Search Publications
Dynamics and structure of network magnetic fields: supergranular vortex expansion-contraction
Chian, Abraham C. -L.; Rempel, Erico L.; Gošić, Milan +1 more
We report on the formation of a large magnetic coherent structure in a vortex expansion-contraction interval, resulting from the merger of two plasmoids driven by a supergranular vortex observed by Hinode in the quiet-Sun. Strong vortical flows at the interior of vortex boundary are detected by the localized regions of high values of the instantan…
Acceleration of an interplanetary shock through the magnetosheath: a global hybrid simulation
Modolo, R.; Fontaine, D.; Savoini, P. +1 more
According to most observations and simulations, interplanetary shocks slow down when they propagate through the magnetosheath. In this article, we present results from a self-consistent global hybrid PIC simulation of an interplanetary shock which, by contrast, accelerates as it propagates through the magnetosheath. In this simulation, the solar w…
Morphological and Structural Characterization of Shortening Landforms on Mars
Klimczak, Christian; McCullough, Leta R.; Crane, Kelsey T. +1 more
The lithosphere of Mars accommodates horizontal shortening through folding and faulting, producing landforms described as wrinkle ridges or lobate scarps. Despite this nomenclature, we lack a deep understanding of the drivers of morphological differences observed between landform types. This study aims to develop a quantitative model for shortenin…
On the Contribution of Latitude-Dependent ULF Waves to the Radial Transport of Off-Equatorial Relativistic Electrons in the Radiation Belts
Angelopoulos, Vassilis; Li, Xinlin; Ergun, Robert E. +15 more
Ultra-low frequency (ULF) waves radially diffuse hundreds-keV to few-MeV electrons in the magnetosphere, as the range of drift frequencies of such electrons overlaps with the wave frequencies, leading to resonant interactions. Theoretically this process is described by analytic expressions of the resonant interactions between electrons and ULF wav…
Beyond the rings: Polar ring galaxy NGC 4262 and its globular cluster system
Mathew, Blesson; Kartha, Sreeja S.; Akhil, Krishna R.
In the context of the hierarchical model of galaxy evolution, polar ring galaxies (PRGs) are considered the intermediate phase between ongoing mergers and quiescent galaxies. This study explores the globular cluster system (GCS) and its properties in the nearest PRG, NGC4262, serving as a pilot investigation to study GCS in nearby PRGs. We utilize…
Detailed mapping of the Galactic disc structure in the solar neighbourhood through LAMOST K dwarfs
Qiu, Dan; Tian, Hao; Liu, Chao +4 more
The Galactic disc is one of the main components of the Milky Way, which contributes most of the luminosity. Its structure is essential for understanding the formation and evolution of the Milky Way. Using 174 443 K-type dwarf stars observed by both Large Sky Area Multi-Object Fiber Spectroscopic Telescope and Gaia Data Release 3, we study the disc…
The factors that influence protostellar multiplicity: I. Gas temperature, density, and mass in Perseus with Nobeyama
Johnstone, D.; Hacar, A.; Sakai, N. +9 more
Context. Protostellar multiplicity is common at all stages and mass ranges. However, the factors that determine the multiplicity of protostellar systems have not been systematically characterized through their molecular gas. Aims. We characterize the physical properties of the Perseus molecular cloud at ≥5000 AU scales by mapping the diagnostic mo…
AGN-driven outflows in the OH absorber galaxy IRAS 19154+2704
Robinson, Andrew; Storchi-Bergmann, Thaisa; Riffel, Rogemar A. +4 more
We present a two-dimensional study of the gas distribution, excitation, and kinematics of the OH absorber galaxy IRAS 19154+2704 using Gemini Multi-Object Spectrograph integral field unit observations. Its continuum image shows a disturbed morphology indicative of a past or ongoing interaction. The ionized gas emission presents two kinematic compo…
Effect of area divergence and frequency on damping of slow magnetoacoustic waves propagating along umbral fan loops
Gupta, Girjesh R.; Rawat, Ananya
Waves play an important role in the heating of solar atmosphere; however, observations of wave propagation and damping from the solar photosphere to corona through chromosphere and transition region are very rare. Recent observations have shown propagation of 3-min slow magnetoacoustic waves (SMAWs) along fan loops from the solar photosphere to co…
Classification and characterization using HCT/HFOSC spectra of carbon stars selected from the HES survey
Goswami, Aruna; Purandardas, Meenakshi
We present results from the analysis of 88 carbon stars selected from Hamburg/ESO (HES) survey using low-resolution spectra (R ∼1330 & 2190). The spectra were obtained with the Himalayan Faint Object Spectrograph Camera (HFOSC) attached to the 2-m Himalayan Chandra Telescope (HCT). Using well-defined spectral criteria based on the strength of …