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Populations of Galactic X-ray (compact) sources visible to Spectrum-RG

Populations of Galactic X-ray (compact) sources visible to Spectrum-RG. Revnivtsev M., Space Research Institute; Moscow, Russia. Discrete X-ray emitters in the Galaxy. Binaries with relativistic objects – X-ray binaries. High mass and low mass companions

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Populations of Galactic X-ray (compact) sources visible to Spectrum-RG

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  1. Populations of Galactic X-ray (compact) sources visible to Spectrum-RG Revnivtsev M., Space Research Institute; Moscow, Russia

  2. Discrete X-ray emitters in the Galaxy • Binaries with relativistic objects – X-ray binaries. High mass and low mass companions • Single relativistic objects: cooling neutron stars, rotation powered pulsars.. • Binaries with accreting white dwarfs • Stars with active coronae, binary stars (the most numerous sources)

  3. Expected spatial distribution of CVs, LMXBs… High interstellar absorption

  4. It is very hard to study Galactic sources Extragalactic sky Galactic ISM

  5. You should see through walls But you often find something interesting and useful

  6. ROSAT 1-2 keV sens.limit 10-12 erg/s/cm2 Severe absorption in the G.Plane

  7. INTEGRAL 17-60 keV sens. limit ~10-11 erg/sec/cm2 Harder X-rays are extremely valuable for Galactic surveys – ART-XC

  8. Why population studies? 1. Search for sources to be studied individually 2. Properties of populations can tell us about their formation … about interactions in binary systems (MSW, GW, outflows?) 3 …. about average properties of compact objects (e.g. magnetic field, rotation rates at birth etc) 4 … about long term evolution of objects (e.g. accumulation/erosion of WD masses etc)

  9. Bulge of the Milky Way M31 Only in our Galaxy we can study companions of X-ray binaries –> clues to physical mechanisms of their evolution

  10. LMXB ? LEdd for NS binary Voss, Gilfanov 2006 What is the origin of this break?

  11. LogLx~37 -- boundary between main sequence and giants companions? MS WD Revnivtsev et al. 2011

  12. Kuranov et al.. (preliminary)

  13. LMXB age evolution? L2dN/dL Lx

  14. Propeller effect Illarionov, Sunyaev 1975 35 G Campana et al. 1998

  15. propeller? This is the reason of absence of faint LMXBs? Task for Spectrum-XG

  16. Simulated LMXBs in the Galactic bulge (sensitivity 10-13 erg/s/cm^2, no absorption)

  17. High mass X-ray binaries INTEGRAL view of the Gal.Plane

  18. HMXB “hole” in the Galactic disk? Lutovinov et al. (2012, in preparation)

  19. Galactic HMXBs Parameter space, reachable for Spectrum-XG In total 100-200 sources! Lx<1034-34.5 erg/sec

  20. Study of HMXB population is beyond reach of telescopes like CHANDRA, XMM or NuSTAR due to their limited fields of view ~2-3/sq.deg!! figure of R.Krivonos

  21. Cataclysmic variables

  22. All sky survey – spatial distribution of cataclysmic variables Post bounce (older?) systems wider spreaded? Now only ~20 objects SRG expects >100000 Revnivtsev et al. 2008

  23. Numerical modeling of cataclysmic variables Old and the most numerous Howell et al. 2001

  24. Low Mdot CVs accumulate mass in a long run? No WD erosion? Zero age WD mass We need bias-free surveys! Littlefair et al. 2008

  25. Counting CVs in the Galaxy is a complicated problem: biases Typical CV discovery: 1)Dwarf nova outbursts, 2)classical nova 3)UV color excess ………… One of the latest results:usage of wide uniform surveys of the sky - SDSS Szkody et al. 2003

  26. Optical selection of CVs Selection: WD contribution in blue part of spectrum

  27. Even this simple attempt to have less biased search revealed a completely different CV population Before SDSS SDSS sample Gansicke et al. 2009

  28. Colors and brightnesses of WD of different masses T Bergeron et al. 1995 Bias toward lower masses WDs?

  29. CVs in X-rays X-ray surveys Depends on mass of WD and B-field Spectrum-XG area

  30. Van Paradijs & McClintock 1994 O’Brien et al. 2002 Mescheryakov et al. 2011 Problems of finding low-Lx LMXBS (even worse for qLMXB Revnivtsev et al. 2011 MK as faint as >4-5!

  31. SAX J1747 • Hard targets • hunt for low Lx • LMXBs Extremely faint sources in crowded regions IGR J17254

  32. LMXB HMXB CV

  33. Spectra of CVs and Active Binaries ART-XC energy range eROSITA energy range

  34. For populations studies – future X-ray surveys Spectrum-XG (eROSITA+ART) Stars - millions CVs – 100 000 -500 000

  35. Summary: • Studies of populations provide us handles on: • formation of binaries • mechanisms of their long term evolution • On averaged properties of populations (compact objects magnetic fields, spatial distribution/kinematic age etc… Vital issue: algorithms of identification of Galactic sources among huge number of sources expected in Spectrum-XG surveys

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