Publications (56)
Chandra view of Abell 407: the central compact group of galaxies and the interaction between the radio AGN and the ICM
Chao Geng, Chong Ge, Dharam V. Lal +8
Abell 407 (A407) is a unique galaxy cluster hosting a central compact group of nine galaxies (named as 'Zwicky's Nonet'; G1 - G9 in this work) within a 30 kpc radius region. The cl…
A timing view of the heartbeat state of GRS 1915+105
Shu-Ping Yan, Li Ji, Mariano Méndez +10
We present a timing analysis of two Rossi X-ray Timing Explorer observations of the microquasar GRS 1915+105 during the heartbeat state. The phase-frequency-power maps show that th…
A Study of Opacity Ranges for Transparent Overlays in 3D Landscapes
Jan Hombeck, Li Ji, Kai Lawonn +1
{When visualizing data in a realistically rendered 3D virtual environment, it is often important to represent not only the 3D scene but also overlaid information about additional,…
Scientific Objectives of the Hot Universe Baryon Surveyor (HUBS) Mission
Joel Bregman, Renyue Cen, Yang Chen +51
The Hot Universe Baryon Surveyor (HUBS) is a proposed space-based X-ray telescope for detecting X-ray emissions from the hot gas content in our universe. With its unprecedented spa…
CO-CHANGES II: spatially resolved IRAM 30M CO line observations of 23 nearby edge-on spiral galaxies
Yan Jiang, Jiang-Tao Li, Qing-Hua Tan +6
Molecular gas, as the fuel for star formation, and its relationship with atomic gas are crucial for understanding how galaxies regulate their star forming (SF) activities. We condu…
The MALATANG survey: Dense gas distribution on sub-kiloparsec scales across the disk of M82
Jian-Fa Wang, Yu Gao, Qing-Hua Tan +23
We present observations of HCN J=4-3 and HCO^+ J=4-3 lines obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey, combined with archival HCN J=1-0 and HCO^…
Directional carrier transport in micrometer-thick gallium oxide films for high-performance deep-ultraviolet photodetection
Wenrui Zhang, Wei Wang, Jinfu Zhang +7
Incorporating emerging ultrawide bandgap semiconductors with a metal-semiconductor-metal (MSM) architecture is highly desired for deep-ultraviolet (DUV) photodetection. However, sy…
X-ray Signatures of Non-Equilibrium Ionization Effects in Galaxy Cluster Accretion Shock Regions
Ka-Wah Wong, Craig L. Sarazin, Li Ji
The densities in the outer regions of clusters of galaxies are very low, and the collisional timescales are very long. As a result, heavy elements will be under-ionized after they…
In-Context World Modeling for Robotic Control
Siyin Wang, Junhao Shi, Senyu Fei +4
Modern Vision-Language-Action (VLA) models often fail to generalize to novel setups, such as altered camera viewpoints or robot morphologies, because they are typically conditioned…
Modeling the cool gas clumps in the circumgalactic medium
Hang Yang, Zhijie Qu, Joel N. Bregman +1
A major challenge in CGM studies is determining the three-dimensional (3D) properties from the observed projected observations. Here, we decompose the 3D gas density and spatial di…
SRPO: Self-Referential Policy Optimization for Vision-Language-Action Models
Senyu Fei, Siyin Wang, Li Ji +7
Vision-Language-Action (VLA) models excel in robotic manipulation but are constrained by their heavy reliance on expert demonstrations, leading to demonstration bias and limiting p…
Joint Fit of Warm Absorbers in COS & HETG Spectra of NGC 3783
Xiao-Dan Fu, Shui-Nai Zhang, Wei Sun +2
Warm Absorbers (WAs), as an important form of AGN outflows, show absorption in both UV and X-ray band. Using XSTAR generated photoionization models, for the first time we present a…
HiMe: Hierarchical Embodied Memory for Long-Horizon Vision-Language-Action Control
Li Ji, Siyin Wang, Pengfang Qian +5
Current Vision-Language-Action (VLA) models excel at robotic manipulation but often struggle with non-Markovian tasks requiring long-term memory and reasoning due to their reliance…
Serendipitous Discovery of Warm Absorbers in the Seyfert 2 Galaxy IRAS 18325-5926
Shui-Nai Zhang, Qiu-Sheng Gu, Li Ji +1
Warm absorption is a common phenomenon in Seyfert 1s and quasars, but rare in Seyfert 2s. In this paper, we report the detection of warm absorbers with high energy resolution in th…
