Solitary supermassive black holes, located at the centers of galaxies residing in isolation, are much more ferocious “eaters” of stellar material than their counterparts populating more crowded zones of cosmic space, new research has revealed.
To dig deeper into how black holes feed on stellar material, Anish Aradhey, a student at the Harrisonburg High School in Virginia and Anca Constantin, a professor of astrophysics at James Madison University, observed data from the Sloan Digital Sky Survey (SDSS) and NASA’s Wide-field Infrared Survey Explorer (AllWISE/NEOWISE) space telescope. It was the changing brightness of the over 290,000 galaxies they studied that led them to reveal that over 20,000 black holes that were "feeding" actively on surrounding gas and dust had not been detected earlier.
This is because the studies had been utilizing optical or mid-infrared wavelengths. The so-called reclusive, or void galaxies which play host to a lot of star formations, emit bluer light emissions. It is these latter that are able to "drown out" the light emanating from feeding black holes.
“Quantifying variations in the mid-infrared light of galaxies has the potential to detect black holes that traditional methods miss,” said Aradhey.
Now, the fluctuations in brightness of infrared light home in on the frenzy-feeding of black holes. Furthermore, it was discovered that they were displaying more activity in small or medium-size galaxies than large ones.
"The smaller galaxies seem to snack more effectively, if you will, when they are left alone and they don't interact with their neighbors," Aradhey said in a statement. Co-author Anca Constantin added:
"These findings challenge our current understanding of how galaxies evolve. They show that in these reclusive galaxies, the fuel generally available for star formation is channeled towards the central black hole somewhat more efficiently than in similar galaxies in the more crowded environments.”