核心期刊
《天文和天体物理学研究》（英）是中国科学院国家天文台和中国天文学会主办的学术期刊，发表天文学和天体物理学领域高水平原创性的研究成果，旨在反映我国及整个亚洲和太平洋地区的天文学的进展
DOI：https://doi.org/10.1088/1674-4527/ae278a
提交时间： 2026-01-28
摘要：This study addresses the need for real-time sampling and transmission of wideband signals in radio astronomy, developing a comprehensive technical workflow from hardware implementation to firmware compilation. The system, based on the Xilinx ZCU111 Radio Frequency System on Chip (RFSoC) development board, incorporates hardware modifications and custom development using the CASPER open-source toolflow. We adopt a channelization method based on the Polyphase Filter Bank algorithm, provide the corresponding theoretical derivations, and implement the scheme on the CASPER open-source toolflow. The developed firmware enables channelization (16 channels, 128 MHz bandwidth) of ultra-wideband signals at a 4096 MHz sampling rate on RFSoC hardware. Deployed at the Nanshan 26 m radio telescope for L-band (964–1732 MHz) observations, the system successfully produced high signal-to-noise ratio pulsar profiles after processing with DSPSR software, validating the reliability of the channelization algorithm. These results confirm the feasibility of RFSoC-based architectures for wideband signal channelization, offering a practical pathway for future astronomical backends.
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1975
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DOI：https://doi.org/10.1088/1674-4527/ae25c6
提交时间： 2026-01-28
摘要：Building on our previous work, we apply a U-Net Variational Autoencoder (VAE) framework to denoise galaxy images from the James Webb Space Telescope and enhance morphological classification. This study focuses on galaxies observed up to redshift z ≈ 8, capturing them at early evolutionary stages where their faintness and structural complexity pose challenges for the traditional classification methods. By mitigating observational noise, our approach enables the identification of morphological features, particularly in distinguishing between disk and non-disk galaxy types. We evaluate the denoising performance using standard image quality metrics and demonstrate that the enhanced images lead to improved classification accuracy across multiple deep learning models. Our analysis of a sample of 292 galaxies up to z = 7.69 shows 83 galaxies classified as disk-like by the GCNN model with high confidence, and of those approximately 70%–80% are at redshifts greater than 3. These findings suggest that disk-like structures can be prevalent in the early universe. The results highlight the potential of VAE-based denoising as a robust pre-processing step for analyzing high-redshift galaxy populations in ongoing astronomical surveys.
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2097
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788
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0
DOI：https://doi.org/10.1088/1674-4527/ae2759
提交时间： 2026-01-28
摘要：Utilizing ALFALFA H I data, we investigate the relationship between specific star formation rate (sSFR) and halo spin across various star-forming galaxies. Our analysis reveals weak yet statistically significant positive correlation between sSFR and halo spin, irrespective of the galactic environment. This trend suggests that galaxies with higher spin parameters tend to host dynamically colder, gas-rich disks, sustaining elevated gas surface densities and prolonged star formation. These findings align with theoretical expectations of angular momentum-regulated gas accretion but highlight discrepancies with cosmological simulations, underscoring unresolved challenges in modeling baryonic feedback and star formation efficiency.
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2252
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878
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DOI：https://doi.org/10.1088/1674-4527/ae22c1
提交时间： 2026-01-28
摘要：The China-Argentina Radio Telescope (CART) has a diameter of 40 m, and eight working bands including L, S/X, C, Ku, K, Ka and Q. The S/X dual band cryogenic receivers and the dual beam Qband cryogenic receivers are among the first to be installed on CART starting from the testing phase. CART is a milestone joint-project between China and Argentina. It is located at the CESCO Observatory of the National University of San Juan of Argentina, and will be the largest single dish and Very Long Baseline Interferometry (VLBI) unit in Latin America. It is expected to have important synergies with LLAMA and the Argentine-German Geodetic Observatory, and will participate in and contribute to major international VLBI campaigns such as IVS, Square Killometre Array Very Long Baseline Interferometry and maybe also Atacama Large Millimeter/submillimeter Array in the future.
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2289
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926
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DOI：https://doi.org/10.1088/1674-4527/ae257e
提交时间： 2026-01-28
摘要：Deep space exploration has an extremely high requirement for beam pointing accuracy of the large reflector antenna fed by a beam waveguide system. Beam pointing error compensation is of great importance when the reflector is deformed by inevitable external loads. This study introduces an innovative compensation method for such large beam waveguide reflector antennas utilizing an adjustable ellipsoidal mirror in the beam waveguide system. Initially, the effect of the ellipsoidal mirror’s position deviation on the beam waveguide system’s outgoing focus is analyzed. Subsequently, an equivalent single reflector system for the dual reflector system of the beam waveguide reflector antenna is considered, and the derivation of the focus position deviation for the single reflector caused by the position deviation of the beam waveguide system’s outgoing focus is derived. Then, an electromechanical coupling model (EMCM) is formulated, incorporating both the reflector deformation and the ellipsoidal mirror’s position error. Finally, with the assumption of adjustability of the ellipsoidal mirror, the study explores the beam pointing error compensation problem based on the EMCM in scenarios of reflector deformation. This paper presents a case study on a 35 m aperture beam waveguide reflector antenna. The results demonstrate that the proposed EMCM achieves high accuracy in calculating the main beam direction, thereby validating the effectiveness of the proposed beam pointing error compensation method for large antennas.
