Issue |
A&A
Volume 586, February 2016
|
|
---|---|---|
Article Number | A58 | |
Number of page(s) | 7 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361/201527239 | |
Published online | 26 January 2016 |
Research Note
Multi-colour optical photometry of V404 Cygni in outburst
1
Departamento de Física, Escuela Politécnica Superior de JaénUniversidad de
Jaén,
Campus Las Lagunillas s/n, A3,
23071
Jaén,
Spain
e-mail: jmartiujaen.es; tgarcia@ujaen.es
2
Departamento de Ingeniería Mecánica y Minera, Escuela Politécnica
Superior de Jaén, Universidad de Jaén, Campus Las Lagunillas s/n, A3, 23071
Jaén,
Spain
e-mail:
peter@ujaen.es
Received: 24 August 2015
Accepted: 21 December 2015
Context. This observational paper has been prepared in the context of the large multi-wavelength effort by many observers with the aim of following up the transient flaring event of V404 Cygni that took place for several weeks in 2015 June.
Aims. Our main original aim was to contribute to the study of this transient source by acquiring broad-band photometric observations during its most active flaring phases. Nevertheless, after a detailed analysis of the data, several interesting results were obtained that encouraged a dedicated publication.
Methods. The methodology used was based on broad-band differential CCD photometry. This outburst of V404 Cygni rendered the source a very bright target easily within reach of small educational telescopes. Therefore, the 41 cm telescope available at the Astronomical Observatory of the University of Jaén was used in this work.
Results. We detected variability at different time scales, both in amplitude and colour. Individual optical flares appear every half hour on average during our 3 h long observation, although large-amplitude (~1 mag) variations are also observed to occur on intervals as short as 10 min. Also, colour variations appear to be highly correlated in a colour-colour diagram. Another remarkable finding is the detection of time lag, from about one to a fraction of a minute between light curves in different filters (VRcIc).
Conclusions. The observed behaviour is tentatively interpreted in an scenario based on the ejection of non-thermal emitting, relativistic plasmons, with their synchrotron spectra extending up to optical wavelengths. This would render some of the V404 Cygni flares very similar to those of the well-know microquasar GRS 1915+105
Key words: X-rays: binaries / stars: jets / stars: individual: V404 Cygni
© ESO, 2016
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.