A simulated map of the Milky Way as it appears in gravitational waves has given a strong impression of what future space detectors will observe.
More than 90 gravitational wave events have been detected so far by a trio of ground-based detectors – the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States, Virgo in Italy, and KAGRA in Japan. All of these detected events are star cluster mergers black holes wow Neutron stars In distant galaxies. No gravitational wave events have been found coming from our planet Milky Way.
However, our galaxy is full of so-called ultrasmall binaries, which once existed Binary stars But it has since evolved into a stellar remnant.
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“Binary systems… fill the Milky Way, and we expect many of them to contain compact objects such as… White dwarfs, Neutron stars And black holes “In tight orbits,” said Cecilia Cerenti of the University of Maryland. NASA Goddard Space Flight Centerin statement. “But we need to space Observatory to “hear them” because Gravitational waves Hum at frequencies too low for ground-based detectors.”
Land-Associated observatories such as Lego Capable of detecting gravitational waves with frequencies between 5 and 20,000 Hz. Ultracompact binaries in our galaxy, as they orbit each other and eventually merge, have frequencies in the millihertz range.
There are several space-based gravitational wave detectors in the works. the European Space AgencyThe Laser Interferometer Space Antenna (LISA) is at the forefront, and is expected to be launched in the 2030s, while Chinese scientists also have two mission concepts, TianQin and Taiji, respectively.
Sherenti is part of a team led by Caitlin Zikirkzis of NASA Goddard’s Gravitational Astrophysics Laboratory, who have now simulated the intensity and frequency of gravitational waves emitted by ultracompact binaries in the Milky Way. The resulting image shows how observatories like LISA will be able to study the Milky Way in gravitational waves just as astronomers study it with X-rays. Gamma rays And so on and so on. The simulated image shows ultracompact binaries concentrated in the plane of the Milky Way’s spiral disk and extending outward. Galaxy halo.
“Our image directly resembles the view of the entire sky in a certain type of light, such as visible, infrared or X-ray light,” said team member James Ira Thorpe, also based at NASA Goddard. “The promise of gravitational waves is that we can observe them Universe “In a completely different way, and this photo really brings that to mind.”
So far, astronomers know of only a few ultra-compact binaries with orbital periods of less than an hour, which would place the compact objects close enough together to emit detectable gravitational waves. They are difficult to find, because neutron stars and black holes do not emit much light. This is the place Lisa Coming up: Ultra-small binaries should shine brightly in gravitational waves, allowing LISA to detect tens of thousands of them.
The shorter the orbital period of an ultracompact binary, the higher the frequency and lower the amplitude of the gravitational waves it emits. If they are really close together, there may be some mass transfer between the two objects, which astronomers can follow using optical, X-ray, and gamma-ray telescopes. Scientists refer to this as merging Electromagnetic and observations of gravitational waves as “multiple messages.” Astronomy“.
Details of the simulated image were published in a research paper in Astronomical magazine Last June.
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