arXiv subjects

Jun-Jie Wei

Publications and source records attributed to Jun-Jie Wei.

At least 37 records · Page 2Linked to original sources

arXiv2025

Measuring the Time Variation of the Fine-structure Constant with Quasars Detected by LAMOST

The [O III] $λλ 4960,5008$ emission lines in the optical spectra of galaxies and quasars have been widely used to investigate the possible variation of the fine-structure constant $α$ over cosmic time. In this work, we utilize the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) quasar survey, for the first time, to measure the relative $α$ variation $Δα/α$ in time through the [O III] doublet method. From the LAMOST Data Release 9 quasar catalog, we refine a sample of 209 quasar spectra with strong and narrow [O III] emission lines over a redshift range of $0<z<0.8$. Analysis on all of the 209 spectra obtains $Δα/α= (0.5 \pm 3.7) \times 10^{-4}$, which suggests that there is no evidence of varying $α$ on the explored cosmological timescales. Assuming a linear variation, the mean rate of change in $Δα/α$ is limited to be $(-3.4 \pm 2.4)\times 10^{-13}$ $\mathrm{yr^{-1}}$ in the last 7.0 Gyr. While our LAMOST-based constraint on $Δα/α$ is not competitive with those of the Sloan Digital Sky Survey (SDSS) quasar observations, our analysis serves to corroborate the results of SDSS with another independent survey.

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arXiv2024

Stable Case BB/BC Mass Transfer to Form GW190425-like Massive Binary Neutron Star Mergers

On April 25th, 2019, the LIGO-Virgo Collaboration discovered a Gravitational-wave (GW) signal from a binary neutron star (BNS) merger, i.e., GW190425. Due to the inferred large total mass, the origin of GW190425 remains unclear. We perform detailed stellar structure and binary evolution calculations that take into account mass-loss, internal differential rotation, and tidal interactions between a He-rich star and a NS companion. We explore the parameter space of the initial binary properties, including initial NS and He-rich masses and initial orbital period. We find that the immediate post-common-envelope progenitor system, consisting of a primary $\sim2.0\,M_\odot$ ($\sim1.7\,M_\odot$) NS and a secondary He-rich star with an initial mass of $\sim3.0-5.5\,M_\odot$ ($\sim5.5-6.0\,M_\odot$) in a close binary with an initial period of $\sim0.08-0.5\,{\rm{days}}$ ($\sim 0.08-0.4\,{\rm{days}}$), that experiences stable Case BB/BC mass transfer (MT) during binary evolution, can reproduce the formation of GW190425-like BNS events. Our studies reveal that the secondary He-rich star of the GW190425's progenitor before its core collapse can be efficiently spun up through tidal interaction, finally remaining as a NS with rotational energy even reaching $\sim10^{52}\,{\rm{erg}}$, which is always much higher than the neutrino-driven energy of the supernova (SN) explosion. If the newborn secondary NS is a magnetar, we expect that GW190425 can be the remnant of a magnetar-driven SN, e.g., a magnetar-driven ultra-stripped SN, a superluminous SN, or a broad-line Type Ic SN. Our results show that GW190425 could be formed through the isolated binary evolution, which involves a stable Case BB/BC MT just after the common envelope phase. On top of that, we show the He-rich star can be tidally spun up, potentially forming a spinning magnetized NS (magnetar) during the second SN explosion.

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arXiv2024

Forecasts for Helium Reionization Detection with Fast Radio Bursts in the Era of Square Kilometre Array

The observed dispersion measures (DMs) of fast radio bursts (FRBs) are a good indicator of the amount of ionized material along the propagation paths. In this work, we present a forecast of He II reionization detection using the DM and redshift measurements of FRBs from the upcoming Square Kilometre Array (SKA). Assuming a model of the Universe in which He II reionization occurred at a specific redshift $z_{\rm re}$, we analyze what extent the signal-to-noise ratio ($\mathrm{S/N}$) for the detection of the amplitude of reionization can be achieved in the era of SKA. Using $10^{6}$ mock FRB data from a one-year observation of the second phase of SKA, we find that the $\mathrm{S/N}$ for detecting He II reionization can approach the $32-50σ$ level and the uncertainty on the reionization redshift can be constrained to be $σ(z_{\rm re})\approx 0.022-0.031$, depending on the assumed FRB redshift distribution. This is the first quantitative analysis on the detection significance of He II reionization in the SKA era. We also examine the influence of different fiducial $z_{\rm re}$ values, finding that this effect has a modest impact on the forecasts. Our results demonstrate the potentially remarkable capability of SKA-era FRBs in constraining the epoch of He II reionization.

