ASKAP J173608.2−321635

Lore & Background

The object was detected six times during radio observations near the center of the Milky Way in 2020, then vanished from areas typically monitored. Follow-up observations in X-ray and near-infrared wavelengths revealed no counterpart, ruling out flaring stars, binary systems, neutron stars, gamma-ray bursts, or supernovae as its source. The radio signal was variable, highly polarized, and difficult to classify.

Mr. Wang and an international team—including scientists from Australia’s CSIRO, Germany, the United States, Canada, South Africa, Spain, and France—discovered the object using CSIRO’s ASKAP radio telescope in Western Australia, with additional observations via the MeerKAT telescope in South Africa. The research received funding from the Australian Research Council, the U.S. National Science Foundation, the European Research Council, the Natural Sciences and Engineering Research Council of Canada, and the University of Sydney’s Sydney Informatics Hub.

The characteristics of ASKAP J173608.2−321635 are consistent with a highly supersonic neutron star interacting with a changing environment, though its high polarization suggests scattering as a result of a black hole. It is not visible to the most powerful non-radio telescopes.

Reader's Guide

ASKAP J173608.2−321635 is significant because it may represent a new class of astronomical object discovered through radio imaging surveys. Its detection only in radio wavelengths, with no counterpart in X-ray or near-infrared, challenges existing classifications and suggests unknown astrophysical processes. The object's high polarization and variability, along with its transient nature, point to interactions with extreme environments near the Galactic Center. While its characteristics are consistent with a supersonic neutron star, the lack of multi-wavelength counterparts and the possibility of black hole scattering leave its true nature unresolved. This discovery highlights the importance of radio surveys in uncovering phenomena invisible to other telescopes, potentially opening a new window into Galactic Center physics. The international collaboration and funding from multiple agencies underscore the global effort to understand such enigmatic sources.

Did You Know?

• The object is nicknamed 'Andy's Object' after its discoverer, Ziteng (Andy) Wang.
• It was detected six times between January and September 2020, then vanished from monitored areas.
• No counterpart was found in X-ray or near-infrared observations.
• Its radio emissions exhibit a high level of polarization, suggesting scattering as a result of a black hole.