6 0.21. average rotation measure value from −0.08 5.39...
Abstract The Dark Energy Spectroscopic Instrument (DESI) collaboration recently released the first-year data of baryon acoustic oscillations (BAOs). Based on five different tracers, cosmological constraint shows a hint deviation from standard ΛCDM model. In this Letter, we combine DESI BAOs with other cosmic probes to constrain evolution Hubble constant as function redshift in flat nonparametric method is used estimate value at bins. correlations among bins are removed by diagonalizing...
In this paper we propose that a fast radio burst (FRB) could originate from the magnetic interaction between double neutron stars (NSs) during their final inspiral within framework of unipolar inductor model. model, an electromotive force is induced on one NS to accelerate electrons ultra-relativistic speed instantaneously. We show coherent curvature radiation these moving along field lines in magnetosphere other responsible for observed FRB signal, is, characteristic emission frequency,...
X-ray flares are generally supposed to be produced by the later central engine activities, and may share similar physical origin with prompt emission of gamma-ray bursts (GRBs). In this paper, we have analyzed all significant from GRBs observed {\em Swift} April 2005 March 2015. The catalog contains 468 bright flares, including 200 redshifts. We obtain fitting results such as start time, peak duration, flux, fluence, luminosity, mean luminosity. luminosity decreases following a power-law...
The $\Lambda$CDM model successfully explains the majority of cosmological observations. However, is challenged by Hubble tension, a remarkable difference constant $H_0$ between measurements from local probe and prediction Planck cosmic microwave background observations under $ \Lambda$CDM model. So one urgently needs new distance indicators to test tension. Fast radio bursts (FRBs) are millisecond-duration pulses occurring at distances, which attractive probes. there thorny problem that...
Gamma-ray bursts (GRBs) are the most luminous explosions and can be detectable out to edge of Universe. It has long been thought they extend Hubble diagram very high redshifts. Several correlations between temporal or spectral properties GRB luminosities have proposed make GRBs cosmological tools. However, those cannot properly standardized. In this paper, we select a sample with X-ray plateau phases produced by electromagnetic dipole emissions from central new-born magnetars. A tight...
Fast radio bursts (FRBs) are cosmic sources emitting millisecond-duration bursts. Although several hundreds FRBs have been discovered, their physical nature and central engine remain unclear. The variations of Faraday rotation measure dispersion measure, due to local environment, crucial clues understanding nature. recent observations on the FRB 20201124A show a significant variation day time scale. Intriguingly, oscillation supports that contribution can change sign, which indicates...
Quasi-periodic eruptions (QPEs), which are a new kind of X-ray bursts with recurrence time several hours, have been detected from supermassive black holes (SMBHs) in galactic nuclei. Recently, the two QPEs discovered by \textit{eROSITA} show asymmetric light curves fast rise and slow decline. Current models cannot explain observational characteristics QPEs. Here we that can be generated Roche lobe overflows at each periapsis passage an evolved star orbiting SMBH. The properties companion...
The very high-energy afterglow in GRB 221009A, known as the “brightest of all time” (BOAT), has been thoroughly analyzed previous studies. In this paper, we conducted a statistical analysis waiting time behavior 172 TeV photons from BOAT observed by LHAASO-KM2A. following results were obtained: (I) distribution (WTD) these deviates exponential distribution. (II) exhibits characteristics resembling those self-organized critical system, such power-law and scale-invariance features WTD. times...
Abstract Fast radio bursts (FRBs) are signals that last milliseconds. They originate from cosmological distances and have relatively high dispersion measures (DMs), making them excellent distance indicators. However, the origins of FRB remain to be resolved. With its wide field view sensitivity, CHIME/FRB has discovered more than half all known FRBs. As FRBs located within or connected with their host galaxies, study progenitors is becoming important. In this work, we collect currently...
In this paper, we use two model-independent methods to standardize long gamma-ray bursts (GRBs) using the $E_{\rm iso}-E_{\rm p}$ correlation, where iso}$ is isotropic-equivalent energy and spectral peak energy. We update 42 GRBs try make constraint on cosmological parameters. The full sample contains 151 with redshifts from 0.0331 8.2. first method simultaneous fitting method. extrinsic scatter $σ_{\rm ext}$ taken into account assigned parameter iso}$. best-fitting values are...
Fast radio bursts (FRBs) are millisecond-duration signals occurring at cosmological distances. However the physical model of FRBs is mystery, many models have been proposed. Here we study frequency distributions peak flux, fluence, duration and waiting time for repeating FRB 121102. The cumulative fluence show power-law forms. distribution also shows distribution, consistent with a non-stationary Poisson process. These similar as those soft gamma repeaters (SGRs). We use statistical results...
We propose a new model-independent method to test the cosmic curvature by comparing proper distance and transverse comoving distance. Using measurements of Hubble parameter $H(z)$ angular diameter $d_A$, $\Omega_K$ is constrained be $-0.09\pm0.19$, which consistent with flat universe. also use Monte Carlo simulation validity efficiency, find that our can give reliable efficient constraint on curvature. Compared other methods testing curvature, avoid some drawbacks better constraint.
Superflares, as strong explosions on stars, have been well studied with the progress of space time-domain astronomy. In this work, we present study superflares solar-type stars using Transiting Exoplanet Survey Satellite ({\em{TESS}}) data. 13 sectors observations during first year {\em TESS} mission covered southern hemisphere sky, containing 25,734 stars. We verified 1,216 400 through automatic search and visual inspection 2-minute cadence Our result suggests a higher superflare frequency...
Gamma-ray bursts (GRBs) are the most violent explosions in Universe and can be used to explore properties of high-redshift universe. It is believed that long GRBs associated with deaths massive stars. So it possible use investigate star formation rate (SFR). In this paper, we Lynden-Bell's $c^-$ method study luminosity function \emph{Swift} without any assumptions. We find evolves redshift as $L(z)\propto g(z)=(1+z)^k$ $k=2.43_{-0.38}^{+0.41}$. After correcting evolution through...
Gamma-ray bursts (GRBs), as a possible probe to extend the Hubble diagram high redshifts, have attracted much attention recently. In this paper, we select two samples of GRBs that plateau phase in X-ray afterglow. One is short with phases dominated by magnetic dipole (MD) radiations. The other long gravitational-wave (GW) phases. These can be well standardized using correlation between luminosity $L_0$ and end time $t_b$. so-called circularity problem mitigated observational parameter data...