Swift observations of GW Lib: a unique insight into a rare outburst

Abstract

The second known outburst of the WZ Sge type dwarf nova GW Lib was observed in April 2007. We have obtained unique multiwavelength data of this outburst which lasted ~ 26 days. AAVSO observers recorded the outburst in the optical, which was also monitored by WASP, with a peak V magnitude of ~ 8. The outburst was followed in the UV and X-ray wavelengths by the Swift UVOT and XRT telescopes. The X-ray flux at optical maximum was found to be three orders of magnitude above the pre-outburst quiescent level, whereas X-rays are normally suppressed during dwarf nova outbursts. A distinct supersoft X-ray component was also detected at optical maximum, which probably arises from an optically-thick boundary layer. Follow-up Swift observations taken one and two years after the outburst show that the post-outburst quiescent X-ray flux remains an order of magnitude higher than the pre-outburst flux. The long interoutburst timescale of GW Lib with no observed normal outbursts support the idea that the inner disc in GW Lib is evacuated or the disc viscosity is very low.

14 pages, 7 figures, accepted for publication in MNRAS

References in corpus (3)

• ULTRACAM observations of two accreting white dwarf pulsators
• Magnetically moderated outbursts of WZ Sagittae
• XMM-Newton Observations of the Cataclysmic Variable GW Lib

Cited by in corpus (19)

• X-ray Emissions from Accreting White Dwarfs: a Review
• Deriving an X-ray luminosity function of dwarf novae based on parallax measurements
• The Swift-UVOT ultraviolet and visible grism calibration
• The Fall and the Rise of X-rays from Dwarf Novae in Outburst: RXTE Observations of VW Hydri and WW Ceti
• X-ray observations of SU UMa throughout six outbursts
• Accretion Flows in Nonmagnetic White Dwarf Binaries as Observed in X-rays
• GALEX and Optical Observations of GW Librae During the Long Decline from Superoutburst
• Multi-wavelength observations of the helium dwarf nova KL Dra through its outburst cycle
• Paving the way to simultaneous multi-wavelength astronomy
• XMM-Newton and Swift observations of WZ Sge: spectral and timing analysis
• Superhumps linked to X-ray emission. The superoutbursts of SSS J122221.7-311525 and GW Lib
• The Luminosity Phase Space of Galactic and Extragalactic X-ray Transients Out to Intermediate Redshifts
• The post-outburst pulsations of the accreting white dwarf in the cataclysmic variable GW Librae
• The Fast Evolving, Tremendous and Blue Superoutburst in ASASSN-21au Reveals a Dichotomy in the Outbursts of Long-period AM CVns
• Broad Observational Perspectives Achieved by the Accreting White Dwarf Sciences in the XMM-Newton and Chandra Eras
• Synergies between Exoplanet Surveys and Variable Star Research
• XMM-Newton observation of V1504 Cyg as a probe for the existence of an evaporated corona
• X-ray emission mechanisms in accreting white dwarfs
• Time Domain Astronomy with the THESEUS Satellite