Context. White-light flares (WLFs) are crucial for understanding the energy transport and heating processes in the lower solar atmosphere. Systematic studies are highly necessary. However, most WLFs are very weak and difficult to detect. Aims. To address this, we propose a new method of detecting WLFs. Methods. Through the observations of SDO/HMI, the light curve of each pixel in the flaring region can be obtained. By subtracting the slowly varying background, we obtained a series of rapidly varying radiative pulses. Pixels for which radiative pulses during flares significantly exceed those occurring before and after the flare were identified as WL emission regions. Results. We applied our method to the detection of the X2.2 flare on September 6, 2017 and validated the method. We found that the WL emission in this flare exhibits two phases, and that different regions show distinct WL emission properties. We also detected the WL emission in all the flares (1 X-class, 2 M-class, and 20 C-class) occurred in active region NOAA 12887. It was found that 15 of the 23 flares are WLFs (1 X-class, 2 M-class, and 12 C-class). The occurrence rate of WLFs in this active region is ∼65%. Surprisingly, the occurrence rate of WLFs in C-class flares even reaches up to 60%. It should be noted that most of these C-class WLFs are below C5.0. In addition, a C1.0 WLF was identified; this is the lowest GOES-class event with confirmed WL emission to date. Conclusions. These results demonstrate that WL emission is ubiquitous in most flares, even down to C-class events.

Jets, as an essential manifestation of the release of the free magnetic energy, are ubiquitous in the solar atmosphere. We present a comprehensive analysis of a multithermal blowout jet that occurred in active region AR 13102 on 2022 September 20, using observations from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly, SDO/Helioseismic and Magnetic Imager (HMI), Interface Region Imaging Spectrograph, and Solar Upper Transition Region Imager. The jet is initiated by compact brightenings at its footpoints and exhibits a curtain-like spire with apparent rotational and weak lateral whipping motions. Time-distance analysis reveals a projected axial velocity similar to 300 km s-1 and a rotational speed similar to 30 km s-1. Differential emission measure analysis shows that the jet plasma spans a broad temperature range, with hot (greater than or similar to 10 MK) plasma concentrated near the flare loops and jet base and cooler components extending along the spire. Using the derived kinetic and thermal properties, we conclude that there is an equipartition between the jet's kinetic energy (5.4 +/- 2.4) & times; 1020 J and thermal energy (7.0 +/- 3.6) & times; 1020 J. HMI vector magnetograms and nonlinear force-free field extrapolations reveal that the jet originates from a compact mixed-polarity region at the edge of the active region, where flux emergence and cancellation, a low-lying twisted magnetic flux rope with a maximum twist number of similar to 2.1, and a surrounding high-Q quasi-separatrix layer are present. The observed decrease in twist after the eruption, together with the jet's untwisting, indicates that the jet is driven by the eruption and the reconnection of the twisted flux rope, converting magnetic free energy into plasma heating and bulk motion. Our results highlight the importance of small-scale flux rope eruptions in driving blowout jets and releasing twist through magnetic reconnection and untwisting motions.

Ground-based observation is important for solar physics research. However, cloud cover between the Sun and the Earth contaminates and degrades the quality of the acquired solar observation images obtained, thereby affecting the research on solar physics. Therefore, these images need to be screened and categorized. Previously, traditional methods and manual screening were capable of handling this task. However, with the advancement of technology, the observation equipment is now capable of collecting data of terabyte scale. The existing methods are unable to handle the data obtained by the observation equipment efficiently, and thus are no longer applicable. We adopted an improved deep learning method based on U-Net, integrating attention mechanisms, convolutional neural networks and feature fusion mechanisms to solve the problem of cloud coverage assessment in full-disk solar images. We utilized a dataset comprising 4350 pieces of data captured by the Solar Full-disk Multi-layer Magnetograph (SFMM), selecting precision, recall, F1 score, and macro F1 score as evaluation metrics, and evaluated the performance of our model along with the comparative experimental models through five-fold cross-validation. The Macro-Precision of our model reaches 0.9782, the score of our model on Macro-F1 is 0.9782. These metric values demonstrate that our method achieves more accurate classification of ground-based observation data.