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arXiv2024

The Dispersion Relation of Massive Photons in Plasma: A Comment on "Bounding the Photon Mass with Ultrawide Bandwidth Pulsar Timing Data and Dedispersed Pulses of Fast Radio Bursts"

The dispersion measures of fast radio bursts have been identified as a powerful tool for testing the zero-mass hypothesis of the photon. The classical approach treats the massive photon-induced and plasma-induced time delays as two separate phenomena. Recently, Wang et al. (2024) suggested that the joint influence of the nonzero photon mass and plasma effects should be considered, and proposed a revised time delay for massive photons propagating in a plasma medium, denoted as $Δt'_{m_γ} \propto ν^{-4}$, which departures from the classical dispersion relation ($\propto ν^{-2}$). Here we discuss the derivation presented by Wang et al. (2024) and show that the classical dispersion relation remains valid based on Proca equations.

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arXiv2024

A Comparative Analysis of Scale-invariant Phenomena in Repeating Fast Radio Bursts and Glitching Pulsars

The recent discoveries of a remarkable glitch/antiglitch accompanied by fast radio burst (FRB)-like bursts from the Galactic magnetar SGR J1935+2154 have revealed the physical connection between the two. In this work, we study the statistical properties of radio bursts from the hyperactive repeating source FRB 20201124A and of glitches from the pulsar PSR B1737--30. For FRB 20201124A, we confirm that the probability density functions of fluctuations of energy, peak flux, duration, and waiting time well follow the Tsallis q-Gaussian distribution. The derived q values from q-Gaussian distribution keep approximately steady for different temporal interval scales, which indicate that there is a common scale-invariant structure in repeating FRBs. Similar scale-invariant property can be found in PSR B1737--30's glitches, implying an underlying association between the origins of repeating FRBs and pulsar glitches. These statistical features can be well understood within the same physical framework of self-organized criticality systems.

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arXiv2024

Cosmology-independent Photon Mass Limits from Localized Fast Radio Bursts by using Artificial Neural Networks

A hypothetical photon mass, $m_γ$, can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed distance. The dispersion measure--redshift measurements of fast radio bursts (FRBs) have been widely used to constrain the rest mass of the photon. However, all current studies analyzed the effect of the frequency-dependent dispersion for massive photons in the standard $Λ$CDM cosmological context. In order to alleviate the circularity problem induced by the presumption of a specific cosmological model based on the fundamental postulate of the masslessness of photons, here we employ a new model-independent smoothing technique, Artificial Neural Network (ANN), to reconstruct the Hubble parameter $H(z)$ function from 34 cosmic-chronometer measurements. By combining observations of 32 well-localized FRBs and the $H(z)$ function reconstructed by ANN, we obtain an upper limit of $m_γ \le 3.5 \times 10^{-51}\;\rm{kg}$, or equivalently $m_γ \le 2.0 \times 10^{-15}\;\rm{eV/c^2}$ ($m_γ \le 6.5 \times 10^{-51}\;\rm{kg}$, or equivalently $m_γ \le 3.6 \times 10^{-15}\;\rm{eV/c^2}$) at the $1σ$ ($2σ$) confidence level. This is the first cosmology-independent photon mass limit derived from extragalactic sources.

