Search Publications
Strongest Coronal Magnetic Fields in Solar Cycles 23 and 24: Probing, Statistics, and Implications
Fleishman, Gregory D.; Anfinogentov, Sergey A.; Fedenev, Viktor V.
A strong coronal magnetic field, when present, manifests itself as bright microwave sources at high frequencies produced by the gyroresonant (GR) emission mechanism in thermal coronal plasma. The highest frequency at which this emission is observed is proportional to the absolute value of the strongest coronal magnetic field on the line of sight. …
The variable source of the plasma sheet during a geomagnetic storm
Asamura, K.; Kistler, L. M.; Mouikis, C. G. +8 more
Both solar wind and ionospheric sources contribute to the magnetotail plasma sheet, but how their contribution changes during a geomagnetic storm is an open question. The source is critical because the plasma sheet properties control the enhancement and decay rate of the ring current, the main cause of the geomagnetic field perturbations that defi…
Interaction of a coronal mass ejection and a stream interaction region: A case study
Geyer, Paul; Dumbović, Mateja; Temmer, Manuela +3 more
We investigated the interaction of a coronal mass ejection (CME) and a coronal hole (CH) in its vicinity using remote-sensing and 1 AU in situ data. We used extreme-ultraviolet images and magnetograms to identify coronal structures and coronagraph images to analyze the early CME propagation. The Wind spacecraft and the Advanced Composition Explore…
X-Ray Studies of the Pulsar PSR J1420-6048 and Its TeV Pulsar Wind Nebula in the Kookaburra Region
Woo, Jooyun; An, Hongjun; Mori, Kaya +4 more
We present a detailed analysis of broadband X-ray observations of the pulsar PSR J1420-6048 and its wind nebula (PWN) in the Kookaburra region with Chandra, XMM-Newton, and NuSTAR. Using the archival XMM-Newton and new NuSTAR data, we detected 68 ms pulsations of the pulsar and characterized its X-ray pulse profile, which exhibits a sharp spike an…
Asteroseismic Modeling of 1153 Kepler Red Giant Branch Stars: Improved Stellar Parameters with Gravity-mode Period Spacings and Luminosity Constraints
Bi, Shaolan; Li, Yaguang; Bedding, Timothy R. +2 more
This paper reports the estimated stellar parameters of 1153 Kepler red giant branch stars determined with asteroseismic modeling. We use radial-mode oscillation frequencies, gravity-mode period spacings, Gaia luminosities, and spectroscopic data to characterize these stars. Compared with previous studies, we find that the two additional observed c…
HST PanCET programme: a flat optical transmission spectrum for the Hot Jupiter WASP-101b
Mikal-Evans, Thomas; Sing, David K.; López-Morales, Mercedes +10 more
We present an optical transmission spectrum of the hot Jupiter WASP-101b. We observed three primary transits with Hubble Space Telescope (HST)/Space Telescope Imaging Spectrograph, covering a wavelength range from 0.3 to 1 $\mu$m. The observations suffer from significant systematics that we model using Gaussian Processes. Kernel selection for the …
Simulating the charging of isolated free-falling masses from TeV to eV energies: Detailed comparison with LISA Pathfinder results
Hollington, D.; Wass, P. J.; Sumner, T. J. +1 more
A model is presented that explains the charging rate of the LISA Pathfinder test masses by the interplanetary cosmic ray environment. The model incorporates particle-tracking from TeV to eV energies using a combination of GEANT4 and a custom low-energy particle generation and tracking code. The electrostatic environment of the test mass is simulat…
Mid-IR spectral properties of different surfaces of silicate mixtures before and after excimer laser irradiation
Hiesinger, Harald; Helbert, Jörn; Weber, Iris +6 more
The behaviour of the Christiansen feature (CF) and the Reststrahlen bands (RBs) in mid-infrared (IR) reflectance spectra on various silicate mixtures as pressed pellets and powders was investigated in high-vacuum. In addition, the influence of micrometeorite bombardment simulated with an excimer laser was studied. The mixtures cover a wide range o…
MagAO-X and HST High-contrast Imaging of the AS209 Disk at Hα
Edwards, Suzan; Zhou, Yifan; Bae, Jaehan +22 more
The detection of emission lines associated with accretion processes is a direct method for studying how and where gas giant planets form, how young planets interact with their natal protoplanetary disk, and how volatile delivery to their atmosphere takes place. Hα (λ = 0.656 µm) is expected to be the strongest accretion line observable from …
A Coronal Mass Ejection Source Region Catalog and Their Associated Properties
Pant, Vaibhav; Banerjee, Dipankar; Patel, Ritesh +4 more
The primary objective of this study is to connect coronal mass ejections (CMEs) to their source regions, primarily to create a CME source region catalog, and secondarily to probe the influence that the source regions have on the different statistical properties of CMEs. We create a source region catalog for 3327 CMEs from 1998 to 2017, thus captur…