Transcript Document 7890396

X-Ray Binaries
and
Super-Star Clusters
Vicky Kalogera
Jeremy Sepinsky
with
Krzysztof Belczynski
Super-Star Clusters
(SSCs)
• Compact, young analog to globular clusters
• Occur frequently in starburst environments
• Masses range from ~104 to ~107 Mo
•
Ages range from a few to tens of Myr
XRB and SSC observations:
Kaaret et al. 2004
NIC2/NIC3 IR
image of M82
: candidate SSCs
x : Chandra point X-ray sources
Distribution of X-Ray point sources
Kaaret et al. 2004
• Lx ≥ (0.5-3)x1036 erg/s
< 1 XRB per cluster!
Distribution of X-Ray point sources
Kaaret et al. 2004
• XRBs closely associated
with star clusters
• Median distance ~30-100 pc
• Lx ≥ 5x1035
Supernova Kicks
and/or
N1569
Cluster
Dynamics
?
erg/s
50%
N5253
< 1 XRB per cluster!
M82
(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
 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 (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 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 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 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 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 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
(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
> 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
> 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!
Present Calculations
 Low-mass
clusters require a large number of
MC realizations to address statistical effects:
2,000
1,000
1,000
100
10
for
with
with
for
for
~5x104 Mo
f(m)  m-2.7
f(m)  m-2.35
~5x105 Mo
~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