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Physical Conditions in Shocked Interstellar Gas Interacting with the Supernova Remnant IC 443
Jenkins, Edward B.; Ritchey, Adam M.; Federman, S. R. +3 more
We present the results of a detailed investigation into the physical conditions in interstellar material interacting with the supernova remnant (SNR) IC 443. Our analysis is based on a comprehensive examination of high-resolution far-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope of tw…
The EXOD search for faint transients in XMM-Newton observations: Method and discovery of four extragalactic Type I X-ray bursters
Webb, N. A.; van Leeuwen, J.; Pastor-Marazuela, I. +1 more
Context. The observations carried out with XMM-Newton have produced a very extensive X-ray source catalogue in which the standard pipeline determines the variability of sufficiently bright sources through χ2 and fractional variability tests. Faint sources, however, are not automatically checked for variability, and this means that faint…
The Nonstandard Properties of a "Standard" PWN: Unveiling the Mysteries of PWN G21.5-0.9 Using Its IR and X-Ray Emission
Gelfand, Joseph D.; Temim, Tea; Slane, Patrick O. +3 more
The evolution of a pulsar wind nebula (PWN) depends on properties of the progenitor star, supernova, and surrounding environment. As some of these quantities are difficult to measure, reproducing the observed dynamical properties and spectral energy distribution (SED) with an evolutionary model is often the best approach to estimating their values…
Data-Driven Classification of Coronal Hole and Streamer Belt Solar Wind
Macneil, Allan R.; Owens, Mathew; Bloch, Téo +2 more
We present two new solar wind origin classification schemes developed independently using unsupervised machine learning. The first scheme aims to classify solar wind into three types: coronal-hole wind, streamer-belt wind, and `unclassified' which does not fit into either of the previous two categories. The second scheme independently derives thre…
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…