本页经 2 次补录 · ·
推翻了恒星级黑洞喷流相对论性较弱的长期认知，为跨质量尺度统一理解黑洞喷流机制提供了关键观测证据。
对银河系X射线双星4U 1543−47单次爆发期间两次喷流抛射的射电干涉测量显示，其初始洛伦兹因子可能约为8，95%置信度下最小为4.6。
论文通过射电干涉测量直接测得恒星级黑洞喷流的高洛伦兹因子，直接否定了该领域长期存在的“恒星级黑洞喷流相对论性较弱”的假设，符合实质改变领域级认识的重大进展标准，保留为 headline。
ADS 2026NatCo..17.6477Z 4U 1543−47 未来爆发中的喷流洛伦兹因子测量
ADS 2026NatCo..17.6477Z 其他恒星级黑洞X射线双星的喷流洛伦兹因子测量
恒星级黑洞喷流与超大质量黑洞喷流同样相对论性
Relativistic jets from supermassive black holes in active galactic nuclei are amongst the most powerful phenomena in the universe. Similar jets from stellar-mass black holes offer a chance to study the phenomena on accessible observation time scales. However, such comparative studies across black hole masses and time scales remain hampered by the long-standing perception that stellar-mass black hole jets are in a less relativistic regime. Here, we show the detection of two distinct, relativistic jet ejections from the Galactic black hole X-ray binary 4U 1543−47 during a single outburst, with radio interferometry monitoring observations. Our measurements reveal a likely Lorentz factor of approximately 8 and a minimum of 4.6 at launch with 95% confidence, demonstrating that stellar-mass black holes in X-ray binaries can launch jets as relativistic as those seen in active galactic nuclei.
展开 ▾直接测量到高洛伦兹因子（约8），打破恒星级黑洞喷流较弱的传统观念，为统一理解不同尺度黑洞喷流奠定基础。
过去的研究倾向于认为恒星级黑洞喷流的块体运动速度低于超大质量黑洞喷流。本工作通过对4U 1543-47的密集射电监测，首次在单次爆发中清晰检测到两个分离的相对论性喷射事件，获得喷流表观速度，推导出最小洛伦兹因子4.6，证明恒星级黑洞完全可以产生极端相对论性喷流。该结果意味着黑洞喷流的基本物理可能不依赖于黑洞质量，从而支持了喷流统一模型。未来，随着SKA等新一代射电望远镜的运行，更高时间分辨率和灵敏度的观测将能捕捉更多瞬变事件，进一步限制喷流加速区和成分，深化对吸积与喷流反馈过程的理解。
接收 2026-04-24 · 刊出 2026-05-15 · 收录 2026-07-28
GWTC-4.0：对宇宙膨胀速率及修正引力波传播的限制
We analyze data from 142 of the 218 gravitational-wave (GW) sources in the fourth LIGO─Virgo─KAGRA Collaboration (LVK) Gravitational-Wave Transient Catalog (GWTC-4.0) to estimate the Hubble constant H<SUB>0</SUB> jointly with the population properties of merging compact binaries. We measure the luminosity distance and redshifted masses of GW sources directly; in contrast, we infer GW source redshifts statistically through (i) location of features in the compact object mass spectrum and merger rate evolution, and (ii) identifying potential host galaxies in the GW localization volume. Probing the relationship between source luminosity distances and redshifts obtained in this way yields constraints on cosmological parameters. We also constrain parameterized deviations from general relativity that affect GW propagation, specifically those modifying the dependence of a GW signal on the source luminosity distance. Assuming our fiducial model for the source-frame mass distribution and using GW candidates detected up to the end of the fourth observing run (O4a), together with the GLADE+ all-sky galaxy catalog, we estimate <inline-formula> <mml:math><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>75</mml:mn><mml:mo>.</mml:mo><mml:msubsup><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>9.1</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>12.8</mml:mn></mml:mrow></mml:msubsup><mml:mspace></mml:mspace><mml:mo>(</mml:mo><mml:mn>75</mml:mn><mml:mo>.</mml:mo><mml:msubsup><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>13.3</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>24.5</mml:mn></mml:mrow></mml:msubsup><mml:mo>)</mml:mo><mml:mspace></mml:mspace><mml:msup><mml:mrow><mml:mspace></mml:mspace><mml:mtext>km s</mml:mtext><mml:mspace></mml:mspace></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup><mml:mspace></mml:mspace><mml:msup><mml:mrow><mml:mspace></mml:mspace><mml:mtext>Mpc</mml:mtext><mml:mspace></mml:mspace></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:math> </inline-formula>. This value is reported as a median with 68.3% (90%) symmetric credible interval, and includes combination with the H<SUB>0</SUB> measurement from GW170817 and its electromagnetic counterpart. Using a parameterization of modified GW propagation in terms of the magnitude parameter Ξ<SUB>0</SUB>, we estimate <inline-formula> <mml:math><mml:msub><mml:mrow><mml:mi>Ξ</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:mo>.</mml:mo><mml:msubsup><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>0.4</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>1.0</mml:mn></mml:mrow></mml:msubsup><mml:mspace></mml:mspace><mml:mo>(</mml:mo><mml:mn>1</mml:mn><mml:mo>.</mml:mo><mml:msubsup><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>0.6</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>2.8</mml:mn></mml:mrow></mml:msubsup><mml:mo>)</mml:mo></mml:math> </inline-formula>, where Ξ<SUB>0</SUB> = 1 recovers the behavior of general relativity.
