Distant "Gigamaser" Discovered 8 Billion Light-Years Away by MeerKAT Telescope

Astronomers utilizing the MeerKAT telescope in South Africa have detected the brightest and most distant hydroxyl megamaser to date, located approximately 8 billion light-years from Earth.

Originating from a merging galaxy system, this powerful microwave emission was made detectable through the phenomenon of gravitational lensing and has been proposed for classification as a "gigamaser."

Discovery Details

The detected signal emanates from a pair of colliding galaxies, specifically HATLAS J142935.3–002836, which were initially identified in 2014. The microwaves, measuring approximately 18 centimeters (1,665 megahertz), were emitted when the universe was about half its current age.

Researchers estimate the maser's luminosity to be 100,000 times that of a typical star, concentrated within a narrow segment of the electromagnetic spectrum. Its light traveled approximately 7.82 billion light-years to reach Earth.

Thato Manamela, an astronomer at the University of Pretoria in South Africa and the study's first author, emphasized the significance of observing a radio signal from such an extreme distance.

The Role of Gravitational Lensing

The detection and subsequent analysis of this exceptionally distant maser were greatly facilitated by gravitational lensing. This phenomenon, a prediction of Albert Einstein's theory of relativity, occurs when electromagnetic radiation from a distant source is bent and magnified. This magnification happens due to the gravity of a massive object positioned between the source and the observer.

In this specific instance, a foreground galaxy acted as a gravitational lens, effectively amplifying the microwaves. This amplification was crucial, allowing the MeerKAT telescope — an array of 64 radio antennae — to detect the signal, which would have otherwise been too faint.

Understanding Cosmic Masers

The term "maser" is an acronym for "microwave amplification by stimulated emission of radiation." Much like lasers, masers produce focused beams of light, but these occur at microwave frequencies.

Hydroxyl megamasers specifically form during the merger of two galaxies. These cosmic collisions compress vast gas clouds, which in turn excite hydroxyl (OH) molecules. The excited molecules then release high-energy microwaves, generating the distinct maser emission.

Due to its unparalleled brightness and power, researchers have proposed classifying this newly discovered emission as a "gigamaser." This classification represents a higher theoretical order of magnitude. Gigamasers are considered even rarer than megamasers and can be billions of times brighter than standard masers.

Significance and Future Research

Megamasers and gigamasers are infrequent phenomena that offer astronomers valuable insights into the formation, growth, and evolution of ancient galaxies. The discovery of this gigamaser sets a new record, surpassing a previous distance record of 5 billion light-years for such a system.

This achievement demonstrates the MeerKAT telescope's exceptional capability to study high-redshift hydroxyl megamasers. This capability is expected to significantly contribute to our understanding of galaxy outflows and merging activities in the early universe.

The research team plans to continue utilizing MeerKAT to investigate similar systems. Their objective is to discover more megamasers or gigamasers within gravitationally lensed objects, a strategy aimed at substantially increasing the number of these cosmic phenomena available for study.

Publication Details

The findings of this groundbreaking research were submitted to arXiv on February 13 and have been accepted for publication in Monthly Notices of the Royal Astronomical Society: Letters.