TY - JOUR

T1 - Explodability fluctuations of massive stellar cores enable asymmetric compact object mergers such as GW190814

AU - Antoniadis, John

AU - Aguilera-Dena, David R.

AU - Vigna-Gómez, Alejandro

AU - Kramer, Michael

AU - Langer, Norbert

AU - Müller, Bernhard

AU - Tauris, Thomas M.

AU - Wang, Chen

AU - Xu, Xiao Tian

N1 - Publisher Copyright: © J. Antoniadis et al. 2022.

PY - 2022/1/1

Y1 - 2022/1/1

N2 - The first three observing runs with Advanced LIGO and Virgo have resulted in the detection of binary black hole (BBH) mergers with highly unequal mass components, which are difficult to reconcile with standard formation paradigms. The most representative of these is GW190814, a highly asymmetric merger between a 23 M⊙ black hole (BH) and a 2.6 M⊙ compact object. Here, we explore recent results, suggesting that a sizable fraction of stars with pre-collapse carbon-oxygen core masses above 10 M⊙, and extending up to at least 30 M⊙, may produce objects inside the so-called lower mass gap that bridges the division between massive pulsars and BHs in Galactic X-ray binaries. We demonstrate that such an explosion landscape would naturally cause a fraction of massive binaries to produce GW190814-like systems instead of symmetric-mass BBHs. We present examples of specific evolutionary channels leading to the formation of GW190814 and GW200210, a 24+ 2.8 M⊙ merger discovered during the O3b observing run. We estimate the merger-rate density of these events in our scenario to be O(5%) of the total BBH merger rate. Finally, we discuss the broader implications of this formation channel for compact object populations, and its possible relevance to less asymmetric merger events such as GW200105 and GW200115.

AB - The first three observing runs with Advanced LIGO and Virgo have resulted in the detection of binary black hole (BBH) mergers with highly unequal mass components, which are difficult to reconcile with standard formation paradigms. The most representative of these is GW190814, a highly asymmetric merger between a 23 M⊙ black hole (BH) and a 2.6 M⊙ compact object. Here, we explore recent results, suggesting that a sizable fraction of stars with pre-collapse carbon-oxygen core masses above 10 M⊙, and extending up to at least 30 M⊙, may produce objects inside the so-called lower mass gap that bridges the division between massive pulsars and BHs in Galactic X-ray binaries. We demonstrate that such an explosion landscape would naturally cause a fraction of massive binaries to produce GW190814-like systems instead of symmetric-mass BBHs. We present examples of specific evolutionary channels leading to the formation of GW190814 and GW200210, a 24+ 2.8 M⊙ merger discovered during the O3b observing run. We estimate the merger-rate density of these events in our scenario to be O(5%) of the total BBH merger rate. Finally, we discuss the broader implications of this formation channel for compact object populations, and its possible relevance to less asymmetric merger events such as GW200105 and GW200115.

KW - Binaries: close

KW - Gravitational waves

KW - Stars: black holes

KW - Stars: massive

KW - Stars: neutron

KW - Supernovae: general

U2 - 10.1051/0004-6361/202142322

DO - 10.1051/0004-6361/202142322

M3 - Journal article

AN - SCOPUS:85123221050

VL - 657

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

SN - 0004-6361

M1 - L6

ER -