An essential to resolving this problem depends on the early universe, where the time expired because the Big Bang (i.e., the beginning of deep space) was less than a billion years. Thanks to the finite speed of light, we can recall at the past by observing the far-off universe. Did SMBHs currently exist when deep space was just a billion years of ages or less?
An example of the night-sky picture we took with the Subaru Telescope. The tiny red dot at the center of the amplified image represents the light from a remote quasar, which existed when deep space was 800 million years old (13 billion light-years away). Credit: National Astronomical Observatory of Japan
Is it possible for a great void to acquire such a big mass (exceeding a million solar masses and in some cases reaching billions of solar masses) in such a brief time? If so, what are the underlying physical systems and conditions? To surround the origin of SMBHs, one requires to observe them and compare their homes with forecasts from theoretical models. To do this, one first needs to find where they remain in the sky.
The research team used the Subaru Telescope at the top of Maunakea, Hawaii, for today study. Among the most significant benefits of Subaru is its widefield observing capability, which is particularly fit for this function.
Since SMBHs do not release light, the group tried to find an unique class called “quasars”– SMBHs with shining borders where the infalling product launches gravitational energy. They observed a large sky area comparable to 5000 times the full moon and effectively discovered 162 quasars living in the early universe. In specific, 22 of these quasars existed in the era when the universe was less than 800 million years of ages– the most ancient period in which quasars have actually been acknowledged to date.
The a great deal of quasars found has actually allowed them to determine the most essential measure called the “luminosity function,” which describes the area density of quasars as a function of radiation energy. They found that quasars were forming extremely rapidly in the early universe, while the general shape of the luminosity function (other than for the amplitude) stayed unchanged gradually.
We plot the luminosity functions of quasars observed when the age of the universe was 0.8 (red dots), 0.9 (green diamonds), 1.2 (blue squares), and 1.5 (black triangles) billion years. The space density of quasars increased steeply over time, while the shape of the luminosity function stays nearly unchanged.
This characteristic habits of the luminosity function offers strong restraints on theoretical models, which could ultimately recreate all the observables and describe the origin of SMBHs.
On the other hand, deep space was understood to have actually experienced a major phase transition called “cosmic reionization” in its early stage. Past observations recommend that the whole intergalactic area was ionized in this event. The source of the ionization energy is still under dispute, with radiation from quasars being thought about as a promising prospect.
By integrating the above luminosity function, we found that quasars discharge 1028 photons per second in a system volume of 1 light-year on a side in the early universe. This is less than 1% of the photons required to maintain the ionized state of the intergalactic space at that time and hence indicates that quasars made just a minor contribution to cosmic reionization. Other energy sources are seriously required, which, according to other recent observations, might be the integrated radiation from huge hot stars in forming galaxies.
Referral: “Quasar Luminosity Function at z = 7” by Yoshiki Matsuoka, Masafusa Onoue, Kazushi Iwasawa, Michael A. Strauss, Nobunari Kashikawa, Takuma Izumi, Tohru Nagao, Masatoshi Imanishi, Masayuki Akiyama, John D. Silverman, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Kohei Inayoshi, Rikako Ishimoto, Toshihiro Kawaguchi, Satoshi Kikuta, Kotaro Kohno, Yutaka Komiyama, Chien-Hsiu Lee, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Atsushi J. Nishizawa, Masamune Oguri, Yoshiaki Ono, Taira Oogi, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Ayumi Takahashi, Tadafumi Takata, Masayuki Tanaka, Yoshiki Toba, Shiang-Yu Wang and Takuji Yamashita, 6 June 2023, The Astrophysical Journal Letters.DOI: 10.3847/ 2041-8213/ acd69f.
The research study was funded by the Japan Society for the Promotion of Science, the Mitsubishi Foundation, and the National Natural Science Foundation of China.
A supermassive black hole (SMBH; the small black dot at the center) absorbs surrounding product, which forms a spiral disk-like shape as it flows in. The gravitational energy of the material is transformed to radiation and gave off away from the disk.
Black holes with remarkably large masses– over a million times the mass of the Sun, referred to as supermassive black holes (SMBHs)– are frequently found in deep space today. Nevertheless, their origins, along with the specifics of when, where, and how they came to be over the course of 13.8 billion years of cosmic development, remain uncertain.
Research covering the last several decades shows that a SMBH lives at the core of each galaxy, and its mass is practically always about one-thousandth that of its host galaxy.
This close relationship indicates that smbhs and galaxies have actually co-evolved together. Exposing the origin of SMBHs is thus essential not only to understand SMBHs themselves but likewise to illuminate the development processes of galaxies, the major constituents of the noticeable universe.
The tiny red dot at the center of the magnified image represents the light from a distant quasar, which existed when the universe was 800 million years old (13 billion light-years away). Given that SMBHs do not produce light, the team looked for a special class called “quasars”– SMBHs with shining borders where the infalling material releases gravitational energy. In particular, 22 of these quasars existed in the period when the universe was less than 800 million years old– the most ancient duration in which quasars have been acknowledged to date.
We plot the luminosity functions of quasars observed when the age of the universe was 0.8 (red dots), 0.9 (green diamonds), 1.2 (blue squares), and 1.5 (black triangles) billion years. By integrating the above luminosity function, we found that quasars give off 1028 photons per second in an unit volume of 1 light-year on a side in the early universe.