Quasi-periodic pulsations (QPPs) have been observed in a broad electromagnetic spectrum, encompassing radio, ultraviolet, white light, X-rays, and Gama-rays. Yet, flare-associated QPPs remain rarely detected in mid-infrared emission. Here, we explored dual-period QPPs in the mid-infrared waveband, hard X-rays (HXRs), and microwave emission during an X1.5 flare on 2024 December 30 (SOL2024-12-30T04:01). Flare QPPs with dual quasi-periods at about 8.5 s and 4.6 s were simultaneously detected in the AIMS 8-10 um, Fermi 26-50 keV, and HXI 20-50 keV wavebands during the impulsive phase. Imaging observations show that the flare emission sources in the mid-infrared, HXR, and white-light wavebands are spatially coincident. Mid-infrared emissions are primarily localized at the loop top and double footpoints, which are connected by a hot plasma loop. These observational features support intermittent and rapid energy release via oscillatory magnetic reconnection during the solar flare. Differential emission measure analysis confirms fast sausage waves in flaring loops, while the WST observation indicates a white-light flare. We localized the flare QPPs with double periods in mid-infrared, HXR, and microwave emissions during a white-light flare. The flare-associated QPPs may be attributed to a quasi-periodic regime of magnetic reconnection, with the double periods likely modulated by quasi-harmonics of sausage waves.

The chromosphere is a complex solar atmosphere that hosts a variety of transients and transports significant free energy to heat the corona. However, due to the limited sensitivity of polarization measurement and the influence of spectral line broadening, the basic magnetic field configuration in the chromosphere has not yet been fully revealed to correspond to the observed phenomena. In this work, we investigated the validity and application of the magnetic field inversion method for the H-beta 4861 A spectral line with non-local thermodynamic equilibrium (non-LTE) approximations. The formation height of the H beta line center in the chromosphere is 1100-1300 km ( log tau(500nm) = [-4.86, -5.00]) in quiet Sun (QS) and 300-410 km ( log tau(500nm) = [-2.41, -4.57]) in sunspots. We generated synthetic spectra by incorporating magnetic fields into semi-empirical Fontenla-Avrett-Loeser (FAL) models for QS and sunspots, and then performed inversions to obtain the magnetic fields, which were then compared with the magnetic fields in the models. In addition, we evaluated the accuracy of the magnetic fields obtained using the weak-field approximation (WFA) and the impact of using these WFA results as the initial guess model for non-LTE inversion on the final results. Our work validates the effectiveness of the inversion method for the measurement of line-of-sight (LOS) magnetic field components, which significantly improved the accuracy in both weak field (0-500 G) and strong field (>2000 G) regions, while maintaining accuracy in the intermediate field range of 500-2000 G. This demonstrates that the inversion techniques we employed are capable of resolving Zeeman-sensitive spectral lines in the chromosphere, which can be applied to the H-beta observational data from the new generation Solar Full-disk Multi-layer Magnetograph at GanYu Solar Station to provide full disk chromospheric magnetic field information.

Coronal waves, significant solar phenomena, act as diagnostic tools for scientists studying solar atmosphere properties. Here, we present a novel observation detailing how a coronal wave event, associated with an X5.0 class flare, influenced the properties of an adjacent coronal hole (CH) through interaction. The coronal wave was observed in both extreme-ultraviolet (EUV) observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and Ly α observations from the Solar Disk Imager on board the Advanced Space-based Solar Observatory. Utilizing the method of differential emission measure, we found that as the coronal wave passed through, the adjacent CH experienced an increase in temperature from 1.31 to 1.43 MK and a rise in density from ∼1.62 × 10 8 to 1.76 × 10 8 cm −3 within the rising period of ∼7 minutes. Subsequently, after the wave passed, the entire CH transitioned to a new state with a slight temperature increase and a 14% decrease in density, with more pronounced changes observed at the CH’s boundary. Taking into account the impacts of radiative loss and heat conduction, the coronal wave was estimated to provide an average energy of 2.2 × 10 8 erg cm −2 to the CH during the short rising period. This study highlights the identification of the coronal wave in both EUV and Ly α observations, shedding light on the significant energy input, particularly within the CH. These findings provide new insights into better understanding kinematics of fast coronal waves, energy transfer processes open versus closed magnetic topologies, and the possible acceleration of solar winds.

