Search Publications
Do Interacting Coronal Mass Ejections Play a Role in Solar Energetic Particle Events?
Vourlidas, A.; Kahler, S. W.
Gradual solar energetic (E > 10 MeV) particle (SEP) events are produced in shocks driven by fast and wide coronal mass ejections (CMEs). With a set of western hemisphere 20 MeV SEP events, we test the possibility that SEP peak intensities, Ip, are enhanced by interactions of their associated CMEs with preceding CMEs (preCMEs) launched during th…
Can the magnetic field in the Orion arm inhibit the growth of instabilities in the bow shock of Betelgeuse?
Decin, L.; van Marle, A. J.; Meliani, Z.
Context. Many evolved stars travel through space at supersonic velocities, which leads to the formation of bow shocks ahead of the star where the stellar wind collides with the interstellar medium (ISM). Herschel observations of the bow shock of α-Orionis show that the shock is almost free of instabilities, despite being, at least in theory, subje…
Reconstructing the aqueous history within the southwestern Melas basin, Mars: Clues from stratigraphic and morphometric analyses of fans
Williams, Rebecca M. E.; Weitz, Catherine M.
New details of the aqueous history in the southwestern Melas Chasma elevated basin have been revealed from analysis of high-resolution image, topographic and spectral datasets. We have identified eleven fan-shaped landforms that reflect various depositional environments. A distinctive marker bed with inferred indurated aeolian bedforms is within t…
PKS 1510-089: a rare example of a flat spectrum radio quasar with a very high-energy emission
Barnacka, Anna; Moderski, Rafal; Behera, Bagmeet +2 more
Context. The blazar
The low-high-low trend of type III radio burst starting frequencies and solar flare hard X-rays
Kontar, Eduard P.; Vilmer, Nicole; Reid, Hamish A. S.
Aims: Using simultaneous X-ray and radio observations from solar flares, we investigate the link between the type III radio burst starting frequency and hard X-ray spectral index. For a proportion of events the relation derived between the starting height (frequency) of type III radio bursts and the electron beam velocity spectral index (dedu…
Orbital Monitoring of the AstraLux Large M-dwarf Multiplicity Sample
Henning, Thomas; Brandner, Wolfgang; Schlieder, Joshua +6 more
Orbital monitoring of M-type binaries is essential for constraining their fundamental properties. This is particularly useful in young systems, where the extended pre-main-sequence evolution can allow for precise isochronal dating. Here, we present the continued astrometric monitoring of the more than 200 binaries of the AstraLux Large Multiplicit…
An empirical mass-loss law for Population II giants from the Spitzer-IRAC survey of Galactic globular clusters
Dalessandro, E.; Valenti, E.; Rich, R. M. +4 more
Aims: The main aim of the present work is to derive an empirical mass-loss (ML) law for Population II stars in first and second ascent red giant branches.
Methods: We used the Spitzer InfraRed Array Camera (IRAC) photometry obtained in the 3.6-8 µm range of a carefully chosen sample of 15 Galactic globular clusters spanning the ent…
Direct Evidence of an Eruptive, Filament-hosting Magnetic Flux Rope Leading to a Fast Solar Coronal Mass Ejection
Chen, Bin; Gary, D. E.; Bastian, T. S.
Magnetic flux ropes (MFRs) are believed to be at the heart of solar coronal mass ejections (CMEs). A well-known example is the prominence cavity in the low corona that sometimes makes up a three-part white-light (WL) CME upon its eruption. Such a system, which is usually observed in quiet-Sun regions, has long been suggested to be the manifestatio…
Plasma physics of magnetic island coalescence during magnetic reconnection
Huang, Shiyong; Zhou, Meng; Deng, Xiaohua +2 more
A large-scale two-dimensional electromagnetic particle-in-cell simulation was employed to study the magnetic island coalescence/merging process during magnetic reconnection with guide field. The merged island after coalescence is characterized by strong core field and plasma density dip at the island center. We found that the core field enhancemen…
The HST view of the broad line region in low luminosity AGN
Capetti, A.; Balmaverde, B.
We analyze the properties of the broad line region (BLR) in low luminosity AGN by using HST/STIS spectra. We consider a sample of 24 nearby galaxies in which the presence of a BLR has been reported from their Palomar ground-based spectra. Following a widely used strategy, we used the [S II] doublet to subtract the contribution of the narrow emissi…