Search Publications
Statistical Investigation of Wave Propagation in the Quiet-Sun Using IRIS Spectroscopic Observations
Srivastava, A. K.; Scullion, E.; Kayshap, P. +2 more
In this analysis, we use spectroscopic observations of the quiet Sun made by the IRIS instrument and investigate wave propagation. We analyze various spectral lines formed in different atmospheric layers, such as the photosphere, chromosphere, and transition region. We examine the Doppler velocity time series at various locations in the quiet Sun …
Filament Accretion and Fragmentation in the Perseus Molecular Cloud
Caselli, Paola; Di Francesco, James; Ginsburg, Adam +6 more
Observations suggest that filaments in molecular clouds can grow by mass accretion while forming cores via fragmentation. Here, we present one of the first large-sample studies of filament accretion using velocity gradient measurements of star-forming filaments on the ∼0.05 pc scale with NH3 observations of the Perseus Molecular Cloud, …
A Search for Soft X-Ray Emission Lines in the Afterglow Spectrum of GRB 221009A
Tiengo, Andrea; Campana, Sergio; Braito, Valentina +1 more
GRB 221009A was the brightest gamma-ray burst (GRB) of all time (BOAT), surpassing in prompt brightness all GRBs discovered in ∼50 yr and in afterglow brightness in ∼20 yr. We observed the BOAT with XMM-Newton 2.3 days after the prompt. The X-ray afterglow was still very bright and we collected the largest number of photons with the reflection gra…
The Dustiest Galactic S Stars: Mid-infrared Spectra from SOFIA/FORCAST
Sloan, G. C.; Kraemer, Kathleen E.; Ramirez, Ramses M.
We present spectra of 12 of the reddest, and hence dustiest, S stars in the Milky Way, observed with the FORCAST grisms on SOFIA. S stars are asymptotic giant branch (AGB) stars with C/O ∼ 1, so their molecular and dust chemistries are dominated by neither O nor C, often leading to atypical spectral features from their molecules and dust grains. A…
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…