In this paper, we report the detection of the very-high-energy (VHE, 100 GeV < E < 100 TeV) and ultra-high-energy (UHE, E > 100 TeV) γ-ray emissions from the direction of the young star-forming region W43, observed by the Large High Altitude Air Shower Observation (LHAASO). The extended γ-ray source was detected with a significance of ∼16 σ by KM2A and ∼17 σ by WCDA, respectively. The angular extension of this γ-ray source is about 0.5 degrees, corresponding to a physical size of about 50 pc. We discuss the origin of the γ-ray emission and possible cosmic ray acceleration in the W43 region using multi-wavelength data. Our findings suggest that W43 is likely another young star cluster capable of accelerating cosmic rays (CRs) to at least several hundred TeV.

The year 2024 has witnessed a lot of solar activities, such as solar flares, solar proton events, and sunspots. As one of the most notable space-based facilities, ASO-S has collected a valuable data set of the Sun in 2024. Most of the data sets from ASO-S are open to worldwide scientists. It is necessary to release more information about the situation of ASO-S in the past year. The authors have presented the orbit evolution, and the telemetry parameters from platform and payloads; the preliminary products from HXI, FMG, and LST are also presented in the paper.

Solar observations in extreme ultraviolet (EUV) wavelengths are a crucial component of solar activity research and space weather forecasting. The Solar Upper Transition Region Imager (SUTRI) on the SATech-01 satellite is designed to take full-disk solar images in the Ne vii 46.5 nm spectral line (T = 0.5 MK). It was launched in 2022 and the science data were released on January 10, 2023. In this article, we describe the data preprocessing method employed to SUTRI data to eliminate inherent instrument effects and standardize the raw data to obtain scientific data. Alongside common data processing steps, our pipeline includes correcting for horizontal stripes from the CMOS imaging camera. As an experiment payload, SUTRI does not have an image stabilization system. Thus, a multi-step iterative algorithm has been developed to precisely align series of drifted images due to the limited pointing accuracy of the satellite platform. Our method may not be limited to SUTRI; it also serves as a reference for future solar EUV telescope data processing.

The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data recorded by the EDs and MDs are used to reconstruct primary information of cosmic-ray and gamma-ray showers. To ensure the reliability of the LHAASO-KM2A data, a three-level quality control system has been established. It is used to monitor the status of detector units, stability of reconstructed parameters and the performance of the array based on observations of the Crab Nebula and Moon shadow. This paper will introduce the control system and its application on the LHAASO-KM2A data collected from August 2021 to July 2023. During this period, the pointing and angular resolution of the array were stable. From the observations of the Moon shadow and Crab Nebula, the results achieved using the two methods are consistent with each other. For example, according to the observation of the Crab Nebula with KM2A at energies from 25 TeV to 100 TeV, the time averaged pointing errors are estimated to be -0.003 degrees +/- 0.005 degrees and 0.001 degrees +/- 0.006 degrees in the R.A. and Dec directions, respectively.