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2143
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850
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0
DOI：https://doi.org/10.1088/1674-4527/ae21c7
提交时间： 2026-01-28
摘要：Digital backends are critical for modern radio interferometers, enabling wideband signal acquisition and flexible data processing. We present the design of a new RFSoC-based backend developed for the Central China Array (CARRY), currently under construction in Hubei, China. The system, built on the RFSoC-xczu47DR platform, supports wideband sampling of eight inputs at 1 GSPS with polyphase filter bank processing, channel equalization, and high-speed 100 GbE data transmission. Experimental results confirm reliable synchronization, high linearity, and stable spectral processing. This design provides CARRY with a high-performance, scalable, and cost-efficient reference architecture that can be extended to other radio interferometer arrays.
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2066
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837
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0
DOI：https://doi.org/10.1088/1674-4527/ae2103
提交时间： 2026-01-28
摘要：The spatial distribution and abundance of surface rocks on the Moon serve as critical determinants in landing site selection, mission planning, and scientific investigations. Due to the lack of optical and thermal infrared observations in permanently shadowed region, conventional remote sensing techniques encounter substantial challenges in directly retrieving rock-related information from these areas. Synthetic aperture radar (SAR) penetrates the lunar regolith, providing a robust and reliable means of acquiring subsurface information, particularly under rugged terrain or low-illumination conditions. This study proposes a rock abundance retrieval method by integrating Mini-RF SAR and Lunar Orbiter Laser Altimeter digital elevation model (DEM) data with a machine learning framework. Feature parameters are extracted from the SAR and the DEM data, and a random forest model optimized by the sparrow search algorithm is constructed to estimate rock abundance in lunar maria regions. Model training and validation in representative lunar maria areas demonstrate high predictive accuracy, with a coefficient of determination (R2) of 0.77 and a root mean square error of 0.004. The predicted rock abundance shows strong agreement with measurements from the Diviner thermal radiometer, supporting the model’s reliability. Furthermore, the trained model is applied to selected permanently shadowed regions near the lunar south pole, where optical remote sensing is unavailable due to the lack of sunlight. In these challenging environments, SAR and DEM data provide essential observational support for rock abundance estimation. This approach represents a viable pathway for investigating rock distribution in polar regions, and provides essential data and methodological insights for future lunar exploration, particularly regarding landing site safety and in-situ resource evaluation.
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2138
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814
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DOI：https://doi.org/10.1088/1674-4527/ae2222
提交时间： 2026-01-28
摘要：Helium white dwarfs (WDs) with masses less than 0.3 M⊙ are known as extremely low-mass WDs (ELM WDs), which cannot be produced by single stellar evolution in theory. Generally, these stars are believed to form through binary interactions. Recently, two ELM WDs in unusually wide orbits were reported, i.e., KIC 8145411 and HE 0430-2457. Their orbital separations are too wide to be produced by the binary evolution scenario. In this work, we study the formation of wide-orbit ELM WD binaries from hierarchical triple systems. In this scenario, an ELM WD is formed from the inner binary and subsequently forms a wide binary system with the third object. We find that the merger of an evolved star with a brown dwarf in the inner binary fails to produce single ELM WDs, but Type Ia supernovae (SNe Ia) explosions can successfully do so. Furthermore, we investigate the impact of the supernova explosion on the orbital distribution of the surviving binary and find that this channel may have a probability of reproducing the orbital parameters of HE 0430-2457, but fails to reproduce the observed features of KIC 8145411. This supports recent observational recalibrations suggesting that KIC 8145411 resides in a triple system rather than a binary.
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DOI：https://doi.org/10.1088/1674-4527/ae1f79
提交时间： 2026-01-28
摘要：Metals enhance the cooling efficiency of molecular clouds, promoting fragmentation. Consequently, increasing the metallicity may boost the formation of low-mass stars. Within the integrated galactic initial mass function (IGIMF) theory, this effect is empirically captured by a linear relation between the slope of the low-mass stellar IMF, α1, and the metal mass fraction, Z. This linear α1–Z relation has been calibrated up to ≈2 Z⊙, though higher metallicity environments are known to exist. We show that if the linear α1–Z relation extends to higher metallicities ([Z] ≳ 0.5), massive star formation is suppressed entirely. Alternatively, fragmentation efficiency may saturate beyond some metallicity threshold if gravitational collapse cascades rapidly enough. To model this behavior, we propose a logistic function describing the transition from metallicity-sensitive to metallicity-insensitive fragmentation regimes. We provide a user-friendly public code, pyIGIMF, which enables the instantaneous computation of the IGIMF theory with both linear and logistic α1–Zrelations.
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2028
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927
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0
DOI：https://doi.org/10.1088/1674-4527/ae1813
提交时间： 2026-01-28
摘要：The Wide Field Survey Telescope (WFST) is a 2.5 m optical telescope that has been in operation since 2023 September. Located on Saishiteng Mountain in Qinghai Province, the WFST benefits from exceptional atmospheric seeing conditions. However, the effect of the existing telescope dome on the astronomical seeing of WFST has not been characterized, which inevitably affects the imaging performance of the telescope. Two differential image motion monitors of the same configuration, one located in the dome and the other outside the dome, were used for seeing monitoring during the maintenance period of the WFST. Astronomical seeing measurements were conducted simultaneously inside and outside the dome under different dome ventilation configurations to quantify their effects. Statistical analysis of the seeing data collected under different ventilation conditions indicates that proper air convection in the dome can improve the in-dome seeing to reach near the level of the out-dome seeing and thereby improve the image quality of the WFST.
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