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arXiv2024

First Digit Distributions of Gamma-Ray Bursts

The occurrence of the first significant digits from real world sources is usually not equally distributed, but is consistent with a logarithmic distribution instead, known as Benford's law. In this work, we perform a comprehensive investigation on the first digit distributions of the duration, fluence, and energy flux of gamma-ray bursts (GRBs) for the first time. For a complete GRB sample detected by the Fermi satellite, we find that the first digits of the duration and fluence adhere to Benford's law. However, the energy flux shows a significant departure from this law, which may be due to the fact that a considerable part of the energy flux measurements are restricted by lack of spectral information. Based on the conventional duration classification scheme, we also check if the durations and fluences of long and short GRBs (with duration $T_{90}>2$ s and $T_{90}\leq2$ s, respectively) obey Benford's law. We find that the fluences of both long and short GRBs still agree with the Benford distribution, but their durations do not follow Benford's law. Our results hint that the long--short GRB classification scheme does not directly represent the intrinsic physical classification scheme.

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arXiv2024

Extragalactic Test of General Relativity from Strong Gravitational Lensing by using Artificial Neural Networks

This study aims to test the validity of general relativity (GR) on kiloparsec scales by employing a newly compiled galaxy-scale strong gravitational lensing (SGL) sample. We utilize the distance sum rule within the Friedmann-Lema\^ıtre-Robertson-Walker metric to obtain cosmology-independent constraints on both the parameterized post-Newtonian parameter $γ_{\rm PPN}$ and the spatial curvature $Ω_{k}$, which overcomes the circularity problem induced by the presumption of a cosmological model grounded in GR. To calibrate the distances in the SGL systems, we introduce a novel nonparametric approach, Artificial Neural Network (ANN), to reconstruct a smooth distance--redshift relation from the Pantheon+ sample of type Ia supernovae. Our results show that $γ_{\rm PPN}=1.16_{-0.12}^{+0.15}$ and $Ω_k=0.89_{-1.00}^{+1.97}$, indicating a spatially flat universe with the conservation of GR (i.e., $Ω_k=0$ and $γ_{\rm PPN}=1$) is basically supported within $1σ$ confidence level. Assuming a zero spatial curvature, we find $γ_{\rm PPN}=1.09_{-0.10}^{+0.11}$, representing an agreement with the prediction of 1 from GR to a 9.6\% precision. If we instead assume GR holds (i.e., $γ_{\rm PPN}=1$), the curvature parameter constraint can be further improved to be $Ω_k=0.11_{-0.47}^{+0.78}$. These resulting constraints demonstrate the effectiveness of our method in testing GR on galactic scales by combining observations of strong lensing and the distance--redshift relation reconstructed by ANN.

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arXiv2023

The Hubble Tension Survey: A Statistical Analysis of the 2012-2022 Measurements

In order to investigate the potential Hubble tension, we compile a catalogue of 216 measurements of the Hubble--Lemaître constant $H_0$ between 2012 and 2022, which includes 109 model-independent measurements and 107 $Λ$CDM model-based measurements. Statistical analyses of these measurements show that the deviations of the results with respect to the average $H_0$ are far larger than expected from their error bars if they follow a Gaussian distribution. We find that $xσ$ deviation is indeed equivalent in a Gaussian distribution to $x_{\rm eq}σ$ deviation in the frequency of values, where $x_{\rm eq}=0.72x^{0.88}$. Hence, a tension of 5$σ$, estimated between the Cepheid-calibrated type Ia supernovae and cosmic microwave background (CMB) data, is indeed a 3$σ$ tension in equivalent terms of a Gaussian distribution of frequencies. However, this recalibration should be independent of the data whose tension we want to test. If we adopt the previous analysis of data of 1976-2019, the equivalent tension is reduced to $2.25σ$. Covariance terms due to correlations of measurements do not significantly change the results. Nonetheless, the separation of the data into two blocks with $H_0<71$ and $H_0\ge 71$ km s$^{-1}$ Mpc$^{-1}$ finds compatibility with a Gaussian distribution for each of them without removing any outlier. These statistical results indicate that the underestimation of error bars for $H_0$ remains prevalent over the past decade, dominated by systematic errors in the methodologies of CMB and local distance ladder analyses.

