Search Publications
The Hydrostatic Mass of A478: Discrepant Results from Chandra, NuSTAR, and XMM-Newton
Wik, Daniel R.; Schellenberger, Gerrit; Wang, Qian H. S. +3 more
Galaxy clusters are the most recently formed and most massive, gravitationally bound structures in the Universe. The number of galaxy clusters formed is highly dependent on cosmological parameters, such as the dark matter density, σ 8, and Ω m . The number density is a function of the cluster mass, which can be estimated from…
Modeling the Radiation Environment of Energetic Particles at Mars Orbit and a First Validation against TGO Measurements
Guo, Jingnan; Liu, Weihao; Semkova, Jordanka +1 more
Sending astronauts to Mars will be a milestone of future deep space exploration activities. However, energetic particle radiation in deep space and in the Mars environment is a major risk to the health of future human explorers. The nominal Martian surface radiation field contains primary Galactic Cosmic Ray (GCR) particles and secondary particles…
The SPHEREx Target List of Ice Sources (SPLICES)
Kang, Miju; Lee, Jeong-Eun; Lee, Ho-Gyu +16 more
One of the primary objectives of the SPHEREx mission is to understand the origin of molecules such as H2O, CO2, and other volatile compounds at the early stages of planetary system formation. Because the vast majority of these compounds-typically exceeding 95%-exist in the solid phase rather than the gaseous phase in the syst…
Influence of an Upstream Dynamic Pressure Pulse on Venus-Solar Wind Interaction by Multispecies Magnetohydrodynamic Simulation
Cao, Jinbin; Li, Yun; Xiong, Ruijing +4 more
As an unmagnetized planet, Venus does not have a global dipole magnetic field like Earth. The solar wind interacts directly with the Venusian ionosphere. In this paper, the interaction between solar wind and the Venusian upper atmosphere is investigated by conducting a three-dimensional multispecies magnetohydrodynamic (MHD) model, in which the Ve…
The Chemodynamical Nature of the Triangulum-Andromeda Overdensity
Placco, Vinicius M.; Limberg, Guilherme; Rossi, Silvia +7 more
We present a chemodynamical study of the Triangulum-Andromeda overdensity (TriAnd) employing a sample of 31 candidate stars observed with the GRACES high-resolution (R = 40,000) spectrograph at the Gemini North (8.1 m) telescope. TriAnd is a stellar substructure found toward the outer disk of the Milky Way, located at R GC ~ 18 kpc from…
Are Nonthermal Velocities in Active Region Coronal Loops Anisotropic?
Hahn, Michael; Asgari-Targhi, Mahboubeh; Savin, Daniel Wolf
We have measured line widths in active region coronal loops in order to determine whether the nonthermal broadening is anisotropic with respect to the magnetic field direction. These nonthermal velocities are caused by unresolved fluid motions. Our analysis method combines spectroscopic data and a magnetic field extrapolation. We analyzed spectra …
Solar Filament Eruptions in H α Doppler Velocity
Pevtsov, A. A.; Tlatov, A. G.; Berezin, I. A.
We use observations taken with a novel solar telescope spectroheliograph to investigate the association between the early filament rise and coronal mass ejections (CMEs). The instrument allows the H α full line profile to be registered in each pixel of the solar disk with a time cadence of about 1 minute. We analyze observations of thr…
Bubble in the Whale: Identifying the Optical Counterparts and Extended Nebula for the Ultraluminous X-Ray Sources in NGC 4631
Feng, Hua; Liu, Jifeng; Cai, Zheng +9 more
We present a deep optical imaging campaign on the starburst galaxy NGC 4631 with CFHT/MegaCam. By supplementing the HST/ACS and Chandra/ACIS archival data, we search for the optical counterpart candidates of the five brightest X-ray sources in this galaxy, four of which are identified as ultraluminous X-ray sources (ULXs). The stellar environments…
Estimating Coronal Mass Ejection Mass and Kinetic Energy by Fusion of Multiple Deep-learning Models
Wang, Haimin; Yurchyshyn, Vasyl; Li, Jialiang +5 more
Coronal mass ejections (CMEs) are massive solar eruptions, which have a significant impact on Earth. In this paper, we propose a new method, called DeepCME, to estimate two properties of CMEs, namely, CME mass and kinetic energy. Being able to estimate these properties helps better understand CME dynamics. Our study is based on the CME catalog mai…
Climatological Gravity Waves in the Middle and Upper Atmosphere of Mars Based on ACS/TGO Observations
Zhang, Yun; Zhang, Jie; Ji, Qianqian +2 more
Gravity waves (GWs) are important for the vertical coupling of the Martian atmosphere. The middle atmosphere is the key region where GWs propagate to the upper thermosphere and generate momentum and energy exchange, but the knowledge of middle-atmosphere GWs is incomplete, due to the lack of observations with the kilometer-scale resolution. We hav…