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

Galactic Center region, 20 Ms, 17-60 keV

Limiting flux ~0.26 mCrab 3.7e-12 erg/s/cm2

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.

Stellar density field

Galactic Center region, 20 Ms, 17-60 keV

Low-Massive X-ray Binaries in Bulge

Revnivtsev et al., 2008

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

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

INTEGRAL view of the GRXE

NIR contours

Krivonos et al. 2006, 2009

Galactic ridgeemission in hardX-rays consists ofemission of millionsof CVs!

Shape of cutoffaverage mass of WDs

<Mwd>~0.5-0.6 Msun

INTEGRALRXTE

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

Cataclysmic Variables

Scale height of Galactic disk population is 130 (+90-50) kpc

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

INTEGRALpoints

RXTE points

Revnivtsev et al. 2008

Density of HMXBs In the Galactic plane

INTEGRAL surveySimple toy model

Lutovinov et al. 2005, 2007

The position of spiral arms(ignored)

Shtykovskiy & Gilfanov 2007

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.

-- measured-- not ID-- predicted

High-Massive X-ray Binaries distribution over the Galactic longitude

Crux Carina

Norma

Cyg

Sgr

Disk without hole

r_disk = 2.2 (+0.6-0.4) kpc

Disk size

dN/dL ~L

Probing the LF (single) slope over Log(L) 33-38

-Gamma

Gamma = 1.3 (+0.3-0.2)Voss & Ajello 2010

Maximum Likelihood HMXB Luminosity Function

delta Likelihood < 1.0

Log

Unrealistic LF shape:Overprediction at low luminosities

Log

Unrealistic LF shape:Underprediction at low luminosities

Like “Propeller effect”

Log

dN/dL~L^1.5Absolutely unrealistic LF shape:

Log

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)

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

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

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