ALMA unveils the mystery about the properties of the most luminous quasar host galaxy at high redshift

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Created: Sunday, 12 February 2023 12:36

Quasars are certainly among the most mysterious objects in the Universe. And without any doubts, the quasar J0100+2802 is one of the most interesting quasars known to date, since it is the most luminous quasar with the most massive black hole at redshift z>6 (i.e. less than 900 million years from the beginning of the Universe).

Given the importance and peculiarity of J0100+2802, it has been studied in many wavelength regimes by different instruments. In particular, researchers have analyzed the properties of the gas and dust in J0100’s host galaxy using the ALMA telescope in the submillimeter band. The main goal was to better understand the complex relation between the black hole and its host galaxy and the mechanisms that regulate this relation.

Up to now, researchers were not able to determine precisely the dust properties of this object, such as the temperature, the mass and the emissivity of the dust. These quantities are tightly related to the star formation rate of the host galaxy, and therefore they are fundamental in studying the evolution of the galaxy. A new amazing ALMA observation at high frequency has allowed us to obtain a precise determination of these properties (<10% uncertainty on the dust temperature, <15% uncertainty on the star formation rate). This is the first time the ALMA telescope has been exclusively used to achieve these precise results on high redshift quasars.

This observation also enabled us to evaluate the evolutionary scenario of this object: specifically, we found that the black hole is dominating the growth of the black hole-host galaxy system in J0100 at the time we observe it (i.e. z=6.3, about 860 million years from the Big Bang). This result highlights the critical role of ALMA in obtaining reliable and precise information about the characteristics of quasars and their evolutionary scenarios. We have just touched the surface of the potentiality of ALMA and we plan to improve and extend our work using other quasars and new techniques. Stay tuned!

 

 
ArXiv: https://arxiv.org/abs/2303.11961
 

 An artist's impression of a quasar (Credit: ESO/MKornmesser)