Search Publications
USco1621 B and USco1556 B: Two wide companions at the deuterium-burning mass limit in Upper Scorpius
Manjavacas, Elena; Rebolo, Rafael; Béjar, Víctor J. S. +6 more
Aims: Our objective is to identify analogues of gas giant planets, but located as companions at wide separations of very young stars. The main purpose is to characterise the binarity frequency and the properties of these substellar objects, and to elucidate their early evolutionary stages.
Methods: To identify these objects, we cross cor…
Statistical Analysis of Binary Stars from the Gaia Catalog Data Release 2
Zavada, Petr; Píška, Karel
We have developed a general statistical procedure for analysis of 2D and 3D finite patterns, which is applied to the data from recently released Gaia-ESA catalog DR2. The 2D analysis clearly confirms our former results on the presence of binaries in the former DR1 catalog. Our main objective is the statistical 3D analysis of DR2. For this, it is e…
PTFO 8-8695: Two Stars, Two Signals, No Planet
Winn, J. N.; Collins, K. A.; Jenkins, J. M. +13 more
PTFO 8-8695 (CVSO 30) is a star in the 7-10 million year old Orion OB1a cluster that shows brightness dips that resemble planetary transits. Although strong evidence against the planet hypothesis has been presented, the possibility remains debated in the literature. To obtain further clues, we inspected data from the NASA Transiting Exoplanet Surv…
Cometary avalanches as the cause of their violent outbursts - a new model of the phenomenon
Wesołowski, M.; Gronkowski, P.; Tralle, I.
The cometary outbursts are one of the most spectacular phenomena one can observe in the sky. They are associated with a sharp increase in the brightness of comets, which arises as a result of the ejection into space the dust, gas or even the fragments of outer layer of these celestial bodies core. Despite the existence of extensive observational m…
Constraining X-ray reflection in the low-luminosity AGN NGC 3718 using NuSTAR and XMM-Newton
Zezas, A.; Stern, D.; Bauer, F. E. +9 more
One distinctive feature of low-luminosity active galactic nuclei (LLAGNs) is the relatively weak reflection features they may display in the X-ray spectrum, which can result from the disappearance of the torus with decreasing accretion rates. Some material, however, must surround the active nucleus, i.e. the accretion flow itself and, possibly, a …
Globular cluster ejection, infall, and the host dark matter halo of the Pegasus dwarf galaxy
Beasley, Michael A.; Fahrion, Katja; Leaman, Ryan +10 more
Recent photometric observations revealed a massive, extended (MGC ≳ 105 M⊙; Rh ∼ 14 pc) globular cluster (GC) in the central region (D3D ≲ 100 pc) of the low-mass (M* ∼ 5 × 106 M⊙) dwarf irregular galaxy Pegasus. This massive GC offers a unique opportunity to s…
PIC Simulations of Microinstabilities and Waves at Near-Sun Solar Wind Perpendicular Shocks: Predictions for Parker Solar Probe and Solar Orbiter
Yang, Zhongwei; Liu, Ying D.; Guo, Fan +6 more
Microinstabilities and waves excited at moderate-Mach-number perpendicular shocks in the near-Sun solar wind are investigated by full particle-in-cell simulations. By analyzing the dispersion relation of fluctuating field components directly issued from the shock simulation, we obtain key findings concerning wave excitations at the shock front: (1…
Momentum and Pressure Balance of a Comet Ionosphere
Nilsson, H.; Goetz, C.; Richter, I. +3 more
We calculate the momentum flux and pressure of ions measured by the Ion Composition Analyzer (ICA) on the Rosetta mission at comet 67P/Churyumov-Gerasimenko. The total momentum flux stays roughly constant over the mission, but the contributions of different ion populations change depending on heliocentric distance. The magnetic pressure, calculate…
Kernel-phase analysis: Aperture modeling prescriptions that minimize calibration errors
Martinache, Frantz; Kammerer, Jens; N'Diaye, Mamadou +5 more
Context. Kernel phase is a data analysis method based on a generalization of the notion of closure phase, which was invented in the context of interferometry, but it applies to well corrected diffraction dominated images produced by an arbitrary aperture. The linear model upon which it relies theoretically leads to the formation of observable quan…
The Broad-lined Ic Supernova ZTF18aaqjovh (SN 2018bvw): An Optically Discovered Engine-driven Supernova Candidate with Luminous Radio Emission
Kulkarni, S. R.; Cenko, S. Bradley; Riddle, Reed +25 more
We present ZTF18aaqjovh (SN 2018bvw), a high-velocity ("broad-lined") stripped-envelope (Type Ic) supernova (Ic-BL SN) discovered in the Zwicky Transient Facility one-day cadence survey. ZTF18aaqjovh shares a number of features in common with engine-driven explosions: the photospheric velocity and the shape of the optical light curve are very simi…