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Streaming classification of variable stars
Protopapas, P.; Zorich, L.; Pichara, K.
In the last years, automatic classification of variable stars has received substantial attention. Using machine learning techniques for this task has proven to be quite useful. Typically, machine learning classifiers used for this task require to have a fixed training set, and the training process is performed offline. Upcoming surveys such as the…
Simultaneous detection of an intrinsic absorber and a compact jet emission in the X-ray binary IGR J17091-3624 during a hard accretion state
Díaz Trigo, M.; Miller-Jones, J. C. A.; Migliari, S. +1 more
We present a detailed analysis of three XMM-Newton observations of the black hole low-mass X-ray binary IGR J17091-3624 taken during its 2016 outburst. Radio observations obtained with the Australia Telescope Compact Array indicate the presence of a compact jet during all observations. From the best X-ray data fit results, we concluded that the ob…
Rhea's subsurface probed by the Cassini radiometer: Insights into its thermal, structural, and compositional properties
Lellouch, E.; Le Gall, A.; Leyrat, C. +3 more
During its 13.5 years of operation around the Saturn system, the microwave radiometer incorporated in the Cassini RADAR observed Rhea at 2.2 cm during 9 flybys, with resolutions up to a tenth of Rhea's radius. We compare the antenna temperatures measured by this instrument to simulated data generated with the combination of thermal, radiative tran…
X-ray variability analysis of a large series of XMM-Newton +NuSTAR observations of NGC 3227
Turner, T. J.; Reeves, J. N.; Braito, V. +2 more
We present a series of X-ray variability results from a long XMM-Newton + NuSTAR campaign on the bright, variable AGN NGC 3227. We present an analysis of the light curves, showing that the source displays typically softer-when-brighter behaviour, although also undergoes significant spectral hardening during one observation which we interpret as du…
Realistic gravitational focusing of meteoroid streams
Vida, Denis; Moorhead, Althea V.; Clements, Tiffany D.
The number density and flux of a meteoroid stream is enhanced near a massive body due to the phenomenon known as gravitational focusing. The greatest enhancement occurs directly opposite the massive body from the stream radiant: as an observer approaches this location, the degree of focusing is unbound for a perfectly collimated stream. However, r…
A Random Forest Approach to Identifying Young Stellar Object Candidates in the Lupus Star-forming Region
Melton, Elizabeth
The identification and characterization of stellar members within a star-forming region are critical to many aspects of star formation, including formalization of the initial mass function, circumstellar disk evolution, and star formation history. Previous surveys of the Lupus star-forming region have identified members through infrared excess and…
The GAPS programme at TNG. XXVI. Magnetic activity in M stars: spectroscopic monitoring of AD Leonis
Scandariato, G.; Lanza, A. F.; Maldonado, J. +7 more
Context. Understanding stellar activity in M dwarfs is fundamental to improving our knowledge of the physics of stellar atmospheres and for planet search programmes. High levels of stellar activity (also frequently associated with flare events) can cause additional variations in the stellar emission that contaminate the signal induced by a planet …
Inference of Solar Rotation from Perturbations of Acoustic Mode Eigenfunctions
Roth, Markus; Schad, Ariane
Today's picture of the internal solar rotation rate profile results essentially from helioseismic analyses of frequency splittings of resonant acoustic waves. Here we present another, complementary estimation of the internal solar rotation rate using the perturbation of the shape of the acoustic waves. For this purpose, we extend a global heliosei…
First discovery of an ultra-cool white dwarf benchmark in common proper motion with an M dwarf
Hambly, N. C.; Harvey, E. J.; Lodieu, N. +5 more
Ultra-cool white dwarfs are among the oldest stellar remnants in the Universe. Their efficient gravitational settling and low effective temperatures are responsible for the smooth spectra they exhibit. For that reason, it is not possible to derive their radial velocities or to find the chemistry of the progenitors. The best that can be done is to …
Toward Solving the Puzzle: Dissecting the Complex Merger A521 with Multiwavelength Data
Kim, Jae-Woo; Jee, M. James; Finner, Kyle +3 more
A521 has been a subject of extensive panchromatic studies from X-ray to radio. The cluster possesses a number of remarkable features, including a bright radio relic with a steep spectrum, more than three distinct galaxy groups forming a filament, and two disturbed X-ray peaks at odds with the distant position and tilted orientation of the radio re…