LIGO_O3a Catalog

LIGO and Virgo report on all the compact binaries found in the first half of the latest observing run (O3a): GWTC-2..
We find a few pretty massive binary BHs, like GW190521; a few fairly massive BH that are significantly spinning, like GW190517; a few asymmetric binaries, like the previously-reported GW190814 and GW190412; and a few binaries with one or more object below 3 times the mass of our sun, and therefore potentially neutron stars.

One interesting find was a marginal NSBH candidate (false alarm rate of order 1/yr) GW190426. This event was followed up extensively with optical telescopes. For marginal events like this, we have a hard time corroborating the nature of either component – the GW signature of matter is easier to discern for two neutron stars, with a loud signal.

Last but not least, we find tantalizing suggestions of precession, though we don’t see compelling evidence for spin from any one event.

For experts:Why should you care? More events like GW190521 suggest it isn’t an outlier, but part of a population of larger BH that challenge the traditional “mass gap” boundary. Large spins on objects like GW190517 challenge natal spin models for isolated binaries, which must both explain a preponderance of events near zero at all masses and a few high-mass events with large spin. Support for precession from measuring chi_eff (some definitely can be negative) and chi_p (some have nonzero values) suggests at least some events are strongly precessing.

For more information:

• GWTC-2 catalog, submitted to PRX, with a public data release available at LIGO DCC; see also the GW open science center.

• Population properties of compact objects from the second LIGO–Virgo Gravitational-Wave Transient Catalog, with an embedded data release.

You can find all of the papers which LIGO and Virgo released this week at papers.ligo.org.

RIFT and the O3a catalog: Our parameter inference code RIFT was used to compare gravitational wave observations to the data. Jake’s thesis (under embargo until Dec 1) included some of the O3a PE.