Introduction

In a groundbreaking study published November 1 on the pre-print server arXiv, an international team of astronomers has shed light on the long-term behavior of quasi-periodic eruptions (QPEs) from a newly identified source known as eRO-QPE2. Remarkably, their findings indicate that these high-energy X-ray bursts exhibit exceptional stability over a period surpassing three and a half years.

Characteristics of Quasi-Periodic Eruptions

Quasi-periodic eruptions are characterized by short, intense bursts of X-ray radiation, which occur periodically from regions near supermassive black holes (SMBHs) situated at the centers of galaxies. Unlike their gentler counterparts, quasi-periodic oscillations (QPOs), QPEs are marked by drastic increases in the X-ray emission rates that hover above a stable baseline, offering a unique window into the dynamics surrounding black holes.

Discovery of eRO-QPE2

eRO-QPE2 was discovered in 2021 by the eROSITA instrument aboard the Spectrum-Roentgen-Gamma (SRG) satellite. It is associated with the galaxy 2MASX J02344872-4419325 and is located at a redshift of 0.0175. Observations from ESA's XMM-Newton satellite have showcased the extraordinary properties of eRO-QPE2, revealing that these eruptions display intrinsic luminosities fluctuating between approximately 0.12 and 1.2 tredecillion erg/s in the range of 0.5 to 2 keV. Notably, the average rise-and-fall duration of these eruptions is about 27 minutes, with the time between peaks averaging 2.4 hours and a duty cycle of 19%.

Research Findings and Analysis

Leading the research, Dheeraj Pasham from the MIT Kavli Institute for Astrophysics and Space Research, along with his team, analyzed XMM-Newton data collected from August 2020 to February 2024—a timeline encompassing 1,277 days. Their results point to an unprecedented stability in the eruption peak luminosity, temperature fluctuations during eruptions, and the quiescent state of the source.

Stability of Eruptions

Interestingly, the calculated mean recurrence time of the QPEs from eRO-QPE2 stood at 2.35 hours and remained consistent between 2022 and 2024, despite showing a minor decay of roughly six minutes from August 2020 to June 2022. This level of stability sharply contrasts with other QPE systems, which typically exhibit decreases in both eruption and quiescent luminosity over similar timeframes.

Uniqueness of eRO-QPE2

The team’s analysis indicates that due to its quick recurrence times, eRO-QPE2 has experienced significantly more eruptions compared to other QPE sources, further highlighting its unique nature and stability in eruptive behavior.

Speculations on Eruption Origins

As for the potential origins of these eruptions, the researchers speculate that a low-mass white dwarf (approximately 0.18 solar masses) might be subjected to partial tidal stripping by a supermassive black hole with a staggering mass of about 230,000 solar masses. However, the team emphasizes that more research is necessary to validate this hypothesis and gain deeper insights into the mechanics driving these fascinating cosmic phenomena.

Conclusion and Future Research

Astronomers are now eager to monitor eRO-QPE2 closely, as ongoing observations could unlock further secrets of black hole interactions and the fundamental processes governing X-ray emissions in the universe. The implications of this study extend beyond eRO-QPE2 itself, potentially influencing our understanding of other galactic dynamics. Keep watching the skies—there's more to discover!