On the origin of two unidentified radio/X-ray sources discovered with XMM-Newton

We aim at clarifying the nature of the emission of two spatially related unidentified X-ray sources detected with XMM-Newton telescope at intermediate-low Galactic latitude. Observations reveal a point-like source aligned with elongated diffuse emission. The X-ray spectra are best-fitted by absorbed power laws with photon indices ~1.7 for the point-like and ~2.0 for the extended one. Both sources show nonthermal radio-continuum counterparts that might indicate a physical association. From the available data, we did not detect variability on the point-like source in several timescales. Two possible scenarios are analyzed: first, based on HI line absorption, assuming a Galactic origin, we infer a distance upper bound of <2 kpc, which poses a constraint on the height over the Galactic plane of <200 pc and on the linear size of the system of 10^32 erg/s and >7.5 x 10^32 erg/s, for the point-like and extended sources, respectively; second, an extra-Galactic nature is discussed, where the point-like source might be the core of a radio galaxy and the extended source its lobe. In this case, we compare derived fluxes, spectral indices, and spatial correlation with those typical from the radio galaxy population, showing the feasibility of this alternative astrophysical scenario. From the available observational evidence, we suggest that the most promising scenario to explain the nature of these sources is a system consisting of a one-sided radio galaxy, where the point-like source is an active galactic nucleus and the extended source corresponds to the emission from its lobe. Other possibilities include a PSR/PWN origin, where the radio/X-ray emission originates from the synchrotron cooling of relativistic particles in the PSR magnetic field or a casual alignment between two unrelated sources, such as an AGN core and a Galactic X-ray blob.Comment: 6 pages, 2 figures. Accepted for publication in Astronomy and Astrophysics (A&A

The blockchain role in ethical data acquisition and provisioning

The collection of personal data through mobile applications and IoT devices represents the core business of many corporations. From one hand, users are losing control about the property of their data and rarely are conscious about what they are sharing with whom; from the other hand, laws like the European General Data Protection Regulation try to bring data control and ownership back to users. In this paper we discuss the possible impact of the blockchain technology in building independent and resilient data management systems able to ensure data ownership and traceability. The use of this technology could play a major role in creating a transparent global market of aggregated personal data where voluntary acquisition is subject to clear rules and some forms of incentives, making not only the process ethical but also encouraging the sharing of high quality sensitive data

An inference system for relationships between spatio-temporal granularities

Temporal, spatial, and spatio-temporal granularities allow one to qualify classical data locating them in time and space. In order to compare data qualified with different granularities and associate data to different granularities, it is necessary to know how the involved granularities are related. However, the explicit calculation of these relationships may be heavy from a computational point of view. Thus, in this paper, we propose an inference system for inferring definitely valid relationships starting from a set of already known valid relationships without to calculate them explicitly. We will prove the soundness and completeness of the system

A global model of cometary tail disconnection events triggered by solar wind magnetic variations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94832/1/jgra18723.pd

Publishing artificial intelligence research papers: A tale of three journals

With the growth in Artificial Intelligence in Medicine (AIM) research and the plethora of informatics journals, there is some confusion where to direct an AIM-related manuscript for peer review and possible pub- lication. As editors for three Elsevier biomedical informatics journals that publish AI-related papers, plus the publisher who oversees all three of these journals, we are aware of such confusion and felt it would be helpful to provide some guidance to prospective authors. Accordingly, we present this joint editorial that is being published in all three of our journals. Although there is some overlap among the types of papers that we publish, we offer here some advice on how best to select a preferred publication venue for your medical AI research papers

Publishing Artificial Intelligence Research Papers: A Tale of Three Journals

With the growth in Artificial Intelligence in Medicine (AIM) research and the plethora of informatics journals, there is some confusion where to direct an AIM-related manuscript for peer review and possible publication. As editors for three Elsevier biomedical informatics journals that publish AI-related papers, plus the publisher who oversees all three of these journals, we are aware of such confusion and felt it would be helpful to provide some guidance to prospective authors. Accordingly, we present this joint editorial that is being published in all three of our journals. Although there is some overlap among the types of papers that we publish, we offer here some advice on how best to select a preferred publication venue for your medical AI research papers

Hall Effect in the coma of 67P/Churyumov-Gerasimenko

Magnetohydrodynamics simulations have been carried out in studying the solar wind and cometary plasma interactions for decades. Various plasma boundaries have been simulated and compared well with observations for comet 1P/Halley. The Rosetta mission, which studies comet 67P/Churyumov-Gerasimenko, challenges our understanding of the solar wind and comet interactions. The Rosetta Plasma Consortium observed regions of very weak magnetic field outside the predicted diamagnetic cavity. In this paper, we simulate the inner coma with the Hall magnetohydrodynamics equations and show that the Hall effect is important in the inner coma environment. The magnetic field topology becomes complex and magnetic reconnection occurs on the dayside when the Hall effect is taken into account. The magnetic reconnection on the dayside can generate weak magnetic filed regions outside the global diamagnetic cavity, which may explain the Rosetta Plasma Consortium observations. We conclude that the substantial change in the inner coma environment is due to the fact that the ion inertial length (or gyro radius) is not much smaller than the size of the diamagnetic cavity.Comment: 23 pages, 6 figur

Study of the April 20, 2007 CME-Comet Interaction Event with an MHD Model

This study examines the tail disconnection event on April 20, 2007 on comet 2P/Encke, caused by a coronal mass ejection (CME) at a heliocentric distance of 0.34 AU. During their interaction, both the CME and the comet are visible with high temporal and spatial resolution by the STEREO-A spacecraft. Previously, only current sheets or shocks have been accepted as possible reasons for comet tail disconnections, so it is puzzling that the CME caused this event. The MHD simulation presented in this work reproduces the interaction process and demonstrates how the CME triggered a tail disconnection in the April 20 event. It is found that the CME disturbs the comet with a combination of a $180^\circ$ sudden rotation of the interplanetary magnetic field (IMF), followed by a $90^\circ$ gradual rotation. Such an interpretation applies our understanding of solar wind-comet interactions to determine the \textit{in situ} IMF orientation of the CME encountering Encke.Comment: 13 pages, 3 figures, accepted by the ApJ Letter