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Carrington cycle 24: the solar chromospheric emission in a historical and stellar perspective
Schmitt, J. H. M. M.; Schröder, K. -P.; Mittag, M. +3 more
We present the solar S-index record of cycle 24, obtained by the Telescopio Internacional de Guanajuato, Robotico Espectroscopico robotic telescope facility and its high-resolution spectrograph HEROS (R ≈ 20 000), which measures the solar chromospheric Ca II H&K line emission by using moonlight. Our calibration process uses the same set of sta…
Complex diffuse emission in the z = 0.52 cluster PLCK G004.5-19.5
Mernier, F.; Brunetti, G.; Röttgering, H. J. A. +4 more
We present radio observations of the galaxy cluster PLCK G004.5-19.5 (z = 0.52) using the Giant Metrewave Radio Telescope at 150 MHz, 325 MHz, and 610 MHz. We find an unusual arrangement of diffuse radio emission in the center and periphery of the cluster, as well as several radio galaxies with head-tail emission. A patch of peripheral emission re…
Probing Large Galaxy Halos at Z ∼ 0 with Automated Lyα-absorption Matching
Wakker, Bart P.; French, David M.
We present initial results from an ongoing large-scale study of the circumgalactic medium in the nearby Universe ({cz} ≤slant 10,000 {km} {{{s}}}-1), using archival Cosmic Origins Spectrograph spectra of background quasi-stellar objects. This initial sample contains 33 sightlines chosen for their proximity to large galaxies (D≥slant 25 …
Determination of robust metallicities for metal-rich red giant branch stars. An application to the globular cluster NGC 6528
Liu, C.; Primas, F.; Feltzing, S. +1 more
Context. The study of the Milky Way relies on our ability to interpret the light from stars correctly. With the advent of the astrometric ESA mission Gaia we will enter a new era where the study of the Milky Way can be undertaken on much larger scales than currently possible. In particular we will be able to obtain full 3D space motions of red gia…
History of Mars Atmosphere Observations
Christensen, Philip R.; Lemmon, Mark T.; Withers, Paul +2 more
CCD astrometric observations of Amalthea and Thebe in the Gaia era
Colas, F.; Saquet, E.; Robert, V. +1 more
In the framework of the 2014-2015 campaign of mutual events, we observed Jupiter's inner satellites Amalthea (JV) and Thebe (JXIV). We focused on estimating whether the positioning accuracy determined from direct astrometry could compete with that derived from photometric observations of eclipses, for dynamical purposes. We present the analysis of…
Comparison of Gaia and asteroseismic distances
Roth, M.; Örtel, S.; Yıldız, M. +1 more
Asteroseismology provides fundamental properties (mass, radius and effective temperature) of solar-like oscillating stars using so-called scaling relations. These properties allow the computation of the asteroseismic distance of stars. We compare the asteroseismic distances with the recently released Gaia distances for 74 stars studied in Yıldız e…
Computation of the Transmitted and Polarized Scattered Fluxes by the Exoplanet HD 189733b in X-Rays
Marin, Frédéric; Grosso, Nicolas
Thousands of exoplanets have been detected, but only one exoplanetary transit was potentially observed in X-rays from HD 189733A. What makes the detection of exoplanets so difficult in this band? To answer this question, we run Monte-Carlo radiative transfer simulations to estimate the amount of X-ray flux reprocessed by HD 189733b. Despite its ex…
Multi-spacecraft studies of the auroral acceleration region: From cluster to nanosatellites
Sadeghi, S.; Emami, M. R.
This paper discusses the utilization of multiple Cubesats in various formations for studies in the auroral acceleration region. The focus is on the quasi-static properties, spatio-temporal features, electric potential structures, field-aligned currents, and their relationships, all of which are fundamentally important for an understanding of the m…
Far Ultraviolet Spectroscopy of Old Novae. II. RR Pic, V533 Her, and DI Lac
Sion, Edward M.; Godon, Patrick; Jones, Liam
The old novae V533 Her (Nova Her 1963), DI Lac (Nova Lac 1910), and RR Pic (Nova Pic 1891) are in (or near) their quiescent stage, following their nova explosions, and continue to accrete at a high rate in the aftermath of their explosions. They exhibit continua that are steeply rising into the FUV, as well as absorption lines and emission lines o…