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Characterization of the umbra-penumbra boundary by the vertical component of the magnetic field. Analysis of ground-based data from the GREGOR Infrared Spectrograph
Bello González, N.; Schlichenmaier, R.; Lindner, P.
Context. The vertical component of the magnetic field was found to reach a constant value at the boundary between penumbra and umbra of stable sunspots in a recent statistical study of Hinode/SP data. This finding has profound implications as it can serve as a criterion to distinguish between fundamentally different magneto-convective modes operat…
Shear Measurement Bias Due to Spatially Varying Spectral Energy Distributions in Galaxies
Burchat, Patricia R.; Meyers, Joshua E.; Kamath, Sowmya +1 more
Galaxy color gradients (CGs)—I.e., spectral energy distributions that vary across the galaxy profile—will impact galaxy shape measurements when the modeled point-spread function (PSF) corresponds to that for a galaxy with spatially uniform color. This paper describes the techniques and results of a study of the expected impact of galaxy CGs on wea…
Mechanochemical synthesis of aromatic infrared band carriers. The top-down chemistry of interstellar carbonaceous dust grain analogues
Engrand, C.; Dartois, E.; Charon, E. +2 more
Context. Interstellar space hosts nanometre- to micron-sized dust grains, which are responsible for the reddening of stars in the visible. The carbonaceous-rich component of these grain populations emits in infrared bands that have been observed remotely for decades with telescopes and satellites. They are a key ingredient of Galactic radiative tr…
High-resolution spectroscopy of the high-velocity hot post-AGB star IRAS 18379-1707 (LS 5112)
Hubrig, S.; Parthasarathy, M.; Ikonnikova, N. P. +2 more
The high-resolution (R∼ 48 000) optical spectrum of the B-type supergiant LS 5112, identified as the optical counterpart of the post-AGB candidate IRAS 18379-1707 is analysed. We report the detailed identifications of the observed absorption and emission features in the wavelength range 3700-9200 Å for the first time. The absorption line spectrum …
X-ray properties of high-richness CAMIRA clusters in the Hyper Suprime-Cam Subaru Strategic Program field
Oguri, Masamune; Fujimoto, Ryuichi; Okabe, Nobuhiro +13 more
We present the first results of a pilot X-ray study of 37 rich galaxy clusters at 0.1 < z < 1.1 in the Hyper Suprime-Cam Subaru Strategic Program field. Diffuse X-ray emissions from these clusters were serendipitously detected in the XMM-Newton fields of view. We systematically analyze X-ray images of 37 clusters and emission spectra of a su…
Variable stars in the field of intermediate-age open cluster NGC 559
Joshi, Y. C.; John, Ancy A.; Maurya, J. +3 more
This work presents the first long-term photometric variability survey of the intermediate-age open cluster NGC 559. Time series V-band photometric observations on 40 nights taken over more than 3 yr with three different telescopes are analysed to search for variable stars in the cluster. We investigate the data for the periodicity analysis and rev…
Cut-off features in interplanetary solar radio type IV emission
Pohjolainen, Silja; Talebpour Sheshvan, Nasrin
Solar radio type IV bursts can sometimes show directivity, so that no burst is observed when the source region in located far from the solar disk center. This has recently been verified also from space observations, at decameter wavelengths, using a 3D-view to the Sun with STEREO and Wind satellites. It is unclear whether the directivity is caused…
NaCo polarimetric observations of Sz 91 transitional disc: a remarkable case of dust filtering
Villaver, Eva; Pinte, Christophe; Zurlo, Alice +10 more
We present polarized light observations of the transitional disc around Sz 91 acquired with VLT/NaCo at H (1.7µm) and Ks (2.2µm) bands. We resolve the disc and detect polarized emission up to ∼0.5 arcsec (∼80 au) along with a central cavity at both bands. We computed a radiative transfer model that accounts for the main char…
Analysis of spiral structure in the accretion disc of the nova-like cataclysmic variable EC21178-5417
Groot, P. J.; Woudt, P. A.; Ruiz-Carmona, R. +1 more
We present an extensive Doppler tomography study of the eclipsing nova-like EC21178-5417, which exhibits the classic accretion disc signature in the form of double-peak emission lines in its spectrum. Doppler tomograms confirm the presence of a strong, two-armed spiral pattern visible in the majority of the spectral lines studied. This makes EC211…
Variability in Protoplanetary Nebulae: VII. Light-curve Studies of Five Medium-bright, Oxygen-rich, or Mixed-chemistry Post-AGB/Post-RGB Objects
Lu, Wenxian; Volk, Kevin; Hrivnak, Bruce J. +3 more
We have monitored over a 10-year interval the light variations of five evolved stars with very large mid-infrared excesses. All five objects appear to have oxygen-rich or mixed oxygen-rich and carbon-rich chemistries. They all vary in light: four over a small range of ∼0.2 mag and the fifth over a larger range of ∼0.7 mag. Spectral types range fro…