spatial distribution of luminous x-ray binaries in galaxies
DESCRIPTION
Spatial distribution of luminous X-ray binaries in galaxies. introduction. Chandra observations have revolutionized XRB studies with the discovery of large numbers of point X-ray sources in galaxies even beyond the Local Group (Fabbiano et al. 2003) - PowerPoint PPT PresentationTRANSCRIPT
Spatial distribution of luminous X-ray binaries in galaxies
introduction
• Chandra observations have revolutionized XRB studies with the discovery of large numbers of point X-ray sources in galaxies even beyond the Local Group (Fabbiano et al. 2003)
• Cumulative X-ray luminosity functions analysis (Grimm et al. 2003;Zezas & Fabbiano 2002)
• Spatial distribution of luminous XRBs (Jonker et al. 2004; Grimm et al. 2002; Temple et al. 2005).
Methods
Luminosity function
(1)Luminosity Calculation:2cMLbol
(Belczynski 2003)
(3) If a MS donor star is three times massive than the accretor, let the binary coalescence.(?)
(2)
(4) Critical luminosity:• For kw2=0-9 :
• For kw2=10-12(WD) ：
BH
NS
hrP
hrP
L
L
sun
critX
)/lg(07.122.2
)/lg(07.162.1)log( ,
(5) Magnetic Braking:
(6)the mass of NS and BH
(7)
(8) During the SN explosions, a kick velocity vk is imparted on the newborn compact stars with the Maxwellian distribution:
Spatial distribution of X-ray binaries
• born uniformly in the young Galactic disk(z = 70pc), Rmin = 0 out to Rmax = 15Kpc
• born uniformly during the past 12Gyr• the direction of the initial velocity vector was cho
sen randomly• integrated motion equations with a fourth-order
Runge-Kutta method
Result
Observation
high luminosity cut-off of the LMXB XLF and power-law distribution of the HMXB XLF
Combined luminosity function of compact X-ray sources in the starburst galaxies M82, NGC 4038/9, NGC 4579, NGC
4736 and Circinus with a total SFR of 16 M /yr⊙
the radial distribution of LMXBs is modified by the effect of the galactic potential.
The radial distribution of XRBs is constructed by the combination of H-XRBs and He-XRBs, where H-XRBs can be modified greatly by the galactic potential while He-XRBs can not.
The radial distribution of ULXs in starburst galaxies directly reflects the birth radial distribution.
Vertical distributions of HMXBs&LMXBs in the luminosity interval Log(LX) = [37, 38] in the Milky Way
LMXBs
Log Lx=[37,38]
Log Lx=[38,39]
HMXBs
Log Lx=[37,38]
Log Lx=[38,39]
conclusion
• the more luminous the XRBs are, the more concentrated they are towards the Galactic plane.
• persistent sources are more concentrated towards the Galactic plane than transient ones.
• LMXBs in the luminosity range of 10^37 -10^38 erg/s show clear concentrations towards the Galactic buldge and include a number of sources at high Galactic z while others do not.
• BH-XRBs are more concentrated towards the Galactic plane than NS-XRBs
• He-XRBs are more concentrated towards the Galactic plane than H-XRBs
• the radial distribution of LMXBs and HMXBs is modified by the effects of the galactic potential.