By analyzing data from astronomical surveys, Japanese astronomers have detected a new, extremely variable quasi-stellar object (QSO), or quasar. The newly found object, designated SDSS J125809.31+351943.0, brightened in optical band for 4.0 mag over three decades, which means that it was one of the largest quasar brightening events so far recorded. The finding is reported in a paper published November 3 on arXiv.org.
Quasars are active galactic nuclei of very high luminosity, emitting electromagnetic radiation observable in radio, infrared, visible, ultraviolet and X-ray wavelengths. They are among the brightest and most distant objects in the known universe, and serve as fundamental tools for numerous studies in astrophysics as well as cosmology. For instance, quasars have been used to investigate the large-scale structure of the universe and the era of reionization. They also improved our