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arXiv2023

Revisiting constraints on the photon rest mass with cosmological fast radio bursts

Fast radio bursts (FRBs) have been suggested as an excellent celestial laboratory for testing the zero-mass hypothesis of the photon. In this work, we use the dispersion measure (DM)--redshift measurements of 23 localized FRBs to revisit the photon rest mass $m_γ$. As an improvement over previous studies, here we take into account the more realistic probability distributions of DMs contributed by the FRB host galaxy and intergalactic medium (IGM) from the IllustrisTNG simulation. To better account for the systematic uncertainty induced by the choices of priors of cosmological parameters, we also combine the FRB data with the cosmic microwave background data, the baryon acoustic oscillation data, and type Ia supernova data to constrain the cosmological parameters and $m_γ$ simultaneously. We derive a new upper limit of $m_γ\le3.8\times 10^{-51}\;\rm{kg}$, or equivalently $m_γ\le2.1 \times 10^{-15} \, \rm{eV/c^2}$ ($m_γ \le 7.2 \times 10^{-51} \, \rm{kg}$, or equivalently $m_γ\le4.0 \times 10^{-15} \, \rm{eV/c^2}$) at $1σ$ ($2σ$) confidence level. Meanwhile, our analysis can also lead to a reasonable estimation for the IGM baryon fraction $f_{\rm IGM}=0.873^{+0.061}_{-0.050}$. With the number increment of localized FRBs, the constraints on both $m_γ$ and $f_{\rm IGM}$ will be further improved. A caveat of constraining $m_γ$ within the context of the standard $Λ$CDM cosmological model is also discussed.

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arXiv2023

Investigating Cosmological Models and the Hubble Tension using Localized Fast Radio Bursts

We use the dispersion measure (DM) and redshift measurements of 24 localized fast radio bursts (FRBs) to compare cosmological models and investigate the Hubble tension. Setting a flat prior on the DM contribution from the Milky Way's halo, $\mathrm{DM_{halo}^{MW}}\in[5,\;80]\;\mathrm{pc\;cm^{-3}}$, the best fit for flat $Λ$CDM is obtained with a Hubble constant $H_0=95.8^{+7.8}_{-9.2}\;\mathrm{km\;s^{-1}\;Mpc^{-1}}$ and a median matter density $Ω_{\mathrm{m}}\approx0.66$. The best fit for the $R_{\mathrm{h}}=ct$ universe is realized with $H_0=94.2^{+5.6}_{-6.2}\;\mathrm{km\;s^{-1}\;Mpc^{-1}}$. We emphasize that the $H_0$ measurement depends sensitively on the $\mathrm{DM_{halo}^{MW}}$ prior. Since flat $Λ$CDM has one more free parameter, $R_{\mathrm{h}}=ct$ is favored by the Bayesian Information Criterion (BIC) with a likelihood of $\sim73\%$ versus $\sim27\%$. Through simulations, we find that if the real cosmology is $Λ$CDM, a sample of $\sim1,150$ FRBs in the redshift range $0<z<3$ would be sufficient to rule out $R_{\mathrm{h}}=ct$ at a $3σ$ confidence level, while $\sim550$ FRBs would be necessary to rule out $Λ$CDM if the real cosmology is instead $R_{\mathrm{h}}=ct$. The required sample sizes are different, reflecting the fact that the BIC imposes a severe penalty on the model with more free parameters. We further adopt a straightforward method of deriving an upper limit to $H_{0}$, without needing to consider the poorly known probability distribution of the DM contributed by the host galaxy. The theoretical DM contribution from the intergalactic medium ($\mathrm{DM_{IGM}}$) at any $z$ is proportional to $H_0$. Thus, requiring the extragalactic $\mathrm{DM_{ext}}$ to be larger than $\mathrm{DM_{IGM}}$ delimits $H_0$ to the upside. Assuming flat $Λ$CDM, we have $H_0<89.0\;\mathrm{km\;s^{-1}\;Mpc^{-1}}$ at a 95\% confidence level.

