Search Publications
Recent Formation of a Spiral Disk Hosting Progenitor Globular Clusters at the Center of the Perseus Brightest Cluster Galaxy. I. Spiral Disk
Ohyama, Youichi; Lim, Jeremy; Yeung, Michael C. H.
We address the nature and origin of a spiral disk at the center of NGC 1275, the giant elliptical galaxy at the center of the Perseus cluster, that spans a radius of ~5 kpc. By comparing stellar absorption lines measured in long-slit optical spectra with synthetic spectra for single stellar populations, we find that fitting of these lines requires…
A GMOS/IFU Study of Jellyfish Galaxies in Massive Clusters
Lee, Myung Gyoon; Lee, Jeong Hwan; Kang, Jisu +2 more
Jellyfish galaxies are an intriguing snapshot of galaxies undergoing ram pressure stripping (RPS) in dense environments, showing spectacular star-forming knots in their disks and tails. We study the ionized gas properties of five jellyfish galaxies in massive clusters with Gemini GMOS/Integral Field Unit observations: MACSJ0916-JFG1 (z = 0.330), M…
Improved Model of X-Ray Emission from Hot Accretion Flows
Zdziarski, Andrzej A.; Szanecki, Michał; Niedźwiecki, Andrzej +1 more
We have developed an improved model of X-ray emission from optically thin, two-temperature accretion flows, kerrflow, using an exact Monte Carlo treatment of global Comptonization as well as with a fully general relativistic description of both the radiative and hydrodynamic processes. It also includes pion-decay electrons, whose synchrotron emiss…
Catching the Butterfly and the Homunculus of η Carinae with ALMA
Gull, Theodore R.; Menten, Karl M.; Toalá, Jesús A. +7 more
The nature and origin of the molecular gas component located in the circumstellar vicinity of η Carinae are still far from being completely understood. Here, we present Atacama Large Millimeter/submillimeter Array CO(3-2) observations with a high angular resolution (~0.″15) and a great sensitivity that are employed to reveal the origin of this com…
Estimating the Injection Duration of 20 MeV Protons in Large Western Solar Energetic Particle Events
Lugaz, Noé; Li, Gen
An ad hoc analytical calculation is presented to infer the duration of injection of 20 MeV protons in 21 selected western solar energetic particle (SEP) events. We convolve the solution of diffusion equation with a "triangle" source to model the time-intensity profiles over the onset and the peaking phase. The effects of "corotating" flux tubes an…
Modeling the Photometric Variability of Alpha2 CVn with a Dynamical Magnetosphere
Pfeffer, Cameron M.; McSwain, M. Virginia
Alpha2 Canum Venaticorum (α 2 CVn) is a strongly magnetic star with peculiar chemical signatures and periodic variability that have been long attributed to the diffusion of magnetic elements through the photosphere, leading to chemical spots across the stellar surface. However, recent studies of other magnetic hot stars are c…
Periodic Oscillations in LASCO Coronal Mass Ejection Speeds: Space Seismology
Gopalswamy, Nat; Yashiro, Seiji; Michalek, Grzegorz
Coronal mass ejections (CMEs) are energetic eruptions of organized magnetic structures from the Sun. Therefore, the reconnection of the magnetic field during ejection can excite periodic speed oscillations of CMEs. A previous study showed that speed oscillations are frequently associated with CME propagation. The Solar and Heliospheric Observatory…
PSP/IS⊙IS Observation of a Solar Energetic Particle Event Associated with a Streamer Blowout Coronal Mass Ejection during Encounter 6
Palmerio, E.; Mitchell, D. G.; McComas, D. J. +21 more
In this paper we examine a low-energy solar energetic particle (SEP) event observed by IS⊙IS's Energetic Particle Instrument-Low (EPI-Lo) inside 0.18 au on 2020 September 30. This small SEP event has a very interesting time profile and ion composition. Our results show that the maximum energy and peak in intensity are observed mainly along the ope…
A Time-dependent Self-similar Reconstruction of Solar Coronal Mass Ejections Based on the Gibson-Low Model
Dai, Xinghua
The analytic Gibson-Low (GL) model, a time-dependent self-similar solution of the magnetohydrodynamics, is first used to directly reconstruct a coronal mass ejection (CME) through the method of forward modeling in this study. A systematic description of the GL model is presented at the beginning, and a set of parameters is introduced to define the…
The Physical Properties of Star-forming Galaxies with Strong [O III] Lines at z = 3.25
Fang, Min; Zheng, Xian Zhong; Xu, Haiguang +13 more
We present an analysis of physical properties of 34 [O III] emission-line galaxies (ELGs) at z = 3.254 ± 0.029 in the Extended Chandra Deep Field South (ECDFS). These ELGs are selected from deep narrow H2S(1) and broad K s imaging of 383 arcmin2 obtained with CFHT/WIRCam. We construct spectral energy distributions …