The XMM-Newton Line Emission Analysis Program (X-LEAP) III: Earth's Magnetospheric X-ray Emission Revealed by 22-Year XMM-Newton Observations
Zeyang Pan, Zhijie Qu, Yuqi Gong +5
The magnetosphere, protecting the Earth from intense solar activity, is also shaped by the solar wind, while its structure is still uncertain in observation. In this study, we map…
Pressure Balance and Energy Budget of the Nuclear Superbubble of NGC 3079
Jiang-Tao Li, Wei Sun, Li Ji +1
Superbubbles in the nuclear region of galaxies could be produced by the AGN or nuclear starburst via different driving forces. We report analysis of the multi-wavelength data of th…
Charge exchange emission and cold clumps in multi-phase galactic outflows
Kinwah Wu, Kaye Jiale Li, Ellis R. Owen +3
Large-scale outflows from starburst galaxies are multi-phase, multi-component fluids. Charge-exchange lines which originate from the interfacing surface between the neutral and ion…
Disc-corona interaction in the heartbeat state of GRS 1915+105
Shu-Ping Yan, Li Ji, Si-Ming Liu +10
Timing analysis provides information about the dynamics of matter accreting on to neutron stars and black holes, and hence is crucial for studying the physics of the accretion flow…
Probing the He II re-Ionization ERa via Absorbing C IV Historical Yield (HIERACHY) II: Project Design, Current Status, and Examples of Initial Data Products
Jiang-Tao Li, Xiaodi Yu, Huiyang Mao +22
The He II reionization epoch is expected to take place at . In this stage, the helium and metals in the inter-galactic medium (IGM) are further ionized with additional co…
Isolated neutron star candidates from the fourth generation XMM-Newton catalogues
Adriana M. Pires, Christian Motch, Jan Kurpas +9
X-ray thermally emitting isolated neutron stars (XINSs) are a rare population that provides insights into neutron star cooling, magnetic-field evolution, and Galactic demographics.…
ABC-Bench: Benchmarking Agentic Backend Coding in Real-World Development
Jie Yang, Honglin Guo, Li Ji +11
The evolution of Large Language Models (LLMs) into autonomous agents has expanded the scope of AI coding from localized code generation to complex, repository-level, and execution-…
Learning to Move Before Learning to Do: Task-Agnostic pretraining for VLAs
Junhao Shi, Siyin Wang, Xiaopeng Yu +3
Vision-Language-Action (VLA) models are fundamentally bottlenecked by the scarcity of expert demonstrations -- triplets of observations, instructions, and actions that are costly t…
ContextWeave: A Real-World Workflow Benchmark
Bo Wang, Yuqian Yao, Enxi Wang +25
Memory is essential as language agents move from isolated tasks to long-horizon, stateful workflows, yet existing evaluations often reduce it to retrieval or question answering. We…
X-ray Spectroscopic Evidence of Charge Exchange Emission in the Disk of M51
Shuinai Zhang, Q. Daniel Wang, Wei Sun +3
In the disks of spiral galaxies, diffuse soft X-ray emission is known to be strongly correlated with star-forming regions. However, this emission is not simply from a thermal-equil…
The BIG X-ray tail
Chong Ge, Ming Sun, Masafumi Yagi +9
Galaxy clusters grow primarily through the continuous accretion of group-scale haloes. Group galaxies experience preprocessing during their journey into clusters. A star-bursting c…
Non-Equilibrium Ionization Model for Stellar Cluster Winds and its Application
Li Ji, Q. Daniel Wang, John Kwan
We have developed a self-consistent physical model for super stellar cluster winds based on combining a 1-D steady-state adiabatic wind solution and a non-equilibrium ionization ca…
Mapping Diffuse Emission in Lyman UV band
Li Ji, Zheng Lou, Jinlong Zhang +38
The CAFE (Census of warm-hot intergalactic medium, Accretion, and Feedback Explorer) and LyRIC (Lyman UV Radiation from Interstellar medium and Circum-galactic medium) have been pr…
Deep Chandra observations of diffuse hot plasma in M83
Q. Daniel Wang, Yuxuan Zeng, Akos Bogda +1
It is widely believed that galaxy formation and evolution is regulated by stellar mechanical feedback in forms of fast stellar winds and supernova explosions. However, the coupling…
Three dimensional ring vortex solitons and their stability in Bose-Einstein condensates under magnetic confinement
Li Ji, Deng-Shan Wang, Zhi-Yong Wu +2
