2003/01/28 by K. Mukai, A. Kinkhabwala, Ali Kinkhabwala +3 · 2 citations
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/374583
published as Astrophys.J. 586 (2003) L77-L80 · 12 pages including 2 color figures, accepted for publication in Astrophysical Journal Letters
arxiv created 2003/01/28 · openalex publication_date 2003/03/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We present Chandra high-energy transmission grating spectra of seven cataclysmic variables. We find that they divide unambiguously into two distinct types. Spectra of the first type are remarkably well fitted by a simple cooling flow model, which assumes only steady-state isobaric radiative cooling. The maximum temperature, kT max , and the normalization, which provides a highly precise measurement of the accretion rate, are the only free parameters of this model. Spectra of the second type are grossly inconsistent with a cooling flow model. They instead exhibit a hard continuum and show strong H-like and He-like ion emission but little Fe L-shell emission, which is consistent with expectations for line emission from a photoionized plasma. Using a simple photoionization model, we argue that the observed line emission for these sources can be driven entirely by the hard continuum. The physical significance of these two distinct types of X-ray spectra is also explored.