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A search for X-ray reprocessing echoes in the power spectral density functions of AGN
Papadakis, I. E.; Emmanoulopoulos, D.; Dovčiak, M. +3 more
We present the results of a detailed study of the X-ray power spectral density (PSD) functions of 12 X-ray bright AGN, using almost all the archival XMM-Newton data. The total net exposure of the EPIC-pn light curves is larger than 350 ks in all cases (and exceeds 1 Ms in the case of 1H 0707-497). In a physical scenario in which X-ray reflection o…
Asteroseismic versus Gaia distances: A first comparison
De Ridder, J.; Eyer, L.; Aerts, C. +1 more
Context. The Kepler space mission led to a large number of high-precision time series of solar-like oscillators. Using a Bayesian analysis that combines asteroseismic techniques and additional ground-based observations, the mass, radius, luminosity, and distance of these stars can be estimated with good precision. This has given a new impetus to t…
Tracing p-mode Waves from the Photosphere to the Corona in Active Regions
Zhao, Junwei; Chen, Ruizhu; Felipe, Tobías +1 more
Atmosphere above sunspots is abundant with different types of waves. Among these waves are running penumbral waves in the chromosphere, quasi-periodic oscillations in the lower coronal loops, and recently reported running waves in sunspots’ photosphere, all of which were interpreted as magnetoacoustic waves by some authors. Are these waves in diff…
Planck intermediate results. XLI. A map of lensing-induced B-modes
Miville-Deschênes, M. -A.; Boulanger, F.; Bernard, J. -P. +178 more
The secondary cosmic microwave background (CMB) B-modes stem from the post-decoupling distortion of the polarization E-modes due to the gravitational lensing effect of large-scale structures. These lensing-induced B-modes constitute both a valuable probe of the dark matter distribution and an important contaminant for the extraction of the primary…
A GMRT study of Seyfert galaxies NGC 4235 and NGC 4594: evidence of episodic activity?
Singh, V.; Ishwara-Chandra, C. H.; Kharb, P. +3 more
Low-frequency observations at 325 and 610 MHz have been carried out for two `radio-loud' Seyfert galaxies, NGC 4235 and NGC 4594 (Sombrero galaxy), using the Giant Meterwave Radio Telescope (GMRT). The 610 MHz total intensity and 325-610 MHz spectral index images of NGC 4235 tentatively suggest the presence of a `relic' radio lobe, most likely fro…
Analysis of Coronal Rain Observed by IRIS, HINODE/SOT, and SDO/AIA: Transverse Oscillations, Kinematics, and Thermal Evolution
Kohutova, P.; Verwichte, E.
Coronal rain composed of cool plasma condensations falling from coronal heights along magnetic field lines is a phenomenon occurring mainly in active region coronal loops. Recent high-resolution observations have shown that coronal rain is much more common than previously thought, suggesting its important role in the chromosphere-corona mass cycle…
NuSTAR reveals the extreme properties of the super-Eddington accreting supermassive black hole in PG 1247+267
Harrison, F. A.; Stern, D.; Zhang, W. W. +26 more
PG1247+267 is one of the most luminous known quasars at z ~ 2 and is a strongly super-Eddington accreting supermassive black hole (SMBH) candidate. We obtained NuSTAR data of this intriguing source in December 2014 with the aim of studying its high-energy emission, leveraging the broad band covered by the new NuSTAR and the archival XMM-Newton dat…
Compositional and spatial variations in Titan dune and interdune regions from Cassini VIMS and RADAR
Malaska, Michael J.; Solomonidou, Anezina; Le Gall, Alice +4 more
Dunes cover about 15 % of Titan's visible surface, and represent one of the largest reservoirs of hydrocarbon solids on Titan (Rodriguez, S. et al. [2014]. Icarus 230, 168-179; Lopes, R.M.C. et al. [2016]. Icarus 270, 162-182.). Herein, we use data from the Cassini spacecraft to derive constraints on the compositional and regional variability of T…
Gaia Data Release 1. On-orbit performance of the Gaia CCDs at L2
Prusti, T.; Mora, A.; Brown, A. G. A. +19 more
The European Space Agency's Gaia satellite was launched into orbit around L2 in December 2013 with a payload containing 106 large-format scientific CCDs. The primary goal of the mission is to repeatedly obtain high-precision astrometric and photometric measurements of one thousand million stars over the course of five years. The scientific value o…
Rosetta lander Philae - Landing performance and touchdown safety assessment
Jurado, Eric; Ulamec, Stephan; Biele, Jens +2 more
This paper describes the simulation and analysis work on Rosetta lander Philae's touchdown dynamics which was done to support its Landing Site Selection Process. The simulation part consists of a numerical multi-body simulation to describe Philae's touchdown dynamics. Suitable performance metrics in conjunction with Monte Carlo trajectory data fro…