The primary objective of our research is to validate direct measurements of the solar magnetic field through calculating the splitting of polarized spectral lines. The data are collected by the Solar Magnetism and Activity Telescope (SMAT) located at the Huairou Solar Observing Station (HSOS). The number of sampling points of the spectral line profile was varied from 5 to 31. By fitting the profiles of left- and right-circularly polarized light intensities, we determined the spectral line splitting, and the error between the magnetic-field strength determined from this and the true value was less than 2

Objective The detection of the line-of-sight (LOS) velocity of coronal mass ejections (CMEs) is essential for understanding their origins and early propagation, and for predicting their arrival time at Earth. The true velocity and evolution of CMEs are crucial for studying the mechanisms of solar eruptions and space weather forecasting. However, the velocity obtained from imaging observations represents only the plane-of-sky (POS) component, not the true velocity vector. To obtain the true velocity, both the POS and LOS components are essential. Based on the Doppler effect, it is possible to measure the LOS velocity of CMEs using a Sun-as-a-star extreme ultraviolet (EUV) spectrograph with a spectral resolving power greater than 500. However, the spectral resolutions of existing instruments are insufficient to meet the detection requirements of CMEs LOS velocity. Therefore, to achieve a spectral resolving power of 500 for detecting the LOS velocity of CMEs, we propose a new detection scheme using a concave varied-line-spacing (VLS) grating and an sCMOS detector. We design and develop a prototype in the wavelength range of 18-30 nm, which achieves EUV spectra with spectral resolving powers greater than 700. Additionally, we propose a data processing method to obtain the one-dimensional spectrum by integrating the two-dimensional spectrum along the slit. This method can improve the signal-to-noise ratio and significantly reduce the downstream data volume, which is suitable for deep space exploration missions. Our investigation provides important support for the development of full-disk integrated spectrograph (FIS) for the solar polar-orbit observatory (SPO) and for detecting the LOS velocity of CMEs. Methods We first determine the requirements of the Sun-as-a-star EUV spectrograph based on scientific objectives. The field of view (FOV) of the spectrograph is configured to 34', covering most of the EUV radiance from both the solar disk. The wavelength range of 18-30 nm is selected to measure the LOS velocity of CMEs formed at typical temperatures. A spectral resolving power exceeding 500 is necessary to achieve an accurate measurement of the CMEs LOS velocity. These requirements are ensured in the optical design, structure design, and data processing. Second, we use a new detection scheme with a concave VLS grating and an sCMOS detector, which is designed as a grazing incidence optical structure referring to MEGS-A in SDO/EVE. We comprehensively consider the slit width, grating, and pixel resolution to ensure spectral resolution. Based on the meridian focusing condition of the concave grating and line dispersion, we select the grating with a larger curvature radius and variable line spacing to reduce aberration and improve spectral resolution. The detector, with a pixel size of 6.5 mu m, is the sCMOS detector validated by the solar upper transition region imager (SUTRI). The slit width is set to be 20 mu m according to the sampling theory and the magnification of the grating. We also use SHADOW VUI ray tracing software to calculate the spectral resolution and error range of the system. Then, we optimize the structure design and assembly methods. We rely on machining accuracy and high-precision turntables to ensure the accuracies of the distance from slit to grating and the incident angle in the air, and fine-tune the detector position through a flexible corrugated pipe in the vacuum environment. Using a narrow linewidth EUV light source, namely a hollow cathode lamp, helium gas can be ionized under high pressure to obtain EUV radiation. Finally, we propose a data processing method for the uneven and tilted spectra: 1) reducing the dark field of the superimposed images from multiple frames and performing spectral line identification; 2) identifying and correcting thermal and damaged pixels in the image using median filtering; 3) calculating the spectral tilt using cubic spline interpolation for sub-pixel translation; 4) integrating 2048 rows of spectra along the slit. Results and Discussions Based on the optical parameters of the grating and sCMOS d simulated spectral resolving powers of 772, 876, and 965 for 24.3, 25.63, and 30.37 nm, respectively (Fig. 2). We further design and develop a prototype for the Sun-as-a-star EUV spectrograph (Figs. 3 and 4), equipped with relevant gas injection systems, high-pressure molecular pumps, refrigeration equipment, etc., and finally obtain three ionization spectral lines of helium at He 1124.303 nm, He 1125.632 nm, and He 1130.378 nm (Fig. 5). The superimposed spectrum shows a significant improvement in the signal-to-noise ratio compared to the spectrum extracted from single row after correction by dark field (Fig. 6). We use Gaussian fitting on the corrected spectra and obtain spectral resolving powers of 745, 788, and 865 for the three spectral lines, respectively (Fig. 6, Table 3). These results indicate that the new detection scheme can achieve a high spectral resolving power of over 500, which meets the detection requirement for CMEs LOS velocity. Compared with existing Sun-as-a-star EUV spectrographs, we use a larger curvature radius, a longer slit, and a data processing method that improves the signal-to-noise ratio and reduces the amount of downstream data. It offers more comprehensive advantages in terms of luminous flux, spectral resolution, and data transmission (Table 4). Conclusions We propose a new scheme with high spectral resolution using concave VLS grating and sCMOS detector for the detection of CMEs LOS velocity. We complete simulation calculations, optics and structure design, actual spectral calibration, and the exploration of data processing method on orbit for the Sun-as-a-star EUV spectrograph. Using helium as the ionized gas, we obtain spectra of He 1124.303 nm, He 1125.632 nm, and He 1130.378 nm. We propose a data processing method for the measured spectra that involves reducing the dark field, identifying and correcting thermal and damaged pixels, and correcting spectral tilt. This method can integrate two-dimensional array data into one-dimensional spectral data, which can improve the signal-to-noise ratio without reducing spectral resolution and significantly decrease transferred data. Therefore, this method is highly suitable for data processing on orbit in deep space exploration missions. The spectral resolving powers of He 1124.303 nm, He 1125.632 nm, and He 1130.378 nm are 745, 788, and 865, respectively, which are three times higher than the similar instrument SDO/EVE. The research provides an important basis for the detection of CMEs LOS velocity and the development of the FIS equipped on the SPO in China.etector (Table 2), we obtain the

