Open AccessFUSE and HST ultraviolet observations of the disc wind of RW Sextantis
Author(s) -
Prinja R. K.,
Long K. S.,
Froning C. S.,
Knigge C.,
Witherick D. K.,
Clark J. S.,
Ringwald F. A.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06307.x
Subject(s) - physics , astrophysics , space telescope imaging spectrograph , spectral line , astronomy , outflow , radial velocity , ionization , stars , hubble space telescope , meteorology , quantum mechanics , ion
We present Far Ultraviolet Spectroscopic Explorer ( FUSE ) satellite time‐series data of the low‐inclination, nova‐like cataclysmic variable RW Sex. The data span the wavelength range between ∼905 and 1188 Å, which contains the resonance lines of C iii , N iii , S iv , P v , S vi and O vi . All these spectral lines are present in the form of blueshifted absorption components, with no evidence for the lines redward of rest velocity; the FUSE data probe the fast disc‐wind of RW Sex. The time‐variable nature of these features is established. Substantial line profile variability is observed, confined between ∼−1000 and 0 km s −1 , and modulated on the orbital period of the system (∼0.245 d) . The fundamental characteristics of the temporal behaviour are very similar between the low and high ionization lines. The wind‐dominated lines exhibit a cyclic increase in absorption optical depth which is accompanied by a shift in the maximum absorption velocity from ∼−1000 km s −1 to near zero velocity. We argue that the empirical evidence from the FUSE analysis supports an interpretation of blueshifted absorptive changes as opposed to the action of a variable (in velocity) blueshifted (perhaps disc‐formed) emission component. This conclusion is further bolstered by an analysis of archival Hubble Space Telescope ( HST ) Goddard High Resolution Spectrograph (GHRS) data of RW Sex. We discuss a phenomenological picture of the ultraviolet (UV) line profile variability where the symmetry of a confined bipolar wind in RW Sex is broken by assuming that the outflow is oblique, perhaps because it is seated on a warped or tilted disc. The temporal UV absorption properties of non‐eclipsing nova‐like systems are compared.