展开 ▾首次基于GWTC-4.0大量暗哑警报，不依赖电磁对应体（除GW170817外），通过质量谱特征和宿主星系统计推断红移，同时约束哈勃常数与传播修正参数Ξ0。
这项研究延续了从双中子星并合GW170817及电磁对应体获得独立哈勃常数测量的思路，并将统计方法扩展至暗哑警报。此前GWTC-3已尝试利用引力波源质量分布特征与星系目录联合推断红移；本文进一步在GWTC-4.0的142个事件上，结合O4a数据与GLADE+全天空星系目录，同时约束哈勃常数与修正引力波传播参数。结果表明H0中位值约75 km/s/Mpc，且与广义相对论一致的Ξ0=1落在置信区间内。未来随着观测时间积累、事件数增加以及第三代探测器投入使用，这种不依赖电磁对应体的暗哑警报宇宙学方法有望大幅提高哈勃常数的测量精度，并为检验修改引力理论提供更强限制。
接收 2026-04-24 · 刊出 2026-08-05 · 收录 2026-08-20
We present a study of short-timescale <inline-formula><tex-math>$340$</tex-math></inline-formula> GHz flux-density variability of Sagittarius A<inline-formula><tex-math>$^{*}$</tex-math></inline-formula> (Sgr A<inline-formula><tex-math>$^{*}$</tex-math></inline-formula>) using ALMA Cycle 3 observations. Careful self-calibration enabled snapshot imaging with <inline-formula><tex-math>$10$</tex-math></inline-formula> s integrations, achieving an effective image-domain SNR exceeding <inline-formula><tex-math>$10^{8}$</tex-math></inline-formula> and allowing high-cadence monitoring of major Galactic Center sources. To suppress common-mode atmospheric and instrumental fluctuations, we measured the flux of Sgr A<inline-formula><tex-math>$^{*}$</tex-math></inline-formula> relative to multiple non-variable sources within the same field of view. We further quantified and corrected apparent variability induced by time-dependent u─v coverage and the associated PSF changes by performing imaging simulations with a static input model. These procedures isolate the intrinsic intensity variations of Sgr A<inline-formula><tex-math>$^{*}$</tex-math></inline-formula> with substantially reduced non-source contamination. We searched for characteristic variability timescales over <inline-formula><tex-math>$20\, \rm{s}\lt \tau \le T_{\mathrm{obs}}/3$</tex-math></inline-formula> using structure-function analysis, the Lomb─Scargle method, and state-space-model-based autoregressive spectral analysis. No dominant narrow periodic component is detected. Instead, we identify a distinct short-timescale, flat (white-noise-like) regime at <inline-formula><tex-math>$\tau \lesssim 2.3$</tex-math></inline-formula>─<inline-formula><tex-math>$6.3\,\rm{min}$</tex-math></inline-formula>, followed by red-noise-like behavior at longer timescales. The short-timescale white-noise regime appears in both active and quiescent phases, indicating statistically independent fluctuations on these timescales. We interpret the upper boundary of the white-noise regime as an empirical transition timescale, below which fluctuations remain effectively decorrelated and above which temporally correlated variability emerges. Existing theoretical and numerical studies of black-hole accretion flows have not, to our knowledge, explicitly predicted a physically white power spectrum at the shortest timescales, although they do not necessarily exclude such behavior. Reported results have more commonly shown red-noise-like or broken-power-law variability, and the physical origin of the flat short-timescale component identified here therefore remains uncertain.
展开 ▾人马座A*亚毫米通量的短时标变化 · 利用ALMA数据研究Sgr A*在340 GHz的短时标变异性，发现约2.3-6.3分钟以下的白色噪声平坦区，之上为红噪声行为，未检测到显著周期成分。
预印本 2026-04-24 · 刊出 2026-05-28 · 收录 2026-08-20
We propose a quantum-enhanced sensing scheme for the detection of wavelike dark matter and high-frequency gravitational waves using two-dimensional ion crystals in a Penning trap. The protocol employs spin-motion squeezed states to improve the signal-to-noise ratio and enable a super-Heisenberg scaling with respect to the number of ions over a broad parameter range. We analyze the sensitivity of the protocol to representative wavelike dark matter candidates, including the axionlike particle and the dark photon, as well as to high-frequency gravitational waves, taking into account the decoherence and dephasing of the ion spins. Our results indicate that two-dimensional ion crystals and this new protocol provide a promising platform for probing previously unexplored parameter space in searches for light dark matter and high-frequency gravitational waves.
展开 ▾用于暗物质和高频引力波搜索的超海森堡协议 · 提出利用潘宁阱中二维离子晶体和自旋运动压缩态，实现超海森堡标度灵敏探测波状暗物质和高频引力波。
预印本 2026-04-24 · 刊出 2026-08-12 · 收录 2026-08-22