Two Types of X-Ray Spectra in Cataclysmic Variables

In a 2003 paper, Mukai et al. presented the Chandra HETG spectra of 7 cataclysmic variables (CVs) then available in the public archive, and classified them into “cooling flow” and “photoionized” types. In this presentation, I will revisit this classification. It is clear that multi-temperature plasma exists in the post-shock region of accreting white dwarfs; I will discuss why the cooling flow model works well, and what its limitations are when applied to CVs. It is also clear that even the “photoionized” CVs are also powered by the same multi-temperature plasma. I will discuss how the appearance of a much harder continuum of these “photoionized” CVs is created by the complex intrinsic absorber. I will show that there is an additional soft emission in these systems that the multi-temperature plasma models cannot explain, and discuss what evidence there is for the photoionization origin of this component. Figure 1 The Cooling Flow CVs Figure 2 The Photoionized CVs

[1]  A. H. Gabriel,et al.  Interpretation of Solar Helium-Like Ion Line Intensities , 1969 .

[2]  A. C. Brinkman,et al.  XMM-Newton Reflection Grating Spectrometer Observations of Discrete Soft X-Ray Emission Features from NGC 1068 , 2002, astro-ph/0203290.

[3]  R. P. Kraft.  Binary Stars among Cataclysmic Variables. III. Ten Old Novae. , 1964 .

[4]  J. Osborne,et al.  The EF Eri Ginga data and physical models for the X-ray spectra of AM Herculis systems , 1995 .

[5]  T. Kallman,et al.  Ultraviolet Emission-line Ratios of Cataclysmic Variables* , 1996, astro-ph/9609147.

[6]  A. Szymkowiak,et al.  Einstein Observatory Solid State Detector Observations of Cooling Flows in Clusters of Galaxies , 1988 .

[7]  B. Warner.  Cataclysmic Variable Stars by Brian Warner , 1995 .

[8]  Ko Aizu,et al.  X-Ray Emission Region of a White Dwarf with Accretion , 1973 .

[9]  Steven M. Kahn,et al.  The Chandra High-Energy Transmission Grating Observation of an X-Ray Ionization Cone in Markarian 3 , 2000 .

[10]  Delphine Porquet,et al.  X-ray photoionized plasma diagnostics with Helium-like ions. Application to Warm Absorber-Emitter in Active Galactic Nuclei , 2000 .

[11]  Gavin Ramsay,et al.  White dwarf masses in magnetic cataclysmic variables: multi-temperature fits to Ginga data , 1998 .

[12]  Vol Xiii,et al.  Astronomical Society of the Pacific , 1937, Nature.

[13]  S. Kahn,et al.  High resolution X-ray spectroscopy of $\zeta$ Puppis with the XMM-Newton reflection grating spectrometer , 2000, astro-ph/0011026.

[14]  D. Liedahl.  The X-Ray Spectral Properties of Photoionized Plasmas and Transient Plasmas , 1999 .

[15]  J. Jernigan,et al.  High-Resolution X-Ray Spectroscopic Constraints on Cooling-Flow Models for Clusters of Galaxies , 2002, astro-ph/0210662.

[16]  M. Sako,et al.  The soft X-ray spectrum from NGC 1068 observed with LETGS on Chandra , 2002, astro-ph/0211403.

[17]  J. Patterson,et al.  X-ray emission from cataclysmic variables with accretion disks. I - Hard X-rays. II - EUV/soft X-ray radiation , 1985 .

[18]  J. Jernigan,et al.  X-ray imaging spectroscopy of Abell 1835 , 2000, astro-ph/0010658.

[19]  Knox S. Long,et al.  Chandra Spectra of the Prototype Dwarf Nova U Geminorum at Quiescence , 2002 .

[20]  K. Beuermann.  The Physics of Cataclysmic Variables and Related Objects , 2002 .

[21]  A. Fabian,et al.  Subsonic accretion of cooling gas in clusters of galaxies , 1977 .

[22]  Gavin Ramsay,et al.  Determining the mass of the accreting white dwarf in magnetic cataclysmic variables using RXTE data , 1999, astro-ph/9912420.

[23]  E. Valentijn.  Cooling flows in clusters and galaxies , 1988 .

[24]  J. Paradijs,et al.  X-Ray Spectroscopy in Astrophysics , 1999 .