Search Publications
Limits on the presence of planets in systems with debris discs: HD 92945 and HD 107146
Henning, T.; Messina, S.; D'Orazi, V. +38 more
Recent observations of resolved cold debris discs at tens of au have revealed that gaps could be a common feature in these Kuiper-belt analogues. Such gaps could be evidence for the presence of planets within the gaps or closer in near the edges of the disc. We present SPHERE observations of HD 92945 and HD 107146, two systems with detected gaps. …
A Perspective on the Scaling of Magnetosheath Turbulence and Effects of Bow Shock Properties
Voitcu, Gabriel; Echim, Marius; Teodorescu, Eliza
We analyze magnetic field data from two magnetosheath crossings, representative of a larger collection of similar cases in the database of the Cluster spacecraft. We apply a novel data analysis method to identify the power-law behavior of the structure functions and to find the validity range of the power-law scaling. We validate the technique wit…
The BIG X-ray tail
Churazov, Eugene; Jones, Christine; Fossati, Matteo +9 more
Galaxy clusters grow primarily through the continuous accretion of group-scale haloes. Group galaxies experience preprocessing during their journey into clusters. A star-bursting compact group, the Blue Infalling Group (BIG), is plunging into the nearby cluster A1367. Previous optical observations reveal rich tidal features in the BIG members, and…
IKT 16 aka PSR J0058-7218: discovery of a 22 ms energetic rotation-powered pulsar in the Small Magellanic Cloud
Haberl, F.; Tiengo, A.; Filipović, M. D. +5 more
We report here on the discovery with XMM-Newton of pulsations at 22 ms from the central compact source associated with IKT 16, a supernova remnant in the Small Magellanic Cloud (SMC). The measured spin period and spin period derivative correspond to 21.7661076(2) ms and 2.9(3) × 10-14 s s-1, respectively. Assuming standard sp…
Eclipsing Binaries in the Open Cluster Ruprecht 147. IV: The Active Triple System EPIC 219511354
Torres, Guillermo; Vanderburg, Andrew; Gaidos, Eric +2 more
We report follow-up spectroscopic observations of the 1.62 day, K-type, detached, active, near-circular, double-lined eclipsing binary EPIC 219511354 in the open cluster Ruprecht 147, identified previously on the basis of photometric observations from the Kepler/K2 mission. This is the fourth eclipsing system analyzed in this cluster. A combined a…
The 2017 May 20 stellar occultation by the elongated centaur (95626) 2002 GZ32
Mottola, S.; Charmandaris, V.; Alvarez-Candal, A. +56 more
We predicted a stellar occultation of the bright star Gaia DR1 4332852996360346368 (UCAC4 385-75921) (mV = 14.0 mag) by the centaur 2002 GZ32 for 2017 May 20. Our latest shadow path prediction was favourable to a large region in Europe. Observations were arranged in a broad region inside the nominal shadow path. Series of ima…
Phase Modeling of the TRAPPIST-1 Planetary Atmospheres
Kane, Stephen R.; Fauchez, Thomas; Selsis, Franck +2 more
Transiting compact multiplanet systems provide many unique opportunities to characterize the planets, including studies of size distributions, mean densities, orbital dynamics, and atmospheric compositions. The relatively short orbital periods in these systems ensure that events requiring specific orbital locations of the planets (such as primary …
A Weakening Compton Hump and Soft X-Ray Excess Detected in the Seyfert 1 Galaxy MCG -02-58-22
Laha, Sibasish; Ghosh, Ritesh
We have carried out an extensive X-ray spectral study of the bare Seyfert 1 galaxy MCG -02-58-22 to ascertain the nature of the X-ray reprocessing media using observations from Suzaku (2009) and simultaneous observations from XMM-Newton and NuSTAR (2016). The most significant results of our investigation are as follows. (1) The primary X-ray emiss…
Broadband Modeling of Low-luminosity Active Galactic Nuclei Detected in Gamma Rays
Prince, Raj; Tomar, Gunjan; Gupta, Nayantara
Low-luminosity active galactic nuclei are more abundant and closer to us than the luminous ones but harder to explore as they are faint. We have selected the four sources, NGC 315, NGC 4261, NGC 1275, and NGC 4486, which have been detected in γ-rays by Fermi-LAT. We have compiled their long-term radio, optical, X-ray data from different telescopes…
Properties of the C II 1334 Å Line in Coronal Hole and Quiet Sun as Observed by IRIS
Tripathi, Durgesh; Upendran, Vishal
Coronal holes (CHs) have subdued intensity and net blueshifts when compared to the quiet Sun (QS) at coronal temperatures. At transition region temperatures, such differences are obtained for regions with identical absolute photospheric magnetic flux density (∣B∣). In this work, we use spectroscopic measurements of the C II 1334 Å line from the In…