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Title: THE FATE OF Cyg X-1: AN EMPIRICAL LOWER LIMIT ON BLACK-HOLE-NEUTRON-STAR MERGER RATE

Abstract

The recent distance determination allowed precise estimation of the orbital parameters of Cyg X-1, which contains a massive 14.8 M{sub Sun} black hole (BH) with a 19.2 M{sub Sun} O star companion. This system appears to be the clearest example of a potential progenitor of a black hole + neutron star (BH-NS) system. We follow the future evolution of Cyg X-1, and show that it will soon encounter a Roche lobe overflow episode, followed shortly by a Type Ib/c supernova and the formation of a neutron star (NS). It is demonstrated that in majority of cases ({approx}> 70%) the supernova and associated natal kick disrupt the binary due to the fact that the orbit expanded significantly in the Roche lobe overflow episode. In the reminder of cases ({approx}< 30%) the newly formed BH-NS system is too wide to coalesce in the Hubble time. Only sporadically ({approx}1%) may a Cyg X-1-like binary form a coalescing BH-NS system given a favorable direction and magnitude of the natal kick. If a Cyg X-1-like channel (comparable mass BH-O star bright X-ray binary) is the only or dominant way to form BH-NS binaries in the Galaxy, then we can estimate the empirical BH-NS merger ratemore » in the Galaxy at the level of {approx}0.001 Myr{sup -1}. This rate is so low that the detection of BH-NS systems in gravitational radiation is highly unlikely, generating Advanced LIGO/VIRGO detection rates at the level of only {approx}1 per century. If BH-NS inspirals are in fact detected, it will indicate that the formation of these systems proceeds via some alternative and yet unobserved channels.« less

Authors:
;  [1];  [2]
  1. Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw (Poland)
  2. Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)
Publication Date:
OSTI Identifier:
22047365
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 742; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BINARY STARS; BLACK HOLES; DETECTION; DISTANCE; GALAXIES; GRAVITATIONAL RADIATION; MASS; NEUTRON STARS; ORBITS; ROCHE EQUIPOTENTIALS; X RADIATION

Citation Formats

Belczynski, Krzysztof, Bulik, Tomasz, and Bailyn, Charles. THE FATE OF Cyg X-1: AN EMPIRICAL LOWER LIMIT ON BLACK-HOLE-NEUTRON-STAR MERGER RATE. United States: N. p., 2011. Web. doi:10.1088/2041-8205/742/1/L2.
Belczynski, Krzysztof, Bulik, Tomasz, & Bailyn, Charles. THE FATE OF Cyg X-1: AN EMPIRICAL LOWER LIMIT ON BLACK-HOLE-NEUTRON-STAR MERGER RATE. United States. https://doi.org/10.1088/2041-8205/742/1/L2
Belczynski, Krzysztof, Bulik, Tomasz, and Bailyn, Charles. 2011. "THE FATE OF Cyg X-1: AN EMPIRICAL LOWER LIMIT ON BLACK-HOLE-NEUTRON-STAR MERGER RATE". United States. https://doi.org/10.1088/2041-8205/742/1/L2.
@article{osti_22047365,
title = {THE FATE OF Cyg X-1: AN EMPIRICAL LOWER LIMIT ON BLACK-HOLE-NEUTRON-STAR MERGER RATE},
author = {Belczynski, Krzysztof and Bulik, Tomasz and Bailyn, Charles},
abstractNote = {The recent distance determination allowed precise estimation of the orbital parameters of Cyg X-1, which contains a massive 14.8 M{sub Sun} black hole (BH) with a 19.2 M{sub Sun} O star companion. This system appears to be the clearest example of a potential progenitor of a black hole + neutron star (BH-NS) system. We follow the future evolution of Cyg X-1, and show that it will soon encounter a Roche lobe overflow episode, followed shortly by a Type Ib/c supernova and the formation of a neutron star (NS). It is demonstrated that in majority of cases ({approx}> 70%) the supernova and associated natal kick disrupt the binary due to the fact that the orbit expanded significantly in the Roche lobe overflow episode. In the reminder of cases ({approx}< 30%) the newly formed BH-NS system is too wide to coalesce in the Hubble time. Only sporadically ({approx}1%) may a Cyg X-1-like binary form a coalescing BH-NS system given a favorable direction and magnitude of the natal kick. If a Cyg X-1-like channel (comparable mass BH-O star bright X-ray binary) is the only or dominant way to form BH-NS binaries in the Galaxy, then we can estimate the empirical BH-NS merger rate in the Galaxy at the level of {approx}0.001 Myr{sup -1}. This rate is so low that the detection of BH-NS systems in gravitational radiation is highly unlikely, generating Advanced LIGO/VIRGO detection rates at the level of only {approx}1 per century. If BH-NS inspirals are in fact detected, it will indicate that the formation of these systems proceeds via some alternative and yet unobserved channels.},
doi = {10.1088/2041-8205/742/1/L2},
url = {https://www.osti.gov/biblio/22047365}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 742,
place = {United States},
year = {Sun Nov 20 00:00:00 EST 2011},
month = {Sun Nov 20 00:00:00 EST 2011}
}