Virgo and LIGO have announced the detection of an extraordinarily
massive merging binary system: two black holes of 66 and 85 solar
masses, which generated a final black hole of 142 solar masses. Both the
initial black holes, as well as the remnant, lie in a range of mass that
has never before been observed, either via gravitational waves or with
electromagnetic observations.

The final black hole is the most massive ever detected with
gravitational waves. A crucial aspect is that this remnant belongs to
the class of the so-called intermediate-mass black holes (from a hundred
up to a hundred thousand times the mass of the Sun). Until today, very
few intermediate-mass black-hole candidates have been identified through
electromagnetic observations alone and the remnant of GW190521 is the
first observation of an intermediate-mass black hole via gravitational
waves.

This detection has a number of interesting implications. In particular
it is linked to one of the most fascinating and challenging puzzles for
astrophysicists and cosmologists: the origin of supermassive black holes.

APC teams were involved in the design and construction of the Advanced
Virgo instrument, as well as in the exploitation of scientific data.

The webinar is now scheduled for 1500 CET (0900 EDT, 0600 PDT, 220 JST)
on Thursday September 3rd .
To join on Zoom, you need to pre-register at
https://us02web.zoom.us/j/86896814123.
It is planned to also livestream the webinar to YouTube

For more details, see:

  * Article 1 :
    https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.101102
  * Companion article 2:
    https://iopscience.iop.org/article/10.3847/2041-8213/aba493
  * Official press release:
    https://tds.virgo-gw.eu/?call_file=VIR-0729A-20_GW190521PressReleaseENMainFile.pdf
  * Press release CNRS/IN2P3:
    https://www.cnrs.fr/fr/de-nouvelles-populations-de-trous-noirs-revelees-par-les-ondes-gravitationnelles

Illustration:
https://www.cnrs.fr/sites/default/files/inline-images/GW190521.png