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J/A+A/610/A61    SGR 1806-20 & SGR 1900+14 quasi-periodic oscill. (Pumpe+, 2018)

Search for quasi periodic signals in magnetar giant flares. Bayesian inspection of SGR 1806-20 and SGR 1900+14. Pumpe D., Gabler M., Steininger T., Ensslin T.A. <Astron. Astrophys. 610, A61 (2018)> =2018A&A...610A..61P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; X-ray sources ; Spectroscopy Keywords: X-rays: bursts - stars: magnetars - stars: oscillations - stars: neutron - methods: statistical Abstract: Quasi-periodic oscillations (QPOs) discovered in the decaying tails of giant flares of magnetars are believed to be torsional oscillations of neutron stars. These QPOs have a high potential to constrain properties of high-density matter. In search for quasi-periodic signals, we study the light curves of the giant flares of SGR 1806-20 and SGR 1900+14, with a non-parametric Bayesian signal inference method called D3PO. The D3PO algorithm models the raw photon counts as a continuous flux and takes the Poissonian shot noise as well as all instrument effects into account. It reconstructs the logarithmic flux and its power spectrum from the data. Using this fully noise-aware method, we do not confirm previously reported frequency lines at ν=17Hz because they fall into the noise-dominated regime. However, we find two new potential candidates for oscillations at 9.2Hz (SGR 1806-20) and 7.7Hz (SGR 1900+14). If these are real and the fundamental magneto-elastic oscillations of the magnetars, current theoretical models would favour relatively weak magnetic fields B∼6x1013-3x1014G (SGR 1806-20) and a relatively low shear velocity inside the crust compared to previous findings. Description: In the files you may find the reconstructed light curve and power spectrum of SGR 1806-20 and SGR 1900+14, using two different smoothness enforcing prior. For all reconstructions we used a regular grid. Each pixel in the time domain has volume of 1/800s and its harmonic domain 1/655Hz. The interactive plot allows you to zoom into specific regions of interest. Objects: ------------------------------------------------------ RA (2000) DE Designation(s) ------------------------------------------------------ 18 08 39.32 -20 24 40.1 SGR 1806-20 = PSR J1808-2024 19 07 13. +09 19 36. SGR 1900+14 = GBS 1900+14 ------------------------------------------------------ File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 120 8 List of files files/* 0 8 Individual files
See also: J/A+A/496/765 : R light-curve of TT Ari (Kim+, 2009) J/ApJ/728/9 : XTE J1701-462 quasi-periodic oscillations (Barret+, 2011) J/MNRAS/426/1701 : High-frequency QPO in black hole binaries (Belloni+, 2012) J/MNRAS/428/1704 : XTE J1550-564 quasi-periodic oscillations (Li+, 2013) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 12 A12 --- FileName Name of the file in subdirectory files 14- 19 I6 --- N Number of points 21- 27 A7 --- Scale Value of 1 pixel (1) 29-120 A92 --- Title Title of the file
Note (1): For reconstructed light curves, the "X" value of the plot, Time in s, should be the line number divided by 800. For reconstructed power spectra, the "X" value of the plot, Freq in Hz, should be the line number divided by 655.
Acknowledgements: Daniel Pumpe, dpumpe(at), Michael Gabler, miga(at)
(End) Patricia Vannier [CDS] 27-Nov-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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