Abstract

Context. WZ Sagittae is the prototype object of a subclass of dwarf novae with rare and long (super)outbursts, in which a white dwarf primary accretes matter from a low mass companion. High-energy observations offer the possibility of a better understanding of the disk-accretion mechanism in WZ Sge-like binaries. Aims: We used archival XMM-Newton and Swift data to characterize the X-ray spectral and temporal properties of WZ Sge in quiescence. Methods: We performed a detailed timing analysis of the simultaneous X-ray and UV light curves obtained with the EPIC and OM instruments on board XMM-Newton in 2003. We employed several techniques in this study, including a correlation study between the two curves. We also performed an X-ray spectral analysis using the EPIC data and Swift/XRT data obtained in 2011. Results: We find that the X-ray intensity is clearly modulated at a period of ≃28.96 s, confirming previously published preliminary results. We find that the X-ray spectral shape of WZ Sge remains practically unchanged between the XMM-Newton and Swift observations. However, after correcting for interstellar absorption, the intrinsic luminosity is estimated to be LXUna = (2.65 ± 0.06) × 1030 erg s-1 and LXUna = (1.57 ± 0.03) × 1030 erg s-1 in 2003 and 2011, respectively. During the Swift/XRT observation, the observed flux is a factor ≃2 lower than that observed by XMM-Newton but is similar to the quiescent levels that are observed various times before the 2001 outburst.

Autore Pugliese

• De Paolis Francesco , Ingrosso Gabriele , Nucita Achille

Tutti gli autori

• A. A. Nucita , E. Kuulkers , F. De Paolis , K. Mukai , G. Ingrosso , B. M. T. Maiolo

Titolo volume/Rivista

ASTRONOMY & ASTROPHYSICS

Anno di pubblicazione

2014

ISSN

0004-6361

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

2

Ultimo Aggiornamento Citazioni

28/04/2018

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile