Search Publications
Limb Observations of Global Solar Coronal Extreme-ultraviolet Wavefronts: The Inclination, Kinematics, Coupling with the Expanding Coronal Mass Ejections, and Connection with the Coronal Mass Ejection Driven Shocks
Wang, Rui; Liu, Ying D.; Hu, Huidong +3 more
We select and investigate six global solar extreme-ultraviolet (EUV) wave events using data from the Solar Dynamics Observatory and the Solar and Heliospheric Observatory. These eruptions are all on the limb but recorded as halo coronal mass ejections (CMEs) because the CME-driven shocks have expanded laterally to the opposite side. With the limb …
Estimating the Total Energy Content in Escaping Accelerated Solar Electron Beams
Reid, Hamish A. S.; James, Alexander W.
Quantifying the energy content of accelerated electron beams during solar eruptive events is a key outstanding objective that must be constrained to refine particle acceleration models and understand the electron component of space weather. Previous estimations have used in situ measurements near the Earth, and consequently suffer from electron-be…
Investigating the Impact of Atomic Data Uncertainties on the Measured Physical Parameters of the Perseus Galaxy Cluster
Raymond, John; Foster, Adam R.; Smith, Randall +4 more
Accurate atomic data and plasma models are essential for interpreting the upcoming high-quality spectra from missions like XRISM and Athena. Estimating physical quantities, like temperature, abundance, turbulence, and the resonance scattering factor, is highly dependent on the underlying atomic data. We use the AtomDB tool variableapec to estimate…
Complex K: Supernova Origin of Anomalous-velocity H I Structure
Jorissen, A.; Verschuur, G. L.; Schmelz, J. T. +1 more
We address one of the lingering mysteries of high-velocity clouds: If the anomalous negative velocities are the result of the approaching gas from old supernovae, then where are the receding counterparts of the expanding shells? Data from the λ-21 cm Galactic neutral hydrogen EBHIS survey (Winkel et al.) show multiple signatures of the expanding s…
Radio Morphology of Gamma-Ray Sources: Double-lobed Radio Sources
Stalin, C. S.; Saikia, D. J.; Domínguez, Alberto +1 more
The extragalactic γ-ray sky is dominated by relativistic jets aligned to the observer's line of sight, i.e., blazars. A few of their misaligned counterparts, e.g., radio galaxies, are also detected with the Fermi-Large Area Telescope (LAT), albeit in a small number (∼50), indicating the crucial role played by the jet viewing angle in detecting γ-r…
Deep Chandra Observations of NGC 5728. III. Probing the High-resolution X-Ray Morphology and Multiphase Interstellar Medium Interactions in the Circumnuclear Region
Elvis, M.; Fabbiano, G.; Maksym, W. P. +2 more
We present a detailed imaging analysis of 260 ks of subarcsecond resolution Chandra (ACIS-S) observations of the nearby Seyfert 2 galaxy NGC 5728. Our study focuses on the bright and diffuse soft X-ray emission within the galaxy's inner ∼1 kpc. By comparing the X-ray emission across different energy bands, we identify localized variations in the a…
Time-lapse Very Long Baseline Interferometry Imaging of the Close Active Binary HR 1099
Golay, Walter W.; Mutel, Robert L.; Abbuhl, Evan E.
We report multiepoch astrometric very long baseline interferometry observations of the chromospherically active binary HR 1099 (V711 Tau, HD 22468) at six epochs over 63 days using the Very Long Baseline Array at 22.2 GHz. We determined hourly radio positions at each epoch with a positional uncertainty significantly smaller than the component sepa…
Progenitor Constraint-incorporating Shell Merger: The Case of Supernova Remnant G359.0–0.9
Sato, Toshiki; Uchida, Hiroyuki; Tsuru, Takeshi Go +5 more
It is generally hard to put robust constraints on progenitor masses of supernovae and supernova remnants (SNRs) observationally, while they offer tantalizing clues to understanding explosion mechanisms and mass distribution. Our recent study suggests that "shell merger," which is theoretically expected for stellar evolution, can appreciably affect…
Star Formation, Nebulae, and Active Galactic Nuclei in CLASH Brightest Cluster Galaxies. I. Dependence on Core Entropy of Intracluster Medium
Donahue, Megan; Ohyama, Youichi; Lim, Jeremy +2 more
We set the stage for reassessing how star formation, emission-line nebulae, and active galactic nuclei (AGNs) in brightest cluster galaxies (BCGs) depend on the thermodynamics of the intracluster medium (ICM). Our work is based on the 25 clusters observed in the CLASH program for which the aforementioned attributes in their BCGs can be well scruti…
An Eddington-limited Accretion Disk Wind in the Narrow-line Seyfert 1 PG 1448+273
Porquet, D.; Reeves, J. N.; Braito, V. +5 more
PG 1448+273 is a luminous, nearby (z = 0.0645), narrow-line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. Previous X-ray observations of PG 1448+273 with XMM-Newton in 2017 and NuSTAR in 2022 revealed the presence of an ultrafast outflow, as seen through its blueshifted iron (Fe) K absorption profile, where the outflow velo…