The infrared band contains rich opportunities for astronomical research, but due to the limitations of infrared technology, the development of infrared astronomy in China has been far from satisfactory for a long time,especially for solar observation.“Accurate Infrared Magnetic field Measurements of the Sun” project (AIMS) is a National Major Scientific Research Instrument Development Project (recommended by the Ministries) supported by the National Natural Science Foundation of China. It is aimed at improving the accuracy of magnetic field measurement by an order of magnitude, by measuring the “Zeeman splitting” directly. In addition, as AIMS is also the first equipment specifically designed for mid-to far-infrared solar observation in the world, we also hope to utilize AIMS to explore potential new scientific research opportunities in the vast infrared region. This article will briefly introduce the scientific objectives, the telescope, the scientific post-focus instruments, and finally summarize the commissioning observations of AIMS.

A 50 mm balloon-borne white-light coronagraph (BBWLC) to observe white-light solar corona over the altitude range from 1.08 R-circle dot to 1.50 R-circle dot has recently been indigenously developed by Yunnan Observatories in collaboration with Shandong University (in Weihai) and Changchun Institute of Optics, Fine Mechanics and Physics, which will significantly improve the ability of China to detect and measure the inner corona. On 2022 October 4, its first scientific flight took place at the Dachaidan area in Qinghai province of China. We briefly describe the BBWLC mission including its optical design, mechanical structure, pointing system, the first flight and results associated with the data processing approach. Preliminary analysis of the data shows that BBWLC imaged the K-corona with three streamer structures on the west limb of the Sun. To further confirm the coronal signals obtained by BBWLC, comparisons were made with observations of the K-coronagraph of the High Altitude Observatory and the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. We conclude that BBWLC eventually observed the white-light corona in its first scientific flight.

