Search Publications
On the Magnetic and Thermodynamic Properties of Dark Fibrils in the Chromosphere
Kriginsky, Matheus; Oliver, Ramon
Fibrillar structures are ubiquitous in the solar chromosphere. An accurate determination of their properties requires the use of advanced high-resolution observations, which are now becoming broadly available from different observatories. We exploit the capabilities of multi-atom, multiline spectropolarimetric inversions using the Stockholm Invers…
Constraining Solar Wind Transport Model Parameters Using Bayesian Analysis
Parashar, Tulasi N.; Oughton, Sean; Bishop, Mark A. +1 more
We apply nested-sampling Bayesian analysis to a model for the transport of magnetohydrodynamic-scale solar wind fluctuations. The dual objectives are to obtain improved constraints on parameters present in the turbulence transport model (TTM) and to support quantitative comparisons of the quality of distinct versions of the transport model. The TT…
Elemental Abundances at Coronal Hole Boundaries as a Means to Investigate Interchange Reconnection and the Solar Wind
Koukras, Alexandros; Savin, Daniel W.; Hahn, Michael
The origin of the slow solar wind is not well understood, unlike the fast solar wind that originates from coronal holes. In situ elemental abundances of the slow solar wind suggest that it originates from initially closed field lines that become open. Coronal hole boundary regions are a potential source of slow solar wind, as open field lines ther…
What Does the LMC Look Like? It Depends on [M/H] and Age
Rix, Hans-Walter; Andrae, Rene; Chandra, Vedant +2 more
We offer a new way to look at the LMC through stellar mono-abundance and mono-age mono-abundance maps. These maps are based on ≳500,000 member stars with estimates of [M/H] (σ[M/H] ~ 0.17) and age
ASKAP Observations of the Radio Shell in the Composite Supernova Remnant G310.6-1.6
Hopkins, Andrew M.; Kothes, Roland; Lazarević, Sanja +12 more
We report the observations of the radio shell of the supernova remnant (SNR) G310.6–1.6 at 943 MHz from the Evolutionary Map of the Universe (EMU) and the Polarization Sky Survey of the Universe's Magnetism (POSSUM) surveys by using the Australian Square Kilometre Array Pathfinder (ASKAP). We detect polarized emission from the central pulsar wind …
High-frequency Power Spectrum of Active Galactic Nucleus NGC 4051 Revealed by NICER
Hamaguchi, K.; Papadakis, I.; Kara, E. +6 more
Variability studies offer a compelling glimpse into black hole dynamics, and Neutron Star Interior Composition Explorer's (NICER's) remarkable temporal resolution propels us even further. NICER observations of an active galactic nucleus (AGN), NGC 4051, have charted the geometry of the emission region of the central supermassive black hole. Our in…
An Enigmatic PeVatron in an Area around H II Region G35.6‑0.5
Liu, B.; Liu, Y.; Zhang, Yong +294 more
Identifying Galactic PeVatrons (PeV particle accelerators) from ultrahigh-energy (UHE, >100 TeV) γ-ray sources plays a crucial role in revealing the origin of Galactic cosmic rays. The UHE source 1LHAASO J1857+0203u is suggested to be associated with HESS J1858+020, which may be attributed to the possible PeVatron candidate supernova remnant (S…
Observations of the Ultraviolet-bright Star III-60 in the Globular Cluster NGC 6723
Dixon, William V.
We have analyzed archival far-ultraviolet spectra of the UV-bright star III-60 in the globular cluster NGC 6723 obtained with the Far Ultraviolet Spectroscopic Explorer and the Cosmic Origins Spectrograph. We find that the star's photospheric parameters (effective temperature Teff = 44,800 ± 1200 K, surface gravity
An Exceptionally Powerful, Radiatively Driven Ultrafast Outflow in the Rapidly Accreting AGN RE J1034+396
Allen, Steven W.; Wilkins, Daniel R.; Taylor, Chloe S.
We report the analysis of ∼1 Ms of XMM-Newton observations of the rapidly accreting active galactic nucleus RE J1034+396. The 0.3–9 keV EPIC-pn spectra are well described by a model consisting of steep continuum emission from the corona accompanied by relativistically blurred reflection from a highly ionized accretion disk. The source is known to …
Prediction of Halo Coronal Mass Ejections Using SDO/HMI Vector Magnetic Data Products and a Transformer Model
Xu, Yan; Jing, Ju; Wang, Haimin +6 more
We present a transformer model, named DeepHalo, to predict the occurrence of halo coronal mass ejections (CMEs). Our model takes as input an active region (AR) and a profile, where the profile contains a time series of data samples in the AR that are collected 24 hr before the beginning of a day, and predicts whether the AR would produce a halo CM…