The three-dimensional study of the ring vortex solitons is conducted for both attractive and repulsive BECs subject to harmonic potential confinement. A family of stationary ring v…
Probing the \ion{He}{2} re-Ionization ERa via Absorbing \ion{C}{4} Historical Yield (HIERACHY) IV: A complex redshifted absorption system intrinsic to quasar
Huiyang Mao, Jiang-Tao Li, Xiaodi Yu +3
High-resolution spectra provide a powerful tool in studying the associated absorption lines (AALs) in quasars. We present a case study of the quasar J014741-030247 at 4.75…
The warm-hot intergalactic medium in inter-cluster filaments -- A forecast for HUBS observations based on eRASS1 superclusters
Yuanyuan Zhao, Haiguang Xu, Ang Liu +8
Cosmological simulations indicate that nearly half of the baryons in the nearby Universe are in the warm-hot intergalactic medium (WHIM) phase, and about a half them reside in cosm…
CHANG-ES. XXX. 10 kpc Radio Lobes in The Sombrero Galaxy
Yang Yang, Jiang-Tao Li, Theresa Wiegert +8
We report the discovery of the 10 kilo-parsec (kpc) scale radio lobes in the Sombrero galaxy (NGC 4594), using data from the Continuum Halos in Nearby Galaxies - an Expanded Very L…
CHANG-ES XXIX: The Sub-kpc Nuclear Bubble of NGC 4438
Jiang-Tao Li, Q. Daniel Wang, Theresa Wiegert +8
AGN bubbles could play an important role in accelerating high-energy CRs and galactic feedback. Only in nearby galaxies could we have high enough angular resolution in multi-wavele…
Twisted-pair unilateral reconnection: A unifying driver for magnetically powered astrophysical bursts
Shu-Ping Yan, Wenhui Yu, Jing Ye +11
Magnetic reconnection in twisted loops has long been invoked as an engine powering energetic transients from black hole accretion to neutron star mergers, yet never directly observ…
Implications of X-Ray Line Variations for 4U1822-371
Li Ji, Norbert S. Schulz, Michael A. Nowak +1
4U 1822-371 is one of the proto-type accretion disk coronal sources with an orbital period of about 5.6 hours. The binary is viewed almost edge-on at a high inclination angle of 83…
Spectral Modeling of Charge Exchange in the Central Region of M51
Hang Yang, Shuinai Zhang, Li Ji
Charge exchange (CX) emission reveals the significant interaction between neutral and ionized interstellar medium (ISM) components of the dense, multiphase, circumnuclear region of…
Persistent incommensurate amorphous/crystalline meta-interfaces enable engineering-grade superlubricity
Wan Wang, Zijun Ding, Panpan Li +7
Friction dissipates a substantial portion of global energy, motivating the pursuit of superlubricity, a state of near-zero friction, in real-world systems. Conventional approaches…
Unleashing Embodied Task Planning Ability in LLMs via Reinforcement Learning
Zhaoye Fei, Li Ji, Siyin Wang +3
Large Language Models (LLMs) have demonstrated remarkable capabilities across various tasks, yet they face significant challenges in embodied task planning scenarios that require c…
Spectral Modeling of the Charge-Exchange X-ray Emission from M82
Shuinai Zhang, Q. Daniel Wang, Li Ji +3
It has been proposed that the charge exchange (CX) process at the interface between hot and cool interstellar gases could contribute significantly to the observed soft X-ray emissi…
Wafer-scale Demonstration of High-voltage beta-Ga2O3 MOSFETs with Excellent Uniformity and over 3kV Breakdown Voltages
Ningtao Liu, Hengrui Zhang, Shujun Zhu +7
This study demonstrates a wafer-scale growth of a 2-inch Si-doped -Ga2O3 (100) epitaxial wafer and the realization of uniform, high-voltage lateral -Ga2O3 MOSFET arrays. Th…
Nex-N1: Agentic Models Trained via a Unified Ecosystem for Large-Scale Environment Construction
AGI Team, Yuxuan Cai, Lu Chen +62
The evolution of Large Language Models (LLMs) from passive responders to autonomous agents necessitates a fundamental shift in learning paradigms -- from static imitation to incent…
A biomimetic feedback loop for sustaining self-lubrication and wear resistance
Fuyan Kang, Shilin Deng, Panpan Li +7
Intelligent materials that self-sense and self-regulate are an emerging frontier in sustainable technology. Here we introduce Cu(Au)/C nanocomposite films that act as bioinspired s…
A Semi-Analytical Model for the Formation and Evolution of Radio Relics in Galaxy Clusters
