We might have a new method for seeking intermediate-mass black holes stuck in the heart of galaxies.
Fresh X-ray observations from the Chandra X-Ray Observatory spotted the likely signatures of black stars in dense star clusters, in at least 29 galaxies among a survey of 108 of these star collections.
These compact star groupings, known as nuclear star clusters, are present in most lower-mass galaxies. Before this study, scientists couldn’t predict if any black holes were present, because their signatures were hard to spot.
This finding could at last help span an evolutionary gap in black hole science, between the smallest ones that are roughly the mass of a large star, to the most massive ones that can occupy huge galaxies like our own Milky Way.
Since we’ve had little luck so far finding intermediate-mass black holes, the hope is this study could shed more light on how black holes of roughly 100 to 100,000 solar masses form and continue to evolve.
“One of the prevailing theories out there is that massive black holes could only have formed during the early universe when things were more dense,” Vivienne Baldassare, lead author of the study and an assistant professor of physics and astronomy at Washington State University, said in a university statement.
“Our research is more consistent with the picture where massive black holes don’t need to form in the very early universe, but could rather continue to form throughout cosmic time in these particular environments.”
Chandra, which has the advantage of being located in space and far away from the atmospheric interference of Earth, will be tasked shortly to find more of these intriguing objects. The researchers will do more X-ray measurements to better pinpoint under what specific conditions these lower-mass black holes form.
A study based on the journal was published in the Astrophysical Journal.