Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo

Abstract

Intermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200 M⊙ and effective aligned spin 0.8 at 0.056 Gpc−3 yr−1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpc−3 yr−1.

Maximum mass of compact stars from gravitational wave events with finite-temperature equations of state

“…However, the relative displacement of points corresponding to a given combination of entropy and electron fraction indicates that the values of the parameters a i , b i entering Eqs. (13), and ( 14) depend on thermodynamic conditions, as expected. (11).…”

“…Among these are the precise pulsar mass determinations from the pulsar timing analysis [1][2][3][4][5], measurements of compact star masses and radii through the x-ray observations of their surface emission [6,7] in particular, the results of the NICER experiment [8,9], and the gravitational wave detection of binary neutron star (BNS) mergers by the LIGO-Virgo collaboration [10,11]. Among the events in the last category, the GW170817 event is currently outstanding, since it has been possible to measure not only the neutron star tidal deformability during inspiral, but also electromagnetic counterparts [12,13]. As a result, the GW170817 event has triggered a large number of works which are aimed at constraining neutron star properties and the EoS, either from the analysis of the tidal deformability alone (see for example [14][15][16][17][18][19][20][21][22]), or from a combination of tidal deformability and the electromagnetic signal [23][24][25][26][27][28][29][30].…”

“…Among the events in the last category, the GW170817 event is currently outstanding, since it has been possible to measure not only the neutron star tidal deformability during inspiral, but also electromagnetic counterparts [12,13]. As a result, the GW170817 event has triggered a large number of works which are aimed at constraining neutron star properties and the EoS, either from the analysis of the tidal deformability alone (see for example [14][15][16][17][18][19][20][21][22]), or from a combination of tidal deformability and the electromagnetic signal [23][24][25][26][27][28][29][30]. Including the information from the electromagnetic signal requires as an input numerical modeling of the merger process, which introduces additional uncertain-ties but, at the same time, broadens the experimental base of the analysis.…”

Dynamical dark energy models in the light of Gravitational-Wave Transient Catalogues

“…Our first task in this work was to present an update analysis of the six dark energy parameterisations using the new GW databases described. We consider current SNeIa (Pantheon)+CC+GW data, the GW data came from the GWTC-1 [37] and GWTC-2 [38] catalogues. With this new database, the ΛCDM had a preference against the six dark energy considered models according to the BIC.…”

“…This second GW catalogue includes N GWTC-2 = 39 candidate GW events, with less than 10% of contamination fraction in the redshift range z ∈ [0.03, 0.8] from the first half of the third observable run [38]. In Table VI from [38] these events measured by LIGO-Virgo are presented with their observational siren distances D S in Gpc 6 and redshifts z, along with other several observational variables, all of them with their corresponding 90% credible variances.…”