Speaker
Description
Galaxy groups play a crucial role in shaping the large-scale structure. They have relatively shallower potential wells compared to clusters, which makes them much more sensitive to non-gravitational processes such as AGN feedback. eROSITA's observation strategy, combined with its high soft band sensitivity, makes it an ideal instrument for detecting galaxy groups and studying the thermodynamic properties of the intra-group medium. In our work, we investigate the impact of AGN feedback on the thermodynamic properties of galaxy groups to improve our understanding of the feedback mechanisms and help guide future simulations for future AGN feedback implementations. We quantify the impact of feedback on the intra-group medium by measuring thermodynamic properties, such as electron density, temperature, and entropy at three characteristic radii (0.15r500, r2500, and r500) as a function of the characteristic temperature, T(r < r500), for 1178 galaxy groups detected in the first All-Sky Survey observations of eROSITA (eRASS1). We measure thermodynamic properties by co-fitting X-ray images and spectra of the galaxy groups in our sample in 271 bins using deeper eRASS:4 observations following the Bayesian approach. Furthermore, we quantify the impact of various systematics on our measurements and consider them as part of our total error budget. Having the largest galaxy group sample, we achieve the tightest constraints for the impact of AGN on the thermodynamic properties of the intra-group medium in X-ray studies. Overall, we find that our measurements agree relatively well with the previous measurements when we compare our results with the literature. We also find that our results significantly favor the presence of strong AGN feedback when we compare our measurements with the reference run of the OWL simulations that include various subgrid physics except the AGN feedback. In addition to the reference run of the OWL simulations, we also compare our results with the state-of-the-art numerical simulations (MillenniumTNG, Magneticum, and the AGN run of the OWL simulations) employing different AGN feedback implementations by taking into account the selection effects. As a result of this comparison, we find that our observations lay above the simulations at the outskirts (r2500 and r500) and below at the cores (0.15r500). Overall, we find that our measurements at the three radii agree the best with Magneticum simulations. Our study marks as the most comprehensive study of the intra-group medium in terms of sample size, diversity, and statistics, and it will pave the way to achieving more realistic AGN feedback implementations in simulations.
