How quickly will Advanced LIGO/Virgo be able to detect a gravitational wave, and how precisely will they be able to tell their partner electromagnetic telescopes where to point? Today’s authors answer these questions for the most promising and best-understood type of system, binary neutron star mergers. Specifically, they take a realistic look at LIGO/Virgo’s first two online years, including their early sensitivity and expected downtime.
Gravitational waves passing through our solar system make the Sun ring like a bell. Can their effect be measured to learn about the violent phenomena that caused them?
Imagine a spinning skater. She pulls her arms in a little and spins faster. She brings her arms all the way into her chest, and spins really fast, and then bam! she rockets up into the sky. Seven years ago, computer simulations revealed a configuration of two spinning black holes that merged in this way, jumping out of their orbital plane with a velocity of several thousand km/s. Not only is this weird, it’s also important. We know that large galaxies host supermassive black holes at their centers. We also know that galaxies merge, presumably introducing their black holes to one another. If the newly formed black hole were to exit the galaxy entirely, it could carry its accretion disk with it, and be observable as a displaced core.
Null data are still data! Chen & Holz use a lack of detections to place a lower limit on the beaming angle of SGRBs.
Short gamma-ray bursts, extremely energetic explosions in the Universe, might be caused by the merger of two compact objects. In the two papers we discuss today, the authors test this scenario by looking for light emitted still a few days after the explosion.
The race to be the first to detect gravitational waves is on – are pulsar timing arrays on the verge of a discovery? New predictions based on revised galaxy merger calculations suggest that it may be so.