Vicky KalogeraJeremy Sepinsky

withKrzysztof Belczynski

X-Ray BinariesX-Ray Binaries and and Super-Star ClustersSuper-Star Clusters

Super-Star Clusters (SSCs)

• Compact, young analog to globular clusters• Occur frequently in starburst environments

• Masses range from ~104 to ~107 M

•Ages range from a few to tens of Myr

: candidate SSCs x : Chandra point X-ray sources

XRB and SSC observations:

Kaaret et al. 2004NIC2/NIC3 IR image of M82

Kaaret et al. 2004

• Lx ≥ (0.5-3)x1036 erg/s

Distribution of X-Ray point sources

< 1 XRB per cluster!

Kaaret et al. 2004

• Lx ≥ 5x1035 erg/s

Distribution of X-Ray point sources

• XRBs closely associated with star clusters• Median distance ~30-100 pc

< 1 XRB per cluster!M82N5253

N1569

50%

Supernova Kicks Supernova Kicks and/orand/or

Cluster Dynamics ?Cluster Dynamics ?

StarTrack code (Belczynski et al. 2002 and 2004)

Tracks evolution of binaries and single stars (Hurley et al.)

Detailed calculations of mass transfer rate

Integrated tidal evolution

Asymmetric core collapse and mass range for NS / BH

Angular momentum and mass losses

Calibrated against open-cluster and XRB observations

and mass transfer calculations

(1) XRB Population Syntheses

StarTrack code (Belczynski et al. 2002 and 2004)

Tracks evolution of binaries and single stars Tracks evolution of binaries and single stars (Hurley et al.)

Detailed calculations of mass transfer rate

Integrated tidal evolution

Assymetric core collapse and mass range for NS / BH

Angular momentum and mass losses

Calibrated against open-cluster and XRB observations

and mass transfer calculations

(1) XRB Population Syntheses

StarTrack code (Belczynski et al. 2002 and 2004)

Tracks evolution of binaries and single stars (Hurley et al.)

Detailed calculations of Detailed calculations of mass transfer ratemass transfer rate

Integrated tidal evolution

Assymetric core collapse and mass range for NS / BH

Angular momentum and mass losses

Calibrated against open-cluster and XRB observations

and mass transfer calculations

(1) XRB Population Syntheses

StarTrack code (Belczynski et al. 2002 and 2004)

Tracks evolution of binaries and single stars (Hurley et al.)

Detailed calculations of mass transfer rate

Integrated Integrated tidal evolutiontidal evolution

Assymetric core collapse and mass range for NS / BH

Angular momentum and mass losses

Calibrated against open-cluster and XRB observations

and mass transfer calculations

(1) XRB Population Syntheses

StarTrack code (Belczynski et al. 2002 and 2004)

Tracks evolution of binaries and single stars (Hurley et al.)

Detailed calculations of mass transfer rate

Integrated tidal evolution

Assymetric core collapse and mass range for NS / BHAssymetric core collapse and mass range for NS / BH

Angular momentum and mass losses

Calibrated against open-cluster and XRB observations

and mass transfer calculations

(1) XRB Population Syntheses

StarTrack code (Belczynski et al. 2002 and 2004)

Tracks evolution of binaries and single stars (Hurley et al.)

Detailed calculations of mass transfer rate

Integrated tidal evolution

Assymetric core collapse and mass range for NS / BH

Angular momentum and mass lossesAngular momentum and mass losses

Calibrated against open-cluster and XRB observations

and mass transfer calculations

(1) XRB Population Syntheses

StarTrack code (Belczynski et al. 2002 and 2004)

Tracks evolution of binaries and single stars (Hurley et al.)

Detailed calculations of mass transfer rate

Integrated tidal evolution

Assymetric core collapse and mass range for NS / BH

Angular momentum and mass losses

CalibratedCalibrated against open-cluster and XRB observations against open-cluster and XRB observations

and mass transfer calculationsand mass transfer calculations

(1) XRB Population Syntheses

(2) Orbital Evolution in SSCs

Isolated XRBs evolved in a static Plummer potential > self-consistent initial positions and velocities

Position, X-Ray Luminosity, and Evolutionary Status are simultaneously tracked through 200 Myr

Dynamical interactions and an evolving cluster potential are NOT included!

(2) Orbital Evolution in SSCs

Isolated XRBs evolved in a static Plummer potential Isolated XRBs evolved in a static Plummer potential > self-consistent initial positions and velocities> self-consistent initial positions and velocities

Position, X-Ray Luminosity, and Evolutionary Status Position, X-Ray Luminosity, and Evolutionary Status are simultaneously tracked through 200 Myrare simultaneously tracked through 200 Myr

Dynamical interactions and an evolving cluster potential are NOT included!

(2) Orbital Evolution in SSCs

Isolated XRBs evolved in a static Plummer potential > self-consistent initial positions and velocities

Position, X-Ray Luminosity, and Evolutionary Status are simultaneously tracked through 200 Myr

Dynamical interactions and an evolving cluster potential Dynamical interactions and an evolving cluster potential are NOT included!are NOT included!

Present Calculations

Low-mass clusters require a large number ofMC realizations to address statistical

effects: 2,000 for ~5x104 Mo

1,000 with f(m) m-2.7

1,000 with f(m) m-2.35

100 for ~5x105 Mo

10 for ~5x106 Mo

Binaries evolved for 200 Myr Half-mass radius set to 10pc Binary fraction set to 100% (NXRB: upper limits)

Theoretical XRB Distributions

• cluster mass: ~5x104 Mo

• LX > 5x1035 erg/s• average of 1,000 clusters

• Significant age dependence

• < 1 XRB per cluster

More Massive Clusters

• cluster mass: ~5x105 Mo

• LX > 5x1035 erg/s• average of 100 clusters

• Similar age dependence

• Mean XRB number /cluster

~ cluster mass

Conclusions

XRB models without cluster dynamics appear in agreement with observations

Mean XRB number per SSC < 1 and spatial distribution: M < 105 Mo and 10-50Myr or more massive and ~50Myr Supernova kicks: eject XRBs @ D > 10pc

especially for M < 105 Mo

• Results do not appear sensitive to binary evolution assumptions, but extended parameter study is needed.• Explore role of dynamics