This suggests LIGO — which is in the midst of upgrades to boost its sensitivity and planning for a new station in India — could eventually be detecting the chirps from
black hole mergers at a rate of anywhere between once per day to once per week.
Not exact matches
Observation of Gravitational Waves from a Binary
Black Hole Merger,
at https://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.116.061102
Other stellar explosions called gamma - ray bursts can also briefly outshine the stars, but the explosive
black -
hole merger sets a mind - bending record, says Kip Thorne, a gravitational theorist
at Caltech who played a leading role in LIGO's development.
With the
black hole merger, general relativity has passed the first such test, says Rainer Weiss, a physicist
at the Massachusetts Institute of Technology (MIT) in Cambridge, who came up with the original idea for LIGO.
By timing the arrivals of the signals
at all three detectors, which differ by milliseconds, researchers were able to determine that the
black hole merger took place somewhere within a 60 - square - degree patch of sky in the Southern Hemisphere.
«We know very well that
black holes can be formed by the collapse of large stars, or as we have seen recently, the
merger of two neutron stars,» said Savvas Koushiappas, an associate professor of physics
at Brown University and coauthor of the study with Avi Loeb from Harvard University.
For this study, Koushiappas and Loeb calculated the redshift
at which
black hole mergers should no longer be detected assuming only stellar origin.
In the scenario shown in the upper panels the star collapses after the
merger and forms a
black hole, whereas the scenario displayed in the lower row leads to an
at least temporarily stable star.
The
merger generates powerful ripples in space called gravitational waves that kick the newly merged
black hole away
at speeds of hundreds or even thousands of kilometres per second.
For the first time, scientists worldwide and
at Penn State University have detected both gravitational waves and light shooting toward our planet from one massively powerful event in space — the birth of a new
black hole created by the
merger of two neutron stars.
«Galaxy
mergers are common, and we think there are many galaxies harboring binary supermassive
black holes that we should be able to detect,» said Joseph Lazio, one of Taylor's co-authors, also based
at JPL.
«The gravitational waves from these supermassive
black hole binary
mergers are the most powerful in the universe,» says study lead author Chiara Mingarelli, a research fellow
at the Center for Computational Astrophysics
at the Flatiron Institute in New York City.
«The fact it repeats rules out — for this object anyway — any of the models that are just one - offs, whether they involve
mergers or evaporating
black holes or something else,» says study co-author James Cordes, an astronomer
at Cornell University.
However, Marc Kamionkowski, a theoretical physicist
at Johns Hopkins University in Baltimore, Maryland, says the signal from the
merger of more - massive
black holes should be stronger and detectable from a greater distance.
When Eleonora Troja got the LIGO notification on 17 August that new gravitational waves had been detected, she dismissed it
at first, assuming it was just another
black -
hole merger, she recalls.
The
mergers that formed NGC 1316 led to an influx of gas, which fuels an exotic astrophysical object
at its centre: a supermassive
black hole with a mass roughly 150 million times that of the Sun.
LIGO has previously spotted
mergers of swirling
black holes with masses tens of times that of the sun (SN Online: 9/27/17); the smaller masses of the orbiting duo pointed the finger
at neutron stars.
«If we assume this is the case, that LIGO caught a
merger of
black holes formed in the early universe, we can look
at the consequences this has on our understanding of how the cosmos ultimately evolved.»
He was also working on other LIGO papers
at the time, including one about an earlier detection of a
black -
hole merger which now needed to be published before it could be eclipsed by the neutron - star
merger announcement.
One of the most important scientific consequences of detecting a
black -
hole merger would be confirmation that
black holes really do exist —
at least as the perfectly round objects made of pure, empty, warped space - time that are predicted by general relativity.
Todd Thompson
at Ohio State University in Columbus and his colleagues argue that UHECRs may instead originate in the
merger of two types of dead star, which gives birth to a
black hole.
The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the
merger of two hefty
black holes at the center of the host galaxy.
«But then we looked closer
at the astrophysics of the actual result, a
merger of two 30 - solar - mass
black holes.
But Goldstein and Racusin said that LIGO is expected to detect more merging
black holes in the coming years, as many as 100 such
mergers per year
at the instrument's peak design sensitivity, Goldstein said.
Judy Racusin, an astrophysicist
at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said during today's press conference that the Fermi team is «cautiously saying [the gamma - ray signal] is potentially associated with the
black hole merger» detected by LIGO.
The fact that several such pristine galaxies turn out to have a small, still - expanding
black hole at their core suggests that
black holes can grow to intermediate size without
mergers, but then need to pool their resources to get much bigger.
«Some supermassive
black holes spin
at more than 90 % of the speed of light, which suggests that they gained their mass through major galactic
mergers.»
Findings from this and two previous discoveries of
black hole mergers are providing the WSU scientists and colleagues
at the Laser Interferometer Gravitational - Wave Observatory (LIGO) an unprecedented glimpse into the early universe and shedding new light on how binary
black holes form.
Since most galaxies in the universe are believed to harbor one supermassive
black hole at their center, the presence of a binary system is conclusive evidence of a galactic
merger.
Furthermore, it also provides evidence that suggests that
at least one of the
black holes may have been tilted away from the orbital plane
at the time of the
merger, the study authors added.
The very first detection of gravitational waves on 14 September 2015: Signals received by the LIGO instruments
at Hanford, Washington (left) and Livingston, Louisiana (right) and comparisons of these signals to the signals expected due to a
black hole merger event.
This event, detected by the two NSF - supported LIGO detectors
at 02:01:16 UTC on June 8, 2017 (or 10:01:16 pm on June 7 in US Eastern Daylight time), was actually the second binary
black hole merger observed during LIGO's second observation run since being upgraded in a program called Advanced LIGO.
«We believe that the two supermassive
black holes in this galaxy will merge,» said Karishma Bansal, a graduate student
at UNM, adding that the
merger will come
at least millions of years in the future.
Until that moment, gravitational wave detectors had only discerned the
merger of
black holes billions of light - years away, so to measure a weak signal
at a comparatively close distance came as a surprise.
The signal also closely matched that predicted by supercomputer models of
black -
hole mergers, said LIGO Scientific Collaboration spokeswoman Gabriela Gonzalez, a professor of physics and astronomy
at Louisiana State University.
We'll see how the authors explored the ramifications of throwing several unassociated
black hole (BH) «strangers» into the mix (it's complicated — accretion, three - body interactions, and more are
at play in mediating
mergers), and what it could mean in the context of recent GW discoveries.
He says that if there is a galaxy with an unusually large
black hole at its center, this could have been the result of a supermassive
black hole merger.
When gravitational waves are detected the conditions of the colliding
black holes at the time of the
merger can be studied.
It is beyond awesome that we little lumps of protoplasm squinting out
at the Universe from our shaky platform in the outskirts of an insignificant galaxy can, after four decades of indefatigable effort, detect and characterize a
black hole merger over a billion light years away.