The magnetic fields and dynamical processes in the solar polar regions play a crucial role in the solar magnetic cycle and in supplying mass and energy to the fast solar wind, ultimately being vital in controlling solar activities and driving space weather. Despite numerous efforts to explore these regions, to date no imaging observations of the Sun's poles have been achieved from vantage points out of the ecliptic plane, leaving their behavior and evolution poorly understood. This observation gap has left three top-level scientific questions unanswered: How does the solar dynamo work and drive the solar magnetic cycle? What drives the fast solar wind? How do space weather processes globally originate from the Sun and propagate throughout the solar system? The Solar Polarorbit Observatory(SPO) mission, a solar polar exploration spacecraft, is proposed to address these three unanswered scientific questions by imaging the Sun's poles from high heliolatitudes. In order to achieve its scientific goals, SPO will carry six remote-sensing and four in-situ instruments to measure the vector magnetic fields and Doppler velocity fields in the photosphere, to observe the Sun in the extreme ultraviolet, X-ray, and radio wavelengths, to image the corona and the heliosphere up to 45 Rs, and to perform in-situ detection of magnetic fields,and low-and high-energy particles in the solar wind. The SPO mission is capable of providing critical vector magnetic fields and Doppler velocities of the polar regions to advance our understanding of the origin of the solar magnetic cycle, providing unprecedented imaging observations of the solar poles alongside in-situ measurements of charged particles and magnetic fields from high heliolatitudes to unveil the mass and energy supply that drive the fast solar wind, and providing observational constraints for improving our ability to model and predict the three-dimensional(3D) structures and propagation of space weather events.

We report the detection of an extended very-high-energy (VHE) γ-ray source coincident with the location of middle-aged (62.4 kyr) pulsar PSR J0248+6021, by using the LHAASO-WCDA data of live 796 d and LHAASO-KM2A data of live 1216 d. A significant excess of γ-ray induced showers is observed both by WCDA in energy bands of 1–25 TeV and KM2A in energy bands of >25 TeV with 7.3σ and 13.5σ, respectively. The best-fit position derived through WCDA data is R.A. = 42.06° ± 0.12° and Dec. = 60.24° ± 0.13° with an extension of 0.69°±0.15° and that of the KM2A data is R.A.= 42.29° ± 0.13° and Dec. = 60.38° ± 0.07° with an extension of 0.37° ±0.07°. No clear extended multiwavelength counterpart of this LHAASO source has been found from the radio band to the GeV band. The most plausible explanation of the VHE γ-ray emission is the inverse Compton process of highly relativistic electrons and positrons injected by the pulsar. These electrons/positrons are hypothesized to be either confined within the pulsar wind nebula or to have already escaped into the interstellar medium, forming a pulsar halo.

Context. The Mg I 12.32 mu m line is highly sensitive to magnetic fields due to its long wavelength, making it a promising tool for precise solar-magnetic-field measurements. The formation of this line is significantly influenced by nonlocal thermodynamic equilibrium (NLTE) effects. Aims. Previous studies have shown that the Mg I 12.32 mu m line exhibits different behaviors in various regions of the Sun. This study focuses on the peak intensity of the Mg I 12.32 mu m line to analyze its relationship with the physical parameters of the solar atmosphere and its formation mechanism. Methods. We employed the Rybicki-Hummer (RH) 1.5D radiative transfer code to synthesize the Stokes profiles of the Mg I 12.32 mu m line based on a three-dimensional solar atmospheric model of a sunspot and its surrounding quiet Sun. By computing RxiDelta xi, where Rxi is the average response function and Delta xi is the difference in physical parameters between the two models being compared, we identified the atmospheric height and physical parameters that most significantly influence the normalized peak intensity in the quiet Sun and the active region, respectively. Results. In analyzing the synthesized Stokes profiles, we found two key features: (1) in the quiet Sun, the normalized peak intensity is strong at the centers of the granules and weakens in the intergranular lanes; (2) in the sunspot umbra, the normalized peak intensity is generally weak, with only a few areas showing evident emission. Through the analysis of the response functions, we identified the causes of these differences. In the quiet Sun, the differences in normalized peak intensity are primarily attributed to temperature variations at log tau500; the logarithm of the continuum optical depth at lambda = 500 nm, ranging from -0.21 to 0.91 and from -1.65 to -0.76; as well as to temperature and density variations at log tau500 ranging from -3.86 to -2.38. In the sunspot umbra, the differences are mainly due to density variations at log tau500 ranging from -0.96 to 1.26. In addition, we discussed the mechanisms through which these physical parameters influence the normalized peak intensity.