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arXiv2023

Model-Independent Determination of $H_0$ and $Ω_{K,0}$ using Time-Delay Galaxy Lenses and Gamma-Ray Bursts

Combining the `time-delay distance' ($D_{Δt}$) measurements from galaxy lenses and other distance indicators provides model-independent determinations of the Hubble constant ($H_0$) and spatial curvature ($Ω_{K,0}$), only based on the validity of the Friedmann-Lemaître-Robertson-Walker (FLRW) metric and geometrical optics. To take the full merit of combining $D_{Δt}$ measurements in constraining $H_0$, we use gamma-ray burst (GRB) distances to extend the redshift coverage of lensing systems much higher than that of Type Ia Supernovae (SNe Ia) and even higher than quasars, whilst the general cosmography with a curvature component is implemented for the GRB distance parametrizations. Combining Lensing+GRB yields $H_0=71.5^{+4.4}_{-3.0}$~km s$^{-1}$Mpc$^{-1}$ and $Ω_{K,0} = -0.07^{+0.13}_{-0.06}$ (1$σ$). A flat-universe prior gives slightly an improved $H_0 = 70.9^{+4.2}_{-2.9}$~km s$^{-1}$Mpc$^{-1}$. When combining Lensing+GRB+SN Ia, the error bar $ΔH_0$ falls by 25\%, whereas $Ω_{K,0}$ is not improved due to the degeneracy between SN Ia absolute magnitude, $M_B$, and $H_0$ along with the mismatch between the SN Ia and GRB Hubble diagrams at $z\gtrsim 1.4$. Future increment of GRB observations can help to moderately eliminate the $M_B-H_0$ degeneracy in SN Ia distances and ameliorate the restrictions on cosmographic parameters along with $Ω_{K,0}$ when combining Lensing+SN Ia+GRB. We conclude that there is no evidence of significant deviation from a (an) flat (accelerating) universe and $H_0$ is currently determined at 3\% precision. The measurements show great potential to arbitrate the $H_0$ tension between the local distance ladder and cosmic microwave background measurements and provide a relevant consistency test of the FLRW metric.

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arXiv2023

An 8.0\% Determination of the Baryon Fraction in the Intergalactic Medium from Localized Fast Radio Bursts

The dispersion measure (DM)--redshift relation of fast radio bursts (FRBs) has been proposed as a potential new tool for probing intergalactic medium (IGM) and for studying cosmology. However, the poor knowledge of the baryon fraction in the IGM ($f_{\mathrm{IGM}}$) and its degeneracy with cosmological parameters impose restrictions on the cosmological applications of FRBs. Furthermore, DMs contributed by the IGM ($\mathrm{DM_{IGM}}$) and host galaxy ($\mathrm{DM_{host}}$), important cosmological quantities, cannot be exactly extracted from observations, which would bring uncontrolled systematic uncertainties in FRB cosmology. In this work, we use seventeen localized FRBs to constrain $f_{\mathrm{IGM}}$ and its possible redshift evolution. Other cosmological probes such as type Ia supernovae, baryon acoustic oscillations, and cosmic microwave background radiation are combined to break parameter degeneracy. Taking into account the probability distributions of $\mathrm{DM_{IGM}}$ and $\mathrm{DM_{host}}$ derived from the the IllustrisTNG simulation, we obtain a robust measurement of $f_{\mathrm{IGM}}=0.927\pm0.075$, representing a precision of 8.0\%. We find that there is no strong evidence for the redshift dependence of $f_{\mathrm{IGM}}$ at the current observational data level. The rapid progress in localizing FRBs will significantly improve the constraints on $f_{\mathrm{IGM}}$.

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arXiv2023

Scale invariance in X-ray flares of gamma-ray bursts

X-ray flares are generally believed to be produced by the reactivation of the central engine, and may have the same energy dissipation mechanism as the prompt emission of gamma-ray bursts (GRBs). X-ray flares can therefore provide important clues to understanding the nature of the central engines of GRBs. In this work, we study for the first time the physical connection between differential size and return distributions of X-ray flares of GRBs with known redshifts. We find that the differential distributions of duration, energy, and waiting time can be well fitted by a power-law function. In particular, the distributions for the differences of durations, energies, and waiting times at different times (i.e., the return distributions) well follow a $q$-Gaussian form. The $q$ values in the $q$-Gaussian distributions remain nearly steady for different temporal interval scales, implying a scale-invariant structure of GRB X-ray flares. Moreover, we verify that the $q$ parameters are related to the power-law indices $α$ of the differential size distributions, characterized as $q=(α+2)/α$. These statistical features can be well explained within the physical framework of a self-organizing criticality system.

