X-ray and optical observations of A0535+26
We present recent contemporaneous X-ray and optical observations of the Be/X-ray binary system A0535+26 with the Fermi/Gamma-ray Burst Monitor (GBM) and several ground-based observatories. These new observations are put into the context of the rich historical data (since ∼1978) and discussed in term...
| Autores: | , , , , , , , , , , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2012 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/414914 |
| Acceso en línea: | http://hdl.handle.net/10261/414914 |
| Access Level: | acceso abierto |
| Palabra clave: | Accretion, accretion disks Pulsars: individual (A 0535+26) Stars: emission-line, Be Stars: neutron X-rays: binaries |
| Sumario: | We present recent contemporaneous X-ray and optical observations of the Be/X-ray binary system A0535+26 with the Fermi/Gamma-ray Burst Monitor (GBM) and several ground-based observatories. These new observations are put into the context of the rich historical data (since ∼1978) and discussed in terms of the neutron-star-Be-disk interaction. The Be circumstellar disk was exceptionally large just before the 2009 December giant outburst, which may explain the origin of the unusual recent X-ray activity of this source. We found a peculiar evolution of the pulse profile during this giant outburst, with the two main components evolving in opposite ways with energy. A hard 30-70mHz X-ray quasi-periodic oscillation was detected with GBM during this 2009 December giant outburst. It becomes stronger with increasing energy and disappears at energies below 25keV. In the long term a strong optical/X-ray correlation was found for this system, however in the medium term the Hα equivalent width and the V-band brightness showed an anti-correlation after ∼2002 August. Each giant X-ray outburst occurred during a decline phase of the optical brightness, while the Hα showed a strong emission. In late 2010 and before the 2011 February outburst, rapid V/R variations are observed in the strength of the two peaks of the Hα line. These had a period of ∼25days and we suggest the presence of a global one-armed oscillation to explain this scenario. A general pattern might be inferred, where the disk becomes weaker and shows V/R variability beginning ∼6 months following a giant outburst. © 2012. The American Astronomical Society. All rights reserved. |
|---|