The ultra-high-energy (UHE) gamma-ray source 1LHAASO J0007+7303u is positionally associated with the composite SNR CTA1 that is located at high Galactic Latitude b ≈ 10.5°. This provides a rare opportunity to spatially resolve the component of the pulsar wind nebula (PWN) and supernova remnant (SNR) at UHE. This paper conducted a dedicated data analysis of 1LHAASO J0007+7303u using the data collected from December 2019 to July 2023. This source is well detected with significances of 21σ and 17σ at 8–100 TeV and >100 TeV, respectively. The corresponding extensions are determined to be 0.23°±0.03° and 0.17°±0.03°. The emission is proposed to originate from the relativistic electrons accelerated within the PWN of PSR J0007+7303. The energy spectrum is well described by a power-law with an exponential cutoff function dN/dE=(42.4± 4.1)(E 20 TeV)^-2.31± 0.11 exp(-E 110± 25 TeV) TeV−1 cm−2 s−1 in the energy range from 8 to 300 TeV, implying a steady-state parent electron spectrum dN_e/dE_e∝ (E_e 100 TeV)^-3.13± 0.16 exp[(-E_e373± 70 TeV)^2] at energies above ≈ 50 TeV. The cutoff energy of the electron spectrum is roughly equal to the expected current maximum energy of particles accelerated at the PWN terminal shock. Combining the X-ray and gamma-ray emission, the current space-averaged magnetic field can be limited to ≈ 4.5 µG. To satisfy the multi-wavelength spectrum and the γ-ray extensions, the transport of relativistic particles within the PWN is likely dominated by the advection process under the free-expansion phase assumption.

This study is to correct magnetic saturation and wavelength shift in Full-disk Magnetograph (FMG) solar magnetic field measurements on the Advanced Space-based Solar Observatory (ASO-S) satellite. Due to its single-wavelength polarization data limitations, currently, FMG relies on linear calibration. We propose a residual network model to output a line-of-sight (LOS) magnetic field which is trained with HMI LOS magnetic fields as target, and FMG Stokes I, V data and LOS velocity components as inputs. Compared to traditional methods, our model achieves lower MAE, RMSE, and improved consistency with the target, while also demonstrating robustness to wavelength shift, offering more accurate magnetic field measurements.

The Water Cherenkov Detector Array (WCDA) is one of the components of Large High Altitude Air Shower Observatory (LHAASO) and can monitor any sources over two-thirds of the sky for up to 7 h per day with >98 per cent duty cycle. In this work, we report the detection of two outbursts of the Fanaroff-Riley I radio galaxy NGC 1275 that were detected by LHAASO-WCDA between 2022 November and 2023 January with statistical significance of 5.2 sigma and 8.3 sigma. The observed spectral energy distribution in the range from 500 GeV to 3 TeV is fitted by a power law with the best-fitting spectral index of alpha = -3.37 +/- 0.52 and -3.35 +/- 0. 29, respectively. The outburst flux above 0.5 TeV was (4.55 +/- 4.21) x10(-11) cm(-2) s(-1) and (3.45 +/- 1.78) x10(-11) cm(-2) s(-1), corresponding to 60 per cent and 45 per cent of Crab Nebula flux, respectively. Variation analysis reveals the variability time-scale of days at the TeV energy band. A simple test by one-zone synchrotron self-Compton model reproduces the data in the gamma-ray band well.