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arXiv2022

Bounding the Photon Mass with the Dedispersed Pulses of the Crab Pulsar and FRB 180916B

Tight limits on the photon mass have been set through analyzing the arrival time differences of photons with different frequencies originating from the same astrophysical source. However, all these constraints have relied on using the first-order Taylor expansion of the dispersion due to a nonzero photon mass. In this work, we present an analysis of the nonzero photon mass dispersion with the second-order derivative of Taylor series. If the arrival time delay corrected for all known effects (including the first-order delay time due to the plasma and photon mass effects) is assumed to be dominated by the second-order term of the nonzero photon mass dispersion, a conservative upper limit on the photon mass can be estimated. Here we show that the dedispersed pulses with the second-order time delays from the Crab pulsar and the fast radio burst FRB 180916B pose strict limits on the photon mass, i.e., $m_{γ,2} \leq5.7\times10^{-46}\;{\rm kg}\simeq3.2\times10^{-10}\; {\rm eV}/c^{2}$ and $m_{γ,2} \leq6.0\times10^{-47}\;{\rm kg}\simeq3.4\times10^{-11}\; {\rm eV}/c^{2}$, respectively. This is the first time to study the possible second-order photon mass effect.

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arXiv2022

Model selection using time-delay lenses

The sample of time-delay gravitational lenses appropriate for studying the geometry of the Universe continues to grow as dedicated campaigns, such as the Dark Energy Survey, the VST ATLAS survey, and the Large Synoptic Survey Telescope, complete their census of high-redshift sources. This catalog now includes hundreds of strong lensing systems, at least 31 of which have reasonably accurate time delay measurements. In this paper, we use them to compare the predictions of two competing Friedmann-Lemaitre-Robertson-Walker models: flat LCDM, characterized by two adjustable parameters (H_0 and Omega_m), and the R_h=ct universe (with H_0 as the single free variable). Over the past decade, the latter has accounted for the data better than the standard model, most recently the emergence of well-formed galaxies discovered by JWST at cosmic dawn. Here we show that the current sample of time-delay lenses favours R_h=ct with a likelihood of ~84% versus ~16% for the standard model. This level of accuracy will greatly improve as the ongoing surveys uncover many thousands additional lens systems over the next several years.

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arXiv2022

Exploring Anisotropic Lorentz Invariance Violation from the Spectral-Lag Transitions of Gamma-Ray Bursts

The observed spectral lags of gamma-ray bursts (GRBs) have been widely used to explore possible violations of Lorentz invariance. However, these studies were generally performed by concentrating on the rough time lag of a single highest-energy photon and ignoring the intrinsic time lag at the source. A new way to test nonbirefringent Lorentz-violating effects has been proposed by analyzing the multi-photon spectral-lag behavior of a GRB that displays a positive-to-negative transition. This method gives both a plausible description of the intrinsic energy-dependent time lag and comparatively robust constraints on Lorentz-violating effects. In this work, we conduct a systematic search for Lorentz-violating photon dispersion from the spectral-lag transition features of 32 GRBs. By fitting the spectral-lag data of these 32 GRBs, we place constraints on a variety of isotropic and anisotropic Lorentz-violating coefficients with mass dimension $d=6$ and $8$. While our dispersion constraints are not competitive with existing bounds, they have the promise to complement the full coefficient space.

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arXiv2022

Searching for Lorentz-violating Signatures from Astrophysical Photon Observations

As a basic symmetry of Einstein's theory of special relativity, Lorentz invariance has withstood very strict tests. But there are still motivations for such tests. Firstly, many theories of quantum gravity suggest violations of Lorentz invariance at the Planck energy scale. Secondly, even minute deviations from Lorentz symmetry can accumulate as particle travel across large distances, leading to detectable effects at attainable energies. Thanks to their long baselines and high-energy emission, astrophysical observations provide sensitive tests of Lorentz invariance in the photon sector. In this paper, I briefly introduce astrophysical methods that we adopted to search for Lorentz-violating signatures, including vacuum dispersion and vacuum birefringence.

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