A simulated map of the Milky Way as it appears in gravitational waves has given a powerful impression of what future space-based detectors will observe.
More than 90 gravitational wave phenomena have been detected so far by a triumvirate of ground-based detectors: the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States, Virgo in Italy, and KAGRA in Japan.These detected events are all mergers of stellar masses Black Hole and/or neutron star In a galaxy far away.No gravitational wave events have been discovered coming from our Earth milky way galaxy.
However, our galaxy is filled with so-called microbinaries. Binary star However, it later evolved to become the remains of a star.
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“Binary star systems…fill the Milky Way, and many are expected to contain compact objects such as: white dwarf, neutron star and Black Hole It’s in a narrow orbit,” said Cecilia Quilenti of the University of Maryland. NASA’s Goddard Space Flight Center,in statement. “But we have space The observatory is there to “hear” them. gravitational waves It’s a hum at a frequency too low for ground-based detectors. ”
earthlimited to observatories such as Lygo It can detect gravitational waves with frequencies between 5 and 20,000 hertz. The microbinary stars in our galaxy have frequencies in the millihertz range because they spiral around each other and eventually merge.
Several space-based gravitational wave detectors are under development.of european space agency‘s Laser Interferometer Space Antenna (LISA) is at the forefront, with launch expected in the 2030s, but Chinese scientists also have two mission concepts, named Tianqin and Taiji, respectively.
Cilenti is part of a team led by Caitlin Shekelches at NASA’s Goddard Institute for Gravitational Astrophysics, which is currently simulating the strength and frequency of gravitational waves emitted by microbinary stars in the Milky Way. The resulting images show how observatories such as LISA can study the Milky Way with gravitational waves, just as astronomers study it with his X-rays. gamma ray and so on. The simulated image shows an ultra-compact binary star concentrated in the face of the Milky Way’s spiral disk and spilling out into the Milky Way. galaxy halo.
“Our images directly resemble an all-sky view of the sky with specific types of light, such as visible light, infrared light, and X-rays,” said team member James, also based at NASA Goddard. Ira Thorpe said. “The promise of gravitational waves is that we can observe them. macrocosm This image really reminds me of that, in a completely different way. ”
To date, the only microbinary stars known to astronomers have orbital periods of less than an hour and may be close enough to each other to emit detectable gravitational waves. Neutron stars and black holes are difficult to spot because they don’t emit much light.Here is Lisa Ultracompact binaries radiate brightly with gravitational waves, which should enable LISA to discover tens of thousands of binaries.
The shorter the orbital period of a microbinary star, the higher the frequency and the smaller the amplitude of the gravitational waves it emits. If they are really close, there may even be mass transfer between the two objects that astronomers could track with optical, X-ray, or gamma-ray telescopes. Scientists refer to this fusion. electromagnetic Gravitational wave observation as a “multi-messenger” astronomy. ”
For details on the simulation image, see astronomical journal Last June.