Multiwavelength monitoring of a very active dwarf nova AX J1549.8-5416 with an unusually high duty cycle
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Archivos
Fecha
2017-08
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
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Título del volumen
Editor
Oxford University Press
Nombre de Curso
Licencia CC
CC BY 4.0 DEED
Atribución 4.0 Internacional
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
We present the results of our analysis of new optical, ultraviolet (UV) and X-ray observations of a highly variable source - AX J1549.8-5416. Both the detection of several fast rise, exponential decay outbursts in the optical light curve and the lack of He II emission lines in the optical spectra suggest AX J1549.8-5416 is a cataclysmic variable of the dwarf nova (DN) type. The multiwavelength analysis of three mini-outbursts and one normal outburst represent one of the most complete multiwavelength studies of a DN and help to refine the relationship between the X-ray, UV and optical emission in this system. We find that the UV emission is delayed with respect to the optical by 1.0 5.4 d during the rising phase of the outburst. The Xray emission is suppressed during the peak of the optical outburst and recovers during the end of the outburst. From our analysis of archival Swift, Chandra and XMM Newton observations of AX J1549.8-5416, we estimate this DN has a high duty cycle (∼50 per cent), suggesting a quiescent X-ray luminosity larger than 1032 erg s-1. We also find the X-ray and UV flux are roughly anticorrelated. Furthermore, we find that, at low X-ray fluxes, the X-ray spectrum is well described by a single temperature thermal plasma model, while at high X-ray fluxes, an isobaric cooling flow model also works. We find that the maximum temperature of the plasma in quiescence is significantly higher than that in outburst. © 2017 The Authors.
Notas
Indexación: Scopus
Palabras clave
Stars: dwarf novae, Stars: individual: AX J1549.8-5416, X-rays: binaries
Citación
Monthly Notices of the Royal Astronomical Society Volume 469, Issue 4, Pages 4236 - 42481 August 2017
DOI
10.1093/mnras/stx1106