* Astronomy

Blobrana · L

RE: XTE J1859+226

Blobrana · L

ING Joins Efforts with GTC to Discover a Galactic Black Hole

XTE J1859+226 is a transient X-ray binary discovered in 1999 by the X-ray satellite RXTE. X-ray binaries are formed from the pairing of a compact object, either a neutron star or a black hole, and a 'normal' star. The compact object pulls out material from the star which eventually falls onto an accretion disc surrounding the compact object. This type of binary system stays in quiescence for most of its life; however, from time-to-time the system can show an outburst at all wavelengths which can subsequently be detected by X-ray satellites.
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Blobrana · L

Title: Evidence for a black hole in the X-ray transient XTE J1859+226
Authors: J. M. Corral-Santana, J. Casares, T. Shahbaz, C. Zurita, I. G. Martínez-Pais, P. Rodríguez-Gil

We present the results of time-resolved optical photometry and spectroscopy of the X-ray transient XTE J1859+226 (V406 Vul). Photometric observations taken during 2000 and 2008 reveals the presence of the secondary star's ellipsoidal modulation. Further photometry obtained in 2010 shows the system ~1 mag brighter than its quiescence level and the ellipsoidal modulation diluted by strong flaring activity. Spectroscopic data obtained with the 10.4-m GTC in 2010 reveals radial velocity variations of ~500 km/s over 3 h. A simultaneous fit to the photometry and spectroscopy using sinusoids to represent the secondary star's ellipsoidal and radial velocity variations, yields an orbital period of 6.58±0.05 h and a secondary star's radial velocity semi-amplitude of K_2= 541±70 km/s. The implied mass function is f(M)=4.5±0.6 Msun, significantly lower than previously reported but consistent with the presence of a black hole in XTE J1859+226. The lack of eclipses sets an upper limit to the inclination of 70 degrees which yields a lower limit to the black hole mass of 5.42 Msun.

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Blobrana · L

Descubren un agujero negro de más de cinco veces la masa del Sol

El Gran Telescopio Canarias obtiene los primeros espectros sobre el sistema binario XTE J1859+226 que confirman la presencia de un agujero negro
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Blobrana · L

Astrónomos españoles descubren un agujero negro de más de 5 veces la masa del Sol

Investigadores del Instituto de Astrofísica de Canarias (IAC) han descubierto un agujero negro de más de 5,4 veces la masa del Sol en el sistema binario de rayos X XTE J1859+226, según han detectado en observaciones realizadas desde el Gran Telescopio Canarias. Según informa el IAC en un comunicado, el Gran Telescopio Canarias ha logrado obtener los primeros espectros que se publican de este sistema binario y que han sido determinantes en el hallazgo.
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