An international team of astronomers has made a groundbreaking discovery in the cosmic realm, unveiling an exceptionally bright and rapid cosmic burst originating from a small galaxy approximately 500 million light-years away. Led by Dr. Claudia Gutiérrez from the Institute of Space Studies of Catalonia and the Institute of Space Sciences, this discovery is documented in the prestigious The Astrophysical Journal.

The cosmic burst, designated as CSS161010, exhibited a stunning increase in brightness, reaching its peak in just four days and swiftly diminishing to half its luminosity within 2.5 days. This rapid evolution posed significant challenges but also marked a remarkable milestone in observational astronomy, allowing the team to witness such swift changes in real time.

First detected by the Catalina Real-Time Transient Survey, with earlier observations from the All-Sky Automated Survey for SuperNovae, follow-up investigations were conducted using advanced telescopes, including the Gran Telescopio Canarias (GTC) and the Nordic Optical Telescope (NOT) at the Roque de Los Muchachos Observatory in La Palma, Spain.

Understanding these fleeting cosmic events has always been a challenge due to their nature. However, recent advancements in observational techniques and instruments have enabled astronomers to capture high-resolution images and broaden their field of view, facilitating the study of rapid phenomena like CSS161010.

The research team, which includes leading astronomers such as Professor Seppo Mattila from the University of Turku, suspects that this incredible burst results from a small black hole exerting gravitational force on a star. Their analysis of unique spectral properties displayed by CSS161010 may finally reveal clues about its physical origins. They noted broad hydrogen lines indicating extraordinary speeds up to 10% that of light and observed an unprecedented change in brightness, which had decreased a staggering 900 times just two months after the outburst.

Adding to the intrigue, spectra captured by the Gran Telescopio Canarias indicated that all hydrogen lines remained blueshifted, suggesting a powerful outflow of gas directed towards Earth—a feature that challenges conventional expectations for supernovae events.

"It's a thrilling yet daunting experience discovering and analyzing these cosmic explosions due to their rapid evolution," Dr. Gutiérrez remarked. "Our swift scientific response enabled us to gather high-quality data that illuminated unique characteristics, marking this as an extraordinary event in our studies."

The galaxy, where the burst occurred, contains a mass about 400 times smaller than our Milky Way's, hinting that if it does harbor a black hole, its mass must also be relatively small, potentially classifying it as an intermediate-mass black hole. These elusive structures, with masses ranging between 100 and 100,000 solar masses, remain largely mysterious, with only a handful of confirmed instances, according to Professor Mattila.

"Identifying and characterizing these intermediate-mass black holes is crucial for understanding their formation pathways, which is essential in piecing together the puzzle of supermassive black holes located at the centers of galaxies, including our own,” Mattila explains.

Additionally, Professor Peter Lundqvist from Stockholm University noted that the emission evolution observed in CSS161010 bears a striking resemblance to that found in active galactic nuclei harboring supermassive black holes. This connection strongly indicates that CSS161010 resides in a galaxy with such a black hole, albeit one that isn't particularly massive.

The violent demise of a star too close to this intermediate-mass black hole has dramatically revealed its presence, offering astronomers a golden opportunity to study such phenomena. Lundqvist emphasized, "There are likely many more similar black holes tucked away in other dwarf galaxies, and tracking events akin to CSS161010 is vital for refining our understanding of their properties.”

As we stand on the brink of uncovering more cosmic secrets, the team now looks toward future observations that could unlock further mysteries behind black holes and their captivating interactions with the stars around them.