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Visibility Interpolation in Solar Hard X-Ray Imaging: Application to RHESSI and STIX
Massa, Paolo; Piana, Michele; Perracchione, Emma +1 more
Space telescopes for solar hard X-ray imaging provide observations made of sampled Fourier components of the incoming photon flux. The aim of this study is to design an image reconstruction method relying on enhanced visibility interpolation in the Fourier domain. The interpolation-based method is applied to synthetic visibilities generated by mea…
Kepler K2 Campaign 9 - I. Candidate short-duration events from the first space-based survey for planetary microlensing
Poleski, R.; Mao, S.; Penny, M. T. +6 more
We present the first short-duration candidate microlensing events from the Kepler K2 mission. From late April to early July 2016, Campaign 9 of K2 obtained high temporal cadence observations over a 3.7 deg2 region of the Galactic bulge. Its primary objectives were to look for evidence of a free-floating planet (FFP) population using mic…
Evaluation of a potential field source surface model with elliptical source surfaces via ballistic back mapping of in situ spacecraft data
Wimmer-Schweingruber, R. F.; Kruse, M.; Heidrich-Meisner, V.
Context. The potential field source surface (PFSS) model is an important tool that helps link the solar coronal magnetic field to the solar wind. Due to its simplicity, it allows for predictions to be computed rapidly and requires little input data, though at the cost of reduced accuracy compared to more complex models. So far, PFSS models have al…
Large eddy simulations of the Martian convective boundary layer: Towards developing a new planetary boundary layer scheme
Mischna, Michael A.; Karatekin, Özgür; Senel, Cem Berk +5 more
The grid resolutions typically employed in atmospheric global circulation and mesoscale models are not sufficient to explicitly resolve the turbulence processes within the planetary boundary layer (PBL). turbulent fluxes are, therefore, fully parameterized in those models, based on empirical relationships for the mixing length scale using PBL sche…
A shock near the virial radius of the Perseus Cluster
Simionescu, A.; Kaastra, J. S.; Zhang, X. +6 more
Context. Previous X-ray studies of the Perseus Cluster, consisting of 85 Suzaku pointings along eight azimuthal directions, revealed a particularly steep decrease in the projected temperature profile near the virial radius (∼r200) towards the northwest (NW).
Aims: To further explore this shock candidate, another 4 Suzaku observatio…
The first heavy-metal hot subdwarf composite binary SB 744
Bastian, A.; Németh, P.; Vos, J. +1 more
Aims: The long-period sdOB+G1V type spectroscopic binary SB 744 reveals strong lines of fluorine and lead in the optical spectrum of the sdOB star and subsolar metallicity in the G1V companion thanks to a radial velocity follow-up study. Using high-quality observations and Gaia astrometric data, we aim to measure the chemical composition and …
The CARMA-NRO Orion Survey: Filament Formation via Collision-induced Magnetic Reconnection—the Stick in Orion A
Mairs, Steve; Nakamura, Fumitaka; Klessen, Ralf S. +13 more
A unique filament is identified in the Herschel maps of the Orion A giant molecular cloud. The filament, which we name the Stick, is ruler-straight and at an early evolutionary stage. Transverse position-velocity diagrams show two velocity components closing in on the Stick. The filament shows consecutive rings/forks in C18O (1-0) chann…
Hamilton's Object - a clumpy galaxy straddling the gravitational caustic of a galaxy cluster: constraints on dark matter clumping
Griffiths, Richard E.; Villforth, Carolin; Wagner, Jenny +3 more
We report the discovery of a 'folded' gravitationally lensed image, 'Hamilton's Object', found in a HST image of the field near the active galactic nucleus SDSS J223010.47-081017.8 (which has redshift 0.62). The lensed images are sourced by a galaxy at a spectroscopic redshift of 0.8200 ± 0.0005 and form a fold configuration on a caustic caused by…
The nearby magnetic cool DZ white dwarf PM J08186-3110
Vennes, Stéphane; Allard, Nicole F.; Kawka, Adela +2 more
We present an analysis of photometric, spectroscopic, and spectropolarimetric data of the nearby, cool, magnetic DZ white dwarf PM J08186-3110. High-dispersion spectra show the presence of Zeeman splitted spectral lines due to the presence of a surface average magnetic field of 92 kG. The strong magnesium and calcium lines show extended wings shap…
Metallicity and X-ray luminosity variations in NGC 922
Zezas, A.; Wolter, A.; Fruscione, A. +3 more
We present a systematic study of the metallicity variations within the collisional ring galaxy NGC 922 based on long-slit optical spectroscopic observations. We find a metallicity difference between star-forming regions in the bulge and the ring, with metallicities ranging from almost solar to significantly sub-solar ( $\rm {[12+\log (O/H)]\sim 8.…