PSO J0309 + 27 – in short – was discovered by a team of researchers led by Silvia Belladitta, a PhD student at the University of Insubria, working for the Italian National Institute for Astrophysics (INAF) in Milan, under the supervision of Alberto Moretti and Alessandro Caccianiga. While it was suspected that the object was distant, and observations from the Swift Space Telescope (of which INAF is a major contributor) showed its X-ray power matched that of other Blazars, it was the observations obtained with the optical Multi-Double Object Spectrographs (MODS) at the Large Binocular Telescope (LBT) that confirmed it indeed broke the record as the most distant Blazar in the known Universe.
“The spectrum that appeared before our eyes confirmed first that PSO J0309 + 27 is actually an AGN, or a galaxy whose central nucleus is extremely bright due to the presence, in its center, of a supermassive black hole fed by the gas and the stars it engulfs, ”says Belladitta. “In addition, the data obtained by LBT also confirmed that PSO J0309 + 27 is really far away from us using the shift of the color of its light towards red or redshift with a record value of 6.1, never measured before for a similar object,” adds Belladitta, first author of the paper describing the discovery, published today in the journal Astronomy & Astrophysics Letters.
PSO J0309 + 27 has therefore proved to be, at the moment, the most powerful persistent radio source in the primordial universe, within the first billion years since its formation. Observations taken by the XRT telescope on board the Swift satellite – a mission with a fundamental contribution by INAF and the Italian Space Agency – have also made it possible to establish that, even in X-rays, PSO J0309 + 27 is the brightest cosmic source ever observed at these distances.
Belladitta notes further, “Observing a blazar is extremely important, for every discovered source of this type, we know that there must be a hundred similar, but oriented differently and therefore too weak to be seen directly”. Therefore, the discovery of PSO J0309 + 27 allows astronomers to quantify, for the first time the number of AGN with powerful relativistic jets present in the primordial universe. The Blazars at these early epochs represent the “seeds” for all SMBHs that exist in the Universe today.
INAF press release: https://www.media.inaf.it/2020/03/06/blazar-da-record/
S. Belladitta, A. Moretti, A. Caccianiga, C. Spingola, P. Severgnini, R. Della Ceca, G. Ghisellini, D. Dallacasa, T. Sbarrato, C. Cicone, L. P. Cassarà, and M. Pedani. link to the pdf version
A&A 635, L7 (2020)