Are quasars black holes
Pro Research Analysisby 
Searched over 200M research papers
Are Quasars Black Holes?
Introduction to Quasars and Black Holes
Quasars are among the most luminous and energetic objects in the universe. They are often observed at great distances, providing a glimpse into the early universe. The central question is whether quasars are black holes or if they are powered by black holes.
Quasars as Supermassive Black Holes
Evidence from Observations
Multiple studies have shown that quasars are indeed powered by supermassive black holes. For instance, the discovery of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.30 revealed a black hole with a mass of approximately 12 billion solar masses . Similarly, the quasar ULAS J134208.10+092838.61 at redshift 7.54 was found to have a black hole mass of 800 million solar masses . These findings indicate that quasars host extremely massive black holes at their centers.
The Role of Accretion
Quasars are characterized by their rapid accretion of material onto these supermassive black holes. This accretion process releases enormous amounts of energy, making quasars some of the brightest objects in the universe. The diversity in quasar properties can be largely explained by variations in the Eddington ratio, which is the luminosity of the quasar normalized by the mass of the black hole .
Theoretical Models and Simulations
Black Hole Growth and Galaxy Formation
Simulations have shown that the growth of supermassive black holes and the formation of galaxies are closely linked. During galaxy mergers, gas inflows feed the black hole, powering the quasar and regulating both star formation and black hole growth . This interaction helps explain the observed relationship between black hole mass and the velocity dispersion of stars in the host galaxy.
Early Universe Quasars
The existence of quasars with supermassive black holes in the early universe poses challenges to our understanding of black hole formation. These black holes must have grown rapidly, possibly through episodic hyper-Eddington accretion or from massive initial seeds 47. Observations of quasars at high redshifts provide crucial insights into the early stages of black hole and galaxy formation.
Alternative Models
Spinar Model
While the black hole model is widely accepted, there are alternative theories such as the spinar model. However, recent developments in accretion disk theory support the black hole model, even for quasars with short periodicities in their flux variations .
Conclusion
In summary, the overwhelming evidence from observations and theoretical models supports the conclusion that quasars are powered by supermassive black holes. These black holes, through their accretion processes, generate the immense luminosity that characterizes quasars. The study of quasars not only enhances our understanding of black holes but also provides valuable insights into the formation and evolution of galaxies in the early universe.
Sources and full results
Most relevant research papers on this topic