English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present {\it Chandra} HETG observations of SS Cygni in quiescence andoutburst. The spectra are characterized by He-like and H-like Ka emission linesfrom O to Fe, as well as L-shell emission lines from Fe. In quiescence, thespectra are dominated by the H-like Ka lines, whereas in outburst the He-likelines are as intense as the H-like lines. In outburst, the H-like Ka lines fromO to Si are broad, with widths of 4--14 eV in Gaussian $\sigma$ (1800--2300${\rm km s^{-1}}$). The large line widths, together with line profiles, indicatethat the line-emitting plasma is associated with the Keplerian disk and stillretains the azimuthal bulk motion. In quiescence, the emission lines arenarrower, with a Gaussian $\sigma$ of 1--3 eV (420--620$ {\rm km s^{-1}}$). Aslightly larger velocity for lighter elements suggests that the lines inquiescence are emitted from an ionizing plasma at the entrance of the boundarylayer, where the bulk motion of the optically thick accretion disk is convertedinto heat due to friction. Using the line intensity ratio of He-like and H-likeKa lines for each element, we have also investigated the temperaturedistribution in the boundary layer both in quiescence and outburst. Thedistribution of SS Cyg is found to be consistent with other dwarf novaeinvestigated systematically with {\it ASCA} data.

Chandra HETG line spectroscopy of the Non-magnetic Cataclysmic Variable SS Cyg