由中国科学院紫金山天文台牵头,联合国内外多家研究机构组成的研究团队,利用500 m口径球面射电望远镜中国天眼(FAST)取得重要突破——在国际上首次捕捉到重复快速射电暴(fost rodio bursts,FRB)的法拉第旋转量(rotation measure,RM)发...由中国科学院紫金山天文台牵头,联合国内外多家研究机构组成的研究团队,利用500 m口径球面射电望远镜中国天眼(FAST)取得重要突破——在国际上首次捕捉到重复快速射电暴(fost rodio bursts,FRB)的法拉第旋转量(rotation measure,RM)发生剧烈跃变并随后回落的详细演化过程。这一发现结果为“快速射电暴起源于双星系统”的假说提供了迄今为止最有力的观测证据。2026年1月16日,相关研究成果发表于《Science》。展开更多
We investigate the null tests of cosmic accelerated expansion by using the baryon acoustic oscillation(BAO)data measured by the dark energy spectroscopic instrument(DESI)and reconstruct the dimensionless Hubble parame...We investigate the null tests of cosmic accelerated expansion by using the baryon acoustic oscillation(BAO)data measured by the dark energy spectroscopic instrument(DESI)and reconstruct the dimensionless Hubble parameter E(z)from the DESI BAO Alcock-Paczynski(AP)data using Gaussian process to perform the null test.We find strong evidence of accelerated expansion from the DESI BAO AP data.By reconstructing the deceleration parameter q(z) from the DESI BAO AP data,we find that accelerated expansion persisted until z■0.7 with a 99.7%confidence level.Additionally,to provide insights into the Hubble tension problem,we propose combining the reconstructed E(z) with D_(H)/r_(d) data to derive a model-independent result r_(d)h=99.8±3.1 Mpc.This result is consistent with measurements from cosmic microwave background(CMB)anisotropies using the ΛCDM model.We also propose a model-independent method for reconstructing the comoving angular diameter distance D_(M)(z) from the distance modulus μ,using SNe Ia data and combining this result with DESI BAO data of D_(M)/r_(d) to constrain the value of r_(d).We find that the value of r_(d),derived from this model-independent method,is smaller than that obtained from CMB measurements,with a significant discrepancy of at least 4.17σ.All the conclusions drawn in this paper are independent of cosmological models and gravitational theories.展开更多
We search for the stochastic gravitational-wave background(SGWB) predicted by pre-Big-Bang(PBB) cosmology using data from the first three observing runs of Advanced LIGO and Advanced Virgo. PBB cosmology proposes an a...We search for the stochastic gravitational-wave background(SGWB) predicted by pre-Big-Bang(PBB) cosmology using data from the first three observing runs of Advanced LIGO and Advanced Virgo. PBB cosmology proposes an alternative to cosmic inflation where the Universe evolves from a weak-coupling, low-curvature state to the hot Big Bang through a high-curvature bounce phase, predicting a distinctive SGWB spectrum. We perform a Bayesian analysis of the cross-correlation data to constrain the model parameters characterizing the PBB spectrum. We find no evidence for a PBB-induced SGWB, with a Bayes factor of 0.03 between the PBB and noise-only model, strongly favoring the noise-only hypothesis. Our analysis establishes a lower bound β ≳-0.19 at 95% confidence level, which is compatible with the theoretical requirement β ≥ 0 for a smooth bounce transition. While we do not detect a signal,our constraints remain consistent with the basic theoretical framework of PBB cosmology,demonstrating the potential of gravitational-wave observations to test early Universe theories.展开更多
文摘由中国科学院紫金山天文台牵头,联合国内外多家研究机构组成的研究团队,利用500 m口径球面射电望远镜中国天眼(FAST)取得重要突破——在国际上首次捕捉到重复快速射电暴(fost rodio bursts,FRB)的法拉第旋转量(rotation measure,RM)发生剧烈跃变并随后回落的详细演化过程。这一发现结果为“快速射电暴起源于双星系统”的假说提供了迄今为止最有力的观测证据。2026年1月16日,相关研究成果发表于《Science》。
基金supported in part by the National Key Research and Development Program of China (Grant No.2020YFC2201504)the National Natural Science Foundation of China (Grant Nos.12588101 and 12535002)。
文摘We investigate the null tests of cosmic accelerated expansion by using the baryon acoustic oscillation(BAO)data measured by the dark energy spectroscopic instrument(DESI)and reconstruct the dimensionless Hubble parameter E(z)from the DESI BAO Alcock-Paczynski(AP)data using Gaussian process to perform the null test.We find strong evidence of accelerated expansion from the DESI BAO AP data.By reconstructing the deceleration parameter q(z) from the DESI BAO AP data,we find that accelerated expansion persisted until z■0.7 with a 99.7%confidence level.Additionally,to provide insights into the Hubble tension problem,we propose combining the reconstructed E(z) with D_(H)/r_(d) data to derive a model-independent result r_(d)h=99.8±3.1 Mpc.This result is consistent with measurements from cosmic microwave background(CMB)anisotropies using the ΛCDM model.We also propose a model-independent method for reconstructing the comoving angular diameter distance D_(M)(z) from the distance modulus μ,using SNe Ia data and combining this result with DESI BAO data of D_(M)/r_(d) to constrain the value of r_(d).We find that the value of r_(d),derived from this model-independent method,is smaller than that obtained from CMB measurements,with a significant discrepancy of at least 4.17σ.All the conclusions drawn in this paper are independent of cosmological models and gravitational theories.
基金supported by the National Natural Science Foundation of China(Grants No.12405055 and No.12347111)supported by the National Natural Science Foundation of China(Grant No.12505054 and 12433001)+5 种基金the China Postdoctoral Science Foundation(Grant No.2023M741148)the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20240458)supported by the National Natural Science Foundation of China under Grant No.12405056supported by the National Natural Science Foundation of China under Grant No.12405057the Natural Science Foundation of Hunan Province under Grant No.2025JJ40006the Innovative Research Group of Hunan Province under Grant No.2024JJ1006。
文摘We search for the stochastic gravitational-wave background(SGWB) predicted by pre-Big-Bang(PBB) cosmology using data from the first three observing runs of Advanced LIGO and Advanced Virgo. PBB cosmology proposes an alternative to cosmic inflation where the Universe evolves from a weak-coupling, low-curvature state to the hot Big Bang through a high-curvature bounce phase, predicting a distinctive SGWB spectrum. We perform a Bayesian analysis of the cross-correlation data to constrain the model parameters characterizing the PBB spectrum. We find no evidence for a PBB-induced SGWB, with a Bayes factor of 0.03 between the PBB and noise-only model, strongly favoring the noise-only hypothesis. Our analysis establishes a lower bound β ≳-0.19 at 95% confidence level, which is compatible with the theoretical requirement β ≥ 0 for a smooth bounce transition. While we do not detect a signal,our constraints remain consistent with the basic theoretical framework of PBB cosmology,demonstrating the potential of gravitational-wave observations to test early Universe theories.
