Volume 601, May 2017
|Number of page(s)||9|
|Section||Stellar structure and evolution|
|Published online||11 May 2017|
Variability of the symbiotic X-ray binary GX 1+4
Enhanced activity near periastron passage
1 Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00716 Warsaw, Poland
2 Kleinkaroo Observatory, Calitzdorp, Western Cape, South Africa
Received: 7 November 2016
Accepted: 22 February 2017
Context. GX 1+4 belongs to a rare class of X-ray binaries with red giant donors, symbiotic X-ray binaries. It has a history of complicated variability on multiple timescales in the optical light and X-rays. The nature of this variability remains poorly understood.
Aims. We aim to study variability of GX 1+4 on long timescale in X-ray and optical bands.
Methods. We took X-ray observations from the INTEGRAL Soft Gamma-Ray Imager and RXTE All Sky Monitor. Optical observations were made with the INTEGRAL Optical Monitoring Camera.
Results. The variability of GX 1+4 both in optical light and hard X-ray emission (>17 keV) is dominated by ~50–70 d quasi-periodic changes. The amplitude of this variability is highest during the periastron passage, while during the potential neutron star eclipse the system is always at minimum. This confirms the 1161 d orbital period that has had been proposed for the system based on radial velocity curve. Neither the quasi-periodic variability or the orbital period are detected in soft X-ray emission (1.3–12.2 keV), where the binary shows no apparent periodicity.
Key words: X-rays: binaries / binaries: symbiotic / stars: individual: GX 1+4
© ESO, 2017
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.