分类: 天文学 >> 天文仪器与技术 提交时间: 2024-06-06 合作期刊: 《天文技术与仪器(英文)》
摘要:With the growing significance of space weather forecasting, multi-layer magnetic and helioseismic telescopes are emerging as a key area of research. However, owing to the diverse operational processes and sophisticated hardware configurations of these devices, there is an urgent need for efficient autonomous observation capabilities. An autonomous Master Control System (MCS) can ensure efficient performance, data consistency, and stability, and the prototype presented here adopts a microservices architecture, breaking down the hardware into multiple subsystems and converting their functions into individual services. A central decision-making system leads the operations, supported by three auxiliary systems and three device control systems. Through inter-subsystem service calls, it achieves rapid imaging and spectroscopic monitoring. To verify system stability and observation efficiency, the system was tested on the Solar Full-disk Multi-layer Magnetograph. Experimental results verify this system can operate automatically for 4 consecutive months, acquire photospheric vector magnetic and Doppler velocity fields within a 15-minute interval, and measure chromospheric longitudinal magnetic and Doppler velocity fields in under 180 s. This ensures consistent and stable solar monitoring and serves as a practical methodological benchmark for the development of similar devices.
分类: 天文学 >> 天文仪器与技术 提交时间: 2024-04-18 合作期刊: 《天文技术与仪器(英文)》
摘要:Ancient China recorded a wealth of astronomical observations, notably distinguished by the inclusion of empirical measurements of stellar observations. However, determining the precise observational epochs for these datasets poses a formidable challenge. This study employs the generalized Hough transform methodology to analyze two distinct sets of observational data originating from the Song and Yuan dynasties, allowing accurate estimation of the epochs of these stellar observations. This research introduces a novel and systematic approach, offering a scholarly perspective for the analysis of additional datasets within the domain of ancient astronomical catalogs in future investigations.
分类: 天文学 >> 天文学 提交时间: 2023-12-29
摘要: Magnetars are neutron stars with extremely strong magnetic fields, frequently powering high-energy activity in X-rays. Pulsed radio emission following some X-ray outbursts have been detected, albeit its physical origin is unclear. It has long been speculated that the origin of magnetars' radio signals is different from those from canonical pulsars, although convincing evidence is still lacking. Five months after magnetar SGR 1935+2154's X-ray outburst and its associated Fast Radio Burst (FRB) 20200428, a radio pulsar phase was discovered. Here we report the discovery of X-ray spectral hardening associated with the emergence of periodic radio pulsations from SGR 1935+2154 and a detailed analysis of the properties of the radio pulses. The complex radio pulse morphology, which contains both narrow-band emission and frequency drifts, has not been seen before in other magnetars, but is similar to those of repeating FRBs - even though the luminosities are many orders of magnitude different. The observations suggest that radio emission originates from the outer magnetosphere of the magnetar, and the surface heating due to the bombardment of inward-going particles from the radio emission region is responsible for the observed X-ray spectral hardening.
分类: 天文学 >> 天文学 提交时间: 2023-12-18
摘要: The Five-hundred-meter Aperture Spherical radio Telescope (FAST) has discovered more than 650 new pulsars, which account for 20% of our known Galactic pulsar population. In this paper, we estimate the prospect of a pulsar survey with a radio telescope array to be planned -- the FAST Array (FASTA), consists of six FAST-type telescopes. Such a sensitive radio telescope array would be a powerful instrument in probing the pulsar population deep into our Galaxy as well as in nearby galaxies. We simulate the FASTA pulsar discovery prospects with different Galactic pulsar population models and instrumental parameter combinations. We find that FASTA could detect tens of thousands of canonical pulsars and well-over thousands of millisecond pulsars. We also estimate the potential yield if the FASTA is used to search for pulsars from the nearby spiral galaxy M31, and find that it would probably discover around a hundred new radio pulsars.
分类: 天文学 >> 天文学 提交时间: 2023-07-28
摘要: Cross-correlating the data on neutral hydrogen (H I) 21 cm intensity mapping with galaxy surveys is an effective method to extract astrophysical and cosmological information. In this work, we investigate the cross-correlation of MeerKAT single-dish mode H I intensity mapping and China Space Station Telescope (CSST) spectroscopic galaxy surveys. We simulate a survey area of 300 deg2 of MeerKAT and CSST surveys at z = 0.5 using Multi- Dark N-body simulation. The PCA algorithm is applied to remove the foregrounds of H I intensity mapping, and signal compensation is considered to solve the signal loss problem in H I-galaxy cross power spectrum caused by the foreground removal process. We find that from CSST galaxy auto and MeerKAT-CSST cross power spectra, the constraint accuracy of the parameter product H IbH IrH I,g can reach 1%, which is about one order of magnitude higher than the current results. After performing the full MeerKAT H I intensity mapping survey with 5000 deg2 survey area, the accuracy can be enhanced to can be a powerful tool to probe the cosmic H I property and the evolution of galaxies and the Universe.
分类: 天文学 >> 天文仪器与技术 分类: 光学 >> 仪器仪表、测量和计量 分类: 光学 >> 相干和统计光学 提交时间: 2023-06-28
摘要: Co-phase and co-focus detection is one of the key technologies for large-aperture segmented mirror telescopes. In this paper, a new edge sensor based on fringes of equal thickness is developed, which can detect each segment's relative piston, tilt, and tip errors from the interferograms. Based on the co-focus demand for many ground-based seeing limited segmented mirror telescopes, an edge sensor prototype based on such a principle is built and applied in the indoor segmented mirror experiment system in the lab. According to the co-focus requirement of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, many simulations and experiments are carried out for co-focus error detection of the segmented mirror system. Experiment results show that the co-focus accuracy is better than 0.02 rms, which can meet the co-focus requirements of most large or extremely large segmented mirror astronomical telescopes.
分类: 天文学 >> 天体物理学 提交时间: 2023-02-21
摘要: We present the analysis of seven microlensing planetary events with planet/host mass ratios q < 10^{-4}: KMT-2017-BLG-1194, KMT-2017-BLG-0428, KMT-2019-BLG-1806, KMT-2017-BLG-1003, KMT-2019-BLG-1367, OGLE-2017-BLG-1806, and KMT-2016-BLG-1105. They were identified by applying the Korea Microlensing Telescope Network (KMTNet) AnomalyFinder algorithm to 2016--2019 KMTNet events. A Bayesian analysis indicates that all the lens systems consist of a cold super-Earth orbiting an M or K dwarf. Together with 17 previously published and three that will be published elsewhere, AnomalyFinder has found a total of 27 planets that have solutions with q < 10^{-4} from 2016--2019 KMTNet events, which lays the foundation for the first statistical analysis of the planetary mass-ratio function based on KMTNet data. By reviewing the 27 planets, we find that the missing planetary caustics problem in the KMTNet planetary sample has been solved by AnomalyFinder. We also find a desert of high-magnification planetary signals (A≳65), and a follow-up project for KMTNet high-magnification events could detect at least two more q < 10^{-4} planets per year and form an independent statistical sample.