Binary Stars among Cataclysmic Variables. II. Nova WZ Sagittae: a Possible Radiator of Gravitational Waves.

1962 ◽  
Vol 136 ◽  
pp. 312 ◽  
Author(s):  
Robert P. Kraft ◽  
Jon Mathews ◽  
Jesse L. Greenstein
2019 ◽  
Vol 631 ◽  
pp. A118 ◽  
Author(s):  
Fabian Göttgens ◽  
Tim-Oliver Husser ◽  
Sebastian Kamann ◽  
Stefan Dreizler ◽  
Benjamin Giesers ◽  
...  

Aims. Globular clusters produce many exotic stars due to a much higher frequency of dynamical interactions in their dense stellar environments. Some of these objects were observed together with several hundred thousand other stars in our MUSE survey of 26 Galactic globular clusters. Assuming that at least a few exotic stars have exotic spectra (i.e. spectra that contain emission lines), we can use this large spectroscopic data set of over a million stellar spectra as a blind survey to detect stellar exotica in globular clusters. Methods. To detect emission lines in each spectrum, we modelled the expected shape of an emission line as a Gaussian curve. This template was used for matched filtering on the differences between each observed 1D spectrum and its fitted spectral model. The spectra with the most significant detections of Hα emission are checked visually and cross-matched with published catalogues. Results. We find 156 stars with Hα emission, including several known cataclysmic variables (CV) and two new CVs, pulsating variable stars, eclipsing binary stars, the optical counterpart of a known black hole, several probable sub-subgiants and red stragglers, and 21 background emission-line galaxies. We find possible optical counterparts to 39 X-ray sources, as we detected Hα emission in several spectra of stars that are close to known positions of Chandra X-ray sources. This spectral catalogue can be used to supplement existing or future X-ray or radio observations with spectra of potential optical counterparts to classify the sources.


Author(s):  
Franyelit María Suárez Carreño ◽  
Luis Dionisio Rosales

Introduction :A review is made of gravitational waves, their simulation and the methods used for their definitive detection in 2015. A comparison of electromagnetic waves with gravitational waves and the main technological efforts made over decades for their detection is presented. Objective:is to detect OG from massive black holes and galactic and extragalactic binary stars in a frequency range of 10-4 to 10-1 Hz. Materials and methods: Numerical methods used in its simulation are specified, emphasizing computational techniques used in recent years. Results:The boundary is placed at x = 2/3 and the parameters are used for the simulations shown in figures 3 and 4: number of points of the angular mesh Nq = Np = Nξ = 45, and for the radial mesh Nx = 100 , A = 10-3, Ra = 4, Rb = 7. Discussion:The simulations were carried out with a code programmed in FORTRAN 90 and run under the LINUX free software platform. The figures were generated with the Dx plotter under LINUX environment, allowed to evaluate the respective equations and give a satisfactory answer to the proposed objectives. Conclusions:it was possible to conclude that the detection of gravitational waves is possible, however it is necessary to improve the sensitivity, which will allow the detection of new events collecting information about sources three times more distant, and increasing the probability of detection.


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