Yihao Zhou, Haiguang Xu, Zhenghao Zhu +8
Radio relics are Mpc-sized synchrotron sources located in the peripheral regions of galaxy clusters. Models based on the diffuse shock acceleration (DSA) scenario have been widely…
CO-CHANGES I: IRAM 30m CO Observations of Molecular Gas in the Sombrero Galaxy
Yan Jiang, Jiang-Tao Li, Yu Gao +7
Molecular gas plays a critical role in explaining the quiescence of star formation (SF) in massive isolated spiral galaxies, which could be a result of either the low molecular gas…
Baryon content and dynamic state of galaxy clusters: XMM-Newton observations of A1095 and A1926
Chong Ge, Q. Daniel Wang, Todd M. Tripp +3
We have initiated a program to study the baryon content and dynamic state of galaxy clusters. Here we present results primarily from XMM-Newton observations of two optically-select…
Superconductivity in pressurized trilayer LaNiO single crystals
Yinghao Zhu, Di Peng, Enkang Zhang +27
The pursuit of discovering new high-temperature superconductors that diverge from the copper-based paradigm1-3 carries profound implications for elucidating mechanisms behind super…
XMM-Newton RGS spectroscopy of the M31 bulge. I: Evidences for a past AGN half a million years ago
Shuinai Zhang, Q. Daniel Wang, Adam R. Foster +3
Existing analysis based on XMM-Newton/RGS spectra already shows that the G-ratio of the OVII He triplet in the inner bulge of M31 is too high to be consistent with a pure optic…
Chandra and XMM-Newton view of the Warm Absorbing Gas in Mrk 290
Shuinai Zhang, Li Ji, Herman L. Marshall +3
We present a detailed analysis of the Chandra HETGS and XMM-Newton high resolution spectra of the bright Seyfert 1 galaxy, Mrk 290. The Chandra spectra reveal complex absorption fe…
LIBERO-Plus: In-depth Robustness Analysis of Vision-Language-Action Models
Senyu Fei, Siyin Wang, Junhao Shi +10
Visual-Language-Action (VLA) models report impressive success rates on robotic manipulation benchmarks, yet these results may mask fundamental weaknesses in robustness. We perform…
Probing the dynamical state, baryon content, and multiphase nature of galaxy clusters with bright background QSOs
Chong Ge, Q. Daniel Wang, Joseph N. Burchett +5
We have initiated a programme to study the physical/dynamical state of gas in galaxy clusters and the impact of the cluster environment on gaseous halos of individual galaxies usin…
Magnetic Reconnection as a Potential Driver of X-ray Variability in Active Galactic Nuclei
Chen-Ran Hu, Yong-Feng Huang, Lang Cui +13
We present a systematic analysis on the X-ray variability in 13 bright quasars at z > 4.5, combining recent Swift observations from 2021 to 2023 and archival multi-epoch observatio…
Parallelizing the XSTAR Photoionization Code
Michael S. Noble, Li Ji, Andrew Young +1
We describe two means by which XSTAR, a code which computes physical conditions and emission spectra of photoionized gases, has been parallelized. The first is pvm_xstar, a wrapper…
What causes the absence of pulsations in Central Compact Objects in Supernova Remnants?
Qi Wu, Adriana M. Pires, Axel Schwope +3
Most young neutron stars belonging to the class of Central Compact Objects in supernova remnants (CCOs) do not have known periodicities. We investigated seven such CCOs to understa…
Anomaly Detection in Automated Fibre Placement: Learning with Data Limitations
Assef Ghamisi, Todd Charter, Li Ji +3
Conventional defect detection systems in Automated Fibre Placement (AFP) typically rely on end-to-end supervised learning, necessitating a substantial number of labelled defective…
Possible evidence for extended X-ray emission surrounding PSR B0656+14 with eROSITA
Shu Niu, Qiang Yuan, Shui-Nai Zhang +3
Extended very-high-energy -ray emission from middle-aged pulsars as revealed recently by several groundbased -ray experiments has strong implication on the transport of hig…
Resonant scattering effect on the soft X-ray line emission from the hot interstellar medium: I. galactic bulges
Yang Chen, Q. Daniel Wang, Gao-Yuan Zhang +2
Diffuse soft X-ray line emission is commonly used to trace the thermal and chemical properties of the hot interstellar medium, as well as its content, in nearby galaxies. Although…