Visionary Endeavors of NASA: Modeling Our Galaxy Via Gravitational Wave Simulations

Utilizing simulated datasets, astrophysicists have portrayed the celestial sphere in the medium of gravitational waves, emphasizing the imperative for orbital observatories to identify binary systems. Forthcoming initiatives such as LISA aim to disclose a multitude of these elusive systems, thereby transforming the landscape of space exploration. (This is based on an artist’s rendering; for actual simulation, refer to the associated video.)

Through the use of simulated datasets, astrophysicists have generated a representation of the celestial sky in terms of gravitational waves—fluctuations in the fabric of space-time produced by objects in orbit. The visualization underlines how forthcoming space-based observatories, anticipated to be operational in the upcoming decade, will augment our grasp of the galactic realm we inhabit.

Beginning in 2015, terrestrial observatories have recognized nearly a hundred instances involving the amalgamation of systems, which include stellar-mass black holes, neutron stars, or combinations thereof. Such signals are often ephemeral, existing for less than sixty seconds, possess elevated frequencies, and emanate from locations well outside our galaxy.

Witness synthesized maps representing gravitational waves emanating from simulated aggregations of compact binary systems. These systems are comprised of white dwarfs, neutron stars, or black holes in closely bound orbits. Future all-sky maps based on authentic data will become feasible once orbital gravitational wave observatories become functional in the subsequent decade. Regions of higher luminosity signify sources emanating stronger signals, while paler hues represent higher-frequency sources. More expansive colored areas denote sources with imprecisely determined positions. An inset elaborates on the gravitational signal’s frequency and strength, in addition to the sensitivity threshold for LISA (Laser Interferometer Space Antenna), an observatory under development through a partnership between the European Space Agency (ESA) and NASA, slated for launch in the 2030s. Credit: NASA’s Goddard Space Flight Center

Cecilia Chirenti, a researcher affiliated with the University of Maryland, College Park, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, stated, “Binary systems are abundant in the Milky Way and are expected to house compact objects such as white dwarfs, neutron stars, and black holes in narrow orbits. However, we necessitate a space-based observatory to detect their low-frequency gravitational waves, which are otherwise unattainable through terrestrial instruments.”

These systems are designated as UCBs (ultra-compact binaries) by astronomers, who predict that future observatories like LISA will identify tens of thousands of such entities. UCBs are customarily elusive; they often manifest as dim in visible light, and only a scant few are known to have orbital periods less than an hour. One of the primary missions of LISA is to discover a considerable number of new UCBs.

An artist’s depiction illustrates LISA Pathfinder, a mission by ESA intended to vet technology for upcoming space-based gravitational wave observatories. LISA aims to build upon the accomplishments of LISA Pathfinder and LIGO. Credit: ESA-C.Carreau

Employing data that imitates the anticipated distribution and gravitational wave signatures of these systems, the research team has devised a methodology to synthesize this data into a comprehensive celestial overview of the galaxy’s UCBs. This methodology is documented in a paper published in The Astronomical Journal.

Goddard astrophysicist Ira Thorpe remarked, “Our visualization can be equated to an all-sky snapshot rendered in a distinct spectrum of light, whether it be visible, infrared, or X-ray frequencies. Gravitational waves offer a revolutionary vantage point to observe the universe, a premise vividly encapsulated by this visualization. I look forward to the day when such an image, constructed from actual LISA data, might adorn a poster or a piece of apparel.”

Reference: “Imaging the Milky Way with Millihertz Gravitational Waves” by Kaitlyn Szekerczes, Scott Noble, Cecilia Chirenti, and James Ira Thorpe, published on June 15, 2023, in The Astronomical Journal.
DOI: 10.3847/1538-3881/acd3f1/meta

Frequently Asked Questions (FAQs) about gravitational waves

More about gravitational waves

• NASA’s Official Website on LISA
• The Astronomical Journal: Imaging the Milky Way with Millihertz Gravitational Waves
• European Space Agency’s LISA Pathfinder Mission
• Goddard Space Flight Center
• University of Maryland, College Park
• Overview of Gravitational Waves
• Article on the Detection of Gravitational Waves
• Binary Star Systems