An artist’s interpretation of the radiation and gas jets emitted from a galaxy’s central supermassive black hole. (Source: NASA)
Researchers at Keele University have found a supermassive nuclear black hole that exceeds the size limitations of its host galaxy and has now been proven to be the source of many of the galaxy’s anomalies. Among these is the fact that such a large black hole exists in an apparently relatively younger galaxy (1).
The Earth is a constituent of the Solar System, a group of astronomical bodies revolving around the Sun. The Solar System is part of a larger cluster of such planetary systems and stars, which ultimately compose the Milky Way galaxy. At the center of the Milky Way, there exists a supermassive black hole that exerts the enormous forces that drive the Milky Way’s spiral while steadily consuming the stellar gases that compose the galaxy. Likewise, around the universe there exist other supermassive black holes occupying and driving the centers of their host galaxies (3, 4).
In recent years, a spectroscopic survey initiated by the Spitzer Space Telescope has spent countless hours observing various sources of infrared and ultraviolet radiation located around the Large Magellanic Cloud—a satellite galaxy of the Milky Way (1). This study used the Southern African Large Telescope, the largest optical telescope in the world to measure red shift constants to quantify the rate of expansion and collapse of galaxies. It also used the hydrogen alpha spectrum to measure star formation activity and the mass of nuclear black hole to mass of galaxy ratios to quantify galactic sizes and to justify emission spectra (1,2). One such radiation source, SAGE0536AGN (Active Galactic Nuclei), SAGE0536S (Star), and SAGE0536G (Galaxy), caught the attention of astronomers for its incompatible combination of an oversized black hole and early evolutionary stage galaxy (1).
Recently, Loon et al. investigated the anomalous pairing of an oversized black hole with an early stage galaxy in SAGE0536G. To gauge the star formation activity of the galaxy, researchers analyzed the hydrogen alpha emission spectrum, in particular the red spectral line in the hydrogen Balmer series. In order to calculate the respective masses of the galaxy and its central black hole, researchers monitored the dispersion of the stars in the arms of the galaxy and the red shift of the radiation emitted from SAGE05336AGN (1).
As a result, the researchers found that SAGE0536G lacked star formation activity as indicated by a low hydrogen alpha spectrum, characterizing the galaxy as an early stage galaxy (1). This would have implied that SAGE0536G would only be a few Gigayears old; further analysis of the galaxy’s redshift, however, indicated that SAGE0536G was about nine Gigayears of age (1, 2). Furthermore, careful observation of the spheroid nature of the galaxy led researchers to conclude that SAGE0536AGN was actually a far larger black hole than SAGE0536G had galactic material to maintain (1).
From these observations, the research team rationalized the abnormal ratio of mass for the supermassive black hole SAGE0536AGN and its host galaxy SAGE0536G. Researchers concluded that SAGE0536AGN’s abnormally large size resulted from its constant injection of cooling stellar matter from the host galaxy SAGE0536G (1). Meanwhile, the abnormally small size and lack of star formation activity in SAGE0536G resulted from the negative feedback from the heating caused by the accretion of galactic material to SAGE0536AGN (1). These insights are a start in developing a generalized theory for explaining such abnormal pairings of oversized black holes to optically younger galaxies (1).
References:
- Jacco Th. van Loon, Anne E. Sansom. An evolutionary missing link? A modest-mass early-type galaxy hosting an oversized nuclear black hole. Monthly Notices of the Royal Astronomical Society, 2015; 453 (3): 2341 DOI: 1093/mnras/stv1787
- Royal Astronomical Society (RAS). (2015, September 24). Too big for its boots: Black hole is 30 times expected size. ScienceDaily. Retrieved September 27, 2015 from sciencedaily.com/releases/2015/09/150924083634.htm
- Solar System. (2015, September 28). InWikipedia, The Free Encyclopedia. Retrieved 20:36, October 3, 2015, fromhttps://en.wikipedia.org/w/index.php?title=Solar_System&oldid=683170027
- Gillessen, S.; et al. (2009). Monitoring stellar orbits around the massive black hole in the Galactic Center.Astrophysical Journal 692 (2): 1075–1109. DOI: 1088/0004-637X/692/2/1075