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Unveiling the Chemical Enrichment of RXJ1007+3800 Fossil Groups

Presentation #148.02 in the session “Galaxies and Galaxy Clusters”.

Published onJan 11, 2021
Unveiling the Chemical Enrichment of RXJ1007+3800 Fossil Groups

Fossil Group (FG) of galaxies are systems of galaxies dominated by a central galaxy (cD), whose difference in magnitude in the R band compared to the second brightest galaxy is at least 2 mag within 0.5R200 of the system, and are brilliant sources of extensive X-ray emission (LX,bol>1042h−250 erg/s). FGs are believed to be old galaxy systems groups, the dominant galaxies of which have grown by accreting surrounding galaxies through dynamic friction. The large difference in magnitude and the apparent absence of X-ray substructures indicate that FGs have not undergone significant mergers with other systems for a long time. However, the lack of developed cool cores in central regions is a puzzle to this scenario, suggesting a more recent formation time. XMM-Newton observation of RX J1007+3800 shows a higher central temperature than the outskirts. This negative radial temperature gradient is not consistent with the current picture of FG’s old formation epoch. From spatially resolved spectra, we also found a negative Fe radial abundance gradient towards the center, where the abundances reach supersolar values. To evaluate the relative enrichment contribution in the ICM from different scenarios, it is necessary to determine the mass fraction of the gas that is produced by both Type Ia and core collapse supernovae. For that we used the best supernova explosion models following the prescription of Batalha, Dupke & Jimenez-Teja (2020), who used the metallicity of the ICM itself to discriminate among SNe explosion models. Here, we show the results for the SN Ia Fe mass fraction radial distribution and discuss the impact on the metal enrichment mechanisms of fossil groups.

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