Revealed: New Hyperluminous Quasar in Space

An international group of astronomers has announced the discovery of a new hyperluminous quasar, named eFEDSJ0828–0139. This quasar is notable for its high star-formation rate and the fact that its black hole is accumulating mass at a rate that exceeds the Eddington limit. The findings were detailed in a research paper published on August 16 on the arXiv preprint server.

Quasars, also called quasi-stellar objects (QSOs), are active galactic nuclei (AGN) powered by supermassive black holes (SMBHs). They emit electromagnetic radiation across various wavelengths, including radio, infrared, visible, ultraviolet, and X-ray. These objects are some of the brightest and most distant entities in the universe and play a critical role in both astrophysics and cosmology.

Led by Yoshiki Toba from the National Astronomical Observatory of Japan (NAOJ), the team identified this new quasar with a bolometric luminosity exceeding 290 quattuordecillion erg/s. The quasar was initially detected by the eROSITA instrument aboard the Spektr-RG spacecraft, and its nature was confirmed with observations from the Seimei Telescope and the James Clerk Maxwell Telescope (JCMT).

"We conducted optical spectroscopic observations with KOOLS-IFU on the Seimei Telescope (...) To accurately measure its infrared luminosity (LIR), we used submillimeter data from SCUBA-2 on JCMT and analyzed the spectral energy distribution from X-ray to submillimeter data," the researchers noted.

According to the paper, eFEDSJ0828–0139 has a spectroscopic redshift of 1.62, and its SMBH has a mass of about 620 million solar masses. The quasar exhibits an incredibly high infrared luminosity, measured at 68 trillion solar luminosities, with an Eddington ratio of 3.6. This confirms that the quasar is hyperluminous and has a very high black hole mass accretion rate.

The study also found that eFEDSJ0828–0139 has an exceptionally high star-formation rate (SFR), estimated at 1,000 solar masses per year.

In conclusion, the researchers suggest that eFEDSJ0828−0139 may be in a phase where both its SMBH and host galaxy are actively growing, consistent with the co-evolution model of galaxies and their central black holes. They further noted that this discovery indicates that many more hyperluminous quasars could be found using the eROSITA all-sky survey and next-generation spectrographs like the Subaru Prime Focus Spectrograph (PFS).