Cooling in the X-ray halo of the rotating, massive early-type galaxy NGC 7049

A. Juráňová, N. Werner, M. Gaspari, K. Lakhchaura, P. E.J. Nulsen, M. Sun, R. E.A. Canning, S. W. Allen, A. Simionescu, J. B.R. Oonk, T. Connor, M. Donahue

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The relative importance of the physical processes shaping the thermodynamics of the hot gas permeating rotating, massive early-type galaxies is expected to be different from that in non-rotating systems. Here, we report the results of the analysis of XMM-Newton data for the massive, lenticular galaxy NGC 7049. The galaxy harbours a dusty disc of cool gas and is surrounded by an extended hot X-ray emitting gaseous atmosphere with unusually high central entropy. The hot gas in the plane of rotation of the cool dusty disc has a multitemperature structure, consistent with ongoing cooling. We conclude that the rotational support of the hot gas is likely capable of altering the multiphase condensation regardless of the t cool /t ff ratio, which is here relatively high, ∼40. However, the measured ratio of cooling time and eddy turnover time around unity (C-ratio ≈ 1) implies significant condensation, and at the same time, the constrained ratio of rotational velocity and the velocity dispersion (turbulent Taylor number) Ta t > 1 indicates that the condensing gas should follow non-radial orbits forming a disc instead of filaments. This is in agreement with hydrodynamical simulations of massive rotating galaxies predicting a similarly extended multiphase disc.

Original languageEnglish
Pages (from-to)2886-2895
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - 1 Apr 2019


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