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Title: Dynamical Formation of Low-mass Merging Black Hole Binaries like GW151226

Abstract

Using numerical models for star clusters spanning a wide range in ages and metallicities (Z) we study the masses of binary black holes (BBHs) produced dynamically and merging in the local universe ( z ≲ 0.2). After taking into account cosmological constraints on star formation rate and metallicity evolution, which realistically relate merger delay times obtained from models with merger redshifts, we show here for the first time that while old, metal-poor globular clusters can naturally produce merging BBHs with heavier components, as observed in GW150914, lower-mass BBHs like GW151226 are easily formed dynamically in younger, higher-metallicity clusters. More specifically, we show that the mass of GW151226 is well within 1 σ of the mass distribution obtained from our models for clusters with Z/Z{sub ⊙} ≳ 0.5. Indeed, dynamical formation of a system like GW151226 likely requires a cluster that is younger and has a higher metallicity than typical Galactic globular clusters. The LVT151012 system, if real, could have been created in any cluster with Z/Z{sub ⊙} ≲ 0.25. On the other hand, GW150914 is more massive (beyond 1 σ ) than typical BBHs from even the lowest-metallicity (Z/Z{sub ⊙} = 0.005) clusters we consider, but is within 2 σmore » of the intrinsic mass distribution from our cluster models with Z/Z{sub ⊙} ≲ 0.05; of course, detection biases also push the observed distributions toward higher masses.« less

Authors:
; ; ;  [1]
  1. Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) Physics and Astronomy, Northwestern University, Evanston, IL 60202 (United States)
Publication Date:
OSTI Identifier:
22654534
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 836; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; BLACK HOLES; CLUSTER MODEL; DETECTION; EVOLUTION; GALAXIES; GRAVITATIONAL WAVES; LIMITING VALUES; MASS; MASS DISTRIBUTION; METALLICITY; METALS; RED SHIFT; STAR CLUSTERS; STARS; TIME DELAY; UNIVERSE

Citation Formats

Chatterjee, Sourav, Rodriguez, Carl L., Kalogera, Vicky, and Rasio, Frederic A., E-mail: sourav.chatterjee@northwestern.edu. Dynamical Formation of Low-mass Merging Black Hole Binaries like GW151226. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA5CAA.
Chatterjee, Sourav, Rodriguez, Carl L., Kalogera, Vicky, & Rasio, Frederic A., E-mail: sourav.chatterjee@northwestern.edu. Dynamical Formation of Low-mass Merging Black Hole Binaries like GW151226. United States. doi:10.3847/2041-8213/AA5CAA.
Chatterjee, Sourav, Rodriguez, Carl L., Kalogera, Vicky, and Rasio, Frederic A., E-mail: sourav.chatterjee@northwestern.edu. Mon . "Dynamical Formation of Low-mass Merging Black Hole Binaries like GW151226". United States. doi:10.3847/2041-8213/AA5CAA.
@article{osti_22654534,
title = {Dynamical Formation of Low-mass Merging Black Hole Binaries like GW151226},
author = {Chatterjee, Sourav and Rodriguez, Carl L. and Kalogera, Vicky and Rasio, Frederic A., E-mail: sourav.chatterjee@northwestern.edu},
abstractNote = {Using numerical models for star clusters spanning a wide range in ages and metallicities (Z) we study the masses of binary black holes (BBHs) produced dynamically and merging in the local universe ( z ≲ 0.2). After taking into account cosmological constraints on star formation rate and metallicity evolution, which realistically relate merger delay times obtained from models with merger redshifts, we show here for the first time that while old, metal-poor globular clusters can naturally produce merging BBHs with heavier components, as observed in GW150914, lower-mass BBHs like GW151226 are easily formed dynamically in younger, higher-metallicity clusters. More specifically, we show that the mass of GW151226 is well within 1 σ of the mass distribution obtained from our models for clusters with Z/Z{sub ⊙} ≳ 0.5. Indeed, dynamical formation of a system like GW151226 likely requires a cluster that is younger and has a higher metallicity than typical Galactic globular clusters. The LVT151012 system, if real, could have been created in any cluster with Z/Z{sub ⊙} ≲ 0.25. On the other hand, GW150914 is more massive (beyond 1 σ ) than typical BBHs from even the lowest-metallicity (Z/Z{sub ⊙} = 0.005) clusters we consider, but is within 2 σ of the intrinsic mass distribution from our cluster models with Z/Z{sub ⊙} ≲ 0.05; of course, detection biases also push the observed distributions toward higher masses.},
doi = {10.3847/2041-8213/AA5CAA},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 836,
place = {United States},
year = {Mon Feb 20 00:00:00 EST 2017},
month = {Mon Feb 20 00:00:00 EST 2017}
}