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SCIENTIA SINICA Physica, Mechanica & Astronomica, Volume 48, Issue 3: 039511(2018) https://doi.org/10.1360/SSPMA2017-00247

Einstein Probe: Application on the observation ofcataclysmic variables

XiaoJie XU1,2,*
More info
  • ReceivedSep 15, 2017
  • AcceptedOct 9, 2017
  • PublishedJan 9, 2018
PACS numbers

Abstract

Cataclysmic variables (CVs) are binaries where a white dwarf star accretes matter from its companion. CVs are important X-ray emitters in the Milky Way. Our knowledge on CVs is limited by the incompleteness of CV samples, especially those with low X-ray luminosities (Lx<1.0×1032 erg s−1). Einstein Probe (EP) is a powerful instrument to search for nearby CVs. In one year of operation, EP can provide a complete sample of CVs above 5.0×1030 erg s−1 within 300 parsec, and the total estimated number of CVs could reach 1000. Based on this sample, the X-ray luminosity function of nearby CVs could be built, which will further be used to investigate key astrophysical questions like the diffuse emission of galaxies and the progenitors of type Ia supernovae.


Funded by

国家自然科学基金(编号:)

中国科学院战略性先导科技专项(编号:)


References

[1] Pretorius M L, Knigge C. The space density and X-ray luminosity function of non-magnetic cataclysmic variables. Mon Not R Astron Soc, 2012, 419: 1442-1454 CrossRef ADS arXiv Google Scholar

[2] Wheatley P J, Mauche C W, Mattei J A. The X-ray and extreme-ultraviolet flux evolution of SS Cygni throughout outburst. Mon Not R Astron Soc, 2003, 345: 49-61 CrossRef ADS Google Scholar

[3] Sazonov S, Revnivtsev M, Gilfanov M, et al. X-ray luminosity function of faint point sources in the Milky Way. Astron Astrophys, 2006, 450: 117-128 CrossRef ADS Google Scholar

[4] Byckling K, Mukai K, Thorstensen J R, et al. Deriving an X-ray luminosity function of dwarf novae based on parallax measurements. Mon Not R Astron Soc, 2010, 408: 2298-2311 CrossRef ADS arXiv Google Scholar

[5] Reis R C, Wheatley P J, Gänsicke B T, et al. X-ray luminosities of optically selected cataclysmic variables and application to the Galactic ridge X-ray emission. Mon Not R Astron Soc, 2013, 430: 1994-2001 CrossRef ADS arXiv Google Scholar

[6] Revnivtsev M, Sazonov S, Churazov E, et al. Discrete sources as the origin of the Galactic X-ray ridge emission. Nature, 2009, 458: 1142-1144 CrossRef PubMed ADS arXiv Google Scholar

[7] Warwick R S, Saxton R D, Read A M. The XMM-Newton slew survey in the 2–10 keV band. Astron Astrophys, 2012, 548: A99 CrossRef ADS arXiv Google Scholar

[8] Warwick R S, Byckling K, Pérez-Ramírez D. The Galactic plane at faint X-ray fluxes–II. Stacked X-ray spectra of a sample of serendipitous XMM-Newton sources. Mon Not R Astron Soc, 2014, 438: 2967-2979 CrossRef ADS arXiv Google Scholar

[9] Warwick R S. Low-luminosity X-ray sources and the Galactic ridge X-ray emission. Mon Not R Astron Soc, 2014, 445: 66-80 CrossRef ADS arXiv Google Scholar

[10] Hong J S. Dominance of magnetic cataclysmic variables in the resolved Galactic ridge X-ray emission of the limiting window. Mon Not R Astron Soc, 2012, 427: 1633-1650 CrossRef ADS arXiv Google Scholar

[11] Pretorius M L, Knigge C, Schwope A D. The space density of magnetic cataclysmic variables. Mon Not R Astron Soc, 2013, 432: 570-583 CrossRef ADS arXiv Google Scholar

[12] van den Berg M, Hong J S, Grindlay J E. ChaMPlane deep galactic bulge survey. I. faint accretion-driven binaries in the limiting window. Astrophys J, 2009, 700: 1702-1715 CrossRef ADS arXiv Google Scholar

[13] Hong J S, van den Berg M, Grindlay J E, et al. Discovery of a significant magnetic cataclysmic variable population in the limiting window. Astrophys J, 2012, 746: 165 CrossRef ADS arXiv Google Scholar

[14] Revnivtsev M, Sazonov S, Forman W, et al. Luminosity function of faint Galactic sources in the Chandra bulge field. Mon Not R Astron Soc, 2011, 414: 495-499 CrossRef ADS arXiv Google Scholar

[15] Swank J H, Boldt E A, Holt S S, et al. Hard X-rays from U geminorum. Astrophys J, 1978, 226: L133-L136 CrossRef ADS Google Scholar

[16] Baskill D S, Wheatley P J, Osborne J P. The complete set of ASCA X-ray observations of non-magnetic cataclysmic variables. Mon Not R Astron Soc, 2005, 357: 626-644 CrossRef ADS Google Scholar

[17] Verbunt F, Bunk W, Ritter H, et al. Cataclysmic variables in the ROSAT PSPC all sky survey. Astron Astrophys, 1997, 327: 602–613. Google Scholar

  • Figure 1

    (Color online) The X-ray luminosity distribution of sampled nearby cataclysmic variables (CVs) by Sazonov et al. [3].

  • Figure 2

    (Color online) The luminosity function of point sources detected in the “Limiting Window” in the Galactic bulge [14]. The red region represents the luminosity function; for comparison, the luminosity function of nearby CVs and Abs is also presented as the blue region [3].

  • Figure 3

    (Color online) CVs detected in the ROSAT survey [10]. X axis: optical magnitude, Y axis: X-ray count rate. The red dashed line represents EP detection limit after 1 ks exposure.

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