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The 7-year view of the accreting X-ray binaries with INTEGRAL R.Krivonos, M.Revnivtsev, S.Tsygankov, E.Churazov, R.Sunyaev MPA Garching, Germany; IKI, Moscow, Russia
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Galactic Center region, 20 Ms, 17-60 keV Limiting flux ~0.26 mCrab 3.7e-12 erg/s/cm 2 Luminosity 4e+34 erg/s at the distance of GC The Milky Way is a unique galaxy where we can detect X- ray objects with the lowest possible luminosities.
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Stellar density field Galactic Center region, 20 Ms, 17-60 keV
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Low-Massive X-ray Binaries in Bulge Revnivtsev et al., 2008
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Low-Massive X-ray Binaries in Bulge d log N / d log L = -0.96 +/- 0.20 at log(L) < 37 Break in dM/dT distribution? Change in Lx – dM/dT relation? Recent: the break is due to different classes of companion stars: Gilfanov 2004 Revnivtsev et al., 2010
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Galactic ridge X-ray emission with INTEGRAL It is shown that the Ridge is due to point sources at energies <10 keV (Revnivtsev et al. 2006, 2007, 2008, 2009)` What is in hard X-rays? Cataclysmic Variables: first approach
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INTEGRAL view of the GRXE NIR contours Krivonos et al. 2006, 2009
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Galactic ridge emission in hard X-rays consists of emission of millions of CVs! Shape of cutoff average mass of WDs ~0.5-0.6 M sun INTEGRAL RXTE
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The dominant class of INTEGRAL CV is intermediate polars Revnivtsev et al., 2008 INTEGRAL provides one of the largest unbiased sample of luminous intermediate polars existing today (37 in the 7-year survey) The survey is serendipitous with respect to CVs Cataclysmic Variables INTEGRAL Cataclysmic Variables: second approach
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Cataclysmic Variables Scale height of Galactic disk population is 130 (+90-50) kpc
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Luminosity function of hard X-ray emitting CVs only from INTEGRAL all sky survey! Revnivtsev et al. 2008 Cumulative emissivity of CVs in 17-60 keV Ridge value in 17-60 keV INTEGRAL points RXTE points
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Revnivtsev et al. 2008
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Density of HMXBs In the Galactic plane INTEGRAL survey Simple toy model Lutovinov et al. 2005, 2007
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The position of spiral arms (ignored) Shtykovskiy & Gilfanov 2007
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Method: Integrate the galactic disk model with a given luminosity function, given survey sensitivity map, and measure the probability to have the observed distribution of sources.
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-- measured -- not ID -- predicted High-Massive X-ray Binaries distribution over the Galactic longitude Crux Carina Norma Cyg Sgr
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Disk without hole
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r_disk = 2.2 (+0.6-0.4) kpc Disk size
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dN/dL ~L Probing the LF (single) slope over Log(L) 33-38 -Gamma Gamma = 1.3 (+0.3-0.2) Voss & Ajello 2010
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Maximum Likelihood HMXB Luminosity Function delta Likelihood < 1.0 Log
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Unrealistic LF shape: Overprediction at low luminosities Log
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Unrealistic LF shape: Underprediction at low luminosities Like “Propeller effect” Log
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dN/dL~L^1.5 Absolutely unrealistic LF shape: Log
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The perfect sky imaging with IBIS/ISGRI is possible: IKI/RSDC http://hea.iki.rssi.ru/integral MPA http://www.mpa-garching.mpg.de/integral Concluding remarks (1) 7-year Galactic Bulge Map Galactic Plane Survey Galactic Bulge Monitoring Catalog of sources with spectra and lightcurves INTEGRAL/IBIS 7-year All-Sky Hard X-Ray Survey. Part I: Image Reconstruction A&A (arXiv:1006.2463) INTEGRAL/IBIS 7-year All-Sky Hard X-Ray Survey. Part II: Catalog of Sources A&A (arXiv:1006.4437)
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Flat end of luminosity function at Log (L) < 37 The cumulative angular distribution in the Galactic center region traces the cumulative number of stars (bulge and nuclear stellar disk components) Concluding remarks (2) LMXB in Bulge => Break in dM/dT distribution? => Change in Lx – dM/dT relation? => Different classes of companions
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The scale height of the Galactic disk 130 (+90-50) kpc Luminosity Function Luminosity density is consistent with that measured from unresolved emission (“Rigde”) Concluding remarks (3) Cataclysmic Variables
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Spatial distribution of HMXB allows one to constrain lower and upper limits for luminosity function regardless distance information Probe of flattening at Log (L) < 34 “Propeller effect” Concluding remarks (4) HMXB
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