Follow Us| SS Cyg | ||||||||||||||||||
| The spectrum consists of eight individual FUSE exposures (orbits) combined together. The system was in a relatively low state at the time of the observations. The FUSE spectrum is characterized by a relatively low flux with broad emission lines (Hydrogen Lyman series, C iii, N iii and O vi doublet). The spectrum has a ``forest' of ISM lines: molecular hydrogen (marked in the top of each panel in the figure), atomic hydrogen (marked below each panel), oxygen (O i) and few metal lines (marked in the lower part of the panels). The spectrum has been dereddened assuming E(B-V)=0.04. The main spectral features that belong to the source are the braod emission lines from C iii (977 and 1175) and the oxygen doublet. The absorption lines that are usually seen in WD photosphere (e.g. from S and Si) are not detected at all and the continuum appear to be rather featureless. A composite WD+Disk model has been fit to this spectrum. The disk contributes only 12% of the flux while the WD contributes the remaining 88% of the flux. The increase in flux in the shorter wavelengths of FUSE could be due to broad and strong emission lines of N iv, S vi, C iii and the higher order of the Hydrogen Lyman series merging together to form a continuum, but it could also be due to the tail of a hotter source. The distance obtained from this fit is 173pc, in excellent agreement with its trigonometric parallax distance. The complete analysis is given in Sion et al. (2010). | |||||||||||||||||
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FUSE Data
Synthetic Spectrum
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These data and models were published in the paper: Sion, E.M., Godon, P., Myszka, J., Blair, W.P., 2010, ApJ, 716, 157 | ||||||||||||||||||||||||||||||||||||
Notes on figures:The flux (vertical axis) is given in ergs/sec/cm2/A and the wavelength (horizontal axis) is given in Angstroem. For clarity the spectrum is shown on 3 panels: the upper panel from about 900 to 1000A, the middle panel from about 1000A to 1100A, and the lower panel from about 1100A to 1200A. Air glow emission is anoted above each panel with a "+" sign inside a circle. Strong emission lines reaching the upper part of the frame in each pael is marked just above the panel. The Hydrogen series is marked below the x-axis in the upper and middle panel and the hydrogen cut-off limit is clearly marked around 915A with an increasing density of tick marks. The He I (1168A) is marked below the lower panel. Oxygen I lines are shown with an arrow "OI -->" if many (ISM) OI lines are present, they are just annotated with verical tick marks in the lower portion of each panel. ISM molecular hydrogen lines are either individually annotated vertically (e.g. L10R1) or just marked with an arrow "MH -->" and vertical tick marks (usually in the upper part of each panel). Features resulting from fixed pattern noise introduced by FUSE detect ors are indicated with "FPN;.When a model is shown, the portions of the observed spectrum that have been masked before the spectral fit are in blue, while the rest of the observed spectrum is in red. The model fit is shown the solide line in black (or possibly white). If the model is a composite made of a disk model and a white dwarf model, then these are shown with the dashed- and dotted lines (respectively). Some models include the effect of quasi-molecular HI absorption features, these are labelled "Q-mol" in the spectrum. |
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