The Fornax Cluster is a low-mass cool-core galaxy cluster. We present a deep Chandra study of NGC 1399, the central dominant elliptical galaxy of Fornax. The cluster center harbors two symmetric X-ray cavities coincident with a pair of radio lobes fed by two collimated jets along a north-south axis. A temperature map reveals that the active galactic nucleus (AGN) outburst has created a channel filled with cooler gas out to a radius of 10 kpc. The cavities are surrounded by cool bright rims and filaments that may have been lifted from smaller radii by the buoyant bubbles. X-ray imaging suggests a potential ghost bubble of 5 kpc diameter to the northwest. We find that the amount of gas lifted by AGN bubbles is comparable to that which would otherwise cool, demonstrating that AGN-driven outflow is effective in offsetting cooling in low-mass clusters. The cluster cooling timescale is times longer than the dynamical timescale, which is consistent with the lack of cold molecular gas at the cluster center. The X-ray hydrostatic mass is consistent within 10%, with the total mass derived from the optical data. The observed entropy profile rises linearly, following a steeper slope than that observed at the centers of massive clusters; gas shed by stars in NGC 1399 may be incorporated in the hot phase. However, it is far-fetched for supernova-driven outflow to produce and maintain the thermal distribution in NGC 1399, and it is in tension with the metal content in the hot gas.
|State||Published - Oct 1 2017|
Bibliographical noteFunding Information:
This work was supported by Chandra Award GO1-12160X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory under NASA contract NAS8-03060.
© 2017. The American Astronomical Society. All rights reserved..
- ISM: bubbles
- X-rays: galaxies: clusters
- galaxies: clusters: intracluster medium
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science