The James Webb Space Telescope has taken the most detailed images of the universe since it was launched in December of 2021. The kinds of observations we can look forward to are ones where the JWST will use its advanced capabilities to address some of the most pressing mysteries. There is a problem presented by bright quasars that existed during the first billion years of the Universe.
Astronomers have not been able to figure out how SMBHs formed. Stars in host galaxies with redshift values of Z>2 have been hard to find. An international team of astronomer recently observed stars in quasars at Z>6 for the first time. The processes that governed the formation and evolution of the first SMBHs could be assessed by their observations.
The team was made up of astronomer from all over the world, including Japan, China, Europe, the U.K., the US, Brazil, Taiwan, and Israel. The National Astronomy Observatory of Japan (NAOJ) is one of the notable institutions. The study is being reviewed for publication in the journal Nature.
High-redshift galaxies were limited by data quality and unable to provide the necessary high-quality point spread function. The ability to get high-resolution and focused images of a distant point source of light is described. In order to shed some light on the new observations, Universe Today spoke with project lead and lead author Xuheng Ding and co-authors Masafusa Onoue and John D. They related in an email.
“Basically, to reveal the host galaxy of a quasar, the quasar+host image decomposition needs to be performed. The quasar is a point source which is unresolved and can be described by a scaled PSF. Usually, this information of PSF is from the isolated stars in the field of view.
“Besides, the JWST has higher resolution data and can observe the redder wavelength compared with the HST to allow this study to the higher redshift sample. Another advantage of this program is that we proposed to observe the lower luminosity quasar, which makes the subtraction of quasar images easier.”
Two relatively low-luminosity quasars were chosen for their research. This corresponds to a distance of about 25.11 billion light-years when the light we see leaves these objects. The quasars were identified as part of a survey. The low-luminosity quasars that were observed were one billion years after the Big bang.
The quasars are the subject of follow up observations by the JWST program to study high-redshift galaxies and observe the stars in their disks for the first time. The team looked at the data obtained by the Near-Infrared Camera and then looked at the glare of the quasars. They compared their observations with simulations of quasars. The features of these quasars and their SMBHs made them stand out.
The results showed that the two quasars are large and compact. The central positions are offset to the quasars, which may mean that the SMBH are not at the center of the gravity well yet.
The recent observations of Z>6 quasar host galaxies rely on the ALMA. The offsets in early quasars were noted by these observations. The offsets may be due to asymmetries created by tidal forces or the clumpy accretion of cold gas. The hypotheses will be tested in further papers based on the data from the NIRSpec. They said:
“The importance of this first paper highlights the tremendous power of JWST and proof that the detection of the quasar host at z>6 is possible. Eventually, our program will establish the first z~6 quasar measurements of the host stellar mass and SMBH mass relation, which will be used to understand their co-evolution of the galaxy and its central SMBH. These works will also be useful in understanding the origin of SMBH in the early Universe.”
ArXiv is further reading.
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