Wheatley, P. J., Mauche, Christopher W. and Mattei, Janet A. (2003) The X-ray and extreme-ultraviolet flux evolution of SS Cygni throughout outburst. Monthly Notices of the Royal Astronomical Society, 345 (1). pp. 49-61. doi:10.1046/j.1365-8711.2003.06936.x ISSN 0035-8711.

PDF WRAP_49.full.pdf - Published Version - Requires a PDF viewer. Download (1152Kb)

Request Changes to record.

Abstract

We present the most complete multiwavelength coverage of any dwarf nova outburst: simultaneous optical, Extreme Ultraviolet Explorer and Rossi X-ray Timing Explorer observations of SS Cygni throughout a narrow asymmetric outburst. Our data show that the high-energy outburst begins in the X-ray waveband 0.9–1.4 d after the beginning of the optical rise and 0.6 d before the extreme-ultraviolet rise. The X-ray flux drops suddenly, immediately before the extreme-ultraviolet flux rise, supporting the view that both components arise in the boundary layer between the accretion disc and white dwarf surface. The early rise of the X-ray flux shows that the propagation time of the outburst heating wave may have been previously overestimated.

The transitions between X-ray and extreme-ultraviolet dominated emission are accompanied by intense variability in the X-ray flux, with time-scales of minutes. As detailed by Mauche & Robinson, dwarf nova oscillations are detected throughout the extreme-ultraviolet outburst, but we find they are absent from the X-ray light curve.

X-ray and extreme-ultraviolet luminosities imply accretion rates of 3 × 1015 g s−1 in quiescence, 1 × 1016 g s−1 when the boundary layer becomes optically thick, and ∼1018 g s−1 at the peak of the outburst. The quiescent accretion rate is two and a half orders of magnitude higher than predicted by the standard disc instability model, and we suggest this may be because the inner accretion disc in SS Cyg is in a permanent outburst state.

Item Type:	Journal Article
Subjects:	Q Science > QB Astronomy
Divisions:	Faculty of Science, Engineering and Medicine > Science > Physics
Library of Congress Subject Headings (LCSH):	Accretion (Astrophysics), Cataclysmic variable stars, Dwarf novae
Journal or Publication Title:	Monthly Notices of the Royal Astronomical Society
Publisher:	Oxford University Press
ISSN:	0035-8711
Official Date:	2003
Dates:	Date Event 2003 Published 13 June 2003 Accepted
Volume:	345
Number:	1
Page Range:	pp. 49-61
DOI:	10.1046/j.1365-8711.2003.06936.x
Status:	Peer Reviewed
Publication Status:	Published
Date of first compliant deposit:	6 January 2017
Date of first compliant Open Access:	11 January 2017
Funder:	University of Leicester, Lawrence Berkeley laboratory, United States. National Aeronautics and Space Administration (NASA)
Grant number:	Contract No. W-7405-Eng-48 (Lawrence Berkeley laboratory), Grant NAG5-7027 (NASA)
Open Access Version:	ArXiv

Request changes or add full text files to a record

Repository staff actions (login required)

View Item

Downloads