J/ApJ/716/615 Binary compact object coalescence rates (O'Shaughnessy+, 2010)
Binary compact object coalescence rates: the role of elliptical galaxies.
O'Shaughnessy R., Kalogera V., Belczynski K.
<Astrophys. J., 716, 615-633 (2010)>
=2010ApJ...716..615O 2010ApJ...716..615O
ADC_Keywords: Pulsars ; Models, evolutionary ; Galaxies, nearby
Keywords: binaries: close - gravitational waves - pulsars: general
Abstract:
In this paper, we estimate binary compact object merger detection
rates for LIGO, including the potentially significant contribution
from binaries that are produced in elliptical galaxies near the epoch
of peak star formation. Specifically, we convolve hundreds of model
realizations of elliptical- and spiral-galaxy population syntheses
with a model for elliptical- and spiral-galaxy star formation history
as a function of redshift. Our results favor local merger rate
densities of 4x10-3Mpc-3/Myr for binary black holes (BHs),
3x10-2Mpc-3/Myr for binary neutron stars (NSs), and
10-2Mpc-3/Myr for BH-NS binaries. Assuming a detection
signal-to-noise ratio threshold of 8 for a single detector (in
practice as part of a network, to reduce its noise), corresponding to
radii Dbns of the effective volume inside of which a single LIGO
detector could observe the inspiral of two 1.4M☉ NSs of 14Mpc
and 197Mpc, for initial and advanced LIGO, we find event rates of any
merger type of 2.9x10-2-0.46 and 25-400yr-1 (at 90% confidence
level), respectively.
Description:
To summarize, by fully simulating the past history of the local
universe, this paper develops models for the present-day detection
rate of short-range (z≪1) and long-range (z not much less than 1)
gravitational-wave detectors. Our results are rate distributions,
where each distribution includes some normalization uncertainties (SFR
and fraction of stars born in binaries), certain population synthesis
model parameters, and our simulation Monte Carlo uncertainty.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 159 489 Parameters of all binary evolution simulations
used in this paper, along with predicted merger
rates R, detection rates R, and (for spiral
simulations) posterior probabilities
--------------------------------------------------------------------------------
See also:
J/ApJ/713/671 : Gravitational waves from pulsars (Abbott+, 2010)
J/ApJ/675/1459 : Compact Binary Coalescence Galaxy Catalog (Kopparapu+, 2008)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- T [E/S] Galaxy type (E)lliptical or (S)piral
3- 6 F4.2 Sun Z Metallicity relative to the Sun
8- 12 F5.2 --- p Inital Mass Function slope
14- 17 F4.2 --- r Mass ratio distribution exponent (1)
19- 22 F4.2 --- w Wind strength
24- 29 F6.2 km/s v1 Maxwellian velocity dispersion 1 (2)
31- 36 F6.2 km/s v2 Maxwellian velocity dispersion 2 (2)
38- 41 F4.2 --- wt [0/1] Relative proportions of two o
maxwellian distributions
43- 46 F4.2 --- alpha [0/1] α*λ, the common
envelope efficiency
48 I1 --- beta [1] Specific angular momentum of matter
lost (3)
50- 53 F4.2 --- fa Nonconservative mass transfer fraction
accreted (4)
55- 62 I8 --- N Number of binaries simulated
64- 69 I6 --- N(bh-hb) Number of BH-BH binaries formed
71- 75 I5 --- N(bh-ns) ? Number of BH-NS binaries formed (5)
77- 82 I6 --- N(ns-ns) ? Number of NS-NS binaries formed (5)
84- 86 I3 --- m(bh-bh) Number of BH-BH binaries that merge
within 13.7 Gyr
88- 92 I5 --- m(bh-ns) ? Number of BH-NS binaries that merge
within 13.7 Gyr (5)
94- 98 I5 --- m(ns-ns) ? Number of NS-NS binaries that merge
within 13.7 Gyr (5)
100-104 F5.2 [Myr-1/Mpc3] r(bh-bh) Log Rate density for BH-BH mergers (6)
106-110 F5.2 [Myr-1/Mpc3] r(bh-ns) ? Log Rate density for BH-NS mergers (7)
112-116 F5.2 [Myr-1/Mpc3] r(ns-ns) ? Log Rate density for BH-NS mergers (5,7)
118-122 F5.2 [Myr-1/Mpc3] r*(bh-bh) Log Rate density for BH-BH mergers (8)
124-128 F5.2 [Myr-1/Mpc3] r*(bh-ns) ? Log Rate density for BH-BH mergers (8)
130-134 F5.2 [Myr-1/Mpc3] r*(ns-ns) ? Log Rate density for BH-BH mergers (5,8)
136-140 F5.2 yr-1 R(bh-bh) LIGO detection rate for BH-BH
mergers (9)
142-146 F5.2 yr-1 R(bh-ns) ? LIGO detection rate for BH-NS
mergers (9)
148-152 F5.2 yr-1 R(ns-ns) ? LIGO detection rate for NS-NS
mergers (9)
154-159 F6.4 --- Ppost ? Posterior probability factor (10)
--------------------------------------------------------------------------------
Note (1): p(q)∼q(-r) at large q.
Note (2): for two-component velocity distribution.
Note (3): Podsiadlowski et al (1992ApJ...391..246P 1992ApJ...391..246P).
Note (4): see Belczynski et al (2002ApJ...572..407B 2002ApJ...572..407B) Eq. 9.
Note (5): Black Hole (BH) / Neutron Star (NS) lergers.
Blank entries are not provided or used in this work, per the
discussion near Fig. 9 and in PSgrbs. These simulations have few
merging binaries of one type or another.
Note (6): At present, due to this model, assuming the star formation history
associated with type type (E or S).
Note (7): At present. Provided only for the 250+ models where the rates are
drawn from an unbiased distribution, per the discussion near Fig. 9
and in PSgrbs.
Note (8): At present, due to this model, assuming all star formation occurs
according to this model.
Note (9): Expected single-interferometer initial LIGO detection rate. The
single-interferometer advanced LIGO detection rate incorporates the
time-dependent merger history and cosmological reach of the detector.
The ratio of initial to advanced detection rates is nearly constant
for BH-NS and NS-NS binaries; only for BH-BH binaries are corrections
significant.
Note (10): Only provided for the 241 (out of 282) spiral galaxy models where
BH-BH, BH-NS, and NS-NS merger rates are each drawn from an unbiased
distribution, per the discussion near Fig. 9 and in PSgrbs.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 30-May-2012